JP2001242269A - Stage device, stage driving method, exposure device and exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stage device, an exposure device, a stage driving method and an exposure method, simplifying device constitution by making a stage small and lightweight in the stage device, and dispensing with an encoder or the like exclusively used for the commutation of an electromagnetic force motor for driving the stage. SOLUTION: This stage device 100 is provided with the stage ST movable in a first direction (X-direction), the electromagnetic force motor 40 for driving the stage ST in the first direction, a laser interferometer system 20 for measuring the position of the stage ST, and a control means 50 for controlling the electromagnetic force motor 40. The control means 50 uses the measured value of the laser interferometer system 20 for the commutation of the electromagnetic force motor 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage device for measuring a position of a stage and driving the stage based on the measurement result, and a stage driving method. Further, it is suitable for use as a stage of an exposure apparatus used for manufacturing semiconductors and liquid crystals.

[0002]

2. Description of the Related Art Conventionally, for example, a semiconductor device, a liquid crystal display device, and an image pickup device (CCD, Charge Couple)
In the photolithography process in the manufacturing process of the d device and the thin-film magnetic head, an exposure apparatus is used to form a circuit pattern on a semiconductor layer or a metal wiring layer. In this exposure apparatus, a reticle or a photomask on which a circuit pattern is formed (hereinafter, collectively referred to as a reticle) is used. A reticle is placed on a reticle stage of an exposure apparatus, and a semiconductor wafer, a liquid crystal substrate, or the like (hereinafter, collectively referred to as a substrate) coated with a photosensitive agent such as a photoresist is placed on the substrate stage. Then, the circuit pattern formed on the reticle is transferred to the substrate.

In an exposure apparatus, in order to expose a pattern formed on a reticle to a predetermined position on a substrate, the position of a reticle stage or a substrate stage is measured, and each stage is driven and positioned based on the measurement result. Are doing.

[0004]

FIG. 8 is a diagram showing a stage in a conventional exposure apparatus. FIG. 8 is a plan view. A movable mirror MX is provided on one side of the stage ST movable in the XY plane along the Y direction, and a movable mirror MY is provided on one side along the X direction. I have. The movable mirrors MX and MY are installed substantially orthogonally. X of stage ST
The position in the direction is determined by the measurement axes X1 and X1 of the laser interferometer system with the measurement laser incident almost perpendicularly on the moving mirror MX.
2 and the position of the stage ST in the Y direction are measured by the measuring axis Y of a laser interferometer having a measuring laser which is incident almost perpendicularly on the moving mirror MY. The distance between the optical paths of the measurement axes X1 and X2 is a distance DX in the Y direction,
From the difference between the measured values of the measurement axes X1 and X2, the amount of rotation about the Z axis perpendicular to the XY plane can be obtained. Therefore, in this stage measurement, the stage S
Measurement of three degrees of freedom, that is, rotation components of the X in the X direction, the Y direction, and the θZ direction is realized by three measurement axes.

In such a configuration, the measuring mirrors X1, X2, and Y are always irradiated to the movable mirrors MX and MY, respectively, in all the areas of the maximum movement range of the stage ST in the X and Y directions. Need to be. Therefore, even if the stage ST moves in the XY plane, the dimensions of the movable mirrors MX and MY are set to be smaller than the movable range of the stage ST so that the measurement lasers of the measurement axes X1, X2, and Y of the laser interferometer system are continuously reflected. I needed to keep it big.

[0006] Therefore, in order to extend the movable range of the stage ST, large movable mirrors MX and MY are required, and the whole shape of the stage ST must be enlarged accordingly. Has become heavy, making it difficult to move the stage ST at high speed.

In order to solve such a problem, the number of measurement axes (for example, four) larger than the number of degrees of freedom of the position of the stage (for example, three degrees of freedom in the X, Y, and θZ directions) is changed by laser interference. The measurement laser of the second measurement axis in the first direction is provided on the movable mirror even if the measurement laser of the first measurement axis in the first direction is out of the measurement range of the movable mirror. The measurement range is set so that one of the measurement lasers on the measurement axis always enters the measurement range of the movable mirror. Then, when the movable mirror moves from the measurement range of the first measurement axis to the measurement range of the second measurement axis,
By setting the measurement value on the first measurement axis as the initial value of the second measurement axis, it has been possible to make the size of the movable mirror smaller than the movable range of the stage.

In the above exposure apparatus, in addition to the laser interferometer system for measuring the stage position for positioning the stage, the stage position is measured exclusively for the commutation of the electromagnetic force motor for driving the stage. Sensors such as linear encoders were provided.

These sensors can measure the position of the stage over the entire movable range of the stage, and need to be provided inside or near the electromagnetic force motor. Hereinafter, conventional commutation of an electromagnetic motor that drives a stage will be described. As a conventional technique relating to commutation of an electromagnetic motor for driving a stage, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 6-187042.

FIG. 9 is a diagram showing the configuration of a device in the vicinity of a conventional electromagnetic motor for driving a stage. In FIG.
A driving device 4 which is an electromagnetic force motor for driving the stage ST
In the vicinity of 0, optical linear encoders 91 and 92, an origin detector 93, and a drive control device 80 are provided.
The drive control device 80 includes a communication interface unit 81, an encoder signal processing unit 82, a thrust calculation unit 83, and a commutation processing unit 84.

