JP2001102279A - Stage device and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform high-precision position control, while avoiding the influence of vibration. SOLUTION: Devices are equipped with a stage main body 2 which holds a sample and moves, speed detection parts 54 to 56 which are provided to the stage main body 2 and detect information regarding the speed of the stage main body 2, and a speed control system which controls the moving speed of the stage main body 2 according to the detection results of the speed detection parts 54 to 56.

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 an exposure apparatus that performs an exposure process using a mask and a substrate held by the stage apparatus, particularly when manufacturing a device such as a semiconductor integrated circuit or a liquid crystal display,
The present invention relates to a stage apparatus and an exposure apparatus suitable for use in a lithography process.

[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 such as an air mount and a voice coil motor capable of controlling the internal pressure is provided as the vibration isolating table, and the actuator is attached to a main body column (main frame).
For example, an active vibration isolating table that controls the vibration of the main body column by controlling the voice coil motor and the like based on the measurement values of six accelerometers is employed.

The above-mentioned stepper or the like moves after exposure of a certain shot area on a wafer and sequentially repeats exposure of another shot area. A wafer stage (in the case of a stepper) or a reticle stage and a wafer The position of the stage (in the case of a scanning stepper) is measured and monitored by an optical interferometer such as a laser interferometer. The position control for these stages employs a speed control method because of its superior controllability as compared with a so-called position control method for performing feedback control of the measured position of the stage.

FIG. 7 shows a conventional control loop for the stage position by the speed control method. As shown in this figure, a function unit C1 such as a PID controller for a given target value moves the stage to a target position based on the positional deviation between the target value and the measurement result of the optical interferometer. Output the speed of Similarly, the function unit C2 such as a PID controller outputs the driving force of the stage based on the deviation between the speed obtained by differentiating the measurement result of the optical interferometer and the speed output from the function unit C1. Thereafter, in the control loop,
The position of the stage is controlled based on the speed deviation between the speed obtained based on the driving force and the speed obtained by differentiating the position information measured by the optical interferometer.

However, in this speed control method, since the stage speed is obtained by differentiating the position information measured by the optical interferometer, high frequency noise is included in the obtained value, which is difficult in accuracy. Was. Further, the speed information to be detected depends on the position detection resolution of the optical interferometer and the sampling time, so that the detection accuracy is limited. Therefore, at present, speed control is not performed, and the stage position is controlled by a position control method that feeds back the position of the stage.

[0009]

However, the conventional stage apparatus and exposure apparatus as described above have the following problems. In recent years, there has been an increasing demand for miniaturization of semiconductor devices and high-speed exposure processing. However, the reaction force generated by the movement of the stage (acceleration, constant velocity, deceleration) causes vibration of the main body column. As a result, a relative position error between the projection optical system and the wafer or the like may occur. The relative position error at the time of alignment or exposure may result in an image blur (increase in pattern line width) when a pattern is transferred to a position different from the design value on the wafer as a result, or when the position error includes a vibration component. May be caused.

Since each stage uses an air bearing as a guide for movement, relatively high frequency vibration of the main body column can be blocked by the air bearing.
However, even if the high frequency vibration component of the main body column can be canceled by the air bearing, there still exists a disadvantage that the fine vibration is still transmitted to the stage and the target position following error of the stage is deteriorated.

In order to suppress such inconvenience, for example, in the case of a stepper, an alignment operation or an exposure operation is started after the wafer stage is positioned at a desired position and sufficiently settled, or a scanning stepper is used. In such a case, 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, exposure is performed in a state where the synchronous setting of the reticle stage and the wafer stage is sufficiently ensured. However, in this case, it is not realistic because it causes a decrease in throughput (productivity).

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and has been made in consideration of the above-described problems. It is another object of the present invention to provide an exposure apparatus that can cope with miniaturization of a device and that can improve transfer accuracy.

[0013]

In order to achieve the above object, the present invention employs the following structure corresponding to FIGS. 1 to 5 showing an embodiment. A stage device of the present invention is provided on a stage body (2, 5) that holds and moves a sample (R, W), and on the stage body (2, 5),
Speed detectors (54 to 56, 57 to 59, 61 to 63, 6) for detecting information on the speed of the stage body (2, 5)
4 to 66) and a speed detection unit (54 to 56, 57 to 59,
61 to 63, 64 to 66), and a speed control system for controlling the moving speed of the stage main body (2, 5) based on the detection results.

