JP2011049286A - Measurement method and apparatus, and exposure method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and accurately measure optical characteristics of a projection optical system without upsizing an optical system for measurement. <P>SOLUTION: In a measurement apparatus for measuring the optical characteristics of a projection optical system PL, the measurement apparatus includes a reticle mark plate RFM formed with phase marks 20 disposed at a plurality of measurement points P(i, j) on an object face, a fluorescence screen 35 formed with a periodic pattern 39 disposed at a position on an image face corresponding to the measurement point P(i, j), an FOP 37 for guiding a detection light DL created by an illuminating light IL which has passed the phase mark 20, the projection optical system PL, and the periodic pattern 39 to a detection face, and an image sensor 38 for detecting the detection light DL. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a measurement technique for measuring the optical characteristics of a projection optical system, an exposure technique using this measurement technique, and a device manufacturing technique using this exposure technique.

  In an exposure apparatus used in a lithography process for manufacturing an electronic device (microdevice) such as a semiconductor device, a pattern formed on a reticle or the like is transferred to a substrate such as a wafer with high accuracy via a projection optical system. Therefore, it is necessary to maintain the optical characteristics (for example, distortion, curvature of field, wavefront aberration, etc.) of the projection optical system in a predetermined state. For this purpose, it is necessary to measure the optical characteristics of the projection optical system with high accuracy, for example, periodically during exposure.

As a conventional measurement technique, an image of a phase pattern formed through a projection optical system is detected by a photoelectric sensor through two periodic patterns, and the phase pattern image is detected from the difference between detection signals of these photoelectric sensors. A measuring device that detects a focus position (defocus amount) is known (see, for example, Patent Document 1).
As another conventional measurement technique, two linear pattern images formed via a projection optical system are detected by photoelectric sensors via two wedge-shaped opening patterns, and detection signals of these photoelectric sensors are detected. There is known a measuring device that detects the amount of lateral shift (and hence distortion) of the image of the linear pattern from the difference between them (see, for example, Patent Document 2).

International Publication No. 2009/001834 Pamphlet International Publication No. 2009/001835 Pamphlet

  In order to efficiently measure the optical characteristics of the projection optical system, the image states of a plurality of measurement patterns are measured in a large area covering the entire exposure area in the image plane of the projection optical system. It is preferable. However, in a conventional device that directly receives detection light with a plurality of photoelectric sensors via a detection pattern such as a periodic pattern or an aperture pattern, if the light receiving area is widened, disturbance light or an image different from the image to be detected From the light incident on each photoelectric sensor, the measurement accuracy may vary depending on the detection position on the image plane.

Further, since the photoelectric sensor serves as a heat source, it is preferable to dispose the photoelectric sensor as far as possible from the image plane in order to suppress thermal deformation or the like of the detection pattern. However, if a relay lens is arranged between a plurality of detection patterns and a plurality of photoelectric sensors for this purpose, the measuring device becomes large.
In view of such circumstances, it is an object of the present invention to efficiently and accurately measure the optical characteristics of a projection optical system without increasing the size of an optical system for measurement.

  A measuring device according to the present invention is a measuring device that measures optical characteristics of a projection optical system that forms an image of a pattern of a first surface on a second surface, and a plurality of devices arranged at a plurality of measuring points on the first surface. A first pattern forming member on which a first pattern is formed, a second pattern forming member on which a plurality of second patterns arranged at positions corresponding to the plurality of measurement points on the second surface are formed, and a plurality of A light guide member formed by bundling optical fibers and guiding detection light generated by illumination light that has passed through the plurality of first patterns, the projection optical system, and the plurality of second patterns to the detection surface, and the detection surface And a photoelectric detector including a plurality of pixels for detecting the detection light guided by the light guide member, and processing for obtaining the optical characteristics by processing the detection result of the photoelectric detector And a device Than is.

  Further, the measurement method according to the present invention is a measurement method for measuring optical characteristics of a projection optical system that forms an image of a pattern on a first surface on a second surface, and the measurement method is applied to each of a plurality of measurement points on the first surface. One pattern is arranged, a second pattern is arranged at a position corresponding to the plurality of measurement points on the second surface, the plurality of the first patterns are illuminated with illumination light, the first pattern, and the projection optical system And the detection light generated by the illumination light that has passed through the second pattern is guided to the detection surface through a light guide member formed by bundling a plurality of optical fibers, and is guided to the detection surface by the light guide member. The detected light is detected through a photoelectric detector having a plurality of pixels, and the detection result of the photoelectric detector is processed to obtain its optical characteristics.

An exposure apparatus or exposure method according to the present invention is an exposure apparatus or exposure method that exposes a pattern on an object via a projection optical system, in order to measure the optical characteristics of the projection optical system. A measurement method is used.
A device manufacturing method according to the present invention includes forming a pattern of a photosensitive layer on a substrate using the exposure apparatus or exposure method of the present invention, and processing the substrate on which the pattern is formed. .

  According to the present invention, the images of the projection optical system of the first pattern at a plurality of measurement points are collectively detected by the photoelectric detector via the second pattern and the light guide member at the corresponding positions. Thus, by passing through the light guide member, disturbance light having a large incident angle can be eliminated, and the formation surface of the second pattern and the light receiving surface of the photoelectric detector can be separated. Therefore, the optical characteristics of the projection optical system can be measured efficiently and accurately without increasing the size of the measurement optical system.

It is a perspective view which shows the exposure apparatus of 1st Embodiment. 1A is a diagram showing an imaging unit 32 that is measuring the optical characteristics of the projection optical system in FIG. 1, FIG. 2B is a plan view showing a reticle mark plate RFM in FIG. 2A, and FIG. It is a top view which shows the imaging unit 32 of A). 2A is an enlarged plan view showing one phase mark 20 in FIG. 2B, FIG. 2B is an enlarged cross-sectional view showing the phase mark 20, and FIG. 2C is an example of the light intensity distribution of the image of the phase mark 20. FIG. 2A is an enlarged plan view showing a set of periodic patterns and the like of the imaging unit 32 in FIG. 2C, FIG. 2B is a diagram showing an example of a focus signal, and FIG. 2C is an image plane of the projection optical system PL. It is a figure which shows an example of a measurement result. It is a flowchart which shows an example of measurement operation | movement of an optical characteristic, and exposure operation | movement. It is a figure which shows the imaging unit 32 which is measuring the image plane of a projection optical system. (A) is an enlarged sectional view showing three types of phase marks having different pitches, and (B) is an enlarged plan view showing three sets of periodic patterns of the imaging unit for detecting the image of the phase mark in FIG. 7 (A). (C) is a figure which shows the projection optical system which is measuring spherical aberration. It is the figure which notched the part which shows the principal part of the exposure apparatus of 2nd Embodiment. (A) is a figure which shows an example of the measurement result of the focus position of 2nd Embodiment, (B) is a figure which shows the abnormal value in the measurement result of FIG. 9 (A). (A) is a figure which shows the principal part of the exposure apparatus of 3rd Embodiment, (B) is a top view which shows the reticle mark board RFM of FIG. 10 (A), (C) is an imaging unit of FIG. 10 (A). It is a top view which shows 32A. FIG. 11 is an enlarged plan view showing a plurality of evaluation marks in the vicinity of one measurement point in FIG. It is an enlarged plan view showing one set of detection patterns of the imaging unit of the third embodiment. (A) is an enlarged plan view showing an image of an evaluation mark projected on the imaging unit in FIG. 12, (B) is a diagram showing an example of a detection signal corresponding to the amount of image misregistration, and (C) is a projection. It is an enlarged plan view showing an example of distortion of an image. It is a flowchart which shows an example of the manufacturing process of an electronic device.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a scanning exposure type exposure apparatus EX composed of a scanning stepper (scanner) according to the present embodiment. In FIG. 1, the exposure apparatus EX includes an exposure light source (not shown) and an illumination optical system ILS that illuminates a reticle R (mask) with exposure illumination light (exposure light) IL emitted from the exposure light source. ing. Further, the exposure apparatus EX includes a reticle stage RST that holds and moves the reticle R, a projection optical system PL that projects the illumination light IL emitted from the reticle R onto the wafer W (substrate), and positioning and positioning of the wafer W. It includes a wafer stage WST that moves, a main control system 2 that includes a computer that controls the overall operation of the apparatus, and other drive systems.

