WO2003028073A1

WO2003028073A1 - Aberration measuring device, aberration measuring method, regulation method for optical system, and exposure system provided with optical system regulated by the regulation method

Info

Publication number: WO2003028073A1
Application number: PCT/JP2002/009810
Authority: WO
Inventors: Naomasa Shiraishi
Original assignee: Nikon Corporation
Priority date: 2001-09-26
Filing date: 2002-09-24
Publication date: 2003-04-03
Also published as: TW561254B; JPWO2003028073A1

Abstract

An aberration measuring device capable of very accurately measuring the residual aberration of an optical system caused by the double refraction of an optical member formed of a crystal such as fluorite. An aberration measuring device for measuring the aberration of an optical system (15) including an optical member formed of a crystal belonging to a cubic system. The device comprises light flux irradiation units (1-13) for applying specific light flux to an optical system, and an aberration measuring unit (17) for measuring the aberration of the optical system based on a light flux passed through the optical system. A light flux irradiation unit has a polarization switching means for switching the polarizing condition of a specified light flux between a first linear polarization polarized along a first direction and a second linear polarization polarized along a second direction almost orthogonal to the first direction.

Description

Description Aberration measurement device, Aberration measurement method, Optical system adjustment method,

And exposure apparatus having an optical system adjusted by the adjusting method

The present invention relates to an aberration measurement device, an aberration measurement method, an adjustment method of an optical system, and an exposure apparatus including an optical system adjusted by the adjustment method. The present invention particularly relates to aberration measurement of a projection optical system mounted on an exposure apparatus used when a micro device such as a semiconductor device or a liquid crystal display device is manufactured by a photolithography process. Background art

When forming micropatterns for electronic devices (microdevices) such as semiconductor integrated circuits and liquid crystal displays, the pattern of the photomask (also referred to as a reticle) drawn by enlarging the pattern to be formed by about 4 to 5 times is projected. A method of performing reduced exposure transfer onto a photosensitive substrate (substrate to be exposed) such as Jehachi using an exposure apparatus is used. In this type of projection exposure apparatus, the exposure wavelength keeps shifting to shorter wavelengths in order to cope with miniaturization of semiconductor integrated circuits.

Currently, the exposure wavelength of the KrF excimer laser is 248 nm, but the shorter wavelength of the ArF excimer laser, 193 nm, is entering the stage of practical use. Furthermore, the A r ₂ laser having a wavelength of 1 5 7 nm of F ₂ laser one and the wavelength 1 2 6 nm, proposed a projection exposure equipment that uses the light source for supplying light in a wavelength band so-called vacuum ultraviolet region Is being done. In addition, since high resolution can be achieved by increasing the numerical aperture (NA) of the projection optical system, not only development of a shorter exposure wavelength but also development of a projection optical system with a larger numerical aperture Has also been made.

In this case, a smaller exposure field of view (exposure field) of the projection optical system is advantageous for increasing the NA of the optical system. Therefore, the field of view of the projection optical system itself is reduced, and instead, the reticle and the wafer are relatively scanned during exposure to ensure a substantially large field of view. Type exposure apparatus has also been put to practical use. The projection optical systems mounted on these exposure apparatuses are required to have extremely small residual aberrations in order to achieve high resolution. Therefore, in the manufacturing process of the projection optical system, wavefront aberration measurement using light interference is performed, the amount of residual aberration is measured with an accuracy of about 1/1000 of the exposure wavelength, and the projection optical system is evaluated based on the measured value. The system is being adjusted.

To measure such a small amount of aberration, the wavefront aberration that represents the change in the optical path length from one point on the reticle to each point on the wafer through each optical path in the projection optical system and to each point on the wafer Is generally measured. Several methods that apply the principle of interferometers have been put to practical use and have been proposed for measuring wavefront aberration. A Fizeau interferometer using a laser of the same wavelength as the exposure wavelength as the light source has high measurement accuracy and is suitable for measuring the wavefront aberration of the projection optical system. However, the laser as the light source must have a coherent distance (temporal coherence length) in the traveling direction that is larger than the reciprocating distance (2 m) of the optical path of the projection optical system having a length of 1 m or more. It is said.

In the case of a KrF excimer laser with an exposure wavelength of 248 nm, lasers with almost the same wavelength and sufficiently long temporal coherence (eg, harmonics of an argon laser or semiconductors) Laser harmonics) can be used. However, in the case of an ArF excimer laser with an exposure wavelength of 193 nm or an exposure wavelength of 15711111? _In the case of _two lasers, since there is no laser having substantially the same wavelength and sufficiently long temporal coherence, it is necessary to measure the wavefront aberration by another method. Other wavefront aberration measurement methods include, for example, PDI (Point Diffraction Interferoieter), Twyman-Green interferometer, sharing interferometer, etc., and various measurement methods such as Shack-Hartmann method. Has been put into practical use and proposed.

If the exposure wavelength is shortened for higher resolution, optical materials having good transparency to the exposure wavelength are limited. For KrF excimer laser light with a wavelength of 248 nm, synthetic quartz glass and fluorite (calcium fluoride crystal) can be used as transmissive optical materials. However, for ArF excimer laser light with a wavelength of 193 nm, quartz has a compaction problem, so it is necessary to increase the composition ratio of optical members using fluorite (such as fluorite lenses). . further, In the case of a single F ₂ laser with a wavelength of 157 nm, the transparency of synthetic quartz glass is poor, and the usable optical materials are practically limited to fluorite.

Fluorite has been considered to be optically isotropic and has no birefringence because its crystal structure is classified as cubic. However, at the 157—Workshop hosted by SE MAT ECH held in May 2001, the NIST in the United States reported the essential birefringence of fluorite, and the wavelength of It was found that fluorite has relatively large birefringence to light. It was also found that cubic crystal materials other than fluorite, such as barium fluoride and strontium fluoride, also have birefringence to such short wavelength light.