Therefore, in the stage apparatus of the present invention, the information on the speed of the stage main body (2, 5) is converted into the speed detectors (54 to 56, 57) provided in the stage main body (2, 5).
To 59), the influence of disturbance vibration transmitted to the stage body (2, 5) can be canceled. The speed detectors (54 to 56, 57 to 59, 61 to 63, 64
To 66) do not differentiate the position information, but detect the information on the speed of the stage body (2, 5), so that excellent position controllability can be achieved.

The exposure apparatus of the present invention is directed to 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 apparatus according to claim 1, wherein at least one of the mask stage (2) and the substrate stage (5) is provided.
7) is installed.

Therefore, in the exposure apparatus of the present invention, the mask (R) and the substrate (W) can be positioned with excellent position controllability while eliminating the influence of vibration. The line width error and the position error of the pattern can be suppressed. Therefore, the pattern of the mask (R) can be transferred onto the substrate (W) with a fine line width and high accuracy.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a stage apparatus and an exposure apparatus according to the present invention will be described below with reference to FIGS. Here, an example in which a scanning stepper that transfers a circuit pattern of a semiconductor device formed on a reticle onto a wafer while synchronously moving a reticle and a wafer is used as an exposure apparatus will be described. In this exposure apparatus, the stage apparatus of the present invention is applied to both a reticle stage and a wafer stage. In these figures, the same components as those in FIG. 7 shown as a conventional example are denoted by the same reference numerals, and description thereof will be omitted.

An exposure apparatus 1 shown in FIG. 1 has a light source (not shown).
An illumination optical system IU for illuminating a rectangular (or circular) illumination area on a reticle (mask) R with uniform illumination by exposure illumination light from the reticle, and a reticle stage as a mask stage for holding a reticle R as a sample (Stage body) 2 and a stage device 4 including a reticle surface plate 3 supporting the reticle stage 2, and a projection optical system P for projecting illumination light emitted from a reticle R onto a wafer (substrate) W
L, a stage device 7 including a wafer stage (stage main body) 5 as a substrate stage for holding a wafer W as another sample and a wafer surface plate 6 for holding the wafer stage 5, the stage device 4 and the projection optical system PL And a reaction frame 8 that supports the same. Here, the direction of the optical axis of the projection optical system PL is defined as a Z direction, and the reticle R and the wafer W are aligned in a direction orthogonal to the Z direction.
, And the asynchronous movement direction is the X direction. Also, the rotation directions around the respective axes are θZ, θ
Y and θX.

The illumination optical system IU is supported by a support column 9 fixed on the upper surface of the reaction frame 8. Examples of the illumination light for exposure include far ultraviolet light (DUV light) such as an ultraviolet bright line (g-line, i-line) and KrF excimer laser light (wavelength: 248 nm) emitted from an ultra-high pressure mercury lamp, and ArF. Excimer laser light (wavelength 19
Vacuum ultraviolet light (VUV) such as 3 nm) and F ₂ laser light (wavelength 157 nm).

The reaction frame 8 is installed on a base plate 10 placed horizontally on the floor, and has inwardly projecting step portions 8a and 8b formed on its upper and lower sides, respectively. ing.

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. 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 are arranged in series on the step 8a. With these vibration isolation units 11, micro vibrations transmitted to the reticle surface plate 3 via the base plate 10 and the reaction frame 8 are insulated at a micro G level.

A reticle stage 2 is supported on the reticle base 3 so as to be two-dimensionally movable along the reticle base 3. On the bottom surface of the reticle stage 2, a plurality of air bearings (air pads) which are 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.

The reticle stage 2 will be described in detail.
As shown in FIG. 2, the reticle stage 2 includes a reticle coarse movement stage 16 that is driven on the reticle surface plate 3 by a pair of Y linear motors 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 is provided above and supported by a plurality of air bearings (air pads) 19 and extends in the Y-axis direction. The stator 20 is provided corresponding to the stator 20 and fixed to the reticle coarse movement stage 16 via a connecting member 22. And a mover 21. In addition, as an example, the stator 20 is configured by a magnet unit, and the mover 21 is configured by an armature coil.

The reticle coarse movement stage 16 is fixed to the upper surface of an upper protruding portion 3b formed at the center of the reticle surface plate 3 and guided in the Y-axis direction by a pair of Y guides 51, 51 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 (all not shown) for irradiating the movable mirrors 52a, 52b, and 53 with a length measurement beam.
By measuring the distance from each movable mirror, the position of the reticle stage 2 in the X, Y, θZ (rotation around the Z axis) direction can be measured with high accuracy.

