JP2000311848A - Method for projection exposure and projection aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain lowering of fidelity of a transferred pattern, lowering of contrast of a projection image, etc., when a projection optical system which is constituted with a part of imaging luminous flux being actually screened is used. SOLUTION: A reticle 13 is illuminated by illuminating light IL for exposure from an illuminating optical system and the illuminating light IL, which passed through the reticle 13 arrives at a wafer 19 via a projection optical system 18 consisting of lenses L11 to L24, a main mirror M1 having an opening part 61 whose center is an optical axis, a lens element L2 and a sub-mirror M2 having an opening part 62, whose center is an optical axis and an image of a reticle pattern, is transferred on the wafer 19. Distribution of an secondary light source at a pupil surface in an illuminating optical system is optimized so as to be weak at the central part and strong in the outer circumferential part corresponding to that imaging luminous flux is practically screened at a central part, etc., of the opening part 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a device such as a semiconductor device, an image pickup device (CCD or the like), a liquid crystal display device, or a thin film magnetic head by using a photolithography technique to form mask patterns on a substrate. The present invention relates to a projection exposure method and an apparatus used in a step of exposing and transferring to a substrate.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device or the like, a fine original pattern (reticle pattern) formed on a reticle as a mask is projected via a projection optical system onto a wafer (or a wafer) on which a photoresist as a substrate is formed. A projection exposure apparatus such as a batch exposure type or a scanning exposure type for transfer onto a glass plate or the like is used. In such a projection exposure apparatus, assuming that the wavelength of the exposure light is λ and the numerical aperture of the projection optical system is NA, the resolution is proportional to λ / NA. Increasing the NA of the projection optical system has been performed.

As a result, at present, the exposure light having a wavelength of 24
An 8 nm KrF excimer laser beam has been used, and an exposure apparatus using an 193 nm wavelength ArF excimer laser as an exposure light source is under development. And
An exposure apparatus using a shorter wavelength 157 nm F ₂ laser as an exposure light source has also been proposed. The numerical aperture of the projection optical system is about 0.7.

[0004]

As described above, developments have been made to increase the resolution than before, but in order to cope with higher integration of semiconductor integrated circuits and the like, the exposure wavelength must be further increased. It is necessary to shorten the wavelength and increase the NA of the projection optical system. However, in the case of using light in the wavelength range of about ArF excimer laser light (wavelength 193 nm) or less, that is, vacuum ultraviolet light, as the exposure light, the glass material of the refractive member that transmits the exposure light at a high transmittance is synthetic quartz or It is limited to fluorite. Further, when the exposure wavelength becomes about 160 nm or less, usable glass materials include fluorite. If the types of glass materials that can be used are limited in this way, it becomes difficult to properly correct various aberrations in a projection optical system including only a refraction member.

Further, if an attempt is made to increase the NA of a projection optical system constituted by using only a refracting member, the amount of expensive fluorite or the like used increases, and the manufacturing cost of the projection exposure apparatus may increase significantly. is there. In order to solve such a problem, for example, in Japanese Patent Application No. 10-370143, a projection optical system combining a refraction member and a reflection member having a transmission part (opening) formed in a part of a reflection surface is disclosed in the present application. Suggested by people. According to this projection optical system, chromatic aberration can be efficiently corrected particularly by using the reflection member, and the amount of expensive glass material for the refraction member can be reduced.

However, when such a projection optical system is used, the light flux passing through the center of the transmitting portion of the reflecting member is actually a part of the image forming light flux that should reach the wafer from the reticle via the reflecting member. It will be shielded from above.
In this way, since the light flux actually blocked is small, it is considered that there is almost no adverse effect in the current application. However, as circuit patterns to be transferred become finer and more highly integrated in the future, such a partial shielding of the image forming light beam reduces the fidelity of the extremely fine pattern transferred onto the wafer. Or the contrast of a specific extremely fine pattern image may be reduced.

SUMMARY OF THE INVENTION In view of the foregoing, the present invention reduces the fidelity of a transferred pattern or reduces a projected image when using a projection optical system having a configuration in which a part of an image forming light beam is virtually blocked. It is an object of the present invention to provide a projection exposure method and a projection exposure apparatus which can suppress the deterioration of the imaging characteristics such as the decrease in contrast of the image. Still another object of the present invention is to provide a device manufacturing method capable of manufacturing a high-performance device using such a projection exposure method.

[0008]

According to the projection exposure method of the present invention, a mask (13) is illuminated with an exposure beam from an illumination optical system, and the pattern of the mask is projected onto a substrate (19) via the projection optical system. In a projection exposure method for transferring, the projection optical system has a transmission portion (61, 62) through which the exposure beam passes, in a region including the optical axis of the projection optical system or in a region near the optical axis. And an optical Fourier transform surface of the illumination optical system with respect to the pattern surface of the mask, that is, the illuminance distribution of the exposure beam on the pupil surface. Weak in the area including the optical axis of the illumination optical system or in the area near this optical axis,
This is set strongly at the outer peripheral portion away from the optical axis.

