JP2006226719A - Surface shape measuring method, attitude measuring method, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface shape measuring method or the like capable of improving position detection accuracy of a stage, even if distortion is generated in the stage itself as a moving body. <P>SOLUTION: An inclination, to the Z-axis, of a moving mirror 12 provided on a wafer stage WST is measured by using a laser interferometer 13, and the attitude of the wafer stage WST is controlled so that the inclination of the moving mirror 12 to the Z-axis becomes zero, based on a measurement result, and the attitude of the wafer stage WST at that time is measured by using a multipoint focus position detection system 21. This processing is repeated, while the wafer stage WST is moved finely along the mirror surface of the moving mirror 12 which is a measuring object. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface shape measuring method for measuring the shape of a reflecting surface provided on a moving body, a posture measuring method for measuring the posture of a moving body with respect to a reference plane using a measurement result of the method, and an exposure method.

  Conventionally, in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, and other devices, a pattern formed on a mask or a reticle (hereinafter referred to as a mask when these are collectively referred to) is passed through a projection optical system. 2. Description of the Related Art Exposure apparatuses that transfer onto a substrate such as a wafer or a glass plate coated with a resist or the like are used. As the exposure apparatus, a stationary exposure type projection exposure apparatus such as a so-called stepper and a scanning exposure type projection exposure apparatus such as a so-called scanning stepper are mainly used. In these projection exposure apparatuses, since it is necessary to sequentially transfer the pattern formed on the mask to a plurality of shot areas on the substrate, a substrate stage capable of two-dimensional movement while holding the substrate is provided. In the case of the above-described scanning exposure type projection exposure apparatus, the mask stage holding the mask is also movable in the scanning direction.

  In such a projection exposure apparatus, since a circuit pattern having an extremely fine structure is transferred to a substrate, position control between the substrate and the mask needs to be performed with high accuracy. For this reason, the length measurement beam from the laser interferometer is irradiated to the reflecting mirrors provided on the substrate stage and the mask stage, and each of the reflection mirrors and the reference light is based on the fringe pattern or phase difference of the interference light. The position information of the stage is detected with high accuracy, and based on the detection result, the position control of each stage is performed with high accuracy.

  By the way, in such position detection of the substrate stage and the mask stage, if the mirror surface of the reflecting mirror provided on each stage has waviness or twist, an error occurs in the detection value by the laser interferometer, and the detection accuracy is lowered. There is a risk of inviting. For this reason, the surface shape (two-dimensional shape) of the mirror surface of the reflecting mirror is measured, and the detection result of the laser interferometer is corrected based on the measurement result. As a technique for measuring the surface shape of the mirror surface of the reflecting mirror, for example, a technique described in Patent Document 1 below by the applicant of the present application is known.

  In this technique, the two-dimensional shape along the longitudinal direction of the reflecting mirror at each of two locations in the short direction (height direction) of the reflecting mirror (hereinafter sometimes referred to as an upper stage or a lower stage) is based on an appropriate standard. The surface shape of the mirror surface of the reflector is specified by obtaining the relative relationship between the measured value at the upper stage and the measured value at the lower stage (here, the offset in the direction orthogonal to the reflecting surface) as follows: I have to.

That is, the measurement substrate on which a plurality of reference marks arranged in a predetermined relationship are formed is placed on the substrate stage so that the arrangement direction of the reference marks and the axial direction of the substrate stage exactly coincide with each other. Before or after each of the upper one-dimensional shape measurement and the lower one-dimensional shape measurement, the position of the reference mark on the measurement substrate is measured by an off-axis type alignment sensor. The offset is calculated.
International Publication No. 00/22376 Brochure

  By the way, when the temperature changes or the atmospheric pressure changes, the stage to which the reflecting mirror is attached may be distorted. If the mirror surface of the reflecting mirror provided on the stage has waviness or twist, an error occurs in the detection value by the laser interferometer as described above, but even if the stage itself is distorted, the mirror surface of the reflecting mirror has waviness or the like. Detection errors occur as in some cases. For example, if the mirror falls down due to distortion of the stage that occurs at the end where the reflector is attached, the stage itself is tilted even though the center of the stage where the substrate or wafer is held is horizontal. Are erroneously detected by the laser interferometer. As a result, the posture of the stage is erroneously controlled to correct the erroneously detected stage tilt.

  In the conventional technique described above, the surface shape itself along the longitudinal direction of the reflecting mirror can be measured, but it cannot be determined whether or not it is based on the distortion of the stage. For this reason, when trying to correct the detection result of the laser interferometer by measuring the surface shape of the reflecting mirror by the method described above, a situation may occur in which correction is excessive or insufficient.

  The present invention has been made in view of the above circumstances, and uses a surface shape measurement method capable of improving the position detection accuracy of a stage even when the stage itself as a moving body is distorted, and a measurement result of the method. It is an object of the present invention to provide an attitude measurement method capable of measuring the attitude of a stage with respect to a reference plane with high accuracy, and an exposure method for performing an exposure process while moving the stage based on the measurement result of the method.

The present invention adopts the following configuration corresponding to each diagram shown in the embodiment. However, the reference numerals with parentheses attached to each element are merely examples of the element and do not limit each element.
In order to solve the above problems, a surface shape measuring method according to a first aspect of the present invention is provided in a moving body (WST) that moves along a reference plane (7) orthogonal to a first axis (Z axis). A surface shape measuring method for measuring a shape of a reflecting surface (12, 12X, 12Y) extending along a second axis (X axis or Y axis) direction orthogonal to the first axis direction, wherein the first axis A first step (S13, S33) for measuring the tilt of the reflecting surface with respect to the angle, and a posture of the moving body so that the tilt of the reflecting surface with respect to the first axis becomes zero based on the measurement result of the first step. A second step (S14, S34) for controlling the movement, a third step (S15, S35-S38) for measuring the posture of the moving body with respect to the reference plane, and moving the moving body along the second axis direction. From the first step The fourth step of repeating three steps (S16, S17, S39, S40) is characterized in that it comprises a.
According to this invention, first, the inclination of the reflecting surface with respect to the first axis is measured, and then the posture of the moving body is controlled so that this inclination becomes zero, and then the posture of the moving body at this time is measured. The above processing is performed while moving the moving body along the length direction of the reflecting surface (second axis direction orthogonal to the first axis direction).
In order to solve the above problems, a surface shape measuring method according to a second aspect of the present invention is provided in a moving body (WST) that moves along a reference plane (7) orthogonal to a first axis (Z axis). A surface shape measuring method for measuring the shape of a reflecting surface (12, 12X, 12Y) extending along a second axis direction (X axis or Y axis) orthogonal to the first axis direction, the method being for the reference plane A first step (S23) for measuring the posture of the moving body; a second step (S24) for controlling the posture of the moving body to a predetermined posture based on the measurement result of the first step; From the first step while measuring the inclination of the reflecting surface with respect to the first axis in a state controlled to the predetermined posture (S25), and moving the movable body along the second axis direction. The fourth step to repeat the third step Tsu is characterized in that it comprises a-flops (S26, S27).
According to this invention, first, the attitude of the moving body with respect to the reference plane is measured, and then the attitude of the moving body is controlled to a predetermined attitude based on the measurement result, and then the inclination of the reflecting surface with respect to the first axis is then controlled in this state. measure. The above processing is performed while moving the moving body along the length direction of the reflecting surface (second axis direction orthogonal to the first axis direction).
In order to solve the above-described problem, the posture measuring method of the present invention is a reflective surface (12, 12X, 12Y) extending along a second axis (X axis or Y axis) direction orthogonal to the first axis direction (Z axis). The position of the movable body (WST) that moves along the reference plane (7) orthogonal to the first axis with respect to the reference plane is separated by two positions in the first axis direction of the reflecting surface A posture measurement method for measuring with a measurement beam (DL) simultaneously irradiated to the surface, the step of measuring the surface shape of the reflection surface by any one of the surface shape measurement methods described above, Simultaneously irradiating a measurement beam to receive each reflected light from the reflecting surface, and measuring the inclination of the reflecting surface with respect to the first axis from the received light result, based on the measurement result of the surface shape, The measurement result of the tilt of the reflecting surface Correct, is characterized by comprising the steps of obtaining a posture of the moving body with respect to the reference plane.
According to this invention, first, the surface shape of the reflecting surface is measured, and the inclination of the reflecting surface measured by irradiating the reflecting surface with the measurement beam is corrected based on the surface shape measurement result, and the posture of the moving body with respect to the reference plane is corrected. Is obtained.
Furthermore, the exposure method of the present invention comprises a mask (R) on a photosensitive object (W) held by a movable body (WST) movable along a reference plane (7) orthogonal to the first axis (Z axis). In the exposure method for transferring the pattern, the movement of the moving body is controlled based on the measurement result of the posture measurement method.
According to this invention, the movement of the moving body is controlled based on the measurement result in which the tilt of the reflecting surface is corrected during exposure.

