JP3551570B2 - Scanning exposure apparatus and exposure method - Google Patents

Scanning exposure apparatus and exposure method Download PDF

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Publication number
JP3551570B2
JP3551570B2 JP22481395A JP22481395A JP3551570B2 JP 3551570 B2 JP3551570 B2 JP 3551570B2 JP 22481395 A JP22481395 A JP 22481395A JP 22481395 A JP22481395 A JP 22481395A JP 3551570 B2 JP3551570 B2 JP 3551570B2
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Prior art keywords
scanning
mask
image
exposure
reticle
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JPH0950955A (en
Inventor
哲夫 谷口
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株式会社ニコン
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Priority to JP22481395A priority Critical patent/JP3551570B2/en
Priority claimed from US08/691,377 external-priority patent/US5841520A/en
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    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70Exposure apparatus for microlithography
    • G03F7/70216Systems for imaging mask onto workpiece
    • G03F7/70358Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention sequentially exposes the circuit pattern on the photosensitive substrate by synchronously scanning the mask and the photosensitive substrate with respect to an illumination area on the mask while illuminating the mask on which the circuit pattern is formed. The present invention relates to a scanning exposure apparatus, and more particularly, to a scanning exposure apparatus and an exposure method capable of accurately measuring an imaging characteristic of a pattern image of a mask formed by scanning a mask and a substrate before actual exposure. .
[0002]
[Prior art]
Conventionally, a projection exposure apparatus has been used as an apparatus for forming a circuit pattern of a semiconductor integrated circuit or a liquid crystal substrate on a semiconductor wafer by a photolithography technique. Such a projection exposure apparatus irradiates a reticle (mask) with illumination light uniformized by an illumination system to form a reticle pattern image on a photosensitive substrate via a projection optical system. This type of apparatus requires high-precision imaging characteristics in order to form a fine circuit pattern, and furthermore, a layer to be subjected to an exposure process in order to expose a plurality of patterns in the same region on the substrate by overlapping. High overlay accuracy is required between the layer and the layer that has been exposed last time. For this reason, before executing the exposure, the imaging characteristics of the projection optical system are evaluated in advance, and the lens elements of the projection optical system are relatively moved in the optical axis direction so as to obtain appropriate imaging characteristics. Corrections have been made such as changing the distance between the reticle and the principal point of the projection optical system. As a method of evaluating the imaging characteristics of the projection optical system in advance, prior to actual exposure, a photoresist on a wafer is exposed with a test reticle pattern in which a plurality of marks are drawn, and mark coordinates are obtained from the developed test pattern image. Has been conventionally performed by observing an image and comparing it with mark coordinates on a reticle. However, such an evaluation method has the drawbacks that it requires time and labor due to the necessity of preliminary exposure and development steps, and requires a special device for measuring an image. For this reason, the present applicant has disclosed in Japanese Patent Application Laid-Open No. S59-94032 that a photoelectric sensor is provided on a stage on which a photosensitive substrate is mounted, and a test pattern of a reticle formed from a sensor output via a projection optical system. A method for directly observing location information has been disclosed. According to this method, not only initial adjustment of the apparatus, but also changes with time of the apparatus, changes in the external environment such as atmospheric pressure and temperature, changes in the absorption characteristics of illumination light by the imaging optical system, or illumination conditions of the reticle (solid It is possible to easily observe a change in imaging characteristics caused by a change in device conditions such as an angle, etc., and to correct the imaging characteristics based on the observation result. Therefore, a recent projection exposure apparatus is equipped with a mechanism for measuring the imaging characteristics of the imaging optical system in order to execute this method.
[0003]
FIG. 5 shows an example of an imaging characteristic measurement mechanism of the imaging optical system and an observation result. FIG. 5A is a view showing a schematic structure of an apparatus for exposing a mark pattern on a reticle R onto a wafer W as a photosensitive substrate via a projection optical system PL. As shown in the figure, the wafer stage WST includes a photoelectric sensor 202 having a two-dimensional resolution at a location different from the wafer holder 5 on which the wafer W is placed. While the imaging characteristics of the optical system are measured, the photoelectric sensor 202 is positioned directly below the projection optical system PL, and the wafer stage WST is positioned so that the wafer W is positioned outside the exposure area of the projection optical system PL. . The photoelectric sensor 202 is, for example, a CCD or an image pickup tube, and can electrically capture a two-dimensional image. In general, the position resolution of these photoelectric sensors 202 is lower than the resolution of the image of the projection exposure apparatus, and sufficient accuracy cannot be obtained even if they are directly formed on the photoelectric sensors 202 (this is because the CCD etc. It is also understood from being manufactured by an exposure apparatus). For this reason, the image of the test pattern of the reticle R by the projection optical system PL is once enlarged by about 100 to 400 times by the enlargement optical system 201 and then received by the photoelectric sensor 202. FIG. 5B shows a mark pattern (test pattern) 203 of the reticle R received by the photoelectric sensor 202. In order to determine the imaging characteristics of the projection optical system PL from this image, for example, the detection signal intensity in the scanning line 204 direction is measured, and the line width a or the contrast b is obtained from the measurement result as shown in FIG. , Center coordinates c and the like. Further, based on these measurement results, the aberration (for example, coma, spherical aberration) of the projection optical system PL or the focal position, magnification, distortion, and the like can be obtained by calculation.
[0004]
[Problems to be solved by the invention]
The above-described method for measuring the imaging characteristics has been used in a batch exposure method (full field method) represented by a so-called step-and-repeat method. However, in recent years, a part of the pattern area of the reticle is illuminated in a slit or arc shape, and the reticle is scanned with respect to the illumination area. A so-called slit scan exposure type exposure apparatus has been developed in which a reticle pattern is sequentially exposed on the photosensitive substrate by scanning the photosensitive substrate in synchronization with the reticle scanning. In this slit scan exposure method, the illumination area on the reticle is smaller than in the batch exposure method, and only a part of the image field of the projection optical system is used for exposure, so that distortion of the projected image and uniformity of illuminance can be easily adjusted. There is an advantage that there is. In addition, the enlargement of the exposure area is required in accordance with the increase in the area of the semiconductor substrate and the like. There is also an advantage that can be increased.
[0005]
However, unlike the batch exposure method, the slit scan exposure method moves the reticle over the illumination area during the formation of one image, so that even one image is formed by light rays that have passed through different parts of the imaging optical system. Is formed. That is, by scanning the reticle with respect to the illumination area, an image is formed on the photosensitive substrate through a different part of the projection optical system while a certain point on the reticle pattern passes through the illumination area. On the other hand, in the conventional method for measuring the imaging characteristics, a test pattern image of the reticle formed through a certain optical path in the imaging optical system is observed by the photoelectric conversion element. Therefore, as described above, in the slit scan method in which an image is formed by passing through a plurality of continuous portions of the imaging optical system, it is possible to obtain an imaging characteristic only from a fixed area of the projection optical system. However, this does not reflect the imaging characteristics in actual exposure (the adjustment of the imaging optical system itself may be performed by looking at a still image, as in the past). Specifically, for example, if the distortions of the images formed through a plurality of portions of the imaging optical system are different from each other, the images are spread and exposed, and the contrast deteriorates.