  Hereinafter, the Z-axis is taken in parallel with the optical axis AX of the projection optical system PL, the X-axis and the Y-axis are taken in two orthogonal directions within a plane (substantially a horizontal plane), and the X-axis, Y-axis, and Z-axis are taken. The description will be made assuming that the rotation (inclination) directions around the axis parallel to the axis are the θx, θy, and θz directions, respectively. In the present embodiment, the scanning direction of reticle R and wafer W during scanning exposure is a direction parallel to the Y axis (Y direction).

An ArF excimer laser (wavelength 193 nm) is used as the exposure light source. Other exposure light sources include ultraviolet pulse laser light sources such as KrF excimer laser (wavelength 248 nm), harmonic generation light source of YAG laser, harmonic generator of solid-state laser (semiconductor laser, etc.), discharge lamp such as mercury lamp, etc. Can also be used.
The illumination optical system ILS includes an illuminance uniformizing optical system including an optical integrator (a fly-eye lens, a rod integrator, a diffractive optical element, etc.) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. It includes a reticle blind (variable field stop) and a condenser optical system. An aperture stop corresponding to the pupil plane (illumination pupil plane) in the illumination optical system ILS by a setting mechanism (not shown) according to illumination conditions such as normal illumination, annular illumination, or quadrupole (or dipole) illumination. May be installed.

At the time of exposure, the illumination optical system ILS illuminates a rectangular illumination region 18R elongated in the X direction (non-scanning direction) on the pattern region (lower surface) of the reticle R with illumination light IL with a substantially uniform illuminance distribution.
The reticle R is sucked and held on the reticle stage RST via a reticle holder (not shown). Reticle stage RST is mounted on an upper surface of reticle base 14 parallel to the XY plane via an air bearing, and moves on the upper surface at a constant speed in the Y direction, as well as a position in X direction, Y direction, and a rotation angle in θz direction. Make fine adjustments. As an example, two-dimensional positional information including the position of the reticle stage RST in at least the X direction and the Y direction and the rotation angle in the θz direction includes an X-axis laser interferometer 16X and a Y-axis two-axis laser interferometer 16YA. , 16YB, and the measured value is supplied to the stage drive system 4 and the main control system 2. The stage drive system 4 controls the speed and position of the reticle stage RST via a drive mechanism (not shown) based on the position information and the control information from the main control system 2.

  A rectangular flat reticle mark plate RFM elongated in the X direction is fixed to the upper surface of the reticle stage RST in the Y direction so as to be adjacent to the reticle R, and the pattern surface of the reticle mark plate RFM (the pattern surface of the reticle R) A predetermined evaluation mark (described later) is formed on a surface having the same height. In reticle stage RST, an opening for allowing illumination light IL to pass is formed so as to surround the pattern areas of reticle R and reticle mark plate RFM, and an opening for allowing illumination light IL to pass through an area opposite to illumination area 18R of reticle base 14. Is formed.

  Under the illumination light IL, the circuit pattern in the illumination region 18R of the reticle R is given a predetermined projection magnification (for example, 1/4, 1/1) via the projection optical system PL of both-side telecentric (or one-side telecentric on the wafer side). And an exposure area 18W (an area conjugate to the illumination area 18R) on one shot area SA on the wafer W. The wafer W is obtained by applying a photoresist (photosensitive agent) on a disk-like base material such as silicon having a diameter of 200 mm or 300 mm, for example. The projection optical system PL is, for example, a refractive system, but a catadioptric system or the like can also be used. The pattern surface of the reticle is disposed on the object surface of the projection optical system PL, and the surface (exposure surface) of the wafer W is disposed on the image surface of the projection optical system PL.

  Further, the exposure apparatus EX includes a characteristic control mechanism that controls optical characteristics such as distortion, field curvature, and spherical aberration of the projection optical system PL. The characteristic control mechanism includes driving elements 12A and 12B such as piezo elements that can be expanded and contracted in the Z direction, and driving elements 12A and 12B. A drive system 10 that controls the amount, and a characteristic control system 8 that controls the positions and tilt angles of the lenses L1 and L2 via the drive system 10 according to control information from the main control system 2 are provided. Note that the number and arrangement of the lenses to be driven are set according to the imaging characteristics of the object to be controlled.

  On the other hand, wafer W is attracted and held on wafer stage WST via wafer holder WH. Wafer stage WST includes an XY stage 24 and a Z tilt stage 22 provided thereon and provided with a wafer holder WH for holding wafer W. The XY stage 24 is placed on an upper surface parallel to the XY plane of the wafer base 26 via an air bearing, and the upper surface moves in the X direction and the Y direction, and the rotation angle in the θz direction is corrected as necessary. . The Z tilt stage 22 has a focus leveling mechanism (not shown) including, for example, three Z drive units that can be displaced in the Z direction. By driving this focus leveling mechanism, the upper surface of the Z tilt stage 22 (wafer) It is possible to control the position of W) in the optical axis AX direction (focus position or Z position) and the inclination angles in the θx direction and the θy direction.

  In addition, an imaging unit 32 for measuring the state of an image of the plurality of evaluation marks on the reticle mark plate RFM by the projection optical system PL is fixed in the vicinity of the wafer holder WH on the Z tilt stage 22. The surface on which the detection pattern on the upper part of the imaging unit 32 is formed is set at almost the same height as the surface of the wafer W, and the detection pattern is covered with a protective film 34 (details will be described later).

  Further, on the side surface of the projection optical system PL, for example, focus positions at a plurality of points on the surface to be measured such as the surface of the wafer W having the same configuration as that disclosed in US Pat. No. 5,448,332, for example. An oblique incidence type multi-point autofocus sensor (not shown) for measuring (Z position) is provided. The stage drive system 4 drives the Z tilt stage 22 by an autofocus method so that the test surface maintains a predetermined relationship with the image plane of the projection optical system PL based on the measurement result of the autofocus sensor. To do.

  Two-dimensional position information including at least the position in the X direction and the Y direction of the wafer stage WST (Z tilt stage 22) and the rotation angle in the θz direction is, for example, two-axis laser interferometers 28XP and 28XF of the X axis. The measurement values are measured by a wafer side interferometer including two Y-axis laser interferometers 28YA and 28YB, and the measured values are supplied to the stage drive system 4 and the main control system 2. The stage drive system 4 determines the two-dimensional position of the XY stage 24 of the wafer stage WST via a drive mechanism (not shown) based on the position information and the control information from the main control system 2. Control.