As shown in FIG. 3, the reticle fine movement stage 18 has speed sensors (speed detection units) 54, 5 for detecting the moving speed of the reticle fine movement stage 18.
5 and 56 are provided in pairs (in FIG. 3, components arranged in the center of the stage 18 are omitted). The speed sensors 54 detect the moving speed of the reticle fine movement stage 18 in the Y direction, and are provided on both side edges of the reticle fine movement stage 18 in the X direction. The speed sensors 54 are arranged at positions sandwiching the center of gravity of the reticle stage 2 including the reticle R, the reticle coarse movement stage 16, the reticle fine movement stage 18, and the like.

The speed sensors 55 and 56 both detect the moving speed of the reticle fine movement stage 18 in the X direction, and are provided on both side edges of the reticle fine movement stage 18 in the Y direction. These speed sensors 5
Similarly to the speed sensor 54, the reference numerals 5 and 56 are arranged with the center of gravity of the reticle stage 2 interposed therebetween. Each of the speed sensors 54, 55, 56 has a structure having a coil and a magnet therein, and the Lorentz force (F = q (v × B); B is generated by the relative movement between the coil and the magnet; The configuration is such that the speed of the reticle fine movement stage 18 is detected from the relationship between the magnetic flux density and v (the speed of the charged particles of the electric quantity q) and output to a control system (speed control system) not shown.

The control system carries out arithmetic processing on the detection results of the speed sensors 54 to 56 by a CPU as an arithmetic unit, and performs coarse movement of the reticle through the Y linear motors 15, 15, the X voice coil motor 17X, and the Y voice coil motor 17Y. Stage 16
The driving speed of the reticle fine movement stage 18 is controlled. As the drive control, as shown in FIG. 4, a speed control loop SR that forms a speed servo based on the detection results of the speed sensors 54 to 56 is a minor loop, and the speed control loop SR is based on the detection result of the laser interferometer. A so-called cascade control system is formed in which the position control loop PR to be controlled is a main loop.

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 visual 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, of the circuit pattern on the reticle R, an image forming light beam from a portion illuminated by the illumination light enters the projection optical system PL, and the circuit pattern is partially inverted. The image is limited to a slit shape and formed at the center of the circular field on the image plane side of the projection optical system PL. Thus, the projected partial inverted image of the circuit pattern is transferred to the wafer W placed on the image forming plane of the projection optical system PL.
Of the plurality of upper shot areas, the reduced transfer is performed to the resist layer on the surface of one shot area.

On the outer periphery of the lens barrel of the projection optical system PL, a flange 23 integrated with the lens barrel is provided. Then, 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 step portion 8b of the reaction frame 8 via a vibration isolating unit 24 with the optical axis direction being the Z direction. And the flange 23 is engaged.

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 on the back side of the drawing is not shown), and an air mount 26 whose internal pressure can be adjusted.
And the voice coil motor 27 are 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.

The stage device 7 mainly includes a wafer stage 5 for holding a wafer W, and a wafer surface plate 6 for supporting the wafer stage 5 movably in a two-dimensional direction along the XY plane. A plurality of air bearings (air pads) 28 which are non-contact bearings are fixed to the bottom surface of the wafer stage 5.
The wafer stage 5 is floated and supported on the wafer surface plate 6 by a clearance of, for example, about several microns.

The wafer surface plate 6 is supported substantially horizontally above the base plate 10 via an anti-vibration unit 29. The anti-vibration unit 29 is disposed at each corner of the wafer surface plate 6 (the anti-vibration unit on the back side of the drawing is not shown), and the air mount 30 and the voice coil motor 31 whose internal pressure can be adjusted include the base plate 10. It has a configuration arranged in parallel on the top. These anti-vibration units 29
Thus, micro vibration transmitted to the wafer surface plate 6 via the base plate 10 is insulated at the micro G level.

The wafer stage 5 is
A pair of linear motors 32 for driving the wafer in the X direction (a linear motor on the front side of the paper surface with respect to the wafer stage 5 is not shown)
And a pair of linear motors 33 for driving the wafer stage 5 in the Y direction, so that the wafer stage 5 can be moved on the wafer surface plate 6 in the XY two-dimensional directions. The stator of the linear motor 32 is extended along the X direction on both outer sides of the wafer stage 5 in the Y direction, and both ends are connected to each other by a pair of connecting members 34 to form a rectangular frame 35. Have been.
The mover of the linear motor 32 is provided on both sides of the wafer stage 5 in the Y direction so as to face the stator.

On the lower end surfaces of the pair of connecting members 34 or the linear motor 32 constituting the frame 35, movers 36, 36 each composed of an armature unit are provided, respectively. Are extended in the Y direction and protrude from the base plate 10. The moving coil 36 and the stator 37 constitute a moving coil type linear motor 33. The moving element 36 is driven in the Y direction by electromagnetic interaction with the stator 37. I have. That is, this linear motor 33
Thereby, the wafer stage 5 is driven integrally with the frame 35 in the Y direction.

