JP4798489B2 - Optical characteristic measuring method and apparatus, and exposure apparatus - Google Patents

Description

  The present invention relates to an optical characteristic measurement technique for measuring optical characteristics such as wavefront aberration of a test optical system, and an exposure technique using this optical characteristic measurement technique.

  For example, in a lithography process for manufacturing a semiconductor device, a pattern of a reticle (or a photomask) is transferred to each shot area of a wafer (or a glass plate, etc.) coated with a resist via a projection optical system. An exposure apparatus such as a stepper or a scanning stepper is used. In order to transfer a fine pattern onto a wafer with high accuracy using these exposure apparatuses, it is required that aberration characteristics as optical characteristics of the projection optical system satisfy a predetermined condition. For this purpose, first, it is necessary to accurately measure (evaluate) the aberration of the projection optical system, and various measuring apparatuses have been used conventionally.

For example, in order to measure the wavefront aberration of the projection optical system, a primary image of the aperture pattern is projected through the projection optical system, the light beam from the primary image is divided into a plurality of wavefronts, and a plurality of wavefront-divided plural images are thus obtained. There has been proposed a measuring apparatus that forms secondary images from light beams and photoelectrically detects these secondary images (see, for example, Patent Document 1). In this measuring apparatus, as an example, the wavefront aberration of the projection optical system is obtained based on the amount of lateral shift from a predetermined reference position of a plurality of secondary images.
JP 2002-71514 A

  In order to improve imaging characteristics such as resolution and depth of focus in an exposure apparatus as semiconductor devices and the like become increasingly finer, linearly polarized light or illumination optical system pupil planes are used as exposure illumination light. So-called polarized illumination using light in a predetermined polarization state is used, such as light polarized in a substantially circumferential direction in the ring-shaped region in FIG. In order to accurately calculate (predict) the aberration of the projection optical system when various patterns are exposed using polarized illumination, the polarization state of the illumination light on the entire illumination optical system or the entire pupil plane of the projection optical system in advance It is desirable to measure aberrations by controlling to a predetermined state.

However, the conventional measuring apparatus or exposure apparatus cannot measure the aberration of the projection optical system in consideration of the polarization state of the illumination light.
The present invention has been made in view of such problems, and an object thereof is to enable measurement in consideration of the polarization state of illumination light when measuring optical characteristics of an optical system such as an illumination optical system and a projection optical system. .

A first optical characteristic measuring apparatus according to the present invention is an optical characteristic measuring apparatus that measures optical characteristics of a test optical system, and illuminates the test optical system with illumination light (1, 12); The polarization member (2, 38) that sets the polarization state of the illumination light and the light passing through the test optical system are converted into light having a light amount distribution corresponding to the phase information on the pupil plane of the test optical system. A light receiving system (23, 24) and a photoelectric detector (25) for detecting light converted by the light receiving system, the light receiving system being a plane conjugate with or near the pupil plane of the optical system to be tested A wavefront splitting element (24) for splitting a light beam through the optical system to be tested and a polarizing element (40) arranged in the vicinity of the wavefront splitting element for selecting light in a predetermined polarization state Is.

According to the present invention, the polarization state of the illumination light can be controlled to be different from that during normal use by the polarizing member.
The second optical characteristic measuring apparatus according to the present invention is an optical characteristic measuring apparatus for measuring optical characteristics of a test optical system, and illuminates the test optical system with illumination light (1, 12). A wavefront splitting element (24) for splitting a light beam through the test optical system on a plane conjugate to or near the pupil plane of the test optical system, and a wavefront splitting element arranged near the wavefront splitting element A polarizing element (40) for selecting light in a predetermined polarization state, a wavefront splitting element, and a photoelectric detector (25) for receiving light via the polarizing element are provided. According to the present invention, the polarizing element can receive illumination light having a polarization state different from that during normal use.
A third optical characteristic measuring apparatus according to the present invention is an optical characteristic measuring apparatus that measures the optical characteristics of a test optical system, and illuminates the test optical system with illumination light (1, 12). And a polarization member (2, 38) for setting the polarization state of the illumination light to a plurality of different polarization states, and the light passing through the test optical system corresponds to the phase information on the pupil plane of the test optical system For each of a plurality of polarization states set by the light receiving system (23, 24) for converting light having a light quantity distribution to be detected, a photoelectric detector (25) for detecting light converted by the light receiving system, and the polarizing member And an arithmetic unit (20) for calculating the optical characteristics of the optical system to be detected based on the detection results respectively obtained by the photoelectric detectors. According to the present invention, the polarization state of the illumination light can be controlled to be different from that during normal use by the polarizing member.

  Further, an exposure apparatus according to the present invention holds the photoconductor in an exposure apparatus having an illumination optical system (12) for illuminating the mask and a projection optical system (PL) for transferring the mask pattern onto the photoconductor. Then, the stage (WST) that moves in the two-dimensional plane, and the optical characteristic measuring device (1) of the present invention in which at least one of the illumination optical system and the projection optical system is provided as the test optical system. , 12, 21) and an adjustment mechanism (26, PL) for adjusting at least one of the optical characteristics of the illumination optical system and the projection optical system based on the measurement result of the optical characteristic measurement device. is there.

The optical characteristic measuring method according to the present invention is an optical characteristic measuring method for measuring the optical characteristic of a test optical system, wherein the test optical system is illuminated with illumination light, and the polarization states of the illumination light are different from each other. Set to a plurality of polarization states, convert the light through the test optical system to light having a light amount distribution corresponding to the phase information on the pupil plane of the test optical system, detect the converted light, Based on the respective detection results obtained for each of a plurality of set polarization states, the optical characteristics of the optical system to be detected are calculated . According to the present invention, it is possible to measure the optical characteristics of the test optical system in consideration of the polarization state of the illumination light.

  In addition, although the code | symbol with the parenthesis attached | subjected to the predetermined element of the above this invention respond | corresponds to the member in drawing which shows one Embodiment of this invention, each code | symbol is used for easy understanding of this invention. However, the present invention is not limited to the configuration of the embodiment.

Hereinafter, an example of a preferred 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 100 composed of a scanning stepper of this example. In FIG. 1, an illumination system composed of an exposure light source 1 and an illumination optical system 12 and a reticle (mask) are held. And a reticle stage RST that moves, a projection optical system PL, a wafer stage WST that holds and moves a resist-coated wafer W (photoreceptor), and a computer, and performs overall control of the entire apparatus, and various arithmetic processes The main controller 20 (arithmetic unit) etc. which performs is provided. Here, an ArF excimer laser light source (wavelength 193 nm) is used as the light source 1. The light source 1 includes a KrF excimer laser light source (wavelength 247 nm), an F ₂ laser light source (wavelength 157 nm), a Kr ₂ laser light source (wavelength 146 nm), a harmonic generation light source of a YAG laser, and a solid-state laser (semiconductor laser, etc.). A harmonic generator or the like can also be used. In the light source 1, on / off of the output of the pulsed laser beam LB, pulse energy, oscillation frequency, center wavelength, spectrum width, and the like are controlled based on control information from the main controller 20.

  The illumination optical system 12 includes a beam matching unit (not shown) that transmits the laser beam LB from the light source 1, a polarization control unit 2, a polarization conversion unit 3, an optical integrator (homogenizer) 5, an illumination system aperture stop plate 6, 1 relay lens 8A, fixed reticle blind (field stop) 9A, movable reticle blind 9B, second relay lens 8B, optical path bending mirror M, condenser lens 10 and the like.