According to the present invention, there is an effect that the position detection accuracy of the stage can be improved even when the stage itself as the moving body is distorted.
In addition, since the posture of the moving body is obtained by correcting the tilt of the reflecting surface irradiated with the measurement beam based on the surface shape measurement result of the reflecting surface, the posture of the stage relative to the reference plane can be measured with high accuracy. There is an effect that can be done.
Furthermore, according to the present invention, since the movement of the moving body is controlled based on the measurement result in which the tilt of the reflecting surface is corrected during exposure, the exposure accuracy (resolution, transfer fidelity, overlay accuracy, etc.) is improved. There is an effect that can be.

  Hereinafter, a surface shape measurement method, a posture measurement method, and an exposure method according to an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a view showing a schematic configuration of an exposure apparatus in which a surface shape measuring method, an attitude measuring method, and an exposure method according to the first embodiment of the present invention are used. An exposure apparatus EX shown in FIG. 1 is an exposure apparatus for manufacturing a semiconductor element. A pattern formed on a reticle R is sequentially transferred while a reticle R as a mask and a wafer W as a photosensitive object are moved synchronously. This is a reduction projection type exposure apparatus of a step-and-scan method for transferring onto W.

  In the following description, if necessary, an XYZ orthogonal coordinate system is set in the drawing, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. This XYZ orthogonal coordinate system is set so that the X-axis and the Z-axis are parallel to the paper surface, and the Y-axis is set to a direction perpendicular to the paper surface. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z-axis is set vertically upward. Further, it is assumed that the synchronous movement direction (scanning direction) of reticle R and wafer W during exposure is set in the Y direction.

  An exposure apparatus EX shown in FIG. 1 holds an illumination optical system (not shown) that illuminates a slit-shaped (rectangular or arc-shaped) illumination area on a reticle R with exposure light EL having uniform illuminance, and the reticle R. Reticle stage RST, projection optical system PL for projecting an image of the pattern of reticle R onto wafer W coated with photoresist, wafer stage WST as a moving body for holding wafer W, and a control system thereof It is configured to include.

The illumination optical system (not shown) includes a light source unit, an illumination uniformizing optical system including an optical integrator, a beam splitter, a condensing lens system, a reticle blind, an imaging lens system, and the like (all not shown). It is configured. The configuration of the illumination optical system is disclosed in, for example, JP-A-9-320956. Here, as the light source unit, a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ laser light source (wavelength 157 nm), a Kr ₂ laser light source (wavelength 146 nm), an Ar ₂ laser light source ( An ultraviolet laser light source having a wavelength of 126 nm), a copper vapor laser light source, a harmonic generation light source of a YAG laser, a harmonic generation device of a solid-state laser (semiconductor laser, etc.), or a mercury lamp (i-line, etc.) can also be used. .

  The reticle stage RST is a reticle scanning stage 2 that can move with a predetermined stroke in the scanning direction (Y direction) on the upper surface of a reticle support base (surface plate) 1 disposed horizontally below the illumination optical system (−Z direction). And a reticle fine movement stage 3 mounted on the reticle scanning stage 2 and capable of being finely driven in the X direction, the Y direction, and the rotation direction around the Z axis (θZ direction) with respect to the reticle scanning stage 2. ing. The reticle R is held on the reticle fine movement stage 3 by vacuum suction or electrostatic suction.

  A movable mirror 4 is provided at one end of the reticle micro-driving stage 3, and a laser interferometer (hereinafter referred to as a reticle interferometer) 5 is disposed on the reticle support base 1. The laser light emitted from the reticle interferometer 5 is irradiated onto the mirror surface of the movable mirror 4, and the reticle interferometer 5 receives the interference light between the reflected light and the reference light, so that the X direction of the reticle micro-drive stage 3, Positions in the Y direction and the rotational direction around the Z axis (θZ direction) are detected. On the actual reticle fine movement stage 3, an X-axis reflecting mirror and two Y-axis reflecting mirrors are fixed, and a plurality of reticle interferometers 5 are provided correspondingly, but in FIG. These are representatively shown as a reflecting mirror 4 and a reticle interferometer 5. The reticle stage RST may be configured to drive a movable body in which a reticle table fine movement mechanism (actuator such as a voice coil motor) holding the reticle R is one-dimensionally driven in the scanning direction (Y direction) with a linear motor, for example. Good. Further, the end surface of reticle fine movement stage 3 (or reticle table) may be mirror-finished and used instead of the mirror surface of fixed mirror 4 described above.

  Position information (or velocity information) of reticle fine movement stage 3 detected by reticle interferometer 5 described above is supplied to main control system 20 that controls the overall operation of the apparatus. The main control system 20 controls operations of the reticle scanning stage 2 and the reticle fine movement stage 3 via a reticle driving device 6 including a linear motor for driving the reticle scanning stage 2 and a voice coil motor for driving the reticle fine movement stage 3. .

  The projection optical system PL described above includes a plurality of refractive optical elements (lens elements), and both the object plane (reticle R) side and the image plane (wafer W) side are telecentric and have a predetermined reduction magnification β (β For example, 1/4 or 1/5) is used. The direction of the optical axis AX of the projection optical system PL is a Z direction orthogonal to the XY plane. For example, quartz or fluorite is used as the glass material of the plurality of lens elements provided in the projection optical system PL according to the wavelength of the exposure light EL. In the present embodiment, the projection optical system PL that projects an inverted image of the pattern formed on the reticle R onto the wafer W will be described as an example. Of course, even if an upright image of the pattern is projected. good.

