JP2002198285A - Stage device and its damping method and projection aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contribute to improvement in exposure accuracy. SOLUTION: The pattern of a mask R is projected onto a substrate W by a projection optical system PL for exposure. There are detection devices 73 and 74, and a drive control device. The detection devices 73 and 74 detect the relative speed between the projection optical system PL regarding the direction of nearly an optical axis of the projection optical system PL, and the substrate W. In the drive control device, based on a result detected by the detection devices 73 and 74, at least the substrate W is followed in the optical axis direction to the projection optical system PL for drive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage apparatus in which a stage body for holding a sample such as a mask or a substrate moves.
And a vibration damping method for controlling vibration in the stage apparatus, and an exposure apparatus for performing an exposure process using a mask and a substrate held by the stage apparatus, and particularly to manufacturing devices such as semiconductor integrated circuits and liquid crystal displays. The present invention relates to a stage apparatus suitable for use in a lithography process, a vibration damping method thereof, and an exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, in a lithography process which is one of the manufacturing processes of a semiconductor device, a circuit pattern formed on a mask or a reticle (hereinafter referred to as a reticle) is coated with a resist (photosensitive agent) on a wafer. Alternatively, various exposure apparatuses for transferring the image onto a substrate such as a glass plate have been used.

For example, as an exposure apparatus for a semiconductor device, a pattern of a reticle is projected using a projection optical system in accordance with the miniaturization of the minimum line width (device rule) of a pattern accompanying the high integration of an integrated circuit in recent years. A reduction projection exposure apparatus that performs reduction transfer on a wafer is mainly used.

As this reduction projection exposure apparatus, a step-and-repeat type static exposure reduction projection exposure apparatus (so-called stepper) for sequentially transferring a reticle pattern to a plurality of shot areas (exposure areas) on a wafer.
And an improved version of this stepper.
No. 043, etc., a reticle and a wafer are synchronously moved in a one-dimensional direction to transfer a reticle pattern to each shot area on the wafer. Scanning steppers) are known.

In these reduction projection exposure apparatuses, as a stage apparatus, first, a base plate serving as a reference of the apparatus is installed on a floor surface, and a reticle stage, a wafer, and a wafer are placed on the base plate via a vibration isolating table for isolating floor vibration. A stage on which a main body column supporting a stage, a projection optical system (projection lens), and the like is mounted is often used. In recent stage devices, an actuator (thrust applying device) such as an air mount or a voice coil motor capable of controlling the internal pressure is provided as the vibration isolating table, and for example, six accelerations attached to a main body column (main frame) are provided. An active anti-vibration table that controls the vibration of the main body column by controlling the thrust of the voice coil motor or the like based on the measurement value of the meter is employed.

The above-mentioned stepper or scanning stepper repeats exposure to a shot area on a wafer and then to other shot areas sequentially, so that a wafer stage (in the case of a stepper),
Alternatively, the reaction force generated by the acceleration and deceleration movements of the reticle stage and wafer stage (in the case of a scanning stepper) causes vibration of the main body column, causing a relative position error between the projection optical system and the wafer or the like. When the pattern is transferred to a position different from the design value or when the position error includes a vibration component, there is a problem that image blurring (increase in pattern line width) is caused.

Therefore, conventionally, in the above-described active vibration isolating table, vibrations caused by a reaction force applied to the surface plate when the stage body moves on the surface plate are calculated by using parameters of the apparatus calculated in advance, for example, the center of gravity of the body, The inconvenience described above has been suppressed by controlling the dynamic characteristics of the body using an inertia spindle, a servo gain, a decoupling block, and the like. In addition, as described in, for example, Japanese Patent Application Laid-Open No. 8-166475, a reaction force generated by movement of a wafer stage is mechanically controlled by using a frame member which is arranged vibrationally independent of a surface plate. In addition, inventions that escape to the floor (ground),
As described in Japanese Patent No. 0224 or the like, a reaction force generated by the movement of the reticle stage is mechanically released to the floor (ground) by using a frame member which is arranged independently in vibration with respect to the surface plate. The invention is known to remedy the above disadvantages.

Further, conventionally, a configuration in which a projection optical system and a stage device for moving a wafer, for example, are integrated has been adopted, and these vibrations almost follow, but in recent years, these components are independently installed. In addition, a method of suppressing the transmission of vibration due to the movement of the stage to the projection optical system by individually providing an active vibration isolation table and controlling the vibration has been studied.

[0009]

However, the following problems exist in the above-described conventional stage apparatus, its vibration control method, and exposure apparatus. In recent years, there has been an increasing demand for miniaturization of semiconductor devices and high-speed exposure processing, and there has been a strong demand for a stage apparatus and an exposure apparatus which can meet this demand. However, even when controlling the vibration of the stage device using parameters calculated in advance by a computer or the like, there is a slight difference between the actual machine and the calculated value, so the residual vibration of the body vibration is inevitably worse than the calculated value, There is a problem that it hinders the improvement of the exposure accuracy.

In recent years, in order to suppress a relative position error between a projection optical system and a wafer or the like, recently, the position of a stage measured by a laser interferometer or the like is feedback controlled.
Since the controllability is superior to that of the so-called position control method, a so-called speed control method of performing feedback control of the stage speed is employed. However, in this case, even if the vibration of the stage device alone is controlled with high accuracy, if the projection optical system vibrates, these follow-up controls cannot be sufficiently performed, and the relative position between the projection optical system and the wafer or the like is maintained. There was a problem that it was not possible.

In order to improve the exposure accuracy, an alignment operation or an exposure operation is started after the wafer stage is positioned at a desired position and sufficiently settled.
In the case of the scanning stepper, it is conceivable that the vibration of the main body column is sufficiently attenuated by the above-described active vibration isolating table or the like, for example, by performing exposure in a state where the synchronous setting of the reticle stage and the wafer stage is sufficiently secured. . However, in this case, the throughput (productivity) is deteriorated, which is not practical. For example, the wafer stage moves on the surface plate according to the position of the shot area, but when this wafer stage moves outside the surface plate, the vibration in the rotation direction becomes larger than the vibration on the center side, and the time required for settling is increased. There was a problem of becoming long.

On the other hand, when the mover provided on the stage moves with respect to the stator, a reaction force accompanying the movement acts on the stator, and this reaction force is mechanically applied to the floor (ground) using a frame member. In the case where the stator is released, a reaction force can be transmitted to the frame member while controlling the position of the stator by interposing a voice coil motor or the like between the stator and the frame member. However, since this reaction force reaches 1000 N, a large-sized voice coil motor is required, and there is a problem that the apparatus is increased in size and cost is increased.

The present invention has been made in consideration of the above points, and has as its object to provide a stage device which contributes to an improvement in exposure accuracy, a vibration damping method thereof, and an exposure device. Another object of the present invention is to provide a stage apparatus and an exposure apparatus that contribute to an improvement in throughput. Still another object of the present invention is to provide a stage apparatus and an exposure apparatus that contribute to downsizing of the apparatus.

[0014]

In order to achieve the above object, the present invention employs the following structure corresponding to FIGS. 1 to 11 showing an embodiment. According to the vibration damping method for a stage device of the present invention, a thrust is applied to a surface plate (6) to a stage device (7) having a stage body (5) driven on the surface plate (6) to suppress the vibration. A method of detecting a position of a center of gravity and a principal axis of inertia in a stage device (7) when a platen (6) is vibrated, and correcting a thrust based on the detected position of the center of gravity and a principal axis of inertia. It is assumed that.

Therefore, in the vibration control method for the stage device of the present invention, the surface plate (6) is vibrated on the actual machine or detected by simulation instead of the position of the center of gravity and the main axis of inertia in design. The thrust is corrected based on the actual position of the center of gravity and the principal axis of inertia when the vibration is applied.
Can be effectively suppressed.

The stage device of the present invention comprises a stage body (5) driven on a surface plate (6) and a thrust applying device (31) for applying a thrust to the surface plate (6). A detecting device (74) for detecting a position of a center of gravity and an inertia main axis of the stage device (7) when the surface plate (6) is vibrated, and a detection result of the detecting device (74) And a correcting device (70) for correcting the thrust applied to the surface plate (6) based on the

Therefore, in the stage device of the present invention, the surface plate (6) is vibrated in an actual machine or the surface plate (6) detected by simulation is vibrated instead of the position of the center of gravity and the inertia main axis in design. Since the thrust is corrected based on the actual position of the center of gravity and the inertia main axis at this time, the residual vibration of the surface plate (6) can be effectively suppressed.

