JPH11325832A - Method and apparatus for measuring position, and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aligner, a method and an apparatus which makes it possible to take high-precision measurement of the position of an XY stage even take by a plane mirror having a length shorter than a moving stroke, and to realize cost reduction and a high control performance of the stage. SOLUTION: Since second light-wave interferometers (LY1 , LY2 ) for measuring the coordinate position Y of a stage relating to the second position (y-direction) are switched over, and a measuring position in the first direction is switched over, in accordance with the coordinate position X of the stage 8 relating to a first direction (x-direction) measured on the basis of the output of a first light wave interferometer LX, high-precision position measurement in the second direction becomes feasible, even if a reflecting surface RY shorter than the first-direction moving stroke of the stage is used. Furthermore, it is possible to reduce the cost of the apparatus and to make the performance of movement control of time stage higher, by shortening the reflecting surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring method and a position measuring apparatus for a stage which moves two-dimensionally in a plane, and an exposure apparatus. In particular, extremely high precision is required for processing and inspection of a semiconductor device. TECHNICAL FIELD The present invention relates to a position measuring method, a position measuring device, and an exposure device which are suitable for use in performing measurement.

[0002]

2. Description of the Related Art In general, various exposure apparatuses (steppers, etc.), transfer mask drawing apparatuses, mask pattern position coordinate measuring apparatuses, and other positioning apparatuses used for VLSI pattern transfer hold an object and hold the object at right angles. An XY stage that moves precisely in two axes (X and Y axes) is used. For the coordinate measurement of the XY stage, for example, a light wave interferometer (laser interferometer) using a He-Ne frequency stabilized laser continuously oscillating at a wavelength of 633 nm as a light source is used.

[0003] Since a laser interferometer can essentially only perform one-dimensional measurement, two identical laser interferometers are prepared for two-dimensional coordinate measurement. For example, as shown in FIG. 5, two plane mirrors M1 and M2 whose reflection surfaces are substantially orthogonal to each other are fixed to the XY stage S, and beams B1 and B2 from the laser interferometers K1 and K2 are respectively mounted on the two plane mirrors. Project B2,
The two-dimensional coordinate position of the XY stage S can be obtained by measuring the vertical distance change of each reflection surface. Each reflecting surface of the two plane mirrors extends in the x direction and the y direction in accordance with the required movement stroke of the stage.

[0004]

However, the conventional position measuring means as described above has the following problems. That is, conventionally, in order to obtain the x-direction movement stroke L of the XY stage S, the length of the plane mirror M1 extending in the x direction is required to be at least L, and the XY stage S to which it is attached is also required to have high accuracy. Therefore, the stage becomes large, and as a result, the natural frequency of the stage decreases,
When controlling the movement of the XY stage, there is a problem that a required control response cannot be obtained. Also, depending on the length of the plane mirror, it is difficult to manufacture a long mirror having the required surface accuracy, and even if it can be manufactured, it is very expensive and disadvantageous in terms of cost. there were.

The present invention has been made in view of the above points, and it is possible to measure the position of the XY stage with high accuracy even with a plane mirror having a length shorter than the moving stroke, thereby reducing the cost and the stage size. An object of the present invention is to provide a position measuring method, a position measuring device, and an exposure device that can realize high control performance.

[0006]

In order to achieve the above object, the present invention employs the following structure corresponding to FIGS. 1 to 4 showing an embodiment. The position measuring method according to claim 1, wherein the stage (8) is provided on the stage (8) so as to reflect light incident from the first direction (x direction) in the reverse direction.
Light incident on the reflector (MX) from a second direction (y direction) orthogonal to the first direction is reflected by a reflecting surface (RY) along the first direction.
And the second reflector (MY) provided on the stage so as to reflect in the opposite direction with the laser beams (BX, BY), respectively.
1, BY2) and a second light interferometer (LX)
A method of measuring a coordinate position (X, Y) of a stage based on an output from a light wave interferometer (LY1, LY2), wherein a plurality of second light wave interferometers are used to measure a reflection surface of the second reflector. A plurality of laser beams are respectively applied to positions separated from each other in the first direction, and according to a coordinate position (X) of the stage in the first direction measured based on an output of the first light wave interferometer. The technique of switching the second light wave interferometer for measuring the coordinate position of the stage in the second direction and switching the measurement position in the first direction is adopted.