[0006]
Further, not only the problem of the imaging optical system described above, but also the synchronization deviation of the scanning speed of the reticle and the photosensitive substrate, the rotation error of the reticle during the scanning of the reticle, and the vertical movement thereof deteriorate the imaging characteristics. Further, a deviation in the positional relationship between the reticle and the photosensitive substrate due to the vibration of the apparatus due to the scanning operation also deteriorates the imaging characteristics. In particular, a projection exposure apparatus illuminates an overlay alignment mark formed in advance on a photosensitive substrate and receives reflected light from the mark in order to overlay a plurality of patterns on the same region of the substrate and expose the same. An alignment system for detecting the position and displacement of the lever is provided. The baseline indicating the distance between the optical axis of the alignment system and the optical axis of the projection optical system is measured with the wafer stage and the reticle stage stationary at the time of detecting an alignment mark on the wafer, but during actual exposure. Since the reticle pattern is projected and exposed on the wafer by moving the wafer stage and the reticle stage together, there is a possibility that the baseline measured at rest and the baseline obtained during scanning may be different. These problems are unique to the slit scan exposure type apparatus, and cannot be measured while the mask stage is kept still as in the conventional measurement of the imaging characteristics.
[0007]
The present invention has been made to solve the above problems, and an object of the present invention is to accurately detect the position or displacement of a mark pattern on a mask or its projected image before actual exposure. It is an object of the present invention to provide a scanning exposure apparatus provided with a mechanism capable of performing the scanning.
[0008]
It is another object of the present invention to provide a scanning exposure apparatus having a mechanism capable of accurately measuring the imaging characteristics of a projection optical system or the imaging state of a pattern image of a mask before actual exposure. .
[0009]
Another object of the present invention is to provide a scanning exposure apparatus having a mechanism capable of accurately measuring a baseline of an alignment system before actual exposure.
[0010]
Still another object of the present invention is to provide a scanning type exposure apparatus provided with a mechanism capable of accurately positioning a mask and a photosensitive substrate before actual exposure.
[0011]
Still another object of the present invention is to provide, prior to the actual exposure step, the position of the mark pattern on the mask or the projected image thereof while the mask and the photosensitive substrate are synchronously scanned with respect to the illumination area on the mask. It is an object of the present invention to provide a scanning exposure method capable of accurately detecting a displacement and an imaging characteristic.
[0012]
Still another object of the present invention is to provide, in the above scanning exposure method, an image forming characteristic of a projection optical system which is obtained in a state where a mask is stationary with respect to an illumination area, based on the position or displacement of the mark pattern or its projected image. Another object of the present invention is to provide a scanning exposure method capable of correcting an image formation state of a mask pattern.
[0013]
In the text, the term "illumination area" refers to an area on a mask (reticle) defined by illuminating light, and its size is usually limited by a field stop or the like arranged in an illumination optical system. Is done. The term “exposure area” refers to an area on a photosensitive substrate that is exposed when illumination light is irradiated through a projection optical system, and the exposure area has a conjugate relationship (an imaging relationship) with respect to the illumination area and the projection optical system. )It is in. In a scanning exposure apparatus, usually, a mask moves in a one-dimensional direction with respect to the illumination area, and the photosensitive substrate moves in a direction opposite to the one-dimensional direction with respect to the exposure area in synchronization with the mask. Is performed.
[0014]
[Means for Solving the Problems]
According to a first aspect of the present invention, a mask stage for scanning an illumination area on a mask with the mask, a projection optical system for projecting an image of a pattern on the mask onto a photosensitive substrate, and the illumination area And a substrate exposure stage that scans the photosensitive substrate for an exposure area conjugate with respect to the projection optical system,
A light receiving unit is provided on the substrate stage, and an image of a mark pattern on the mask is photoelectrically detected. Photoelectric detection Means,
While scanning the light receiving portion with respect to the exposure region in synchronization with scanning the mark pattern with respect to the illumination region, Photoelectric detection Combining means for combining signals output from the means,
The above-described scanning type exposure apparatus is characterized in that a position or a position shift of an image of the mark pattern is detected based on an output of the synthesizing means. The scanning exposure apparatus of the present invention Photoelectric detection By providing the light receiving portion of the means, the mask can be moved under the condition of actual scanning exposure, that is, under the dynamic condition of moving the mask stage and the substrate stage for scanning the mask and the substrate. The image of the test mark pattern can be measured in advance. Photoelectric detection By providing means for combining the outputs from the means, an image of a mark pattern formed by transmitting light through various parts of the projection optical system during one scan in an actual exposure is provided as a combined image. Can be drawn as From this composite image, the position and positional deviation of the image formed by actual scanning exposure can be known. Such a displacement is a displacement caused by movement of a stage for scanning or the like, and cannot be obtained by a conventional static imaging characteristic measuring method.
[0015]
The scanning exposure apparatus further includes an alignment system that illuminates the alignment mark on the photosensitive substrate, receives reflected light from the alignment mark, and detects the position or displacement of the alignment mark, and the detected mark pattern image And the light irradiation position of the alignment system can be used as the baseline of the alignment system. In the present invention, by defining the difference between the position of the mark pattern image of the mask detected by the light receiving unit and the light irradiation position of the alignment system light source as the baseline of the alignment system, the photosensitive substrate can be used during overlay exposure. Alignment with the mask can be performed more accurately.
[0016]
Further, the scanning exposure apparatus further includes a detection unit configured to detect at least one of a position and a rotation amount of the pattern image of the mask based on a position or a displacement of each image of the plurality of mark patterns on the mask. The alignment between the mask and the photosensitive substrate can be performed using the detection result of the detection unit. For example, instead of detecting the reticle position (mark pattern position) and the amount of rotation when the mask is stationary, the reticle position when the mask stage is scanning during actual exposure is detected, and the wafer position is detected by the alignment sensor. Are superimposed on the basis of the measurement result of the above and the reticle position information at the time of scanning. Further, the reticle or wafer is rotated to cancel the rotation error. Thus, the wafer position can be adjusted in relation to the reticle position at the time of actual exposure. Further, the scanning type exposure apparatus may further include an arithmetic unit for calculating an imaging characteristic of the projection optical system based on a position or a position shift of each image of the plurality of mark patterns on the mask.