  Further, on the side surface of the projection optical system PL, for example, an image processing type wafer alignment system 30 in an off-axis system for measuring the position of the alignment mark on the wafer W is supported by a frame (not shown). An aerial image measurement system (not shown) for detecting an image such as an alignment mark (not shown) of the reticle R is installed in the Z tilt stage 22. The detection results of the aerial image measurement system and the wafer alignment system 30 are supplied to an alignment control system (not shown), and the reticle R and the wafer W can be aligned based on the detection results.

  At the time of exposure, the reticle stage RST and wafer stage WST are driven while exposing an image of the pattern in the illumination area 18R of the reticle R by the projection optical system PL onto one shot area on the wafer W, so that the reticle R and the wafer are driven. By moving W in the Y direction in synchronism with the projection magnification as the speed ratio, the pattern image of the reticle R is scanned and exposed in the shot area. After that, the wafer stage WST is driven to move the wafer W stepwise in the X and Y directions, and the scanning exposure operation is repeated, so that the reticle is applied to each shot area on the wafer W by the step-and-scan method. An R pattern image is exposed.

  In this exposure, for example, the optical characteristics of the projection optical system PL gradually vary depending on the integrated irradiation energy of the illumination light IL with respect to the projection optical system PL and the ambient atmospheric pressure (atmospheric pressure). A characteristic control mechanism including the characteristic control system 8 and the drive elements 12A and 12B is driven. Further, when the best focus position as the optical characteristic varies, for example, the Z tilt stage 22 is driven according to the variation amount. Further, as an example, there is a measuring device including a reticle mark plate RFM and an imaging unit 32 in order to measure the fluctuation amount (residual aberration) of the optical characteristics of the projection optical system PL that remains even if the characteristic control mechanism is used. used. That is, when measuring the optical characteristics of the projection optical system PL, by driving the reticle stage RST and the wafer stage WST, as shown in FIG. 2A, the pattern area of the reticle mark plate RFM becomes the illumination light IL. Is moved to the illumination area 18R, and the upper surface of the imaging unit 32 of the wafer stage WST is moved to the exposure area 18W. 2B and 2C are plan views showing the reticle mark plate RFM and the imaging unit 32 of FIG.

  As shown in FIG. 2B, the pattern area in the illumination area 18R of the reticle mark plate RFM is arranged at predetermined intervals in the X direction and the Y direction, in the I direction in the X direction and in the J column in the Y direction. I × J measurement points are set, and the i-th measurement point in the + X direction and the j-th measurement point in the + Y direction are P (i, j) (1 ≦ i ≦ I, 1 ≦ j ≦ J). . The integer I is, for example, about 10 to 20, and the integer J is, for example, about 5 to 10. In the example of FIG. 2B, I = 13 and J = 7. In addition, phase marks 20 as evaluation marks are formed so that the centers are located at the respective measurement points P (i, j). Further, alignment marks FM1 and FM2 are formed at both ends in the X direction of the pattern region. In FIG. 2A and the like, the measurement point P (i, j) is arranged on the optical axis AX for convenience of explanation, but its position is arbitrary.

  As shown in the enlarged plan view of FIG. 3A and the cross-sectional view of FIG. 3B, the phase mark 20 has a plurality of rectangular recesses 20a elongated in the Y direction at a pitch (period) in the X direction (measurement direction). ) Made of P1. The width of the concave portion 20a in the X direction and the width of the convex portion 20b between them in the X direction are substantially equal. When the projection magnification of the projection optical system PL is β, the value of the pitch P1 at the stage of the projected image (= β · P1) is, for example, several μm to several tens of μm. Further, when the wavelength of the light (illumination light IL) irradiated to the phase mark 20 is λ, the phase of the light passing through the concave portion 20a and the light passing through the convex portion 20b using a positive or negative odd number n. The phase difference φ with respect to the phase is set as follows. In this case, the phase difference φ is approximately 90 ° or 270 ° (−90 °).

φ = nλ / 4 (1)
In the present embodiment, the phase difference φ of the light passing through the convex portion 20b relative to the light passing through the concave portion 20a is set to approximately 90 ° (n =..., -7, -3, 1, 5,...). ing. The phase difference φ of the light passing through the convex portion 20b relative to the light passing through the concave portion 20a may be set to approximately 270 ° (n =..., -5, -1, 3, 7,...).

  In this case, assuming that the phase mark 20 in FIG. 3B is arranged on the object plane of the projection optical system PL, the light intensity distribution in the X direction of the image of the projection optical system PL of the phase mark 20 is as shown in FIG. It becomes like IA1, IA2, IA3 of (C). In FIG. 3C, a light intensity distribution IA1 is a distribution when a measurement surface for measuring an image of the phase mark 20 (a surface on which a detection pattern described later is disposed) is at the best focus position of the projection optical system PL. In addition, the light intensity distribution IA1 has a peak having the same value at the center of the image of the concave portion 20a and the convex portion 20b of the phase mark 20. Therefore, the light intensity distribution IA1 has a sine wave shape with a pitch β · P1 / 2 in the X direction.

  The light intensity distribution IA2 is a distribution when the measurement surface is shifted in the + Z direction (upward) with respect to the best focus position of the projection optical system PL. The light intensity distribution IA2 is an image of the convex portion 20b of the phase mark 20. The peak at the center of becomes smaller. Further, the light intensity distribution IA3 is a distribution when the measurement surface is shifted in the −Z direction with respect to the best focus position of the projection optical system PL, and the light intensity distribution IA3 is the center of the image of the recess 20a of the phase mark 20. The peak of becomes smaller. Furthermore, the difference between the peak of the image of the concave portion 20a and the peak of the image of the convex portion 20b increases as the defocus amount on the measurement surface increases. The imaging unit 32 measures the defocus amount of the light receiving surface based on changes in the light intensity distributions IA1 to IA3 due to such a defocus state.

  2A, the image pickup unit 32 is installed on a detection surface 38a in which a two-dimensional image pickup element 38 made of CCD or CMOS and a large number of pixels of the image pickup element 38 are arranged in a grid in the X and Y directions. A fiber optic plate (hereinafter referred to as FOP) 37 formed by bundling a large number of optical fibers that transmit visible light, a wavelength selection film 36 formed on an incident surface (upper surface) of the FOP 37, and a wavelength selection film 36 The fluorescent film 35 formed thereon, a plurality of periodic patterns 39 as detection patterns formed on the upper surface (measurement surface) of the fluorescent film 35, and formed on the fluorescent film 35 so as to cover these periodic patterns 39. The protective film 34 is provided.

  The illumination light IL that has passed through the projection optical system PL is incident on the fluorescent film 35 via the protective film 34 and the periodic pattern 39. The fluorescent film 35 generates detection light DL in the visible range as fluorescence with high conversion efficiency by irradiation of the illumination light IL that is ultraviolet light, and the detection light DL and the unconverted ultraviolet light are incident on the wavelength selection film 36. . The wavelength selection film 36 transmits the detection light DL to the FOP 37 side and reflects the ultraviolet light (illumination light IL) that has not been converted. The detection light DL is guided to the detection surface 38a on which a large number of pixels of the image sensor 38 are arranged in a state where the light intensity distribution on the incident surface is maintained by the FOP 37, and the detection signal of the image sensor 38 is sent to the arithmetic unit 6 in FIG. Supplied. The arithmetic device 6 processes the detection signal to obtain a predetermined imaging characteristic of the projection optical system PL. The protective film 34 protects the lower layer film from air and water vapor. Note that when the imaging unit 32 is used in an exposure apparatus that performs immersion exposure, the protective film 34 is preferably water-resistant or water-repellent.