The stage ST is movable along a guide 95 in the direction of arrow 94. The optical linear encoders 91 and 92 measure the position of the stage ST, where 91 is the moving side and 92 is the fixed side. Optical linear encoder 9
The measurement ranges 1 and 92 are the entire movable range of the stage ST along the guide 95. The origin detector 93 detects the origin of the stage ST. The driving device 40 is a stage S
T is driven. In this description, the driving device 40 is 2
A moving coil linear motor having phase coils CL1 and CL2 is used.

The optical linear encoder 92 outputs two signals SG1 and SG2. Signals SG1 and SG2
Are a sine wave signal and a cosine wave signal indicating an output voltage with respect to the movement amount of the stage ST. The origin detector 93 outputs an origin signal SG3.

The communication interface unit 81 receives a command based on the position of the stage ST measured by the above-described laser interferometer system from a control device of an exposure apparatus (not shown).
For example, a command to drive the stage ST to a predetermined position is received.

The encoder signal processing section 82 outputs the signal SG
1, SG2 and SG3 are processed to calculate a measured value of the stage position. The encoder signal processing unit 81 outputs the calculated measurement value to the thrust calculation unit 83.

The thrust calculation unit 83 sets a predetermined position instructed based on a command received from the control device (not shown) received via the communication interface unit 81 and a measured value of the position of the stage ST measured by the encoder. Stage S
The thrust for driving T is calculated, and the calculated thrust is output to the commutation processing unit 84.

The commutation processing unit 84 performs commutation of the driving device 40 based on the measured value of the stage position and the thrust. Since commutation is known, detailed description is omitted. In other words,
The commutation processing unit 84 determines the magnitude and direction of the current so as to obtain a thrust, and distributes the determined current to each of the two-phase coils CL1 and CL2 constituting the driving device 40. Due to this current, a driving force is generated by the coil, and the stage ST is driven.

Conventionally, as described above, in addition to the laser interferometer system for measuring the position of the stage for positioning the stage, an encoder dedicated to commutation or the like is provided inside or near a driving device for driving the stage. However, there is a problem that the device configuration becomes redundant.

According to the present invention, a stage apparatus, an exposure apparatus, and a stage relating thereto are provided in which the moving mirror is shortened to reduce the size and weight of the stage, and the apparatus configuration is simplified by eliminating the need for an encoder or the like dedicated to commutation. It is an object to provide a driving method and an exposure method.

[0019]

Means for Solving the Problems To solve the above problems, a description will be given with reference to FIGS. 1, 2, 4 and 7 showing one embodiment.
According to 0), a stage (ST) movable in a first direction (X direction), an electromagnetic force motor (40) for driving the stage (ST), and laser interference for measuring the position of the stage (ST) Meter system (20) and electromagnetic force motor (40)
Control means (50) for controlling the
0) is characterized in that the measured values of the laser interferometer system (20) are used for commutation of the electromagnetic motor (40).

The electromagnetic force motor (40) drives the stage ST in the first direction (X direction), the laser interferometer system (20) measures the position of the stage (ST), and the control means (50) The electromagnetic force motor (40) is controlled. Here, the control means (50) is a laser interferometer system (20)
Are used for commutation of the electromagnetic force motor (40).

For the positioning of the stage (ST), the measured values of the laser interferometer system for measuring the position of the stage (ST) are used for the commutation. Therefore, the entire movable area of the stage is used as a measurement area for commutation of the electromagnetic force motor (40), and there is no need to provide an encoder or the like for measuring the position of the stage (ST) in the stage device.

According to the stage apparatus (100) of the second aspect, the stage (ST) is movable in a second direction (Y direction) perpendicular to the first direction, and is provided with a laser interferometer system (20). ) Are a plurality of laser interferometers (Y) having measurable regions overlapping each other in the second direction (Y direction).
1, Y2), and the control means (50) controls the laser used for commutation when the stage (ST) is in the area (71) where the measurable areas of the plurality of laser interferometers (Y1, Y2) overlap. It is characterized in that the interferometer is switched.

When the position of the stage (ST) is measured by a plurality of laser interferometers (Y1, Y2) having a measurable area (71) overlapping each other in the second direction (Y direction), the control means ( 50) is an area (7) in which the measurable areas of the plurality of laser interferometers (Y1, Y2) overlap.
When there is a stage (ST) in 1), the laser interferometer used for commutation is switched from the currently used first laser interferometer to the second laser interferometer.

Thus, the laser interferometer used for commutation is switched to the second laser interferometer before the stage (ST) deviates from the measurement area of the first laser interferometer currently used for measurement. Accordingly, it is possible to prevent the measurement value of the laser interferometer from being used for commutation due to the movement of the stage (ST) and the displacement of the stage from the measurement area of the first laser interferometer.

According to the stage device (100) of the third aspect, the control means (50) further comprises a stage (S)
The laser interferometer used for commutation is switched according to the moving direction of T).

Thus, the control means (50) determines whether or not it is necessary to switch according to the position of the stage (ST) and the moving direction of the stage (ST). It is possible to switch the laser interferometer used for commutation.