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. 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. The measurement is performed in real time by the laser interferometer 44 at a predetermined resolution, for example, about 0.5 to 1 nm. The reference mirror 42, the moving mirror 43,
The position of the wafer stage 5 in the Y direction is measured by a reference mirror, a moving mirror, and a laser interferometer (not shown) that are arranged substantially orthogonal to the laser interferometer 44. 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, the XY
In addition to the position, the θ rotation amount or the leveling amount in addition to the θ rotation amount can be obtained.

Further, similarly to the reticle stage 2, the wafer stage 5 is provided with a pair of speed sensors (speed detecting units) 57, 58, 59 for detecting the moving speed of the wafer stage 5. The speed sensor 57 detects the moving speed of the wafer stage 5 in the Y direction.
It is provided on both side edges of the wafer stage 5 in the X direction. These speed sensors 57 are arranged at positions sandwiching the center of gravity of the wafer stage 5 including the wafer W, the wafer holder 41 and the like.

The speed sensors 58 and 59 both detect the moving speed of the wafer stage 5 in the X direction, and are provided on both side edges of the wafer stage 5 in the Y direction. These speed sensors 58 and 59 are also arranged so as to sandwich the center of gravity of wafer stage 5 similarly to speed sensor 57. Each speed sensor 57-59
Has a structure having a coil and a magnet inside thereof, like the speed sensors 54 to 56, and detects the speed of the wafer stage 5 from the relationship of Lorentz force generated with the relative movement between the coil and the magnet. , Output to a control system (not shown).

The control system calculates the detection results of the speed sensors 57 to 59 by a CPU as a calculation unit,
The drive speed of the movement of the wafer stage 5 is controlled via 2 and 33. As in the reticle stage 2, as shown in FIG. 4, the speed control loop SR that forms the speed servo based on the detection results of the speed sensors 57 to 59 is a minor loop, and the drive control is performed based on the detection result of the laser interferometer. A so-called cascade control system is formed in which a position control loop PR that controls the speed control loop SR based on the main loop is used.

The reticle surface plate 3, the wafer surface plate 6, and the lens barrel surface plate 25 each include three vibration sensors (for example, an accelerometer; not shown) for measuring the vibration of each surface plate in the Z direction.
Three vibration sensors (for example, an accelerometer; not shown) for measuring the vibration in the Y-plane direction are respectively attached.
Two of the latter 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, for convenience, these vibration sensors are referred to as a vibration sensor group). Name). Then, vibrations of the reticle surface plate 3, the wafer surface plate 6, and the lens barrel surface plate 25 with six degrees of freedom (X, Y, Z, θX, θY, θZ) are obtained based on the measurement values of these vibration sensor groups. be able to.

Further, three laser interferometers 45 are fixed to three different places on the flange 23 of the projection optical system PL (however, one of these laser interferometers is representatively shown in FIG. 1). Has been). Openings 25a are formed in portions of the barrel base 25 facing each of the laser interferometers 45, and a measurement beam in the Z direction is sent from each laser interferometer 45 through these openings 25a to the wafer base. Irradiation toward 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 state where the central shot area of the wafer W on the wafer stage 5 is directly below the optical axis of the projection optical system PL is shown, so that the length 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.

Next, the operation of the stage device 4 among the stage devices 4 and 7 having the above configuration will be described first. The control system processes the outputs of the speed sensors 54 to 56 and the output of the laser interferometer based on the control loop shown in FIG. 4 to control the position of the reticle stage 2. Specifically, first, the control system averages the output for each of the speed sensors 54 to 56.
Thereby, the speed at the position of the center of gravity of the reticle stage 2 can be obtained by the approximate calculation in both the X direction and the Y direction.

Next, for a given target value (target position), a function unit C1 such as a PID controller or the like, in a position control loop PR, based on the positional deviation between the target value and the measurement result of the laser interferometer. The speed at which the reticle stage 2 is moved is output. In the speed control loop SR, P
The function part C2 of the ID controller or the like includes speed sensors 54 to
The driving force of the reticle stage 2 is output based on the speed deviation between the speed at the position of the center of gravity of the reticle stage 2 detected by 56 and the speed output from the function section C1. Then, the linear motor 15, the voice coil motor 17X,
7Y is driven by the output driving force, and the speed of the reticle stage 2 is controlled to a predetermined speed by feeding back the measurement results of the speed sensors 54 to 56. Thereafter, the position information measured by the laser interferometer and the speed sensors 54 to 5 until the reticle stage 2 reaches the predetermined position.
The position / position control loop PR controls the speed control loop SR based on the position of the reticle stage 2 obtained by integrating (calculating) the speed detected by the speed controller 6.