According to a fifth aspect of the present invention, there is provided a position measuring device, wherein a laser is applied to a first reflector (MX) provided on a stage (8) so as to reflect light incident from a first direction (x direction) in a reverse direction. A first light wave interferometer (L) for irradiating a beam (BX)
X) and a second reflector provided on the stage such that light incident from a second direction (y direction) orthogonal to the first direction is reflected in a reverse direction by a reflecting surface (RY) along the first direction. A second light wave interferometer (LY1, LY2) for irradiating (MY) with a laser beam (BY1, BY2); and the stage in the first and second directions based on outputs of the first and second light wave interferometers. And a calculator (12) for calculating the coordinate position (X, Y) of the second light wave interferometer, wherein the second light wave interferometer is located at a position separated from the reflection surface of the second reflector in the first direction. A plurality of the plurality of laser beams are provided so as to irradiate the plurality of laser beams, respectively, and the arithmetic unit is configured to perform the second operation in accordance with a coordinate position of the stage in the first direction calculated based on an output of the first optical interferometer. Of the coordinate position of the stage with respect to the direction Switching said second light wave interferometer is used to output, have been set techniques are employed to switch the measurement position in the first direction.

In this position measuring method and position measuring apparatus, the position (X) of the stage (8) in the first direction (x direction) measured based on the output of the first light wave interferometer (LX) is A second light wave interferometer (LY1, LY1) for measuring the coordinate position (Y) of the stage in the second direction (y direction)
LY2), and the measurement position in the first direction is switched. Therefore, even if a reflecting surface (RY) shorter than the movement stroke of the stage in the first direction is used, highly accurate position measurement in the second direction can be performed. Further, by reducing the length of the reflecting surface, it is possible to reduce the cost of the apparatus and to improve the performance of stage movement control.

In an exposure apparatus according to the present invention, at least one of a mask stage (7) for holding a mask (R) and a substrate stage (8) for holding a substrate (W) onto which a pattern of the mask is transferred. An alignment for providing a position measuring device (10) according to claim 5, and adjusting an exposure position of the substrate with respect to the pattern of the mask using a coordinate position (X, Y) of the stage obtained by the position measuring device. -The technology provided with the controller (12) is adopted.

In this exposure apparatus (1), the alignment
The controller (12) adjusts the exposure position of the substrate (W) with respect to the pattern of the mask (R) using the coordinate position (X, Y) of the stage (8) obtained by the position measuring device (10). Therefore, the exposure process is accurately performed by the highly accurate positioning.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a position measuring method, a position measuring apparatus and an exposure apparatus according to the present invention will be described below with reference to FIGS. Here, in a scanning type exposure apparatus that exposes a reticle pattern by synchronously moving a reticle and a wafer with a position measuring device, a wafer stage that holds a wafer that is an object to be subjected to a predetermined process (exposure process) This will be described with reference to an example of a case in which the information is provided. Note that directions substantially orthogonal to the movement of the wafer stage are defined as an x direction (first direction) and a y direction (second direction).

In FIG. 2, reference numeral 1 denotes an exposure apparatus. The exposure apparatus 1 includes an exposure apparatus main body 4 mounted on a surface plate 3 whose vibration is prevented by the vibration isolation tables 2 and 2, and a chamber 5 surrounding the exposure apparatus main body 4. The exposure apparatus main body 4 is provided with an illumination optical system 6 and a projection optical system PL.