  As shown in FIG. 2C, the shape of the upper surface of the image pickup unit 32, the cross-sectional shape of the FOP 37, and the shape of the detection surface 38a of the image pickup element 38 are wider in the X and Y directions than the exposure region 18W. Is set. The width of the exposure region 18W in the X direction is, for example, about 26 mm, the width in the Y direction (slit width) is, for example, about 8 mm, and the detection surface 38a of the image sensor 38 has, for example, a width in the X direction of about 30 mm and a width in the Y direction. It may be about 10 mm. The FOP 37 is obtained by bundling optical fibers having an outer diameter of about 3 to 6 μm that transmit a large number of visible light so that the incident surface and the exit surface are in the same array, and polishing the entrance surface and the exit surface. The height of the FOP 37 is, for example, about several mm to 20 mm. As FOP37, products such as Hamamatsu Photonics Co., Ltd. or Schott can be used. As the image sensor 38, an image sensor having a pixel size of about 10 μm or larger can be used. The total thickness of the fluorescent film 35 and the wavelength selection film 36 is preferably about the diameter of one optical fiber constituting the FOP 37 or thinner than this in order to maintain a high lateral resolution.

The protective film 34 is a silicon dioxide thin film, for example. The fluorescent film 35 is formed of, for example, a material obtained by doping a base material of fluoride (for example, lanthanum fluoride (LaF ₃ )) with an activator (for example, europium (Eu)) selected from a transition metal and a rare earth element. . The concentration of the activator is set, for example, in the range of 1 mol% to 10 mol% as a cation ratio with respect to the fluoride base material, and preferably about 5 mol%. The wavelength selection film 36 is composed of a dielectric multilayer mirror that transmits visible light and reflects ultraviolet light, for example.

  The center of a large number of periodic patterns 39 formed on the upper surface of the fluorescent film 35 of the imaging unit 32 projects the array of measurement points P (i, j) on the reticle mark plate RFM as shown in FIG. They are arranged at measurement points Q (i, j) (i = 1 to I, j = 1 to J) set in an array reduced by the projection magnification β of the system PL. Since the projection optical system PL of the present embodiment forms an inverted image, the arrangement of the measurement points Q (i, j) is an inversion of the arrangement of the measurement points P (i, j) with respect to the arrangement center. is there. When measuring the optical characteristics of the projection optical system PL, the measurement point Q (i, j) of the imaging unit 32 is arranged at a position conjugate with respect to the measurement point P (i, j) of the reticle mark plate RFM and the projection optical system PL. .

  As shown in the enlarged view of FIG. 4A, the periodic pattern 39 at the measurement point Q (i, j) in FIG. 2C has a plurality of widths β · P1 / 2 elongated in the Y direction in the light shielding film. Of the aperture pattern 39Aa is arranged with a phase shift with respect to the aperture pattern 39Aa so that the aperture pattern 39Aa is positioned between the aperture pattern 39Aa and the first periodic pattern 39A formed with the pitch β · P1 in the X direction. A second periodic pattern 39B in which a plurality of opening patterns 39Ba having the same size as the opening pattern 39Aa is formed with a period β · P1 in the X direction is formed close to the Y direction. The length of the periodic pattern 39 in the Y direction is set to be somewhat longer than the length of the image 20P of the phase mark 20 in the Y direction. At the time of measuring the optical characteristics of the projection optical system PL, almost half of the −Y direction and the + Y direction of the image 20P of the phase mark 20 at the measurement point P (i, j) are on the periodic patterns 39A and 39B, respectively. Overlaid. Further, the image 20aP of the concave portion 20a of the image 20P of the phase mark 20 is formed in the opening pattern 39Aa of the periodic pattern 39A, and the image 20bP of the convex portion 20b is formed in the opening pattern 39Ba of the periodic pattern 39B.

  In addition, among the image sensor 38 in FIG. 2A, a plurality of pixels that detect the illumination light IL (actually fluorescence) that has passed through the first periodic pattern 39A on the measurement point Q (i, j). A plurality of pixels that detect the illumination light IL (actually fluorescence) that has passed through the second periodic pattern 39B are referred to as a group 38Aij, and are referred to as a pixel group 38Bij. If the part that processes the detection signals of the pixel groups 38Aij and 38Bij in FIG. 4A in the arithmetic unit 6 of FIG. 1 is an arithmetic unit 6Aij, the arithmetic unit 6Aij will calculate the sum of the detection signals from the pixel group 38Aij, The difference from the sum of the detection signals from the group 38Bij is output as the focus signal SFij (i = 1 to I, j = 1 to J) for each measurement point Q (i, j).

  As described with reference to FIG. 3C, when the formation surfaces (measurement surfaces) of the periodic patterns 39A and 39B are at the best focus position of the projection optical system PL, the light amounts in the opening patterns 39Aa and 39Ba are the same. Yes, the focus signal SFij is zero. On the other hand, when the measurement surface is shifted upward from the best focus position, the light amount in the opening pattern 39Ba is decreased, and when the measurement surface is shifted downward from the best focus position, the light amount in the opening pattern 39Aa is decreased. Therefore, as shown in FIG. 4B, the focus signal SFij changes substantially in proportion to the defocus amount ΔZij, particularly in a range where the defocus amount ΔZij from the best focus position on the measurement surface is small. A focus signal SFij is detected at each of the measurement points Q (i, j) in FIG. Therefore, the focus calculation unit in the calculation device 6 calculates the defocus amount ΔZij from the focus signals SFij output from all the calculation units 6Aij. In this case, the position obtained by correcting the measurement surface by the defocus amount ΔZij is the best focus position at the corresponding measurement point Q (i, j).

  Next, an example of the measurement operation and exposure operation of the optical characteristics of the projection optical system PL in the exposure apparatus EX of the present embodiment will be described with reference to the flowchart of FIG. This operation is executed periodically, for example, during the exposure process under the control of the main control system 2. First, in step 102 in FIG. 5, the reticle stage RST is driven, and as shown in FIG. 2A, the phase mark 20 at each measurement point P (i, j) on the reticle mark plate RFM is placed in the illumination area 18R. Moved. At this time, alignment marks FM1 and FM2 are detected by an aerial image measurement system (not shown) of wafer stage WST, thereby aligning reticle mark plate RFM. In the next step 104, the wafer stage WST is driven, and the measurement point Q (i, j) corresponding to the imaging unit 32 at the position of the image of the phase mark 20 at each measurement point P (i, j) in the exposure area 18W. ) Periodic patterns 39A and 39B. At this time, assuming that the Z coordinate of the best focus position of the projection optical system PL on the optical axis AX so far is 0, the upper surface of the fluorescent film 35 of the imaging unit 32 (the measurement surface on which the periodic patterns 39A and 39B are formed). ) Is set parallel to the XY plane at a position of Z = 0 on the coordinate system (X, Y, Z) as an example.