The stage device of the present invention is a stage device (7) having a stage main body (5) driven on a surface plate (6), and has a stator (35a) and a mover. And a driving device (3) for driving the stage body (5).
5), a support portion (8) disposed independently of the platen (6) in terms of vibration, and a stage body interposed between the support portion (8) and the stator (35a). A reaction force transmitting device (34) for transmitting a reaction force generated on the stator (35a) by the movement of (5) to the support portion (8);
Is characterized by having an EI core formed by bonding an E-type core and an I-type core.

Therefore, in the stage apparatus of the present invention, the EI
Since the core can output about 1.5 times as much thrust as the voice coil motor, to output the same thrust, 2 /
The reaction force can be transmitted to the support portion (8) by the EI core having a size of about 3 and the size of the device can be reduced.

The stage device of the present invention comprises a stage body (56) driven on a surface plate (6) and a thrust applying device (31) for applying thrust to the surface plate (6). An apparatus (7), a storage device (76) for storing vibration characteristics of the surface plate (6) corresponding to the position of the stage body (5), and a vibration detection device for detecting the vibration characteristics of the surface plate (6) (74) and a control device (70) that controls the driving of the thrust applying device (31) based on the detection result of the vibration detection device (74) and the storage content of the storage device (76). Is what you do.

Therefore, in the stage device of the present invention, since the vibration characteristics such as residual vibration generated according to the position of the stage body (5) can be grasped in advance, the stage device can be obtained based on the vibration characteristics detected by the vibration detection device (74). Thus, it is possible to estimate the vibration characteristics generated in the surface plate (6). Therefore, the residual vibration of the surface plate (6) can be attenuated by the feedforward control, so that the time required for settling can be shortened.

The exposure apparatus according to the present invention is an exposure apparatus (1) for exposing a pattern of a mask (R) held on a mask stage (2) to a substrate (W) held on a substrate stage (5). The stage device (7) according to any one of claims 4 to 9 is used as at least one of the mask stage (2) and the substrate stage (5). It is.

Therefore, in the exposure apparatus of the present invention, the residual vibration of the surface plate (6) when the mask (R) or the substrate (W) is moved can be effectively suppressed, and a small stage apparatus can be used. According to (7), the mask (R) or the substrate (W) can be moved. Further, the settling time can be shortened even when positioning the stage (5), so that the throughput can be improved.

Further, the exposure apparatus of the present invention provides a mask (R)
In the exposure apparatus (1) for projecting and exposing the pattern on the substrate (W) by the projection optical system (PL),
A detection device (73, 74) for detecting a relative speed between the projection optical system (PL) and the substrate (W) in the substantially optical axis direction of L).
And a drive control device (70) that drives at least the substrate (W) to follow the projection optical system (PL) in the optical axis direction based on the detection results of the detection devices (73, 74). Is what you do.

Therefore, in the exposure apparatus of the present invention, even if the projection optical system (PL) vibrates, for example, the detection apparatus (7
3, 74) detected by the projection optical system (PL) and the substrate (W)
The substrate (W) can be made to follow the projection optical system (PL) under speed control using the relative speed with respect to the projection optical system (PL). Therefore, it is possible to maintain the relative position between the projection optical system (PL) and the substrate (W) and improve the pattern transfer accuracy. In this case, not only the substrate (W) but also the projection optical system (PL) can be driven.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a stage apparatus, a vibration damping method thereof, and an exposure apparatus according to the present invention will be described below with reference to FIGS. Here, for example, an example in which a scanning stepper (scanning type exposure apparatus) that transfers a circuit pattern of a semiconductor device formed on the reticle onto a wafer while synchronously moving the reticle and the wafer as an exposure apparatus is used. This will be described with reference to FIG. Also,
In this exposure apparatus, the stage device of the present invention is applied to a wafer stage.

The exposure apparatus 1 shown in FIG. 1 includes a light source LS (FIG. 2).
Reticle (mask) R by exposure illumination light from
An illumination optical system IU that illuminates an upper rectangular (or arc) illumination area with uniform illuminance, a reticle stage (mask stage) 2 that holds and moves a reticle R, and a reticle stage that supports the reticle stage 2. A stage device 4 including a board 3; a projection optical system PL for projecting illumination light emitted from a reticle R onto a wafer (substrate) W; and a wafer stage (substrate stage,
A stage device 7 includes a stage main body 5 and a wafer surface plate (surface plate) 6 that holds the wafer stage 5, and a reaction frame 8 that supports the stage device 4 and the projection optical system PL. Here, the optical axis direction of the projection optical system PL is defined as the Z direction, the direction of the synchronous movement of the reticle R and the wafer W is defined as the Y direction, and the direction of the asynchronous movement is defined as the X direction in a direction perpendicular to the Z direction. Also,
The rotation directions around the respective axes are θZ, θY, and θX.

Here, the light source LS has a wavelength of 192 to 192.
An ArF excimer laser light source that outputs pulsed ultraviolet light narrowed so as to avoid an oxygen absorption band between 194 nm is used, and the main body of the light source LS is a floor FD in a clean room of a semiconductor manufacturing plant. It is installed above. The light source LS is provided with a light source control device (not shown). The light source control device controls the oscillation center wavelength and the half width of the spectrum of the emitted pulsed ultraviolet light, triggers the pulse oscillation, and controls the inside of the laser chamber. Gas control and the like are performed. The light source LS has a wavelength of 24.
It may be used F ₂ laser light source for outputting a pulsed ultraviolet light of KrF excimer laser light source or a wavelength 157nm for outputting 8nm pulse ultraviolet light. Further, the light source LS may be installed in another room (service room) having a lower degree of cleanness than in the clean room, or in a utility space provided under the floor of the clean room.

As shown in FIG. 2, the light source LS is not shown in FIG. 2 for the sake of drawing. However, actually, one end of the beam matching unit BMU (incident light) is interposed via a light-shielding bellows and a pipe. End of the beam matching unit BMU.
It is connected to a first illumination optical system IU1 of the illumination optical system IU via a pipe 61 having a relay optical system built therein.
The beam matching unit BMU is provided with a relay optical system, a plurality of movable reflecting mirrors and the like (both not shown), and a narrow band pulse incident from the light source LS using these movable reflecting mirrors and the like. The optical path of ultraviolet light (ArF excimer laser light) is positionally matched with the first illumination optical system IU1.

The illumination optical system IU includes a first illumination optical system IU1.
And the second illumination optical system IU2. The first illumination optical system IU1 is installed on a base plate 10 called a frame caster, which is a reference of an apparatus mounted horizontally on the floor FD. Further, the second illumination optical system IU2 is supported from below by a support column 9 fixed to the upper surface of the reaction frame (support portion) 8. Therefore, the first illumination optical system IU1 and the reaction frame 8 (that is, the second illumination optical system IU2) are vibrationally independent.

The first illumination optical system IU1 includes a mirror, a variable dimmer, a beam shaping optical system, and a mirror arranged in a predetermined positional relationship.
An optical integrator, a condensing optical system, a vibration mirror, an illumination system aperture stop plate, a beam splitter, a relay lens system, and a movable reticle blind (illumination area setting device) 62 as a movable field stop constituting a reticle blind mechanism are provided. I have. When the pulsed ultraviolet light from the light source LS is horizontally incident on the first illumination optical system IU1 via the beam matching unit BMU and the relay optical system, the pulsed ultraviolet light is given a predetermined peak intensity by the ND filter of the variable dimmer. After that, the beam shaping optical system shapes the cross-sectional shape of the optical integrator so as to efficiently enter the optical integrator.

Next, when the pulsed ultraviolet light enters the optical integrator, a surface light source, that is, a secondary light source composed of a large number of light source images (point light sources) is formed on the exit end side. The pulsed ultraviolet light diverging from each of these many point light sources passes through one of the aperture stops on the illumination system aperture stop plate 28G, and then reaches the movable reticle blind 62 as exposure light.

As shown in FIG. 3, the movable reticle blind 62 has two L-shaped movable blades and an actuator 63 for driving the movable blades. The positions of the two movable blades in the direction corresponding to the scanning direction of the reticle R and the direction corresponding to the non-scanning direction orthogonal to the scanning direction are variable. The movable reticle blind 62 has a reticle R defined by a fixed reticle blind by a movable blade at the start and end of scanning exposure, as described later, in order to prevent exposure of unnecessary portions.
Used to further limit the upper illumination area. The driving of the movable reticle blind 62 is controlled by a main controller 70 described later as an adjusting device (see FIG. 6).