[0017]
According to a second aspect of the present invention, a mask stage for scanning the mask with respect to an illumination area on the mask, a projection optical system for projecting an image of a pattern on the mask onto a photosensitive substrate, and the illumination area And a substrate exposure stage that scans the photosensitive substrate for an exposure area conjugate with respect to the projection optical system,
A light receiving unit is arranged on the substrate stage, and photoelectrically detects an image of a mark pattern on the mask. Photoelectric detection Means;
While scanning the light receiving portion with respect to the exposure region in synchronization with scanning the mark pattern with respect to the illumination region, Photoelectric detection Combining means for combining signals output from the means;
Calculating means for calculating an image forming state of the image of the mark pattern based on an output of the synthesizing means. The scanning exposure apparatus of the present invention Photoelectric detection By providing the light receiving section of the means, the image of the test mark pattern of the mask can be measured in advance under the conditions of the actual scanning exposure. Photoelectric detection By providing means for combining the outputs from the means, an image of a mark pattern formed by transmitting light through various parts of the projection optical system during one scan in an actual exposure is provided as a combined image. Can be drawn as Using this composite image, the imaging characteristics of an image formed by actual scanning exposure, such as magnification and contrast, can be known by calculation.
[0018]
It is preferable that the scanning type exposure apparatus further includes a correction unit for correcting an imaging characteristic of the projection optical system according to a calculation result of the calculation unit. The correction unit may be a stage controller that controls a scanning speed or a scanning direction of the mask stage and the substrate stage. By changing the moving speed of each stage by this stage controller, it is possible to obtain an optimum imaging characteristic.
[0019]
In the scanning exposure apparatus of the present invention, Photoelectric detection The means may include an imaging element having a light receiving surface disposed on a surface substantially conjugate with the light receiving unit, and an enlargement optical system for enlarging an image of the mark pattern to form an image on the light receiving surface. it can. The mechanism in which the energy of light is accumulated in the photosensitive agent during scanning when the photosensitive substrate is exposed by the exposure operation to form an image and the mechanism in which the image sensor forms an image by photoelectric detection can be considered to be the same. By using an image sensor, an image formed at the time of actual exposure can be predicted.
[0020]
According to a third aspect of the present invention, the mask is scanned with respect to an illumination area on the mask while illuminating the mask, and a photosensitive substrate is exposed with respect to an exposure area conjugate with the illumination area and the projection optical system. In the scanning exposure method of exposing the pattern of the mask on a photosensitive substrate through a projection optical system by scanning in synchronization with the scanning of the mask,
Prior to the exposure, an image of a mark pattern formed on the mask is detected instead of the photosensitive substrate. detection means Light-receiving part Is scanned in synchronization with the scanning of the mask,
Said During the scan, The detection By combining the signals output from the means , The scanning exposure method is provided, wherein a position or displacement of a mark pattern image of a mask during scanning is obtained. For the illumination area of the mask detection Means, for example, by synchronously scanning the light receiving portion of the image sensor and the mask, to form an actual scan exposure, that is, image a test pattern of the mask under dynamic conditions in which the mask stage and the substrate stage move. Can be done. From the obtained image, the positional shift of the image caused by using the scanning exposure method can be known prior to the actual exposure.
[0021]
In the above scanning exposure method, an image of the mark pattern in the exposure area is detected while illuminating a mark pattern of the mask with the mask fixed to the illumination area, and the image position of the detected mark pattern is detected. It is preferable that the method further includes correcting the information based on the position or displacement of the mark pattern image of the mask during the obtained scan. Information about an image position measured under a conventional static condition as shown in FIG. 5 is corrected in advance by a position or a position shift measured under a dynamic condition of scanning exposure accompanying movement of a mask stage and a substrate stage. be able to. Using the corrected position information, an imaging characteristic or the like can be predicted before actual exposure, and exposure conditions can be corrected by various methods at the time of exposure.
[0022]
According to a fourth aspect of the present invention, the mask is scanned with respect to an illumination area on the mask while illuminating the mask, and a photosensitive substrate is exposed with respect to an exposure area conjugate with the illumination area and the projection optical system. In the scanning exposure method of exposing the pattern of the mask on a photosensitive substrate through a projection optical system by scanning in synchronization with the scanning of the mask,
Prior to the exposure, an image of a mark pattern formed on the mask is detected instead of the photosensitive substrate. detection Scanning the light receiving portion of the means in synchronization with the scanning of the mask, and during the scanning, detection Combining the signals output from the means to obtain a mark pattern image of the mask during scanning, and calculating the imaging characteristics of the projection optical system from the obtained mark pattern image. Is provided. According to this method, the test pattern of the mask can be imaged under actual scanning exposure, that is, under dynamic conditions in which the mask stage and the substrate stage move, and the imaging characteristics can be obtained in advance. As a result, it is possible to know in advance the difference between the imaging characteristics obtained when the mask stage and the reticle stage are stationary and the imaging characteristics during actual exposure, and to adjust the imaging speed measured under dynamic conditions by adjusting the stage moving speed. Image characteristics can be corrected.
[0023]
According to a fifth aspect of the present invention, there is provided a method of manufacturing a micro device using the scanning exposure apparatus of the present invention. Thereby, a micro device can be manufactured with high precision.
[0024]
【Example】
Hereinafter, an embodiment of a scanning exposure apparatus according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of a scanning projection exposure apparatus that exposes a reticle R and a wafer W while scanning the reticle R in synchronization with an illumination area of the reticle R. The projection exposure apparatus includes a light source and an illumination optical system (both not shown), a reticle stage RST for moving the reticle R in the scanning direction, a projection optical system PL for projecting a pattern image formed on the reticle R onto the wafer W, and a wafer. It mainly includes a wafer stage WST that moves W in synchronization with the scanning of the reticle R, alignment systems 30 to 35 for aligning the wafer, and a photoelectric sensor 3 that measures the imaging characteristics. The light source and the illumination optical system are generally arranged above the reticle stage RST in FIG. As the illumination light source, for example, an ultraviolet light source such as an i-line or a g-line which is an emission line of an ultra-high pressure mercury lamp, KrF, ArF excimer laser light, or metal vapor laser light is used. The illumination optical system is a fly-eye lens to achieve uniform illuminance, a shutter to open and close the optical path, and a variable blind to limit the illumination area as well as The reticle R on which a circuit pattern or the like is drawn is illuminated by illumination light IL from a light source and an illumination optical system at a substantially uniform illuminance and a predetermined solid angle. In recent years, in order to increase the resolution, Zonal lighting Or, it is configured to be capable of oblique illumination or the like.