  In the next step 106, at each measurement point Q (i, j), the detection light DL (fluorescence) generated by the fluorescent film 35 by the illumination light IL that has passed through the periodic patterns 39A and 39B, respectively, is imaged through the FOP 37. Lead to 38. In the next step 108, detection signals of a plurality of pixel groups of the image sensor 38 are input to the arithmetic unit 6Aij, and a focus signal SFij corresponding to the difference in the amount of light passing through the periodic patterns 39A and 39B is detected. In the next step 110, the focus calculation unit in the calculation device 6 obtains the defocus amount ΔZij (and hence the best focus position) from the focus signal SFij at each measurement point Q (i, j). Further, the focus calculation unit uses the defocus amount ΔZij of each measurement point Q (i, j) to form a curved surface (actually connecting the best focus positions of the images of the phase marks 20 on the reticle mark plate RFM by the least square method) Image plane) on the coordinate system (X, Y, Z) of the primary approximate plane IPA (see FIG. 4C), the Z-axis offset Zof, the tilt angle Tx (rad) in the θy direction, and the θx direction The tilt angle Ty (rad) is calculated and stored. Using these parameters, the primary approximate plane is expressed as follows.

Z = Zof−Tx · X−Ty · Y (2)
In the next step 112, the reticle R is loaded on the reticle stage RST, and this alignment is performed. In the next step 114, an unexposed wafer (referred to as wafer W) is loaded on wafer stage WST, and this alignment is performed. In the next step 116, the exposure apparatus EX scans and exposes the pattern image of the reticle R on each shot area SA of the wafer W. At this time, the focus leveling mechanism in the Z tilt stage 22 is driven so that the area in the exposure area 18W on the surface of the wafer W is in contact with the approximate image plane defined by Expression (2). Thereby, the pattern image of the reticle R is exposed to each shot area of the wafer W with high resolution.

  When the tilt level Ty is corrected so that the measurement values of the laser interferometers 28YA and 28YB in FIG. 1 do not change when the focus leveling mechanism is driven according to the equation (2), the irradiation point of the measurement beam of the Z tilt stage 22 is corrected. The Z position of the exposure area 18W changes by Ty · LY using the Y-direction interval LY between the exposure area 18W and the center of the exposure area 18W. In this case, the Z position of the wafer W may be corrected so as to cancel the change in the Z position. The same applies to the tilt angle Tx. In the next step 118, the wafer W is unloaded, and in the next step 120, the exposures in steps 114 to 118 are repeated until there is no exposure target wafer.

Effects and the like of this embodiment are as follows.
(1) The measuring device of the exposure apparatus EX of the present embodiment measures the optical characteristics of the projection optical system PL that forms an image of the pattern of the object surface (first surface) on the image surface (second surface). , A reticle mark plate RFM (first pattern forming member) on which a plurality of phase marks 20 (first patterns) arranged at a plurality of measurement points P (i, j) on the object plane are formed, and measurement of an image plane Fluorescent film 35 (second pattern forming member) on which a plurality of periodic patterns 39A and 39B (second pattern) arranged at a plurality of measurement points Q (i, j) corresponding to the point P (i, j) are formed. And FOP 37 (light guide member) for guiding the detection light DL generated by the illumination light IL that has passed through the phase mark 20, the projection optical system PL, and the periodic patterns 39A and 39B to the detection surface, and the detection surface. It has multiple pixels and detects the detection light DL An imaging element 38, and a computing device for determining the defocus amount (focus position information) and the like at each measurement point by processing a detection signal of the image pickup device 38 Q (i, j).

Moreover, the measuring method using the measuring apparatus calculates | requires the defocus amount etc. of the projection optical system PL by the process of steps 102-110.
According to the present embodiment, the image by the projection optical system PL of the phase mark 20 at a plurality of measurement points is collectively detected by the image sensor 38 via the periodic patterns 39A, 39B and the FOP 37 at the corresponding measurement points. . Thus, by passing through the FOP 37, disturbance light having a large incident angle and light from an image at a distant position can be excluded, and light that has passed through the periodic patterns 39A and 39B can be detected with a high SN ratio. Furthermore, since the formation surface (measurement surface) of the periodic patterns 39A and 39B can be separated from the detection surface 38a of the image sensor 38, the influence of heat generated by the image sensor 38 is reduced. Therefore, the imaging unit 32 can be configured as a small device without increasing the size of the measurement optical system, and the optical characteristics of the entire exposure area 18W of the projection optical system PL can be efficiently and accurately integrated. It can be measured.

  The case where the predetermined pattern is arranged at the measurement point P (i, j) means that the center of the predetermined pattern other than the case where the center of the predetermined pattern is substantially at the measurement point P (i, j). Even if the measurement point P (i, j) is away from the measurement point P (i, j), the optical characteristic measured at the image position of the predetermined pattern is the optical characteristic measured at the measurement point P (i, j). The case where it can be considered that it is substantially the same is also included.

  (2) Further, since the periodic pattern 39 is formed on the fluorescent film 35 and the fluorescence in the visible range generated in the fluorescent film 35 is incident on the FOP 37 through the wavelength selection film 36, the illumination light IL is ultraviolet light. Even if it exists, the optical characteristic of projection optical system PL can be measured using FOP37 which transmits visible light. When the FOP 37 can transmit ultraviolet light with high efficiency, the fluorescent film 35 and the wavelength selection film 36 can be omitted.

(3) Further, the exposure apparatus EX or the exposure method of the present embodiment uses the measurement apparatus or the measurement method of the present embodiment in the exposure apparatus or the exposure method that exposes the pattern on the wafer W via the projection optical system PL. The optical characteristics of the projection optical system PL are measured.
In this case, since the small imaging unit 32 constituting the measuring apparatus can be easily incorporated into the wafer stage WST, the optical characteristics at all the measurement points in the exposure area 18W can be collectively measured with high accuracy. . Therefore, the pattern image of the reticle R can be exposed on the wafer W with high accuracy by controlling the Z position and the tilt angle of the wafer W according to the measurement result.

The imaging unit 32 may be fixed to a measurement stage (not shown) that moves on the upper surface of the wafer base 26 independently of the wafer stage WST.
Further, a test reticle having a phase mark 20 (evaluation mark) may be used instead of the reticle mark plate RFM. In this case, when measuring the optical characteristics of the projection optical system PL, a test reticle is placed on the reticle stage RST instead of the reticle R.

  In the above embodiment, the primary approximate plane IPA (see FIG. 4C) that approximates the image plane of the projection optical system PL is obtained. However, as shown in FIG. 6, by using the imaging unit 32, the best focus position at a plurality of measurement points Q (i, j) on the exposure area side of the projection optical system PL is obtained, and the minimum focus position is determined from these best focus positions. An image plane IP composed of an approximate spherical surface may be obtained by multiplication. In this case, the field curvature can be corrected with high accuracy by driving the lenses L1, L2, etc. of the projection optical system PL using the characteristic control mechanism of FIG. 1 so as to correct the field curvature of the image plane IP. .

  Next, as shown in an enlarged view in FIG. 7A, pitches P1, P2, and P3 (P2 <P1 <P3) that are different in the X direction in the vicinity of each measurement point P (i, j) of the reticle mark plate RFM. ) Phase marks 20, 20A, 20B may be formed. In this case, in the vicinity of the corresponding measurement point Q (i, j) on the upper surface of the fluorescent film 35 of the imaging unit 32, as shown in FIG. 7B, two periodic patterns for detecting the image of the phase mark 20 are detected. 39A, 39B, two periodic patterns 39C, 39D of the pitch β · P2 in the X direction for detecting the image of the phase mark 20A, and two periodic patterns 39E of the pitch β · P3 in the X direction for detecting the image of the phase mark 20B. , 39F are formed in advance. Then, the defocus amount of the image of the phase mark 20A is measured from the difference in the sum of the detection signals of the pixel groups of the image sensor 38 below the periodic patterns 39C and 39D, and the image sensor 38 below the periodic patterns 39E and 39F. The defocus amount of the image of the phase mark 20B is measured from the difference in the sum of the detection signals of the pixel group.