The second illumination optical system IU2 includes an illumination system housing 64, a fixed reticle blind, a lens, a mirror, a relay lens system, and a main condenser lens housed in the illumination system housing 64 in a predetermined positional relationship. (Not shown). The fixed reticle blind is arranged on a surface slightly defocused from a conjugate plane with respect to the pattern surface of the reticle R near the incident end of the illumination system housing 64, and an opening having a predetermined shape that defines an illumination area on the reticle R is formed. ing. The opening of the fixed reticle blind has a slit or rectangular shape linearly extending in the X-axis direction orthogonal to the moving direction (Y-axis direction) of the reticle R during scanning exposure at the center of the circular visual field of the projection optical system PL. It is assumed that it is formed in a shape.

The pulsed ultraviolet light passing through the opening of the blade of the movable reticle blind 62 illuminates the opening of the fixed reticle blind with a uniform intensity distribution. The pulsed ultraviolet light passing through the opening of the fixed reticle blind passes through a lens, a mirror M3, a relay lens system, and a main condenser lens system, and passes through a predetermined illumination area (X-axis direction) on a reticle R held on a reticle stage 2. Illuminating a slit-shaped or rectangular illumination area extending linearly with a uniform illuminance distribution. Here, the rectangular slit-shaped illumination light applied to the reticle R is set so as to extend in the X-axis direction (non-scanning direction) at the center of the circular projection field of the projection optical system PL in FIG. The width of the light in the Y-axis direction (scanning direction) is set substantially constant.

When the first illumination optical system IU1 and the second illumination optical system IU2 are firmly joined, the vibration generated in the first illumination optical system IU1 during the exposure operation due to the driving of the movable reticle blind 62 reacts. This is undesirably transmitted to the second illumination optical system IU2 supported by the frame 8 as it is. For this reason, in the present embodiment, between the first illumination optical system IU1 and the second illumination optical system IU2,
The two members are joined via a telescopic bellows-like member 65 as a connecting member that enables relative displacement between the two and makes the inside airtight with respect to the outside air.

In the first illumination optical system IU1, a position sensor (detection device) 66 such as a photoelectric sensor is provided near the second illumination optical system IU2, specifically, near the movable reticle blind 62. Are located. Position sensor 66
Is a movable reticle blind 62 and a second illumination optical system IU.
2 IU1 end (for example, fixed reticle blind)
Is detected on a two-dimensional plane defined by the X axis and the Y axis, and the detection result is output to the main controller 70 (see FIG. 6).

Returning to FIG. 1, the reaction frame 8
It is installed on a base plate 10 placed horizontally on the floor surface, and its upper and lower sides are formed with step portions 8a and 8b protruding inward, respectively.

In the stage device 4, the reticle platen 3
Step 8a of reaction frame 8 at each corner
An opening 3a through which a pattern image formed on the reticle R passes is supported in a substantially horizontal manner via an anti-vibration unit 11 (note that the anti-vibration unit on the back side of the drawing is not shown). Are formed. Note that metal or ceramics can be used as the material of the reticle surface plate 3. The anti-vibration unit 11 has a configuration in which an air mount 12 whose internal pressure can be adjusted and a voice coil motor 13 that applies thrust to the reticle surface plate 3 are arranged in series on the step 8a. The base plate 10 and the reaction frame 8 are
The micro-vibration transmitted to the reticle surface plate 3 through the reticle is insulated at the micro G level (G is the gravitational acceleration).

A reticle stage 2 is supported on the reticle base 3 so as to be two-dimensionally movable along the reticle base 3. A plurality of air bearings (air pads) are provided on the bottom of the reticle stage 2 as non-contact bearings.
The reticle stage 2 is levitated and supported by the air bearings 14 on the reticle surface plate 3 with a clearance of about several microns.
At the center of the reticle stage 2, there is formed an opening 2a which communicates with the opening 3a of the reticle platen 3 and through which the pattern image of the reticle R passes. A plurality of (for example, three, only one is shown in FIG. 1) accelerometers 75 are provided on the reticle surface plate 3. The measurement result of the accelerometer 75 is output to a main controller 70 described later (FIG. 6).
reference).

The reticle stage 2 will be described in detail.
As shown in FIG. 4, the reticle stage 2 includes a reticle coarse movement stage 16 driven on the reticle surface plate 3 by a pair of Y linear motors 15 and 15 in a predetermined stroke in the Y-axis direction. A pair of X above
A reticle fine movement stage 18 that is finely driven in the X, Y, and θZ directions by a voice coil motor 17X and a pair of Y voice coil motors 17Y is provided. As illustrated).

Each Y linear motor 15 has a reticle surface plate 3
A stator 20 floating above and supported in the Y-axis direction by a plurality of air bearings (air pads) 19 as non-contact bearings, and a reticle coarse movement stage provided corresponding to the stator 20 via a connecting member 22 The movable element 21 is fixed to the movable element 16. Therefore, the reticle coarse movement stage 16 has + Y
In accordance with the movement in the direction, the stator 20 moves in the −Y direction. The movement of the stator 20 cancels the reaction force caused by the movement of the reticle coarse movement stage 16 and can prevent a change in the position of the center of gravity.

The stator 20 may be provided on the reaction frame 8 instead of on the reticle surface plate 3. When the stator 20 is provided on the reaction frame 8, the air bearing 19 is omitted, the stator 20 is fixed to the reaction frame 8, and the reaction force acting on the stator 20 due to the movement of the reticle coarse movement stage 16 is reacted. You may escape to the floor via the frame 8.

The reticle coarse movement stage 16 is guided in the Y-axis direction by a pair of Y guides 51 fixed to the upper surface of an upper protruding portion 3b formed in the center of the reticle surface plate 3 and extending in the Y-axis direction. It has become. The reticle coarse movement stage 16 is supported by the Y guides 51 and 51 by an air bearing (not shown) in a non-contact manner.

The reticle R is suction-held on the reticle fine movement stage 18 via a vacuum chuck (not shown). -Y of reticle fine movement stage 18
A pair of Y moving mirrors 52a and 52b formed of corner cubes are fixed to the ends in the direction, and an X moving mirror formed of a plane mirror extending in the Y axis direction is provided to the + X direction end of the reticle fine movement stage 18. 53 is fixed. Then, three laser interferometers (here, only the laser interferometer 67 is shown) for irradiating the movable mirrors 52a, 52b, and 53 with a measurement beam are provided with the reflecting surface of each movable mirror and the projection optical system P
Irradiating the laser light toward the reference mirror 68 fixed to the upper end of the lens barrel of L, and measuring the relative displacement between the movable mirror and the reference mirror based on the interference between the reflected light and the incident light. Thus, the position of the reticle stage 2 (and thus the reticle R) in the X, Y, and θZ (rotation around the Z axis) direction is measured in real time with a predetermined resolution, for example, a resolution of about 0.5 to 1 nm. The reticle fine movement stage 18 is preferably made of a material having high rigidity and a low coefficient of thermal expansion, and a metal, cordierite, or ceramics made of SiC can be used.

Returning to FIG. 1, as the projection optical system PL, here, both the object plane (reticle R) side and the image plane (wafer W) side are telecentric and have a circular projection field. A refraction optical system having a 1/4 (or 1/5) reduction magnification composed of a refraction optical element (lens element) made of a glass material is used. For this reason, when the reticle R is irradiated with the illumination light, the imaging light flux from the portion of the circuit pattern on the reticle R illuminated with the illumination light is transmitted to the projection optical system PL via the optical system 69 (described later). The light enters, and a partial inverted image of the circuit pattern is formed in a slit shape at the center of the circular field on the image plane side of the projection optical system PL and is formed. As a result, the projected partial inverted image of the circuit pattern is reduced and transferred to the resist layer on the surface of one of the plurality of shot regions on the wafer W arranged on the imaging plane of the projection optical system PL. .

An optical system 69 is provided between the projection optical system PL and the reticle R to irradiate the reticle R and transmit the exposure light as a telecentric parallel light beam to the projection optical system PL. Optical system (for example, glass) 69
Is supported by the lens barrel of the projection optical system PL via an elastic member 71 having a small spring constant such as a leaf spring or a coil spring. Outside the exposure light transmitting area of the optical system 69, three accelerometers (measuring devices) 72 (only two are shown in FIG. 1)
Are located. The accelerometer 72 measures the acceleration acting on the optical system 69, and thereby the optical system 69 and the projection optical system P are measured.
L, which measures the relative inclination (relative positional relationship) with respect to L. The measurement result is the main control device 7 as an adjusting device.
0 (see FIG. 6).

On the other hand, a flange 23 integrated with the lens barrel is provided on the outer periphery of the lens barrel of the projection optical system PL. The projection optical system PL is mounted on a lens barrel base 25 made of a casting or the like substantially horizontally supported on the stepped portion 8b of the reaction frame 8 via an anti-vibration unit 24 with the optical axis direction being the Z direction. And the flange 23 is engaged. The lens barrel base 25 may be made of a ceramic material having high rigidity and low thermal expansion.