  The polarization control unit 2 of this example includes a half-wave plate that can be rotated by the main controller 20 around the optical axis of the illumination optical system 12. The laser beam LB output from the light source 1 is linearly polarized light, and the laser beam LB when entering the polarization conversion unit 3 through the polarization control unit 2 by controlling the rotation angle of the half-wave plate. The polarization direction can be controlled. The polarization conversion unit 3 includes a plurality of polarization optical units (not shown) for setting the distribution of the polarization direction of the incident laser beam LB in the circumferential direction and the like, and the main controller 20 is connected via the drive unit 4. By rotating the polarization conversion unit 3, a predetermined polarization optical unit is installed on the optical path of the laser beam LB. Each polarization optical unit is formed by combining, for example, a plurality of half-wave plates each having a predetermined shape and a fast axis direction and a transmission plate (or an opening through which light passes) that does not change the polarization direction. However, it can be formed using a quarter-wave plate, a polarizing plate, or the like. Various polarization illuminations can be set by the polarization control unit 2 and the polarization conversion unit 3.

  The laser beam LB that has passed through the polarization conversion unit 3 is emitted as illumination light IL for exposure through the optical integrator 5 and one aperture stop in the illumination system aperture stop plate 6. In this example, a fly-eye lens is used as the optical integrator 5, but an internal reflection type integrator (rod integrator) or a diffractive optical element can also be used. The illumination system aperture stop plate 6 is disposed on the pupil plane PIL of the illumination optical system 12, and is a circular aperture stop (σ stop) for normal illumination, an aperture stop for a small coherence factor (small σ), or for annular illumination. An aperture stop for dipole illumination composed of two apertures, an aperture stop for modified illumination composed of openings disposed at a plurality of positions (for example, four locations) oblique to the optical axis, and the like. It is a rotatable disc. The main controller 20 rotates the illumination system aperture stop plate 6 via the drive unit 7 so that an aperture stop corresponding to the selected illumination condition and the like is installed in the optical path of the laser beam LB.

  The illumination light IL that has passed through a predetermined aperture stop in the illumination system aperture stop plate 6 passes through the first relay lens 8A, the reticle blinds 9A and 9B, the second relay lens 8B, the mirror M, the condenser lens 10, and the like. Illumination is performed using a slit-shaped illumination region on the reticle pattern surface (lower surface) on reticle stage RST. Under the illumination light IL, the pattern in the illumination area of the reticle is projected onto the image plane at a projection magnification β (β is 1/4, 1/5, etc.) via the projection optical system PL. The movable reticle blind 9B has a function of opening and closing the illumination area in the scanning direction and a function of limiting the width of the illumination area in the non-scanning direction.

  Since FIG. 1 shows a state in which the wavefront aberration of the projection optical system PL is measured, an evaluation reticle (test reticle) 13 is loaded on the reticle stage RST, and below the projection optical system PL. A wavefront aberration measuring unit 21 (detailed later) is located. During normal exposure, a reticle R on which an original pattern for a device is formed is loaded on a reticle stage RST, and a wafer W coated with a resist is positioned below the projection optical system PL. Projection is performed in a slit-shaped exposure region on one shot region on the wafer W. As the projection optical system PL, a catadioptric system or the like can be used in addition to the refractive system.

  In the projection optical system PL of this example, in order to adjust spherical aberration, distortion, and the like as its imaging characteristics (optical characteristics), positions of a plurality of predetermined lens elements in the projection optical system PL in the optical axis direction, And an imaging characteristic adjusting mechanism including a driving element such as a piezo element for controlling an inclination angle around the X axis and the Y axis. The main controller 20 drives the imaging characteristic adjusting mechanism via the control system 26, so that the imaging characteristics of the projection optical system PL can be maintained within a predetermined allowable range. Since the imaging characteristics change depending on the irradiation energy of the illumination light IL, for example, by controlling the adjustment amount by the imaging characteristic adjustment mechanism according to the monitoring result of the integrated value of the irradiation energy, the fluctuation of the imaging characteristics Is suppressed. In addition, since aberrations such as spherical aberration and distortion can also be expressed by wavefront aberration, in this example, as an example, from the measurement result of wavefront aberration by the measuring device including the light source 1, the illumination optical system 12, and the measuring unit 21, It is assumed that aberration as an imaging characteristic of the projection optical system PL is obtained. Hereinafter, in FIG. 1, the Z-axis is taken in parallel to the optical axis AX of the projection optical system PL, the X-axis is perpendicular to the paper surface of FIG. 1 in the plane perpendicular to the Z-axis, and the Y-axis is parallel to the paper surface of FIG. Take and explain. The scanning direction of reticle R and wafer W during scanning exposure is a direction parallel to the Y axis (Y direction).

  During exposure, the reticle R is attracted and held on the reticle stage RST, and the reticle stage RST moves on the reticle base (not shown) at a constant speed in the Y direction, and in the rotational directions around the X, Y, and Z axes. It is finely moved to correct the synchronization error of the reticle R. The position of reticle stage RST in the XY plane is measured by moving mirror 15R and laser interferometer 16R. Based on the measured values, main controller 20 drives reticle stage RST via a drive mechanism (not shown) such as a linear motor. Control the speed and position of the.

  On the other hand, wafer W is sucked and held via wafer holder 18 on wafer stage WST. Wafer stage WST is driven on wafer base 14 in the X and Y directions, and the focus position (position in the Z direction) of wafer W and measurement unit 21 and the tilt angle (tilt angle) around the X and Y axes. Z leveling drive unit for controlling The position of wafer stage WST in the XY plane is measured by moving mirror 15W and laser interferometer 16W. Based on this measurement value, main controller 20 controls the speed and position of wafer stage WST in the X and Y directions via drive mechanism 17 such as a linear motor.

  In addition, the exposure apparatus 100 in FIG. 1 includes a pair of reticle alignment microscopes (not shown) for measuring the position of the alignment mark on the reticle R, and an off-counter for measuring the position of the alignment mark on the wafer W. It includes an alignment sensor AS of FIA (Field Image Alignment) system in the Axis system, and a reference mark member (not shown) fixed on wafer stage WST and having a predetermined reference mark formed thereon. Further, the exposure apparatus 100 detects a focus position of the surface of the wafer W or the incident surface of the measurement unit 21, and a projection optical system 19A that projects a plurality of slit images, and a light reception that re-images those slit images. An oblique incidence type multi-point autofocus sensor including the optical system 19B is provided. Based on the measurement value of the autofocus sensor, main controller 20 performs Z leveling of wafer stage WST so that the surface of wafer W or the incident surface of measurement unit 21 is focused on the image plane of projection optical system PL. Control the drive.

  At the time of exposure of the wafer W, after aligning the reticle R and the wafer W, an aperture stop corresponding to a predetermined illumination condition is selected by driving the illumination system aperture stop plate 6, and the polarization control unit 2 and the polarization conversion unit 3 is set to a predetermined polarization illumination state (distribution state of the polarization direction of the laser beam in the aperture stop). Thereafter, the irradiation of the illumination light IL is started, the reticle stage RST and the wafer stage WST are driven, and the reticle R and the wafer W are moved synchronously with respect to the projection optical system PL at a projection magnification ratio, and the wafer stage The operation of stepping and moving the wafer W in the X and Y directions by driving the WST is repeated by the step-and-scan method, and the pattern image of the reticle R is sequentially transferred to each shot area on the wafer W.