The illumination optical system 6 includes an optical integrator (fly-eye lens or rod integrator), a variable field stop (reticle blind), and the shape and size of exposure light (for example, a secondary light source) on its pupil plane. Includes an aperture stop that regulates the exposure light
It illuminates an illumination area on a reticle (mask) R defined by blinds. The projection optical system PL
The pattern image of the reticle R illuminated by the illumination optical system 6 is １ ／ or 1
/ 5 and sequentially projected.

The reticle R is held on a reticle stage (mask stage) 7 that moves two-dimensionally by a motor (not shown) in a plane perpendicular to the optical axis of the projection optical system PL. The wafer W is held on a wafer stage (substrate stage) 8. As shown in FIG. 1, the wafer stage 8 is provided with a motor 9X for moving the wafer stage 8 in the x direction and a motor 9Y for moving the wafer stage 8 in the y direction.

A movable mirror (first reflector) MX and a movable mirror (second reflector) MY, which are plane mirrors, are fixed on the wafer stage 8 at edges perpendicular to each other of the wafer stage 8. The movable mirror MX is provided such that the reflection surface RX extends along the y direction. Moving mirror MY
Are provided such that the reflection surface RY extends along the x direction.

The length of the wafer stage 8 in the x direction is half that of the conventional one, that is, the length of the conventional wafer stage is L, whereas the length of the wafer stage 8 of the present embodiment is L / L. It is set to 2. Along with this,
The reflecting surface RY of the movable mirror MY is also set to a length L / 2. The wafer stage 8 has a position measuring device 10
Is provided.

The position measuring device 10 measures the coordinate position of the wafer stage 8 in the x direction and the y direction, and has a configuration including a laser interferometer (light wave interferometer) 11 and an alignment controller 12. I have.
The laser interferometer 11 includes an interferometer LX (first optical interferometer) and a pair of interferometers (second optical interferometer) LY1 and LY2.

Interferometer LX and interferometers LY1 and LY2
Is a plane mirror interferometer using He-Ne laser beams BX, BY1, and BY2,
Are detected in the x direction and the Y direction. As shown in FIG. 1, a beam BX from an interferometer LX is vertically projected on a reflection surface RX of a moving mirror MX. Also,
The measuring beams BY1 and BY2 from the interferometers LY1 and LY2 are vertically projected on the reflecting surface RY of the movable mirror MY.

The interval between the measuring beams BY1 and BY2 is set to be at least smaller than the length L / 2 of the reflecting surface RY, and is set to be longer than the stroke which moves when scanning and exposing one area. That is, the interferometer LY1
And the interferometer LY2 measure the coordinate position of the wafer stage 8 in the y direction at separate measurement positions separated from each other in the x direction.

On the other hand, an alignment controller (arithmetic unit) 12 adjusts the exposure position of the wafer W with respect to the pattern of the reticle R, and is based on outputs from the interferometer LX and the interferometers LY1 and LY2. , The coordinate position of the wafer stage 8 and the like, and a feedforward or feedback operation is performed based on the command of the coordinate position and the target position.
To drive the motors 9X and 9Y. Therefore, the motors 9X and 9Y function as drive devices for synchronously driving the wafer stage 8 and the reticle stage 7 along the x direction during scanning exposure based on a command from the controller.

The alignment controller 12 is shown in FIG.
As shown in the figure, based on the position commands in the x and Y directions (X position command, Y position command) and the coordinate positions in the x and Y directions (coordinate position X, coordinate position Y), the PI
Performs well-known servo calculations such as D control and performs motor 9
An X servo operation unit 12X and a Y servo operation unit 12Y that send drive signals (X drive signal and Y drive signal) to X and 9Y,
A Y1 / Y2 switching operation unit 12YY for performing a switching operation between a coordinate position Y1 obtained by the interferometer LY1 and a coordinate position Y2 obtained by the interferometer LY2 and inputting the coordinate position Y to the Y servo operation unit 12Y. ing. Note that a feedforward operation using the derivative of the command position or the like may be added.