  Wafer stage WST is arranged below projection optical system PL (−Z direction), and includes wafer XY drive stage 8, fulcrums 9 a to 9 b, wafer table 10, and wafer holder 11. The wafer XY drive stage 8 is configured to be movable in the X direction and the Y direction on the upper surface (reference plane) of the wafer support base (surface plate) 7, and is extendable in the Z direction on the wafer XY drive stage 8. Three fulcrum points 9a to 9c are provided. The wafer table 10 is placed on the fulcrums 9a to 9b, and fine movement in the Z direction (including rotation about the X axis and rotation about the Y axis) is possible by controlling the amount of expansion and contraction of the fulcrums 9a to 9b. It is. A wafer W is held on a wafer holder 11 provided on the wafer table 10 by vacuum chucking or electrostatic chucking. The upper surface of the wafer holder 11 becomes the object placement surface.

  A movable mirror 12 is provided at one end on the wafer table 10, and a laser interferometer (hereinafter referred to as a wafer interferometer) that irradiates the mirror surface (reflecting surface) of the movable mirror 12 with laser light outside the wafer stage WST. 13 is provided. The wafer interferometer 13 receives the interference light between the reflected light and the reference light obtained by irradiating the mirror surface of the movable mirror 12 with the laser light, and thereby the position and orientation of the wafer table 10 in the X direction and the Y direction. (Rotation around the X, Y, and Z axes) is detected. Next, a more detailed configuration of wafer stage WST and wafer interferometer 13 will be described.

  FIG. 2 is a perspective view showing the configuration of wafer stage WST and wafer interferometer 13. As shown in FIG. 2, the three fulcrums 9 a to 9 c that support the wafer table 10 are arranged so as to form an angle of 120 ° with respect to the center of the wafer wafer table 10, for example. The displacements of these fulcrums 9a to 9c are detected by encoders Ea to Ec associated therewith. The fulcrums 9a to 9c are configured by using, for example, a method using a rotary motor and a cam, a laminated piezoelectric element (piezo element), a voice coil motor (herein referred to as a voice coil motor), or the like. The encoders Ea to Ec are disposed in the vicinity of the fulcrums 9a to 9c, and optical or electrostatic linear encoders can be used as the encoders Ea to Ec. The sensors Ea to Ec for detecting the displacements (drive amounts) of the fulcrums 9a to 9c are not limited to encoders, and may be arbitrary.

  The three fulcrums 9 a to 9 c are controlled by the main control system 22. By uniformly expanding and contracting the fulcrums 9a to 9c, the position (focal position) of the wafer table 10 in the Z direction can be adjusted, and by individually adjusting the expansion and contraction amounts of the three fulcrums 9a to 9c, the wafer can be adjusted. The inclination angle of the table 10 around the X axis and the Y axis can be adjusted. Detection values (displacements) in the Z-axis direction obtained from the three encoders Ea to Ec are supplied to the main control system 20. The main control system 20 determines the position of the wafer W in the Z-axis direction, the tilt angle around the X-axis, based on the detection values of the encoders Ea to Ec and the arrangement of the encoders Ea to Ec (positional relationship in the XY plane). The inclination angle around the Y axis is obtained.

  As shown in FIG. 2, the movable mirror 12 simplified in FIG. 1 includes an X-axis movable mirror 12X having a mirror surface that intersects the X axis and extends along the Y direction, and an X axis that intersects the Y axis. And a Y-axis movable mirror 12Y having a mirror surface extending in the direction. Further, as shown in FIG. 2, the wafer interferometer 13 simplified in FIG. 1 emits laser light to the wafer interferometers 13X and 13XP that irradiate the movable mirror 12X with laser light and the movable mirror 12Y. It includes a wafer interferometer 13Y and 13YP to be irradiated.

  The wafer interferometer 13X irradiates two portions of the mirror surface of the movable mirror 12X with the same position in the Z direction but different positions in the Y direction, receives the reflected light from the movable mirror 12X, and receives the wafer. The position of the table 10 in the X direction and the rotation amount (yawing amount) of the wafer table 10 around the Z axis are detected. Also, the wafer interferometer 13XP irradiates two places with the same position in the Y direction but different positions in the Z direction with respect to the mirror surface of the moving mirror 12X, and receives the reflected light from the moving mirror 12X. Then, the rotation amount (rolling amount) of the wafer table 10 around the Y axis is detected.

  Similarly, the wafer interferometer 13Y irradiates two places with the same position in the Z direction but different positions in the X direction with respect to the mirror surface of the movable mirror 12Y, and receives the reflected light from the movable mirror 12Y. Then, the position of the wafer table 10 in the Y direction and the rotation amount (yawing amount) of the wafer table 10 around the Z axis are detected. Further, the wafer interferometer 13YP irradiates two places with the same position in the X direction but different positions in the Z direction with respect to the mirror surface of the moving mirror 12Y, and receives the reflected light from the moving mirror 12Y. Then, the rotation amount (pitching amount) around the X axis of the wafer table 10 (wafer stage WST) is detected. The detection results of the wafer interferometers 13X, 13XP, 13Y, and 13YP are supplied to the main control system 20.

  The main control system 20 controls the position and posture of the wafer table 10 via the wafer driving device 14 shown in FIG. 1 based on the detection results of the wafer interferometers 13X, 13XP, 13Y, and 13YP, and controls the operation of the entire device. Control. Further, in order to take correspondence between the wafer coordinate system defined by the coordinates obtained from the detection result of the wafer interferometer 13 and the reticle coordinate system defined by the coordinates obtained from the detection result of the reticle interferometer 5 on the reticle R side. In addition, as shown in FIG. 1, a reference mark plate 15 is fixed on the wafer table 10 in the vicinity of the wafer holder 11. Various reference marks are formed on the reference mark plate 15. Among these reference marks, there is also provided a reference mark that is illuminated from the back side by illumination light guided into the wafer table 10, that is, a luminescent reference mark.

  The exposure apparatus EX of the present embodiment is disposed above the reticle R, and reticle alignment for simultaneously observing the reference mark on the reference mark plate 15 and the alignment mark (reticle alignment mark) formed on the reticle R. Sensors 16a and 16b are provided. Observation results (measurement results) of these reticle alignment sensors 16 a and 16 b are supplied to the main control system 20. In the reticle alignment sensors 16a and 16b, deflection mirrors 17a and 17b for guiding the detection light from the reticle R to each of them are movably arranged. When the exposure sequence is started, these deflecting mirrors 17a and 17b are retracted by the mirror driving devices 18a and 18b, respectively, under a command from the main control system 20.

  An image processing type off-axis alignment sensor for observing an alignment mark (wafer alignment mark) attached to a shot area set on the wafer W on the side surface in the Y direction of the projection optical system PL 19 (hereinafter referred to as a wafer alignment sensor) is arranged. The observation result (measurement result) of the wafer alignment sensor 19 is supplied to the main control system 20. The optical axis of the optical system of the wafer alignment sensor 19 is parallel to the optical axis AX of the projection optical system PL. The detailed configuration of the alignment sensor 19 is disclosed in, for example, Japanese Patent Laid-Open No. 9-219354 and US Pat. No. 5,859,707 corresponding thereto.