An example of polarized illumination during this exposure is as follows.
4A shows an example of the polarization state of the illumination light IL on the pupil plane PIL of the illumination optical system 12 of FIG. 1, and in FIG. 4A, an aperture stop for annular illumination is arranged, The polarization direction of the illumination light IL (laser beam LB) in the aperture stop is set to a substantially circumferential direction (so-called azimuth direction). Note that the X axis and the Y axis in the pupil plane PIL of the illumination optical system 12 in FIG. 4A and subsequent figures respectively indicate directions corresponding to the X axis and the Y axis in the image plane of the projection optical system PL in FIG. . In order to make the distribution of the polarization direction substantially the circumferential direction, in the example of FIG. 4A, a pair of regions 31A and 31C separated from the annular opening in the X direction and a pair separated in the Y direction. The illumination light passing through the pair of regions 31A and 31C is linearly polarized in the direction 32Y parallel to the Y axis and divided into four substantially fan-shaped regions composed of the regions 31B and 31D. The illumination light passing through the pair of regions 31B and 31D is linearly polarized light polarized in a direction 32X parallel to the X axis.

  For example, the polarization state of the polarization conversion unit 3 is shown in FIG. 4 with the polarization direction of the laser beam LB passing through the polarization control unit 2 in FIG. 1 as the direction 32Y parallel to the Y axis. The portion corresponding to the regions 31A and 31C in (A) is a transmissive portion that does not change the polarization direction, and the portions corresponding to the regions 31B and 31D rotate the polarization direction by 90 °, so that the direction intersects the X axis at 45 °. It may be formed so as to be a half-wave plate with a fast axis as. By using the polarized illumination of FIG. 4 (A), as shown in the enlarged view on the image plane of the projection optical system PL of FIG. 4 (B), lines arranged in a fine pitch in the X direction and the Y direction. Images 33X and 33Y of an AND space pattern (hereinafter referred to as L & S pattern) are mainly polarized in directions 32Y and 32X parallel to the Y-axis and X-axis, respectively (that is, the longitudinal direction of the image of each line pattern). It is formed with high resolution by the illuminated light.

  It is also possible to set the polarization direction of the illumination light IL substantially in the radial direction (radial) with the optical axis of the illumination optical system 12 as the center. For this purpose, as shown by a broken line in FIG. 4A, the polarization directions of the illumination light passing through the regions 31A and 31C separated in the X direction and the regions 31B and 31D separated in the Y direction are respectively set to the X axis and The directions 34X and 34Y may be parallel to the Y axis. In addition to this, various polarized illuminations can be set.

  In such exposure, in order to always transfer the image of the pattern of the reticle R onto the wafer W with high resolution and faithful transfer, the main controller 20 exemplifies the illumination conditions and the type of pattern of the reticle R (pitch, The fluctuation amount of the imaging characteristics of the projection optical system PL is predicted at a predetermined time interval according to the light amount distribution on the pupil plane of the projection optical system PL obtained from the periodic direction and the integrated value of the irradiation energy of the illumination light IL. Then, the image formation characteristic of the projection optical system PL is adjusted via the control system 26 and the image formation characteristic adjustment mechanism so as to cancel out the fluctuation amount. In this case, the pattern to be transferred varies depending on the reticle R, and the light amount distribution of the imaging light flux on the pupil plane of the projection optical system PL changes according to the pattern. Therefore, in order to accurately predict the fluctuation amount of the imaging characteristics with respect to various patterns, for example, every time the irradiation energy of the illumination light IL is increased by a predetermined amount, the wavefront on almost the entire surface of the pupil of the projection optical system PL. It is desirable to measure the aberration and store the wavefront aberration data in the storage unit of the main controller 20. Thus, when actually exposing a pattern for a device, as an example, the projection optical system PL is calculated from the distribution of the imaging light flux in the pupil obtained by calculation from this pattern and the wavefront aberration data corresponding to this distribution. The change in wavefront aberration can be accurately predicted.

  Further, since polarized illumination is used in this example, when measuring the wavefront aberration, the polarization state of the illumination light on almost the entire pupil surface of the projection optical system PL or a predetermined region of the pupil surface is, for example, linearly polarized light. It is desirable that the predetermined state can be set. Since the pupil plane of the illumination optical system 12 and the pupil plane of the projection optical system PL are conjugate, instead of setting the polarization state of the illumination light on the pupil plane of the projection optical system PL to a predetermined state, the illumination optical system The polarization state of the illumination light on the 12 pupil planes may be set. In the following, an example of an operation of measuring the wavefront aberration of the projection optical system PL using the measurement unit 21 will be described first, and then a method of measuring the wavefront aberration using the setting operation of the polarization state of the illumination light will be described. .

The measurement unit 21 of this example is detachably fixed to the wafer stage WST of the exposure apparatus 100 so that the wavefront aberration of the projection optical system PL can be measured at any time during maintenance or the like. Note that the measurement unit 21 can be detachably fixed to the reticle stage RST, whereby the wavefront aberration of the illumination optical system 12 can be measured.
In FIG. 1, in order to measure the wavefront aberration of the projection optical system PL, a box-shaped member 21a as a housing of the measurement unit 21 is fixed to the concave portion CA of the wafer stage WST by a not-shown clamp member, and is mounted on the reticle stage RST. 1 shows a state in which a reticle 13 for aberration measurement is loaded. In FIG. 1, by driving the wafer stage WST, the incident surface of the measuring unit 21 is moved to the exposure region of the projection optical system PL.

  FIG. 2 is a diagram showing an apparatus configuration for measuring the wavefront aberration of the projection optical system PL in FIG. 1. In FIG. 2, the reticle 13 is illuminated with the illumination light IL. In the reticle 13, a plurality of circular openings 13 a for aberration measurement are formed in a matrix shape in the light shielding film along the X and Y directions (only one of them is shown in the center in FIG. 2). Yes. The central opening 13a is positioned substantially on the optical axis AX of the projection optical system PL. An alignment mark is also formed on the reticle 13 in a predetermined positional relationship with respect to the opening 13a, and the opening 13a can be positioned by detecting the alignment mark.

  The measurement unit 21 disposed below the projection optical system PL includes a sign plate 22 that is mounted on the wafer stage WST at substantially the same height position (Z-direction position) as the surface of the wafer W. The marking plate 22 is made of, for example, a glass substrate, and has a reference plane 22c that is perpendicular to the optical axis AX of the projection optical system PL and thus perpendicular to the optical axis AX1 of a measurement optical system described later. In the reference plane 22c of the marking plate 22, an opening (light transmission part) 22a is formed at the center. An alignment mark (not shown) is also formed with a predetermined positional relationship with the opening 22a. Here, the opening 22a is set larger than the image of the opening 13a of the reticle 13 formed via the projection optical system PL. Further, on the reference plane 22c, a reflective surface is formed in a region excluding the opening 22a and the alignment mark. The reflecting surface is formed by evaporating chromium (Cr) on a glass substrate, for example.