However, the amount of this intrinsic birefringence (intr ins icbirefringence) is uniquely determined based on the wavelength of light and the angular relationship between the direction of the crystal lattice and the direction of light propagation in the crystal. It is decided. Therefore, at the stage of optical design, it is possible to predict the amount of birefringence and to compensate for the effect by design. More specifically, the optical axis of each fluorite lens is made to coincide with the predetermined crystal axis of the fluorite crystal, and each fluorite lens is oriented so that another predetermined crystal axis is oriented in a predetermined direction. By arranging them around a predetermined angle around them, it is possible to offset the adverse effects of fluorite on birefringence. However, even if the aberration caused by the birefringence of fluorite is almost completely corrected by design by the above-mentioned method, the manufacturing error of each fluorite lens and each fluorite Due to lens positioning errors (mounting errors), aberrations due to birefringence of fluorite may remain. Disclosure of the invention

The present invention has been made in view of the above-mentioned problems, and is capable of measuring, with high accuracy, residual aberration of an optical system caused by, for example, birefringence of an optical member formed of a crystal such as fluorite. It is an object to provide a measuring device and an aberration measuring method. In addition, based on the aberration result measured with high accuracy using the aberration measuring device and the aberration measuring method of the present invention, the adjustment of the optical system capable of favorably removing the residual aberration of the optical system caused by the birefringence. The aim is to provide a method. It is a further object of the present invention to provide an exposure apparatus having an optical system having good optical performance, which has been optically adjusted using the adjustment method of the present invention.

Another object of the present invention is to provide a microdevice manufacturing method capable of manufacturing a high-performance microdevice according to a high-resolution exposure technology using an exposure apparatus equipped with an optical system having good optical performance. Aim.

According to a first aspect of the present invention, there is provided an aberration measuring apparatus for measuring an aberration of an optical system including an optical member formed of a crystal belonging to a cubic system. A light beam irradiation unit for irradiating the light beam;

An aberration measurement unit for measuring aberration of the optical system based on a light beam transmitted through the optical system,

The light beam irradiation unit includes a first linearly polarized light polarized along a first direction and a second linearly polarized light polarized along a second direction different from the first direction, There is provided an aberration measuring device characterized by having a polarization switching means for switching the polarization state of the predetermined light flux.

According to a preferred aspect of the first invention, the aberration measurement unit includes: a first aberration measurement result measured based on a light beam transmitted through the optical system irradiated with the first linearly polarized light beam; An aberration of the optical system caused by birefringence of the optical member is measured based on a second aberration measurement result measured based on a light beam transmitted through the optical system irradiated with the linearly polarized light beam.

Further, according to a preferred aspect of the first invention, the polarization switching means includes: a linearly polarized light separating means for separating a predetermined linearly polarized light beam polarized along a predetermined direction from an incident light beam; And a polarization plane rotating means for rotating the polarization plane of the predetermined linearly polarized light beam separated via the separation means around a central axis of the predetermined linearly polarized light beam. In this case, it is preferable that the linearly polarized light separating means has a location prism. Further, it is preferable that the polarization plane rotating means has a 1Z2 wavelength plate that can rotate about the central axis. Alternatively, the polarization plane rotating means may include a first quarter-wave plate rotatable about the central axis, and a second quarter-wave plate rotatable about the central axis. Like New

According to a second aspect of the present invention, there is provided an aberration measuring method for measuring an aberration of an optical system including an optical member formed of a crystal belonging to a cubic system,

A first irradiation step of irradiating the optical system with a first linearly polarized light beam polarized along a first direction,

A first aberration measurement step for measuring aberration of the optical system based on a light beam transmitted through the optical system irradiated with the light beam of the first linearly polarized light,

A second irradiation step of irradiating the optical system with a second linearly polarized light beam polarized along a second direction different from the first direction;

A second aberration measurement step for measuring aberration of the optical system based on a light beam transmitted through the optical system irradiated with the light beam of the second linearly polarized light;

Based on the first aberration measurement result obtained in the first aberration measurement step and the second aberration measurement result obtained in the second aberration measurement step, aberration of the optical system caused by birefringence of the optical member And an aberration measuring step of measuring the aberration.

According to a preferred aspect of the first invention and the second invention, the first direction and the second direction are substantially orthogonal to each other. Further, the wavelength of the light beam is preferably 193 nm or 157 ηm.

In the third invention of the present invention, the aberration measurement result of the optical system measured by using the aberration measuring device of the first invention or the aberration measurement result of the optical system measured by using the aberration measurement method of the second invention An optical adjustment step of optically adjusting the optical system in order to substantially remove aberration remaining in the optical system due to birefringence of the optical member based on I do.

According to a preferred aspect of the third invention, the optical adjustment step includes: a clocking step of rotating the optical member around an optical axis of the optical system; and a moving step of moving the optical member along the optical axis. And a tilting step of moving the optical member along a plane substantially perpendicular to the optical axis; and a tilting step of tilting the optical member with respect to the optical axis. According to a fourth aspect of the present invention, there is provided an illumination optical system for illuminating a mask, and an optical system adjusted by an adjustment method of a third aspect for forming an image of a pattern formed on the mask on a photosensitive substrate. The present invention provides an exposure apparatus characterized by comprising a system.

In the fifth invention of the present invention, an exposure step of exposing the pattern of the mask to the photosensitive substrate using the exposure apparatus of the fourth invention, and a development step of developing the photosensitive substrate exposed in the exposure step The present invention provides a method for manufacturing a micro device characterized by including: BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus including a projection optical system to which an aberration measurement apparatus and an aberration measurement method according to an embodiment of the present invention are applied.

FIG. 2 is a diagram schematically showing a configuration of an aberration measuring device according to an embodiment of the present invention.

FIG. 3 is a diagram schematically showing a configuration of a sharing interferometer as the aberration measurement unit of FIG.

FIG. 4 is a diagram schematically showing a configuration of a Schattk-Hartmann sensor as the aberration measurement unit in FIG.

FIG. 5 is a diagram schematically showing a configuration of the polarization control optical system of FIG.

FIG. 6 is a diagram showing a modification in which a pair of quarter-wave plates are used instead of the half-wave plate of FIG.

FIG. 7 is a diagram schematically showing a configuration of a polarization conversion measurement unit for measuring how much polarization conversion is caused by the projection optical system of FIG.

FIG. 8 is a flowchart of a method for obtaining a semiconductor device as a micro device.

FIG. 9 is a flowchart of a method for obtaining a liquid crystal display element as a micro device. BEST MODE FOR CARRYING OUT THE INVENTION

Birefringence means that the refractive index varies depending on the polarization direction of light, that is, the refraction angle and the wavelength of light propagating in a medium (lens) vary depending on the polarization direction of light. In the aberration measurement device and the aberration measurement method of the present invention, each of the aberration measurement of the optical system is performed by using two linearly polarized light beams having different polarization directions, specifically, two linearly polarized light beams having polarization directions orthogonal to each other. The aberration for linearly polarized light is measured independently. In this way, it is possible to respectively measure the wavefront differences experienced by linearly polarized light having polarization planes in directions orthogonal to each other. As a result, the amount of aberration of the optical system due to birefringence can be measured (calculated) as the difference between the aberration measurement values of two linearly polarized lights having polarization directions orthogonal to each other.