According to the present invention, the reflection members (M1, M2) are used inside the projection optical system, for example, the region near the optical axis of the projection optical system serving as a transmission part. Therefore, if the exposure beam from the illumination optical system is a normal exposure beam, the optical path passing through the central portion of the transmission section in the imaging optical path from the mask to the substrate is effectively blocked. Will be lost. That is, of the light beams that should be reflected by the reflecting member, the light beam near the center of the reflecting member near the optical axis is not reflected by the transmitting portion and cannot reach the substrate. On the other hand, in the present invention, since the illuminance distribution of the exposure beam on the pupil plane in the illumination optical system is optimized, even if a reflection member having a part as a transmission part is used, It is possible to prevent a decrease in the fidelity of a pattern transferred thereon and a decrease in the contrast of an image of a specific pattern.

Next, a first projection exposure apparatus according to the present invention illuminates a mask (13) with an exposure beam from an illumination optical system, and the pattern of the mask is projected onto a substrate (19) via the projection optical system. A projection exposure apparatus for transferring, wherein the projection optical system has transmission portions (61, 62) through which the exposure beam is transmitted in a region including the optical axis of the projection optical system or in a region near the optical axis. And an optical Fourier transform surface of the illumination optical system with respect to the pattern surface of the mask, that is, the illuminance distribution of the exposure beam on the pupil surface. An illuminance adjusting member (43 to 46) is provided which is weak in a region including the optical axis of the illumination optical system or in a region near the optical axis, and is strongly set in an outer peripheral portion distant from the optical axis.

A second projection exposure apparatus according to the present invention illuminates a mask (13) with an exposure beam from an illumination optical system, and transfers the pattern of the mask onto a substrate (19) via the projection optical system. An optical Fourier transform plane of the projection optical system with respect to the pattern surface of the mask, that is, a pupil plane or an arbitrary point on the mask near the pupil plane. A part of the image forming optical path to the image position is substantially blocked, and the optical Fourier transform plane of the illumination optical system with respect to the pattern surface of the mask, that is, the illuminance distribution of the exposure beam at the pupil plane is obtained. An illuminance adjusting member (46) is provided which is set to be strong in eight or more regions arranged at substantially equal angular intervals around the optical axis of the illumination optical system.

With these projection exposure apparatuses, the projection exposure method of the present invention can be carried out. Further, when the illuminance adjustment member sets the illuminance distribution of the exposure beam to be strong in four or more regions, for example, transfer fidelity to a pattern that is periodic in two orthogonal directions can be improved,
When the illuminance distribution is set to be strong in eight or more regions, the transfer fidelity for a pattern that is periodic in an oblique direction with respect to the orthogonal pattern can be improved.

Next, the device manufacturing method according to the present invention includes a step of transferring a device pattern (mask pattern) onto a work piece (substrate) using the projection exposure method of the present invention. According to the present invention, high-fidelity, high-performance, highly integrated devices can be mass-produced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a step-and-scan type projection exposure apparatus using vacuum ultraviolet light as an exposure beam (illumination light for exposure). FIG. 1 is a schematic configuration diagram showing a projection exposure apparatus of the present embodiment. In FIG. 1, a fluorine laser (F ₂ laser: wavelength of 157 nm) is used as an exposure light source 1. However, as the exposure light source 1, another laser light source such as an ArF excimer laser, a harmonic generation device of a YAG laser, a harmonic conversion device of a semiconductor laser, or the like may be used. Exposure illumination light (exposure light) IL composed of pulse laser light having a wavelength of 157 nm emitted from the exposure light source 1 is:
The cross-sectional shape is shaped by the shaping optical system 2 and is incident as an exposure beam on an optical integrator (homogenizer) 3 for uniformizing the illuminance distribution.

The illumination light IL emitted from the optical integrator 3 passes through a first relay lens 5, a mirror 6 for bending the optical path, and a second relay lens 7, and reaches a field stop (reticle blind) 8, where the illumination field is elongated. Limited to a rectangular area. Illumination light IL that has passed through the field stop 8
Are the first condenser lens 9 and the second condenser lens 1
0, a pattern area on the pattern surface (lower surface) of the reticle 13 as a mask is illuminated via the optical path bending mirror 11 and the third condenser lens 12. Exposure light source 1,
The illumination optical system includes a shaping optical system 2, an optical integrator 3, relay lenses 5, 7, a mirror 6, a field stop 8, condenser lenses 9, 10, 12, and a mirror 11, and the optical axis of the illumination optical system. Is AX.

In this embodiment, a fly-eye lens is used as the optical integrator 3. At this time, a large number of secondary light sources are formed on the emission-side surface of the optical integrator 3, and the illumination light from these secondary light sources illuminates the reticle 13 in a superimposed manner, whereby the illuminance on the reticle 13 is increased. The distribution is made uniform.
In order to make the illuminance distribution uniform, the exit side surface of the optical integrator 3 (fly-eye lens) is optically Fourier-transformed with respect to the pattern surface of the reticle 13 by an optical system including the relay lens 5 and the condenser lens 12. They are arranged so as to match the plane that is in the conversion relationship, that is, the pupil plane IP of the illumination optical system.