  Further, in the measurement unit 21, light from the image of the opening 13 a of the reticle 13 formed on the image plane via the projection optical system PL passes to the microlens array 24 via the opening 22 a and the collimating lens 23. Incident. The microlens array 24 is an optical element including a large number of microlenses 24a having a positive refracting power in a square shape that are densely arranged in the X direction and the Y direction, respectively. The microlens array 24 is configured, for example, by forming a microlens group by performing an etching process on a parallel flat glass plate.

  Therefore, the light beam incident on the microlens array 24 is two-dimensionally divided by a large number of microlenses 24a, and an image of one opening 13a is formed in the vicinity of the rear focal plane of each microlens 24a. In other words, a large number of images of the opening 13 a are formed in the vicinity of the rear focal plane of the microlens array 24. A large number of images formed in this way are detected by a two-dimensional image sensor 25 comprising a CCD. Detection signals read from a large number of fine pixels arranged in the photoelectric conversion unit of the image sensor 25 are supplied to the main controller 20. As described above, the microlens array 24 forms a large number of secondary images of the opening 13a by wave-dividing light from the primary image of the opening 13a of the test reticle 13 formed on the image plane of the projection optical system PL. Therefore, a wavefront splitting element is configured. Then, a large number of secondary images are photoelectrically detected by the image sensor 25, the detection signal of the image sensor 25 is converted into digital data in the main controller 20, and the misalignment of the many secondary images is performed by a predetermined calculation process. By determining the quantity, the wavefront aberration of the projection optical system PL is determined. The main control device 20 may convert the detection signal into digital data and store it, and the arithmetic processing may be performed by a host computer (not shown) connected to the main control device 20.

  Further, when the numerical aperture NA of the projection optical system PL is increased, among the illumination light emitted from the projection optical system PL and incident on the image sensor 25, a light beam having a large angle with respect to the optical axis AX has a detection signal after photoelectric conversion. Get smaller. Therefore, the detection signal of the illumination light incident on the image sensor 25 may be multiplied by a coefficient that gradually increases with respect to the angle with respect to the optical axis AX when emitted from the projection optical system PL. Thereby, even when the numerical aperture NA of the projection optical system PL is large, the wavefront aberration can be accurately measured.

  In this example, the marking plate 22, the collimating lens 23, the microlens array 24, and the imaging element 25 constitute a measuring optical system for measuring the wavefront aberration of the projection optical system PL, of which the collimating lens 23 and the microlens. The array 24 constitutes a light receiving system that converts light through the projection optical system PL (test optical system) into light having a light amount distribution corresponding to phase information (wavefront aberration information) on the pupil plane PPL. And the member from the marking board 22 to the image pick-up element 25 is accommodated in the box-shaped member 21a (measurement part 21) of FIG. In this example, the light from the collimating lens 23 is directly guided to the microlens array 24. However, as disclosed in Japanese Patent Laid-Open No. 2002-71514, the space between the collimating lens 23 and the microlens array 24 is used. The optical system for measurement may be configured by arranging a relay optical system. In this case, in order to shorten the height of the measurement unit 21 in the Z direction, a plurality of mirrors may be arranged in the middle of the optical path of the measurement light and the optical path may be bent.

  In general, in the exposure apparatus, the numerical aperture NA of the illumination light IL supplied from the illumination optical system 12 is set smaller than the object-side numerical aperture NAp of the projection optical system PL. Therefore, even if the illumination optical system 12 is used to illuminate the opening 13a of the reticle 13, light through the opening 13a enters the projection optical system PL with an insufficient numerical aperture. Therefore, in this example, as shown in FIG. 2, the aperture 13a is illuminated (incoherent illumination) with a numerical aperture NAi (= sin φI) equal to or larger than the object-side numerical aperture NAp (= sin φP) of the projection optical system PL. As shown in FIG. 1, a diffusing plate 38 such as rubbed glass for diffusing a light beam is provided, which is detachably disposed in an optical path between the illumination optical system 12 and the reticle 13. Instead of the diffuser plate 38, a diffractive optical element 39 that diffracts incident light in various directions may be used. Furthermore, a lemon skin plate may be used instead of the diffusion plate 38.

  In this example, as described above, the opening 13a is illuminated with a numerical aperture NAi that is equal to or larger than the object-side numerical aperture NAp of the projection optical system PL. In this case, as shown in FIG. 2, it can be considered that there are a large number of imaging optical systems independent of each other for each micro lens 24a of the micro lens array 24 of the measurement optical system. Each imaging optical system incoherently forms an image of the opening 13a under the influence of a part of wavefront aberration corresponding to the size of each microlens 24a. At this time, the arrangement of the optical system is set so that an image of the opening 13 a is formed at the center of the opening 22 a of the sign plate 22. That is, the opening 22a is set substantially larger than the image of the opening 13a formed through the projection optical system PL.

  FIG. 3 is an enlarged view showing the light receiving surface of the image sensor 25. As shown in FIG. 3, the light condensed by the individual microlenses 24a (assumed to be 5 rows × 5 columns) in FIG. 2 respectively form images (secondary images) ILA, ILB,..., ILY of the openings 13a in FIG. Assuming that the center of light quantity of these images is the imaging position, vectors 51A, 51B,..., 51Y representing displacements from predetermined reference positions 53A, 53B,. Phase information of illumination light on the pupil plane of the projection optical system PL). The main control device 20 in FIG. 2 obtains information on the vectors 51A to 51Y as an example by performing image processing on detection signals from the respective pixels of the image sensor 25, and illumination light that has passed through the projection optical system PL from this information. Is determined. In addition to the vector, main controller 20 may obtain information on the amount of spread of each image ILA to ILY (information on the power of each light beam) in FIG. 3 and use this information as well.

  Specifically, when the wavefront aberration does not remain in the light that has passed through the projection optical system PL, the light intensity centroid position of each image of the opening 13a is formed at each reference position for measurement. When there is no error due to wavefront aberration or the like in the measurement optical system, the measurement reference positions 53A to 53Y in FIG. 3 are set on the optical axis of each microlens 24a of the microlens array 24. Actually, since the wavefront aberration remains in the projection optical system PL and the measurement optical system, the light intensity barycentric position of each image of the opening 13a is displaced from each reference position. Therefore, in this example, as shown in FIG. 2, the wavefront 52 of the illumination light passing through the collimator lens 23 based on the information of the vectors 51A to 51Y corresponding to the positional deviation amounts of the images ILA to ILY in FIG. Is calculated to measure the wavefront aberration of the illumination light on the pupil plane PPL of the projection optical system PL. Spherical aberration, distortion and the like can be obtained from the measured value of the wavefront aberration.

At this time, since the reticle 13 is provided with a plurality of openings 13a, the wafer stage WST is driven in the X direction and the Y direction to sequentially open the openings 22a of the measurement unit 21. The wavefront aberration can also be measured by moving to the position of the image 13a.
In this example, since the image of the opening 13a having a size that can be resolved by the image sensor 25 is formed, it is not necessary to generate the spherical wave by forming the opening 13a as a minimal pinhole. . That is, in this example, the shape of the opening 13a is not limited to a circular shape. In addition, since the transmittance in the optical path from the opening 13a to the image sensor 25 is determined depending on the transmittance of the optical member constituting the measurement optical system, when using a minimal pinhole for the image sensor 25 In comparison, it is possible to provide significantly higher illuminance. The measurement principle of wavefront aberration is also disclosed in JP-A-2002-71514.