  As shown in FIG. 7C, when the phase marks 20, 20A, 20B are illuminated with the illumination light IL, the opening angles of the illumination lights IL1, IL2, IL3 emitted from the phase marks 20, 20A, 20B are set to illumination light. It becomes larger in the order of IL3, IL1, and IL2. Therefore, the spherical aberration of the projection optical system PL can be obtained from ΔZS, which is the fluctuation range of the defocus amount obtained for each of the illumination lights IL1 to IL3. This spherical aberration can also be corrected by driving a predetermined lens of the projection optical system PL using the characteristic control mechanism of FIG.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the present invention is applied to an exposure apparatus that performs exposure by a liquid immersion method. In FIG. 8, portions corresponding to those in FIG. 1 and FIG. Description is omitted.
FIG. 8 shows a state in which the optical characteristics of the projection optical system PL of the exposure apparatus of the present embodiment are being measured. In FIG. 8, the pattern surface of the reticle mark plate RFM is disposed on the object plane of the projection optical system PL, and the period of the imaging unit 32 provided on the Z tilt stage 22 (wafer stage WST) on the image plane side of the projection optical system PL. The formation surface (measurement surface) of the pattern 39 is arranged. Further, in the immersion space surrounded by the frame-like nozzle head 43 between the lower end portion of the projection optical system PL and the upper surface (protective film 34) of the imaging unit 32, the liquid supply device 41A is used in the same manner as during exposure. A liquid Lq such as pure water that transmits the illumination light IL is supplied through the pipe 42A and the supply port 43a. The liquid Lq in the immersion space is recovered by the liquid recovery device 41B via the filter member 45, the discharge port 43b, and the pipe 42B. The controller 46 controls the temperature and flow rate of the liquid Lq supplied from the liquid supply device 41A. As the local liquid immersion mechanism including the liquid supply device 41A and the like, for example, a mechanism disclosed in US Patent Application Publication No. 2007/242247 or European Patent Application Publication No. 1420298 can be used.

A temperature sensor 44 that measures the temperature of the liquid Lq is fixed inside the nozzle head 43, and the measurement value of the temperature sensor 44 is supplied to the arithmetic device 6 and the control unit 46.
In the present embodiment, when measuring the optical characteristics of the projection optical system PL, as an example, the temperature of the liquid Lq is set to T1, and the arithmetic device 6 processes the detection signal of the imaging element 38 of the imaging unit 32. Then, the defocus amount for each measurement point Q (i, j) is obtained, and the offset Zof of the first-order approximate plane IPA (see FIG. 4C) of Equation (2) by the least square method from these defocus amounts, and The tilt angles Tx and Ty are obtained. Next, the temperature of the liquid Lq is gradually set to values T2, T3,... That differ by ΔT, and similarly, the offset Zof and the tilt angles Tx, Ty of the primary approximate plane IPA of the image plane are obtained.

After that, the focus calculation unit in the calculation device 6 uses the coefficients Az, Atx, Aty and the coefficients for calculating the offset Zof and the tilt angles Tx, Ty of the primary approximation plane IPA as follows as a function of the temperature Tim of the liquid Lq. The values of Bz, Btx, Bty are determined.
Zof = Az · Tim + Bz (3A)
Tx = Atx · Tim + Btx (3B)
Ty = Aty · Tim + Bty (3C)
Thereafter, when the wafer is exposed using the liquid immersion method, the arithmetic unit 6 takes in the temperature Tim of the liquid measured by the temperature sensor 44. As a plane that approximates the image plane in step 116 in FIG. 5, a plane that is determined by the offset Zof and the tilt angles Tx and Ty calculated from the equations (3A) to (3C) is used. Thereby, even if the temperature of the liquid Lq varies, the focusing accuracy of the wafer surface with respect to the image plane of the projection optical system PL can be improved.

Note that, for example, the curvature of field of the projection optical system PL may be measured while changing the temperature of the liquid Lq, and the temperature Tim of the liquid Lq may be set so as to minimize the curvature of field.
Also, if foreign matter such as fine bubbles or resist residue is mixed in the liquid Lq between the projection optical system PL and the imaging unit 32 in FIG. 8, the optical characteristics at the corresponding measurement point Q (i, j). Since the value of (defocus amount ΔZij here) is an abnormal value that deviates significantly from the average value, it is preferable to exclude the abnormal value. For this purpose, the singular point that is the measurement point Q (i, j) at which the measurement value becomes an abnormal value may be determined as follows.

  (1) Dynamic singularity discrimination. A dynamic singular point is a case where a measurement value at a certain measurement point Q (i, j) becomes an abnormal value only at a certain measurement time. For example, it is assumed that the measurement value of the defocus amount at a certain measurement point Q (i, j) changes as shown in FIG. In FIG. 9A, the horizontal axis indicates n-th measurement (n = 1, 2,...), And the vertical axis indicates, for example, the best focus position on the optical axis from the measured defocus amount. The focus position Zij (nm) corrected by subtraction. In this case, FIG. 9B shows a focus position Zij obtained by subtracting the average value Av of the measured values up to n times in FIG. 9A from the focus position Zij. In FIG. 9B, a predetermined threshold value Vth is provided at the focus position Zij, and when the value of the focus position Zij is greater than or equal to Vth / 2 or less than or equal to −Vth / 2, the measured value is regarded as an abnormal value EV. Thus, the measurement value of the measurement point Q (i, j) regarded as the abnormal value EV may be excluded from the data for calculating the approximate plane of the equation (2), for example. Thereby, the influence of an abnormal value can be suppressed.

  (2) Static singularity discrimination. A static singular point is a case in which only a measurement value at a certain measurement point among all measurement points Q (i, j) becomes an abnormal value. For example, when the primary approximate plane IPA shown in FIG. 4C is obtained from the defocus amounts of all measurement points Q (i, j), the defocus amount ΔZij of each measurement point Q (i, j) and the primary approximate planes. A distance from the IPA is calculated, and a measurement point at which the distance is equal to or greater than a predetermined threshold is regarded as a static singular point. In this case, the primary approximate plane IPA may be obtained by excluding the measurement values at the measurement points regarded as singular points. Thereby, the influence of an abnormal value can be suppressed.

When a singular point is detected in this way, it is determined that a foreign substance is mixed in the liquid Lq, and the measurement is performed again using the imaging unit 32 after replacing the liquid Lq, for example. Also good.
[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the present invention is applied when measuring distortion of the projection optical system PL. FIGS. 10 (A) to 13 (C) are shown in FIGS. 2 (A) to 4 (C). Corresponding portions are denoted by the same reference numerals and detailed description thereof is omitted.

  FIG. 10A shows a state in which the optical characteristics of the projection optical system PL of the exposure apparatus of this embodiment are being measured. In FIG. 10A, the pattern surface of the reticle mark plate RFM is arranged on the object plane of the projection optical system PL, the fluorescent film 35 of the imaging unit 32A is arranged on the image plane side of the projection optical system PL, and A plurality of detection patterns are formed. The imaging unit 32A of this embodiment differs from the imaging unit 32 of FIG. 2A only in the detection pattern.