On the pupil plane IP of the illumination optical system, an aperture switching member 4 for determining the numerical aperture of the illumination light is rotatably arranged. The main control system 24 for controlling the operation of the entire apparatus is controlled by the drive motor 47 to control the aperture switching member 4.
By controlling the rotation angle of the illumination light IL, a desired illumination system aperture stop (so-called “σ stop”) is set on the optical path of the illumination light IL.

FIG. 7 shows a plurality of illumination system aperture stops formed on a disc-shaped aperture switching member 4, and as shown in FIG. Aperture stop 41 with circular aperture, aperture stop 4 with small circular aperture for small coherence factor (σ value)
2. An aperture stop 43 for annular illumination having an annular aperture 43a having a relatively large inner diameter, an aperture stop 44 for annular illumination having an annular aperture 44a having a relatively small inner diameter, installed in the illumination optical system. Aperture stop 45 for deformed illumination having four apertures 45a arranged at equal angular intervals around the optical axis,
And an aperture stop 46 having eight apertures 46a arranged at equal angular intervals around the optical axis when installed in the illumination optical system.
Is arranged.

The deformed illumination is described in Japanese Patent Laid-Open No. 4-1 / 4-1.
No. 01148, JP-A-4-225357, JP-A-4-225514 and the like. By performing the deformed illumination to deform the shape of the secondary light source, it is also possible to improve the resolution of the projection optical system for a predetermined periodic pattern, for example. Also,
In the case of performing deformed illumination or annular illumination, simply blocking the illumination light in an unnecessary area with an illumination system aperture stop may decrease the illumination efficiency and decrease the throughput of the exposure process. Thus, in order to prevent a reduction in illumination efficiency, when performing modified illumination or annular illumination, for example, the optical integrator 3 has a function of condensing illumination light on a specific region where a secondary light source is to be formed. You may make it do.

Returning to FIG. 1, the illumination light IL transmitted through the reticle 13 is projected onto a wafer 19 as a substrate via a projection optical system 18 to project a pattern of the reticle 13 onto a projection magnification β (β is 1/4, 1 / 5) to form a reduced image. The wafer (wafer) 19 is, for example, a semiconductor such as silicon or SOI (s).
The substrate is a disk-shaped substrate such as silicon on insulator), on which a photoresist is applied. Hereinafter, the Z axis is taken parallel to the optical axis PAX of the projection optical system 18 (which coincides with the optical axis AX of the illumination optical system on the reticle 13), and X is set in a plane perpendicular to the Z axis and parallel to the plane of FIG. The description will be made by taking the axis and taking the Y axis perpendicular to the plane of FIG. In this case, the reticle 13
The upper illumination area has a slit shape elongated in the Y direction, and the scanning direction of the reticle 13 and the wafer 19 in the present example at the time of exposure is the X direction.

In this embodiment, the reticle 13 is held on a reticle stage 14, and the reticle stage 14 continuously moves the reticle 13 on the reticle base 15 in the X direction, and finely moves in the X direction, the Y direction, and the rotation direction. 1
3 is corrected. Moving mirror 16 fixed to end of reticle stage 14 and reticle stage drive system 1
The position of the reticle stage 14 is measured by the laser interferometer 7, and the reticle stage drive system 17 controls the operation of the reticle stage 14 based on the measured values and control information from the main control system 24.

On the other hand, the wafer 19 is held on a wafer stage 20 via a wafer holder (not shown), and the wafer stage 20 continuously moves the wafer 19 on the wafer base 21 in the X direction. The step moves in the X and Y directions. The position of the wafer stage 20 is measured by the movable mirror 22 fixed to the end of the wafer stage 20 and the laser interferometer in the wafer stage drive system 23, and based on the measured values and the control information from the main control system 24, Wafer stage drive system 23 controls the operation of wafer stage 20. Also, focus positions (positions in the optical axis PAX direction) at a plurality of measurement points on the wafer 19 measured by an auto focus sensor (not shown).
The wafer stage 20 continuously adjusts the surface of the wafer 19 to the image plane of the projection optical system 18 during the exposure by controlling the focus position and the inclination angle of the wafer 19 based on the information of.

At the time of exposure, when the exposure of one shot area on the wafer 18 is completed, the next shot area is moved to the scanning start position by the step movement of the wafer stage 20, and then the reticle stage 14 and the wafer stage 2 are moved.
0 is synchronously scanned in the X direction using the projection magnification β of the projection optical system 18 as the speed ratio, that is, the operation of scanning the reticle 13 and the shot area on the wafer 19 while maintaining the imaging relationship is a step.・ Repeated in the AND scan method. Thus, the pattern images on the reticle 13 are sequentially transferred to the respective shot areas on the wafer 19.