Next, various methods for setting the polarization state of the illumination light to a predetermined state when measuring the wavefront aberration using the measurement unit 21 will be described.
First, in the first method, as shown in FIG. 4A, in order to obtain the wavefront aberration when the polarization direction of the illumination light is set to the circumferential direction, the pupil plane of the illumination optical system 12 is subjected to FIG. And, as shown in (B), the polarization direction of the illumination light passing through the substantially fan-shaped regions 31A, 31C and 31B, 31D that are sequentially separated in the X direction and the Y direction, the direction 32Y parallel to the Y axis, and the X axis The wavefront aberration is measured using the measurement unit 21 of FIG. 2 respectively. Thereafter, by combining the two measurement results in the main controller 20, the wavefront aberration in the polarized illumination in FIG. 4A can be obtained. As the synthesis method, either the method of adding at the stage of the vector indicating the wavefront of FIG. 3 or the method of calculating the coefficient of the Zernike polynomial from the wavefront aberration obtained from the vector indicating the wavefront of FIG. (The details will be described later).

  In order to allow illumination light to pass through only the regions 31A, 31C and 31B, 31D, the aperture stop aperture plate 36A and 36B are respectively provided in the illumination system aperture stop plate 6 of FIG. Further, in this method, in order to obtain the wavefront aberration when the polarization direction of the illumination light is set to the radial direction centering on the optical axis, the polarization direction of the illumination light in FIGS. The directions 34X and 34Y may be parallel to the Y axis.

  Further, as in the polarized illumination of FIG. 4A, as shown in FIG. 6A, on the pupil plane of the illumination optical system 12, elliptical regions 35A, 35C, and 35B separated in the X direction and the Y direction. , 35D, the polarization directions may be directions 32Y and 32X parallel to the Y axis and the X axis, respectively. In order to obtain the wavefront aberration in this polarized illumination, elliptical regions 35A, which are sequentially separated in the X direction and the Y direction on the pupil plane of the illumination optical system 12, as shown in FIGS. 6 (B) and (C). The polarization direction of the illumination light passing through 35C, 35B, and 35D is set to directions 32Y and 32X parallel to the Y axis and the X axis, and the wavefront aberration is measured using the measurement unit 21 in FIG. What is necessary is just to synthesize | combine a measurement result in the main controller 20. FIG. Also in this case, the aperture stops 37A and 37B may be provided on the illumination system aperture stop plate 6 of FIG. 1 in order to transmit the illumination light sequentially only in the regions 35A, 35C and 35B, 35D.

  Next, in the second method, the polarization direction of the illumination light is set parallel to the Y axis or the X axis on almost the entire surface in the pupil of the projection optical system PL, and the projection optical system PL is measured using the measurement unit 21 in FIG. Measure wavefront aberration. Therefore, as an example, the illumination system aperture stop plate 6 in FIG. 1 selects an aperture stop for annular illumination or small σ illumination, and the polarization control unit 2 changes the polarization direction of the laser beam LB to the Y axis or the X axis. The diffusing plate 38 (or the diffractive optical element 39 or the like) is disposed in the vicinity of the upper portion of the reticle 13 without using the polarization conversion unit 3 (for example, simply setting it through). In this configuration, the polarization state of the illumination light on the pupil plane PPL of the projection optical system PL is set by the polarization control unit 2 and the diffusion plate 38.

  When an aperture stop for annular illumination is selected in this example, the illumination light IL (laser beam LB) on the pupil plane of the illumination optical system 12 is as shown in FIGS. 7A and 7C. The coherence factor passes through a ring-shaped region 41 inside the circumference PP1 having a coherence factor of 1, and the polarization directions thereof are directions 32Y and 32X parallel to the Y axis and the X axis in FIGS. 7A and 7C, respectively. . In this case, the diffusion plate 38 disposed in the vicinity of the reticle 13 expands the diffusion direction of the illumination light beyond the numerical aperture on the object side of the projection optical system PL, which corresponds to FIGS. 7A and 7C. The polarization direction of the illumination light on the pupil plane of the projection optical system PL is as follows. The directions 32Y and 32X are parallel to the Y axis and the X axis on almost the entire surface of the pupil PP2, as shown in FIGS. Become. Accordingly, in the cases of FIGS. 7B and 7D, the wavefront aberration of the projection optical system PL is sequentially measured using the measurement unit 21, so that the polarization direction of the illumination light is applied to almost the entire pupil of the projection optical system PL. The wavefront aberration can be measured when Y is the Y direction and the X direction, and the measurement result is stored as wavefront aberration data.

  Thereafter, when an arbitrary pattern on a reticle for manufacturing a device is exposed by illuminating with a polarized illumination whose polarization direction is the X direction or the Y direction, an imaging light beam on the pupil plane of the projection optical system PL is exposed from the pattern. Calculate the distribution of. Then, by using the wavefront aberration data obtained by the polarized illumination corresponding to this distribution, it is possible to predict with high accuracy the fluctuation of the wavefront aberration of the projection optical system PL when the pattern is polarized.

  On the other hand, when an aperture stop for small σ illumination is selected in this example, the illumination light IL (laser beam LB) on the pupil plane of the illumination optical system 12 is as shown in FIGS. In addition, the light passes through a small circular region 42, and the polarization directions thereof are directions 32Y and 32X parallel to the Y axis and the X axis in FIGS. 8A and 8C, respectively. In this case, it is desirable to use a diffractive optical element 39 instead of the diffusion plate 38 in order to increase the diffusion angle of the illumination light. By using the diffractive optical element 39, the polarization directions of the illumination light on the pupil plane of the projection optical system PL corresponding to FIGS. 8A and 8C are as shown in FIGS. 8B and 8D, respectively. The directions 32Y and 32X are parallel to the Y axis and the X axis on almost the entire surface of the pupil PP2. Accordingly, in this case as well, by measuring the wavefront aberration of the projection optical system PL using the measurement unit 21, the polarization direction of the illumination light becomes the Y direction and the X direction on almost the entire surface of the pupil of the projection optical system PL. Wavefront aberration can be measured.

  Next, the two measurement results are combined, and the polarization direction of the illumination light is parallel to the Y axis, the X axis, or the Y axis and the X axis (circumferential direction) on almost the entire surface in the pupil of the projection optical system PL. A method for obtaining the wavefront aberration of the projection optical system PL when set to ## EQU2 ## will be described. For this purpose, as an example, in the illumination system aperture stop plate 6 of FIG. 1, an aperture stop for dipole illumination consisting of openings separated in the X direction and the Y direction is sequentially selected, and the polarization direction of the laser beam LB is selected by the polarization control unit 2. Is set parallel to the Y-axis or X-axis, and the diffusing plate 38 (or the diffractive optical element 39 or the like) is disposed in the vicinity of the upper portion of the reticle 13 without using the polarization conversion unit 3 (for example, simply setting it through). To do. Even in this configuration, the polarization control unit 2 and the diffusion plate 38 set the polarization state of the illumination light on the pupil plane PPL of the projection optical system PL.