The material of the flange 23 is a material having a low thermal expansion, for example, Invar (nickel 36%,
(A low-expansion alloy composed of 0.25% of manganese and iron containing trace amounts of carbon and other elements). The flange 23 constitutes a so-called kinematic support mount that supports the projection optical system PL at three points with respect to the barrel base 25 via points, surfaces, and V-grooves. When such a kinematic support structure is employed, it is easy to assemble the projection optical system PL to the lens barrel base 25, and it is caused by vibrations, temperature changes, and the like of the assembled lens barrel base 25 and the projection optical system PL. There is an advantage that stress can be reduced most effectively.

The anti-vibration unit 24 is disposed at each corner of the lens barrel base 25 (the anti-vibration unit at the back of the drawing is not shown), and an air mount 26 whose internal pressure can be adjusted.
A voice coil motor 27 for applying a thrust to the lens barrel base 25 is arranged in series on the step 8b. These vibration isolation units 24 insulate, at the micro G level, minute vibrations transmitted to the lens barrel base 25 (and the projection optical system PL) via the base plate 10 and the reaction frame 8.

A plurality of (for example, 3)
In FIG. 1, only one accelerometer 73 is provided as a detecting device for detecting a relative speed with respect to the wafer surface plate 6. The measurement result of the accelerometer 73 is output to a main controller 70 as a drive controller of the wafer stage 5 (see FIG. 6). The main controller 70 controls the vibration with respect to the projection optical system PL by driving the anti-vibration unit 24 based on the output of the accelerometer 73, the details of which will be described later.

As is apparent from FIG. 1, the stage device 7 is provided on the base plate 10 separately from the stage device 4 and the projection optical system PL. Stage device 7
A wafer stage 5, a wafer surface plate 6 for supporting the wafer stage 5 so as to be movable in a two-dimensional direction along the XY plane, a sample stage ST provided integrally with the wafer stage 5 and holding a wafer W by suction. X guide bar XG for supporting wafer stage 5 and sample stage ST movably relative to each other
It is mainly configured. A plurality of air bearings (air pads) 28, which are non-contact bearings, are fixed to the bottom surface of the wafer stage 5, and the air bearings 28 allow the wafer stage 5 to be placed on the wafer base 6 with a clearance of, for example, about several microns. It is supported floating through.

The wafer surface plate 6 is supported substantially horizontally above the base plate 10 via an anti-vibration unit 29. The anti-vibration units 29 are arranged at each corner of the wafer base 6 (the anti-vibration units on the back side of the drawing are not shown), and the thrust is applied to the air mount 30 and the wafer base 6 whose internal pressure is adjustable. And a voice coil motor (thrust applying device) 31 for applying the force is arranged in parallel on the base plate 10. These anti-vibration units 2
9, the wafer surface plate 6 through the base plate 10.
Is insulated at the micro G level. The base plate 10 of the wafer surface plate 6
The position relative to (floor) is detected by the position sensor 78 and output to the main control system 70 (see FIG. 6).

A plurality of (for example, 3
In FIG. 1, only one accelerometer 74 is used to detect a relative speed with respect to the lens barrel base 25 (projection optical system PL), and to detect vibration characteristics of the wafer base 6. It is provided as a detection device. The measurement result of the accelerometer 74 is output to a main controller 70 as a drive controller of the wafer stage 5 (see FIG. 6). Main controller 70
Controls the vibration of the projection optical system PL by driving the anti-vibration unit 29 based on the output of the accelerometer 74, the details of which will be described later.

As shown in FIG. 5, the X guide bar XG is
It has a long shape along the X direction, and movers 36, 36 each composed of an armature unit are provided at both ends in the length direction. The stators 37, 37 having magnet units corresponding to the movers 36, 36 are provided on support portions 32, 32 protruding from the base plate 10 (see FIG. 1, and in FIG. 1, the mover 36). And the stator 37 is shown in a simplified manner). The moving coil 36 and the stator 37 constitute moving coil linear motors 33, 33.
Is driven by electromagnetic interaction with the stator 37, the X guide bar XG moves in the Y direction, and the drive of the linear motors 33, 33 is adjusted so that θ
Rotate in the Z direction. That is, this linear motor 3
3, the wafer stage 5 (and the sample stage ST, hereinafter simply referred to as the wafer stage 5) almost integrally with the X guide bar XG.
) Are driven in the Y direction and the θZ direction. Although the wafer stage 5 is a guideless stage having no guide member for the movement in the Y direction, the guide stage can be appropriately formed for the movement of the wafer stage 5 in the X direction.

The wafer stage 5 is non-movably movable in the X direction relative to the X guide bar XG via a magnetic guide including a magnet and an actuator that maintains a predetermined gap in the Z direction between the wafer stage 5 and the X guide bar XG. Supported and held in contact. Further, the wafer stage 5 is driven in the X direction by electromagnetic interaction by an X linear motor 35 having a stator 35a embedded in the X guide bar XG. The mover of the X linear motor is not shown, but is attached to the wafer stage 5.

A wafer W is fixed on the upper surface of the wafer stage 5 via a wafer holder 41 by vacuum suction or the like (see FIG. 1, not shown in FIG. 5). Further, the position of wafer stage 5 in the X direction measures a change in position of movable mirror 43 fixed to a part of wafer stage 5 with reference to reference mirror 42 fixed to the lower end of the barrel of projection optical system PL. A predetermined resolution, for example, 0.5 to 1 by the laser interferometer 44
It is measured in real time with a resolution of about nm. In addition,
The position of the wafer stage 5 in the Y direction is set by a reference mirror, a laser interferometer, and a movable mirror 48 (see FIG. 5), which are arranged substantially perpendicular to the reference mirror 42, the movable mirror 43, and the laser interferometer 44. Measured. At least one of these laser interferometers is a multi-axis interferometer having two or more measurement axes. Based on the measurement values of these laser interferometers, only the XY position of the wafer stage 5 (and thus the wafer W) is determined. Instead, the θ rotation amount or the leveling amount can be obtained in addition to the θ rotation amount.

On the -X direction side of the X guide bar XG, a mover 34a of an X trim motor (reaction transmitting device) 34 constituted by a voice coil motor is mounted. The X trim motor 34 is interposed between the X guide bar XG as a stator of the X linear motor 35 and the reaction frame 8, and the stator 34 b is provided on the reaction frame 8. For this reason, the reaction force when driving the wafer stage 5 in the X direction is reduced by the X trim motor 3.
4 and transmitted to the reaction frame 8, and further transmitted to the base plate 10 via the reaction frame 8.

Further, on the flange 23 of the projection optical system PL, three laser interferometers 45 are fixed at three different places as detection devices for detecting the relative position of the wafer surface plate 6 in the Z direction. (However, one of these laser interferometers is typically shown in FIG. 1).
Openings 25a are respectively formed in portions of the lens barrel base 25 facing each of the laser interferometers 45, and a laser beam (length measuring beam) in the Z direction is transmitted from each of the laser interferometers 45 through these openings 25a. Is irradiated toward the wafer surface plate 6. A reflection surface is formed on the upper surface of the wafer surface plate 6 at a position facing each measurement beam. Therefore, the three laser interferometers 45 measure three different Z positions of the wafer surface plate 6 with reference to the flange 23 (however, in FIG. 1, the center of the wafer W on the wafer stage 5 is located at the center). Since the shot area is shown immediately below the optical axis of the projection optical system PL, the measurement beam is blocked by the wafer stage 5). Note that an interferometer that forms a reflection surface on the upper surface of the wafer stage 5 and measures three different Z-direction positions on the reflection surface with reference to the projection optical system PL or the flange 23 may be provided.

As described above, the reticle surface plate 3,
The lens barrel base 25 and the wafer base 6 each have a Z of each base.
Three accelerometers 75, 73, 74 for measuring vibration in the direction
Are installed as a group of vibration sensors,
Each surface plate is provided with three vibration sensors (for example, an accelerometer; not shown) for measuring vibrations in the XY plane. Two of these vibration sensors measure the vibration of each surface plate in the Y direction, and the remaining vibration sensors measure the vibration in the X direction (hereinafter, these vibration sensors are referred to as a vibration sensor group 77 for convenience). ; See FIG. 6). Then, based on the measurement values of these accelerometers 73 to 75 and vibration sensor group 77, main controller 70 controls reticle surface plate 3,
Six degrees of freedom of the wafer surface plate 6 and the lens barrel surface plate 25 (X, Y, Z,
θX, θY, θZ).