[0025]
The reticle stage RST is installed above the projection optical system PL, and can be moved at a predetermined scanning speed in the scanning direction (X direction) by a reticle driving unit (not shown) composed of a linear motor or the like. The reticle stage RST is provided with a movable mirror 6 that reflects the laser beam from the interferometer 7 fixed to the end in the X direction, and the position of the reticle stage RST in the scanning direction is, for example, in units of 0.01 μm by the interferometer 7. Measured. The measurement result of the interferometer 7 is sent to the stage controller 14, and the reticle stage RST is always positioned with high accuracy. On reticle stage RST, a reticle holder (not shown) is provided, and reticle R is mounted on the reticle holder by being attracted by a vacuum chuck or the like. Above the reticle stage RST, a reticle alignment system (not shown) opposed to the optical axis AX is mounted. The initial position of reticle stage RST is determined so as to be accurately positioned at a predetermined reference position. Therefore, the position of the reticle R can be adjusted with sufficiently high accuracy only by measuring the position of the reticle stage RST by the movable mirror 6 and the interferometer 7. The drive unit of reticle stage RST is controlled by stage controller 14.
[0026]
On reticle stage RST, reticle R is illuminated by a rectangular (slit-shaped) illumination area whose length is in a direction (Y direction) perpendicular to the scanning direction (X direction) of reticle R. This illumination area is defined by a field stop (not shown) arranged above the reticle stage and at or near a plane conjugate with the reticle R.
[0027]
The illumination light having passed through the reticle R is incident on the projection optical system PL, and a circuit pattern image of the reticle R by the projection optical system PL is formed on the wafer W coated with a photosensitive agent (photoresist). A plurality of lens elements are accommodated in the projection optical system PL such that the optical axis AX is a common optical axis. The projection optical system PL is provided with a flange portion 24 on the outer peripheral portion and at the center in the optical axis direction, and is fixed to the mount of the exposure apparatus main body by the flange portion 24.
[0028]
The projection magnification of the pattern image of the reticle R projected on the wafer W is determined by the magnification and arrangement of the lens elements of the projection optical system PL, and is usually reduced to 1/5 or 1/4 by the projection optical system PL.
[0029]
A reticle pattern in a slit-shaped illumination area (center substantially coincides with optical axis AX) on reticle R is projected onto wafer W via projection optical system PL. Since the wafer W has an inverted image relationship with the reticle R via the projection optical system PL, if the reticle R is scanned at a speed Vr in the −X direction (or + X direction) during exposure, the wafer W Scanning is performed in the opposite + X direction (or -X direction) at a speed Vw in synchronization with the reticle R, and the entire pattern of the reticle R is sequentially exposed on the entire shot area on the wafer W. The scanning speed ratio (Vr / Vw) is determined by the reduction magnification of the projection optical system PL described above.
[0030]
Wafer W is vacuum-sucked on wafer holder 5 held on wafer stage WST. Wafer stage WST is configured to be movable not only in the above-described scanning direction (X direction) but also in a direction (Y direction) perpendicular to the scanning direction so that a plurality of shot areas on the wafer can be scanned and exposed. The operation of scanning each shot area on the wafer W and the operation of moving to the exposure start position of the next shot area are repeated. Wafer stage WST is also capable of fine movement in the optical axis AX direction (Z direction) of projection optical system PL. Further, wafer stage WST can be inclined with respect to optical axis AX by a leveling stage (not shown). Wafer stage WST is driven by a wafer stage driving unit (not shown) such as a motor, and its movement speed is adjusted according to the ratio (Vr / Vw), and moves in synchronization with reticle stage RST. A movable mirror 8 is fixed to an end of wafer stage WST, and a laser beam from interferometer 9 is reflected by movable mirror 8, and reflected light is detected by interferometer 9 so that wafer stage WST can be moved in the XY plane. The coordinate position is constantly monitored. The reflected light from the movable mirror 8 is detected by the interferometer 9 with a resolution of, for example, about 0.01 μm. The wafer stage driving unit is controlled by the stage controller 14, and drives the wafer stage WST in synchronization with the reticle stage RST. The scanning of each stage and the adjustment of the projection optical system PL accompanying the scanning are collectively managed by the stage controller 14.
[0031]
The scanning exposure apparatus shown in FIG. 1 includes a wafer alignment system for exposing a pattern already exposed on the wafer W with a new pattern with high accuracy. As the wafer alignment system, the positions of alignment marks on the wafer W are read by optical wafer alignment systems 30 to 35 provided separately from the projection optical system PL, and the positions at which overlay exposure is performed are determined. As the light source 30, a laser, a halogen lamp, or the like that generates light having a wavelength that is insensitive to the photoresist film on the wafer W is used. The illumination light emitted from the light source 30 illuminates the alignment mark on the wafer W by the mirror 35 via the half mirror 33 and the mirror 34. The reflected light or the diffracted light from the alignment mark on the wafer W passes through a path opposite to the illumination light, passes through the half mirror 33, and is photoelectrically converted in the light receiving unit 31. The signal from the light receiving section 31 is amplified to a sufficient output by the amplifier 31 and sent to an alignment control system (not shown). The optical axis AX of the projection optical system PL and the optical axis AX2 of the alignment system are set as close as possible and are separated by a certain interval. By maintaining this interval stably, an accurate positional relationship between the pattern of the reticle R and the shot area of the wafer W is maintained when the overlay exposure is performed. The optical axis AX and the optical axis AX2 are usually called a base line of an alignment system. In the present invention, the base line is defined based on a mark formed on the reticle R as described later.
[0032]
The projection exposure apparatus shown in FIG. 1 is a position sensor (wafer W) that includes a projector 10 that irradiates a light beam from an oblique direction to an image plane of a projection optical system PL and a light receiver 11 that receives light reflected from the image plane. Z direction sensor). This position sensor can be configured to project, for example, a slit image or a pinhole image from the projector 10 onto the wafer W and receive the reflected light through the slit or the pinhole. When the wafer W is positioned on the image plane, the adjustment is performed so that the reflected light enters the slit or the pinhole. By providing a plurality of these sensors, after detecting the inclination of the surface of the wafer W, the wafer level WST is moved by the above-mentioned leveling stage so that the entire exposure area on the wafer W coincides with the optimum image plane of the projection optical system PL. It is also possible to perform the correction by tilting. As the light emitted from the light projector, light having a wavelength that does not expose the photosensitive agent is selected.