  Furthermore, the exposure apparatus EX of the present embodiment includes a light transmission system 21a and a light reception system 21b, and is set in and near the exposure area on the wafer W conjugate with the illumination area on the reticle R with respect to the projection optical system PL. A multi-point focus position detection system 21 that detects the position in the Z direction (optical axis AX direction) of the surface of the wafer W at each of the plurality of detection points is provided on the side of the projection optical system PL. The multipoint focus position detection system 21 detects the position and posture (leveling) in the Z direction on the surface of the wafer W. FIG. 3 is a diagram showing the configuration of the oblique incidence type multipoint focus position detection system 21. In the oblique incidence type multi-point focus position detection system 21 shown in FIG. 3, illumination light having a wavelength range that does not sensitize the photoresist on the wafer W is different from the wavelength range of the exposure light EL. From the optical fiber bundle 22.

  The illumination light emitted from the optical fiber bundle 22 illuminates the pattern forming plate 24 through the condenser lens 23. FIG. 4 is a cross-sectional view illustrating a configuration example of the pattern forming plate 24. As shown in FIG. 4, nine slit-shaped opening patterns 34-11 to 34-19 are formed in the first row on the pattern forming plate 24, and 9 in the second row to the fifth row, respectively. Opening patterns 34-21 to 34-29, 34-31 to 34-39, 34-41 to 34-49, 34-51 to 34-59 are formed. That is, a total of 45 slit-shaped opening patterns are formed on the pattern forming plate 24, and images of these slit-shaped opening patterns are formed on the surface of the wafer W in FIG. Projected diagonally.

  The illumination light transmitted through the pattern forming plate 24 is projected onto the surface of the wafer W through the lens 25, the mirror 26, and the irradiation objective lens 27, and an image of the pattern on the pattern forming plate 24 is projected onto the surface of the wafer W. The projection image is formed obliquely with respect to the optical axis AX of the system PL. FIG. 5 is a view showing a projected image of the opening pattern projected onto a plurality of detection points set in and near the exposure area on the wafer W. FIG. In FIG. 5, the rectangular area to which the symbol EF is attached represents the exposure area described above. An image of the pattern of the reticle R is projected in the exposure area EF.

  The images of the opening patterns 34-11 to 34-19, 34-21 to 34-29, 34-31 to 34-39, 34-41 to 34-49, and 34-51 to 34-59 shown in FIG. Since irradiation is performed from the direction intersecting the X axis and the Y axis at 45 degrees with respect to the surface of W, an image whose longitudinal direction extends in a direction forming an angle of 45 degrees with respect to the X axis and the Y axis is obtained. . The detection points on which these images are projected are arranged along the X and Y directions as shown in FIG. The detection points D11 to D19 arranged on the + Y direction side of the exposure area EF form the first column C1, and the detection points D21 to D29, the detection points D31 to D39, and the detection points D41 to D arranged within the exposure area EF. D49 forms the second column C2, the third column C3, and the fourth column C4, respectively, and the detection points D51 to D59 arranged on the −Y direction side of the exposure region EF form the fifth column C5.

  The illumination light reflected by the wafer W is re-projected on the light receiving surface of the light receiver 31 through the condenser objective lens 28, the rotation direction vibration plate 29, and the imaging lens 30, and pattern formation is performed on the light receiving surface of the light receiver 31. An image of the pattern on the plate 24 is re-imaged. The light receiving surface of the light receiver 31 is provided with a light shielding plate (not shown) in which openings are arranged in a shape similar to the pattern forming plate 24. Here, since the vibrator 33 vibrates the vibrator with a constant frequency and a constant amplitude and applies vibration to the rotational vibration plate 29 formed by mirror-finishing a part of the vibrator. The position of the image projected on 31 vibrates in a direction perpendicular to the longitudinal direction of the opening formed in the light shielding plate, that is, in the width direction of the opening. Detection signals from a number of light receiving elements of the light receiver 31 are supplied to the signal processing device 32. The signal processing device 32 synchronously detects each supplied detection signal with the drive signal of the vibration device 33, and the focus positions of the detection points D11 to D19, D21 to D29, D31 to D39, 41 to D49, D51 to D59. 45 focus signals respectively corresponding to are obtained.

  Here, as shown in FIG. 5, the detection points D21 to D29 in the second column C2 and the detection points D41 to D49 in the fourth column C4 are arranged in the periphery of the exposure area EF, and the detection point D31 in the third column C3. To D39 are arranged inside the exposure area EF, and the detection points D11 to D19 in the first column C1 and the detection points D51 to D59 in the fifth column C5 are arranged outside the exposure area EF. The reason why the detection points D11 to D19 and D51 to D59 are arranged outside the exposure area EF is that the detection results at the detection points D51 to D59 in the fifth column C5 are used when the wafer W is scanned in the + Y direction. This is because the surface shape of the exposed area is measured in advance. Similarly, when the wafer W is scanned in the −Y direction, the surface shape of the region to be exposed is measured in advance using the detection results at the detection points D11 to D19 in the first row C1. Then, using the detection results at the detection points D11 to D19 in the first row C1 or the detection results at the detection points D51 to D59 in the fifth row 5, the posture control of the wafer W is performed on the portion to be exposed. Yes.

  Next, a surface shape measurement method and an attitude measurement method used in the exposure apparatus EX having the above configuration will be described. FIG. 6 is a flowchart showing a surface shape measuring method according to the first embodiment of the present invention. Here, a case where the surface shape of the mirror surface of the movable mirror 12Y is measured using the wafer interferometer 13YP and the multipoint focus position detection system 21 will be described as an example. In this specification, the surface shape includes not only the unevenness of the movable mirror 12Y but also the tilt of the mirror surface of the movable mirror 12Y (tilt with respect to the Z axis). In the present embodiment, in order to facilitate understanding, a case where the inclination (pitching amount) of the mirror surface of the movable mirror 12Y is measured will be mainly described.

  First, a wafer with a guaranteed flatness (for example, a wafer whose surface flatness is higher than the measurement accuracy of the multipoint focus position detection system 21) or a wafer with a known flatness (hereinafter referred to as a test wafer) is exposed. It is carried into apparatus EX and placed on wafer holder 11 provided on wafer stage WST (step S11). This test wafer is carried in the same manner as when a normal wafer W is carried into the exposure apparatus EX using a wafer transfer apparatus (not shown) provided in the exposure apparatus EX.

  When loading of the test wafer is completed, the wafer interferometer 13YP and the multipoint focus position detection system 21 are calibrated to predetermined conditions (step S12). In a state where the wafer interferometer 13YP and the multipoint focus position detection system 21 are calibrated, the leveling amount θAF of the test wafer (wafer stage WST) indicated by the measurement result of the multipoint focus position detection system 21 is 0 [rad. When the wafer stage WST is driven in the rotational direction around the X axis so as to satisfy the following equation, the mirror surface tilt amount (pitching amount) θIF of the movable mirror 12Y is obtained from the detection result of the wafer interferometer 13YP.

  FIG. 7 is a diagram for explaining the leveling amount θAF of the test wafer (wafer stage WST) and the pitching amount θIF of the mirror surface of the movable mirror 12Y. In FIG. 7, laser light LB1 and LB2 irradiated to two places where the position in the X direction is the same from the wafer interferometer 13YP to the mirror of the movable mirror 12Y but the position in the Z direction is different, and the multipoint focus Illumination light DL irradiated onto the test wafer from the position detection system 21 is illustrated. The pitching amount of wafer stage WST is detected by the optical path difference between laser beams LB1 and LB2 irradiated from wafer interferometer 13YP to the mirror surface of movable mirror 12Y.

