JP2003197502A - Measuring method and exposing method, aligner, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely measure a difference in position error of an object as it moves. <P>SOLUTION: A reticle microscope (observation area 52RA, 52RB) is used to successively observe a plurality of mark pairs on a reticle R and a pair of reference marks on a reference mark plate on a wafer stage, and to measure a positional difference of the respective marks to the reference mark while it moves on a reticle stage RST in Y-axis direction. The positional difference of the respective marks is used to obtain a relationship between the Y-axis direction position of the reticle R and the positional difference. Thus, a difference in position of the reticle R varying as an object according to its movement in Y-axis direction can be measured surely. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measurement method, an exposure method, an exposure apparatus, and a device manufacturing method, and more specifically, to position information of an object according to the moving position of a movable body on which the object is placed. The present invention relates to a measuring method for measuring, an exposure method using the measuring method, an exposure apparatus suitable for carrying out the exposure method, and a device manufacturing method using the exposure apparatus.

[0002]

2. Description of the Related Art A substrate on which a photomask or reticle (hereinafter referred to as "reticle") pattern is coated with a photosensitizer when manufacturing a semiconductor device, a liquid crystal display device, a thin film magnetic head, or the like by a photolithography process. A projection exposure apparatus for transferring onto a (wafer, glass plate, etc.) is used. A conventional projection exposure apparatus is a step-and-repeat type reduction projection exposure apparatus that sequentially moves each shot area of a wafer into an exposure field of a projection optical system and sequentially transfers a reticle pattern to each shot area. (So-called steppers) were often used.

On the other hand, in recent years, patterns are becoming finer in semiconductor devices and the like, and therefore, it is required to enhance the resolution of the projection optical system. Methods for increasing the resolution include methods such as shortening the wavelength of exposure light or increasing the numerical aperture of the projection optical system. However, it has become difficult to maintain the imaging performance (distortion, field curvature, etc.) at a predetermined accuracy over the entire exposure field. In view of this point, the so-called slit scan method or step and
A scanning type exposure apparatus such as a scanning method is becoming mainstream.

In this scanning type exposure apparatus, a reticle and a wafer are scanned relatively synchronously with respect to a rectangular or arcuate illumination area (hereinafter referred to as a "slit-shaped illumination area") while the reticle is being scanned. Pattern is transferred onto the wafer. Therefore, if a pattern having the same area as that of the stepper is transferred onto the wafer, the exposure field of the projection optical system in the scanning exposure apparatus can be made smaller than that of the stepper, and the accuracy of the imaging performance within the exposure field can be improved. Easy to improve.

[0005]

Generally, in a scanning exposure apparatus, the positions of a wafer stage and a reticle stage are measured by a laser interferometer capable of highly accurate position measurement, and controlled based on the measurement result. ing. Therefore, for example, when there is an error in the reticle stage coordinate system defined by the measurement axis of the laser interferometer, or when there is an error in the moving surface (running surface) of the reticle stage, scanning of the reticle stage (reticle) is performed. Position errors (including rotation errors) of the reticle that fluctuate depending on the position in the direction occur, but it is difficult to measure these position errors with a laser interferometer. As a result, the positional error of the reticle, which varies depending on the position of the reticle stage in the scanning direction, causes distortion of the transferred image of the reticle pattern transferred onto the wafer.

The present invention has been made in view of the above points, and a first object thereof is to reliably measure a position error of an object which fluctuates depending on a moving position of a movable body on which the object is placed. It is to provide a measurement method capable of performing the measurement.

A second object of the present invention is to provide an exposure method capable of reducing the distortion of the transferred image of the pattern.

A third object of the present invention is to provide an exposure apparatus capable of reducing the distortion of the transferred image of the pattern.

A fourth object of the present invention is to provide a device manufacturing method capable of improving device productivity.

[0010]

According to a first aspect of the present invention, a movable body (eg, RS) on which an object (eg, R) is placed.
T) is a measuring method for measuring the position information of the object that varies according to the moving position, wherein a plurality of first marks (29) are arranged on the movable body at predetermined intervals in the first axis direction.
_{1 to} 29 _n or 30 ₁ to 30 _n ) a first step of sequentially measuring each position information while moving the object along the first axis direction; and the position information of each of the first marks. A second step of calculating a component in the first axis direction and obtaining a relationship between the component of the position information in the first axis direction and the position of the object in the first axis direction based on the calculation result. It is a measuring method.

Here, the term "plurality of first marks arranged on a movable body" includes both a mark existing on the movable body and a mark existing on an object placed on the movable body. Is.

According to this, the position information of each of the plurality of first marks arranged on the movable body at a predetermined interval in the first axis direction is sequentially measured while moving the movable body along the first axis direction. (First step). Next, a component in the first axis direction of the measured position information for each first mark is calculated,
Based on the calculation result, the relationship between the component in the first axis direction of the position information of each of the plurality of first marks and the position of the movable body (or the object) in the first axis direction is obtained (second step). Therefore, by measuring the position error with respect to the design value or the reference position as the position information of each first mark,
Object (and movable body) according to the position of the movable body in the first axis direction
It becomes possible to measure the position error in the direction of the first axis.

In this case, as in the measuring method according to the second aspect, the component of the position information of each of the first marks in the second axis direction orthogonal to the first axis direction is calculated, and the calculation result is obtained. Thirdly, a relationship between at least one of the component of the position information in the second axial direction and the amount of rotation of the movable body (or object) and the position of the movable body (or object) in the first axial direction is obtained based on the third The method may further include steps.

In the measuring method according to claim 1,
As in the measuring method according to claim 3, on the movable body,
A plurality of second marks (30 ₁ to 30 _n or 29 _{1 to} 29 _n ) are further arranged at the predetermined intervals in the first axis direction,
In the first step, position information of each of the plurality of second marks is measured in a state where the object is at the same position as when measuring the position information of each of the first marks, and the object is at the same position. Sometimes the difference in the component in the first axial direction of the position information between the first mark and the second mark forming the set in which the position information is measured is calculated for each set, and the calculated result is Based on the rotation amount of the movable body (or object) and the first amount of the movable body (or object)
A third step of obtaining the relationship with the axial position can be further included.

In the measuring method according to claim 1,
As in the measuring method according to claim 4, on the movable body,
A plurality of second marks are further arranged at the predetermined intervals with respect to the first axis direction, and in the first step, position information of each of the plurality of second marks is set at the time of measuring the position information of each of the first marks. The position information of each of the first mark and the second mark that forms a set in which the position information is measured when the object is in the same position is measured. The difference between the components in the direction of the second axis orthogonal to the first axis is calculated for each set,
The method may further include a third step of obtaining the expansion / contraction amount of the object (or the movable body) in the second axis direction based on the average value of the calculation results.

The invention according to claim 5 is the first object (R).
An exposure method for transferring a pattern formed on a second object (W) onto a movable body on which the first object is placed by the measurement method according to claim 1. Measuring position information that varies according to the moving position of the movable body in the first axis direction using a plurality of marks of the first mark;
While synchronously moving the object and the second object in the first axis direction, at least one of the relative position, speed, and orientation of the first object and the second object is finely determined based on the measurement result. An exposure method including the step of adjusting and transferring the pattern.

According to this, by the measuring method according to any one of claims 1 to 3, a plurality of marks on the movable body on which the first object is placed are used to measure the movable body in the first axial direction. Positional information that varies according to the moving position of the is measured. here,
For example, the position information that changes according to the moving position of the movable body in the first axis direction is, for example, the mark, the first object, the first axis direction component of the position error of the movable body, the second axis direction component, and the first object. Alternatively, rotation of a movable body may be used.

Then, while the first object and the second object are synchronously moved in the first axis direction, the measurement result (for example, position information (mark, mark, which changes according to the moving position of the first object in the first axis direction, The first object and the second object based on measurement results of the first axis direction component, the second axis direction component of the position error of the first object or the movable body, and the rotation of the first object or the movable body). The pattern is transferred by finely adjusting at least one of the relative position, speed, and orientation of the pattern. Therefore,
A magnification error in the synchronous movement direction of the pattern, a position error in a direction orthogonal to the synchronous movement direction of the pattern, or a rotation error according to the position of the movable body on which the first object on which the pattern is formed is placed in the synchronous movement direction. It is possible to suppress the distortion of the transfer image of the pattern on the second object due to the above.

The invention according to claim 6 is the first object (R).
It is an exposure method which transfers the pattern formed in the 2nd object (W) via a projection optical system (PL), Comprising: By the measuring method of Claim 4, The said 2nd axial direction of the said 1st object. Measuring the amount of expansion and contraction of the pattern image; adjusting the magnification of the pattern image based on the measurement result; and moving the first object and the second object synchronously in the first axis direction while increasing the magnification. And a step of transferring the adjusted pattern image to the second object.