According to the stage device (100), the control means (50) calculates the thrust for driving the electromagnetic force motor (40) based on the measured value of the position of the stage (ST). However, the commutation is performed based on the thrust and the measured value.

By performing commutation based on the thrust calculated by the control means (50) and the measured value by the laser interferometer system (20), the stage (ST) can be driven to a desired position. Become.

According to the stage apparatus (100), a plurality of laser interferometers (X1, X2, Y1, Y) are provided.
The measured value of 2) is taken in synchronously, and the control means (50)
It is sent to

A plurality of laser interferometers (X1, X2, Y1,
Control means (50) for synchronously taking in the measured value of Y2)
, It is possible to periodically input the measured value to the control means (50).

According to the present invention, there is provided an exposure apparatus (1000) for exposing a substrate (5) by projecting a pattern formed on a reticle onto the substrate (5), wherein the reticle or the substrate ( The stage device (100) according to any one of claims 1 to 5 is used for a stage (2, 4) on which the stage (5) is mounted.

The stage apparatus (100) according to any one of claims 1 to 5 can be used for one or both of the reticle stage (2) and the substrate stage (4) of the exposure apparatus (1000). This eliminates the need to provide an encoder or the like dedicated to the commutation of the electromagnetic force motors constituting the driving devices (8, 9) in one or both of the reticle stage driving device (8) and the substrate stage driving device (9). . The exposure system (1
000) can be simplified.

According to a seventh aspect of the present invention, there is provided a driving method for driving the stage (ST) using the electromagnetic force motor (40), wherein the laser interferometer (X1, X2, Y1, Y) is used.
Step (S1) of measuring the position of the stage (ST) using 2) and a laser interferometer (X1, X2, Y1, Y)
And (2) performing commutation of the electromagnetic force motor (40) using the measured value of (2).

Laser interferometer (X1, X2, Y1, Y2)
Is used to measure the position of the stage (ST), and the electromagnetic force motor (40) is commutated using the measured value. This makes it unnecessary to perform commutation using a measurement value obtained by an encoder or the like dedicated to commutation of the electromagnetic force motor (40).

According to the driving method of the eighth aspect, the stage (ST) includes a plurality of laser interferometers (X1, X2, Y1, Y1).
(S2) when it is within the measurable area (71) in (Y2).
3, Yes), the step of switching the laser interferometers (X1, X2, Y1, Y2) used for commutation (S
5) is further included.

A plurality of laser interferometers (X1, X2, Y1,
Stage (ST) in area (71) that can be measured in Y2)
When there is, by switching the laser interferometer (X1, X2, Y1, Y2) used for commutation,
Even when the stage (ST) moves from the measurement area of the first laser interferometer currently used for commutation to the measurement area of the second laser interferometer, the stage deviates from the measurement area of the first laser interferometer. It is possible to switch the laser interferometer used for commutation before.

According to the driving method of the ninth aspect, the step (S4) of switching the laser interferometer used for commutation according to the moving direction of the stage (ST).
5) is further included.

In the case where the position of the stage (ST) is measured by a plurality of laser interferometers (X1, X2, Y1, Y2) having mutually overlapping measurable areas (71),
In addition, when the stage (ST) is in the area (71) where the measurable area overlaps, the control means (50) needs to switch the laser interferometer used for commutation according to the moving direction of the stage (ST). It is possible to switch between laser interferometers used for commutation when it is determined whether or not there is, and when it is determined that switching is necessary.

According to the driving method of the tenth aspect, the step of calculating the thrust for driving the electromagnetic force motor (40) based on the measured value of the laser interferometer (X1, X2, Y1, Y2) ( S2) and a step of performing commutation based on the thrust and the measured value (S6).

The calculated thrust and laser interferometer (X1, X
(2, Y1, Y2), by performing commutation based on the measured values, the stage (ST) is moved to a desired position.
Can be driven.

According to the driving method of the eleventh aspect, the method further comprises the step of synchronously taking in the measured values of the plurality of laser interferometers (X1, X2, Y1, Y2). By synchronously capturing the measured values of the plurality of laser interferometers (X1, X2, Y1, Y2), it is possible to periodically perform processing using the measured values.

According to the twelfth aspect of the present invention, there is provided an exposure method for exposing a substrate (5) by projecting a pattern formed on a reticle onto the substrate (5). The stage (2, 4) on which a reticle or a substrate is mounted is driven by the stage driving method according to any one of (1) to (4).

A reticle stage driving device (8) and a substrate are provided by using the stage driving method according to any one of claims 7 to 11 for driving one or both of the reticle stage (2) and the substrate stage (4). It is not necessary to measure the position of the stage (ST) exclusively for commutation of the electromagnetic force motor constituting the stage driving device (9).

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a stage apparatus according to an embodiment of the present invention, an exposure apparatus using the same, and a stage driving method and an exposure method related thereto will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an exposure apparatus according to one embodiment of the present invention. The exposure apparatus 1000
It mainly comprises an illumination system 1, a reticle stage 2 on which a reticle (not shown) is mounted, a projection optical system 3, and a substrate stage 4 on which a substrate 5 is mounted.