[0033]
Here, the scanning exposure operation of the scanning exposure apparatus will be described with reference to FIG. FIG. 2A is a conceptual diagram of the reticle R as viewed from above, and the rectangular illumination area IA is defined in a circle indicating the image field of the projection optical system PL. By moving the reticle R in the scanning direction (X direction) with respect to the illumination area IA, the patterns on the reticle R are sequentially illuminated, and all the patterns existing in the scanning direction of the reticle R by one scan. Be illuminated. The illumination time is determined by the time required for each pattern to cross the illumination area IA, that is, the size of the pattern and the scanning speed. The scanning speed is determined based on the sensitivity of the photosensitive agent, the intensity of illumination light, and the like. FIG. 2A shows a case where the reticle R is scanned in the X direction at the speed Vr. The reticle pattern irradiated in the illumination area IA is formed on the exposure area EA on the wafer W at the reduction magnification of the projection optical system PL. This state is shown in FIG. 2B when the wafer W is viewed from above. As described above, the speed Vw of the wafer W is determined by the speed Vr of the reticle R × the reduction magnification of the projection optical system PL. Since the image on the wafer W has a mirror image relationship with the pattern of the reticle R, the wafer W is opposite to the reticle R. In the -X direction. When one scan of the reticle R is completed, an image of the entire surface of the reticle R is formed on the wafer W in the region SH. By repeating this operation, so-called step-and-scan exposure is performed in which a plurality of patterns of the reticle R are exposed almost over the entire surface of the wafer W.
[0034]
In FIG. 1, a glass plate 1 for imaging measurement is installed on wafer stage WST at a position different from wafer holder 5 at a height substantially coincident with the upper surface of wafer W. The position of the glass plate 1 is adjusted by the Z-direction position sensors (10, 11) and the wafer stage WST so that the upper surface of the glass plate 1 coincides with the image plane of the projection optical system PL. Below the glass plate 1 and inside the wafer stage WST, an enlargement optical system 2 and a photoelectric sensor 3 are installed. According to the exposure method of the present invention, before the actual wafer W is exposed, the glass plate 1 is positioned directly below the projection optical system PL by the movement of the wafer stage WST, and the imaging characteristics are measured. The light beam that has passed through the projection optical system PL forms an image once on the glass plate 1, and then forms an image again on the light receiving surface of the photoelectric sensor 3 via the magnifying optical system 2. On the light receiving surface of the photoelectric sensor 3, an image formed on the glass plate 1 is magnified by the magnification of the magnifying optical system 2 to form an image. The glass plate 1 can be omitted by positioning the upper lens constituting the magnifying optical system 2 on the image plane of the projection optical system PL. Here, if there is an aberration in the magnifying optical system 2, it becomes impossible to distinguish whether the distortion or the like of the image formed on the light receiving surface of the photoelectric sensor 3 is due to the aberration of the projection optical system PL or the aberration of the magnifying optical system 3. Therefore, an optical system having extremely little aberration must be used for the magnifying optical system 2. The configuration of the imaging characteristic measuring system including the magnifying optical system 2 and the photoelectric sensor 3 is the same as the configuration of the conventional static imaging characteristic measuring system shown in FIG. The same magnification and the same type of photoelectric sensor 3 can be used. For this reason, the still image of the projection optical system PL may be measured by moving the photoelectric sensor 3 to an arbitrary position in the exposure area EA and then keeping the wafer stage WST and the reticle stage RST stationary as in the conventional case. The image signal of the photoelectric sensor 3 is taken into the image processing system 4 and processed. The processed image data is sent to the computing unit 12, where the imaging characteristics are computed. As described above, it is necessary for a scanning type exposure apparatus to optimally adjust the imaging characteristics in a stationary state, that is, the imaging characteristics in a state where the reticle R and the wafer W are not scanned before the actual exposure. It is also necessary to correct the imaging characteristics obtained by the calculation using an appropriate correction means. For example, if the magnification obtained by the calculation deviates from the target magnification, a magnification deviation occurs in the non-scanning direction of an image formed by scanning, and the image quality in the scanning direction deteriorates. For this reason, for example, the optical path length of the reticle R and the projection optical system PL is changed, a part of the lens element of the projection optical system PL is driven in the direction of the optical axis AX, or is inclined with respect to the optical axis AX. A known method for correcting magnification and distortion can be used. The shift of the focal position, the inclination of the image plane, and the like are corrected by giving an offset to the position sensors (10, 11) in the Z direction. The present invention provides a method for measuring the imaging characteristics during the scanning exposure and a correction method on the assumption that the imaging characteristics in the stationary state are optimized. Further, in the present invention, as described later, the reticle R is used by using information on the mark position and the imaging characteristics of the reticle R obtained from the measurement of the imaging characteristics measured during the scanning of the reticle R and the wafer stage WST. The mark position and the imaging characteristics of the reticle R measured while the R and the wafer stage WST are stationary can be corrected in advance.
[0035]
Next, a method for measuring the imaging characteristics in the scanning exposure, which is one step of the scanning exposure method of the present invention, using the scanning exposure apparatus shown in FIG. 1 will be described. As the reticle R, a dedicated test reticle on which a test pattern is drawn by a plurality of marks, or a reticle pattern including a plurality of test marks around a manufacturing reticle as shown in FIG. 4 can be used. Alternatively, a dedicated imaging characteristic measurement pattern provided on reticle stage RST may be used. When the traveling speed or the inclination of the reticle R differs depending on the position on the reticle stage RST, a test reticle that can measure almost the entire surface of the reticle stage RST is advantageous. However, if such a dedicated reticle R is used, the reticle exchange operation becomes complicated. Therefore, it is desirable to appropriately use the reticle. In the present invention, as shown in FIG. 4, a reticle R for manufacturing a circuit pattern, wherein four test marks M are provided on two opposing sides outside the reticle pattern area 40. 1 ~ M 8 A reticle pattern containing was used.
[0036]
At the time of measuring the imaging characteristics, the wafer stage WST is moved to form an image of the test mark on the reticle R on the photoelectric sensor 3. Then, the reticle R and the photoelectric sensor 3 are synchronously scanned at the same scanning speed as that during the actual exposure, and the image of the test mark on the reticle R is taken into the image processing system 4 as image data. During this scanning, the photoelectric sensor 3 passes through the exposure area EA (see FIG. 2). The image processing system 4 adds the outputs of the pixels one after another from the obtained image data. When the scanning is completed, one image is formed by adding the signals while the photoelectric sensor passes through the exposure area EA. This image corresponds to an image formed on the wafer W by the scanning exposure. The state of this image capture will be described with reference to FIG. FIG. 3A shows an output waveform from the photoelectric sensor 3 each time. When the photoelectric sensor 3 is a two-dimensional sensor, the output is represented by a function of XY as position coordinates on the sensor, but only the X component is shown for simplicity of explanation. Here, if the coordinate position of the wafer stage by the laser interferometer 8 when the reference point of the photoelectric sensor 3 is located on the optical axis AX of the projection optical system PL is determined, for example, the coordinate X on the photoelectric sensor 3 can be obtained. , Y can correspond to the position coordinates of the wafer stage, and the image forming position of the mark of the reticle R detected by the photoelectric sensor 3 can also be represented by the position coordinate system of the wafer stage.