In the case of the wafer stage 5 as well, similarly to the reticle stage 2, the control system first averages the output of each of the speed sensors 57 to 59, so that the center of gravity of the wafer stage 5 in both the X direction and the Y direction. Is calculated by an approximate calculation. Next, for the given target value, the function part C1 outputs the speed at which the wafer stage 5 is moved in the position control loop PR based on the positional deviation between the target value and the measurement results of the laser interferometers 44 and 45. I do.
Then, the linear motors 32 and 33 are driven by the output driving force, and the measurement results of the speed sensors 57 to 59 are fed back to control the speed of the wafer stage 5 to a predetermined speed. Thereafter, until the wafer stage 5 reaches a predetermined position, the position information measured by the laser interferometers 44 and 45 and the position of the wafer stage 5 obtained by integrating the speeds detected by the speed sensors 57 to 59 are used. The position / position control loop PR controls the speed control loop SR.

In the reticle stage 2 and the wafer stage 5, the speed sensors 54 to 56 and 57 to 59 detect the speeds of the stages 2 and 5 in the X and Y directions, and also determine the speed components in the θZ direction. Can be detected at the same time.

In the reticle stage 2,
Reticle coarse movement stage 16 is reticle fine movement stage 18
When the Y linear motor 1 fixed to the reticle coarse movement stage 16 moves in the scanning direction (Y-axis direction)
The movers 21 and the stator 20 of 5 and 15 relatively move in opposite directions. That is, the reticle stage 2 and the stator 2
0 relatively moves in the opposite direction. Reticle stage 2
When the friction between the three members of the reticle stage 2 and the reticle surface plate 3 is zero, the law of conservation of momentum is satisfied, and the movement amount of the reticle stage 2 is controlled by the entire reticle stage 2 (reticle coarse movement stage 16). , Reticle fine movement stage 18, connecting member 22, mover 21, reticle R, etc.) and the entire stator (stator 20, air bearing 19, etc.). Therefore, the reaction force of the reticle stage 2 during acceleration / deceleration in the scanning direction is absorbed by the movement of the stator 20, and
The reticle surface plate 3 can be prevented from vibrating due to the reaction force. In addition, the reticle stage 2 and the stator 20 move relatively in opposite directions, and the center of gravity of the entire system including the reticle stage 2, the reticle base 3, and the like is maintained at a predetermined position. Eccentric load is not generated.

Next, the exposure operation of the exposure apparatus 1 having the above configuration will be described below. 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.
Preparation work such as reticle alignment and baseline measurement using a reticle microscope and an off-axis alignment sensor (not shown) is performed, and then fine alignment of wafer W using an alignment sensor (EGA; enhanced global) is performed. (Alignment etc.) is completed, and the arrangement coordinates of a plurality of shot areas on the wafer W are obtained.

When the preparatory operation for the exposure of the wafer W is completed in this way, the linear motors 32 and 33 are controlled while monitoring the measurement values of the laser interferometer 44 based on the alignment result to control 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,
The pattern area of the reticle R is illuminated by the exposure illumination light, and scanning exposure is started.

At the time of this scanning exposure, the reticle stage 2
And the moving speed of the wafer stage 5 in the Y direction is maintained at a speed ratio corresponding to 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 motors 15 and 33. And reticle R
Different areas of the pattern area are sequentially illuminated with illumination light,
By completing the illumination of the entire pattern area,
The scanning exposure of the first shot on the wafer W is completed. Thereby, the pattern of reticle R is reduced and transferred to the first shot area on wafer W via projection optical system PL.

When the scanning exposure of the first shot is completed in this way, the wafer stage 5 is moved stepwise in the X and Y directions via the linear motors 32 and 33, and moves to the scanning start position for the exposure of the second shot. Be moved. At the time of this step movement, the position of the wafer stage 5 in the X, Y, and θZ directions is measured in real time based on the measurement value of the laser interferometer 44 that detects the position of the wafer stage 5 (the position of the wafer W). And, based on this measurement result,
By controlling the linear motors 32 and 33, the position of the wafer stage 5 is controlled so that the XY position displacement of the wafer stage 5 becomes a predetermined state. Further, with respect to the displacement of wafer stage 5 in the θZ direction, rotation of reticle stage 2 (reticle fine movement stage 18) is controlled so as to correct a rotational displacement error on wafer W side based on the information on the displacement.
Thereafter, similarly to the first shot area, the second shot area is subjected to scanning exposure.