The Y1 / Y2 switching operation unit 12YY
Is an interferometer L used for calculating the coordinate position of the wafer stage 8 in the y direction according to the coordinate position of the wafer stage 8 in the x direction calculated based on the output of the interferometer LX.
It is set to switch between Y1 and interferometer LY2, and to switch the measurement position in the x direction. Whether or not the switching is performed is performed in accordance with the switching of the moving direction of the wafer stage 8 in the x direction, and when switching is performed, a predetermined switching process described later is set.

Outside the field of the projection optical system PL, an off-axis type wafer alignment system (not shown) for detecting the position of an alignment mark (not shown) or a reference mark plate on the wafer W is fixed. I have.

Next, the above interferometer LX and interferometer LY
1. The procedure for measuring the coordinate position of the wafer stage 8 using the position measuring device 10 having LY2 will be described. Here, an example in which the position of the wafer stage 8 in the y direction is measured while moving the wafer stage 8 in the x direction will be described. That is, as shown in FIG. 4, the wafer stage 8 moves from the center of the stroke to the position indicated by a dotted arrow x in the figure.
(B) from the Y1 measurement area in which only the coordinate position Y1 is obtained by the interferometer LY1, as shown in FIG. 4 (a). As shown in FIG. 4, only the coordinate position Y2 by the interferometer LY2 is obtained through the Y1 · Y2 measurement area where both the coordinate positions Y1 and Y2 are obtained by the interferometers LY1 and LY2, as shown in FIG. The switching process when moving to the Y2 measurement area will be described.

The alignment controller 12
Performs a so-called initialization operation of resetting the interferometers LX, LY1, and LY2 by using an origin reset sensor (not shown) previously set at a known position of the wafer stage 8, for example, at the center of a stroke. Shall be

The Y1 / Y2 switching operation unit 12YY
In the X-direction coordinate position X obtained by the interferometer LX, the position of the wafer stage 8 is always recognized in each of the above measurement regions, and the X-direction position command (X position command ), It is always recognized in which direction the wafer stage 8 is moving in the forward or reverse direction of the arrow.

First, the wafer stage 8 is moved to the position shown in FIG.
As shown in the figure, the positive direction in the x direction (the direction of the dotted arrow in the figure)
When the movement is started, the Y1 / Y2 switching operation unit 12YY that recognizes the Y1 measurement area is used as the interferometer L
The coordinate position Y1 based on Y1 is output as the coordinate position Y of the wafer stage 8 in the y direction.

Next, the wafer stage 8 corresponds to FIG.
As shown in the figure, the coordinate position Y2 obtained by the interferometer LY2 is immediately preset to the same measurement value as the coordinate position Y1 obtained by the interferometer LY1 as soon as it enters the Y1, Y2 measurement area. Usually, since the interferometer measurement position includes an air fluctuation error having a phase and an amplitude that differ depending on the measurement position, the interferometer LY
After the preset of 2, the difference of the coordinate position (Y
Calculate the average value ΔY of 2-Y1).

After this calculation, the value of the coordinate position Y2 by the interferometer LY2 is preset again with the value of (Y1 + ΔY). Thereafter, when the coordinate position Y of the wafer stage 8 is directly switched from the coordinate position Y1 to the coordinate position Y2 having the value of the coordinate position (Y1 + △ Y), vibration or instability due to discontinuity of the measurement position occurs. Therefore, after the next calculation is performed at a constant switching time T, switching to the coordinate position Y2 is performed.

That is, the above operation is performed by the following equation. Y = Y1 + (Y2-Y1) t / T (0 ≦ t / T ≦
1) Y: Coordinate position of wafer stage in y direction Y1: Coordinate position by interferometer LY1 Y2: Coordinate position by interferometer LY2 t: Switching time T: Switching time

By this operation, when the switching time t = 0, t / T = 0, so that Y = Y1. When the switching time t = T, t / T = 1, so that Y = Y1. Y
It becomes 2. That is, the coordinate position Y of the wafer stage 8 in the y direction at the switching time T is changed from the coordinate position Y1 based on the output of the interferometer LY1 used before the switching to the coordinate position Y2 based on the output of the interferometer Y2 used after the switching.
Since the value is gradually approached according to the time, the switching from the coordinate position Y1 to the coordinate position Y2 is performed smoothly.