The illumination system 1 includes an exposure light source (not shown), an elliptical mirror,
A shutter, fly-eye lens, condenser lens, etc. are provided. Using such a series of devices, averaging of exposure light and the like are performed.

The reticle stage 2 mounts a reticle (not shown). A circuit pattern is formed on the reticle. Exposure light from the illumination system 1 irradiates a pattern surface formed on a reticle mounted on a reticle stage 2. The projection optical system 3 converts a pattern on a reticle (not shown) illuminated by exposure light into a substrate stage 4 at a predetermined magnification.
The image is projected on the upper substrate 5.

The substrate stage 4 places the substrate 5 thereon. The substrate 5 is coated with a photosensitive agent. The projected pattern is exposed on the substrate 5. Reticle stage interferometer system 6 measures the position of reticle stage 2. Reflectors (not shown) are provided in the X and Y directions on the side surface of the reticle stage 2. The reticle stage interferometer system 6 irradiates a measurement laser to the side surface of the reticle stage,
By detecting the light reflected by the reflecting mirror, the position of the reticle stage 2 is measured. The substrate stage interferometer system 7 measures the position of the substrate stage 4. The operation of the substrate stage interferometer system 7 is the same as that of the reticle stage interferometer system 6.

The reticle stage driving device 8 and the substrate stage driving device 9 drive the reticle stage 2 and the substrate stage 4, respectively. The control device 10 controls components constituting the exposure apparatus 1000, such as the illumination system 1, the reticle stage 2, and the substrate stage 4. The stage device according to the present embodiment is suitable for the reticle stage 2 and the substrate stage 4 of the exposure apparatus 1000 described above. Hereinafter, the stage device will be described.

FIG. 2 is a diagram showing a schematic configuration of a stage device according to the present embodiment. Stage device 1 of the present embodiment
Reference numeral 00 includes a stage ST, a laser interferometer system 20, an interferometer control device 30, a drive device 40, and a control device 50.

The stage ST has a sample stage T on the stage surface.
And a movable mirror (not shown) on the side surface in the X and Y directions. A reticle and a substrate are placed on the sample table T. The stage ST can be driven by the driving device 40 in the X and Y directions. The driving device 40 includes an X direction driving device 40X that drives the stage ST in the X direction and a Y direction driving device that drives the stage ST in the Y direction.
A direction driving device 40Y is provided. The driving device 40 is an electromagnetic motor, for example, an AC linear motor, a DC brushless linear motor, or the like can be considered.

The laser interferometer system 20 includes a stage S
Measure the position of T. The laser interferometer system 20 includes a laser interferometer system 20X that measures the position of the stage ST in the X direction and a laser interferometer system 20Y that measures the position of the stage ST in the Y direction. Each of the laser interferometer systems 20X and 20Y includes a laser light source, a beam splitter, a beam bender, an interference unit, and the like (not shown), but the description is omitted here. In FIG.
The laser interferometer system 20X includes two laser interferometers, and the laser interferometer system 20Y includes two laser interferometers. Each laser interferometer is provided corresponding to each of the measurement axes X1, X2, Y1, and Y2 for measuring the position of the stage ST. In each of the measurement axes X1, X2, Y1, and Y2, a measurement laser from an interference unit (not shown) provided on each measurement axis detects reflected light reflected by a moving mirror (not shown).

The interferometer controller 30 converts the detection results (signals) of the measurement axes X1, X2, Y1 and Y2 of the laser interferometer system 20 into measured values (counts), and converts the measured values via the line 60. To the control device 50. The interferometer control device 30 includes interferometer counters 30X1, 30X2, 3
0Y1 and 30Y2 and communication interface unit 31
Is provided. Interferometer counters 30X1, 30X2, 30Y
1 and 30Y2 calculate the measured value of the position of the stage ST by counting the order of the interference fringes of the reflected light detected on the measurement axes X1, X2, Y1 and Y2, respectively.
The communication interface unit 31 transmits the measured value of the position of the stage ST to the control device 50 via the line 60. Here, the communication interface unit 31 may acquire the measurement values from the interferometer counters 30X1, 30X2, 30Y1, and 30Y2 in synchronization with each other and transmit the measurement values to the control unit 50.

The control device 50 controls the driving device 40 using the measured values received from the interferometer control device 30. Hereinafter, the device configuration of the control device 50 will be described. FIG.
FIG. 3 is a diagram showing a device configuration of a control device 50. FIG.
3A illustrates the configuration of the control device 50 when the driving device 40 does not have a commutation function, and FIG. 3B illustrates the configuration of the control device 50 when the driving device 40 has a commutation function.
Is shown.

As shown in FIG. 3A, the control device 50
Includes a communication interface unit 51, a switching processing unit 52, a drive control unit 53, and a commutation processing unit 54. The communication interface unit 51 receives a measurement value of the position of the stage ST from the interferometer control device 30 via the line 60.

The switching processing unit 52 determines whether or not it is necessary to switch the measurement axis used for commutation based on the received measurement value and the thrust described later. Is switched, and the measured value of the position of the stage ST is output to the commutation processing unit. If it is determined that there is no need to switch, the measurement value is output to the commutation processing unit 54 without switching the measurement axis.