In this manner, the scanning exposure of the shot area on the wafer W and the step movement for the next shot exposure are repeatedly performed, and the pattern of the reticle R is sequentially transferred to all the exposure target shot areas on the wafer W. Is done.

In the stage apparatus and the exposure apparatus of the present embodiment, the moving speeds of the reticle stage 2 and the wafer stage 5 are not differentiated from the position information, but are velocity sensors 54 to 56 and 57 to 59 having coils and magnets. , The positions of the stages 2 and 5 can be controlled with high accuracy without being restricted by the position detection resolution, sampling time, and the like. In addition, since these speed sensors 54 to 56 and 57 to 59 are respectively mounted on the stages 2 and 5, the speed sensors 54 to 56 and 57 to 59 are generated on the reaction frame 8 and the base plate 10 by a reaction force or the like accompanying the movement of each of the stages 2 and 5. The influence of disturbance such as micro vibration can be eliminated, and the positions of the stages 2 and 5 can be controlled with high accuracy. Moreover, since the reticle base 3 is supported by the reaction frame 8 via the vibration isolating unit 11 and the wafer base 6 is supported by the base plate 10 via the vibration isolating unit 29, the residual vibration of the reaction frame 8 and the base plate 10 Is prevented from being transmitted to the reticle platen 3 and the wafer platen 6, whereby the position controllability of each of the stages 2, 5 can be maintained. Therefore, if the exposure processing is performed using the reticle R and the wafer W held on these stages 2 and 5, it is possible to prevent the pattern line width from increasing due to vibration and the occurrence of positional errors in the transferred pattern. it can.

In addition, in the present embodiment, since reticle stage 2, wafer stage 5, and projection optical system PL are vibrationally independent by vibration isolating units 11, 29, and 24, reticle stage 2 and upper wafer stage 5
Can be prevented from being transmitted to the projection optical system PL due to the driving of the projection optical system PL, and the shift of the pattern transfer position and the occurrence of image blur due to the vibration of the projection optical system PL can be effectively prevented, thereby improving the exposure accuracy. You can also plan.

In this embodiment, each speed sensor 5
4 to 56 and 57 to 59 are arranged on both sides of the center of gravity in each of the stages 2 and 5, so that each speed sensor 5
By averaging the measurement results of 4 to 56 and 57 to 59, the speed at the center of gravity of each stage 2 and 5 can be approximately obtained, and the speed control of each stage 2 and 5 can be performed with higher accuracy. Thus, excellent position controllability can be achieved.

In this embodiment, since the speed sensors are provided for each of the stages 2 and 5 in each of the X and Y directions, excellent position control in both directions can be achieved. The stages 2, 5 can be accurately moved to the target position not only in the scanning movement direction but also in the non-scanning step movement direction.

FIG. 5 is a view showing a stage apparatus and an exposure apparatus according to a second embodiment of the present invention. In this figure, the same components as those of the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the second embodiment and the first embodiment is that the reticle stage 2 and the wafer stage 5 are provided with acceleration sensors instead of the speed sensors.

That is, in the present embodiment, as shown in FIGS. 1 to 3, a speed detecting section is provided at the position where the speed sensors 54 to 56 and 57 to 59 described in the first embodiment are provided. Reticle stage 2 has acceleration sensors 61 to 6
3 is provided with acceleration sensors 64 to 66 on the wafer stage 5, respectively.

The acceleration sensor 61 detects the acceleration of the reticle fine movement stage 18 in the Y direction. A reticle R, a reticle coarse movement stage 16 and a reticle fine movement stage 18 are provided on both sides of the reticle fine movement stage 18 in the X direction. The reticle stage 2 is disposed at a position sandwiching the center of gravity of the reticle stage 2. The acceleration sensors 62 and 63 both detect the acceleration of the reticle fine movement stage 18 in the X direction, and are provided at both sides of the reticle fine movement stage 18 in the Y direction at positions sandwiching the center of gravity of the reticle stage 2. ing.

Similarly, the acceleration sensor 64 detects the acceleration of the wafer stage 5 in the Y direction, and the center of gravity of the wafer stage 5 including the wafer W, the wafer holder 41 and the like is provided on both side edges of the wafer stage 5 in the X direction. It is provided at a position sandwiching. The acceleration sensors 65 and 66 both detect the moving speed of the wafer stage 5 in the X direction, and are provided at both sides of the wafer stage 5 in the Y direction at positions sandwiching the center of gravity of the wafer stage 5. .

Each of the acceleration sensors 61-63, 64-66
Has, for example, a pendulum therein and electromagnets arranged on both sides of the pendulum in the direction of acceleration detection, and adjusts the intensity of the current applied to the electromagnet so that the pendulum is always at the center position. In that case, the acceleration is detected from the magnitude of the required current. The detected acceleration is output to a control system (speed control system).