After that, even if the wafer stage 8 enters the Y2 measurement area as shown in FIG. 4C, the coordinate position Y2 has already been switched to the coordinate position Y2. It is only necessary to output the position Y.

On the other hand, when the wafer stage 8 moves in the direction opposite to the above movement, that is, when the wafer stage 8 moves from the right side to the left side in FIG.
Switching from 2 to the coordinate position Y1 may be performed.

By the way, when the movement of the wafer stage 8 is Y
When starting from the 1 (or Y2) measurement area, stopping at the Y1 / Y2 measurement area, and returning again to the Y1 (or Y2) measurement area, when such an operation is known in advance by the position command in the x direction, In order to minimize the occurrence of the switching error, it is preferable to use an algorithm that does not perform the switching process.

The switching position, the position where the interferometer is preset at the time of switching, and the area where the averaging calculation of the air fluctuation is performed are always set to be the same in order to improve the reproducibility in the switching process.

By performing the switching process as described above, the wafer stage 8 can be moved in the x direction by the moving stroke L or more. In other words, the wafer W is moved in a step-and-scan manner through the movement of the wafer stage 8, and the image of the pattern of the reticle R illuminated by the exposure light of the illumination optical system 6 is projected onto the projection optical system P.
Exposure processing for sequentially projecting and transferring the wafer L through the wafer L is performed.

The length (L / 2) of the reflecting surface RY of the moving mirror MY in the x direction and the pair of laser beams BY1 and BY1, so that the interferometers Y1 and Y2 are not switched during the scanning exposure.
The interval of BY2 is defined. That is, the wafer stage 8 is set so as not to come to the switching position during the scanning exposure of one area, and the switching is performed immediately before performing the scanning exposure of the next area in order to minimize the influence of the switching on the exposure. It is set to be performed.

In the position measuring method, position measuring apparatus, and exposure apparatus of the present embodiment, the wafer stage 8 in the y direction is determined in accordance with the coordinate position X of the wafer stage 8 in the x direction measured based on the output of the interferometer LX. Switching between the interferometer LY1 and the interferometer LY2 for measuring the coordinate position of
Since the measurement position in the x direction is switched, the reflection surface RY shorter than the movement stroke L of the wafer stage 8 in the x direction.
Can be used to perform highly accurate position measurement in the y direction. Thus, the exposure position of the wafer W can be adjusted with high accuracy during the pattern transfer of the reticle R, and good overlay accuracy can be obtained. Further, by reducing the length of the reflecting surface RY, it is possible to reduce the cost of the apparatus and improve the performance of the movement control of the wafer stage 8.

The present invention includes the following embodiments. (1) Although a pair of interferometers LY1 and LY2 are provided to measure the coordinate position of the wafer stage 8 in the y direction, a plurality of interferometers are similarly installed in the x direction, and the switching process is performed for measurement. It does not matter. (2) Although a pair of interferometers LY1 and LY2 are provided to measure the coordinate position of the wafer stage 8 in the y direction, three or more interferometers may be provided. In this case, the interferometer switching process is sequentially performed according to the coordinate position of the wafer stage in the x direction.

(3) The alignment controller 1
In step 2, a process of performing coordinate correction in consideration of the distortion and the like of the reflecting surfaces RX and RY of the moving mirrors MX and MY detected separately may be added. (4) In the above-described exposure apparatus 1, the object to be subjected to the exposure processing is configured as a wafer. However, the present invention is not limited to this. For example, a reticle or a glass substrate used for a liquid crystal display may be used. Although the position measuring device is provided in the exposure device, the present invention is also applicable to a measuring device that measures the coordinate position of a pattern such as a mask or a wafer with high accuracy.