According to this, the expansion / contraction amount of the first object in the second axis direction is measured by the measuring method according to the fourth aspect.
Prior to exposure, the magnification of the pattern image is adjusted based on the measurement result. Then, the pattern image with the adjusted magnification is transferred to the second object while the first object and the second object are synchronously moved in the first axis direction. Therefore, it is possible to suppress the distortion of the transferred image of the pattern on the second object due to the magnification error.

The invention according to claim 7 is the first object (R).
And a second object (W) are synchronously moved in the first axis direction to transfer a pattern existing on the first object to the second object via a projection optical system (PL). A first movable body (15) on which the first object is mounted; a second movable body (32) on which the second object is mounted; marks (29 ₁ ...) existing on the first movable body 29 _n or 30 ₁ to 30 _n )
A mark detection system (54A or 54B) for detecting the position; and a first position measuring device (16) for measuring the position of the first movable body.
A second position measuring device (48) for measuring the position of the second movable body, and; while moving the first movable body along the first axial direction based on the output of the first position measuring device. ,
A measurement control device (2) that sequentially measures position information of each of a plurality of first marks arranged on the first movable body at predetermined intervals in the first axis direction by using the mark detection system.
0) and; on the basis of the measured position information for each of the first marks, the amount of expansion and contraction of the first movable body in the first axial direction according to the position of the first movable body in the first axial direction. The resulting magnification, the amount of positional deviation in the direction of the second axis orthogonal to the first axis,
And a computing device (20) for computing correction information for correcting at least one of the rotation amount; and, at the time of transferring the pattern, the first movable body and the first movable body based on the outputs of the first and second position measuring devices. An exposure apparatus including: a stage control device (20) for synchronously moving the second movable body in the first axis direction and finely adjusting the moving state of the first movable body based on the calculation result of the calculation device. Is.

According to this, by the measurement control device, the first
Position information of each of the plurality of first marks arranged on the first movable body at predetermined intervals in the first axial direction while moving the first movable body along the first axial direction based on the output of the position measurement device. Are sequentially measured using a mark detection system. Then, the computing device calculates the magnification based on the measured position information of each first mark, which is caused by the expansion / contraction amount of the first movable body in the first axial direction according to the position of the first movable body in the first axial direction, First
Correction information for correcting at least one of the amount of positional deviation and the amount of rotation in the second axis direction orthogonal to the axis is calculated. Then, when the pattern is transferred by the stage control device, the first movable body and the second movable body are synchronously moved in the first axis direction based on the outputs of the first and second position measuring devices, and the arithmetic operation of the arithmetic device is performed. The moving state of the first movable body is finely adjusted based on the result. As a result, the magnification due to the amount of expansion and contraction of the first movable body in the first axial direction according to the position of the first movable body in the synchronous movement, the position in the second axial direction orthogonal to the first axis. At least one of the shift amount and the rotation amount is corrected, and the distortion of the transfer image of the pattern transferred to the second object is effectively suppressed. In particular, the magnification due to the expansion / contraction amount of the first movable body in the first axial direction according to the position of the first movable body in the first axial direction, the amount of positional deviation in the second axial direction orthogonal to the first axis, and the rotation. When all the amounts are corrected, the distortion of the transferred image of the pattern can be suppressed most effectively.

In this case, as in the exposure apparatus according to claim 8, the correction information is such that the correction information corresponds to the position of the first movable body in the first axial direction. In the case of the information for correcting the magnification due to the expansion / contraction amount, the stage control device outputs the speed of at least one of the first and second movable bodies at the time of the synchronous movement to the output of the first measurement device. Fine adjustment can be made accordingly.

Alternatively, as in the exposure apparatus according to the ninth aspect, the correction information is information for correcting the positional deviation amount in the second axial direction according to the position of the first movable body in the first axial direction. In some cases, the stage controller finely adjusts the position of at least one of the first and second movable bodies in the second axial direction during the synchronous movement according to the output of the first measuring device. Can be

Alternatively, as in the exposure apparatus according to claim 10, the correction information is information for correcting the rotation amount of the first movable body according to the position of the first movable body in the first axial direction. In some cases, the stage control device may finely adjust the relative rotation amount of the first and second movable bodies during the synchronous movement according to the output of the first measuring device. .

In each of the exposure apparatuses described in claims 7 to 10, as in the exposure apparatus described in claim 11, the first
A plurality of second marks (30 ₁ to 30 _n or 29 _{1 to} 29 _n ) are further arranged on the movable body at the predetermined intervals in the first axis direction, a pair of the mark detection systems is provided, and the measurement control is performed. The device sequentially measures the position information of each of the plurality of first marks on the first movable body using the one mark detection system, and at the same time, calculates the position information of each of the plurality of second marks. Each position of the first mark and the second mark forming a set in which the position information is measured when the first movable body is at the same position and is sequentially measured using the other mark detection system. The difference of the component of the information in the second axis direction orthogonal to the first axis is calculated for each set, and the expansion / contraction amount of the first movable body in the second axis direction is calculated based on the average value of the calculation results. Further obtain the correction value of the resulting magnification, Prior to the transfer of the turn, a correction device (20, 49) for correcting the magnification of the pattern image based on the correction value of the magnification caused by the expansion / contraction amount of the first movable body in the second axis direction is further provided. Can be

In each of the exposure apparatuses described in claims 7 to 11, as in the exposure apparatus described in claim 12, the position information is information of a position error with respect to the reference mark on the second movable body, The mark detection system may be a system that detects the mark existing on the first movable body and the reference mark via the projection optical system.

According to a thirteenth aspect of the present invention, there is provided a device manufacturing method including a lithographic step, wherein in the lithographic step, exposure is performed using the exposure apparatus according to any one of the seventh to twelfth aspects. And a device manufacturing method.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
~ It demonstrates based on FIG. 9 (C).

FIG. 1 shows an exposure apparatus 10 according to one embodiment.
The 0 configuration is shown schematically. This exposure apparatus 100
Is a step-and-scan scanning exposure apparatus (so-called scanning stepper).

The exposure apparatus 100 includes an illumination system 12 including an exposure light source and a reticle R as a first object (and a mask).
Holding reticle stage RST, projection optical system PL,
It is provided with a wafer stage WST as a substrate stage on which a wafer W as a second object (and a substrate) is mounted, and a control system for these.

The illumination system 12 is, for example, Japanese Patent Laid-Open No. 6-34.
As disclosed in Japanese Unexamined Patent Publication No. 9701 and the like, an illumination uniformizing optical system including a light source, an optical integrator (a fly-eye lens, an internal reflection type integrator, a diffractive optical element, etc.), a relay lens, a variable ND filter, and a reticle blind. , And an illumination optical system including a dichroic mirror and the like (both not shown). In this illumination system 12, a slit-shaped illumination area IAR portion (see FIG. 2) defined by a reticle blind on a reticle R on which a circuit pattern or the like is drawn is illuminated with illumination light EL with a substantially uniform illuminance. Here, as the illumination light EL, KrF excimer laser light (wavelength 248n
m) and other far-ultraviolet light, ArF excimer laser light (wavelength 1
93 nm) or F ₂ laser light (wavelength 157 nm)
Such as vacuum ultraviolet light is used. As the illumination light EL, it is also possible to use a bright line (g-line, i-line, etc.) in the ultraviolet region from an ultra-high pressure mercury lamp.

The reticle stage RST is arranged on the reticle base board 13 and has a predetermined scanning direction (here, the Y-axis direction which is the direction orthogonal to the paper surface of FIG. 1).
And a reticle scanning stage 14 that can be driven, and is mounted on the reticle scanning stage 14 and rotates in the X-axis direction (the left-right direction in the plane of FIG. 1), the Y-axis direction, and the rotation direction around the Z-axis orthogonal to the XY plane. A reticle fine movement stage 15 as a first movable body that can be finely driven in the (θz direction) is provided. The reticle R is held on the reticle fine movement stage 15 by vacuum suction or the like. The position of the reticle fine movement stage 15 in the XY plane is measured by a reticle interferometer 16 as a first position measuring device fixed on the reticle base plate 13 via a moving mirror 21.

More specifically, the reticle scanning stage 14 is moved in a predetermined stroke (stroke enough to allow the entire surface of the reticle R to cross at least the illumination light EL) on the reticle base plate 13 by a linear motor (not shown). It is designed to be driven in the axial direction.

As shown in FIG. 2, voice coil motors 22 and 24 are provided on both sides of the reticle fine movement stage 15 in the X-axis direction, respectively. The voice coil motor 22 includes a mover 18A fixed to the + X side of the reticle fine movement stage 15 and a stator 18B fixed to the upper surface of the reticle scanning stage 14 so as to face the mover 18A. The voice coil motor 24 includes a mover 19A fixed to the −X side of the reticle fine movement stage 15 and a stator 19B fixed to the upper surface of the reticle scanning stage 14 so as to face the mover 19A.