  Here, the mirror surface of the movable mirror 12Y can be regarded as an ideal plane, and if the movable mirror 12Y is ideally attached to the wafer table 10, as shown in FIG. When the leveling amount θAF of the wafer stage WST measured by the multipoint focus position detection system 21 is 0 [rad], the pitching amount θIF of the mirror surface of the movable mirror 12Y measured by the wafer interferometer 13YP is also 0 [rad]. .

  In reality, however, the mirror surface of the movable mirror 12 </ b> Y is somewhat distorted, and the movable mirror 12 </ b> Y is tilted with respect to the wafer table 10. In this case, as shown in FIG. 7B, the movable mirror 12Y measured by the wafer interferometer 13YP even if the leveling amount θAF of the wafer stage WST measured by the multipoint focus position detection system 21 is 0 [rad]. The pitching amount θIF of the mirror surface does not become 0 [rad]. That is, θAF ≠ θIF. Such a situation also occurs when there is distortion of wafer table 10 (wafer stage WST). For this reason, in this embodiment, the surface shape of the mirror surface of the movable mirror 12Y is measured using the wafer interferometer 13YP and the multipoint focus position detection system 21.

  In a state where the wafer interferometer 13YP and the multipoint focus position detection system 21 are calibrated, the main control system 20 moves the wafer stage WST to a predetermined measurement start position via the wafer drive unit 14. This measurement start position is, for example, a position where the optical axis of the wafer interferometer 13YP passes through one end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction.

  When the movement of wafer stage WST is completed, main control system 20 measures pitching amount θIF with respect to the Z axis of movable mirror 12Y at the measurement start position from the detection result of wafer interferometer 13YP (step S13). Next, the main control system 20 adjusts the amount of expansion / contraction of the three fulcrums 9a to 9c shown in FIG. 2 based on the measured pitching amount θIF of the movable mirror 12Y to adjust the Z axis of the movable mirror 12Y at the measurement start position. The leveling amount of wafer stage WST (attitude of wafer stage WST) is controlled so that the pitching amount θIF with respect to is zero (step S14).

  Next, main control system 20 measures leveling amount θAF of wafer stage WST using multipoint focus position detection system 21 (step S15). Thus, the leveling amount θAF of wafer stage WST when the pitching amount θIF with respect to the Z axis of movable mirror 12Y at the measurement start position is set to zero is obtained. When this leveling amount is obtained, main control system 20 stores the obtained leveling amount θAF in association with the position of wafer stage WST in the X direction.

  Next, the main control system 20 determines whether or not the measurement for the preset measurement range is completed (step S16). This determination is made based on whether or not wafer stage WST has reached the measurement end position. For example, the measurement end position is a position where the optical axis of the wafer interferometer 13YP passes through the other end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction.

  When it is determined that the measurement for the preset measurement range is not completed (when the determination result is “NO”), the main control system 20 moves the wafer stage WST in the X direction via the wafer driving device 14. It is moved by a preset minute distance (step S17). And after moving wafer stage WST, the process of step S13-step S15 is performed. While the determination result of step S16 is “NO”, the processing of step S13 to step S17 is repeated. When the determination result is “YES”, the test wafer is unloaded from the exposure apparatus EX, and a series of measurement processing ends. To do. Through the processing described above, the distribution of the leveling amount of wafer stage WST when the pitching amount θIF with respect to the Z-axis of movable mirror 12Y is always set to zero within the preset measurement range in the X direction is obtained. This distribution indicates the surface shape of the mirror surface of the movable mirror 12Y based on the mirror surface of the movable mirror 12Y.

  When the surface shape of the mirror surface of the movable mirror 12Y is measured by performing the above processing, this surface shape is used to measure the position of the wafer stage WST in the Y direction and the leveling amount of the wafer stage WST. That is, the position and leveling amount in the Y direction of wafer stage WST obtained by receiving each of the laser beams irradiated to the mirror surface of movable mirror 12Y from wafer interferometers 13Y and 13YP are in the surface shape of movable mirror 12Y. It has been affected. Therefore, main control system 20 reads the leveling amount stored in association with the position of wafer stage WST in the X direction, and Y measured from the detection results of wafer interferometers 13Y and 13YP. The direction position and the pitching amount are corrected. Since this process eliminates the influence of the surface shape of the movable mirror 12Y, the main control system 20 controls the position and orientation of the wafer stage WST in the Y direction based on the corrected measurement result.

  As described above, according to the surface shape measuring method of the present embodiment, even if the mirror surface of the movable mirror 14Y is distorted or the wafer table 10 itself is distorted, the position detection accuracy in the Y direction is improved. Can do. Further, according to the attitude measurement method of the present embodiment, similarly to the surface shape measurement method, the leveling amount of the wafer stage WST can be obtained even if the mirror surface of the movable mirror 14Y is distorted or the wafer table 10 itself is distorted. Can be measured with high accuracy.

  In the above embodiment, the case where the surface shape of the mirror surface of the movable mirror 12Y is measured using the wafer interferometer 13YP and the multipoint focus position detection system 21 has been described as an example. The surface shape of the mirror surface of the movable mirror 12X can be similarly measured using the point focus position detection system 21. In this case, the moving direction of wafer stage WST during measurement (the moving direction in step S17 in FIG. 6) is the Y direction.

  When the wafer W is exposed using the exposure apparatus EX described above, the wafer W to be subjected to the exposure process by a wafer transfer apparatus (not shown) is carried into the exposure apparatus EX and held on the wafer holder 11, and A predetermined reticle R is held on reticle stage RST. When the loading of the wafer W and the reticle R is completed, the main control system 20 drives the wafer stage WST to place the wafer W under the wafer alignment sensor 19 (−Z direction). Position measurement of several representative wafer alignment marks on W (about 3 to 9) is performed and EGA calculation is performed, and array coordinates of all shot areas on the wafer W are obtained.

  Next, the main control system 20 sets the coordinate value of the shot area on the wafer W obtained by the above EGA calculation as the baseline amount (the projection center of the projection image via the projection optical system PL and the wafer alignment sensor 19). The coordinate value corrected by (distance from the center of the measurement visual field) is obtained. By driving wafer stage WST using the corrected coordinate values, each shot area on wafer W can be aligned with the exposure area of projection optical system PL. Since the exposure apparatus EX of the present embodiment is a step-and-scan exposure apparatus, when exposing a shot area, the reticle stage RST and the wafer stage WST are moved to the scanning start position and then accelerated. After each of them reaches a predetermined speed and is synchronized, the exposure light EL is emitted to illuminate the reticle R, and an image of the pattern of the reticle R is projected onto the wafer W via the projection optical system PL.