When switching the measurement axis, the switching processing section 52 returns the interferometer counter that has not been used for the measurement. The procedure for resetting and switching the interferometer counter will be described later.

The drive control unit 53 calculates a thrust for driving the stage ST to a target position to be positioned based on the received measurement values and a control algorithm of the stage ST provided in advance, and the switching control unit 52 And outputs it to the commutation processing unit 54.

The commutation processing unit 54 distributes the current to each coil constituting the driving device 40 based on the input measured value of the position of the stage ST and the thrust for driving the stage ST.

Next, FIG. 3B will be described. FIG.
In (b), the driving device 40 includes a commutation processing unit 41. The function is the same as that of the commutation processing unit 54 described above. In this case, the control device 50 does not need to include the commutation processing unit 53. Therefore, the control device 50 outputs the measured value of the position of the stage ST and the calculation result of the thrust calculated by the drive control unit 53 to the drive device 40. The commutation processing unit 41 of the driving device 40 distributes current to each coil based on the measured value and the thrust. Thus, the commutation processing unit 41
Provided in the drive device 40 is also within the scope of the present invention.

FIG. 4 is a diagram showing the arrangement of the measurement axes of the laser interferometer system. In FIG. 4, Y of stage ST
A movable mirror MX is provided on one side along the direction, and a movable mirror MY is provided on one side along the X direction of the stage ST. The moving mirrors MX and MY are substantially orthogonal. The position of stage ST in the X direction is measured by measurement axes X1 and X2 of laser interferometer system 20X, and the position of stage ST in the Y direction is laser interferometer system 20Y.
Are measured by the measurement axes Y1 and Y2. The measurement axes X1 and X2 of the laser interferometer system 20X are arranged at a distance DX, and the measurement axes Y1 and Y2 of the laser interferometer system 20Y are arranged at a distance DY.

The moving mirror MX is provided for the laser interferometer system 20.
It reflects the measurement laser that enters from each of the X measurement axes X1 and X2. The moving mirror MY reflects the measurement laser incident from each of the measurement axes Y1 and Y2 of the laser interferometer system 20Y. The reflected light is detected on each of the measurement axes X1, X2, Y1, and Y2. Further, from the difference between the measurement values of the measurement axes X1 and X2 for measuring the position in the X direction, or from the difference between the measurement values of the measurement axes Y1 and Y2 for measuring the position in the Y direction, the rotation around the Z axis perpendicular to the XY plane is obtained. The rotation amount θZ can also be obtained.

The length of each of the movable mirrors MX and MY is set to LX
And LY, the area 70 where the position of the stage ST can be measured has a length of LY + DY in the X direction and LX +
A region 70 indicated by oblique lines having the length of DX is obtained. If the center of the sample table T is within the area 70 indicated by the oblique lines,
The position of the stage ST can be measured.

A cross-shaped area 71 indicated by a shaded line of the area 70 has a center of the sample table T in this area.
One or both of the position in the X direction and the position in the Y direction of the stage ST are regions (hereinafter, referred to as overlap regions) that can be measured by a plurality of measurement axes.

The procedure for returning and switching the measuring axis used for commutation will be described below. In this description, it is assumed that the laser interferometer system is a heterodyne system. In the heterodyne method, the position of the stage ST is measured by integrating the change in the absolute phase of the measured interference signal with respect to the reference signal. FIG. 5 is a diagram illustrating the return and switching of the measurement axis used for commutation.
FIG. 5 is a diagram of the stage ST viewed from a Z direction perpendicular to the XY plane. Assume that the stage ST in FIG. 5A moves in the Y direction and reaches the position shown in FIG. 5B. FIG.
In (a), measurement lasers of measurement axes X1, X2, Y1, and Y2 are incident on movable mirrors MX and MY. Therefore,
The stage ST is placed in the overlap area 71 in FIG.
(The center of the sample stage T). As a result of the movement of the stage ST in the direction of the arrow 75, as shown in FIG. 5B, it is assumed that the measurement axis of the measurement axis X1 has deviated from the movable mirror MX. That is, the stage ST (the center of the sample stage T) is located in the region 70 indicated by oblique lines in FIG. In this case, the commutation of the driving device 40 is performed using the measurement value of the measurement axis X2. Then, as a result of the stage ST further moving in the direction opposite to the arrow 75, FIG.
Returning to the state of (a), it is assumed that the measurement laser of X1 is incident on the moving mirror MX. Further, it is assumed that the stage ST advances in the direction opposite to the arrow 75, and the stage ST (the center of the sample table T) is moving to a region where the measurement axis can be measured only at X1. Once the measuring laser is disengaged from the moving mirror, the measured value converted from the signal of the measuring axis will not be correct. Therefore, before the measurement laser is switched to the measurement axis X1 that has deviated from the movable mirror, the initial value is calculated from the measurement value of the other measurement axis X2 that has not deviated from the movable mirror, and the measurement axis X1 is returned. Is required.