(5) Position measuring device 1 on wafer stage 8
However, the present invention is not limited to this. For example, a configuration provided on the reticle stage 7 or a configuration provided on both stages 7 and 8 may be used. (6) The movable mirror MX having the reflection surface RX is provided on the wafer stage 8 for measuring the coordinate position in the X direction, but is provided on the stage so as to reflect the laser beam BX incident from the x direction in the opposite direction. Other reflectors may be used as long as they are suitable. For example, a corner cube may be provided as a reflector.

(7) As the exposure apparatus, the reticle R and the wafer W are moved synchronously as in this embodiment, and the reticle R
In a step-and-scan (scanning) exposure apparatus that exposes the pattern of the reticle R, the pattern of the reticle R is exposed while the reticle R and the wafer W are stationary, and the wafer W is sequentially step-moved. The present invention can also be applied to a repeat type exposure apparatus. The type of the exposure apparatus is not limited to an exposure apparatus for manufacturing a semiconductor, and is, for example, an exposure apparatus for a liquid crystal that exposes a liquid crystal display element pattern to a square glass plate, or for manufacturing a thin film magnetic head. It can be widely applied to an exposure apparatus. Further, the present invention can 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 with each other without using the projection optical system PL.

[0043]

According to the present invention, the following effects can be obtained. (1) In the position measuring method according to the first aspect and the position measuring apparatus according to the fifth aspect, the position measuring method according to the second direction is performed in accordance with the coordinate position of the stage in the first direction measured based on the output of the first optical interferometer. Since the second light wave interferometer that measures the coordinate position of the stage is switched and the measurement position in the first direction is switched, even if a reflecting surface shorter than the movement stroke of the stage in the first direction is used, a highly accurate position in the second direction is used. Measurement can be realized. Also, when performing stage control using this position measuring method and position measuring device, the reflecting surface can be shortened with respect to the movement stroke,
It is also possible to set the movable part of the stage small,
The stage natural frequency can be increased, and as a result, excellent stage control performance such as positioning accuracy and followability can be obtained. Further, the shortening of the reflecting surface makes the manufacturing of the reflecting surface relatively easy, and the cost can be reduced.

(2) In the position measuring method according to the second aspect,
A predetermined switching time is provided when the second light wave interferometer is switched, and the measured value of the coordinate position of the stage in the second direction at the switching time is a measured value based on the output of the second light wave interferometer used before the switching. Since the measured value based on the output of the second light wave interferometer used after the switching is gradually made closer to the time, it is possible to prevent a large instantaneous fluctuation and to perform a smooth switching.

(3) In the position measuring method according to the third aspect,
Since the switching of the second light wave interferometer is performed according to the switching of the moving direction of the stage with respect to the first direction, for example,
Even if the stage has reached the switching position of the second lightwave interferometer, if the switching of the moving direction is performed, the second
By not switching the light wave interferometer, it is possible to prevent a measurement error due to the switching.

(4) In the position measuring method according to the fourth aspect,
Since the switching of the second light wave interferometer is always performed at a fixed coordinate position of the stage in the first direction, the positional environment at the time of the switching is the same, so that the switching reproducibility of the measurement position can be improved.

(5) In the exposure apparatus according to the sixth aspect, the alignment controller adjusts the exposure position of the substrate with respect to the pattern of the mask using the coordinate position of the stage obtained by the position measuring apparatus. Exposure processing can be performed accurately by accurate positioning.

(6) In the exposure apparatus according to claim 7, the length of the reflecting surface of the second reflector in the first direction and the plurality of lasers are set so that the switching of the second light wave interferometer is not performed during the scanning exposure. Since the interval between the beams is determined, the influence of the switching of the measurement position does not occur during the scanning exposure, and high-precision scanning exposure can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention and is a schematic configuration diagram for explaining a position measuring device in an exposure apparatus.

FIG. 2 is a view showing an embodiment of the present invention, and is a front sectional view in which an exposure apparatus main body is disposed in a chamber.