FIG. 6 shows a control system of the exposure apparatus 1. As shown in this figure, a position sensor, an accelerometer, a vibration sensor group,
The measurement results of various measuring devices of the laser interferometer are stored in the main controller 7
Output to 0. The main controller 70 performs various arithmetic processing based on the measurement results of these measuring devices, and based on the results, a reticle driving linear motor, a wafer driving linear motor, a wafer driving trim motor, a movable reticle blind driving It controls actuators, vibration isolation units, etc. In addition, the main controller 70 is provided with a storage device 76 for storing the vibration pattern (vibration characteristics) of the wafer surface plate 6 as a map.

Next, the operation of the exposure processing performed by the stage apparatus and the exposure apparatus configured as described above will be described. First, prior to the exposure processing, vibration characteristics of the wafer surface plate 6 according to the position of the wafer stage 5 are determined, and
The position of the center of gravity of the stage device 7 corresponding to the position of the wafer stage 5 and the principal axis of inertia are determined. In order to obtain the vibration characteristics of the wafer surface plate 6, the wafer stage 5 is moved, for example, near the -X side end portion, near the center portion, and near the + X side end portion on the wafer surface plate 6 (in FIG. 1, right side, center, left side, respectively). ). Then, the wafer stage 5 is moved at that position, and the vibration accompanying this movement is detected by the accelerometer 74 and the vibration sensor group 77 and stored in the storage device 76.

FIG. 7 shows the acceleration output of the rotational direction component detected at this time. FIG. 7A shows the −X of the wafer surface plate 6.
(B) is the acceleration output detected at the center, and (c) is the acceleration output detected at the + X side. Main controller 70 sets a map of an acceleration output pattern (thrust pattern) that cancels (attenuates) the obtained acceleration output pattern and a correction coefficient corresponding to the position of wafer stage 5 and stores them in storage device 76. . The movement pattern of the wafer stage 5 when setting the map is the same as the process performed during actual exposure.

To determine the position of the center of gravity and the principal axis of inertia in the stage device 7, the wafer stage 5 must be
Stop at the respective positions near the X-side end, near the center, and near the + X-side end. For example, the main control unit 70 drives the voice coil motor 31 of the vibration isolation unit 29 to generate an impulse waveform on the wafer surface plate 6. Gives a dummy vibration. Main controller 70 executes a predetermined calculation sequence based on the result of detection of this vibration by vibration sensor group 77 and accelerometer 74, whereby the inertial system of stage device 7 according to the position of wafer stage 5 The position of the center of gravity and the principal axis of inertia can be determined and identified. Then, by the above-described identification processing, the position of the center of gravity P and the principal axes of inertia ζ, η, and ξ can be obtained. The vibration on the wafer surface plate 6 may be performed by driving the wafer stage 5 instead of driving the voice coil motor. In addition, the measurement positions of the wafer stage 5 can be obtained at any positions other than the above three positions.

After obtaining the thrust map, the position of the center of gravity, and the principal axis of inertia of the inertial system, the exposure processing is performed. Here, it is assumed that various exposure conditions for scanning and exposing a shot area on the wafer W with an appropriate exposure amount (target exposure amount) are set in advance. Preparatory operations such as reticle alignment and baseline measurement using a reticle microscope and an off-axis alignment sensor (not shown) are performed, and then fine alignment (EGA;
(Enhanced global alignment, etc.) is completed, and the arrangement coordinates of a plurality of shot areas on the wafer W are obtained.

When the preparation operation for exposure of the wafer W is completed as described above, the linear motors 33 and 35 are controlled to monitor the measurement value of the laser interferometer 44 on the basis of the alignment result, thereby controlling the wafer W. The wafer stage 5 is moved to a scanning start position for the exposure of the first shot. Then, the reticle stage 2 and the wafer stage 5 start scanning in the Y direction via the linear motors 15 and 33, and when both stages 2 and 5 reach their respective target scanning speeds,
Illumination optical system I set by movable reticle blind 62
A predetermined rectangular illumination area on the reticle R is illuminated with uniform illuminance by the exposure illumination light from U. In synchronization with the reticle R being scanned in the Y direction with respect to this illumination area, the wafer W is scanned with respect to an exposure area conjugate with respect to this illumination area and the projection optical system PL.

Here, in the movable reticle blind 62, the movable blade is moved to block the illumination light when exposure is not performed, such as before exposure, so that both the stages 2, 5, ie, the reticle R and the wafer W are moved. When the exposure is performed after reaching the exposure position, an opening is formed and a predetermined illumination area is set. As a result, the illumination light emitted from the light source LS illuminates the reticle R in a rectangular area set by the opening of the movable blade.

Then, the illumination light transmitted through the pattern area of the reticle R is reduced by a factor of 4 by the projection optical system PL, and is irradiated onto the resist-coated wafer W. Then, the pattern of the reticle R is sequentially transferred to the exposure area on the wafer W, and the entire pattern area on the reticle R is transferred to the shot area on the wafer W by one scan. During this scanning exposure, the moving speed of the reticle stage 2 in the Y direction and the moving speed of the wafer stage 5 in the Y direction are determined by the projection magnification (1/5 or 1/4) of the projection optical system PL.
The reticle stage 2 and the wafer stage 5 are synchronously controlled via the linear motors 15 and 33 so as to maintain the speed ratio according to (times).

The reaction force at the time of acceleration / deceleration of the reticle stage 2 in the scanning direction is absorbed by the movement of the stator 20, and the position of the center of gravity of the stage device 4 is substantially fixed in the Y direction. Further, the reticle surface plate is not used because the friction between the reticle stage 2, the stator 20, and the reticle surface plate 3 is not zero or the moving direction between the reticle stage 2 and the stator 20 is slightly different. Even when a minute vibration in the direction of 3-6 degrees of freedom remains, feedback control of the air mount 12 and the voice coil motor 13 is performed based on the measurement values of the vibration sensor group 77 and the accelerometer 75 so as to eliminate the residual vibration. I do.

In the lens barrel base 25, even if a slight vibration occurs due to the movement of the reticle stage 2 and the wafer stage 5, the main controller 70 controls the vibration sensor group 77 provided on the lens barrel base 25, 6 based on the measurement value of the accelerometer 73
By obtaining the vibration in the direction of the degree of freedom and performing feedback control of the air mount 26 and the voice coil motor 27, this minute vibration can be canceled, and the lens barrel base 25 can be constantly maintained at a stable position.

Similarly, in the stage device 7, the main controller 70 controls the anti-vibration unit 29 based on the measurement value of the laser interferometer 44 or the like to cancel the influence of the change in the center of gravity due to the movement of the wafer stage 5. , And the air mount 30 and the voice coil motor 31 are driven so as to generate this force. Further, even when a slight vibration of the wafer base 6 in the direction of six degrees of freedom remains due to the fact that the friction between the wafer stage 5 and the wafer base 6 is not zero, the vibration sensor group 77 and the accelerometer 74 Based on the measured value, the air mount 30 and the voice coil motor 31 are feedback-controlled to eliminate the residual vibration. This voice coil motor 31
The main controller 70 drives the voice coil motor 31 by converting the center of gravity corresponding to the position of the wafer stage 5 detected in advance and the thrust in the coordinate system of the inertia main axis of the inertia system. As a result, an appropriate thrust in the coordinate system of the true inertia main axis is applied to the wafer surface plate 6 instead of the design value, and more accurate and effective vibration suppression can be performed.

Further, when driving voice coil motor 31, main controller 70 compares wafer output table 6 with the map of the acceleration output pattern stored in storage device 76.
Is corrected by a correction coefficient in accordance with the position of the wafer stage 6 in the step (1), and the voice coil motor 31 is driven based on the corrected map. If there is still residual vibration even after driving the voice coil motor 31, a correction coefficient is set so as to attenuate the residual vibration, and the thrust based on the map is driven to drive the voice coil motor 31. FIG. 9 shows a control loop at this time. As described above, since the thrust of the voice coil motor 31 in the stage device 7 is output as a thrust command value in a feedforward manner using the map and the correction coefficient detected in advance, the residual vibration is effectively attenuated in a short time. it can.

The map of the acceleration output pattern does not necessarily need to be created before the exposure processing. If the map is created based on the driving of the wafer stage 5 in the actual machine, the map is created during the processing and updated at any time. May be configured. For example, when an acceleration output indicated by a two-dot chain line in FIG. 7A is obtained during the exposure processing, the map may be corrected using the output difference ε. In addition, thrust adjustment using a map has been described for the stage device 7 (wafer surface plate 6), but a map is created in advance for the reticle surface plate 3 and the lens barrel surface plate 25, and the map, the correction coefficient, , The thrust of the voice coil motor can be adjusted according to the position of the reticle stage 2 or the wafer stage 5.