Next, the projection optical system of this embodiment will be described in detail. FIG. 2 is an end view along a section showing the internal configuration of the projection optical system 18 in FIG. 1. In FIG. 2, the projection optical system 18 including the catadioptric optical system A first imaging optical system for forming a primary image (intermediate image) I, and a secondary image of a reticle pattern is formed on a wafer 19 as a photosensitive substrate at a reduced magnification based on light from the primary image I. And a second imaging optical system.

The first image forming optical system includes, in order from the reticle side, a first lens group G1 having a positive refractive power, an aperture stop (not shown), and a second lens group G2 having a positive refractive power. Have been. The first lens group G1 includes, in order from the reticle side, a positive meniscus lens L11 having an aspheric convex surface facing the reticle side, a positive meniscus lens L12 having an aspheric convex surface facing the reticle side, and a positive meniscus lens L12 having a non-spherical convex surface facing the reticle side. And a positive meniscus lens L13 having a spherical concave surface. The second lens group G2 includes, in order from the reticle side, a biconcave lens L21 having a reticle side surface formed into an aspherical shape, a biconvex lens L22 having a reticle side surface formed into an aspherical shape, and a wafer side A positive meniscus lens L23 having an aspherical convex surface facing the lens and a positive meniscus lens L24 having an aspherical concave surface facing the wafer side.

On the other hand, the second image forming optical system has a surface reflecting surface R1 having a concave surface facing the wafer side in order from the reticle side, and a circular opening 61 having a center at the optical axis PAX at the center. A mirror M1, a lens component L2, and a sub-mirror M2 having a reflecting surface R2 provided on the lens surface on the wafer side are provided. A circular opening centered on the optical axis PAX is provided at the center of the sub-mirror M2. A part 62 is formed. The opening 61 of the main mirror M1 and the opening 62 of the sub-mirror M2 in this example correspond to the transmitting part of the reflecting member of the present invention. According to another aspect, the secondary mirror M
The lens component L2 and the lens component L2 form a back reflector, and the lens component L2 forms a refraction part of the back reflector. In this case, assuming that the imaging magnification of the first imaging optical system is β1 and the imaging magnification of the second imaging optical system is β2, for example, 0.7 <| β
It is desirable that the relationship 1 / β2 | <3.5 be satisfied.

All the optical elements (G1, G2, M1, L2, M2) constituting the projection optical system 18 are arranged in the lens barrel 30 along a single optical axis PAX. Primary mirror M1
Is disposed near the position where the primary image I is formed, the sub-mirror M2 is disposed close to the wafer 19, and the main mirror M1 and the lens component L2 are supported by the lens barrel 30 by convex portions M1a and M2a, respectively. Thus, in the present example, the image forming light flux composed of the illumination light IL from the pattern of the reticle 13 forms the primary image (intermediate image) I of the reticle pattern via the first image forming optical system, and Of the imaging light of the primary mirror M1
Is reflected by the sub-mirror M2 via an opening 61 provided around the optical axis PAX and a lens component L2. And
The light reflected by the sub-mirror M2 passes through the lens component L2, is reflected by the surface reflection surface R1 of the primary mirror M1, and is then reflected by the lens component L2.
A secondary image of the reticle pattern is formed at a reduced magnification on the surface of the wafer 19 through an opening 62 provided around the optical axis PAX in the secondary mirror M2. In the example of FIG. 2, the imaging magnification β1 of the first imaging optical system is 0.6249, the imaging magnification β2 of the second imaging optical system is 0.4000, and the projection magnification β from the reticle 13 to the wafer 19 is 0.25 (1/4
Times). An example of the detailed lens data of the projection optical system 18 shown in FIG.
-370143.

In this embodiment, all refractive optical members (lens components) constituting the projection optical system 18 are fluorite, that is, Ca
We are using a crystal of F _2. The oscillation center wavelength of the fluorine laser light (F ₂ laser light) as the illumination light for exposure is 157.6 nm, and the wavelength width is 157.6 nm ± 10.
Chromatic aberration is corrected for the light of pm, and various aberrations such as spherical aberration, astigmatism, and distortion are also corrected well. Further, in order to suppress a surface change of the reflection surface of the primary mirror M1 with respect to a temperature change and maintain a good imaging performance,
The support member that supports the surface reflection surface R1 of the primary mirror M1 is formed using a material having a linear expansion coefficient of 3 ppm / ° C. or less, for example, titanium silicate glass (Titanium Silicate Glass). As titanium silicate glass, for example, Corning ULE
(UltraLow Expansion: trade name) can be used.

In the projection optical system 18 of this embodiment, since all the optical elements constituting the catadioptric system are arranged along a single optical axis, chromatic aberration and the like can be reduced by using a reflecting member. In addition, it becomes possible to design and manufacture a lens barrel by using a technology on an extension of a conventional straight-tube type refracting system, and it is possible to achieve high precision without difficulty in manufacturing. That is,
In the present example, all the optical members constituting the first imaging optical system and the second imaging optical system are arranged along the same optical axis PAX.
It is held substantially sealed within the housing. The first
The lenses L11 to L24 constituting the imaging optical system are held in the first lens barrel, and the primary mirror M constituting the second imaging optical system
1 and the lens component L2 integrated with the sub-mirror M2 are held in a second lens barrel, and the first lens barrel and the second lens barrel are connected in series along the same optical axis PAX. Is also good.