FIG. 3 is a diagram illustrating an embodiment of the present invention, and is a control block diagram for explaining an alignment controller.

FIG. 4 is a view showing an embodiment of the present invention, and is an explanatory view showing a method of measuring the position of a wafer stage in the order of steps;

FIG. 5 is a view showing a conventional example of the present invention, and is a schematic configuration diagram for explaining a position measuring means of a stage.

[Explanation of symbols]

R Reticle (mask) W Wafer (substrate) 7 Reticle stage (mask stage) 8 Wafer stage (substrate stage) 10 Position measuring device 11 Laser interferometer (first and second light wave interferometers) 12 Alignment controller BX, BY1, BY2 He-Ne laser beam MX moving mirror (first reflector) MY moving mirror (second reflector) RX reflecting surface RY reflecting surface LX, LY1, LY2 interferometer (first light wave interferometer, second
Light wave interferometer)

Claims (7)

[Claims] 1. A first reflector provided on a stage so as to reflect light incident from a first direction in a reverse direction, and reflects light incident from a second direction orthogonal to the first direction along the first direction. A first reflector for irradiating a laser beam to a second reflector provided on the stage so as to reflect in the opposite direction on the surface.
A method for measuring a coordinate position of a stage based on outputs of a light wave interferometer and a second light wave interferometer, wherein a plurality of second light wave interferometers are used to measure a first position of a reflection surface of the second reflector. Irradiating a plurality of laser beams to positions separated from each other in the direction, and measuring the first laser beam based on the output of the first lightwave interferometer.
A position measuring method, wherein a second light wave interferometer for measuring a coordinate position of a stage in a second direction is switched according to a coordinate position of the stage in a direction, and a measurement position in the first direction is switched. 2. A method according to claim 1, wherein a predetermined switching time is provided when the second light wave interferometer is switched, and a measured value of the coordinate position of the stage in the second direction at the switching time is used before the switching. 2. The position measurement method according to claim 1, wherein the measurement value based on the output of the second lightwave interferometer used after switching from the measurement value based on the output of the meter is set to a value gradually approached in accordance with time. 3. The position measuring method according to claim 1, wherein the switching of the second light wave interferometer is further performed in accordance with switching of a moving direction of the stage with respect to the first direction. 4. The position measuring method according to claim 1, wherein the switching of the second light wave interferometer is always performed at a fixed coordinate position of the stage in the first direction. . 5. A first light wave interferometer for irradiating a first reflector provided on a stage with a laser beam so as to reflect light incident from a first direction in a reverse direction, and a second light wave interferometer orthogonal to the first direction. Light incident from the first direction
A second reflector for irradiating a second reflector provided on the stage with a laser beam so as to reflect in a reverse direction on a reflecting surface along the direction;
A light wave interferometer; and a calculator for calculating a coordinate position of the stage in the first and second directions based on outputs of the first and second light wave interferometers, wherein the second light wave interferometer comprises: A plurality of laser beams are respectively radiated to a position spaced apart from each other in the first direction with respect to a reflection surface of the second reflector, and the arithmetic unit outputs an output of the first light wave interferometer. The second light wave interferometer used for calculating the coordinate position of the stage in the second direction is switched according to the coordinate position of the stage in the first direction calculated based on the first direction, and the measurement position in the first direction is switched. A position measuring device characterized by being set. 6. The position measuring device according to claim 5, wherein at least one of a mask stage for holding a mask and a substrate stage for holding a substrate onto which the pattern of the mask is transferred is provided. And an alignment controller for adjusting an exposure position of the substrate with respect to the pattern of the mask using a coordinate position of the stage. 7. A driving device for synchronously driving the mask stage and the substrate stage along the first direction in order to scan and expose one region on the substrate with the pattern of the mask, The first light wave interferometer is not switched during the scanning exposure so that the first light wave interferometer is not switched.
The exposure apparatus according to claim 6, wherein a length of a reflection surface of the second reflector in a direction and an interval between the plurality of laser beams are determined.