  During scanning, a part of the pattern image of the reticle R is projected onto the exposure area, and the wafer is synchronized with the movement of the reticle R in the −X direction (or + X direction) at the speed V with respect to the projection optical system PL. As W moves in the + X direction (or -X direction) at a speed V / β (1 / β is the projection magnification of the projection optical system PL), the pattern of the reticle R is sequentially transferred to the shot area. The surface shapes of the movable mirrors 12X and 12Y are obtained in advance by the above-described surface shape measurement method. During the scanning exposure, the measurement results of the wafer interferometers 13X, 13XP, 13Y, and 13YP are corrected, and the corrected measurement is performed. Based on the result, the position and orientation of wafer stage WST are controlled.

  When the exposure process for one shot area is completed, the main control system 20 steps the wafer stage WST to move the next shot area to the scanning start position and move the reticle stage RST to the scanning start position. After the movement of both stages is started and each reaches a constant speed and is synchronized, the reticle R is irradiated with the exposure light IL to start exposure, and the shot area is exposed. Similarly, exposure processing for other shot areas is performed. As described above, according to the present embodiment, the measurement results of wafer interferometers 13X, 13XP, 13Y, and 13YP are corrected at the time of exposure, and the position and orientation of wafer stage WST are corrected based on the corrected measurement results. Since control and relative position control with respect to reticle stage RST are performed, exposure accuracy (resolution, transfer fidelity, overlay accuracy, etc.) can be increased.

[Second Embodiment]
The surface shape measurement method, posture measurement method, and exposure method according to the second embodiment of the present invention are performed using the exposure apparatus EX shown in FIG. In the first embodiment of the present invention described above, the surface shape of the mirror surface of the movable mirror 12Y is obtained from the leveling amount θAF with respect to the mirror surface of the movable mirror 12Y. However, in the present embodiment, the attitude of the wafer stage WST (multi-point focus) The surface shape of the mirror surface of the movable mirror 12Y is obtained based on the detection result of the position detection system 21 (leveling amount). FIG. 8 is a flowchart showing a surface shape measuring method according to the second embodiment of the present invention. In the present embodiment, as in the first embodiment, the case where the surface shape of the mirror surface of the movable mirror 12Y is measured using the wafer interferometer 13YP and the multipoint focus position detection system 21 will be described as an example. When the surface shape of the mirror surface of the movable mirror 12X is measured using the wafer interferometer 13XP and the multipoint focus position detection system 21, it can be measured by a method similar to the method described below.

  First, as in the first embodiment, a test wafer is carried into the exposure apparatus EX and placed on the wafer holder 11 provided on the wafer stage WST (step S21). Thereafter, the wafer interferometer 13YP and the multipoint focus position are arranged. The detection system 21 is calibrated to a predetermined condition (step S22). In a state where the wafer interferometer 13YP and the multipoint focus position detection system 21 are calibrated, the main control system 20 moves the wafer stage WST to a predetermined measurement start position via the wafer drive unit 14. This measurement start position is, for example, a position where the optical axis of the wafer interferometer 13YP passes through one end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction.

  When the movement of wafer stage WST is completed, main control system 20 uses multipoint focus position detection system 21 to measure an amount (leveling amount) θAF indicating the posture of wafer stage WST (step S23). Next, main control system 20 adjusts the amount of expansion / contraction of the three fulcrums 9a to 9c shown in FIG. 2 based on the measured leveling amount θAF of wafer stage WST, and makes wafer stage WST in a predetermined posture. (Step S24). The control performed here is, for example, control that makes the surface of the test wafer W horizontal or parallel to the upper surface of the wafer support 7.

  Next, the main control system 20 measures the inclination (pitching amount) θIF with respect to the Z axis of the movable mirror 12Y at the measurement start position from the detection result of the wafer interferometer 13YP (step S25). Thus, the pitching amount θIF with respect to the Z axis of the movable mirror 12Y when the posture of wafer stage WST at the measurement start position is set to a predetermined posture is obtained. When this pitching amount is obtained, main control system 20 stores the obtained pitching amount θIF in association with the position of wafer stage WST in the X direction. Next, the main control system 20 determines whether or not the measurement for the preset measurement range has been completed (step S26). This determination is made based on whether or not wafer stage WST has reached the measurement end position. For example, the measurement end position is a position where the optical axis of the wafer interferometer 13YP passes through the other end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction.

  When it is determined that the measurement for the preset measurement range is not completed (when the determination result is “NO”), the main control system 20 moves the wafer stage WST in the X direction via the wafer driving device 14. It is moved by a preset minute distance (step S27). And after moving wafer stage WST, the process of step S23-step S25 is performed. While the determination result of step S26 is “NO”, the processing of step S23 to step S27 is repeated, and when the determination result is “YES”, the test wafer is unloaded from the exposure apparatus EX, and the series of measurement processing ends. To do. Through the processing described above, the distribution of the pitching amount θIF with respect to the Z axis of the movable mirror 12Y when the wafer stage WST is always controlled to a predetermined posture within the preset measurement range in the X direction is obtained. This distribution indicates the surface shape of the mirror surface of the movable mirror 12Y with reference to the surface of the test wafer.

  When the surface shape of the mirror surface of the movable mirror 12Y is measured by performing the above processing, the surface shape is the position in the Y direction measured from the detection results of the wafer interferometers 13Y and 13YP and the same as in the first embodiment. It is used to correct the pitching amount and measure the position of wafer stage WST in the Y direction and the leveling amount of wafer stage WST. Based on the corrected measurement result, the position and orientation in the Y direction of wafer stage WST are controlled.

  As described above, even in the present embodiment, the flatness of the mirror surface of the movable mirror 14Y is poor, the mounting error of the movable mirror 14Y with respect to the wafer table 10 is large, or even if the wafer table 10 itself is distorted, Position detection accuracy can be improved, and the leveling amount of wafer stage WST can be measured with high accuracy.

[Third Embodiment]
The first and second embodiments described above use the multi-point focus position detection system 21 that detects the position of the surface of the wafer W in the Z direction (optical axis AX direction) at a plurality of detection points. Although the shape was measured, the third embodiment of the present invention measures the surface shape of the mirror surface of the movable mirror using a focus position detection system that detects the position of the surface of the wafer W in the Z direction at one detection point. is doing. FIG. 9 is a flowchart showing a surface shape measuring method according to the third embodiment of the present invention. In this embodiment, as in the first embodiment, the case where the surface shape of the mirror surface of the movable mirror 12Y is measured will be described as an example. However, the surface shape of the mirror surface of the movable mirror 12X may be measured. It can measure by the method similar to the method demonstrated below.

  First, as in the first embodiment, a test wafer is carried into the exposure apparatus EX and placed on the wafer holder 11 provided on the wafer stage WST (step S31), and then the wafer interferometer 13YP and the focus position detection system are arranged. Are calibrated to predetermined conditions (step S32). In a state where the wafer interferometer 13YP and the focus position detection system are calibrated, the main control system 20 moves the wafer stage WST to a predetermined measurement start position via the wafer driving device 14. This measurement start position is, for example, a position where the optical axis of the wafer interferometer 13YP passes through one end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction.

  When the movement of wafer stage WST is completed, main control system 20 measures pitching amount θIF with respect to the Z axis of movable mirror 12Y at the measurement start position from the detection result of wafer interferometer 13YP (step S33). Next, the main control system 20 adjusts the amount of expansion / contraction of the three fulcrums 9a to 9c shown in FIG. 2 based on the measured pitching amount θIF of the movable mirror 12Y to adjust the Z axis of the movable mirror 12Y at the measurement start position. The leveling amount of wafer stage WST (attitude of wafer stage WST) is controlled so that the pitching amount θIF with respect to is zero (step S34).