Voice coil motors 27 and 28 are provided on both sides of the reticle fine movement stage 15 in the Y-axis direction. The voice coil motor 27 is a mover 25A fixed to the + Y side of the reticle fine movement stage 15.
And a stator 25B fixed to the upper surface of the reticle scanning stage 14 so as to face it. The voice coil motor 28 includes a mover 26A fixed to the −Y side of the reticle fine movement stage 15 and a stator 26B fixed to the upper surface of the reticle scanning stage 14 so as to face the mover 26A.

In this case, the voice coil motors 22 and 24
Reticle fine movement stage 15 is driven in the Y-axis direction with respect to reticle scanning stage 14, and reticle fine movement stage 15 is driven by voice coil motors 27 and 28.
Are driven in the X-axis direction with respect to the reticle scanning stage 14. Also, for example, the voice coil motors 22 and 24
It is possible to control the amount of rotation of the reticle fine movement stage 15 in the θz direction by varying the driving force generated by.

As shown in FIG. 2, at the end of the upper surface of the reticle fine movement stage 15 on one side (-X side) in the X-axis direction, an X-shaped plane mirror having a reflecting surface perpendicular to the X-axis is formed.
The movable mirror 21x for the axis is extended in the Y-axis direction, and the movable mirror 2x
The laser beam LRx is emitted from the reticle X-axis interferometer 16x parallel to the X-axis at 1x. The reticle X-axis interferometer 16x interferes the return light from the reflecting surface of the movable mirror 21x with the return light from the reference unit (not shown), and based on the photoelectric conversion signal of the interference light, the reticle fine movement stage 1
The coordinate value of X in the X-axis direction is constantly detected with a resolution of, for example, about 0.5 to 1 nm.

Further, in the Y-axis direction of the reticle fine movement stage 15.
As shown in FIG. 2, on the side surface on one side (+ Y side),
For a pair of Y-axes consisting of a corner cube type reflective member
Moving mirror 21y₁, 21y₂Is fixed, these moving mirrors 2
1y₁, 21y₂The reticle Y-axis interferometer (not shown)
Laser beam LRy parallel to Y axis₁, LRy₂But
It is irradiated. Moving mirror 21y₁, 21y₂Reflected in
Laser beam LRy ₁, LRy₂Each is a reflective mirror
Reticle Y-axis interferometer (not shown) reflected by 38 and 39
The reticle Y-axis interferometer and the reticle X-axis interferometer.
Similar to 16x, each laser beam LRy
₁, LRy₂The coordinate position in the Y-axis direction at the irradiation position of
On the other hand, for example, always detect with a resolution of about 0.5 to 1 nm.
ing. Here, the reticle Y-axis interferometer has a double-pass interference.
And is affected by the rotation of the reticle fine movement stage 15.
Therefore, there is no measurement error. In addition,
The X-axis interferometer 16x should also be a double-pass interferometer.
You can

The measurement values of the reticle X-axis interferometer 16x and the reticle Y-axis interferometer are supplied to the main controller 20 of FIG. Main controller 20 controls the reticle fine movement stage based on the average value (y ₁ + y ₂ ) / 2 of coordinate values y ₁ and y ₂ measured by a pair of Y-axis interferometers using laser beams LRy ₁ and LRy _2. The Y coordinate value of 15 is calculated, and the X coordinate value of the reticle fine movement stage 15 is detected based on the coordinate value x measured by the reticle X axis interferometer 16x using the laser beam LRx. Further, main controller 20 uses, for example, the reticle fine movement stage 15 based on the difference between coordinate values y ₁ and y _2.
The rotation amount in the rotation direction (θz direction) is calculated. Main controller 20 controls reticle fine movement stage 15 as described above.
The position (including the θz rotation) in the XY plane is monitored.

As described above, the reticle fine movement stage 15
Above the movable mirror 21x for the X-axis and the movable mirror 21y for the Y-axis.
₁ , 21y ₂ are provided, and a plurality of laser interferometers are provided corresponding to these three, which are representatively shown as a moving mirror 21 and a reticle interferometer 16 in FIG. 1, respectively. The end faces of the reticle fine movement stage 15 may be mirror-finished to form the reflecting surfaces for the laser interferometer (corresponding to the reflecting surfaces of the movable mirrors 21x, 21y ₁ and 21y ₂ described above).

The projection optical system PL is arranged below the reticle stage RST in FIG. 1 and has its optical axis AX.
The direction (matching the optical axis of the illumination optical system) is the Z-axis direction. As the projection optical system PL, for example, a birefringent telecentric refracting optical system including a plurality of lens elements (not shown) arranged at predetermined intervals along the optical axis AX is used. The projection magnification of the projection optical system PL is, for example, 1/5 (or 1/4).

Therefore, when the illumination light EL from the illumination system 12 illuminates the illumination area IAR on the reticle R, the illumination light EL that has passed through the reticle R causes the illumination area IAR to pass through the projection optical system PL. A reduced image (partial inverted image) of the circuit pattern of the partial reticle R is formed on the wafer W whose surface is coated with a resist (photosensitive agent).

Further, among the plurality of lens elements forming the projection optical system PL, the plurality of lens elements on the object plane side (reticle R side) are arranged in the Z-axis by a drive element (not shown) such as a piezo element. Direction (projection optical system PL
Is a movable lens that can be driven to shift in the optical axis direction) and to be tilted with respect to the XY plane (that is, a rotation direction around the X axis and a rotation direction around the Y axis). Then, the imaging characteristic correction controller 49 independently adjusts the applied voltage to each drive element based on an instruction from the main control device 20, whereby each movable lens is individually driven,
Various imaging characteristics of the projection optical system PL (magnification, distortion, astigmatism, coma, field curvature, etc.) are adjusted. The image formation characteristic correction controller 49 can shift the center wavelength of the illumination light EL by controlling the light source, and can adjust the image formation characteristic by shifting the center wavelength similarly to the movement of the movable lens. .

The wafer stage WST is a wafer base board 1 arranged below the projection optical system PL in FIG.
It is placed on 7. Wafer stage WST is arranged on wafer base board 17 and is movable in the Y-axis direction.
A stage 23, an X stage 31 disposed on the Y stage 23 and capable of being driven in the X axis direction, and the X stage 31.
The Z-leveling stage 32 is mounted on the Z-leveling stage 32 as a second movable body that can be driven in the Z-axis direction and in the inclination direction with respect to the XY plane. The wafer W is held on the Z / leveling stage 32 by vacuum suction or the like via a wafer holder (not shown).

On the upper surface of the Z / leveling stage 32,
The position of the Z / leveling stage 32 is monitored by a wafer interferometer 48 as a second position measuring device which is fixed outside with the movable mirror 34, and the position information obtained by the wafer interferometer 48 is also the main controller. 20 are being supplied.

More specifically, as shown in the plan view of FIG. 3, a reflecting surface perpendicular to the X-axis is provided at one end (-X side end) of the upper surface of the Z / leveling stage 32 in the X-axis direction. A movable mirror 34X for the X-axis, which is composed of a plane mirror, is provided extending in the Y-axis direction, and one end (+ Y side end) in the Y-axis direction is composed of a plane mirror having a reflecting surface perpendicular to the Y-axis. Of the moving mirror 34Y is extended in the X-axis direction.

The movable mirror 34X does not receive the laser beams LWX and LW _of parallel to each other along the optical axis AX of the projection optical system PL and the optical path passing through the detection center of the alignment system ALG which will be described later. Two wafers X shown
Irradiation from each axis interferometer. On the movable mirror 34Y, two laser beams LWY1 and LWY2 having an interval IL along an optical path parallel to the Y-axis are arranged on a pair of wafers Y (not shown).
Irradiation from each axis interferometer.

The wafer X-axis interferometer and the wafer Y-axis interferometer are the same as the reticle X-axis interferometer 16x described above.
Each laser beam LWX, LW _of , LWY1,
Z / leveling stage 3 at the irradiation position of LWY2
The X coordinate value or the Y coordinate value of 2 is measured. Measurement values of these wafer X-axis interferometer and wafer Y-axis interferometer are supplied to main controller 20. At the time of exposure, which will be described later, main controller 20 uses coordinate values measured by an interferometer that uses laser beam LWX as the X coordinate of Z leveling stage 32, and laser beam LWY1 as the Y coordinate.
And the average value (Y ₁ + Y ₂ ) / 2 of the coordinate values Y ₁ and Y ₂ measured by the interferometer using LWY2, respectively. Further, main controller 20 calculates the rotation amount in the rotation direction (θz direction) of Z / leveling stage 32 from the difference between coordinate values Y ₁ and Y ₂ , for example. Particularly, in the Y-axis direction, which is the scanning direction, the average value of the measurement results of the pair of interferometers is used to prevent the accuracy deterioration due to the inclination of the Z / leveling stage 32 during scanning.