Hereinafter, a method for obtaining the initial value of the measurement axis X1 will be described. The measurement value L (X1) of the measurement axis X1 is obtained by Expression (1). L (X1) = L (X2) −DX · θZ + d (1) Here, L (X2) is a measured value of the measurement axis X2. DX
Is the distance between the measurement axes X2 and X1. θZ is the rotation angle of the stage ST about the Z axis. d is an offset term due to the orthogonality between the moving mirrors MX and MY, and is a constant value. here,
θZ is obtained from the measured values of the measurement axes Y2 and Y1 according to equation (2).

ΘZ = {L (Y2) −L (Y1)} / DY (2) where L (Y2) is a measured value of the measurement axis Y2, and L (Y1)
Is a measured value of the measurement axis Y1. DY is the measurement axis Y1
And Y2. θZ is the value of stage ST (sample stage T
Is measured when the measurement area of the measurement axes Y1 and Y2 is in the overlap area where the measurement axes overlap. Stage ST
ΘZ is a constant value unless is rotated about the Z axis. When the stage ST is not rotating at all around the Z axis, the difference between L (Y2) and L (Y1) is 0 (zero), and thus θZ is 0 (zero). By substituting equation (2) into equation (1), equation (3) is obtained.

L (X1) = L (X2) − (DX / DY) · {L (Y2) −L (Y1)} + d (3) From the expression (3), the measured value of the measurement axis X1 is obtained. Calculate L (X1). Next, based on the calculated L (X1), based on the following equations (4) and (5), an estimated value of the order N and the phase difference ε which is a fraction of the interference of the measurement axis X1 is obtained.

N (X1) = g {L (X1) / (λ / m)} (4) ε = L (X1) / (λ / m) −N (X1) (5) Here, g {X} is a function that gives the largest integer not exceeding X. λ is the wavelength of the measurement beam. m is the number of turns of the optical path of the measurement beam.

Subsequently, the estimated values of N and ε and the measurement axis X
The initial value is determined from the absolute phase φ of 1. Here, the absolute phase φ is the phase difference between the reference signal and the measurement signal actually detected on the measurement axis.

First, N ′ is calculated by comparing the estimated value ε of the phase difference with the absolute phase difference φ. This comparison is performed for verification when the phase difference ε is close to 0 (zero) or 2π, because the estimated order may be shifted within a range of ± 1.

FIG. 6 shows the estimated phase difference ε and the absolute phase difference φ.
It is a figure explaining comparison with. This comparison will be described with reference to FIG. 6 (a) to 6 (c),
The horizontal axis indicates the phase in the range of interference orders k = N-1, k = N, and k = N + 1. The phase changes by 2π within the first order. FIG.
(A) when the absolute value of the difference between the actual absolute phase difference φ and the estimated phase difference ε is smaller than π (when | φ−ε | <π)
Is shown. In this case, since the absolute phase difference is within the order N, the order of the interference is N as the estimated value, and the set value N ′ = N. FIG. 6B shows a case where the value obtained by subtracting the estimated value ε of the phase difference from the actual absolute phase difference φ is larger than π (when φ−ε> π). In this case, since the absolute phase difference φ is within the order N−1, the set value N ′ is N ′ = N−1. FIG.
(C) shows a case where the value obtained by subtracting the estimated value ε of the phase difference from the actual absolute phase difference φ is smaller than −π (when φ−ε <−π). In this case, since the absolute phase difference φ is within the order N + 1, the set value N ′ is N ′ = N + 1.

The initial value R is calculated by substituting N ′ obtained as described above into the equation (6). R = M × N ′ + M (φ / 2π) (6) where M indicates the measurement resolution.

The initial value R is obtained as described above, and the measurement axis X1 is returned by using the obtained initial value R.
The measurement axis used for commutation of the driving device 40 is switched.

The procedure of commutation of the stage driving method according to the present embodiment will be described below. FIG. 7 is a flowchart illustrating a procedure of commutation performed by control device 50. In this description, as shown in FIG. 3A, the control device 50
4 will be described. However, the control device 50
Instead, the driving device 40 is
The same applies to the case of having.

First, the control device 50 receives a measurement value of the position of the stage ST measured using the laser interferometer system 20 via the communication interface unit 51 (step S1). The drive control unit 53 of the control device 50 determines a target position of the stage ST based on the received measurement value and a control algorithm of the stage ST provided in advance, and furthermore, a thrust for driving the stage ST to the target position. Is calculated. Further, the drive control unit 53 outputs the determined target position and the calculated thrust to the switching control unit 52 and the commutation processing unit 54 (Step S2).

The switching control unit 52 of the control device 50 determines whether or not the stage ST (the center of the sample table T) is in the overlap area 71 for each of the X direction and the Y direction (step S3). . Here, the switching control unit 52
Which area in the measurable area 70 is the overlap area 7
1 is provided in advance. The switching control unit 52 makes the determination in step S3 based on the information regarding the overlap area 71 and the received measurement value of the position of the stage ST.

When it is determined that the stage ST (the center of the sample stage T) is not within the overlap area 71 (No at Step S3), the switching control unit 52 does not need to switch the measurement axis used for commutation. Therefore, the switching control unit 52 outputs the measured value of the position of the stage ST to the commutation processing unit 54 without performing the switching process. The commutation processing unit 54 performs commutation based on the thrust and the like calculated by the drive control unit 53 and the measured value of the position of the stage ST (step S6).