Further, the vibration control and the exposure processing control accompanying the stage movement will be described in detail. The movement of the reticle stage 2 and the wafer stage 5 may cause the reaction frame 8 to vibrate. In particular, since the reaction force accompanying the movement of the wafer stage 5 in the X direction is transmitted to the reaction frame 8 via the X trim motor 34, the residual illumination of the reaction frame 8 causes the second illumination optical system via the support column 9. There is a possibility that the IU2 vibrates (relatively moves) with respect to the first illumination optical system IU1. When the movable reticle blind 62 is driven via the actuator 63 for setting an illumination area on the reticle R, the first illumination optical system IU1 is transmitted to the second illumination optical system IU2 due to the vibration generated by the driving. Vibration (relative movement) may occur.

At this time, main controller 70 controls actuator 6 according to the relative distance between movable reticle blind 62 detected by position sensor 66 and second illumination optical system IU2.
The movable blade is moved in each of the X direction and the Y direction via 3. Thereby, the first illumination optical system I
Even when vibration occurs such that the U1 and the second illumination optical system IU2 move relatively, the relative positional relationship between the movable reticle blind 62 and the second illumination optical system IU2, that is, the illumination area for the reticle R does not change. It is kept in place. Note that an actuator for moving the movable reticle blind 62 in the Z direction may be provided to correct the relative positional relationship in the Z direction.

Also, due to the slight vibration of the projection optical system PL, etc.
The optical system 69 may be tilted with respect to (the optical axis of) the projection optical system PL. In this case, the exposure light transmitted through the reticle R is transmitted through the optical system 69, and is incident as a parallel light beam inclined with respect to the optical axis of the projection optical system PL according to the inclination of the optical system 69. As a result, the pattern image of the reticle R is formed on the wafer W at a position shifted from a predetermined position. Therefore, main controller 70 calculates the shift amount of the pattern formed on wafer W from the relative inclination between optical system 69 and projection optical system PL measured by accelerometer 72, and corrects this shift amount. Reticle stage 2 is driven. Specifically, an offset value corresponding to the shift amount is given to the drive amount for reticle stage 2. Thereby, the position of the pattern image formed on the wafer W is corrected to the predetermined position. As a means for measuring the relative positional relationship between the optical system 69 and the projection optical system PL, a measuring device for measuring a relative distance, such as a laser interferometer, may be used in addition to the accelerometer. In addition, in order to correct the shift amount of the pattern formed on the wafer W, the drive amount of the reticle stage 2 has an offset value in addition to the drive amount of the reticle stage 2 and the offset value corresponding to the shift amount. You may have it.

Further, regarding the above scanning exposure, the lens barrel surface plate 2
5 and the wafer surface plate 6, that is, the projection optical system PL and the wafer W are made to follow by the speed control system. This control loop is shown in FIG. In this figure, reference numeral S1 denotes a projection optical system PL (that is, a lens barrel base 25 and an anti-vibration unit 24).
Reference numeral S2 denotes a control loop (control system) related to the wafer W (that is, the wafer surface plate 6, the anti-vibration unit 29). The two-dot chain line in the control system S1 is a plant part showing the lens barrel base 25 and the vibration isolation unit 24, and the two-dot chain line in the control system S2 is a plant part showing the wafer surface plate 6 and the vibration isolation unit 29. It is.

As shown in this figure, the control system S1 includes a speed control loop S for forming a speed servo based on a speed obtained by integrating (calculating) the acceleration detected by the accelerometer 73.
A cascaded control system is provided in which R1 is a minor loop, and a position control loop PR1 that controls the speed control loop SR1 based on the measurement result of the position sensor 78 is a main loop. Similarly, the control system S2 includes the accelerometer 7
A speed control loop SR2 for forming a speed servo based on a speed obtained by integrating the acceleration detected in step 4 is a minor loop, and a position control loop PR2 for controlling the speed control loop SR2 based on the measurement result of the laser interferometer 45 is a main loop. It is composed of a cascade control system that forms a loop. In the speed control loop, mainly 10 to 20 Hz
In the position control loop, vibration in a low frequency region of, for example, about 0.1 Hz is suppressed.

In this embodiment, the acceleration in the speed control loop SR1 in the control system S1 is output to the speed control loop SR2 in the control system S2. In the control system S2, speed servo is performed based on the difference between the acceleration of the wafer surface plate 6 and the acceleration of the lens barrel surface plate 25, that is, the relative speed obtained by integrating the relative acceleration. As a result, the wafer surface plate 6 is driven to follow the lens barrel surface plate 25 under speed control. In other words, the wafer W is driven synchronously so as to follow the projection optical system PL.

As a method for detecting the relative speed between the projection optical system PL and the wafer W, a laser for detecting the relative distance between the projection optical system PL and the wafer base 6 without using the accelerometers 73 and 74 is used. It can also be obtained by differentiating (calculating) the detection result of the interferometer 45. FIG. 11 shows a control loop at this time. As shown in this figure, the control system S2
In, the speed control can be performed based on the relative speed obtained by differentiating the relative distance detected by the laser interferometer 45.

As described above, in the stage apparatus and the exposure apparatus of the present embodiment, the acceleration applied to the barrel base 25 and the acceleration applied to the wafer base 6, that is, the acceleration applied to the projection optical system PL and the acceleration applied to the wafer W Speed control is performed based on the relative speeds detected based on the applied acceleration and the wafer W is made to follow the projection optical system PL in the optical axis direction. Therefore, even when the projection optical system PL vibrates for some reason, the projection optical system The system PL and the wafer W can be synchronized in the optical axis direction, and their relative positional relationship can be maintained. Therefore, even when the pattern on the reticle R is formed on the wafer W by exposure, the projection optical system P
The focal position of L is set to a predetermined position of wafer W (resist coated surface)
, And it is possible to prevent the occurrence of image blur or the like, thereby improving the exposure accuracy. The same effect can be obtained when the relative speed is obtained by differentiating the relative distance between the projection optical system PL and the wafer surface plate 6 obtained from the measurement result of the laser interference system 45.

In the vibration damping method of the stage device according to the present embodiment, the position of the center of gravity and the principal axis of inertia when the wafer surface plate 6 is vibrated are obtained, and are applied to the surface plate based on the position of the center of gravity and the principal axis of inertia. Since the thrust is corrected, an appropriate thrust according to the true inertial system can be given, and accurate and effective vibration suppression (short-time vibration damping) can be performed. In addition, even if vibration control is performed by obtaining the position of the center of gravity of the apparatus and the principal axis of inertia by simulation, accurate vibration suppression can be performed in the same manner as described above. Since the position of the center of gravity and the main axis of inertia are determined by applying vibration to the surface plate 6, more accurate vibration suppression is possible.

In the present embodiment, the position of the center of gravity and the principal axis of inertia are detected in accordance with the position of wafer stage 5 with respect to wafer surface plate 6, respectively.
Is moved by scanning or stepping,
The thrust to be applied to the wafer surface plate 6 can be obtained by converting the thrust applied to the wafer center plate 6 into a coordinate system of an accurate center of gravity and a principal axis of inertia.
More accurate and effective vibration suppression can be performed. The direction in which the thrust is applied to the wafer surface plate 6 may be a direction toward the center of gravity, in addition to the direction along the Z direction. In this case, since no rotational moment is generated when the thrust is applied, more stable vibration suppression can be performed in a short time.

Further, in this embodiment, the wafer surface plate 6
Is stored in advance as a map, and the thrust of the voice coil motor 31 in the stage device 7 is output as a thrust command value by feedforward using the map and a correction coefficient corresponding to the position of the wafer stage 5. So that the residual vibration can be effectively attenuated,
The time required for settling can be shortened. Moreover, since this map is obtained by driving the wafer stage 5 in the actual machine, there is no need to consider a correction term as in the case of calculation or experiment, and a more accurate vibration characteristic according to the actual machine is stored. can do.

In this embodiment, since the movable reticle blind 62 is arranged independently of the reaction frame 8 in terms of vibration, vibration caused by driving of the blade is transmitted through the reaction frame 8 to the projection optical system PL or the reticle. R and the wafer W can be prevented, and the displacement of the pattern transfer position and the occurrence of image blur due to these vibrations can be effectively prevented, and the exposure accuracy can be improved. Further, the first illumination optical system IU1 and the second illumination optical system IU2 are caused by vibration accompanying the driving of the reticle stage 2 and the wafer stage 5 and vibration accompanying the driving of the movable reticle blind 62.
However, in the present embodiment, the movable reticle blind 62 and the second illumination optical system I
Since the movable blade is moved in each of the X direction and the Y direction in accordance with the relative distance to U2, the illumination area with respect to reticle R can be maintained at a predetermined position, and the pattern formed on wafer W by exposure is formed. It is possible to prevent a decrease in positional accuracy and overlay accuracy beforehand. Further, in the present embodiment, since the position of the movable blade is adjusted within a two-dimensional plane, the first illumination optical system IU1 and the second illumination optical system IU1 are adjusted.
It is possible to cope with the case where the relative movement with the illumination optical system IU2 occurs two-dimensionally.