When the aberration due to birefringence is obtained by using the aberration measuring apparatus and the aberration measuring method of the present invention, the aberration measurement result, the birefringence characteristics of the optical material such as fluorite, and the design data of the optical member (lens) are obtained. (Eg clocking adjustment to rotate the optical member around the optical axis, movement adjustment to move the optical member along the optical axis, or to make the optical member almost orthogonal to the optical axis) It is possible to estimate whether the effects of birefringence can be eliminated by performing a shift adjustment that moves along the surface to be adjusted or a tilt adjustment that tilts the optical member with respect to the optical axis. As a result, by performing a predetermined optical adjustment to a predetermined optical member based on the estimation result, it becomes possible to remove residual aberration of the optical system caused by birefringence.

An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus including a projection optical system to which an aberration measurement apparatus and an aberration measurement method according to an embodiment of the present invention are applied. In FIG. 1, the Z axis is parallel to the reference optical axis AX of the projection optical system PL, the Y axis is parallel to the plane of FIG. 1 in a plane perpendicular to the reference optical axis AX, and the reference optical axis AX The X axis is set perpendicular to the plane of Fig. 1 in a plane perpendicular to the plane.

The exposure apparatus shown in FIG. 1 as a light source LS for supplying illumination light in the ultraviolet region, F ₂ laser primary light source (wavelength 1 5 7 nm) or A r F excimer laser light source (wavelength 1 9 3 nm) Have. Light emitted from the light source LS passes through the illumination optical system IL. Then, the reticle (mask) R on which the predetermined pattern is formed is uniformly illuminated. The optical path between the light source LS and the illumination optical system IL is sealed with a casing (shown in a tree), and the space from the light source LS to the optical member closest to the reticle side in the illumination optical system IL is exposed to the exposure light. It has been replaced by inert gas such as helium gas or nitrogen, which is a gas with low absorption rate, or is kept almost in vacuum.

The reticle R is held in parallel with the XY plane on the reticle stage RS via a reticle holder RH. A pattern to be transferred is formed on reticle R, and a rectangular pattern area having a long side along the X direction and a short side along the Y direction in the entire pattern area is illuminated. . The reticle stage RS can be moved two-dimensionally along the reticle plane (that is, the XY plane) by the action of a drive system (not shown), and its position coordinates are measured by an interferometer RIF using a reticle moving mirror RM. And the position is controlled.

Light from the pattern formed on the reticle R forms a reticle pattern image on the wafer W as a photosensitive substrate via the projection optical system PL. The wafer W is held in parallel with the XY plane on the wafer stage WS via a wafer table (wafer holder) WT. Then, on the wafer W, a rectangular exposure area having a long side along the X direction and a short side along the Y direction so as to optically correspond to the rectangular illumination area on the reticle R. A pattern image is formed on the substrate. The wafer stage WS can be moved two-dimensionally along the wafer surface (that is, the XY plane) by the action of a drive system (not shown), and its position coordinates are measured by an interferometer WIF using a wafer moving mirror WM. In addition, the position is controlled.

In the illustrated exposure apparatus, the optical member (the lens 15 1 in the present embodiment) disposed closest to the reticle and the optical member disposed closest to the wafer side (in the present embodiment) among the optical members constituting the projection optical system PL. In the present embodiment, the inside of the projection optical system PL is configured to maintain an airtight state with the lens 16 4), and the gas inside the projection optical system PL is replaced with an inert gas such as helium gas or nitrogen. It is kept or almost kept in a vacuum state.

In addition, a narrow optical path between the illumination optical system IL and the projection optical system PL includes a reticle R And a reticle stage RS, etc., are placed. An inert gas such as nitrogen or helium gas is filled inside a casing (not shown) that hermetically surrounds the reticle R and the reticle stage RS. Alternatively, it is kept almost in a vacuum state.

In the narrow optical path between the projection optical system PL and the wafer W, the wafer W and the wafer stage WS are arranged, but a casing (not shown) that hermetically surrounds the wafer W and the wafer stage WS. ) Is filled with an inert gas such as nitrogen or helium gas, or is maintained in a nearly vacuum state. Thus, an atmosphere in which the exposure light is hardly absorbed is formed over the entire optical path from the light source LS to the wafer W.

As described above, the illumination area on the reticle R and the exposure area on the wafer W (that is, the effective exposure area ER) defined by the projection optical system PL are rectangular with short sides along the Y direction. . Therefore, while controlling the position of the reticle R and the wafer W using a drive system and an interferometer (RIF, WIF), the reticle stage RS is moved along the short side direction of the rectangular exposure area and the illumination area, that is, along the Y direction. By moving (scanning) the wafer stage WS and, consequently, the reticle R and the wafer W synchronously, the wafer W has a width equal to the long side of the exposure area and the scanning amount of the wafer W (moving). The reticle pattern is scanned and exposed to a region having a length corresponding to the amount of the reticle.

FIG. 2 is a diagram schematically showing a configuration of an aberration measuring device according to an embodiment of the present invention. Also in FIG. 2, the Z axis is parallel to the reference optical axis of the projection optical system 15 (PL), and the Y axis is parallel to the plane of FIG. 2 in a plane perpendicular to the reference optical axis. The X axis is set perpendicular to the paper in the figure. In the aberration measuring apparatus of the present embodiment, the projection optical system 15 (corresponding to the projection optical system PL in FIG. 1) to be measured is irradiated with a light beam having an exposure wavelength from the object side (the reticle R side). The light beam is received on the image side (Wafer W side). Then, based on the light beam received on the image side, the aberration (wavefront aberration) generated when transmitting through the projection optical system 15 is measured.

Referring to FIG. 2, the aberration measuring apparatus according to the present embodiment has the same configuration as the exposure apparatus of FIG. In addition, a light source 1 including one F ₂ laser light source (wavelength: 157 nm) or one ArF excimer laser light source (wavelength: 193 nm) is provided. The light beam L 1 emitted from the light source 1 enters the shaping optical system 7 via the mirror 3 and the beam window 4. As described above, since such a short-wavelength light beam is strongly absorbed by oxygen in the atmosphere, the light path from the light source 1 to the beam window 4 is covered with the airtight shielding member 5. Similarly, the optical path from the shaping optical system 7 to a test reticle 14 described later is also covered with an airtight shielding member 6. The insides of the shielding members 5 and 6 are filled (gas replacement) with a gas such as nitrogen or a rare gas, which has a small absorption for the used wavelength. Alternatively, the insides of the shielding members 5 and 6 may be evacuated.