  In this example, as shown in FIG. 9, the polarization direction of the illumination light is a direction 32Y parallel to the Y axis, and is composed of elliptical regions 35A and 35C separated in the X direction on the pupil plane of the illumination optical system 12. When the aperture stop 37A is selected, the illumination light is polarized in the Y direction by the action of the diffusing plate 38 in approximately two regions facing the X direction in the region obtained by dividing the pupil PP2 of the projection optical system PL into four. Distributed in the state. By using the measurement unit 21 in FIG. 2 in this state, a vector distribution 43B indicating the wavefront is obtained. Thereafter, when an aperture stop 37B composed of elliptical regions 35B and 35D separated in the Y direction on the pupil plane of the illumination optical system 12 is selected, the illumination light is a region obtained by dividing the pupil PP2 of the projection optical system PL into four parts. Are distributed in a state polarized in the Y direction in almost two regions facing each other in the Y direction. In this state, the vector distribution 43D indicating the wavefront is obtained by using the measurement unit 21 of FIG. The region 45A is a bright part through which illumination light passes, and the region 45B is a dark part. Thereafter, by adding the two vector distributions 43B and 43D, a vector distribution 43E corresponding to the wavefront when illumination light polarized in the Y direction passes through almost the entire surface of the pupil PP2 is obtained, and wavefront aberration is obtained from this vector distribution. 43F is required.

In FIG. 9, by setting the polarization direction of the illumination light to the X direction, the wavefront aberration is obtained when the illumination light polarized in the X direction passes through almost the entire surface of the pupil PP2 of the projection optical system PL.
In this example, as shown in FIG. 10, the polarization direction of the illumination light is a direction 32 Y parallel to the Y axis, and for dipole illumination composed of regions separated in the X direction on the pupil plane of the illumination optical system 12. When the aperture stop 37A is selected, as in the case of FIG. 9, the vector distribution 44B showing the wavefronts in approximately two regions facing the X direction in the region obtained by dividing the pupil PP2 of the projection optical system PL into four. Is required. Thereafter, by using the same aperture stop 37A to increase the amount of illumination light, the two regions 45C facing the X direction in the pupil PP2 of the projection optical system PL are equivalent to the case where there is no illumination light due to the saturation of the amount of light. It becomes. For this reason, a vector distribution 44D indicating wavefronts in approximately two regions facing each other in the Y direction in the pupil PP2 is obtained. Thereafter, by adding the two vector distributions 44B and 44D, a vector distribution 44E corresponding to the wavefront when the illumination light polarized in the Y direction passes through almost the entire surface of the pupil PP2 is obtained, and wavefront aberration is obtained from this vector distribution. 44F is required.

Also in FIG. 10, by setting the polarization direction of the illumination light to the X direction, the wavefront aberration is obtained when the illumination light polarized in the X direction passes through almost the entire surface of the pupil PP2 of the projection optical system PL.
Next, the wavefront aberration of the projection optical system PL when the illumination light polarized in the circumferential direction as shown in FIG. 6A is synthesized by combining the two measurement results obtained by orthogonalizing the polarization directions of the illumination light. Ask.

  In this example, as shown in FIG. 11, the polarization direction of the illumination light is a direction 32Y parallel to the Y-axis, and the aperture stop of the dipole illumination consisting of a region separated in the X direction on the pupil plane of the illumination optical system 12 When 37A is selected, the illumination light is polarized in the Y direction by the action of the diffusing plate 38 in approximately two regions opposed to the X direction in the region obtained by dividing the pupil PP2 of the projection optical system PL into four. Distributed by. In this state, the vector distribution 46B indicating the wavefront is obtained by using the measurement unit 21 in FIG. Thereafter, when the polarization direction of the illumination light is set to a direction 32X parallel to the X axis, and the dipole illumination aperture stop 37B consisting of a region separated in the Y direction on the pupil plane of the illumination optical system 12 is selected, the illumination light Is distributed in approximately two regions facing in the Y direction out of the four regions divided by the pupil PP2 of the projection optical system PL in a state of being polarized in the X direction, and a vector distribution 46D indicating a wavefront is obtained. Thereafter, by adding the two vector distributions 46B and 46D, a vector distribution 46E corresponding to a wavefront when illumination light polarized in a substantially circumferential direction passes through a region obtained by dividing substantially the entire surface of the pupil PP2 into four parts is obtained. The wavefront aberration 46F is obtained from this vector distribution.

In FIG. 11, by rotating the polarization direction of the illumination light by 90 °, wavefront aberration is obtained when the illumination light polarized in the radial direction passes through almost the entire surface of the pupil PP2 of the projection optical system PL.
2, only illumination light in a predetermined polarization state, for example, polarized light in a direction rotated around the Z axis at an arbitrary angle from the illumination light IL that has passed through the projection optical system PL. In order to receive light, as indicated by a two-dot chain line, a polarizing plate 40 may be disposed in the vicinity near the top of the microlens array 24 (or the vicinity near the bottom). Further, instead of the polarizing plate 40, a polarizer such as a wire grid or a polarizing beam splitter that covers the entire incident surface of the microlens array 24 may be disposed. Further, the polarizing plate 40 can be rotated by a motor (not shown), and can select light linearly polarized in various directions.

  When the polarizing plate 40 is arranged in this way, as a first detection method, the polarization direction of the illumination light IL set by the polarization control unit 2 in FIG. 1 and the polarization direction transmitted by the polarizing plate 40 are made parallel. At this time, since only the illumination light IL in the polarization direction set by the polarization control unit 2 can be received by the imaging device 25, the wavefront aberration of the projection optical system PL under the polarization illumination can be measured with high accuracy. As a second detection method, the polarization direction that is passed through the polarizing plate 40 may be orthogonal to the polarization direction of the illumination light IL set by the polarization control unit 2 in FIG. In this case, since only the illumination light IL in the polarization direction orthogonal to the polarization direction set by the polarization control unit 2 can be received by the imaging device 25, the polarization of the illumination light IL by passing through the illumination optical system 12 and the projection optical system PL. Changes in state can be measured.

  Further, as a third detection method, the polarization state of the illumination light IL that has passed through the illumination system aperture stop plate 6 is determined using the polarization control unit 2 as a quarter wavelength plate without using the polarization conversion unit 3 of FIG. Circularly polarized light, that is, substantially non-polarized light may be used. If the light emitted from the light source 1 is circularly polarized light or random polarized light, the light may be irradiated to the reticle 13 via the illumination optical system 12 as it is. Even in these cases, since the diffusing plate 38 (or the diffractive optical element 39 or the like) is disposed and the polarizing plate 40 is provided, the light beam received by the imaging element 25 is reflected on the pupil of the projection optical system PL. It is a polarization component that is polarized in the X direction or the Y direction on almost the entire surface. Therefore, the wavefront aberration of the projection optical system PL when the illumination light IL is polarized in a predetermined state can be measured with a simple configuration in which the polarizing plate 40 is simply provided in the measurement unit 21.

In the present invention, the wavefront aberration of the projection optical system PL is not limited to a measurement system (so-called Shack-Hartmann sensor) having the measurement unit 21 of FIG. 2 but also a shearing interferometer type measurement system and a point diffraction type measurement system. It can also be applied when measuring.
Next, another example of the embodiment of the present invention will be described with reference to FIG. In this example, a polarization member for setting the polarization state of incident illumination light to a predetermined state is provided on the reticle itself for wavefront aberration evaluation. The reticle of this example can be used, for example, when measuring the wavefront aberration of the projection optical system PL of the exposure apparatus shown in FIG. 1 under the polarization illumination. In this case, the polarization control unit 2 and the polarization conversion unit 3 are not necessarily required. Absent.