  Next, the main control system 20 detects the position in the Z direction on the surface of the test wafer with one detection point using the focus position detection system (step S35). When the detection in step S35 is completed, the main control system 20 moves the wafer stage WST by a predetermined amount (ΔY) in the Y direction that intersects the mirror surface of the movable mirror 12Y via the wafer driving device 14 (step S36). Then, the position in the Z direction on the surface of the test wafer is detected at one detection point using the focus position detection system (step S37).

  FIG. 10 is a diagram showing how the posture of wafer stage WST is measured in the third embodiment of the present invention. In the process shown in step S35 in FIG. 9, if the wafer stage WST is at the position indicated by the solid line in FIG. 10, for example, the position in the Z direction of one point on the surface of the test wafer at this time is detected. In the example shown in FIG. 10, the illumination light DL1 from the focus position detection system is irradiated to a location indicated by reference numeral P1 on the surface of the test wafer, and the position of the irradiation position in the Z direction is detected.

  Next, in the process shown in step S36 in FIG. 9, wafer stage WST is moved by ΔX in the Y direction. Thereby, it is assumed that wafer stage WST is arranged at a position indicated by a broken line in FIG. Due to the movement of wafer stage WST, illumination light DL1 from the focus position detection system is irradiated to a location other than the location indicated by symbol P1 (location indicated by symbol P2). If the surface of the test wafer is parallel to the XY plane, even if the wafer stage WST is moved, the position in the Z direction indicated by the symbol P1 and the position in the Z direction indicated by the symbol P2 do not change. However, when wafer stage WST is inclined, the position in the Z direction changes by ΔZ.

Therefore, main control system 20 obtains a change amount ΔZ of the surface position of the test wafer when wafer stage WST is moved by ΔY from the detection result of step S35 and the detection result of step S37. Then, the leveling amount θAF of wafer stage WST is calculated from the following equation (1) using the change amount ΔZ and the movement amount ΔY (step S38).
ΔAF = ΔY / ΔZ (1)
With the above processing, the leveling amount θAF of wafer stage WST when the pitching amount θIF with respect to the Z axis of movable mirror 12Y at the measurement start position is zero is obtained. When this leveling amount is obtained, main control system 20 stores the obtained leveling amount θAF in association with the position of wafer stage WST in the X direction.

  Next, the main control system 20 determines whether or not the measurement for the preset measurement range has been completed (step S39). This determination is made based on whether or not wafer stage WST has reached the measurement end position. For example, the measurement end position is a position where the optical axis of the wafer interferometer 13YP passes through the other end of the test wafer in the X direction with respect to the X direction, and is an arbitrary position with respect to the Y direction. When it is determined that the measurement for the preset measurement range is not completed (when the determination result is “NO”), the main control system 20 moves the wafer stage WST in the X direction via the wafer driving device 14. It is moved by a preset minute distance (step S40). And after moving wafer stage WST, the process of step S33-step S38 is performed.

  While the determination result of step S39 is “NO”, the processing of step S33 to step S40 is repeated. When the determination result is “YES”, the test wafer is unloaded from the exposure apparatus EX, and the series of measurement processing ends. To do. Through the processing described above, the distribution of the leveling amount of wafer stage WST when the pitching amount θIF with respect to the Z-axis of movable mirror 12Y is always set to zero within the preset measurement range in the X direction is obtained. This distribution indicates the surface shape of the mirror surface of the movable mirror 12Y based on the mirror surface of the movable mirror 12Y.

  When the surface shape of the mirror surface of the movable mirror 12Y is measured by performing the above processing, the surface shape is the position in the Y direction measured from the detection results of the wafer interferometers 13Y and 13YP and the same as in the first embodiment. It is used to correct the pitching amount and measure the position of wafer stage WST in the Y direction and the leveling amount of wafer stage WST. Based on the corrected measurement result, the position and orientation in the Y direction of wafer stage WST are controlled. As described above, even in the present embodiment, the flatness of the mirror surface of the movable mirror 14Y is poor, the mounting error of the movable mirror 14Y with respect to the wafer table 10 is large, or even if the wafer table 10 itself is distorted, Position detection accuracy can be improved, and the leveling amount of wafer stage WST can be measured with high accuracy.

  The case where the surface shape of the mirror surface of the movable mirror 12Y is measured with reference to the mirror surface of the movable mirror 12Y using the focus position detection system that detects the position of the surface of the wafer W in the Z direction at one detection point will be described. However, the surface shape of the mirror surface of the movable mirror 12Y can be measured using this focus position detection system in substantially the same procedure as the flowchart shown in FIG. When performing such measurement, “multi-point focus position detection system” in FIG. 8 may be read as “focus position detection system” and step S23 in FIG. 8 may be replaced with S35 to S38 in FIG.

  In the first to third embodiments described above, the case where the surface shape of the mirror surface of the movable mirror 12Y is measured with the test wafer placed on the wafer holder 11 has been described as an example. In the case of the wafer stage WST including a wafer holder whose flatness is guaranteed or having a known flatness, illumination from the light transmission system 21a included in the multipoint focus position detection system 21 without using a test wafer. The posture of wafer stage WST may be measured by irradiating light on the upper surface of the wafer holder.

  As shown in FIG. 11, reflectors 40X and 40Y whose upper surfaces are mirror-finished to ensure flatness or reflectors 40X and 40Y with known flatness are provided on the wafer table 10, and a multipoint focus position detection system is provided. The attitude of wafer stage WST may be measured by irradiating reflectors 40X and 40Y with illumination light DL 21 from 21 or illumination light DL1 from a focus position detection system (not shown). FIG. 11 is a perspective view showing wafer stage WST including reflection plates 40X and 40Y on wafer table 10. As shown in FIG.

  In the example shown in FIG. 11, the height position is substantially the same as the height position of the wafer W, and the height position is substantially the same as the height position of the wafer W. In addition, a reflector 40Y whose longitudinal direction is set to the X direction is provided in the vicinity of the wafer holder 11 on the wafer table 10. The lengths of the reflecting plates 40X and 40Y in the longitudinal direction are set to be approximately the same as the diameter of the wafer W, and the central portion of the reflecting plate 40X is arranged on a straight line passing through the center of the wafer W and parallel to the X axis. A central portion of the reflector 40Y is disposed on a straight line that passes through the center of the wafer W and is parallel to the Y axis.

  When measuring the surface shape of the mirror surface of the movable mirror 12X, the illumination light DL from the multipoint focus position detection system 21 or the illumination light DL1 from the focus position detection system (not shown) is irradiated on the upper surface of the reflection mirror 40X. Then, the attitude of wafer stage WST is measured. Further, when measuring the surface shape of the mirror surface of the movable mirror 12Y, the illumination light DL from the multipoint focus position detection system 21 or the illumination light DL1 from the focus position detection system (not shown) is irradiated on the upper surface of the reflecting mirror 40Y. Then, the attitude of wafer stage WST is measured.