  As shown in FIG. 10B, a phase mark 20 is formed at each measurement point P (i, j) in the illumination area 18R of the reticle mark plate RFM, and in the vicinity of the measurement point P (i, j). In addition, first and second slit marks 51 and 52 are formed close to the phase mark 20. As shown in FIG. 11, the first slit mark 51 is formed by forming two slits 51A and 51B elongated in the X direction in the light shielding film at a predetermined interval in the Y direction (measurement direction). The second slit mark 52 is formed by forming two slits 52A and 52B elongated in the Y direction in the light shielding film at predetermined intervals in the X direction (measurement direction).

  As shown in FIG. 10C, a periodic pattern 39 is formed at each measurement point Q (i, j) in the exposure region 18W on the fluorescent film 35 of the imaging unit 32A, and the measurement point Q (i, In the vicinity of j), first and second wedge-shaped patterns 53 and 54 that are asymmetric in the measurement direction are formed at positions optically conjugate with the slit marks 51 and 52 of FIG. In the following, description of the phase mark 20 and the periodic pattern 39 is omitted.

  As shown in FIG. 12 in which the region including the measurement point Q (i, j) in FIG. 10C is enlarged, the first wedge pattern 53 is formed with a triangular opening pattern 53Aa having a long bottom in the light shielding film. The first pattern 53A and the second pattern 53B in which the opening pattern 53Ba having a shape symmetrical to the opening pattern 53Aa is formed in the light shielding film are arranged side by side in the Y direction. The lengths in the X direction of the patterns 53A and 53B are substantially the same as the lengths of the images 51AP and 51BP of the slits 51A and 51B in FIG. 11, and the interval in the Y direction at the center of the width in the Y direction of the opening patterns 53Aa and 53Ba is , The distance between the centers of the images 51AP and 51BP in the Y direction is the same. Furthermore, the widths of the opening patterns 53Aa and 53Ba in the Y direction are such that even if the positions of the images 51AP and 51BP fluctuate in the Y direction due to distortion of the projection optical system PL, some of the images 51AP and 51BP are within the opening patterns 53Aa and 53Ba. Is set to fit. For example, the width in the Y direction of the images 51AP and 51BP is about several μm to 20 μm, and the height in the Y direction of the opening patterns 53Aa and 53Ba is about two to several times the width of the images 51AP and 51BP.

  Similarly, the second wedge-shaped pattern 54 has a shape obtained by rotating the first wedge-shaped pattern 53 by 90 °, and the second wedge-shaped pattern 54 has an opening that is the same as the first pattern 54A in which the opening pattern 54Aa is formed. The second pattern 54B on which the pattern 54Ba is formed is arranged in the X direction. Even if the positions of the images 52AP and 52BP of the slits 52A and 52B in FIG. 11 fluctuate in the X direction due to the distortion of the projection optical system PL, at least a part of the images 52AP and 52BP is accommodated in the aperture patterns 54Aa and 54Ba. The configuration and operation of the phase mark 20 in FIG. 11 and the periodic pattern 39 in FIG. 12 are the same as those in the first embodiment.

  Also, among the image sensor 38 in FIG. 10A, a plurality of pixels for detecting the illumination light IL (actually fluorescence) that has passed through the patterns 53A and 53B of the first wedge-shaped pattern 53 in FIG. A plurality of pixels that detect the illumination light IL (actually fluorescence) that has passed through the patterns 54A and 54B of the second wedge-shaped pattern 54 are referred to as pixel groups 38Iij and 38Jij. Further, in the same arithmetic unit as the arithmetic unit 6 of FIG. 1, the detection signal of the pixel groups 38Iij and 38Jij is processed with the part that processes the detection signals of the pixel groups 38Gij and 38Hij in FIG. 12A as the arithmetic unit 6Dij. Let the part be the arithmetic unit 6Eij. The arithmetic unit 6Dij (6Eij) calculates the difference between the sum of the detection signals from the pixel group 38Hij (38Iij) and the sum of the detection signals from the pixel group 38Gij (38Jij) as a distortion signal for each measurement point Q (i, j). SYij (SXij) (i = 1 to I, j = 1 to J) is output.

  FIG. 13A shows the slit mark 51 in FIG. 11 formed on the wedge-shaped patterns 53 and 54 in the vicinity of the measurement point Q (i, j) in FIG. 12 when there is no distortion of the projection optical system PL. 52 images 51P and 52P are shown. In FIG. 13A, the amount of light passing through the opening patterns 53Aa and 53Ba of the wedge-shaped pattern 53 is the same, so the distortion signal SYij in FIG. When the shift amount DY of the image 51P in the Y direction due to distortion of the projection optical system PL is positive, the light amount of the image 51BP in the opening pattern 53Ba increases and the light amount of the image 51AP in the opening pattern 53Aa The distortion signal SYij increases and the distortion signal SYij increases. On the other hand, when the shift amount DY is negative, the distortion signal SYij decreases, so that the distortion signal SYij changes almost proportionally with respect to the shift amount DY, as shown in FIG.

  Similarly, the distortion signal SXij in FIG. 12 changes substantially in proportion to the shift amount DX in the X direction of the image 52P on the wedge pattern 54 as shown in FIG. 13B. Therefore, the distortion calculation unit in the calculation device obtains the shift amount DX in the X direction of the image 52P of the slit mark 52 and the shift amount DY in the Y direction of the image 51P of the slit mark 51 from the distortion signals SXij and SYij.

FIG. 13C exaggerates the shift amounts DX and DY of the images 51P and 52P of the slit marks 51 and 52 in the vicinity of each measurement point Q (i, j) of the imaging unit 32A. In this way, distortion of an arbitrary characteristic of the projection optical system PL can be obtained from the distribution of the image shift amounts DX and DY in the vicinity of each measurement point Q (i, j).
In this embodiment, slit marks 51 and 52 are formed on the reticle mark plate RFM side, and wedge-shaped patterns 53 and 54 are formed on the imaging unit 32A side. However, in order to measure the distortion of the projection optical system PL, marks similar to the wedge-shaped patterns 53 and 54 are formed on the reticle mark plate RFM side, and patterns similar to the slit marks 51 and 52 are formed on the imaging unit 32A side. You may form.

  In this embodiment, the focus position information of the projection optical system PL can be measured using the phase mark 20 on the measurement point P (i, j) of the reticle mark plate RFM and the periodic pattern 39 of the imaging unit 32A. . In this embodiment, the phase mark 20 on the measurement point P (i, j) of the reticle mark plate RFM may be omitted, and the periodic pattern 39 on the measurement point Q (i, j) may be omitted. Further, also in this embodiment, the slit marks 51 and 52 may be formed on the test reticle.

  Further, when an electronic device (or microdevice) such as a semiconductor device is manufactured using the exposure apparatus or exposure method of the above embodiment, the electronic device has a function / performance design of the electronic device as shown in FIG. Step 221 to be performed, Step 222 to manufacture a reticle (mask) based on this design step, Step 223 to manufacture a substrate (wafer) that is a base material of the device and apply a resist, the exposure apparatus or exposure of the above-described embodiment Substrate processing step 224 including a step of exposing a reticle pattern to a substrate (photosensitive substrate) by a method, a step of developing the exposed substrate, a heating (curing) and etching step of the developed substrate, a device assembly step (dicing step, Including processing processes such as bonding and packaging) And an inspection step 226, etc. each time.

  In other words, the device manufacturing method forms the pattern of the photosensitive layer on the substrate (wafer) using the exposure apparatus or the exposure method of the above-described embodiment, and processes the substrate on which the pattern is formed. (Step 224). At this time, according to the exposure apparatus or the exposure method of the above-described embodiment, the optical characteristics of the projection optical system PL can be efficiently and accurately measured. For example, by correcting the optical characteristics according to the measurement result, Since an image of a reticle pattern can be exposed on a substrate with high accuracy, an electronic device can be manufactured with high accuracy.