[0037]
In FIG. 3A, n is a test mark M of the reticle R. 1 While scanning, the mark M 1 Are shown in the order in which the imaging data is taken. Ideally, no matter when data is acquired while such a mark passes through the illumination area IA, the same projected image should be formed at a certain position in the exposure area EA. A final image should be formed. However, as described above, in order to form an image of a mark on the photoelectric sensor 3 while scanning the reticle R and the photoelectric sensor 3 (wafer W in actual exposure), while the mark passes through the illumination area IA, Mark M 1 The light rays that will form the image of FIG. 3 continuously pass through different portions of the projection optical system PL. Accordingly, distortion occurs in the image due to the presence of aberration in the projection optical system PL, and the image forming position of the mark changes. Further, in the scanning direction, if the reticle stage RST and the wafer stage WST are out of synchronization during one scan, the image forming position of the mark changes. In addition, the positional relationship between the reticle R and the wafer stage WST changes due to the vibration of the entire apparatus due to the scanning, and the imaging position changes.
[0038]
Due to the above-described reason, as shown in FIG. 1 Is shifted in the image forming position. In FIG. 3A, the center position of the image of the mark captured at the second time (n = 2) is shifted by + Δx ′ from the center position of the image of the mark captured at the first time, and n = 1) mark M 1 Is shifted by + Δx ″ from the center position of the first captured image of the mark. The shape of each mark image is also different depending on the light beam passing position of the projection optical system PL or the Z sensor. Due to the following control error with respect to the optimum image plane of the wafer stage WST, or the deterioration of the image due to the deviation of the imaging position while capturing the position screen as described above. Is obtained by adding the output images (n = 1 to m) after the image is captured m times.Because of the above-mentioned effects, the waveforms are duller than those of the respective images. The obtained line width 1 is wider than the signal width of each image.
[0039]
Here, the center position X of the image (FIG. 3B) obtained by combining the individual output images is shown. 0 Is obtained. On the other hand, mark M on reticle R 1 From the position coordinates and the magnification of the projection optical system PL, the mark M 1 Is a position (design value) X at which an image should be formed on the photoelectric sensor 3 01 Can be obtained by calculation. Therefore, ΔX = X 0 -X 01 Are marks M of the reticle R generated by various causes including scanning of the reticle R and the photoelectric sensor 3 (wafer W in actual exposure). 1 (The difference between the design value and the actual exposure position) in the X direction.
[0040]
A method for obtaining the baseline of the wafer alignment system from the one-dimensional or two-dimensional imaging position of each mark of the reticle R obtained as described above will be described. The light emitted from the light source 30 of the alignment system is detected by the photoelectric sensor 3 and the irradiation position is obtained by the coordinate system of the wafer stage WST. Then, the intervals in the X direction and the Y direction between the imaging position of the specific mark obtained by the photoelectric sensor 3 in the coordinate system of the wafer stage WST and the irradiation position of the alignment light source 30 are defined as the baseline of the alignment system. be able to. Alternatively, a reference mark that can be detected by an alignment system (alignment sensor) may be put on the glass plate 1 and a baseline may be defined from the reference mark position and a specific mark position on the reticle R. The value of this baseline is stored, and at the time of actual exposure (overlay exposure), the alignment mark of the wafer W is detected by the wafer alignment system 30 to 35, and the stored value of the baseline is used. Thus, the relative position between the wafer W and the reticle R can be adjusted. By defining the baseline of the alignment system in this way, the position of the wafer W to be overlaid and exposed can be accurately determined based on the mark of the reticle R. In addition, since the base line can be obtained by taking into account the relative displacement between the reticle R and the wafer W generated during scanning, the overlay accuracy in scanning exposure can be improved.
[0041]
Next, a method of obtaining the dynamic imaging characteristics of the projection optical system PL in the scanning exposure from the one-dimensional or two-dimensional image forming positions of the marks of the reticle R obtained as described above will be described. The image processing system 4 outputs a composite image as shown in FIG. 1 ~ M 8 Is sent to the calculator 12. In the arithmetic unit 12, each M 1 ~ M 8 The imaging characteristics are calculated from the output of the composite image for. For example, when obtaining the contrast of an image as an imaging characteristic, the output of each detected mark is sliced at an appropriate slice level as shown in FIG. 3B, and the respective line widths l are obtained and compared. Can be determined. Alternatively, it can be obtained from the rising angles of the edges at both ends of the output waveform of each mark.
[0042]
The following method can be used to determine the image magnification as the imaging characteristic. A plurality of marks on the reticle R, for example, a mark M 1 And M 5 Imaging position X 1 And X 5 Are detected in the X coordinate system of the photoelectric sensor 3 and are converted from the image forming positions into the X coordinate system of the wafer stage WST. 1 And X 5 And mark M on reticle R 1 And M 5 Can be calculated from the interval in the X direction.
[0043]
In addition, the following method can be employed to obtain distortion as the imaging characteristic. For example, a set A of two points relatively inside and relatively outside the pattern area 40 of the reticle R 1 , A 2 And B 1 , B 2 Is their spacing A 1 A 2 And interval B 1 B 2 Are determined so as to be equal to each other, and their imaging positions are detected by the photoelectric sensor 3 in the same manner as described above, and the imaging positions are obtained in the coordinate system of the wafer stage WST. Next, the image forming position interval A of the set of two points in the coordinate system of wafer stage WST 1 A 2 'And spacing B 1 B 2 'Respectively, and the difference from the interval on the reticle R (A 1 A 2 '-A 1 , A 2 ) And (B) 1 B 2 '-B 1 , B 2 ) Can be calculated, and the distortion can be obtained by comparing them in consideration of the magnification.
[0044]
Further, from the measurement of the image forming position of the mark of the reticle R as described above, the amount of rotation of the reticle R on the reticle stage RST caused by the scanning of the reticle R can be obtained. In this case, of the marks of the reticle R, for example, the mark M 1 And M 5 Image formation position Y in the Y direction on photoelectric sensor 3 1 And Y 5 Is detected in the same manner as described above. Imaging position Y 1 And Y 5 Coordinate Y of wafer stage WST corresponding to 1 'And Y 5 By obtaining the difference ΔY ′, it is possible to determine how much the pattern of the reticle R is shifted in the Y direction. Further, ΔY ′ and M 1 And M 5 The rotation amount θ of the reticle R can be calculated from the distance in the X direction and the like.
[0045]
Further, the displacement of the entire pattern of the reticle R can be obtained as follows. For example, reticle R is arranged on reticle stage RST such that the center of reticle R is located on the optical axis of projection optical system PL, and two-dimensional imaging of each mark by photoelectric sensor 3 as described above. Find the position. Next, after converting the image forming position of each mark into the wafer stage coordinate system, the distance between the reference point (wafer stage coordinate system) on the sensor 3 and the image forming position of each mark (wafer stage coordinate system) is obtained. . Then, those distances and each mark M of the reticle R from the center of the reticle R 1 ~ M 8 Distance L 1 ~ L 8 Is compared in consideration of the magnification, the offset amount of the pattern of the reticle R in the scanning of the reticle R can be determined. In this case, the offset amount of the pattern of the reticle R can be obtained by comparing the distance from the center of the reticle R with the distance between the image forming position and the reference point for one mark. Mark M 1 ~ M 8 It is preferable to calculate the offset amount from the average value by calculating the difference between the distances.