  12A is a cross-sectional view of a portion of the reticle 47 (mask) of this example as viewed from the front, and FIG. 12B is a plan view of FIG. 12A. FIG. The X axis and the Y axis respectively correspond to the X axis and the Y axis of the stage coordinate system when the reticle 47 is loaded on the reticle stage RST of FIG. As shown in FIG. 12A, a light shielding film 48 is formed on the pattern surface (lower surface) of a reticle 47 made of a glass substrate, and a plurality of light shielding films 48 similar to the openings 13a of the reticle 13 in FIG. Openings 48a, 48b, 48c, 48d, and 48e are formed. The rotation angles with respect to the Y axis are 0 °, 45 °, 90 °, 135 ° (−45 °), and 0 °, respectively, in the recessed regions centered on the points facing the openings 48a to 48e on the upper surface of the reticle 47. Small polarizing beam splitters 49A, 49B, 49C, 49D, and 49E are embedded. The polarization beam splitters 49 </ b> A to 49 </ b> E may be simply fixed to the upper surface of the reticle 47. Furthermore, the upper surface of the polarizing beam splitter 49E at the right end is a rubbed glass surface 49Ea (diffusion surface). Instead of processing the upper surface of the polarizing beam splitter 49E into a rubbing glass surface, a member in which the same diffuser plate 38 or diffractive optical element 39 as in FIG. 1 is miniaturized may be fixed to the upper surface.

As a result, as shown in FIG. 12 (B), the illumination light incident on the reticle 47 passes through the polarization beam splitters 49A, 49B, 49C, 49D, and 49E, and the openings 48a to 48e in FIG. 12 (A). The illumination light emitted from each of the direction 32Y parallel to the Y axis, the direction 32A inclined 45 ° with respect to the Y axis, the direction 32X parallel to the X axis, the direction 32B inclined 135 ° with respect to the Y axis, and The light is polarized in the direction 32Y parallel to the Y axis. Next, in the exposure apparatus of FIG. 1, for example, the diffusing plate 38 is arranged with the polarization state of the illumination light IL that has passed through the illumination system aperture stop plate 6 as circularly polarized light, and the reticle 47 is placed on the reticle stage RST of FIG. Load it. Then , the apertures 48a to 48d in FIG. 12A are sequentially moved to a position conjugate with the aperture 22a of the measurement unit 21 to measure the wavefront aberration of the projection optical system PL. Thereby, even if the illumination light IL irradiated to the reticle 47 is substantially non-polarized light, unlike the normal use state, the entire surface of the pupil of the projection optical system PL is 0 °, 45 ° with respect to the Y direction. It is possible to measure the wavefront aberration when illumination light polarized in the directions intersecting at degrees of 90, 135, and 135 degrees passes.

  Further, when the diffusing plate 38 (or the diffractive optical element 39) is not provided in the arrangement shown in FIG. 1, the opening 48e facing the polarization beam splitter 49E shown in FIG. By moving to a position conjugated with the lens, the wavefront aberration when the illumination light polarized in the Y direction passes through almost the entire pupil of the projection optical system PL can be measured by the action of the frosted glass surface 49Ea. As described above, even when the exposure apparatus itself does not include the polarization control unit 2 or the polarization conversion unit 3, the use of the reticle 47 facilitates wavefront aberration of the projection optical system PL under various polarized illuminations. Can be measured.

  Note that the number and arrangement of the openings 48a to 48e (and the polarization beam splitters 49A to 49E) of the reticle 47 are arbitrary, and they may be arranged in a matrix, for example. In addition to the polarizing beam splitters 49A to 49E, a polarizing plate, an optical rotator that rotates the polarization direction of incident light, or a polarizing plate can be used as the polarizing member fixed or formed on the upper surface of the reticle 47. Furthermore, you may use the member which combined these diffusing plates, an optical rotator, a polarizing plate, and a polarizing beam splitter. Furthermore, the light exposure film 48 and the openings 48a to 48e on the pattern surface of the reticle 47 may be omitted to form a normal exposure device pattern. In this case, polarized illumination can be performed while locally changing the polarization state.

By simply transmitting the polarization beam splitter and the reticle without forming the light shielding film 48, that is, the plurality of openings, on the reticle 47, the polarization state of the illumination light IL set by the illumination optical system 12 is affected. It is possible to measure the polarization state of the illumination light IL that has passed through the projection optical system PL. In this case, the frosted glass surface 49Ea, the diffusion plate 38, and the diffractive optical element 39 are not necessarily provided.
When performing this measurement, the micro lens array 24 may be removed from the optical path of the illumination light by disposing the polarizing plate 40 in the measurement unit 21 of FIG.
In addition, instead of the microlens array 24, a λ / 4 plate (phaser) and a polarizer (polarization beam splitter) are sequentially arranged as the measurement unit 21 along the optical axis direction. Then, the light passing through the collimator lens 23 reaches the image sensor 25 after passing through the λ / 4 plate and the polarization beam splitter. Then, a change in the light intensity distribution on the image pickup surface of the image pickup device 25 is detected while rotating the λ / 4 plate around the optical axis, and the polarization state of the illumination light is measured by the rotational phase shift method from the detection result. Good.

  Further, when a semiconductor device is manufactured using the exposure apparatus of the above-described embodiment, the semiconductor device includes a step of designing a function and performance of the device, a step of manufacturing a reticle based on this step, and a wafer from a silicon material. Forming, aligning with the projection exposure apparatus of the above embodiment to expose the pattern of the reticle onto the wafer, forming a circuit pattern such as etching, device assembly step (dicing process, bonding process, packaging process) Including) and an inspection step.

  The present invention can also be applied to the case where the imaging characteristics of the projection optical system are measured with an immersion type exposure apparatus disclosed in, for example, International Publication No. 99/49504 pamphlet. 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, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD, etc.), micromachine, thin film magnetic head, and DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process. As described above, the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be taken without departing from the gist of the present invention.

  By applying the present invention to an exposure apparatus, it is possible to measure the imaging characteristics of the projection optical system under polarized illumination with high accuracy. Therefore, by correcting the imaging characteristics of the projection optical system using the result, a fine pattern can be manufactured with high accuracy using polarized illumination.