Further, in the present embodiment, the shift amount of the pattern formed on the wafer W is calculated from the relative inclination of the optical system 69 and the projection optical system PL, and the reticle is corrected so as to correct the shift amount. Since the drive amount of the stage 2 is corrected, it is possible to prevent a pattern position shift on the wafer W due to a position error of the optical system 69, which can contribute to an improvement in exposure accuracy.

In the above embodiment, the voice coil motor is used as the X trim motor 34 for transmitting the reaction force applied to the X guide bar XG to the reaction frame 8 as the wafer stage 5 moves. The present invention is not limited to this configuration.
An EI core may be provided by coupling with the mold core. In this case, one of the E-shaped core and the I-shaped core is connected to the X guide bar XG.
Side, and the other side may be disposed on the reaction frame 8 side, and any of a moving coil type and a moving magnet type can be applied. The moving magnet type eliminates the need for wiring for the moving X guide bar XG, thereby simplifying the device configuration and eliminating the adverse effects of vibration transmitted through the wiring. In the case of the moving coil type, since the area for energizing the coil is small, the influence of heat generated by energization can be suppressed.

The EI core can output about 1.5 times as much thrust as the voice coil motor. Therefore, by providing an EI core as the X trim motor 34, the size of the voice coil motor that outputs the same thrust can be about ／, and the size of the apparatus can be reduced. In particular, the reaction force applied to the X guide bar XG is 1000
N, the difference in magnitude greatly contributes to miniaturization of the entire device as a motor that outputs a thrust capable of transmitting the reaction force.

Since the X trim motor 34 adjusts the position P of the X guide bar XG in the X direction, it is necessary to strictly control the relative position between the E type core and the I type core in the EI core. There is. Here, in order for the EI core to output a sufficient thrust, it is necessary to regulate the relative position between the E-shaped core and the I-shaped core within a predetermined range. It is desirable to provide. In this case, main controller 70 can maintain the relative position within a predetermined range by controlling the bias current based on the measured relative position between the E-type core and the I-type core. As a result, a thrust sufficient to counter the reaction force applied to the X guide bar XG can always be output.

In the above embodiment, the stage apparatus of the present invention is applied to the exposure apparatus 1. However, the present invention is not limited to this. The present invention is also applicable to precision measuring devices such as a pattern position coordinate measuring device. Further, in the above embodiment, the linear motors 15 and 33 are of the moving coil type, but it is needless to say that they may be of the moving magnet type.

The substrate of the present embodiment is not limited to a semiconductor wafer W for a semiconductor device, but also a glass substrate for a liquid crystal display device, a ceramic wafer for a thin-film magnetic head, or a mask or a mask used in an exposure apparatus. Reticle master (synthetic quartz, silicon wafer)
Etc. are applied.

The exposure apparatus 1 includes a step-and-scan type scanning exposure apparatus (scanning stepper; US Pat. No. 5,473,410) for scanning and exposing the pattern of the reticle R by synchronously moving the reticle R and the wafer W. To
The present invention is also applicable to a step-and-repeat type projection exposure apparatus (stepper) that exposes the pattern of the reticle R while the reticle R and the wafer W are stationary and sequentially moves the wafer W stepwise.

The type of the exposure apparatus 1 is not limited to an exposure apparatus for manufacturing a semiconductor device for exposing a semiconductor device pattern onto a wafer W, but may be an exposure apparatus for manufacturing a liquid crystal display element, a thin film magnetic head, an image pickup device (CCD). Alternatively, the present invention can be widely applied to an exposure apparatus for manufacturing a reticle and the like.

As the light source of the illumination light for exposure, a bright line (g-line (436 nm), h
Line (404.7 nm), i-line (365 nm)), KrF
Not only an excimer laser (248 nm), an ArF excimer laser (193 nm), and an F ₂ laser (157 nm) but also a charged particle beam such as an X-ray or an electron beam can be used. For example, when an electron beam is used, a thermionic emission type lanthanum hexaborite (LaB ₆ ) or tantalum (Ta) can be used as an electron gun. When an electron beam is used, a configuration using a reticle R may be used, or a configuration may be used in which a pattern is directly formed on a wafer without using the reticle R. Alternatively, a high frequency such as a YAG laser or a semiconductor laser may be used.

The magnification of the projection optical system PL may be not only a reduction system but also any one of an equal magnification system and an enlargement system. Further, As the projection optical system PL, using a material which transmits far ultraviolet rays such as quartz and fluorite as the glass material when using a far ultraviolet ray such as an excimer laser, catadioptric system, or in the case of using the F ₂ laser or X-ray An optical system of a refraction system (a reticle R of a reflection type is also used). When an electron beam is used, an electron optical system including an electron lens and a deflector may be used as the optical system. It is needless to say that the optical path through which the electron beam passes is in a vacuum state. Further, the present invention can also be applied to a proximity exposure apparatus that exposes the pattern of the reticle R by bringing the reticle R and the wafer W into close contact without using the projection optical system PL.

A linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is mounted on the wafer stage 5 and the reticle stage 2.
Is used, any of an air levitation type using an air bearing and a magnetic levitation type using Lorentz force or reactance force may be used. In addition, each stage 2, 5
May be a type that moves along a guide or a guideless type that does not have a guide.

As a driving mechanism of each of the stages 2 and 5, a magnet unit (permanent magnet) having a two-dimensionally arranged magnet and an armature unit having a two-dimensionally arranged coil are opposed to each other, and each stage 2 and 5 is driven by electromagnetic force. 5 may be used. In this case, one of the magnet unit and the armature unit may be connected to the stages 2 and 5, and the other of the magnet unit and the armature unit may be provided on the moving surface side (base) of the stages 2 and 5.

As described above, the exposure apparatus 1 of the present embodiment is
Is a system that includes various components including the components listed in the claims of the present application, with predetermined mechanical accuracy, electrical accuracy,
It is manufactured by assembling to maintain optical accuracy. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

The semiconductor device, as shown in FIG.
Step 201 for designing the function and performance of the device, step 202 for manufacturing a mask (reticle) based on this design step, step 203 for manufacturing a wafer from a silicon material, and the pattern of the reticle by the exposure apparatus 1 of the above-described embodiment. Wafer processing step 204 for exposing a wafer, device assembling step (including dicing step, bonding step, package step) 20
5. It is manufactured through an inspection step 206 and the like.

[0100]

As described above, according to the first aspect of the present invention, a vibration control method for a stage device is provided to a surface plate based on the position of the center of gravity detected when the surface plate is vibrated and the principal axis of inertia. The procedure is to correct thrust. As a result, according to the vibration damping method of the stage device, it is possible to apply an appropriate thrust according to a true inertial system instead of a design value, and to obtain an effect that accurate vibration damping can be performed in a short time.

In the vibration control method for a stage device according to the second aspect, the stage body is driven to vibrate the surface plate. As a result, in this method of controlling the vibration of the stage device, it is possible to apply an appropriate thrust according to the true inertial system at the time of driving the stage body, instead of the design value, and more accurate vibration control in a short time. The effect that it can be implemented is obtained.

The third aspect of the present invention provides a vibration control method for a stage apparatus, which comprises detecting a center of gravity position and an inertia main axis corresponding to a position of a stage main body with respect to a surface plate. As a result, according to the vibration damping method of the stage device, even if the position of the center of gravity and the main axis of inertia move with the movement of the stage body, more accurate and effective vibration damping can be achieved each time.

The stage device according to claim 4 is configured to correct the thrust applied to the surface plate based on the position of the center of gravity and the inertia main axis of the stage device when the surface plate is vibrated. As a result, in this stage device, it is possible to apply an appropriate thrust according to a true inertial system instead of a design value, and it is possible to obtain an effect that accurate vibration suppression can be performed in a short time.

The stage device according to claim 5 is configured such that thrust is applied toward the position of the center of gravity. Thus, in this stage device, there is an effect that a rotational moment is not generated at the time of applying a thrust, and more stable vibration suppression can be performed in a short time.