Further, as illumination light (exposure beam) for exposure of the projection exposure apparatus of this embodiment, light having a wavelength of about 120 to 180 nm is used even in a vacuum ultraviolet region having a wavelength of about 200 nm or less. Lens L1 in 18
At present, materials of fluoride crystal materials such as fluorite (CaF ₂ , MgF ₂ , LiF, LaF ₃ , lithium calcium aluminum fluoride) having a high transmittance for light in this wavelength range are used for the materials 1 to L24 and the lens component L2. (Commonly known as Leica cuff crystals), and synthetic quartz glass doped with fluorine. Further, since the luminous flux in this wavelength range is strongly absorbed by oxygen, water vapor, hydrocarbon gas and the like existing in the general atmosphere, the concentration of these gases in the optical path through which the exposure beam passes is suppressed to about 10 ppm or less. There is a need.
Therefore, each optical member (lenses L11 to L24, primary mirror M
1. In the space (the space from the lens L11 to the lens component L2 in FIG. 2) which is an image forming optical path in the lens barrel 30 holding the sub mirror M2 and the lens component L2), the strongly absorbing gas is excluded. It is desirable to replace the gas with a gas (so-called inert gas) such as helium, neon, argon, or nitrogen having low absorption.

As described above, the projection optical system 18 has a primary mirror M1 having openings 61 and 62 (portions where no physical through-hole or reflection surface is formed) near its optical axis PAX.
Since the sub-mirror M2 is included, the image forming optical path emitted from an arbitrary point on the reticle 13 and reaching the wafer 19 has a center portion substantially shielded (hereinafter, referred to as "center shield"). I have. That is, the light ray passing through the central portion of the optical path is reflected by the primary mirror M
1. This is because the light passes through the openings 61 and 62 at the center of the sub-mirror M2 and is emitted outside the imaging optical path.

The position of the shielding portion in the total light flux changes depending on the position on the reticle 13. In this,
Since the characteristics of the image formed on the wafer 19 change according to the position on the reticle 13, if the fineness and integration of the pattern of the reticle 13 are further improved in the future, the amount of change in the image will be within the allowable range. May exceed. Therefore, in the present embodiment, the pupil plane PP of the projection optical system 18 formed between the reticle 13 and the primary image (intermediate image) I (that is, the reticle 13)
In the vicinity of an optical Fourier transform surface with respect to the pattern surface of (1), a circular light shielding member (hereinafter, referred to as a “central shielding portion”) for shielding an imaging light flux (imaging optical path) in a circular region centered on the optical axis PAX. CS) is arranged. Central shielding part CS
Can also be called a central shielding stop. The central shielding unit CS includes a primary mirror M1 and a secondary mirror M for each light beam passing through the pupil plane PP.
2 and a size that does not block the effective imaging light flux. Thereby, the central shielding portion of each light beam can be uniformly set as the center portion of the light beam,
There is no change in the image depending on the position.

FIG. 3 (a) shows an example of a method of supporting the center shielding portion CS. In FIG. 3 (a), three thin supporting members 26A, 26 are provided at the center of a thin annular metal plate 25.
A circular center shielding portion CS is arranged such that the center coincides with the optical axis PAX via B and 26C. Support member 26
Although A to 26C may be linear, it is more convenient to have a spiral shape as shown in FIG. 3A because it is possible to avoid adverse effects due to diffraction of the support members 26A to 26C themselves.

FIG. 3B shows another example of a method of supporting the center shielding portion CS. In FIG. 3B, a substrate 27 transparent to illumination light for exposure such as fluorite is used. The circular metal film formed on the surface of the central portion is the central shielding portion CS
It has been. In this case, it is necessary to change the shape of other lenses and the like in accordance with the insertion of the transparent substrate 27 into the pupil plane PP in FIG. Needless to say. The substrate 27 is made of the above-mentioned fluoride crystal material (CaF ₂ or the like) or synthetic quartz glass doped with impurities such as fluorine.

Further, a projection optical system 18 is provided on the pupil plane PP.
An aperture stop that determines the numerical aperture (NA) can be provided. Incidentally, the above-mentioned projection optical system is an optical system in which aberration is corrected very well by skillfully combining the characteristics of the reflecting mirror and the characteristics of the refractive lens. There is a problem in that the characteristics of the transferred image deteriorate. In particular, if the fineness and integration degree of the pattern of the reticle 13 are further improved in the future, the deterioration amount of the characteristics of the transferred image may exceed the allowable range.

The deterioration of the transferred image and a method of preventing the deterioration will be described below with reference to FIGS. FIG. 4 is an enlarged view of an example of a typical pattern generally formed on a reticle. In FIG.
A vertical pattern VP comprising an AND space pattern;
A horizontal pattern HP composed of a line-and-space pattern that is periodic in the Y direction, and oblique patterns OP2 and OP3 composed of a line-and-space pattern that is periodic in a direction rotated by 45 degrees with respect to the horizontal pattern HP are formed. Have been. On the actual reticle, such a vertical pattern VP, a horizontal pattern HP, and an oblique pattern OP
Patterns almost similar to OP2 and OP3 are formed in various combinations.