[0046]
As described above, the imaging characteristics of the image formed by the scanning exposure can be obtained. When the imaging characteristics cannot be obtained with the desired accuracy, correction may be performed. However, as a premise, since the imaging characteristics (image characteristics of a still image) measured when the stage is stationary are adjusted optimally, further adjustment is difficult. As an adjustment method at this stage, it is conceivable to reduce synchronization deviation, vibration, and the like of the reticle R and the wafer W, which are deteriorated by the scanning exposure. In general, when the scanning speed is reduced, the load on the control system is reduced, and the synchronization accuracy is improved. It is also believed that vibrations are reduced. Therefore, when the desired accuracy is not achieved due to the positional deviation of the image forming position of the mark obtained as described above, a method of sending a signal to the stage controller 14 to reduce the scanning speed is conceivable. When the scanning speed is reduced, the productivity (throughput) of the product is reduced. Therefore, it is optimal to reduce the scanning speed within a range where desired accuracy can be obtained. Therefore, the optimum speed can be selected by changing the scanning speed and measuring the imaging characteristics. Since the scanning speed is determined by the sensitivity of the photosensitive agent as described above, it is necessary to take measures such as adjusting the illuminance of the illumination light according to the speed or changing the width of the illumination area IA in the scanning direction.
[0047]
In the above-described method, image data is added one after another inside the image processing system 4. However, a method of temporarily storing all data in a memory and then adding the data to combine the images may be considered. According to this method, since each data remains in the memory even after the synthesis, when the accuracy is not good, there is an advantage that it is possible to analyze which part of the exposure area EA is not good. In the above-described method, the image data is added by calculation, but a method of adding the image data in the photoelectric sensor 3 is also conceivable. By reducing the intensity of the illumination light with a filter or the like so that an image is accumulated in the sensor 3 in one scan, a total photoelectric output during one scan can be obtained. This method simplifies the circuit configuration because there is no need for calculation.
[0048]
Further, in the above-described method, the addition is performed with reference to the pixels of the photoelectric sensor 3, but a measurement error occurs when the positional relationship between the reticle stage RST and the photoelectric sensor 3 changes due to vibration of the apparatus or the like. For this reason, if the index or the frame is attached to the glass plate 1 and the addition is performed so that the detection position of the index or the frame detected by the photoelectric sensor 3 becomes constant, the above-mentioned inconvenience is eliminated. It is convenient if this index is common to the reference mark detected by the alignment sensor at the time of the baseline measurement.
[0049]
When the focal position is obtained by the above method, it is a common practice to repeat the measurement while changing the position of wafer stage WST in the Z direction, but light can be received at a plurality of positions in the optical axis direction of magnifying optical system 2. As described above, a method in which light is branched by a half mirror or the like and received by a plurality of photoelectric sensors is also conceivable. Further, a method is also conceivable in which a plurality of photoelectric sensors 3 and a magnifying optical system 2 are arranged on the wafer stage WST and measurement is performed at a plurality of measurement points in the exposure area EA at once. According to this method, there is an advantage that a plurality of points can be measured by one scan. Further, if the distance between the photoelectric sensors in the non-scanning direction is strictly measured in advance, there is an advantage that the measurement accuracy of the distortion in the non-scanning direction can be measured accurately regardless of the measurement error of the interferometer 9.
[0050]
In the method of the embodiment described above, the photoelectric sensor 3 is provided inside the wafer stage WST. Only the incident end face of the fiber) may be installed on the wafer stage WST, and the received light may be transmitted to an optical sensor installed outside the wafer stage WST using an image fiber or the like. It is also possible to guide the illumination light to wafer stage WST with a fiber or the like, emit a test pattern from wafer stage WST, and receive the test pattern with a photoelectric sensor on reticle stage RST.
[0051]
The present invention is possible when using a photoelectric sensor having either two-dimensional or one-dimensional resolution as described above. Normally, contrast, distortion, and the like are measured by a plurality of lines (lines and spaces) in the XY directions or a single line (isolated lines). Therefore, in the case of a one-dimensional sensor, sensors are arranged in two directions of the X direction and the Y direction. The two-dimensional sensor can be arranged so as to have a resolution in the X and Y directions, and by selecting data, data processing of the X and Y components can be performed.
[0052]
Although the projection exposure apparatus of the above embodiment uses the projection optical system PL for semiconductor manufacturing, the present invention uses a scanning exposure apparatus other than the scanning exposure apparatus using the projection optical system, for example, a mirror optical system. This is similarly effective for a scanning type exposure apparatus that performs the above.
[0053]
【The invention's effect】
The scanning exposure apparatus according to the present invention measures and adjusts dynamic conditions of scanning exposure, that is, information and image forming characteristics relating to an image position while the mask stage and the substrate stage are moving, before actual exposure. Since a mechanism capable of performing calculations is provided, it is possible to know in advance, for example, an image position shift and an error in an image forming characteristic caused by a cause unique to the scanning exposure apparatus, thereby correcting the image forming characteristic. Exposure conditions can be changed as described above. Since the scanning exposure method of the present invention measures and calculates information and image forming characteristics of the image position under dynamic conditions of the scanning exposure before the actual exposure, it is unique to the scanning exposure method. It is possible to know in advance the displacement of the image position, the error in the imaging characteristics, and the like caused by the cause, so that the exposure conditions can be changed so as to correct the imaging characteristics. Further, by correcting in advance information and image forming characteristics relating to the image position measured under static conditions based on the positional deviation and image forming characteristics measured under the above dynamic conditions, the image forming characteristics at the time of scanning exposure are improved. Can be determined more accurately in advance. Therefore, by using the scanning exposure apparatus and the scanning exposure method of the present invention, microdevices such as semiconductor elements and liquid crystal elements can be manufactured with higher accuracy and higher efficiency.
[Brief description of the drawings]
FIG. 1 shows an outline of a configuration of a scanning exposure apparatus of the present invention including a mechanism capable of measuring an imaging characteristic during scanning in advance.
2A and 2B are views for explaining a scanning exposure method by the scanning exposure apparatus of the embodiment, and FIG. 2A shows a state in which a reticle R scans an illumination area IA; (B) FIG. 4 is a diagram showing a state in which the wafer W is scanned in a direction opposite to the scanning direction of the reticle R with respect to the exposure area EA.