The control system includes acceleration sensors 61 to 63, 64
The detection results of Nos. 66 are calculated by a CPU as a calculation unit,
Y linear motors 15, 15, X voice coil motor 17
The moving speed of the reticle coarse moving stage 16 and the moving speed of the reticle fine moving stage 18 are controlled by the X and Y voice coil motors 17Y, and the moving speed of the wafer stage 5 is controlled by the linear motors 32 and 33, respectively. As the drive control, as shown in FIG.
A cascade control in which a speed control loop SR for forming a speed servo based on the detection results of 64 to 66 is a minor loop, and a position control loop PR for controlling the speed control loop SR based on a detection result of the laser interferometer is a main loop. A system has formed. Other configurations are the same as those of the first embodiment.

The operation of the stage devices 4 and 7 having the above configuration will be described. Here, the reticle stage 2 and the wafer stage 5 will be described simultaneously, but the actual control is performed independently. First, the control system averages the output for each of the acceleration sensors 61 to 63 and 64 to 66. Thus, the acceleration at the position of the center of gravity of reticle stage 2 and wafer stage 5 in both the X direction and the Y direction can be obtained by approximate calculation.

Next, for a given target value (target position), a function unit C1 such as a PID controller or the like, in a position control loop PR, based on the positional deviation between the target value and the measurement result of the laser interferometer. The speed at which the reticle stage 2 and the wafer stage 5 are moved is output. Then, in the speed control loop SR, the acceleration sensors 61 to 63,
The moving speed of each of the stages 2 and 5 is calculated by integrating (calculating) the accelerations detected by the 64-64. P
The function part C2 of the ID controller or the like includes the calculated speeds of the reticle stage 2 and the wafer stage 5 and the function part C1.
The driving force of reticle stage 2 and wafer stage 5 is output based on the speed deviation from the speed output from. Then, the linear motors 15, 32, 33 and the voice coil motors 17X, 17Y are driven by the output driving force, and the measurement results of the acceleration sensors 61 to 63, 64 to 66 are fed back, so that the reticle stage 2, the wafer The moving speed of the stage 5 is controlled to a predetermined speed.

Thereafter, until the reticle stage 2 and the wafer stage 5 reach predetermined positions, the laser interferometer 4
The position information measured by the sensors 4 and 45 and the acceleration sensors 61 to 6
3, the position and position control loop PR is based on the position of the reticle stage 2 and the position of the wafer stage 5 obtained by integrating the speeds detected by the 64 to 66 twice.
Control. In the reticle stage 2 and the wafer stage 5, the acceleration sensors 61 to 63 and 64 to 66 detect the accelerations of the stages 2 and 5 in the X and Y directions, respectively, and can simultaneously detect the acceleration components in the θZ direction. .

In the stage apparatus and the exposure apparatus of the present embodiment, in addition to the same effects as those of the first embodiment, the moving speed of the reticle stage 2 and the wafer stage 5 can be obtained by integrating the acceleration. I am looking for
Smooth and more accurate moving speed can be detected as if filtered. For this reason, it is possible to control the positions of the stages 2 and 5 with higher accuracy, and it is possible to expect further miniaturization of the device and improvement of transfer accuracy.

In the above embodiment, the speed sensor or the acceleration sensor is provided on both the reticle stage 2 and the wafer stage 5, but may be provided on only one of the stages. Further, one may be provided with a speed sensor and the other with an acceleration sensor. Further, in the above embodiment, the speed sensor or the acceleration sensor is provided in correspondence with the X direction and the Y direction, but in the case of the scanning type exposure apparatus, the speed sensor or the acceleration sensor is provided only in the scanning movement direction. It may be a configuration. In the above embodiment, the stage apparatus of the present invention is applied to the exposure apparatus 1.
The present invention is not limited to this, and can be applied to precision measuring devices such as a transfer mask drawing device and a mask pattern position coordinate measuring device other than the exposure device 1. Further, in the above embodiment, the linear motors 15, 32, 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 can also be applied 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 an equal magnification system or 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 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.

As shown in FIG. 6, for a semiconductor device, a step 201 for designing the function and performance of the device, a step 202 for manufacturing a mask (reticle) based on the design step, a step 203 for manufacturing a wafer from a silicon material A wafer processing step 204 of exposing a reticle pattern to a wafer by the exposure apparatus 1 of the above-described embodiment, a device assembling step (dicing step,
(Including a bonding step and a package step) 205, an inspection step 206, and the like.