The process of projecting and exposing such a pattern is a process of forming an image (interference fringes) by causing each diffracted light generated by illuminating each periodic pattern with illumination light to interfere with each other on the wafer 19. Can be considered. From each periodic pattern, diffracted lights of the 0th order, ± 1st order, ± 2nd order,... Are generated. If the pattern is relatively fine,
Diffracted light dominant in image formation is limited to three luminous fluxes of 0 order and ± 1 order. This is because higher-order diffracted light has a diffraction angle larger than the numerical aperture of the projection optical system and cannot pass through the projection optical system.

The light quantity distributions shown in FIGS. 6A to 6D show images formed on the wafer by predetermined diffracted light from a periodic pattern on the reticle in the X direction.
In (d), the horizontal axis represents the position in the X direction on the wafer, and the vertical axis represents the light amount IM. First, the image I shown in FIG.
m1 is 0 of the diffracted light from the pattern on the reticle.
An image formed by three light fluxes of the next light IL (0) and the ± first-order lights IL (+1) and IL (-1) is shown, and the image Im1 has a high contrast. The image Im2 shown in FIG. 6B is composed of the zero-order light IL (0) and the + 1-order light IL (+1) (or −
And primary light IL (-1)), which also provides an image with sufficient contrast.

On the other hand, an image Im3 shown in FIG. 6C is an image formed only from the zero-order light IL (0). In this case, no interference fringes are formed and the image has no contrast. In the image Im4 shown in FIG. 6D, the 0th-order light is blocked,
This shows an image when only the ± first-order lights IL (+1) and IL (-1) reach the wafer, and the image Im4 has a contrast, but has a bright peak at the position 28 which should be a dark part. That is, it is an image having a half pitch of the original image, in other words, an image having twice the spatial frequency (hereinafter, referred to as a “double frequency image”).

Next, in FIG. 1, the pupil plane IP of the illumination optical system
When the illumination system aperture stop (σ stop) is switched to the predetermined aperture stop in FIG. 7, diffracted light that reaches the wafer 19 through the projection optical system 18 having the center shield shown in FIG.
FIG. 5 shows what order of diffracted light is included. FIG.
5A shows an illuminance distribution (secondary light source distribution) of the illumination light on a pupil plane IP in the illumination optical system. In FIG. 5A, one is a circular two-dimensional distribution distributed around the optical axis AX. The case where the secondary light source CI is used and the case where the secondary light source AI having an annular shape distributed in a range of a predetermined radius from the optical axis AX (a region surrounded by an inner circle and an outer circle) is used. The secondary light source CI
And the center of the secondary light source AI may be in the vicinity of the optical axis AX, and the shape of the secondary light source CI may be elliptical or polygonal. Similarly, the inner and outer shapes of the secondary light source AI are also necessarily circular. It is not necessary. These are an aperture stop 42 for small σ value and an aperture stop 43 for annular illumination in FIG.
Is equivalent to using. In addition, FIG.
In the pupil plane IP of the illumination optical system in (c) and (e), the outermost circumference INA represents the outer shape of the cross section of the illumination light having the maximum σ value.

When these illumination lights illuminate the reticle 13, the periodic patterns VP, HP, OP2 and OP2 shown in FIG.
OP3 generates diffracted light. FIG.
FIG. 7 is a diagram illustrating distributions of 0th-order and 1st-order diffracted light generated from the vertical pattern VP on the pupil plane PP of the projection optical system 18 corresponding to FIG. However, the period (pitch) P of each pattern
Is assumed to be relatively large with respect to the limit resolution of the projection optical system 18 as shown below.

P = 1.4 · λ / PNA (1) where λ is the exposure wavelength and PNA is the numerical aperture of the projection optical system. 5 (b), 5 (d), and 5 (f), the outermost circumference represents the aperture of the aperture stop (also called “PNA”) that defines the numerical aperture of the projection optical system 18. Since the pupil plane PP of the projection optical system and the pupil plane IP of the illumination optical system are both optical Fourier transform planes with respect to the pattern plane of the reticle 13, they are planes having an image forming relationship with each other. Therefore, the zero-order light CI0 from the secondary light source CI distributed in the center circular area on the pupil plane IP of the illumination optical system is also distributed in the circular area centered on the optical axis in the pupil plane PP of the projection optical system. On the other hand, +1
The first-order light CI1 is distributed at a position shifted by λ / P to the right from the 0th-order light CI0, and the -1st-order light CIM is
It is distributed at positions shifted by λ / P to the left from 0.
By the way, 0 distributed at the center of the pupil plane PP of the projection optical system
Since the next light CI0 is shielded by the center shield CS,
It cannot reach the wafer 19. And ± 1
Only the next-order diffracted lights CI1 and CIM reach the wafer 19.