The shaping optical system 7 is an optical system for converting the light beam 1 into a substantially parallel light beam and making the illuminance in the light beam substantially uniform, and includes a beam expander, a cylindrical lens, and the like. The light beam L 2, which is converted into a parallel light beam by the operation of the shaping optical system 7 and has uniform illuminance, enters the polarization control optical system 8. The polarization control optical system 8 is a characteristic component of the present invention, and controls the polarization state of the incident light beam L2 to a desired state. The detailed configuration and operation of the polarization control optical system 8 will be described later. The light beam L 3 whose polarization state is controlled by the operation of the polarization control optical system 8 is reflected by the mirror 9 and then enters the movable light transmission optical system 10.

The movable light-sending optical system 10 includes a mirror 11 and a condenser lens group 12. Accordingly, the light beam L3 reflected by the mirror 9 and incident on the movable light transmitting optical system 10 is reflected by the mirror 11 and condensed through the condenser lens group 12, and then the light beam L3. Illuminate the pattern for inspection on Stretchle 14. Here, the movable light-transmitting optical system 10 that integrally holds the mirror 11 and the condenser lens group 12 moves on the guide rail 13 provided on the shielding member 6 on the test reticle 14. It is configured to be two-dimensionally movable along a plane (XY plane) parallel to the plane. Thus, the light beam L3 via the movable light-transmitting optical system 10 can illuminate an arbitrary position on the test reticle 14.

The light beam (measurement light beam) transmitted through the inspection pattern on the test reticle 14 enters the projection optical system 15 to be measured. The light beam incident on the projection optical system 15 is After passing through the lenses 15 1 and 15 2 and being reflected by the first reflecting surface of the plane mirror 15 3, the light enters the concave reflecting mirror 15 6 via the lenses 15 4 and 15 5. The light beam reflected by the concave reflecting mirror 156 enters the plane mirror 153 again through the lenses 154 and 155. The light beam reflected by the second reflecting surface of the flat mirror 15 3 passes through the lenses 15 7, 15 8, 15 9, 16 0, 16 1, 16 2, 16 3 and 16 4. The light sequentially passes through and enters the aberration measurement unit 17.

Here, the aberration measurement unit 17 is arranged with reference to a position (image plane position) where the wafer is arranged when the projection optical system 15 is used in the exposure apparatus. When the projection optical system 15 is designed on the assumption that an F ₂ laser light source is used, almost all lenses constituting the optical system are made of a cubic system such as fluorite (calcium fluoride crystal). It is formed of a crystalline material. Further, even when the projection optical system 15 is designed on the assumption that an ArF excimer laser light source is used, a lens formed of a cubic crystal material such as fluorite is included. In the present embodiment, a catadioptric projection optical system ₍ 15 is assumed, but the optical system to be measured may be a refraction type. The aberration measurement unit 17 is a projection optical system 1 This unit measures the aberration (wavefront aberration) of 5, and its detailed configuration and operation will be described later.The aberration measurement unit 17 is a stage that can move along the XY plane on the surface plate 24. In this embodiment, the aberration measuring unit 17 and the movable light-transmitting optical system 10 are set in a positional relationship optically corresponding to each other via the projection optical system 15. This makes it possible to measure the wavefront aberration of the projection optical system 15. Then, while maintaining this optical correspondence, the aberration measurement unit 17 and the movable light transmission optical system 10 are placed on the XY plane. By moving the projection optical system 15 two-dimensionally along the It is possible to go-between aberration measurement.

Here, for the internal optical path of the aberration measurement unit 17 and the optical path between the projection optical system 15 and the aberration measurement unit 17, in order to avoid absorption of light by oxygen, the space is replaced with a gas, Or it is necessary to make a vacuum. Therefore, the aberration measurement unit 17, the stage 19, the surface plate 24, and the movable mirror 18, which will be described later, are covered with the purge partition 16, and the inside thereof is gas-purged or evacuated. Also purge Between the bulkhead 16 and the surface plate 24, vibration isolator 26A and 26B are provided. In order to further improve the accuracy of the aberration measurement, it is preferable to measure the position of the aberration measurement unit 17 and the position of the movable light transmitting optical system 10 by measuring means such as an interferometer. In the example shown in FIG. 2, a laser-interferometer 22 for measuring the position of the aberration measurement unit 17 is installed on the pedestal 21. The laser light emitted from the laser interferometer 22 enters the inside of the purge bulkhead 16 through the airtight glass window 16 a provided in the purge bulkhead 16, and is provided on the stage 19. After being reflected by the moving mirror 18, it returns to the laser-interferometer 22 through the glass window 16 a. The laser interferometer 22 measures the position of the reflecting surface of the movable mirror 18 and thus the position of the aberration measurement unit 17.

FIG. 2 shows only the interferometer 22 for measuring the position in the Y direction of the aberration measurement unit 17, but it is more preferable to provide an interferometer for measuring the position in the X direction. Needless to say. Similarly, it is preferable to provide a pair of interferometers for measuring the positions of the movable light transmitting optical system 10 in the X and Y directions. The aberration information measured by the aberration measurement unit 17 is transmitted to the outside as an electric signal. In this case, in order to guide the signal line (electrical wiring) 28 from the aberration measurement unit 17 to the outside of the purge partition 16, a current introducer 27 for a vacuum device provided on the purge partition 16 is used. Is good.

Thus, the signal line 28 led to the outside via the current introducer 27 is connected to the processing device 29. The processing device 29 performs signal processing on the aberration information detected by the aberration measurement unit 17 to calculate the wavefront aberration of the projection optical system 15. Further, the processing device 29 reads the position of the aberration measurement unit 17 based on the output from the laser-interferometer 22 as necessary, and supplies a movement command to the stage 19. A signal line 25 from the processing device 29 to the stage 19 is guided to the inside of the purge partition 16 via a current introducer 26 provided in the purge partition 16.

FIG. 3 is a diagram schematically showing a configuration of a sharing interferometer as the aberration measurement unit of FIG. In the present embodiment, a sharing interferometer 17A as shown in FIG. 3 can be used as the aberration measurement unit 17 in FIG. in this case, A so-called pinhole (a minute transmission opening formed on the back ground of the light-shielding portion) is used as an inspection panel for the test reticle 14. Referring to FIG. 3, a projection image of a pinhole as an inspection pattern of the test reticle 14 by the projection optical system 15 is formed at a position FP near and above the sharing interferometer 17A. The divergent luminous flux from the pinhole image formed at position FP is converted to a parallel luminous flux by the lens group 171, and is a phase grating with the same pitch (duty is 1: 1 and phase difference is 180 degrees) The two parallel plane plates 17 2 and 1 73 on which 17 2 a and 17 3 a are formed are incident. The light beam incident on the first parallel plane plate 172 is split by the first phase grating 1772a into two diffracted lights separated by a predetermined angle left and right in the figure. Next, the two light beams enter the second parallel plane plate 173, and are diffracted again by the second phase grating 173a in the left and right directions at the same angle.