[0078]

As described above, in the stage device according to the first aspect, the speed detecting section provided on the stage main body detects information on the speed of the stage main body, and the speed control system is based on the detection result. The moving speed of the stage body is controlled. Thus, in this stage device, the speed detecting unit directly detects the moving speed of the stage main body in a state where the influence of the disturbance is eliminated, so that the position of the stage main body is not restricted by the position detection resolution and the sampling time. The effect that control can be performed with high precision is obtained.

The stage device according to the second aspect is configured such that the speed detecting section has a coil and a magnet. Thereby, in this stage device, the moving speed of the stage main body is detected based on the magnetic flux density according to the relative speed between the coil and the magnet, so that the stage device is not affected by restrictions such as position detection resolution and sampling time and disturbance. Thus, the effect that the position of the stage body can be controlled with high accuracy can be obtained.

According to a third aspect of the present invention, the speed detecting section detects the acceleration accompanying the movement of the stage main body, and the calculating section of the speed control system calculates the detected acceleration to obtain the moving speed of the stage main body. It has a configuration. Thus, in this stage device, the movement speed can be detected more smoothly and more accurately, so that the effect of controlling the position of the stage body with higher accuracy can be obtained.

The stage device according to the fourth aspect has a configuration in which the speed detecting section is provided corresponding to each of the plurality of moving directions of the stage body. As a result, in this stage device, excellent position controllability can be exhibited in all the moving directions of the stage main body. For example, the position control of the stage main body can be enhanced not only in the scanning moving direction but also in the non-scanning step moving direction. The effect that it can be implemented with high accuracy is obtained.

In the stage device according to the fifth aspect, the speed detecting section is arranged on both sides of the center of gravity of the stage body. Thus, in this stage device, by averaging the measurement results of the speed detection unit, the speed at the center of gravity of the stage body can be obtained, and by performing the speed control of the stage body with higher accuracy, excellent position control is achieved. The effect of exhibiting the effect is obtained.

The exposure apparatus according to claim 6 is configured such that the stage device according to any one of claims 1 to 5 is installed as at least one of a mask stage and a substrate stage. As a result, in this exposure apparatus, the position of the mask and the substrate can be controlled with high precision while eliminating the influence of disturbances such as reaction force due to the movement of the stage body, and the pattern of the mask can be linearly adjusted. The transfer to the substrate can be performed without increasing the width or generating a position error, and the effect of improving the exposure accuracy can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention, and is a schematic configuration diagram of an exposure apparatus in which a reticle stage, a wafer stage, and a projection optical system are independently arranged with respect to vibration.

FIG. 2 is an external perspective view of a reticle stage included in the exposure apparatus.

FIG. 3 is a schematic plan view in which a speed sensor is arranged on a side edge of the reticle stage.

FIG. 4 is a diagram showing the first embodiment of the present invention, and is a control loop diagram of a cascade control system in which a speed control loop is a minor loop and a position control loop is a main loop.

FIG. 5 is a view showing a second embodiment of the present invention, and is a control loop diagram of a cascade control system in which a speed control loop is a minor loop and a position control loop is a main loop.

FIG. 6 is a flowchart illustrating an example of a manufacturing process of a semiconductor device.

FIG. 7 is a control loop diagram showing an example of a conventional control system.

[Explanation of symbols]

R Reticle (mask, sample) W Wafer (substrate, sample) 1 Exposure device 2 Reticle stage (mask stage, stage body) 4, 7 Stage device 5 Wafer stage (substrate stage, stage body) 54, 55, 56, 57, 58, 59 Speed sensor (speed detection unit) 61, 62, 63, 64, 65, 66 Acceleration sensor (speed detection unit)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/30 516B 525D

Claims (6)

[Claims] A stage body that holds and moves a sample; a speed detection unit that is provided on the stage body and detects information about the speed of the stage body; and the stage based on a detection result of the speed detection unit. A stage device comprising a speed control system for controlling a moving speed of a main body. 2. The stage device according to claim 1, wherein the speed detector has a coil and a magnet. 3. The stage device according to claim 1, wherein the speed detection unit detects an acceleration associated with movement of the stage body, and the speed control system performs an arithmetic processing on the detected acceleration to perform the stage operation. A stage device comprising a calculation unit for calculating a moving speed of a main body. 4. The stage device according to claim 1, wherein the stage main body moves in a plurality of directions, and the speed detecting section is provided corresponding to each of the plurality of directions. A stage device characterized by the above-mentioned. 5. The stage device according to claim 1, wherein the speed detector is disposed on both sides of a center of gravity of the stage body. 6. 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. An exposure apparatus, wherein the stage device according to any one of the above is installed.