Since the imaging unit 32 and the like of the above-described embodiment includes the fluorescent film 35, the imaging unit 32 and the like use EUV exposure that uses extreme ultraviolet light (Extreme Ultraviolet Light) having a wavelength of about 100 nm or less as exposure light. The present invention is also applicable when measuring the optical characteristics of the projection optical system PL (reflection system) of the apparatus.
The present invention is applicable not only to scanning exposure apparatuses but also to measuring optical characteristics of projection optical systems of batch exposure apparatuses such as steppers.

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, The present invention can also be widely applied to various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, a MEMS (Microelectromechanical Systems), or a DNA chip, or an exposure apparatus for manufacturing a mask (reticle or the like) itself.

The present invention can also be applied to the case of measuring the optical characteristics of a projection optical system used in an apparatus other than the exposure apparatus.
In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

  EX ... exposure apparatus, R ... reticle, RFM ... reticle mark plate, RST ... reticle stage, PL ... projection optical system, W ... wafer, WST ... wafer stage, P (i, j) ... measurement point, 2 ... main control system , 6 ... arithmetic unit, 6Aij ... arithmetic unit, 8 ... characteristic control system, 20 ... phase mark, 32, 32A ... imaging unit, 35 ... fluorescent film, 36 ... wavelength selection film, 37 ... FOP (fiber optic plate), 38 ... two-dimensional imaging device, 39 ... periodic pattern, 51, 52 ... slit mark, 53, 54 ... wedge-shaped pattern

Claims (20)

In a measuring device for measuring optical characteristics of a projection optical system that forms an image of a pattern on a first surface on a second surface,
A first pattern forming member formed with a plurality of first patterns arranged at a plurality of measurement points on the first surface;
A second pattern forming member formed with a plurality of second patterns arranged at positions corresponding to the plurality of measurement points on the second surface;
A light guide member formed by bundling a plurality of optical fibers, guiding detection light generated by illumination light that has passed through the plurality of first patterns, the projection optical system, and the plurality of second patterns to a detection surface;
A photoelectric detector having a plurality of pixels arranged on the detection surface and detecting the detection light guided by the light guide member;
A processing device for processing the detection result of the photoelectric detector to determine the optical characteristics;
A measuring device comprising: A fluorescent film that is formed on the incident surface side of the light guide member and emits fluorescence by entering the illumination light that has passed through the second pattern;
A wavelength selection film formed between the fluorescent film and the light guide member and allowing the fluorescence to pass therethrough, wherein the detection light is the fluorescence that has passed through the wavelength selection film. Item 2. The measuring device according to Item 1. Each of the plurality of first patterns includes a periodic phase pattern;
Each of the plurality of second patterns includes a first partial pattern and a second partial pattern that transmit light that forms an image of a first part and a second part of an image different from each other by the projection optical system of the phase pattern,
The measurement apparatus according to claim 1, wherein the processing apparatus obtains focus position information of a plurality of positions of the projection optical system. When the wavelength of the illumination light is λ, using a positive or negative odd number n, the phase difference φ of the phase pattern is
φ = nλ / 4
The measuring device according to claim 3, wherein   The measurement apparatus according to claim 3 or 4, wherein pitches of the phase patterns of the plurality of first patterns are different from each other. Each of the plurality of first patterns includes a slit pattern,
Each of the plurality of second patterns includes an asymmetric pattern in a measurement direction arranged at a position where an image of the slit pattern by the projection optical system is formed,
The measurement apparatus according to claim 1, wherein the processing apparatus obtains distortion information of the projection optical system. A liquid supply device that supplies a liquid that transmits the illumination light to an immersion space including a space between the projection optical system and the second pattern;
A temperature sensor for measuring the temperature of the liquid,
The measurement apparatus according to claim 1, wherein the processing apparatus obtains the optical characteristic in accordance with a temperature of the liquid measured by the temperature sensor. A liquid supply device that supplies a liquid that transmits the illumination light to an immersion space including a space between the projection optical system and the second pattern;
The measurement according to any one of claims 1 to 6, wherein the processing device determines the presence or absence of a foreign substance in the liquid based on the optical characteristics obtained with respect to the plurality of measurement points. apparatus. In a measurement method for measuring optical characteristics of a projection optical system that forms an image of a pattern on a first surface on a second surface,
A first pattern is disposed at each of the plurality of measurement points on the first surface;
Arranging a second pattern at a position corresponding to the plurality of measurement points on the second surface;
A plurality of the first patterns are illuminated with illumination light, and the detection light generated by the illumination light that has passed through the first pattern, the projection optical system, and the second pattern is formed by bundling a plurality of optical fibers. Led to the detection surface through the light guide member
Detecting the detection light guided to the detection surface by the light guide member via a photoelectric detector having a plurality of pixels;
A measurement method characterized in that the optical characteristic is obtained by processing a detection result of the photoelectric detector. When guiding the detection light to the detection surface via the light guide member,
The measurement method according to claim 9, wherein the illumination light passing through the second pattern is passed through a fluorescent film to generate fluorescence as the detection light. Each of the plurality of first patterns includes a periodic phase pattern;
Each of the plurality of second patterns includes a first partial pattern and a second partial pattern that transmit light that forms an image of a first part and a second part of an image different from each other by the projection optical system of the phase pattern,
The measurement method according to claim 9 or 10, wherein focus position information of a plurality of positions of the projection optical system is obtained as the optical characteristic. When the wavelength of the illumination light is λ, using a positive or negative odd number n, the phase difference φ of the phase pattern is
φ = nλ / 4
The measurement method according to claim 11, wherein: The pitch of the phase pattern of the first pattern at the plurality of measurement points is different from each other,
The measurement method according to claim 11, wherein spherical aberration of the projection optical system is obtained as the optical characteristic. Each of the plurality of first patterns includes a slit pattern,
Each of the plurality of second patterns includes a pattern asymmetric in the measurement direction arranged at a position where the image of the slit pattern by the projection optical system is formed,
The measurement method according to claim 9 or 10, wherein distortion information of the projection optical system is obtained as the optical characteristic. When detecting the detection light guided by the light guide member through a photoelectric detector having a plurality of pixels,
Measuring the temperature of the liquid while supplying the liquid that transmits the illumination light to the immersion space including the space between the projection optical system and the second pattern;
The measurement method according to claim 9, wherein the optical characteristic is obtained in correspondence with a temperature of the liquid. When detecting the detection light guided by the light guide member through a photoelectric detector having a plurality of pixels,
Supplying a liquid that transmits the illumination light to an immersion space including a space between the projection optical system and the second pattern;
The measurement method according to claim 9, wherein presence / absence of a foreign substance in the liquid is determined based on the optical characteristics obtained with respect to the plurality of measurement points. In an exposure apparatus that exposes a pattern on an object via a projection optical system,
An exposure apparatus comprising the measurement apparatus according to claim 1 for measuring optical characteristics of the projection optical system. In an exposure method for exposing a pattern on an object via a projection optical system,
An exposure method, comprising: measuring an optical characteristic of the projection optical system using the measurement method according to any one of claims 9 to 16. Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to claim 17;
Processing the substrate on which the pattern is formed. Forming a pattern of a photosensitive layer on a substrate using the exposure method according to claim 18;
Processing the substrate on which the pattern is formed.

Images