As a result, the light beam (light beam A) diffracted to the left at the first phase grating 1772a and to the right at the second phase grating 1773a, and the first phase grating A light beam diffracted to the right at 172a and then diffracted to the left at the second phase grating 173a (a light beam is transmitted to the lens group 174 along the same direction as shown by the solid line in the figure. The luminous flux condensed through the lens group 174 is condensed through the lens group 176, and then the two luminous fluxes are focused on the imaging surface of the image sensor 174 such as a CCD. The light beam A and the light beam B are originally the same light beam and have the wavefront difference information of the projection optical system 15. However, on the image sensor 1777, the phase grating 17a is formed. Is determined by the pitch along the optical axis between the pitch of the phase grating 1 and the pitch of the phase grating. Therefore, the light beam A and the light beam B are superposed with a positional shift.

In this way, the interference fringes on the image sensor 1777 show a difference corresponding to the above-mentioned position shift amount of the wavefront aberration information of the projection optical system 15, and the projection optical system is analyzed by analyzing the interference fringes. The wavefront aberration (aberration) of 15 can be calculated. As described above, by changing the distance between the phase gratings 17 2 a and 17 3 a, the amount of this position shift, that is, the difference distance can be changed. It is desirable that 72 and 173 have a structure that can be moved in the optical axis direction (vertical direction in the figure).

In addition, the diffracted light generated from the phase gratings 172a and 1773a generates not only the light flux A and the light flux B described above, but also unnecessary diffracted light as indicated by the broken line in the figure, and the unnecessary light has a wavefront aberration. The accuracy of the measurement may be degraded. Therefore, it is preferable to provide an aperture stop 175 between the lens group 174 and the lens group 176, and shield unnecessary diffracted light with the aperture stop 175. Even in the sharing interferometer 17A, it is necessary to replace the inside of the gas with the inside or to evacuate the inside so that the measuring light to be used is not absorbed. In some cases, it is desirable that the signal line from the image sensor 177 be guided to the outside of the sharing interferometer 17A via a current introducer for a vacuum device or the like.

FIG. 4 is a diagram schematically showing a configuration of a Schattt-Hartmann sensor as the aberration measurement unit of FIG. In the present embodiment, as the aberration measurement unit 17 in FIG. 2, a Schartsquart sensor 17B as shown in FIG. 4 may be used. Also in this case, a pinhole is used as an inspection pattern on the test reticle 14. A projection image of the pinhole by the projection optical system 15 is formed at a position FP near and above the Schattsquart Man sensor 17B.

The divergent light beam from the pinhole image formed at the position FP is converted into a parallel light beam via the lens group 178, and then enters the microlens array 179. The micro lens array 179 is an optical element configured by two-dimensionally densely arranging a large number of micro lens elements like a fly-eye lens. When a parallel light beam enters the micro-lens array 179, the incident light beam is split into wavefronts by the respective minute lens elements, and thereafter, condensing points 181 are formed in the vicinity of the side focal plane. An imaging surface of an imaging element 180 such as a CCD is positioned at a position where a large number of light condensing points 181 are formed. In this way, the position of each focal point 18 1 is measured by the image sensor 180.

The luminous flux incident on the Schatts-Hartmann sensor 17B is a luminous flux transmitted through the projection optical system 15, and the wavefront thereof is changed by the aberration (wavefront aberration) of the projection optical system 15. It is slightly deformed. As a result, the position of each condensing point 18 1 is shifted by a small amount depending on the wavefront aberration of the projection optical system 15 from each reference position where light is condensed when the projection optical system 15 has no aberration. Shift. Therefore, the Schatt-Khaltmann sensor 17 B can calculate the wavefront aberration of the projection optical system 15 by measuring the amount of displacement of each light-collecting point 18 1 from each reference position.

The aberration measurement unit 17 is not limited to the above-described sharing interferometer 17A and Shack-Hartmann sensor 17B, but may use, for example, the aforementioned PDI. Alternatively, a method of detecting the projection image itself of the pinhole as the inspection pattern on the test reticle 14 by the projection optical system 15 and calculating the wavefront aberration from the Fourier transform of the aerial image can be used.

In the above description, the projection optical system 15 to be measured is irradiated with a light beam having an exposure wavelength from the object side (reticle side), and the projection is performed based on the light beam received on the image side (wafer side). A configuration is used to measure the aberration (wavefront aberration) generated when the light passes through the optical system 15. However, on the contrary, when the projection optical system 15 is irradiated with a light beam having an exposure wavelength from the image side (wafer side) from the image side (wafer side) and passes through the projection optical system 15 based on the light beam received on the object side. It is also possible to adopt a configuration for measuring the wavefront aberration that has occurred.

In addition, as another method for measuring the wavefront aberration of the projection optical system 15, if a measurement method using a Fizeau interferometer ゃ Twyman Green interferometer is adopted, the image side of the projection optical system 15 or an object may be used. Either side can be set as the irradiation side (transmitting side) and the receiving side. In this case, a spherical reflector whose center is the spherical point is set near the focal point of the measurement light beam on the other side that is neither the irradiation side nor the light receiving side. What is necessary is just to comprise so that measurement light may be returned to a light receiving side. FIG. 5 is a diagram schematically showing a configuration of the polarization control optical system of FIG. Referring to FIG. 5, the incident light beam L2 to the polarization control optical system 8 is incident on a location prism 81 composed of a first prism member 81A and a second prism member 81B. . The location prism 81 is formed of a uniaxial crystal material having a large birefringence such as magnesium fluoride. The composition of the Rossion prism 81 is a general Rossion It is the same as the prism, and the optical axis of the uniaxial crystal is set in the direction parallel to the traveling direction of the light beam L2 (Z direction) in the first prism member 81A. The optical axis of the axial crystal is set in the direction (Y direction) perpendicular to the plane of the paper in Fig. 5.