When it is determined that the stage ST (the center of the sample stage T) is within the overlap area 71 (Step S3, Yes), the switching control unit 52 further performs the following for each of the X direction and the Y direction. It is determined whether or not the stage ST (the center of the sample stage T) is out of the measurement area of the first measurement axis currently used for measurement and is moving to the measurement area of the second measurement axis (step S4). The switching control unit 52 makes the determination in step S4 based on the measured value of the position of the stage ST and the moving direction of the stage ST indicated by the thrust output from the drive control unit 53. For example, in FIG. 4, as a result of the stage ST moving in the positive direction in the Y direction from the measurement area of the measurement axis X1, the stage S moves to the overlap area in the X direction (between the measurement axis X1 and the measurement axis X2).
The case where there is T (the center of the sample stage T) will be described. In this case, the measurement axis currently used for measuring the position of the stage ST is X1, but if the stage ST (the center of the sample stage T) moves further by a predetermined distance in the positive Y direction, the measurement axis It deviates from the measurement area of X1 and moves to the measurement area of the measurement axis X2. The switching control unit 52 includes a stage S
Based on the current position of the stage ST indicated by the measured value of the position T and the moving direction and moving distance of the stage ST indicated by the thrust outputted by the drive control unit 53, the stage is moved by the distance indicated in the direction indicated by the thrust. When ST is driven from the current position, it can be determined whether or not the stage ST (the center of the sample stage T) moves out of the measurement area of the measurement axis X1 and moves to the measurement area of the measurement axis X2.

If it is determined that the stage ST does not deviate from the measurement area of the first measurement axis currently used for measurement (step S4, No), the switching control unit 52 does not need to switch the measurement axis used for commutation. Absent. Therefore, the measurement value of the position of the stage ST is output to the commutation processing unit 54 without performing the switching process. The commutation processing unit 54 performs commutation based on the thrust and the like calculated by the drive control unit 53 and the measured value of the position of the stage ST (step S6). Note that the commutation performed in the present invention is performed in the same manner as in the related art, and thus the description is omitted.

When it is determined that the stage ST has deviated from the measurement area of the first measurement axis currently used for measurement and is moving to the measurement area of the second measurement axis (step S4, Y
es), the switching control unit 52 returns the second measurement axis as described above, and switches the measurement axis used for commutation from the first measurement axis to the second measurement axis (Step S).
5). After the switching, the second measurement axis is used for commutation. Further, the switching control unit 52 controls the stage S
The measured value of the position of T is output to the commutation processing unit 54.

The commutation processing unit 54 performs commutation based on the measured value of the position of the stage ST, the target position for positioning the stage ST, and the thrust for driving the stage ST to the target position (step S6). The above procedure is repeated at a constant cycle until the positioning of the stage ST is completed.

The function of control device 50 can be realized by an electronic circuit or by software. When the function of the control device 50 is realized by software, for example, a RAM (Ra
ndom Access Memory), ROM (R
internal storage devices such as e.g.
HD (Hard Disk) and FD (Floppy)
Disk (MD) (Magnetic Disk);
CD (Compact Disk) and MO (Magn)
An external storage device such as an optical disk such as an ETO (optical disc) and a magnetic tape is conceivable. When the control device 50 is connected to a network, the control device 50 may receive the program from a host computer or the like via the network.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, in the above embodiment, the order of interference is determined by comparing the absolute phase difference and the estimated value of the phase difference in the heterodyne laser interferometer system, and the initial value of the measurement axis is calculated. The procedure for switching the measurement axis to be used has been described. However, the present embodiment is also applicable to a case where a measured value of another measuring axis is used as an initial value.
Further, the present invention is also applicable to a homodyne type laser interferometer system.

For example, in the above embodiment, X
Although the directional laser interferometer system and the Y-directional laser interferometer system have been described as having separate laser light sources, if the amount of measurement laser incident on each measurement axis can be maintained within the light receiving range of each measurement axis, 1 It is also possible to use the light emitted from one of the laser light sources by dividing the light into all axes.

Further, for example, in the above embodiment, the setting of the initial value of one of the measurement axes in the X direction when one of the measurement axes in the X direction comes off the movable mirror has been described. Can be applied in the same manner even when is displaced from the movable mirror. Further, in the above-described embodiment, two measurement axes are prepared in the X direction and the Y direction, but the present invention can be applied to more axes.

For example, as an exposure apparatus, LC
The present invention can also be applied to an exposure apparatus for D, a semiconductor element, an image pickup element (CCD or the like), a reticle for an original plate, a thin film magnetic head, and the like. Further, for example, an exposure apparatus to which the stage device according to the above embodiment is applied can be applied by any of a step-and-repeat method and a scanning method. Step
In the AND repeat type projection exposure apparatus, the X stage and the Y stage move by a predetermined distance, and the pattern is exposed on the exposure area. On the other hand, in the scanning projection exposure apparatus, the reticle and the X stage and the Y stage move synchronously, and the pattern is exposed on the exposure area. The projection optical system of the scanning type exposure apparatus includes an inverted reduction system and an equal size erect erect image system, and can be applied to any of the projection optical systems.