3A and 3B are diagrams showing detection images of test marks on a reticle R taken into a photoelectric sensor during scanning in the embodiment, and FIG. Statue FIG. 3B shows a composite image obtained by adding each image signal when the image data has been captured m times.
FIG. 4 shows a test mark M used in the embodiment. 1 ~ M 8 FIG. 4 is a plan view of a reticle including a reticle.
FIG. 5 is a diagram illustrating an outline of a configuration of a conventional projection exposure apparatus including a measurement system of an imaging characteristic.
[Explanation of symbols]
R reticle,
W wafer
PL projection optical system
IA lighting area
EA exposure area
RST reticle stage
WST wafer stage
1 glass plate
2 Magnifying optical system
3 Photoelectric sensor
4 Image processing system
5 Wafer holder
7 Laser interferometer
10 Floodlight
12 arithmetic unit
14 Stage Controller
30 Alignment light source

Claims (13)

  1. A mask stage that scans the mask with respect to an illumination area on the mask, a projection optical system that projects an image of a pattern on the mask onto a photosensitive substrate, and an exposure area that is conjugate with respect to the illumination area and the projection optical system. In a scanning exposure apparatus having a substrate stage for scanning the photosensitive substrate,
    A photoelectric detection unit comprising a light receiving unit on the substrate stage and photoelectrically detecting an image of a mark pattern on the mask,
    Synthesizing means for synthesizing a signal output from the photoelectric detection means while scanning the light receiving section with respect to the exposure area in synchronization with scanning of the mark pattern with respect to the illumination area. ,
    The scanning exposure apparatus according to claim 1, wherein a position or a displacement of the image of the mark pattern is detected based on an output of the combining unit.
  2. An alignment system that illuminates the alignment mark on the photosensitive substrate, receives reflected light from the alignment mark, and detects the position, or the position shift, of the position of the detected mark pattern image; 2. The scanning exposure apparatus according to claim 1, wherein a difference from a light irradiation position of the system is set as a baseline of the alignment system.
  3. Detecting means for detecting at least one of the position and the amount of rotation of the pattern image of the mask based on the position or displacement of each image of the plurality of mark patterns on the mask, and utilizing a detection result of the detecting means The scanning exposure apparatus according to claim 1, wherein the mask is aligned with the photosensitive substrate.
  4. 4. The image processing apparatus according to claim 1, further comprising an arithmetic unit configured to calculate an imaging characteristic of the projection optical system based on a position or a position shift of each image of the plurality of mark patterns on the mask. 5. A scanning exposure apparatus according to claim 1.
  5. A mask stage that scans the mask with respect to an illumination area on the mask, a projection optical system that projects an image of a pattern on the mask onto a photosensitive substrate, and an exposure area that is conjugate with respect to the illumination area and the projection optical system. In a scanning exposure apparatus having a substrate stage for scanning the photosensitive substrate,
    A light-receiving unit disposed on the substrate stage, and photoelectric detection means for photoelectrically detecting an image of a mark pattern on the mask;
    Synthesizing means for synthesizing a signal output from the photoelectric detection means while scanning the light receiving unit with respect to the exposure area in synchronization with scanning of the mark pattern with respect to the illumination area;
    Calculating means for calculating an image formation state of the image of the mark pattern based on an output of the synthesizing means.
  6. The scanning exposure apparatus according to claim 4, further comprising a correction unit configured to correct an imaging characteristic of the projection optical system according to a calculation result of the calculation unit.
  7. The scanning exposure apparatus according to claim 6, wherein the correction unit is a stage controller that controls a scanning speed or a scanning direction of the mask stage and the substrate stage.
  8. The photoelectric detection unit includes an image sensor having a light receiving surface disposed on a surface substantially conjugate with the light receiving unit, and an enlargement optical system that enlarges the image of the mark pattern to form an image on the light receiving surface. The scanning exposure apparatus according to claim 1, wherein:
  9. A method for manufacturing a micro device using the scanning exposure apparatus.
  10. While illuminating the mask, the mask is scanned with respect to an illumination area on the mask, and a photosensitive substrate is scanned in synchronization with the scanning of the mask with respect to an exposure area conjugate with the illumination area and the projection optical system. In the scanning exposure method of exposing the pattern of the mask on the photosensitive substrate through the projection optical system by the
    Prior to the exposure, in place of the photosensitive substrate, a light receiving unit of a detecting unit that detects an image of a mark pattern formed on the mask is scanned in synchronization with the scanning of the mask,
    The scanning type exposure method according to claim 1, wherein a signal or a displacement of a mark pattern image of a mask during the scanning is obtained by combining signals output from the detection means during the scanning.
  11. While illuminating the mask mark pattern in a state where the mask is fixed to the illumination area, the image of the mark pattern in the exposure area is detected, and information on the image position of the detected mark pattern is obtained. 11. The scanning exposure method according to claim 10, further comprising correcting the position of the mark pattern image of the mask during the scanning or the positional deviation.
  12. The scanning exposure method according to claim 11, further comprising calculating an imaging characteristic of the projection optical system from information on an image position of the corrected mark pattern.
  13. While illuminating the mask, the mask is scanned with respect to an illumination area on the mask, and a photosensitive substrate is scanned in synchronization with the scanning of the mask with respect to an exposure area conjugate with the illumination area and the projection optical system. In the scanning exposure method of exposing the pattern of the mask on the photosensitive substrate through the projection optical system by the
    Prior to the exposure, in place of the photosensitive substrate, a light receiving unit of a detecting unit that detects an image of a mark pattern formed on the mask is scanned in synchronization with the scanning of the mask,
    During the scanning, the signals output from the detection unit are combined to obtain a mark pattern image of the mask during the scanning,
    The scanning type exposure method according to claim 1, wherein an image forming characteristic of the projection optical system is calculated from the obtained mark pattern image.
JP22481395A 1995-08-09 1995-08-09 Scanning exposure apparatus and exposure method Expired - Fee Related JP3551570B2 (en)

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JP22481395A JP3551570B2 (en) 1995-08-09 1995-08-09 Scanning exposure apparatus and exposure method
US08/691,377 US5841520A (en) 1995-08-09 1996-08-02 Exposure apparatus and method that use mark patterns to determine image formation characteristics of the apparatus prior to exposure
KR1019960033727A KR970012020A (en) 1995-08-09 1996-08-09 A scanning type exposure apparatus, a scanning type exposure method, and a projection exposure apparatus

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JP2002139847A (en) * 2000-10-31 2002-05-17 Nikon Corp Aligner, exposing method and device manufacturing method
KR101769722B1 (en) * 2003-08-21 2017-08-18 가부시키가이샤 니콘 Exposure apparatus, exposure method, and device producing method
US7126668B2 (en) * 2004-04-28 2006-10-24 Litel Instruments Apparatus and process for determination of dynamic scan field curvature
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