In the location prism 81, of the incident light beam L2, a linearly polarized light beam having a polarization direction in a direction parallel to the paper surface (X direction) goes straight and changes the polarization direction in a direction perpendicular to the paper surface (Y direction). The linearly polarized light beam has a refraction effect. That is, the light beam L 2 incident on the location prism 81 is composed of linearly polarized light LO (shown by a solid line) having a polarization direction parallel to the paper surface and linearly refracted light LE having a polarization direction perpendicular to the paper surface. (Shown by a broken line in the figure). The refracted light LE is shielded by the aperture stop 84, and only the straight light LO passes through the aperture stop 84 and enters the 1Z2 wavelength plate 82. Thus, the location prism 81 constitutes a linearly polarized light separating means for separating a predetermined linearly polarized light beam polarized along a predetermined direction from an incident light beam. In addition, since one F ₂ laser beam and one Ar F laser beam have a certain degree of polarization characteristics, if the polarization direction of the straight-ahead light LO matches the direction of the linearly polarized light component contained more in the incident light beam L 2, the amount of light will be secured. It is advantageous in terms of. For this purpose, it is preferable that the optical axis of the second prism member 81B and the direction of the linearly polarized light component included in the light beam L2 be orthogonal to each other.

As described above, the straight light LO enters the half-wave plate 82. The half-wave plate 82 is formed of a uniaxial crystal material such as magnesium fluoride or a cubic crystal material such as fluorite. When the half-wave plate 82 is formed of a uniaxial crystal, its optic axis is set to be orthogonal to the Z axis. This is the same as a general 1Z2 wavelength plate, and the setting method of the length S1 of the 1/2 wavelength plate 82 is the same as that of a general 1Z2 wavelength plate.

On the other hand, when the 1Z two-wavelength plate 82 is formed of a cubic crystal material such as fluorite, the crystal axis [1 10] is set so as to coincide with the Z axis. This is because the birefringence is maximized when the light beam travels along a direction parallel to the crystal axis [1 10]. If the crystal is fluorite, the birefringence for light traveling in a direction parallel to the crystal axis [110] is The difference between the refractive index n 100 of light having a polarization direction (electric field direction) in the direction of [100] and the refractive index n 01 1 of light having a polarization direction in the direction of the crystal axis [0—11] is for a r F laser length 1 93 nm 3. is about 2 X 10- ^7, the wavelength 1 of 57 nm? ₂ is about 1 1. 2 X 10- ⁷ for record one The first light.

This is for each traveling 1 cm fluorite, relative positional relationship between the wavefronts of both linearly polarized light progresses, the Ar F laser beam 3. 2 nm varies, the _2, single The first light 1 1.2 It indicates that the value changes by nm. Therefore, if the length S 1 of the 1Z 2 wave plate 82 made of fluorite is set to 7.0 cm, the F ₂ laser light will be 7.0 I I. 2 nm 78 nm An optical path difference of 1 Z 2 wavelength occurs between the polarized lights. That is, it acts as a 12-wave plate.

The 12-wavelength plate 82 is installed so as to be rotatable around the Z direction as a rotation axis. Therefore, depending on the rotation position of the 1Z2 wave plate 82, the polarization state of the exit light beam L3 is changed to the linear polarization state having the polarization direction in the X direction parallel to the paper surface similarly to the incident light beam L0, and to the Y direction perpendicular to the paper surface. It is possible to switch between a linear polarization state having a polarization direction. Thus, the 12-wavelength plate 82 constitutes a polarization plane rotating means for rotating the polarization plane of a predetermined linearly polarized light flux about the central axis of the light flux. In the present embodiment, a linearly polarized light beam having a polarization direction in the X direction is made incident on the projection optical system 15, and the aberration of the optical system with respect to the X direction polarization is measured based on the light beam transmitted through the projection optical system 15. Next, a linearly polarized light beam having a polarization direction in the Y direction is made incident on the projection optical system 15, and the aberration of the optical system with respect to the Y direction polarization is measured based on the light beam transmitted through the projection optical system 15. Thus, based on the aberration measurement results obtained for the X-direction polarization and the aberration measurement results obtained for the Y-direction polarization, it is caused by the birefringence of the crystal lens formed of crystals such as fluorite. The residual aberration of the projection optical system 15 to be measured is measured.

Since the aberration measurement units (17A and 17B) illustrated in FIGS. 3 and 4 are both systems capable of measuring aberrations with linear polarization, two linear polarizations having polarization directions orthogonal to each other are used. There is no problem in measuring the aberration for each light beam. However, depending on the configuration of mirrors 9 and 11 shown in FIG. Since the optical state is changed, it is preferable that the mirrors 9 and 11 be configured so as not to change the polarization state of the light beam L3. In addition, the polarization direction of the transmitted light (straight light) LO of the location prism 81 is set to be P-polarized light or S-polarized light with respect to the reflection surfaces of the mirrors 9 and 11 (set not to be in an intermediate state). By doing so, it is also possible to prevent a change in the polarization state due to the mirrors 9 and 11.

FIG. 6 is a diagram showing a modification in which a pair of quarter-wave plates are used instead of the half-wave plate of FIG. The modification of FIG. 6 shows that the same effect can be obtained by using a pair of 1/4 wavelength plates 82A and 82B instead of the 1Z2 wavelength plate 82 of FIG. Referring to FIG. 6, the optical members 82A and 82B are both 1Z4 wave plates, and are formed of a uniaxial crystal material or a cubic crystal material. Similarly to the half-wave plate 92 in FIG. 5, both 1Z4 wave plates 82A and 82B are configured to be rotatable about the Z-axis direction.

When the 1Z4 wave plate 82B or 82A is formed of a uniaxial crystal material, the structure is the same as a general quarter wave plate. When the 1/4 wavelength plate 82B or 82A is made of a cubic crystal material, its structure is basically the same as that of the 1/2 wavelength plate 82 in Fig. 5, but its length S 2 and S 3 are halved. That is, for two lasers and one light, it becomes a quarter-wave plate with a length of 3.5 cm. The quarter-wave plate 82B on the incident side can convert the linearly polarized incident light LO into a circularly polarized light flux LT and emit it according to the set angle.

In this case, the light beam L3 emitted from the 1/4 wavelength plate 82A is a linearly polarized light beam having a polarization direction coinciding with the rotation direction of the 1/4 wavelength plate 82A. In other words, the light beam L3 can be converted into a linearly polarized light beam having an arbitrary polarization direction according to the rotation of the 1Z 4 wavelength plate 82A. Further, depending on the set angle of the 14-wavelength plate 82B, the emitted light beam LT can be made the same linearly polarized light as the incident light beam L O. In this case, depending on the rotation direction of the 1Z4 wavelength plate 82A, the emitted light beam L3 can be turned around or counterclockwise as a circularly polarized light beam.

When the 1Z2 wavelength plate 82 in FIG. 5 is used, the false light state of the emitted light L3 can be switched to two linear polarization states orthogonal to each other, but the two polarization states are changed. It cannot be rotated as a whole. On the other hand, when a pair of quarter-wave plates 8 2 B or 82 A in FIG. 6 is used, in addition to switching the polarization state of the emitted light L 3 to two linear polarization states orthogonal to each other, This is even more convenient because the two polarization states can be rotated as a whole. In addition, the emitted light L3 can be in a circularly polarized state. In this case, since the aberration of the projection optical system 15 can be measured with a light beam in a state close to natural light (randomly polarized light), the influence of birefringence can be reduced. It is also possible to perform ignored aberration measurement.

By the way, if the wavefront aberration due to the birefringence remaining in the projection optical system 15 is large, the difference between the wavefronts of predetermined orthogonal linearly polarized light in the light flux transmitted through the projection optical system 15 becomes large, and this is 1/2. Acting in the same way as a wave plate or a 1Z4 wave plate, the polarization state of a light beam may be changed. The polarization conversion measurement unit 30 shown in FIG. 7 is a device for measuring how much such polarization conversion occurs by the projection optical system 15. The polarization conversion measurement unit 30 is installed on the stage 19, for example, along with the aberration measurement unit 17 in FIG.

Referring to FIG. 7, light transmitted through the pinhole pattern on the test reticle 14 forms a pinhole image at a position FP near and above the polarization conversion measurement unit 30 via the projection optical system 15. The divergent luminous flux from the pinhole image formed at position FP is converted into a parallel luminous flux by the lens group 182, and then passed through a pair of 1/4 wavelength plates 183 and 1884 to the location prism. It is incident on 1 85. In the position prism 185, the light beam is split by the linearly polarized light component, and the linearly polarized light beam L10 having a polarization direction parallel to the plane of FIG. 7 is input to an image sensor 186 such as a CCD. Shoot.

Similar to the pair of quarter-wave plates 82B and 82A shown in FIG. 6, depending on the rotation angle of the pair of quarter-wave plates 1833 and 1884 with respect to the optical axis, the projection optical system 1 The polarization direction of the luminous flux emitted from 5 can be optimized with respect to the Rossion prism 185. In other words, a pair of quarter-wave plates 18 3 and 18 are arranged so that the polarization direction of the incident light on the position prism 185 and the polarization direction of the emitted light (straight light) L 1〇 are the same. Initialize the rotation direction of 4. And in this initial setting state, The light intensity signal SGI from the image sensor 186 is collected. This is basically nothing but measuring the transmittance of the projection optical system 15 in the pupil plane.

Next, a pair of quarter-wave plates 18 3 and 18 4 are set so that the polarization direction of the incident light on the prism 1885 and the polarization direction of the emitted light (straight light) L 10 are orthogonal to each other. Set the rotation direction of. Then, even in this setting state, the light amount signal SG2 from the image sensor 186 is sampled. In this case, if the projection optical system 15 has no wavefront deviation (retardation) between orthogonal linearly polarized lights due to birefringence, the light quantity signal SG2 should be zero. Therefore, the conversion ratio of polarized light in the projection optical system 15 can be calculated from the ratio between the light amount signal SG2 and the light amount signal SG1. Also, based on this, the amount of wavefront aberration associated with the birefringence of the projection optical system 15 can be roughly calculated.

By the way, when the measurement result of the residual aberration associated with the birefringence in the projection optical system 15 is obtained using the aberration measurement apparatus of the present embodiment, the measurement result, the design data of the projection optical system 15 and the crystal Based on the birefringence characteristics of the material and the like, it is possible to determine which lens element should be adjusted and how to remove the residual aberration caused by birefringence. The specific adjustment method differs depending on the type of the projection optical system 15 and cannot be unconditionally determined. In general, clocking adjustment to rotate a lens (15 1 to 16 4) made of a crystal such as fluorite around the optical axis, movement adjustment to move along the optical axis, and almost orthogonal to the optical axis A shift adjustment that moves along the surface to be moved, a tilt adjustment that inclines with respect to the optical axis, and the like can be applied.

That is, in the adjustment method according to the present embodiment, in the procedure for removing the wavefront aberration caused by the influence of birefringence from the projection optical system 15, the residual aberration associated with the birefringence is measured by the aberration measuring device of the present embodiment. Then, based on the measured aberration results, the design data of the projection optical system 15 and the birefringence characteristics of the crystalline material such as fluorite, etc., which lens element is used to correct the residual aberration caused by birefringence? Calculate whether adjustment is necessary. Then, optical adjustment of the projection optical system 15 is performed based on the calculation result. After the optical adjustment of the projection optical system 15, the residual difference due to birefringence is measured again by using the aberration measuring device of the present embodiment. Refer to the measured aberration results and confirm that the aberrations associated with birefringence If the correction has been made, the adjustment process is completed, but if the aberrations associated with birefringence have not been sufficiently corrected, the above adjustment process will be repeated.

In the above-described embodiment, a calcium fluoride crystal (fluorite) is used as the birefringent optical material. However, the present invention is not limited to this, and other uniaxial crystals, for example, a barium fluoride crystal (fluorite) may be used. B a F ₂ ), lithium fluoride crystal (L i F), sodium fluoride crystal (N a F), strontium fluoride crystal (S r F ₂ ), beryllium fluoride crystal (B e F ₂ ), etc. Other crystalline materials that are transparent to ultraviolet light can also be used. Among these, barium fluoride crystals have already been developed for large crystal materials with diameters exceeding 200 mm, and are promising as lens materials. In this case, it is preferable that the crystal axis direction such as vacuum fluoride (B a F ₂ ) is also determined in accordance with the present invention. In the exposure apparatus of the above-described embodiment, the reticle (mask) is illuminated by the illumination device. Process), exposing the transfer pattern formed on the mask to the light-sensitive substrate using the projection optical system (exposure process), resulting in a micro device (semiconductor device, imaging device, liquid crystal display device, thin film magnetic head, etc.) ) Can be manufactured. The flowchart of FIG. 8 shows an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the present embodiment. It will be described with reference to FIG.

First, in step 301 of FIG. 8, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot of wafers. Then, in step 303, using the exposure apparatus of the present embodiment, the pattern image on the mask is sequentially exposed and transferred to each shot area on the one-port wafer via the projection optical system. Is done. Thereafter, in step 304, the photoresist on the one lot of wafers is developed, and then in step 305, etching is performed on the one lot of wafers using the resist pattern as a mask. Thereby, a circuit pattern corresponding to the pattern on the mask is formed in each shot area on each wafer.

Thereafter, a device such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer and the like. According to the semiconductor device manufacturing method described above, A semiconductor device having a fine circuit pattern can be obtained with good throughput. In steps 301 to 305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and the respective steps of exposure, development, and etching are performed. Prior to forming a silicon oxide film on the wafer in advance, it is needless to say that a resist may be applied on the silicon oxide film, and each step of exposure, development, etching and the like may be performed.

In the exposure apparatus of the present embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart in FIG. In FIG. 9, in a pattern forming step 401, a so-called photolithography step is performed in which a mask pattern is transferred and exposed to a photosensitive substrate (eg, a glass substrate coated with a resist) using the exposure apparatus of the present embodiment. Is executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes various processes such as a developing process, an etching process, a resist stripping process, and the like, whereby a predetermined pattern is formed on the substrate, and the process proceeds to a next color filter forming process 402. . Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or R, G, A color filter is formed by arranging a plurality of sets of three stripe filters B in the horizontal scanning line direction. Then, after the color filter forming step 402, a cell assembling step 403 is executed. In the cell assembling step 403, a liquid crystal panel is formed using the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402. (Liquid crystal cell). In the cell assembling step 403, for example, between the substrate having a predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402. Injects liquid crystal to manufacture liquid crystal panels (liquid crystal cells).

Then, in the module assembly process 404, the assembled liquid crystal panel (liquid A liquid crystal display element is completed by attaching various components such as an electric circuit and a backlight that perform the display operation of the crystal cell. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

In the above-described embodiment, the present invention is applied to the projection optical system mounted on the exposure apparatus. However, the present invention is not limited to this, and the present invention may be applied to other general optical systems. It can also be applied. Further, in the embodiment described above, but using a 1 9 3 nm F ₂ laser primary light source for supplying wavelength light A r F excimer laser primary light source and 1 5 7 nm supplying wavelength light, limited to Instead, for example, an Ar ₂ laser light source that supplies light having a wavelength of 126 nm can be used. Industrial applicability

As described above, in the aberration measurement device and the aberration measurement method of the present invention, the aberration measurement device and the aberration measurement method determine the difference between the aberration measurement values of two linearly polarized light beams having polarization directions orthogonal to each other, thereby forming a crystal such as fluorite. The residual error of the optical system caused by the birefringence of the optical member can be measured with high accuracy. In addition, based on the aberration result measured with high accuracy using the aberration measuring device and the aberration measuring method of the present invention, residual aberration of the optical system due to birefringence can be satisfactorily removed. Further, according to the present invention, it is possible to realize an exposure apparatus including an optical system having good optical performance and good optical adjustment. Further, according to the present invention, a high-performance microdevice can be manufactured according to a high-resolution exposure technique using an exposure apparatus equipped with an optical system having good optical performance.

Claims

The scope of the claims

1. An aberration measuring apparatus for measuring aberration of an optical system including an optical member formed of a crystal belonging to a cubic system,

A light beam irradiation unit for irradiating the optical system with a predetermined light beam,

The light beam irradiation unit includes a first linearly polarized light polarized along a first direction and a second linearly polarized light polarized along a second direction different from the first direction, An aberration measuring device comprising: a polarization switching unit for switching a polarization state of the predetermined light flux.

2. In the aberration measuring device according to claim 1,

Aberration measurement, wherein the first direction and the second direction are substantially orthogonal to each other.

3. In the aberration measuring device according to claim 1 or 2,

The aberration measurement unit comprises: a first aberration measurement result measured based on a light beam transmitted through the optical system irradiated with the first linearly polarized light beam; and the second linearly polarized light beam irradiated by the second linearly polarized light beam. An aberration measuring device, wherein an aberration of the optical system caused by a birefringence of the optical member is measured based on a second aberration measurement result measured based on a light beam transmitted through the optical system.

4. In the aberration measuring apparatus according to any one of claims 1 to 3,

The polarization switching means,

Linear polarization separation means for separating a predetermined linearly polarized light beam polarized along a predetermined direction from the incident light beam; A polarizing plane rotating means for rotating the polarization plane of the predetermined linearly polarized light beam separated via the linearly polarized light separating means around a central axis of the predetermined linearly polarized light beam. Aberration measuring device.

5. The aberration measuring apparatus according to claim 4, wherein

Wherein said linearly polarized light separating means has a location prism.

6. In the aberration measuring device according to claim 4 or 5,

The aberration measuring apparatus, wherein the polarization plane rotating means has a half-wave plate rotatable about the central axis.

7. The aberration measuring apparatus according to claim 4 or 5, wherein

The polarization plane rotating means includes a first 1Z4 wavelength plate rotatable about the central axis, and a second 1/4 wavelength plate rotatable about the central axis. Characteristic aberration measurement device.

8. In the aberration measuring apparatus according to any one of claims 1 to 7,

Aberration characterized in that the wavelength of the light beam is 1 93 nm or 1 57 nm

9. An aberration measuring method for measuring aberration of an optical system including an optical member formed of a crystal belonging to a cubic system,

A first aberration measurement step for measuring aberration of the optical system based on a light beam transmitted through the optical system irradiated with the light beam of the first linearly polarized light, A second irradiation step of irradiating the optical system with a second linearly polarized light beam polarized along a second direction different from the first direction;

10. The method for measuring aberration according to claim 9, wherein:

An aberration measurement method, wherein the first direction and the second direction are substantially orthogonal to each other.

11. The aberration measuring method according to claim 9 or 10, wherein the wavelength of the light beam is 193 nm or 157 nm.

12. An aberration measurement result of the optical system measured by using the aberration measurement device according to any one of claims 2 to 8, or claim 9 to 11 The method according to any one of claims 1 to 6, wherein the aberration remaining in the optical system due to the birefringence of the optical member is substantially reduced based on an aberration measurement result of the optical system measured using the aberration measurement method. An adjustment method comprising an optical adjustment step of optically adjusting the optical system to remove the optical system.

1 3. In the adjustment method described in claim 12,

The optical adjustment step includes: a clocking step of rotating the optical member around an optical axis of the optical system; a moving step of moving the optical member along the optical axis; At least one of a shift step of moving the optical member along a plane substantially perpendicular to the tilt direction and a tilt step of tilting the optical member with respect to the optical axis. An adjustment method comprising the steps of:

1 4. An illumination optical system for illuminating the mask,

An optical system adjusted by the adjustment method according to claim 12 or 13 for forming an image of a pattern formed on the mask on a photosensitive substrate. Exposure apparatus.

15. An exposure step of exposing the pattern of the mask to the photosensitive substrate using the exposure apparatus according to claim 14,

A developing step of developing the photosensitive substrate exposed in the exposing step.