For this reason, most of the image formed on the wafer 19 by the secondary light source CI distributed in the circular area becomes a double frequency image like the image Im4 in FIG.
This will degrade the fidelity of the image. Therefore, when the projection optical system 18 having a central shield as shown in FIG. 2 is used, the illuminance distribution (secondary light source shape) of the illumination light on the pupil plane IP of the illumination optical system is changed to the central portion (the illumination optical system). It is desirable that the intensity is weak or zero near the optical axis AX).

For example, if the shape of the secondary light source is limited only to the secondary light source AI distributed in the annular zone, the light amount near the optical axis AX on the pupil plane IP becomes zero. In this case, the 0th-order diffracted light from the vertical pattern VP is also distributed in the annular zone AI0 on the pupil plane PP of the projection optical system, and is not blocked by the center blocking portion CS. Similarly, the + 1st-order diffracted light is also distributed in the annular zone AI1,
The right half thereof is shielded by the aperture PNA (numerical aperture) of the aperture stop of the projection optical system, while the left half is shielded by the center shielding part CS.
The wafer reaches the wafer 19 except for a part blocked by the wafer 19. Since the left half of the + 1st-order diffracted light AI1 is the diffracted light of the illumination light emitted from the left half of the secondary light source AI, most of the illumination light illuminated from the left half of the secondary light source AI is Above, a high-contrast image is formed by interference between the 0th-order light and the + 1st-order light.

By the way, the above + 1st order diffracted light AI1 is
Part of the light is shielded by the central shield CS. Therefore, as for the diffracted light due to the illumination light from the partial area (secondary light source) DC in the left half of the secondary light source AI, only the zero-order light DC0 reaches the wafer 19, and Im3 in FIG. To form an image without contrast. Therefore, the image formed by the secondary light source DC lowers the contrast of the entire image, but the light amount ratio (area ratio) is small, and the adverse effect is small.

The right half of the secondary light source AI is also
Similarly, the 0th-order diffracted light AI0 and the -1st-order light (not shown) form a high-contrast image. In the above, only the vertical pattern VP on the reticle 13 has been described. However, the central light shielding portion CS and the secondary light source AI for annular illumination have the optical axis PA, respectively.
Since it is a circle and an annular zone centered on X and AX and has no directionality, it goes without saying that the same applies to the pattern in any direction.

Using this principle, an aperture stop 43 for annular illumination shown in FIG. 7 is installed in the illumination optical system by the aperture switching member 4 in FIG. 1, so that the projection optical system 18 having a central shield can be used. Good image fidelity is obtained when images of periodic patterns in all directions are projected. The inner diameter of the annular aperture 43a of the stop 43 is a size when projected on the pupil plane PP of the projection optical system 18 having an image forming relationship, and is desirably larger than the central shielding portion CS. Also,
In accordance with the pitch of the periodic pattern (average pitch in the reticle) and the like, another aperture stop 44 for annular illumination in FIG.
May be used.

When the direction of the pattern on the reticle 13 is limited, there is a method for further improving the fidelity of the transferred image. For example, when the pattern direction of the reticle 13 is limited to only the vertical pattern VP and the horizontal pattern HP, the secondary light sources S1 and S shown in FIG.
By using secondary light sources arranged at 90 ° intervals around the optical axis AX in a region at a predetermined distance from the optical axis AX as in 2, S3 and S4, the fidelity of the transferred image can be further improved. Can be. The secondary light source shape is such that, from the annular secondary light source AI in FIG. 5A, a light source unit DC that forms an image without contrast with respect to the vertical pattern VP, and an optical axis AX with respect to the light source unit DC. Are removed, and the upper and lower light sources that form an image without contrast for the horizontal pattern HP are also deleted.

Therefore, when the pattern direction is limited to the vertical direction (the arrangement direction is the X direction) and the horizontal direction (the arrangement direction is the Y direction), more excellent imaging characteristics are obtained. FIG. 5D shows the distribution of the diffracted light by the illumination light from the secondary light source S1 on the pupil plane PP of the projection optical system at this time.
In FIG. 5D, the zero-order light S10 and the vertical pattern V
P, each + 1st-order diffracted light S1V, S1 from the horizontal pattern HP
H is the pupil plane PP almost unobstructed by the central shield CS.
And reaches the wafer 19. Accordingly, from the illumination light from the secondary light source S1, a high-contrast image like the image Im2 in FIG. 6B is formed. of course,
The same applies to the other secondary light sources S2, S3, S4.

However, the oblique patterns OP2 and OP in FIG.
For a pattern that is periodic in the oblique direction such as 3, most of the respective first-order diffracted lights S12 and S13 are shielded by the central shielding portion CS or the aperture PNA of the aperture stop.
(Numerical aperture). Therefore, improvement in the imaging characteristics of the oblique pattern cannot be expected much. Using this principle, the aperture switch 45 for the modified illumination shown in FIG. 7 is installed in the illumination optical system by the aperture switching member 4 in FIG. 1, and the secondary light sources S1 to S4 shown in FIG. By using
Even with the use of the projection optical system 18 having a central shield, good pattern fidelity can be obtained, particularly for a periodic pattern in the vertical and horizontal directions. At this time, each secondary light source S1 shown in FIG.
1/2 of the distance between S4 and S4, for example, the half value w of the interval between the secondary light sources S1 and S2 in FIG. 5C is the size projected on the pupil plane PP of the projection optical system 18 in an image forming relationship. , It is desirable to make it larger than the radius of the central shielding part CS.