According to a sixth aspect of the present invention, in the stage device, the reaction force transmitting device for transmitting the reaction force generated on the stator to the support portion by the movement of the stage body has an EI core formed by coupling the E-type core and the I-type core. It has a configuration. As a result, in this stage device, an effect that the device can be downsized can be obtained.

The stage device according to claim 7 is configured to control the driving of the EI core based on the relative position between the E-shaped core and the I-shaped core. As a result, this stage device has an effect that a thrust sufficient to always oppose the reaction force applied to the stator can always be output.

The stage device according to claim 8 is configured to control the driving of the thrust applying device based on the vibration characteristics of the surface plate stored in accordance with the position of the stage body. Thus, in this stage device, the residual vibration can be effectively attenuated, and the time required for settling can be shortened.

The stage device according to the ninth aspect is configured to store the vibration characteristics of the surface plate when the stage main body is driven. As a result, in this stage device, there is no need to consider a correction term as in the case of calculation or experiment, and an effect that a more accurate vibration characteristic suitable for an actual machine can be stored.

An exposure apparatus according to a tenth aspect is configured such that the stage apparatus according to any one of the fourth to ninth aspects is used as at least one of the mask stage and the substrate stage. I have. Thus, in this exposure apparatus, even when the mask or the substrate is moved, the time required for settling is shortened, the production efficiency is improved, and the exposure accuracy is improved by accurate vibration suppression.

An exposure apparatus according to claim 11 drives at least the substrate to follow the projection optical system in the optical axis direction based on the relative speed between the projection optical system and the substrate in the direction of the optical axis of the projection optical system. It has become. Accordingly, in the exposure apparatus, since these relative positional relationships can be maintained, the focal position of the projection optical system can always be maintained at a predetermined position on the substrate, and the occurrence of image blur and the like can be effectively prevented. Thus, exposure accuracy can be improved.

The exposure apparatus according to the twelfth aspect is configured so that the relative velocity is detected by the detection apparatus calculating the acceleration applied to the projection optical system and the acceleration applied to the substrate. Thereby, in this exposure apparatus, even when the accelerometer is used,
The focus position of the projection optical system can always be maintained at a predetermined position on the substrate, and the occurrence of image blur and the like can be effectively prevented, and the exposure accuracy can be improved.

An exposure apparatus according to a thirteenth aspect has a configuration in which the detection device calculates the relative position between the projection optical system and the substrate in the optical axis direction to detect the relative speed. Thus, in this exposure apparatus, even when the relative position between the projection optical system and the substrate is detected by a laser interferometer or the like, the focus position of the projection optical system can always be maintained at a predetermined position on the substrate, Exposure can be improved by effectively preventing blurring or the like.

An exposure apparatus according to a fourteenth aspect is configured such that the detecting device detects the relative speed via the surface plate. Thus, in this exposure apparatus, the surface plate is almost stationary in the direction orthogonal to the optical axis, and has a large area compared to the substrate, so that the relative speed can be easily detected.

The exposure apparatus according to the fifteenth aspect is configured to be a scanning type exposure apparatus that scans a mask and a substrate to expose a pattern on the substrate. Thus, in this exposure apparatus, even when the mask and the substrate are scanned, the time required for settling is shortened, the production efficiency is improved, and the exposure accuracy is improved by accurate vibration suppression.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an exposure apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of an exposure apparatus in which a second illumination optical system is supported by a reaction frame.

FIG. 3 is a plan view of a movable reticle blind constituting an illumination optical system.

FIG. 4 is an external perspective view of a reticle stage included in the exposure apparatus.

FIG. 5 is an external perspective view of a wafer-side stage device constituting the exposure apparatus.

FIG. 6 is a control block diagram illustrating a control system of the exposure apparatus.

FIGS. 7A to 7C are diagrams respectively showing output trajectories of an accelerometer on a wafer surface plate.

FIG. 8 is a view for explaining the position of the center of gravity and the principal axis of inertia in the exposure apparatus.

FIG. 9 is a diagram showing a control loop of vibration control using a map.

FIG. 10 is a diagram showing a control loop for driving the projection optical system and the wafer to follow each other under speed control.

FIG. 11 is a diagram showing a control loop for driving the projection optical system and the wafer to follow each other under speed control.

FIG. 12 is a flowchart illustrating an example of a semiconductor device manufacturing process.

[Explanation of symbols]

IU illumination optical system IU1 first illumination optical system (illumination optical system) IU2 second illumination optical system (illumination optical system) PL projection optical system R reticle (mask) W wafer (substrate) 1 exposure apparatus 2 reticle stage (mask stage) Reference Signs List 5 wafer stage (substrate stage, stage body) 6 wafer surface plate (surface plate) 7 stage device 8 reaction frame (supporting part) 31 voice coil motor (thrust applying device) 34 X trim motor (reaction transmitting device) 35 X linear Motor (drive device) 35a Stator 45 Laser interferometer (detection device, relative speed detection device) 62 Reticle blind (illumination area setting device) 66 Position sensor (detection device, relative position detection device) 69 Optical system 70 Main control device ( Adjustment device, control device, correction device, drive control device) 72 Accelerometer (measuring device, relative tilt) Measuring device) 73 Accelerometer (detection device, relative speed detection device) 74 Accelerometer (detection device, relative speed detection device, vibration detection device) 76 Storage device

Claims (15)

[Claims] 1. A method for applying a thrust to a stage device having a stage main body driven on a surface plate to control vibration, wherein the stage device is vibrated when the surface plate is vibrated. Detecting the position of the center of gravity and the principal axis of inertia in step (a), and correcting the thrust based on the detected position of the center of gravity and the principal axis of inertia. 2. The vibration damping method for a stage device according to claim 1, wherein the surface plate is vibrated by driving the stage main body. 3. The vibration damping method for a stage device according to claim 1, wherein the position of the center of gravity corresponding to the position of the stage main body with respect to the surface plate and the principal axis of inertia are detected. Stage device vibration suppression method. 4. A stage body driven on a surface plate,
A stage device comprising: a thrust applying device that applies thrust to the surface plate, wherein the detection device detects a center of gravity position and an inertia main axis of the stage device when the surface plate is vibrated, A correction device for correcting a thrust applied to the surface plate based on a detection result of the device. 5. The stage device according to claim 4, wherein the thrust is applied toward the position of the center of gravity. 6. A stage device comprising a stage main body driven on a surface plate, comprising: a driving device having a stator and a mover for driving the stage main body; And a reaction force which is interposed between the support portion and the stator and transmits a reaction force generated on the stator by movement of the stage body to the support portion. A stage device comprising a transmission device, wherein the reaction force transmission device has an EI core formed by coupling an E-shaped core and an I-shaped core. 7. The stage device according to claim 6, wherein the measuring device measures a relative position between the E-shaped core and the I-shaped core, and controls driving of the EI core based on a measurement result of the measuring device. A stage device, comprising: 8. A stage body driven on a surface plate,
A stage device comprising: a thrust applying device that applies a thrust to the surface plate; a storage device that stores vibration characteristics of the surface plate according to a position of the stage main body; and detects vibration characteristics of the surface plate. A stage device comprising: a vibration detecting device that performs the driving, and a control device that controls driving of the thrust applying device based on a detection result of the vibration detecting device and a content stored in the storage device. 9. The stage device according to claim 8, wherein the storage device stores vibration characteristics of the surface plate when the stage body is driven. 10. An exposure apparatus for exposing a pattern of a mask held on a mask stage to a substrate held on a substrate stage, wherein at least one of the mask stage and the substrate stage is used. 10. An exposure apparatus, wherein the stage apparatus according to any one of 9 is used. 11. An exposure apparatus for projecting and exposing a pattern of a mask onto a substrate by a projection optical system, comprising: a detection device for detecting a relative speed between the projection optical system and the substrate in a direction substantially along an optical axis of the projection optical system; An exposure apparatus, comprising: a drive control device that drives at least the substrate to follow the projection optical system in the optical axis direction based on a detection result of the detection device. 12. The exposure apparatus according to claim 11, wherein the detection device calculates the acceleration applied to the projection optical system and the acceleration applied to the substrate to detect the relative speed. apparatus. 13. The exposure apparatus according to claim 11, wherein the detection device calculates the relative position between the projection optical system and the substrate in the optical axis direction to detect the relative speed. Exposure equipment. 14. The exposure apparatus according to claim 11, further comprising: a stage that holds and moves the substrate; and a surface plate that movably supports the stage. An exposure apparatus, wherein the detection device detects the relative speed via the surface plate. 15. The exposure apparatus according to claim 10, wherein the exposure apparatus scans the mask and the substrate to expose the pattern on the substrate. An exposure apparatus, comprising: