JP2009295701A - Aligner and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner for suppressing the change of a wavefront aberration generated in the measurement system of a Fizeau interferometer and preventing the deterioration of measurement accuracy of the wavefront aberration of a projection optical system. <P>SOLUTION: The aligner comprises: the Fizeau interferometer comprising an objective lens front group loaded on an original stage and provided with a Fizeau surface for forming reference light, an objective lens rear group positioned more on the upstream side than the objective lens front group, and a reflection mirror loaded on a substrate stage for forming light to be detected; and a TTR type detection system provided with a third objective lens group positioned more on the upstream side than the mark of an original reference plate, for simultaneously observing the mark of the original reference plate configured on the original stage and the mark of a substrate reference plate configured on the substrate stage through a projection optical system and measuring the relative position of the original stage and the substrate stage. In the aligner for projecting and aligning the pattern of the original on a substrate through the projection optical system, the objective lens rear group and the third objective lens group are arranged at the same driving table configured separately from the original stage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a projection exposure apparatus for manufacturing a semiconductor, and more particularly to an exposure apparatus for manufacturing a semiconductor used in a lithography process for manufacturing a semiconductor element or a liquid crystal display element.

When a semiconductor device such as an IC or LSI, an imaging device such as a CCD, a display device such as a liquid crystal panel, or a device such as a magnetic head is manufactured in a photolithography process, the pattern formed on the mask (reticle) is transferred to the object to be exposed. A projection exposure apparatus is used.
In recent years, there has been an increasing demand for an exposure apparatus that exposes a large screen with high resolution with high accuracy and economical efficiency. In order to increase the resolution, the exposure light has a shorter wavelength and the numerical aperture (NA) of the projection optical system is increasing. In order to enlarge the exposure area, a so-called stepper and projection exposure apparatus (hereinafter referred to as “scanner”) that shifts the reticle and the wafer relative to each other with a slit shape from the so-called stepper are used. I am doing.
Since a projection exposure apparatus is required to accurately transfer a pattern on a reticle to an object to be exposed at a predetermined magnification, it is important to use a projection optical system with good imaging performance and reduced aberrations. . Particularly in recent years, due to the demand for further miniaturization of semiconductor devices, the transfer pattern has become sensitive to aberrations of the optical system. Therefore, there is a demand for measuring the optical performance (for example, wavefront aberration) of the projection optical system with high accuracy.
The optical performance of the projection optical system is measured not only when adjusting the spacing and decentration of a predetermined lens and lens group when assembling and adjusting the projection optical system alone, but also equipped with a projection optical system in the projection exposure apparatus. There is also a need to measure subsequent changes in optical performance of projection optics.
For this reason, it is known that a Fizeau interferometer is mounted on a projection exposure apparatus as means for measuring the optical performance of the projection optical system after being mounted on the projection exposure apparatus. (See Patent Document 1)

With reference to FIG. 8, the structure of the Fizeau interferometer mounted on the projection exposure apparatus will be described.
The KrF excimer laser 101 is a light source for exposure, and the light 101a emitted from the KrF excimer laser 101 is shaped by the beam shaping optical system 102 into a symmetric beam shape with respect to the optical axis. The light whose coherence distance is reduced by the incoherent unit 103 irradiates the reticle 115 through the illumination optical system 104. A circuit pattern is drawn on the reticle 115 and forms an image at the position 117 by the projection optical system 116. The chuck 118 mounts a wafer and is fixed to the substrate stage 119. The dedicated light source 106 is a light source of the interferometer. The laser beam passes through a condensing system 107 and a pinhole 108 via a mirror 106a, and forms a parallel beam by a collimator lens 109. The formed parallel beam enters the objective lens 112 via the half mirror 110 and the mirror 111. The mirror 111 and the objective lens 112 are held on the XYZ stage 105. In the Fizeau interferometer, the radius of curvature of the final surface (Fizeau surface) of the objective lens 112 of the Fizeau interferometer arranged on the object plane side of the projection optical system 116 is a position corresponding to the pattern surface 115 of the reticle. It is the same as the distance. Reflected light from the final surface (Fizeau surface) of the objective lens 112 is guided as reference light to the light receiving surface of the CCD 128 that is an image sensor through the condensing system 127 via the mirror 111 and the half mirror 110.
In the projection exposure apparatus, a movable substrate stage 119 is disposed on the image plane side of the projection optical system 116, and a movable substrate stage 119 is disposed. The substrate stage 119 has a part of the function of the Fizeau interferometer. The spherical mirror 120 which comprises is arrange | positioned. The radius of curvature of the spherical mirror 120 is made to coincide with the distance from the imaging position 117 of the projection optical system 116. Therefore, the light transmitted through the final surface (Fizeau surface) of the objective lens 112 of the Fizeau interferometer forms an image at the position corresponding to the reticle pattern, and then forms an image at the image plane position 117 on the wafer side by the projection optical system 116. After the image formation, the light reflected by the spherical mirror 120 disposed on the substrate stage 119 that holds the wafer is condensed again at the image formation position of the projection optical system 116 and returns to the projection optical system 116, and the objective lens 112, mirror 111, through the half mirror 110, through the condensing system 127, and guided to the light receiving surface of the CCD 128, which is an image sensor. Since the light (test light) reciprocated through the projection optical system 116 interferes with the reference light reflected by the final surface (Fizeau surface) of the objective lens 112, the wavefront measurement of the projection optical system 116 becomes possible.
JP 2005-333149 A

In order to measure the wavefront of the projection optical system with high accuracy, the final position of the objective lens (Fizeau surface) and the spherical mirror placed on the substrate stage must be synchronously controlled when generating the reference light and test light. There is. Therefore, the objective lens final surface (fizone surface) is configured as a reticle stage that is synchronously controlled with the substrate stage. Further, in order to obtain the wavefront error of the Fizeau interferometer itself that does not include the projection optical system, a reference spherical mirror is disposed between the projection optical systems, and the wavefront measurement of the reference spherical mirror is performed. After obtaining the wavefront aberration of the Fizeau interferometer itself, the Fizeau interference must be controlled if the optical axis shift between the Fizeau surface configured on the reticle stage and the optical system of the Fizeau interferometer is not suppressed to submicron accuracy. The wavefront aberration of the meter itself changes. The spherical mirror on the object plane side used when obtaining the wavefront aberration of the Fizeau interferometer itself is arranged in a region that does not block exposure light. For this reason, when measuring the wavefront aberration of the projection optical system, it is necessary to drive a reticle stage having a Fizeau surface and a part of the optical system of the Fizeau interferometer. If there is an error in driving part of the optical system of the Fizeau interferometer with respect to the driving of the original stage, the wavefront aberration of the Fizeau interferometer itself will change and the measurement accuracy of the wavefront aberration of the projection optical system will deteriorate. It becomes a factor to do.
SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus that suppresses changes in wavefront aberration that occur in a measurement system of a Fizeau interferometer and prevents deterioration in measurement accuracy of wavefront aberration of a projection optical system.

  An exposure apparatus according to the present invention for solving the above-described problems includes an original stage for holding an original, a substrate stage for holding a substrate, and an objective lens front group having a Fizeau surface mounted on the original stage to form reference light, An objective lens rear group located upstream from the objective lens front group and a Fizeau interferometer comprising a reflection mirror mounted on the substrate stage to form test light; and an original reference plate mark formed on the original stage; A mark on the substrate reference plate configured on the substrate stage is simultaneously observed through a projection optical system, a relative position between the original stage and the substrate stage is measured, and a third position located upstream from the mark on the original reference plate. An exposure apparatus for projecting and exposing the pattern of the original onto the substrate via the projection optical system. In the said objective lens rear group, the third group of the objective lens, characterized in that it is arranged on the same drive table constructed separately from the original stage.

  According to the present invention, a change in wavefront aberration that occurs in a measurement system of a Fizeau interferometer is suppressed, and deterioration in measurement accuracy of wavefront aberration in a projection optical system is prevented.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
With reference to the schematic block diagram of FIG. 1, the exposure apparatus of Example 1 of this invention is demonstrated.
In FIG. 1, an XYZ rectangular coordinate system is set, and the positional relationship of each component will be described with reference to this XYZ rectangular coordinate system. In the XYZ orthogonal coordinate system, the X direction and the Y direction are set to be parallel to the wafer 7, and the Z direction is set to a direction orthogonal to the wafer 7. In this embodiment, the XYZ orthogonal coordinates in FIG. In the system, the XY plane is set to a plane parallel to the horizontal plane, and the Z direction is set to the vertically upward direction.
The first embodiment is an exposure apparatus that projects and exposes a pattern of a reticle 6 as an original onto a wafer 7 as a substrate via a projection optical system PL. The first embodiment is applied to a scanning projection exposure apparatus having an exposure wavelength of 193 nm (ArF excimer laser). The exposure wavelength is not limited to 193 nm, i-line or KrF excimer laser (248 nm), and EUV as a light source. The present invention can also be applied to a projection exposure apparatus.
The exposure light source 1 is composed of an ArF excimer laser, and the light 1a emitted from the exposure light source 1 is shaped into a beam shape symmetric with respect to the optical axis by the beam shaping optical system 2. Further, the light whose coherence distance is reduced by the incoherent unit 3 irradiates the reticle 6 which is the original held on the reticle stage 5 which is the original stage through the exposure illumination system 4. A predetermined circuit pattern is drawn on the reticle 6 and forms an image on the wafer 7 by the projection optical system PL. A wafer 7 as a substrate is held and fixed to a wafer stage 8 as a substrate stage by a wafer chuck (not shown). The reticle stage 5 has the Y direction as the scanning direction during exposure, and can be driven in the rotational directions of the XYZ and XYZ axes. The wafer stage 8 can also be driven in the rotational directions of the XYZ and XYZ axes. In addition to the above, the projection exposure apparatus of the first embodiment is equipped with a wafer alignment detection system, a focus detection system, and the like, which are omitted here for the sake of simplicity.
Further, the main body control unit (not shown) uses a laser interferometer (not shown) arranged around each of the reticle stage 5 and the wafer stage 8 to change the optical axis direction of the projection optical system PL and the projection optical system PL. The position of each stage in a plane perpendicular to the optical axis is measured. Further, the main body control unit synchronously controls the reticle stage 5 and the wafer stage 8 in nm order.
Above the reticle stage 5, a TTR detection system 10 which is a TTR microscope and a Fizeau interferometer 20 for measuring the wavefront aberration of the projection optical system PL are configured in the same casing.

In order to perform the wavefront measurement of the projection optical system PL with high accuracy, it is necessary to suppress or correct the fluctuation in the interferometer system. In a Fizeau interferometer mounted on a scanning exposure apparatus, a Fizeau surface that generates reference light is formed on a reticle stage 5 that holds and scans a reticle 6. In addition, a spherical mirror that reflects light that has passed through the projection optical system PL and generates test light is configured on the wafer stage 8 that holds and operates the wafer, and the reticle stage 5 and the wafer stage 8 are synchronously controlled with high accuracy. By doing so, it is known to suppress fluctuations in the interferometer system.
In addition, in order to distinguish the wavefront aberration of the Fizeau interferometer itself from the wavefront aberration of the projection optical system PL, the wavefront of the Fizeau interferometer is measured in advance, and the amount of wavefront aberration of the interferometer is measured by the projection optical system PL. By subtracting and correcting from the result, the wavefront aberration of the projection optical system PL can be accurately obtained. In order to measure the wavefront aberration of the interferometer, a spherical mirror whose center of curvature is located in the object plane is arranged on the object plane side of the projection optical system PL. It is known to measure the wavefront aberration of the Fizeau interferometer itself by measuring the wavefront aberration by making the spherical mirror, the Fizeau surface constituting the reticle stage 5 substantially coincide with the optical axis of the Fizeau interferometer. ing.

Next, the TTR detection system 10 of the projection exposure apparatus according to the first embodiment of the present invention will be described with reference to the schematic block diagram of FIG.
The TTR detection system 10 includes a TTR microscope. The TTR detection system 10 includes a mark 50a on the reticle reference plate 50 that is a mark on the original reference plate formed on the reticle stage 5 and a mark on the wafer reference plate 80 that is a mark on the substrate reference plate formed on the wafer stage 8. 80a is simultaneously observed through the projection optical system PL. The TTR detection system 10 further includes an objective lens 16 that measures the relative position of the reticle stage 5 and the wafer stage 8 and is a third objective lens group located upstream of the mark on the original reference plate.
The light 1a from the exposure light source 1 is guided to the illumination unit 12 of the TTR detection system 10 through the fiber 11 and the like, and is mounted on the reticle stage 5 through the beam splitter 13, the relay lens 14, the mirror 15, and the objective lens 16. The mark 50a of the reticle reference plate 50 is illuminated. The position of the mark 50 a in the Z direction is almost the same as the pattern surface of the reticle 6. The mark 50a is a measurement mark in the XY directions. A reflected image from the illuminated mark 50 a is imaged on an image sensor 18 such as a CCD via the objective lens 16, the mirror 15, the relay lens 14, and the imaging optical system 17.
Further, the mark 80a on the wafer reference plate 80 provided on the wafer stage 8 is illuminated by the mark 50a on the reticle reference plate 50 and the light passing through the projection optical system PL. The mark 80a is a measurement mark in the XY directions. A reflected image from the illuminated mark 80a is formed on the pattern surface of the reticle reference plate 50 through the projection optical system PL, and further, the objective lens 16, the mirror 15, the relay lens 14, and the imaging optics of the TTR detection system 10. An image is formed on an image sensor 18 such as a CCD via a system 17. The image of the mark 50a on the reticle reference plate 50 and the image of the mark 80a on the wafer reference plate 80 are simultaneously detected on the image sensor 18, and the relative position between the reticle stage 5 and the wafer stage 8 is measured.
The objective lens 16 and the mirror 15 of the TTR detection system 10 are mounted on a drive table 19 that can move in the XY directions. By moving the drive table 19 by a drive mechanism (not shown), the TTR detection system 10 can measure at various positions in the XY direction of the reticle 6 and the reticle reference plate 50.

Next, the configuration and detection method of the Fizeau interferometer 20 for measuring the wavefront aberration of the projection optical system PL configured in the same housing as the TTR detection system 10 will be described with reference to FIG.
The Fizeau interferometer 20 is mounted on the reticle stage 5 and mounted on the objective lens front group 29 having a Fizeau surface for forming reference light, the objective lens rear group 30 positioned upstream from the objective lens front group 29, and the wafer stage 8. It comprises a reflection mirror 40 that forms test light.
In the first embodiment, the objective lens rear group 30 and the objective lens 16 as the third objective lens group are arranged on the same drive table 19 configured separately from the reticle stage 5.
Generally, when the exposure light source 1 is an excimer laser, the coherence distance ΔL of the light 1a is several tens of millimeters. On the other hand, since the optical path length of the projection optical system PL to be measured is 1000 mm or more, a Fizeau interferometer cannot be configured using the exposure light source 1. Therefore, the projection exposure apparatus of the first embodiment includes a dedicated light source 21 different from the exposure light source 1 as a light source of an interferometer for wavefront aberration measurement of the projection optical system PL.
The dedicated light source 21 oscillates a laser beam having the same wavelength as the exposure wavelength or a wavelength very close to the exposure wavelength, and has a coherence distance as long as several thousand mm. Have a distance. The laser forms a parallel beam with a collimator lens 25 through a condenser 22 through a condenser lens 23 and a pinhole 24. Since the diameter of the pinhole 24 is set to be about the same as or less than that of the Airy disk determined by the numerical aperture of the collimator lens 25, the light beam emitted from the pinhole 24 becomes an almost ideal spherical wave. Since the collimator lens 25 is designed and manufactured with substantially no aberration, the light beam emitted from the collimator lens 25 is emitted as an ideal plane wave.
In the first embodiment shown in FIG. 1, the light from the dedicated light source 21 may be guided to the pinhole 24 using a polarization maintaining fiber. The formed parallel beam is incident on the objective lens 28 via the half mirror 26 and the mirror 27.

Next, the configuration of the objective lens 28 will be described.
The objective lens 28 is separated into an objective lens front group 29 and an objective lens rear group 30, and the objective lens front group 29 is configured on the reticle stage 5, and the Fizeau interferometer 20 includes an objective configured on the reticle stage 5. The lens front group 29 is included. The final lens surface on the reticle 6 pattern side of the lens constituting the objective lens front group 29 has the same radius of curvature as the distance to the position corresponding to the reticle 6 pattern surface. Further, the final lens surface is configured to transmit a part of the light beam and reflect a part of the light beam.
Hereinafter, the final lens surface is referred to as a Fizeau surface, and a light beam incident on the Fizeau surface is divided into reflected light and transmitted light. The reflected light passes through a mirror 27 and a half mirror 26 as reference light, and further passes through a pupil imaging system composed of a lens 32 and a lens 33 in order to make the pupil of the objective lens 28 and the image sensor 31 conjugate. 31 is led. The transmitted light is incident on the projection optical system PL as test light.
The test light transmitted through the Fizeau surface is on the object plane of the projection optical system PL, and after being imaged at a position on the pattern surface of the reticle 6, the test light is again connected at the position on the wafer 7 surface side by the projection optical system PL. Image. A spherical mirror 40 is disposed on the wafer stage 8, and the radius of curvature of the spherical mirror 40 is the same as the distance from the imaging position of the projection optical system PL. Therefore, the test light reflected by the spherical mirror 40 is condensed again at the imaging position on the wafer 7 side of the projection optical system PL. After the light is collected, the test light returns to the projection optical system PL, passes through the objective lens 28, the mirror 27, and the half mirror 26, and in order to bring the pupil of the projection optical system PL and the CCD light receiving element 31 into a conjugate relationship. The light passes through a pupil imaging system composed of 32 and a lens 33 and is guided to the image sensor 31. Since the test light that has passed through the projection optical system PL interferes with the reference light reflected by the Fizeau surface, the wavefront aberration of the projection optical system PL can be measured.
In the first embodiment, the objective lens rear group 30 and the mirror 27 are mounted on the drive table 19 that can move in the XY directions described in the configuration of the TTR detection system 10. By mounting the objective lens 16 of the TTR detection system 10 and the objective lens rear group 30 of the Fizeau interferometer 20 on the same drive table 19, the relative positions of both lenses are always guaranteed to be constant. That is, for measuring the wavefront aberration of the projection optical system PL with high accuracy, it is necessary to obtain the wavefront error of the Fizeau interferometer 20 and to distinguish it from the wavefront aberration of the projection optical system PL to be measured.

Next, a method for measuring the wavefront error of the Fizeau interferometer 20 itself will be described with reference to FIG.
The wavefront error of the Fizeau interferometer 20 is measured using the spherical mirror 41 configured on the reticle 6 side of the lens barrel 60 holding the projection optical system PL. Similar to the Fizeau surface, the center of curvature of the spherical mirror 41 is located in the same plane as the pattern surface of the reticle 6 (that is, the object surface of the projection optical system PL). The spherical mirror 41 is arranged away from the optical axis of the projection optical system PL by a distance that does not block the exposure light from the exposure illumination system 4 in the Y direction that is the scanning drive direction of the reticle stage 5. The objective lens front group 29 formed on the reticle stage 5 is moved horizontally on the spherical mirror 41 by driving the reticle stage 5. The objective lens rear group 30 is moved by the drive table 19 together with the mirror 27, and the objective lens rear group 30 is moved horizontally on the spherical mirror 41. In other words, the optical axes of the objective lens front group 29 and the objective lens rear group 30 of the objective lens 28 are substantially aligned on the spherical mirror 41. When wavefront aberration measurement is performed in this state, the test light transmitted through the Fizeau surface is reflected by the spherical mirror 41 without being incident on the projection optical system PL. The reflected light passes through the objective lens front group 29, the objective lens rear group 30, the mirror 27, and the half mirror 26, and further passes through a pupil imaging system including the lens 32 and the lens 33, and is guided to the image sensor 31. By the above operation, the error of the wavefront of the Fizeau interferometer 20 itself can be measured.

After measuring the wavefront error of the Fizeau interferometer 20 itself, when measuring the wavefront aberration of the projection optical system PL, it is necessary to prevent the obtained wavefront error of the Fizeau interferometer 20 itself from changing. For this purpose, the objective lens front group 29 and the objective lens rear group 30 are constituted by the reticle stage 5 and the drive table 19 which are different drive systems, and the objective lens front group 29 and the objective lens rear group 30 at the time of driving generated. The optical axis deviation between them must be measured and corrected.
The measurement of the deviation of the optical axis can be performed using the TTR detection system 10. The relative position of the objective lens front group 29 and the mark 50a of the reticle reference plate 50 is always constant on the reticle stage 5, and the relative position of the objective lens rear group 30 and the objective lens 16 of the TTR detection system 10 is on the drive table 19. Always constant. After the wavefront error measurement of the Fizeau interferometer 20 is performed, the mark 50a of the reticle reference plate 50 is observed by the TTR detection system 10 without driving the reticle stage 5 and the drive table 19, and the imaging position on the image sensor 18 is observed. Measure and memorize.
Next, in order to measure the wavefront aberration of the projection optical system PL, the objective lens front group 29 and the objective lens rear group 30 are horizontally moved on the projection optical system PL in the Y direction by driving the reticle stage 5 and the drive table 19, respectively. . In this state, the mark 50a on the reticle reference plate 50 is again observed with the TTR detection system 10, and the imaging position on the image sensor 18 is measured. The reticle stage 5 or the drive table 19 is corrected and driven so that the measurement result of the imaging position substantially matches the measurement result when the wavefront error of the Fizeau interferometer 20 is measured. By performing the correction drive, the wavefront error of the Fizeau interferometer 20 is reproduced, so that the wavefront aberration of the projection optical system PL can be measured with high accuracy.
In the first embodiment, the distance between the objective lens front group 29 and the mark 50a on the reticle reference plate 50 and the distance between the objective lens rear group 30 and the objective lens 16 of the TTR detection system 10 are the same.
Therefore, the TTR detection system 10 is measured without driving the reticle stage 5 and the drive table 19 in a state where the optical axes of the objective lens front group 29 and the objective lens rear group 30 are substantially matched.

  In the modification of the first embodiment, the distance between the objective lens front group 29 and the mark 50a on the reticle reference plate 50 and the distance between the objective lens rear group 30 and the objective lens 16 of the TTR detection system 10 may be different. it can. In this case, when observing the mark 50a with the TTR detection system 10, the reticle stage 5 whose position is controlled with high accuracy and reproducibility by the laser interferometer is driven by the difference in distance to measure the mark 50a. Do. After the measurement of the mark 50a, if the reticle stage 5 is driven to the original position with a reproducible distance difference, the relative position change between the objective lens front group 29 and the objective lens rear group 30 before and after the reticle stage 5 is driven is changed. Does not occur. The mark 50a may be measured by the TTR detection system 10 using the driving of the reticle stage 5 as described above when measuring the wavefront error of the Fizeau interferometer 20 and measuring the wavefront aberration of the projection optical system PL.

Next, Embodiment 2 of the present invention will be described with reference to FIG.
In the second embodiment, the drive table 19 includes a yawing measurement system that measures the yawing amount with respect to the drive axis direction when the drive table 19 is driven. That is, a means for measuring a yawing (rotation about the Z axis) error of the drive shaft (Y drive shaft) with respect to the arrangement direction (Y direction) of the arrangement of the objective lens 16 and the objective lens rear group 40 on the drive table 19 is provided.
FIG. 4A is a diagram showing the state of the drive table 19 when the wavefront error measurement of the Fizeau interferometer 20 itself is performed, and the vertical direction on the paper is the Z + direction. The arrangement of the entire projection exposure apparatus of the second embodiment is in the state shown in FIG. The optical axes of the objective lens front group 29 and the objective lens rear group 30 of the Fizeau interferometer 20 are substantially matched. At this time, there is a reticle reference plate mark 50a in the observation field of the objective lens 16 of the TTR detection system 10, and the position thereof is stored as a position on the image sensor 18 of the TTR detection system 10. Further, the yawing state of the drive table 19 is stored by the yawing measurement system 70. The yawing measurement system 70 measures the position of the drive table 19 in the X direction at two locations, and the yawing state is measured.

Next, FIG. 4B is a diagram showing a state of the drive table 19 when the reticle stage 5 and the drive table 19 are driven in the Y direction in order to perform wavefront measurement of the projection optical system PL.
The arrangement of the entire projection exposure apparatus of the second embodiment is in the state shown in FIG. The mark 50a of the reticle reference plate 50 is within the observation field of the objective lens 16 of the TTR detection system 10, and the position thereof is the position on the image sensor 18 of the TTR detection system 10 stored in FIG. It is reproduced. However, when the yawing state is changed by driving the drive table 19 in the Y direction, the relative positions of the optical axes of the objective lens front group 29 and the objective lens rear group 30 of the Fizeau interferometer 20 are the same as those of the Fizeau interferometer 20 itself. It is different from the time of wavefront error measurement. In order to reproduce the relative positions of the optical axes of the objective lens front group 29 and the objective lens rear group 30, the reticle stage 5 is rotated about the Z axis by the yawing amount ΔX of the drive table 19 measured by the yawing measurement system 70. It is only necessary to rotationally drive.
In the modification of the second embodiment shown in FIG. 5, the drive table 19 is provided with two sets of linear scale heads 71a and 72a and scales 71b and 72b for measuring the drive amount in the Y direction. When the drive table 19 is driven in the Y direction, the yawing error amount can be obtained from the difference ΔY between the drive amount measurement values of the two sets of linear scale heads 71a and 72a. As described above, the yawing measurement system 70 of the drive table 19 may be in various other forms.

Next, Embodiment 3 of the present invention will be described with reference to FIG. 6 and FIG. 7. Embodiment 3 is a mark of a reticle reference plate 50 which is an original reference plate formed on a reticle stage 5 which is an original stage. Is composed of two pairs, and the TTR detection system 10 which is a TTR microscope is composed of two systems each capable of observing the two pairs of marks, and the drive table 19 includes two pairs of the TTR detection system 10. The objective lens 16 and the objective lens rear group 30 of the Fizeau detection system 20 are included.
FIG. 7A is a diagram showing the state of the drive table 19 when the wavefront error measurement of the Fizeau interferometer 20 itself is performed, and the vertical direction on the paper is the Z + direction. The optical axes of the objective lens front group 29 and the objective lens rear group 30 of the Fizeau interferometer 20 are substantially matched. At this time, there are two pairs of marks 50a on the reticle reference plate 50 in the observation field of view of each of the two pairs of objective lenses 16 of the TTR type detection system 10, and each of the TTR type detection systems 10 has two pairs of marks 50a. The mark 50a corresponding to 10 is measured.
Next, FIG. 7B is a diagram showing the state of the drive table 19 when the reticle stage 5 and the drive table 19 are driven in the Y direction in order to perform the wavefront measurement of the projection optical system PL. Even if a yawing error occurs in the drive stage 19 as shown in FIG. 7B, the two pairs of marks 50a are measured by the two pairs of TTR detection systems 10 so that the relative position with respect to the drive stage 19 can be reproduced. The reticle stage 5 may be rotated around the Z axis by the yawing amount ΔY of the drive table 19.
Further, the example in which the objective lens front group 29 of the Fizeau interferometer 20 is configured on the reticle stage 5 has been described as the third embodiment. However, as with the reticle 6, the objective lens front group 29 may be detachable from the reticle stage 5. Good.
As described above, in the Fizeau interferometer, by suppressing fluctuations in the wavefront aberration of the Fizeau interferometer itself, the wavefront error amount of the Fizeau interferometer itself can be corrected with high accuracy when measuring the wavefront aberration of the projection optical system. The wavefront aberration of the projection optical system can be obtained. Further, by incorporating the Fizeau interferometer in the projection exposure apparatus, the characteristics of the projection optical system can be measured in the projection exposure apparatus. Therefore, for example, it is possible to quickly cope with a change in the characteristics of the projection optical system, such as correction of the projection optical system and stop of the exposure operation.

(Example of device manufacturing method)
A device (semiconductor integrated circuit element, liquid crystal display element, etc.) includes a step of exposing a substrate (wafer, glass plate, etc.) coated with a photosensitive agent using the exposure apparatus of any of the embodiments described above, and the substrate The film is formed and manufactured through a process of developing and other known processes. Other well known processes include etching, resist stripping, dicing, bonding, packaging, and the like.

It is a schematic block diagram of the exposure apparatus of Example 1 of this invention. It is a schematic block diagram of the exposure apparatus of Example 1 of this invention. It is a schematic block diagram of the exposure apparatus of Example 1 of this invention. It is a schematic block diagram of the yawing measurement system of the drive table of the projection exposure apparatus of Example 2 of this invention. It is a schematic block diagram of the yawing measurement system of the drive table of the projection exposure apparatus of the modification of Example 2 of this invention. It is a fragmentary perspective view of the projection exposure apparatus of Example 3 of this invention. It is a schematic block diagram of the yawing measurement system of the drive table of the projection exposure apparatus of Example 3 of invention. It is a schematic block diagram of the projection exposure apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure light source 2 Beam shaping optical system 3 Incoherent unit 4 Exposure illumination system 5 Reticle stage 6 Reticle 7 Wafer 8 Wafer stage 10 TTR system detection system 11 Fiber 12 Illumination part 13 Beam splitter 14 Relay lens 15 Mirror 16 Objective lens 17 Imaging Optical system 18 Image sensor 19 Drive table 20 Fizeau interferometer 21 Dedicated light source 22 Mirror 23 Condensing lens 24 Pinhole 25 Collimator lens 26 Half mirror 27 Mirror 28 Objective lens 29 Objective lens front group 30 Objective lens rear group 31 Imaging element 32 Lens 33 Lens 40 Spherical mirror 41 Spherical mirror 50 Reticle reference plate 50a Mark PL Projection optical system 60 Lens barrel 70 Yawing measurement system 71a Linear scale head 71b Scale 72a Linear scale De 72b scale 80 wafer reference plate 80a mark

Claims (4)

An original stage holding the original, and
A substrate stage for holding the substrate;
From an objective lens front group having a Fizeau surface mounted on the original stage and forming a reference light, an objective lens rear group positioned upstream from the objective lens front group, and a reflection mirror mounted on the substrate stage and forming test light A Fizeau interferometer,
Observe simultaneously the mark of the original reference plate configured on the original stage and the mark of the substrate reference plate configured on the substrate stage through a projection optical system, and measure the relative position of the original stage and the substrate stage, A TTR detection system having a third objective lens group located upstream from the mark on the original reference plate,
In an exposure apparatus that projects and exposes the pattern of the original plate onto the substrate through the projection optical system,
An exposure apparatus, wherein the objective lens rear group and the third objective lens group are arranged on the same drive table configured separately from the original stage.   The exposure apparatus according to claim 1, wherein the drive table includes a yawing measurement system that measures a yawing amount with respect to a drive axis direction when the drive table is driven. Marks on the original reference plate configured on the original stage are composed of two pairs,
The exposure apparatus according to claim 1, wherein the TTR microscope includes two systems in which the two pairs of marks can be observed. A step of exposing the substrate using the exposure apparatus according to claim 1;
Developing the substrate;
Forming a device using the developed substrate. A device manufacturing method comprising:

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