As described above, the Z / leveling stage 3
2 includes a moving mirror 34X for the X axis and a moving mirror 34Y for the Y axis.
Are provided, and a plurality of laser interferometers are provided in correspondence therewith, but in FIG. 1, these are representatively shown as a moving mirror 34 and a wafer interferometer 48, respectively.

At the time of exposure, the main controller 20 monitors the position of the Z / leveling stage 32 in the XY plane as described above, and the X / Y position of the Z / leveling stage 32 is monitored via the wafer drive unit 50. To control. In parallel with this, main controller 20 causes reticle scanning via a linear motor (not shown) based on the monitoring result of the Y position of Z / leveling stage 32 and the monitoring result of the Y position of reticle fine movement stage 15. The speed of the stage 14 is controlled, and the voice coil motors 22 and 24 are controlled.
The Y position of the reticle fine movement stage 15 is controlled via. Main controller 20 controls the X position of reticle fine movement stage 15 via voice coil motors 27 and 28 based on the result of monitoring the X position of reticle fine movement stage 15. Further, in main controller 20, based on the rotation amount of Z / leveling stage 32 in the θz direction and the rotation amount of reticle fine movement stage 15 in the θz direction, θz of reticle fine movement stage 15 is passed through voice coil motors 22 and 24. Controls the amount of rotation in the direction.

Further, when performing wafer alignment using an alignment system ALG which will be described later, main controller 20 performs Z / Y of leveling stage 32 in the same manner as described above.
While monitoring the position, the X position of the Z / leveling stage 32 is monitored based on the measurement value of a dedicated interferometer that uses the laser beam LW _of . This prevents a so-called Abbe error from occurring.

The wafer X-axis interferometer and the wafer Y-axis interferometer are multi-axis interferometers each having a plurality of length measuring axes, and the Z / leveling stage 32 is based on the measurement values of the respective length measuring axes.
Θy rotation (rolling), which is the direction of rotation around the Y axis of
It is also possible to measure θx rotation (pitching), which is the rotation direction around the X axis. In such a case, the Abbe error caused by the tilt of the Z / leveling stage 32 can also be corrected, so that the Z / leveling stage 32
Each of the end faces of the mirrors may be mirror-finished to form a reflection surface for the laser interferometer (corresponding to the reflection surfaces of the movable mirrors 34X and 34Y described above).

In the present embodiment, the wafer stage WST is not only moved in the scanning direction (Y-axis direction), but also a plurality of shot areas on the wafer W are irradiated with illumination light EL that is conjugate with the illumination area IAR (exposure area). ) It is configured to be movable in the non-scanning direction (X-axis direction) so that it can be positioned in the IA (see FIG. 3), and each shot area on the wafer W is scanned (scanned) as described later. ) A step-and-scan operation is repeated in which the operation of exposing and the operation of moving to the acceleration start position for exposure of the next shot are repeated.

On the wafer stage WST, as shown in FIG. 1, a fiducial mark plate FM is fixed so that its surface is substantially flush with the surface of the wafer W.
This fiducial mark plate FM is used to establish correspondence between the wafer stage coordinate system defined by the coordinates measured by the wafer interferometer 48 and the reticle stage coordinate system defined by the coordinates measured by the reticle interferometer 16. To be On the surface of the fiducial mark plate FM, for example, the relative positional relationship between the position of the detection center of the first fiducial mark for reticle alignment, which will be described later, and the alignment system ALG, which will be described later, and the position of the projected image of the reticle pattern is measured. Second reference marks and other reference marks for baseline measurement are formed. Among these reference marks, there is a reference mark illuminated from the back side by the illumination light guided to the Z / leveling stage 32 side, that is, a luminescent reference mark. The reference mark on the reference mark plate FM will be described later.

Further, in the exposure apparatus 100 of the present embodiment, as shown in FIG. 1, the wafer W is placed on the side surface of the projection optical system PL, more specifically, on the −Y side surface of the projection optical system PL. An off-axis type alignment system ALG for detecting the position of the alignment mark (wafer mark) attached to each shot area is provided. As this alignment system ALG, for example, Japanese Patent Laid-Open No. 2-5
Field Image Al as disclosed in Japanese Patent No. 4103
An ignition (FIA) type alignment sensor is used. The alignment system ALG irradiates the wafer W (or the reference mark plate FM) with illumination light (for example, white light) having a predetermined wavelength width, and the wafer mark on the wafer W (or the reference mark on the reference mark plate FM). Image and an image of an index mark on an index plate (not shown) arranged in a plane conjugate with the wafer are detected by forming an image on a light receiving surface of an image pickup device (CCD camera or the like) by an objective lens or the like. To do. The alignment system ALG is a wafer mark (or reference mark plate FM).
The imaging result of the upper reference mark) is output to the main controller 20.

Further, in this exposure apparatus 100, as disclosed in, for example, Japanese Patent Laid-Open No. 6-283403,
An irradiation optical system (not shown) that supplies an image forming light beam for forming a plurality of slit images toward the best image forming plane of the projection optical system PL from an oblique direction with respect to the optical axis AX, and the image forming light beam. An oblique-incidence multipoint focal point position detection system including an unillustrated light receiving optical system that receives each reflected light beam on the surface of the wafer W through a slit serves as an unillustrated holding member that supports the projection optical system PL. It is fixed. The multi-point focus position detection system detects position deviations in the Z-axis direction with respect to the image planes of a plurality of points on the wafer surface, and sets the Z / leveling stage 32 so that the wafer W and the projection optical system PL maintain a predetermined distance. It is used to drive in the Z-axis direction and the tilt direction. Wafer position information from the multipoint focal position detection system is sent to main controller 20, and main controller 20 moves Z / leveling stage 32 in the Z-axis direction via wafer drive unit 50 based on this wafer position information. And drive in the tilt direction.

Further, in the exposure apparatus 100, as shown in FIG. 1, a pair of mark detection systems for simultaneously observing the reference mark on the reference mark plate FM and the mark on the reticle R above the reticle R. Reticle alignment microscope (hereinafter abbreviated as “RA microscope”) 52
A and 52B are provided. In this embodiment, the deflection mirrors 43A and 43B for guiding the detection light from the reticle R to the RA microscopes 52A and 52B are movably arranged, and when the exposure sequence is started, the main controller 2
Under the command from 0, the mirror drive devices 54A, 54B
And the deflection mirrors 43A and 43B are integrated with each other by R
The A microscopes 52A and 52B are retracted from the optical path of the illumination light EL. The configurations of the RA microscopes 52A and 52B will be described later.

FIG. 4A is a plan view of the reticle R viewed from the pattern surface side (lower surface side in FIG. 1).
(B) shows the slit-shaped illumination area IAR in the area 33R on the reticle R that is conjugate with the effective exposure field of the projection optical system PL. Here, the scanning direction is the y-axis direction (the scanning axis direction in the reticle stage coordinate system that is substantially the same direction as the Y-axis direction in the wafer stage coordinate system. In this embodiment, a refraction system is used as the projection optical system PL. Therefore, the reticle stage and the wafer stage are scanned in the opposite directions, so that the y-axis and the Y-axis are opposite directions, and the two do not always coincide with each other, so that they are not identified here. Therefore, the direction is defined as the y-axis direction), and the direction orthogonal to the y-axis direction is defined as the x-axis direction.

In FIG. 4A, a light-shielding band ES is formed around the central pattern region PA on the reticle R, and marks (first mark) are formed on both outer sides of the light-shielding band ES in the x-axis direction.
Alignment marks (reticle marks) 29 _{1 to} 29 _n as marks and reticle marks 30 ₁ to 30 _n as second marks are formed. These reticle marks 29 _{1 to} 29 _n and 30 ₁ to 30 _n correspond to the pattern area P.
They are arranged at predetermined intervals along the y-axis that is the same distance from the center of A (reticle center) in the x-axis direction. The reticle marks 29 _i (i = 1 to n) and 30 _i are
They are arranged at the same y position. Cross marks, for example, are used as the reticle marks 29 _i and 30 _i . Although many reticle marks 29 _i and 30 _i are actually provided, FIG. 4A and the like show a case where n = 5 for convenience of drawing.

In FIG. 4B and FIG. 2 described above, reference numerals 52AR and 52BR respectively indicate observation areas of the RA microscopes 52A and 52B on the reticle R. Also,
In FIG. 3 described above, reference numerals 52AW and 52BW indicate observation regions corresponding to the observation regions 52AR and 52BR, respectively.

FIG. 5 (A) shows the reticle R of FIG. 4 (A).
A reticle image RW obtained when the image is projected onto the reference mark plate FM is shown. However, in FIG. 5 (A), the image of the light-shielding band ES and the pattern area PA portion therein is
For convenience of illustration, the illustration is omitted. In this FIG. 5 (A), the mark image 29W ₁ ~29W _n conjugate to the reticle mark 29 ₁ ~ 29 _n in FIG. 4 (A), the reticle mark 30 ₁ -
It is depicted conjugate with the mark image 30W ₁ ~30W _n to 30 _n.