1 is a partially cutaway view showing a schematic configuration of an exposure apparatus as an example of an embodiment of the present invention. It is a figure which shows the apparatus structure for the wavefront aberration measurement with respect to the projection optical system PL in FIG. FIG. 3 is an enlarged plan view showing a number of secondary images formed on the light receiving surface of the image sensor 25 of FIG. 2. (A) is a figure which shows an example of the aperture stop in the case of using the illumination light polarized in the circumferential direction or radial direction, (B) is an enlarged view which shows an example of the pattern exposed with high precision by polarized illumination. (A) is a diagram showing an aperture stop having a pair of openings separated in the X direction, and (B) is a diagram showing an aperture stop having a pair of openings separated in the Y direction. (A) is a diagram showing another example of an aperture stop in the case of using illumination light polarized in the circumferential direction, (B) is a diagram showing an aperture stop having a pair of apertures separated in the X direction, (C) It is a figure which shows the aperture stop which has a pair of opening apart in the Y direction. (A) is a figure which shows an example of the polarization state in the case of using the aperture stop for annular illumination, (B) is a figure which shows the polarization state on the pupil plane of the projection optical system corresponding to FIG. 7 (A), (C) is a diagram showing another example of the polarization state when using an aperture stop for annular illumination, and (D) shows the polarization state on the pupil plane of the projection optical system corresponding to FIG. 7 (C). FIG. (A) is a diagram showing an example of a polarization state when using an aperture stop for small σ illumination, (B) is a diagram showing a polarization state on the pupil plane of the projection optical system corresponding to FIG. 8 (A), (C) is a diagram showing another example of the polarization state when an aperture stop for small σ illumination is used, and (D) shows the polarization state on the pupil plane of the projection optical system corresponding to FIG. 8 (C). FIG. It is explanatory drawing of the operation | movement which calculates | requires the wavefront aberration of the projection optical system under polarization illumination by combining the measurement result of the wavefront aberration of 2 times using a different aperture stop. It is explanatory drawing of the operation | movement which synthesize | combines the measurement result of two wavefront aberrations using different light quantity, and calculates | requires the wavefront aberration of the projection optical system under polarization illumination. It is explanatory drawing of operation | movement which calculates | requires the wavefront aberration of the projection optical system under polarization illumination by combining the measurement result of two times of wavefront aberration using different aperture stops with different polarization illumination. (A) is sectional drawing which shows a part of reticle of the other example of embodiment of this invention, (B) is a top view of FIG. 12 (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Polarization control unit, 3 ... Polarization conversion unit, 6 ... Illumination system aperture stop plate, 12 ... Illumination optical system, 13, 47 ... Reticle for evaluation, R ... Reticle, PL ... Projection optical system, W DESCRIPTION OF SYMBOLS ... Wafer, 20 ... Main controller, 21 ... Measuring part, 22 ... Marking plate, 23 ... Collimating lens, 24 ... Micro fly eye, 25 ... Imaging element, 38 ... Diffusing plate, 39 ... Diffractive optical element, 40 ... Polarizing plate , 49A to 49E ... Polarizing beam splitter

Claims (18)

An optical property measuring device for measuring optical properties of a test optical system,
An illumination system that illuminates the test optical system with illumination light;
A polarizing member for setting the polarization state of the illumination light;
A light receiving system for converting light through the test optical system into light having a light amount distribution corresponding to phase information on a pupil plane of the test optical system;
A photoelectric detector for detecting light converted by the light receiving system;
The light receiving system is disposed in the vicinity of the wavefront splitting element, a wavefront splitting element that splits a light beam through the test optical system on a plane conjugate with or near the pupil plane of the test optical system. An optical characteristic measuring apparatus comprising: a polarizing element that selects light having a predetermined polarization state. Wherein the polarization direction of the illumination light to set the polarization member, the optical property measuring apparatus according to claim 1 in which the polarization direction of the light selected by said polarization element are different from each other. A mask disposed on the object plane of the test optical system;
Wherein at least a portion of the polarization member, the optical property measurement apparatus according to claim 1 or 2, characterized in that provided in the mask. The optical property measuring apparatus according to claim 3 , wherein the member provided on the mask includes at least one of a diffusing element, an optical rotator, a polarizing plate, and a polarizing beam splitter. An optical property measuring device for measuring optical properties of a test optical system,
An illumination system that illuminates the test optical system with illumination light;
A wavefront splitting element that splits a light beam through the test optical system on a plane conjugate to or near the pupil plane of the test optical system;
A polarizing element that is disposed in the vicinity of the wavefront splitting element and selects light having a predetermined polarization state;
An optical characteristic measuring apparatus comprising: a photoelectric detector that receives light via the wavefront splitting element and the polarizing element. A polarizing member for setting a polarization state of the illumination light;
6. The optical characteristic measuring apparatus according to claim 5 , wherein a polarization direction of the illumination light set by the polarizing member is different from a polarization direction of the light selected by the polarizing element. A mask disposed on the object plane of the test optical system;
The optical characteristic measuring apparatus according to claim 6 , wherein at least a part of the polarizing member is provided on the mask. The optical property measuring apparatus according to claim 7 , wherein the member provided on the mask includes at least one of a diffusing element, an optical rotatory element, a polarizing plate, and a polarizing beam splitter. An optical property measuring device for measuring optical properties of a test optical system,
An illumination system that illuminates the test optical system with illumination light;
A polarizing member that sets the polarization state of the illumination light to a plurality of different polarization states ;
A light receiving system for converting light through the test optical system into light having a light amount distribution corresponding to phase information on a pupil plane of the test optical system;
A photoelectric detector for detecting light converted by the light receiving system;
For each of a plurality of polarization states set by the polarizing member, an arithmetic device that calculates the optical characteristics of the optical system to be measured based on detection results obtained by the photoelectric detectors;
An optical characteristic measuring device comprising: The polarizing member includes a polarizing element that sets a polarization direction of the illumination light, and a diffusing element that is disposed in the vicinity of the object plane of the optical system to be measured or a conjugate plane with this surface and diffuses the illumination light. The optical characteristic measuring apparatus according to claim 9 . The optical characteristic measurement apparatus according to claim 10 , wherein the diffusion element is a diffusion plate or a diffractive optical element. The illumination system is capable of illuminating the optical system under test with two-pole illumination in which the amount of light is larger with respect to other regions in two regions away from the optical axis on the pupil plane of the illumination system,
The polarizing member includes a polarizing element that sets a polarization direction of the illumination light, and a diffusing element that is disposed in the vicinity of the object plane of the optical system to be measured or a conjugate plane with this surface and diffuses the illumination light. The optical characteristic measuring apparatus according to claim 9 . A mask disposed on the object plane of the test optical system;
The optical characteristic measuring apparatus according to claim 9 , wherein at least a part of the polarizing member is provided on the mask. The optical property measuring apparatus according to claim 13 , wherein the member provided on the mask includes at least one of a diffusing element, an optical rotatory element, a polarizing plate, and a polarizing beam splitter. The optical characteristic measuring apparatus according to any one of claims 1, wherein the correcting the detection result of the photoelectric detector in accordance with the numerical aperture of the optical system to be measured 14. In an exposure apparatus having an illumination optical system for illuminating a mask and a projection optical system for transferring a pattern of the mask onto a photoconductor,
A stage holding the photoreceptor and moving in a two-dimensional plane;
The optical property measurement apparatus according to any one of claims 1 to 15 , wherein the optical characteristic measurement apparatus is provided on the stage, and at least one of the illumination optical system and the projection optical system is the test optical system.
An exposure apparatus comprising: an adjustment mechanism that adjusts at least one optical characteristic of the illumination optical system and the projection optical system based on a measurement result of the optical characteristic measurement apparatus. An optical property measurement method for measuring optical properties of a test optical system,
Illuminating the test optical system with illumination light,
Setting the polarization state of the illumination light to a plurality of different polarization states ,
Converting light through the test optical system into light having a light amount distribution corresponding to phase information on the pupil plane of the test optical system;
Detecting the converted light;
An optical characteristic measuring method , comprising: calculating optical characteristics of the optical system to be detected based on detection results obtained for each of a plurality of set polarization states . The optical characteristic measurement according to claim 17, wherein when setting the polarization state of the illumination light, the illumination light is diffused in the vicinity of an object plane of the optical system to be measured or a conjugate plane with the object plane. Method.

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