  Furthermore, when the posture of wafer stage WST is measured using multipoint focus position detection system 21, in the above embodiment, detection points D11 to D19 and D51 to D59 are set in the ± Y direction of exposure area EF, respectively. The point focus position detection system 21 has been described as an example. However, the multipoint focus position detection system 21 uses a detection point set only in one of the exposure area EF and the outside, or a detection point set only in the exposure area EF. You can also. Further, the multipoint focus position detection system 21 has been described by taking an example in which 45 detection points are set. However, it is only necessary that detection points are set at least at two different points on the wafer W. . Furthermore, the arrangement of the detection points may be arbitrary.

  In the above embodiment, the case where the surface shape of the movable mirror 12 (12X, 12Y) provided mainly on the wafer stage WST is measured has been described. However, the mirror surface of the movable mirror 4 provided on the reticle stage RST The present invention can also be applied when measuring the surface shape. Further, the present invention is not limited to measuring the surface shape of the mirror surface of the movable mirror provided in the reticle stage RST and wafer stage WST provided in the exposure apparatus EX, and is configured to be able to place and move an object. In general, the present invention can be applied to the case of measuring the surface shape of the mirror surface of the movable mirror provided in the stage device.

  Further, as the exposure apparatus EX, a step-and-scan type reduction projection type exposure apparatus has been described as an example, but the present invention can also be applied to a scanning exposure type projection exposure apparatus such as a scanning stepper. Moreover, it is used not only for the exposure apparatus used for the manufacture of semiconductor elements, but also for the manufacture of displays including liquid crystal display elements (LCD), etc., and for the manufacture of exposure apparatuses that transfer device patterns onto glass plates and the production of thin film magnetic heads. Thus, the present invention can also be applied to an exposure apparatus that transfers a device pattern onto a ceramic wafer, an exposure apparatus that is used for manufacturing an image sensor such as a CCD, and the like.

  Furthermore, in an exposure apparatus that transfers a circuit pattern onto a glass substrate or a silicon wafer in order to manufacture a reticle or mask used in an optical exposure apparatus, EUV exposure apparatus, X-ray exposure apparatus, electron beam exposure apparatus, or the like. The present invention can also be applied. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate. Such an exposure apparatus is disclosed in WO99 / 34255, WO99 / 50712, WO99 / 66370, JP-A-11-194479, JP-A2000-12453, JP-A-2000-29202, and the like. .

  The present invention can also be applied to an exposure apparatus using a liquid immersion method as disclosed in International Publication No. 99/49504. In the present invention, an immersion exposure apparatus that locally fills the space between the projection optical system PL and the wafer W with a liquid, a substrate to be exposed as disclosed in JP-A-6-124873, is held. An immersion exposure apparatus for moving a stage in a liquid tank, a liquid tank having a predetermined depth formed on a stage as disclosed in JP-A-10-303114, and holding a substrate in the liquid tank The present invention can be applied to any exposure apparatus of the exposure apparatus.

  FIG. 12 is a flowchart showing an example of a manufacturing process of a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 11, the microdevice such as a semiconductor device includes a step (S51) for designing a function / performance of the microdevice, a step (S52) for producing a mask (reticle) based on the design step, and a substrate (device substrate). Wafer), an exposure processing step S54 for transferring the mask pattern onto the substrate by the exposure apparatus EX of the above-described embodiment, a device assembly step (including a dicing process, a bonding process, and a packaging process) S55, and an inspection step S56. And so on.

It is a figure which shows schematic structure of the exposure apparatus in which the surface shape measuring method, attitude | position measuring method, and exposure method by 1st Embodiment of this invention are used. It is a perspective view which shows the structure of wafer stage WST and wafer interferometer 13. FIG. 2 is a diagram illustrating a configuration of an oblique incidence type multi-point focus position detection system 21. FIG. 4 is a cross-sectional view showing a configuration example of a pattern forming plate 24. FIG. 6 is a diagram showing a projected image of an aperture pattern projected on a plurality of detection points set in and near an exposure area on a wafer W. FIG. It is a flowchart which shows the surface shape measuring method by 1st Embodiment of this invention. It is a figure for demonstrating leveling amount (theta) AF of a test wafer (wafer stage WST), and pitching amount (theta) IF of the mirror surface of the movable mirror 12Y. It is a flowchart which shows the surface shape measuring method by 2nd Embodiment of this invention. It is a flowchart which shows the surface shape measuring method by 3rd Embodiment of this invention. In 3rd Embodiment of this invention, it is a figure which shows a mode that the attitude | position of wafer stage WST is measured. It is a perspective view which shows wafer stage WST provided with the reflecting plates 40X and 40Y on the wafer table 10. FIG. It is a flowchart which shows an example of the manufacturing process of a microdevice.

Explanation of symbols

7 Wafer support (reference plane)
12, 12X, 12Y Moving mirror (reflection surface)
DL illumination light (measurement beam)
R reticle (mask)
W wafer (photosensitive object)
WST Wafer stage (moving body)

Claims (6)

A surface shape measurement method for measuring a shape of a reflection surface provided on a moving body that moves along a reference plane orthogonal to a first axis and extending along a second axis direction orthogonal to the first axis direction,
A first step of measuring an inclination of the reflecting surface with respect to the first axis;
A second step of controlling the posture of the movable body so that the inclination of the reflecting surface with respect to the first axis becomes zero based on the measurement result of the first step;
A third step of measuring the posture of the moving body with respect to the reference plane;
And a fourth step of repeating the first step to the third step while moving the movable body along the second axial direction. A surface shape measurement method for measuring a shape of a reflection surface provided on a moving body that moves along a reference plane orthogonal to a first axis and extending along a second axis direction orthogonal to the first axis direction,
A first step of measuring a posture of the moving body with respect to the reference plane;
A second step of controlling the posture of the moving body to a predetermined posture based on the measurement result of the first step;
A third step of measuring an inclination of the reflecting surface with respect to the first axis in a state where the movable body is controlled to the predetermined posture;
And a fourth step of repeating the first step to the third step while moving the movable body along the second axial direction. The moving body has an object placement surface that intersects the first axis,
The surface shape measuring method according to claim 2, wherein the predetermined posture of the moving body is a posture in which the object placement surface is parallel to the reference plane. The moving body has an object placement surface that intersects the first axis,
4. The posture of the movable body is obtained by measuring positions in the first axis direction at at least two different positions on the object placement surface. 5. The surface shape measuring method described in 1. A movable body having a reflecting surface extending along a second axis direction orthogonal to the first axis direction and moving along a reference plane orthogonal to the first axis is defined as the posture of the reflecting surface with respect to the reference plane. A posture measurement method for measuring with a measurement beam simultaneously irradiated to two positions separated in a first axis direction,
Measuring the surface shape of the reflecting surface by the surface shape measuring method according to any one of claims 1 to 4;
Irradiating the measurement surface simultaneously with the measurement beam to receive each reflected light from the reflection surface, and measuring the inclination of the reflection surface with respect to the first axis from the light reception result;
Correcting the tilt measurement result of the reflecting surface based on the measurement result of the surface shape, and obtaining the posture of the moving body with respect to the reference plane. In an exposure method for transferring a mask pattern onto a photosensitive object held by a movable body movable along a reference plane perpendicular to the first axis,
6. An exposure method according to claim 5, wherein the movement of the movable body is controlled based on the measurement result of the attitude measurement method according to claim 5.

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