FIG. 5B shows the arrangement of the reference marks on the reference mark plate FM. On the reference mark plate FM of FIG. 5 (B), the mark images 29W ₁ -29 of FIG.
29W _n and 30W ₁ ~30W _n substantially identical respectively disposed reference mark 35 ₁ to 35 _n and 36 ₁ ~ 36 _n are formed.

The reference marks 35 _i and 36 _i are as shown in FIG.
A mark having a shape as shown in an enlarged manner in (C) is used.

A reference mark 37 ₁ is formed on the reference mark plate FM at a position separated from the midpoint of the reference marks 35 ₁ and 36 _{1 by} a distance IL in the Y-axis direction which is the scanning direction. The interval IL is equal to the baseline amount (design value) which is the interval between the optical axis AX of the projection optical system PL and the detection center of the alignment system ALG in FIG. Similarly, the midpoints of the reference marks 35 ₂ and 36 ₂ and the reference marks 35 ₃ and 36 ₃
Midpoint of, ..., and a position away in the Y-axis direction by a spacing IL each from the midpoint of the reference mark 35 _n and 36 _n, the reference mark _{37 2, 37 3, ......,} 37 n are formed .

Although a large number of reference marks 35 _i and 36 _i are actually provided, FIG. 5B shows the case where n = 5 for convenience of drawing.

FIG. 6 shows the RA microscope 52A (52B) and the RA microscope 52A (52B).
And an example of the configuration of the illumination system. In this Figure 6
The optical fiber from outside the Z / leveling stage 32.
The illumination light EL having the same wavelength as the exposure light passes through
It is guided inside the leveling stage 32. Optical fiber
Relay the illumination light EL with a lens system instead of Iva 44
Is also good. The illumination light EL guided in this way is the lens
45A, beam splitter 45B and lens 45C
Reference mark 35 on the reference mark plate FM_iLighting the
The illumination light transmitted through the beam splitter 45B is reflected by the lens 45.
D, lens 45E, mirror 45F and lens 45G
Reference mark 36 on the reference mark plate FM _iIlluminating
It

For example, during reticle alignment,
As shown in FIG. 6, the light transmitted through the reference mark 35 _i is through the projection optical system PL, to form an image of the reference mark 35 _i on the reticle mark 29 _i on the reticle R.
The image of the reference mark 35 _i and the light from the reticle mark 29 _i are deflected by the deflection mirror 43A, the lens 40A, and the lens 40.
After passing through B, the light reaches the half mirror 42, and the light split into two by the half mirror 42 is incident on the image pickup surfaces of the image pickup element 56X for the x-axis and the image pickup element 56Y for the y-axis, which are each formed of a two-dimensional CCD.

In FIG. 7A, an image is formed on the screen of the image sensor.
Fiducial mark 35_iStatue of 35R_iIs shown in FIG.
(B) is a reticle imaged on the screen of the image sensor.
Ark 29 _iStatue of 29R_iIt is shown.

During actual reticle alignment, for example, the image pickup screen 56Xa of the image pickup element 56X for the x-axis is displayed.
As shown in FIG. 8A, the reticle mark 29
_i image 35R _i image 29R _i and the reference mark 35 _i of is projected superimposed. In this case, the direction of the horizontal scanning line of the image pickup screen 56Xa of the image pickup element 56X for the x axis is the x axis direction.

Therefore, the image pickup signal of the image pickup device 56X (S4
Image 35R _{i of the} fiducial mark 35 _i from the averaging
Positional displacement amount in the x-axis direction between the image 29R _i of the reticle mark 29 _i is calculated as. The image pickup signal S4X is supplied to the signal processing device 41 of FIG.

The image pickup signal S4X is detected as a digital signal by analog / digital conversion in the signal processing device 41. The image data on each scanning line is arithmetically averaged on the x-axis in the signal processing device 41, and the arithmetically averaged x-axis image signal S4X is as shown in FIG. 8B. Each of these image data is processed as a one-dimensional image processing signal. Although the horizontal axis of the image signal S4X is time t in FIG. 8B, the horizontal axis can be regarded as the position x by measuring the width of the image pickup screen 56Xa of the image pickup element 56X in advance. it can.

The signal thus obtained is used as a signal processing device.
The reticle mark shown in FIG.
29_iStatue of 29R_iPosition x in the x-axis direction corresponding to₃ , Criteria
Mark 35_iStatue of 35R_iThe position corresponding to the pattern on the left side of
Setting x₁ And its image 35R_iCorresponding to the pattern on the right side of
Position x₂ Is required. And the reticle mark 29 _i
Statue of 29R_iAnd fiducial mark 35_iStatue of 35R_iX-axis with
The relative positional deviation amount Δx in the direction is as follows.

Δx = x ₃ − (x ₁ + x ₂ ) / 2 (1) In this way, the amount of positional deviation in the x-axis direction between the reticle mark image and the reference mark image can be obtained.

On the other hand, the horizontal scanning line of the image pickup screen 56Ya (see FIG. 8A) of the y-axis image pickup element 56Y is the y-axis direction. Therefore, the positional shift amount Δy in the y-axis direction between the reticle mark image and the reference mark image can be obtained in exactly the same manner as the positional shift amount in the x-axis direction.

[0076] Similarly, by using the RA microscope 52B, the reticle mark 30 _i image 30R _i and the reference mark 36 _i image 3 of the
It is possible to obtain the amount of positional deviation in the x-axis direction and the y-axis direction from 6R _i .

The information of the positional deviation amount obtained as described above is sent from the signal processing device 41 to the main control device 20.

Next, in the exposure apparatus 100 of the present embodiment, the reticle R that changes according to the position in the scanning direction of the reticle fine movement stage 15 that is performed prior to the exposure sequence.
An example of a method of measuring the position information of is described. Here, a case where a so-called alignment error is measured as the position information of the reticle R will be described. As a premise,
Each reticle mark 29 _{1 to} 29 _n , 30 ₁ on the reticle R
The drawing error (positional error with respect to the design value) of up to 30 _n is measured in advance by using an external pattern measuring device such as a scanning electron microscope (SEM), and the measurement result is stored in the storage device 90 of FIG. Stored in. That is, the drawing error of each reticle mark is known.

Here, since reticle alignment, that is, the measurement of the relationship between the reticle stage coordinate system and the wafer stage coordinate system is not performed, the scanning direction of reticle stage RST is the y-axis direction and the y-axis direction as described above. The orthogonal direction is the x-axis direction.

First, the main controller 20 determines the reference mark plate F.
The pair of reference marks, for example, 35 ₁ and 36 ₁ of the emission marks 35 _i and 36 _i on M are placed at the observation position (see FIG. 1) at a position where the pair of RA microscopes 52A and 52B can observe them simultaneously. Wafer drive unit 50 for stage WST
To move through. After that, the wafer stage WST is servo-controlled so as to stand still at that position until the measurement is completed.

In this state, main controller 20 determines the reticle stage RS based on the measurement value of reticle interferometer 16.
While T is stepwise moved in the y-axis direction at predetermined intervals, the reticle mark pairs 29 ₁ , 30 ₁ , 29 ₂ , 3 on the reticle R are moved.
0 ₂ , ..., 29 _n , 30 _n and fiducial marks 35 ₁ , 36 ₁
And are sequentially observed using the RA microscopes 52A and 52B as described above. Here, during the above step movement, the measurement value of the interferometer 16x is maintained at a constant value,
The position of the reticle fine movement stage 15 is controlled in the x-axis direction via the voice coil motors 27 and 28. Then, the imaging information of the RA microscopes 52A and 52B is sent to the above-described signal processing device 41 for each observation position, and the signal processing device 41 causes the reticle mark 29 _i with respect to the reference mark 35 _{1 in} the x-axis direction and the y-axis direction. Displacement amount Δx _1i , Δy
_1i and the reticle mark 30 _i for the reference mark 36 _1.
The positional deviation amounts Δx _2i and Δy _{2i in} the x-axis direction and the y-axis direction are sequentially calculated. Then, the calculation result of the positional deviation amount is sequentially sent to the main control device 20. In the main controller 20, those positional deviation amounts are stored in the storage device 90 and stored in the reticle interferometer 1.
Sequentially stored with the output value of 6.

In this way, the deviation amounts of all the reticle mark positions on the reticle R with respect to the specific pair of reference marks 35 ₁ and 36 ₁ on the wafer stage WST are detected and stored in the storage device 90. It

Next, in main controller 20, x shift amount, x direction magnification error, y shift amount, and θz rotation amount at the y axis direction position of reticle fine movement stage 15 at which each reticle mark is observed, It is calculated as follows.