Further, for example, as an exposure apparatus to which the stage apparatus according to the above-described embodiment is applied, a high-pressure / high-pressure mercury lamp exposure apparatus, an ArF exposure apparatus, an EB exposure apparatus, vacuum ultraviolet light such as F ₂ laser light (wavelength 157 nm), or the like. VUV exposure apparatus that uses as illumination light for exposure, wavelength 5 to 15n
An exposure apparatus using a charged particle beam, such as an EUV exposure apparatus using m light as exposure illumination light, an X-ray exposure apparatus, an ion beam exposure apparatus, and the like can be considered.

Further, an illumination optical system and a projection optical system (or an electronic optical system) composed of a plurality of lenses are incorporated in the exposure apparatus main body to perform optical adjustment, and a reticle stage (reticle) to which the stage apparatus according to the present embodiment is applied. The exposure apparatus of each of the above embodiments can be manufactured by attaching the exchange mechanism) and the substrate stage to the exposure apparatus main body, connecting wirings and pipes, and further performing overall adjustment (electrical adjustment, operation confirmation, and the like). 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.

[0090]

According to the present invention, it is possible to realize a stage device in which the size of the movable mirror is smaller than the moving range of the stage and the device configuration is simple.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of an exposure apparatus.

FIG. 2 is a diagram showing a schematic configuration of a stage device.

FIG. 3 is a diagram showing a device configuration of a control device.

FIG. 4 is a diagram showing an arrangement of measurement axes of the laser interferometer system.

FIG. 5 is a diagram illustrating return and switching of a measurement axis used for commutation.

FIG. 6 is a diagram illustrating a comparison between an estimated phase difference value ε and an absolute phase difference φ.

FIG. 7 is a flowchart illustrating a commutation procedure.

FIG. 8 is a diagram showing a stage in a conventional exposure apparatus.

FIG. 9 is a diagram showing a device configuration in the vicinity of an electromagnetic motor driving a conventional stage.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Illumination system 2 Reticle stage 3 Projection optical system 4 Substrate stage 5 Substrate 6 Reticle stage interferometer system 7 Substrate stage interferometer system 8 Reticle stage drive 9 Substrate stage drive 10 Control device 20, 20X, 20Y Laser interferometer system 30 Interferometer control device 31, 51 Communication interface unit 30X1, 30X2, 30Y1, 30Y2 Interferometer counter 40, 40X, 40Y Drive device 41, 54 Commutation processing unit 50 Control device 52 Switching control unit 53 Drive control unit 60 Line 70 Measurement possible Area 71 Overlap area 75 Arrow 100 Stage device 1000 Exposure device DX, DY Distance MX, MY Moving mirror ST Stage T Sample table X1, X2, Y1, Y2 Measurement axes

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/68 H01L 21/30 503A

Claims (12)

[Claims] A stage movable in a first direction; an electromagnetic motor for driving the stage in the first direction; a laser interferometer system for measuring a position of the stage; Control means for controlling, wherein the control means uses the measured value of the laser interferometer system for commutation of the electromagnetic force motor. 2. The method according to claim 1, wherein the stage is movable in a second direction perpendicular to the first direction, and wherein the laser interferometer system includes a plurality of lasers having mutually overlapping measurable regions in the second direction. An interferometer, the control means, when the stage is in an area where the measurable areas of the plurality of laser interferometers overlap,
The stage apparatus according to claim 1, wherein a laser interferometer used for the commutation is switched. 3. The stage apparatus according to claim 2, wherein said control means switches a laser interferometer used for said commutation according to a moving direction of said stage. 4. The control means according to the measurement value,
The stage apparatus according to any one of claims 1 to 3, wherein a thrust for driving the electromagnetic force motor is calculated, and the commutation is performed based on the thrust and the measured value. . 5. The stage apparatus according to claim 2, wherein the measured values of the plurality of laser interferometers are taken in synchronously and sent to the control means. 6. An exposure apparatus for exposing a substrate by projecting a pattern formed on a reticle onto the substrate, wherein the stage on which the reticle or the substrate is placed is mounted on the exposure apparatus. An exposure apparatus using the stage apparatus described in the above. 7. A method for driving a stage using an electromagnetic force motor, the method comprising: measuring a position of the stage using a laser interferometer; Performing commutation of the force motor. 8. The stage drive according to claim 7, further comprising a step of switching a laser interferometer to be used for the commutation when the stage is within an area that can be measured by a plurality of laser interferometers. Method. 9. The stage driving method according to claim 7, further comprising a step of switching a laser interferometer used for the commutation according to a moving direction of the stage. 10. The method further comprising: calculating a thrust for driving the electromagnetic force motor based on the measured value; and performing the commutation based on the thrust and the measured value. The stage driving method according to claim 7, wherein: 11. The stage driving method according to claim 8, further comprising the step of synchronously capturing the measured values of the plurality of laser interferometers. 12. An exposure method for exposing the substrate by projecting a pattern formed on the reticle onto the substrate, wherein the reticle or the reticle is formed by the stage driving method according to claim 7. An exposure method comprising driving a stage on which a substrate is mounted.