That is, main controller 20 uses the following equation (2).
The x shift amount Ox _i is calculated based on

Ox _i = (Δx _1i + Δx _2i ) / 2 (2) Further, main controller 20 obtains y shift amount Oy _i based on the following equation (3).

Oy _i = (Δy _1i + Δy _2i ) / 2 (3) Further, main controller 20 calculates θz rotation error θz _i based on the following equation (4).

Θz _i = (Δy _1i −Δy _2i ) / D (4) Note that the θz rotation error θz _{i + 1} is expressed by the following equation (5).
Alternatively, it can be calculated based on the equation (6). Here, D is the distance between the pair of reticle marks.

Θz _{i + 1} = (Δx _1i −Δx _{1i + 1} ) / P (5) θz _{i + 1} = (Δx _2i −Δx _{2i + 1} ) / P (6) Here, P is , Y is the interval (pitch) between adjacent reticle marks in the y direction.

Further, main controller 20 calculates x-direction magnification error Mx based on the following equation (7).

[0090]

[Equation 1]

[0091] The main controller 20, as described above, the obtained x shift Ox _i, y shift Oy _i, the [theta] z rotation error [theta] z _i, the horizontal axis and y-position for example, FIG. 9 (A) ~ Figure 9
Plots are made on an orthogonal coordinate system as shown in (C). Next, main controller 20 performs a statistical calculation such as the least squares method using the error component at each alignment position to curve fit each plot point (calculates an approximate curve). Thereby, for example, FIG.
An error curve Ox = f as shown in FIG.
(Y), Oy = g (y) and θz = h (y) are obtained.

Next, the main controller 20 stores the error curves Ox = f (y), Oy = g (y) and θz = h (y) obtained as described above in the storage device 90 respectively. Memorize as.

In the actual exposure sequence, main controller 20 first performs reticle alignment and baseline measurement of alignment system ALG as follows.

That is, wafer stage WST and reticle stage RST (more precisely, reticle fine movement stage 15) are sequentially moved in synchronization in the respective scanning directions, and a plurality of specific pairs of reticle marks on reticle R are moved. , 29 ₁ , 30 ₁ , 29 ₂ , 30 ₂ , and 29, for example
_n , 30 _n and the reference marks 35 ₁ , 36 ₁ , 35 ₂ , 36 ₂ ,
And 35 _n and 36 _n are sequentially observed using the RA microscopes 52A and 52B as described above, and the positional error between the corresponding marks is measured. Then, based on this measurement result, main controller 20 grasps the positional relationship between the reticle stage coordinate system and the wafer stage coordinate system. This completes the reticle alignment. Thereafter, based on the result of this reticle alignment, it is possible to correct the relative position / orientation error between reticle stage RST and wafer stage WST so as to minimize the scan range of the reticle stage.

By the way, in the exposure apparatus of the present embodiment, the fiducial mark plate FM as shown in FIG. 5B is used, and the RA microscopes 52A and 52B are used to form the reticle marks 29 ₁ and 30 ₁ , respectively. When simultaneously observing the reference marks 35 ₁ and 36 ₁ , it is possible to observe the reference mark 37 ₁ at the same time by using the alignment system ALG. That is, the baseline measurement is possible at the same time as the reticle alignment.

In the above case, the reticle marks 29 ₁ , 3
Each time 0 ₁ , 29 ₂ , 30 ₂ and 29 _n , 30 _n are observed, the amount of positional deviation of the reference marks 37 ₁ , 37 ₂ , 37 _{n from} the index center is not shown based on the output of the alignment system ALG. It is calculated by the alignment control device. Therefore, in the main controller 20, for example, the reticle mark 2
Based on the positional error between the reference marks 35 ₁ and 36 ₁ corresponding to the reference marks 9 ₁ and 30 ₁ , the displacement amount of the reference mark 37 _{1 from} the index center, and the designed baseline amount, the provisional baseline amount BS Calculate ₁ . Similarly, the main controller 20 sequentially calculates the temporary baseline amounts BS ₂ and BS _n each time the reticle mark is observed. Then, in the main controller 20, the temporary baseline amounts BS ₁ , BS ₂ , and BS
The average value of _n is the final baseline amount. Of course, any one of the temporary baseline amounts may be the final baseline amount, or the average value of any two of the temporary baseline amounts may be the final baseline amount.

When the reticle alignment and the baseline measurement are completed in this manner, for example, Japanese Patent Laid-Open No. 61-61
No. 44429 discloses EGA (Enhanced Global Alignment) type wafer alignment and performs six wafer parameters (X-axis direction scaling γx and Y-axis direction scaling γy, X-axis direction offset, Y-axis direction offset). , Orthogonality error and wafer rotation), and array coordinates of each shot area on the wafer W are calculated using these wafer parameters and a predetermined model formula.

Next, the wafer W is exposed to light.
Prior to this exposure, main controller 20 determines the true X-axis direction magnification error based on the X-axis direction scaling γx obtained in the process of wafer alignment of the EGA method and the x-direction magnification error Mx described above. Is calculated, and a command is given to the imaging characteristic correction controller 49 based on the calculation result. As a result, the imaging characteristic correction controller 49 adjusts the magnification of the projection optical system PL. As a result of this magnification adjustment, the wafer-induced magnification error and the reticle-induced magnification error are both corrected.

Based on the result of the wafer alignment, the operation of moving each shot area on the wafer W to the acceleration start position for the exposure and the reticle R and the wafer W are synchronized with each other in the scanning direction. The step-and-scan exposure is performed by repeating the scanning exposure operation of transferring the pattern of the reticle R to each shot area on the wafer W while moving along.

In the above scanning exposure, the pattern on the reticle R in the slit-shaped illumination area is illuminated by the exposure light EL from the illumination system 12, and the inverted image of the pattern is transmitted through the projection optical system PL. It is transferred onto the wafer W. At this time, in synchronization with the scanning of the reticle R with respect to the slit-shaped illumination area of the exposure light EL at a constant speed V on the front side of the paper surface of FIG. 1, the wafer W is on the back side of the paper surface of FIG. Are scanned at a substantially constant speed V / β (1 / β is the reduction magnification of the projection optical system PL).

During this scanning exposure, main controller 20 controls the X position of reticle fine movement stage 15 during scanning based on correction function Ox = f (y). As a result, the pattern transfer error due to the x-axis (X-axis) direction positional error of the reticle R including the positional error due to the bending of the movable mirror 21x is corrected.

During the above scanning exposure, the main controller 2
0 is the Y-axis direction scaling γy obtained in the above-described EGA type wafer alignment process, and the correction function Oy.
= G (y), the scanning speed of the reticle coarse movement stage 14 and the Y position of the reticle fine movement stage 15 are controlled to determine the speed ratio between the reticle R and the wafer W to the reticle fine movement stage 15 (reticle R). Y position (Y position)
Fine-tune each time. As a result, the pattern transfer error due to the Y-axis direction magnification error due to the wafer and the y-axis (Y-axis) direction magnification error due to the reticle is corrected.

Further, during the above scanning exposure, the main controller 2
0 controls the θz rotation amount according to the moving position of the reticle fine movement stage 15 in the scanning direction based on the correction function θz = h (y). As a result, the pattern transfer error due to the rotation error of the reticle fine movement stage 15 is corrected. It should be noted that the reticle fine movement stage 15 is rotated by a predetermined amount prior to the start of scanning based on the wafer rotation obtained in the above-described EGA type wafer alignment process, and based on this rotation angle, the reticle fine movement is performed. Rotational error correction is performed according to the moving position of the stage 15 in the scanning direction.

As is clear from the above description, in the present embodiment, the image formation characteristic correction controller 49 and the main control device 20 constitute a correction device. Further, the main control device 20 constitutes a measurement control device, a calculation device, and a stage control device.

As described in detail above, according to the exposure apparatus 100 of the present embodiment, the position information of the reticle, which cannot be measured by the laser interferometer and fluctuates according to the moving position of the reticle R in the predetermined direction (scanning direction), is obtained. It is possible to measure reliably.

Further, while the reticle R and the wafer W are synchronously moved in the scanning direction, the measurement result (for example, position information that varies depending on the moving position of the reticle R in the scanning direction (scanning direction component of position error, non-scanning). The reticle pattern is transferred by finely adjusting at least one of the position, speed, and orientation of the reticle R based on the measurement result of the directional component and the rotation of the reticle R). Therefore, according to the exposure apparatus 100 and the exposure method thereof of the present embodiment, the reticle R
It is possible to suppress the occurrence of distortion of the transferred image of the pattern on the wafer W due to a magnification error in the synchronous movement direction, a position error orthogonal to the synchronous movement direction, a rotation error, or the like according to the position in the synchronous movement direction. It will be possible.

In the above embodiment, as described above, the magnification error in the synchronous movement direction, which changes depending on the position of the reticle R in the synchronous movement direction, the position error orthogonal to the synchronous movement direction,
The case where all the rotation errors are measured in advance, and at least one of the position, the speed, and the posture of the reticle R is finely adjusted based on the measurement result to transfer the pattern has been described. It is not limited to.
That is, the above embodiment is only an example of the embodiment of the present invention, and any one or two of the scanning direction component of the position error of the reticle R, the non-scanning direction component, the rotation of the reticle R, or the like is used. May be measured in advance and the position, orientation, etc. of the reticle R may be corrected based on the measurement result.

Further, in the above embodiment, the position error, the magnification error, the rotation error and the like are corrected by using only the reticle fine movement stage 15, but the wafer stage W
Various errors may be corrected by using only ST or both reticle stage RST and wafer stage WST. At this time, using wafer stage WST as a coarse / fine movement stage, for example, by using a voice coil motor or an EI core, Z / leveling stage 32 can be moved in at least X and Y directions with respect to X stage 31, and θ
The Z-leveling stage 32 may be finely moved in 6 degrees of freedom.

The arrangement and mark configuration of the reticle marks on the reticle R in the above embodiment are merely examples.
Of course, the present invention is not limited to this. For example, in the above-described embodiment, the case where the reticle marks are arranged on the reticle R at equal intervals and in the left-right symmetry along the Y-axis direction (scanning direction) has been described, but the present invention is not limited to this, and the reticle marks are Only one row may be arranged on one side of the pattern area on the reticle R. Even in such a case, it is possible to measure the scanning direction component, the non-scanning direction component, and the rotation of the reticle R of the position error that varies depending on the position of the reticle R in the scanning direction. Further, the reticle marks do not have to be arranged side by side on a straight line, and a plurality of reticle marks (alignment marks) may be arranged at a plurality of different positions in the scanning direction at predetermined intervals. Even in such a case, the reference mark plate FM
By detecting the positional deviation amount of each reticle mark with respect to any one of the reference marks above, the scanning direction component of the position error that varies depending on the position of the reticle R in the scanning direction,
The non-scanning direction component, the rotation of the reticle R, and the like can be measured in the same manner as described above, and by controlling at least one of the position and the posture of the reticle R during scanning based on the measurement result, the reticle R can be placed on the wafer. It is possible to suppress the occurrence of distortion of the transferred image of the transferred reticle pattern.

Further, a pair of markers arranged on the reticle R is used.
Mark, eg Mark 29_iAnd 30_iAnd at the same y position
It does not have to be placed. That is, the reticle mark
Thirty _iBut the reticle mark 30_iTo the overall predetermined distance
The arrangement may be shifted in the y-axis direction by a distance.

Further, in the above embodiment, for simplification of description, the case where the reticle used for transferring the pattern and the measurement reticle used for measurement for calculating the error curve are the same reticle R has been described. However, the present invention is not limited to this, and both may be separate reticles. In such a case, the reticle used for transferring the pattern may have at least a pair of reticle marks necessary for reticle alignment. Alternatively, instead of the reticle R, a pattern forming member (reference mark plate of the reticle stage RST) is fixed to the reticle fine movement stage 15, and a plurality of alignment marks (reference marks) are attached to the pattern forming member, for example, the reticle R of the above embodiment. The error curve may be calculated by arranging in the same manner and using the alignment mark on the pattern forming member as a measurement target. That is, the mark existing on the first movable body of the present invention is the mark on the first object (reticle R in the above embodiment) placed on the first movable body (reticle fine movement stage 15 in the above embodiment). However, it may be a mark formed on the first movable body itself. Alternatively, a mark on an object different from the first object placed on the first movable body may be used.

When using a reference mark other than the alignment mark of the first object (reticle), for example,
It is desirable to obtain the positional relationship between the reference mark and the reticle pattern (that is, the alignment mark) using an RA microscope or the like.

In the above embodiment, the reticle stay is used.
Do not move the RST step in the y-axis direction at a predetermined interval.
, Reticle mark pair on reticle R 29₁, 30₁Two
9₂, 30₂, ……, 29_n, 30_nAnd fiducial mark 3
5₁, 36₁And, using RA microscopes 52A and 52B,
The next observation is made, but not limited to this, the reticle
Image RST so that there is no problem in capturing the image in the y-axis direction.
Reticle mark pair 2 while moving continuously at a speed of 2 degrees
9₁, 30₁, 29₂, 30₂, ……, 29_n, 30_nAnd the base
Associate mark 35₁, 36₁It may be good to observe and.
Reticle interferometer 16 while moving reticle stage RST
Each reticle mark pair 29 based on the measured value of _i, 30_iBut
By recognizing the position within the observation field of the RA microscope
Also, such a method can be easily realized.

In the above embodiment, the fiducial mark plate F
Although the reticle mark is detected by the RA microscope using M as a light emitting type, the RA microscope may be configured to detect the light reflected by the reference mark plate FM by epi-illuminating the reticle mark.

Further, in the above embodiment, the reticle mark 2 is defined with reference to the reference marks (35 ₁ , 36 ₁ ) formed on the reference mark plate FM on the wafer stage WST side.
The case of obtaining the positional deviation amounts of 9 _i and 30 _i has been described, but the present invention is not limited to this, and a reference mark is provided in the RA microscope and the reticle marks 29 _i and 29 _i are set with the mark as a reference.
The positional deviation amount of 30 _i may be obtained.

Further, in the above embodiment, the mark detection system (RA microscope) of the image pickup system is used to detect the mark on the reticle or the reticle stage, but the mark detection system is not limited to the image pickup system. , Any method is acceptable. For example, one coherent beam is applied to the reference mark plate FM almost vertically, and the reticle mark is irradiated with ± first-order diffracted light generated from the reference mark.
A method in which two diffracted lights generated from the reticle mark are made to interfere with each other and may be detected.

The application of the exposure apparatus is not limited to the exposure apparatus for manufacturing semiconductors, and for example, an exposure apparatus for liquid crystal for transferring a liquid crystal display element pattern onto a rectangular glass plate or a thin film magnetic head. Do, Micromachine and D
It can be widely applied to exposure apparatuses for manufacturing NA chips and the like. Moreover, not only microdevices such as semiconductor elements, but also light exposure apparatus, EUV exposure apparatus, X-ray exposure apparatus,
The present invention can also be applied to an exposure apparatus that transfers a circuit pattern onto a glass substrate, a silicon wafer, or the like in order to manufacture a reticle or mask used in an electron beam exposure apparatus or the like.

As the exposure illumination light used in the exposure apparatus, a single-wavelength laser light in the infrared region or visible region emitted from a DFB semiconductor laser or a fiber laser is used.
For example, it is possible to use a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal. Further, the magnification of the projection optical system is not limited to a reduction system, and may be a unity magnification system or a magnification system.

<< Device Manufacturing Method >> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus and exposure method in a lithography process will be described.

In FIG. 10, devices (semiconductor chips such as IC and LSI, liquid crystal panel, CCD, thin film magnetic head,
A flow chart of a manufacturing example of a micromachine etc. is shown. As shown in FIG. 10, first, step 20
In 1 (design step), a device function / performance design (for example, circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Then, in step 202 (mask making step),
A mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step),
A wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), the mask and wafer prepared in steps 201 to 203 are used to form an actual circuit or the like on the wafer by a lithography technique or the like, as described later. . Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. This step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as needed.

Finally, step 206 (inspection step)
In step 2, inspections such as an operation confirmation test and a durability test of the device manufactured in step 205 are performed. After these steps, the device is completed and shipped.

FIG. 11 shows a detailed flow example of step 204 in the case of a semiconductor device. In FIG. 11, step 211 (oxidation step)
In, the surface of the wafer is oxidized. Step 212
In the (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode forming step), electrodes are formed on the wafer by vapor deposition. Step two
In 14 (ion implantation step), ions are implanted in the wafer. Steps 211 to 214 above
Each of them constitutes a pretreatment process of each stage of wafer processing, and is selected and executed according to the required treatment in each stage.

At each stage of the wafer process, after the above-mentioned pretreatment process is completed, the posttreatment process is executed as follows. In this post-treatment process, first, step 2
In 15 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred onto the wafer by the above-described exposure apparatus and exposure method. next,
In step 217 (developing step), the exposed wafer is developed, and in step 218 (etching step), the exposed member other than the portion where the resist remains is removed by etching. Then, in step 219 (resist removing step), the unnecessary resist after etching is removed.

By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

When the device manufacturing method of this embodiment described above is used, since the above-described exposure apparatus 100 is used in the exposure step (step 216), it is possible to perform exposure with good pattern transfer accuracy. By improving the yield of the final product, the device, its productivity can be improved.

[0127]

As described above, according to the measuring method of the present invention, it is possible to reliably measure the position error of the object which fluctuates according to the moving position of the movable body on which the object is placed. There is.

Further, according to the exposure method and the exposure apparatus of the present invention, it is possible to reduce the distortion of the transferred image of the pattern.

According to the device manufacturing method of the present invention, there is an effect that the productivity of devices can be improved.

[Brief description of drawings]

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

FIG. 2 is a plan view showing the reticle stage of FIG.

3 is a plan view showing the Z / leveling stage of FIG. 1. FIG.

4A is a plan view of the reticle viewed from the pattern surface side, and FIG. 4B is a slit-like illumination in a region 33R on the reticle conjugate with an effective exposure field of the projection optical system. It is a figure which shows area | region IAR etc.

5A is a diagram showing a reticle image obtained when the reticle of FIG. 4A is projected onto a reference mark plate;
FIG. 5B is a diagram showing the arrangement of the reference marks on the reference mark FM, and FIG. 5C is an enlarged view showing the reference marks.

FIG. 6 is a diagram showing an example of the configurations of an RA microscope and its illumination system.

7A is a diagram showing an image of a reference mark formed on a screen of an image sensor, and FIG. 7B is an image of a reticle mark formed on a screen of an image sensor. FIG.

8A is a diagram showing a state in which an image of a reticle mark and an image of a reference mark are superimposed and projected on an image pickup screen of an x-axis image pickup device, and FIG. 8B is a diagram showing FIG. It is a figure which shows the imaging signal S4X corresponding to the imaging screen of (A).

9A-9C are x-axis direction shifts,
It is a figure for demonstrating the calculation method of a y-axis direction shift and the correction function of a rotation error, respectively.

FIG. 10 is a flowchart for explaining a device manufacturing method according to the present invention.

11 is a flowchart showing a specific example of step 204 of FIG.

[Explanation of symbols]

15 ... Reticle fine movement stage (first movable body), 16 ... Reticle interferometer (first position measuring device), 20 ... Main control device (measurement control device, arithmetic device, stage control device, part of correction device), 29 _i ... Reticle mark (first mark),
30 _i ... Reticle mark (second mark), 32 ... Z-leveling stage (second movable body), 48 ... Wafer interferometer (second position measuring device), 49 ... Imaging characteristic correction controller (part of correction device) ), 52A, 52B ... RA microscope (mark detection system), 100 ... Exposure device, R ... Reticle (first object), W ... Wafer (second object), PL ... Projection optical system.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA03 BB02 BB29 CC20 FF04                       FF51 GG03 GG04 JJ03 JJ05                       JJ26 LL00 LL02 LL04 LL20                       LL23 LL28 LL59 LL62 MM03                       MM04 PP12 QQ03 QQ18                 2F069 AA03 BB15 BB40 CC06 GG07                       HH09 HH30 JJ14 NN08                 5F046 BA04 BA05 CB12 CB17 CB25                       CC01 CC02 CC03 CC05 CC06                       DA05 DA13 DD06 EA02 EB02                       EB03 ED03 FA16 FC04 FC05

Claims (13)

[Claims] 1. A measuring method for measuring positional information of an object, which varies according to a moving position of a movable body on which the object is placed, the measuring method being arranged on the movable body at predetermined intervals in a first axis direction. A first step of sequentially measuring the position information of each of the plurality of first marks while moving the movable body along the first axis direction; and the first of the position information of each of the first marks.
A second step of calculating a component in the axial direction and determining a relationship between the component in the first axial direction of the position information and the position of the object in the first axial direction based on the calculation result; . 2. A component of the position information of each of the first marks in a second axis direction orthogonal to the first axis direction is calculated, and a component of the position information in the second axis direction is calculated based on the calculation result. The measuring method according to claim 1, further comprising a third step of obtaining a relationship between at least one of the rotation amount of the movable body and the position of the movable body in the first axial direction. 3. A plurality of second marks are further arranged on the movable body at the predetermined intervals in the first axis direction, and position information of each of the plurality of second marks is obtained in the first step. The first mark forming a set in which the position information is measured when the object is at the same position as when the position information of each of the first marks is measured, and the position information is measured when the object is at the same position; The difference between the second mark and the component of each position information in the first axis direction is calculated for each set, and the rotation amount of the movable body and the first axis of the movable body are calculated based on the calculation result. The measuring method according to claim 1, further comprising a third step of obtaining a relationship with a position in the direction. 4. A plurality of second marks are further arranged on the movable body at the predetermined intervals in the first axis direction, and position information of each of the plurality of second marks is obtained in the first step. The first mark forming a set in which the position information is measured when the object is at the same position as when the position information of each of the first marks is measured, and the position information is measured when the object is at the same position; The difference between the second mark and the component of the position information in the second axis direction orthogonal to the first axis is calculated for each set, and the second value of the object is calculated based on the average value of the calculated results. The measuring method according to claim 1, further comprising a third step of obtaining the amount of expansion and contraction in the axial direction. 5. An exposure method for transferring a pattern formed on a first object to a second object, comprising: the measuring method according to claim 1.
Measuring position information that varies according to the moving position of the movable body in the first axis direction using a plurality of marks on the movable body on which the first object is placed; the first object and the first object Two
While synchronously moving the object in the first axis direction, at least one of the relative position, speed, and attitude of the first object and the second object is finely adjusted based on the measurement result, and the pattern An exposure method including the step of: 6. An exposure method for transferring a pattern formed on a first object to a second object via a projection optical system, wherein the second object of the first object is measured by the measuring method according to claim 4. Measuring the amount of expansion and contraction in the axial direction; adjusting the magnification of the pattern image based on the measurement result; moving the first object and the second object synchronously in the first axial direction, And a step of transferring a pattern image of which magnification is adjusted to the second object. 7. An exposure apparatus which transfers a pattern existing on the first object onto the second object via a projection optical system by synchronously moving the first object and the second object in the first axis direction. A first movable body on which the first object is mounted; a second movable body on which the second object is mounted; a mark detection system for detecting a mark existing on the first movable body; A first position measuring device that measures the position of the first movable body; a second position measuring device that measures the position of the second movable body; and the first movable body based on the output of the first position measuring device. While moving the first mark along the first axis direction, using the mark detection system, position information of each of a plurality of first marks arranged on the first movable body at predetermined intervals in the first axis direction. A measurement control device for sequentially measuring the position information of each of the measured first marks; Based on the position of the first movable body in the first axial direction, the magnification resulting from the expansion / contraction amount of the first movable body in the first axial direction, and the position in the second axial direction orthogonal to the first axis. An arithmetic unit for calculating correction information for correcting at least one of a deviation amount and a rotation amount; and, at the time of transferring the pattern, based on the outputs of the first and second position measuring devices, the first movable body and the first movable body. And a stage control device that finely adjusts the moving state of the first movable body based on the calculation result of the calculation device, while simultaneously moving the two movable bodies in the first axis direction. 8. The correction information is information for correcting a magnification caused by an expansion / contraction amount of the first movable body in the first axial direction according to a position of the first movable body in the first axial direction. The stage control device finely adjusts the speed of the at least one of the first and second movable bodies during the synchronous movement according to the output of the first measuring device. Exposure equipment. 9. The correction information is information for correcting a positional displacement amount in a second axial direction according to a position of the first movable body in the first axial direction, and the stage control device is configured to control the first controller.
8. The exposure apparatus according to claim 7, wherein the position of at least one of the second movable body and the second movable body during the synchronous movement is finely adjusted in accordance with the output of the first measuring device. 10. The correction information is information for correcting a rotation amount of the first movable body according to a position of the first movable body in the first axial direction, and the stage control device is configured to perform the synchronous movement. 8. The exposure apparatus according to claim 7, wherein the relative rotation amount of the first and second movable bodies at the time is finely adjusted according to the output of the first measuring device. 11. A plurality of second marks are further arranged on the first movable body at the predetermined intervals in the first axis direction, a pair of the mark detection systems is provided, and the measurement control device includes the first mark. The position information of each of the plurality of first marks on one movable body is sequentially measured using the one mark detection system, and at the same time, the position information of each of the plurality of second marks is detected. The first mark of each of the position information of the first mark and the second mark that form a set in which the position information is measured when the first movable body is at the same position by sequentially measuring using the system. The difference between the components in the direction of the second axis orthogonal to the axis is calculated for each pair, and the first value is calculated based on the average value of the calculation results.
Further, a correction value of the magnification due to the expansion / contraction amount of the movable body in the second axis direction is further obtained, and prior to the transfer of the pattern, the correction of the magnification due to the expansion / contraction amount of the first movable body in the second axis direction is performed. The exposure apparatus according to claim 7, further comprising a correction device that corrects a magnification of the pattern image based on a value. 12. The position information is information on a position error with respect to a reference mark on the second movable body, and the mark detection system includes a mark existing on the first movable body and the reference mark. The exposure apparatus according to any one of claims 7 to 11, wherein the exposure apparatus is a system that performs detection through a projection optical system. 13. A device manufacturing method including a lithography process, wherein in the lithography process, exposure is performed using the exposure apparatus according to claim 7. .