In the above embodiment, the shape of each of the secondary light sources S1 to S4 is such that a part thereof is cut out from the ring as shown in FIG. 5C. The shape may be a substantially square shape as proposed in Japanese Patent Application Laid-Open No. 4-225514, or a shape that shields a region within the width of the half value w from the circular region.

Further, in order to obtain good imaging characteristics even for the oblique patterns OP2 and OP3, the shape of the secondary light source is set at an equal angle around the optical axis AX as shown in FIG. It is preferable to use eight secondary light sources E1 to E8 arranged at intervals. This is the secondary light sources S1 to S4 shown in FIG. 5C optimized for the vertical pattern and the horizontal pattern, and their respective central parts are further deleted. The distribution of the secondary light sources is In a region at a predetermined distance from the axis AX, the light is distributed at intervals of 45 degrees around the optical axis AX.

Of the secondary light sources, secondary light sources E1 and E2
FIG. 5F shows the distribution of the diffracted light by the illumination light from the pupil plane PP of the projection optical system. The 0th-order lights E10 and E20 pass through the pupil plane, and are the first-order diffracted lights E by the vertical pattern VP.
1V, E2V, and first-order diffracted light E by the horizontal pattern HP
Most of 1H and E2H also transmit through the pupil plane. Further, most of the first-order diffracted lights E12 and E22 from the oblique pattern OP2 are transmitted through the pupil plane.

On the other hand, of the + 1st-order diffracted light from the oblique pattern OP3, the + 1st-order diffracted light E23, which is the light from the secondary light source E2, passes through the pupil plane, but the + 1st-order diffracted light E13, which is the light from the secondary light source E1. Is the aperture stop (numerical aperture) PNA
Light is blocked by the However,-from the secondary light source E1
Since the first-order diffracted light E14 passes through the pupil plane, the first-order diffracted light E1 is eventually divided into the 0th-order light and the ± 1st-order diffracted light for the patterns of the illumination light from the secondary light sources E1 and E2 in the vertical, horizontal, and oblique directions. One always reaches the wafer and forms an image with high contrast as shown in FIG.

Using this principle, the aperture stop 46 shown in FIG. 7 is installed in the illumination optical system by the stop switching member 4 shown in FIG. 1, and the secondary light sources E1 to E8 shown in FIG. 5E are used. As a result, even when the projection optical system 18 having the center shield is used, it is possible to realize a projection exposure apparatus having good pattern fidelity, particularly with respect to the periodic pattern in the vertical, horizontal, and oblique 45-degree directions. At that time, each secondary light source E1
The distance between the adjacent secondary light sources in E8 is a length when the image is projected on the pupil plane PP of the projection optical system 18 having an image-forming relationship, and is preferably larger than the diameter of the central shielding portion CS.

In the above embodiment, the shape of each of the secondary light sources E1 to E8 is such that a part thereof is cut out from the annular zone as shown in FIG. 5 (e). It may be arbitrary and may be square or circular. In order to increase the illuminance of the illumination light on the wafer 19, shorten the exposure time on the wafer 19, and increase the throughput of the exposure apparatus, the illumination light is applied to these eight secondary light sources E1 to E8. Must be efficiently condensed. As this method, for example, a two-stage fly-eye lens arranged in series as the optical integrator 3 in FIG. 1 is used, and the first-stage (light source side) fly-eye lens is replaced with 8n lens elements (n Is a natural number).
The stage fly-eye lens may be composed of eight fly-eye lenses separately arranged at eight positions. In this configuration, the surface on the exit side of each lens element of the first-stage fly-eye lens is tapered to have a refraction effect, and illumination light is applied to the second-stage fly-eye lenses arranged at the eight positions. By converging light, high illumination efficiency can be obtained.

In the above embodiment, the illumination light is
Although it is assumed that it is distributed only at the position of each predetermined secondary light source,
Even if some illumination light is distributed on a portion other than the position of each secondary light source on the pupil plane IP of the illumination optical system, it does not matter much. In short, the intensity distribution of the secondary light source at each designated position Is larger and smaller at other positions, the effect of the present invention can be obtained.

In the above embodiment, a fly-eye lens is used as the optical integrator 3, but instead of this, a rod (quadrangular prism-shaped glass) is used.
Can also be used. In this case, no secondary light source is formed on the exit surface of the optical integrator 3,
Also, the exit surface of the rod is no longer the pupil plane of the illumination optical system,
Although it is conjugate with the pattern surface of the reticle 13, the iris switching member 4 similar to FIG. 1 is provided with respect to the pupil plane IP of the illumination optical system formed between the exit surface of the rod and the reticle 13.
By providing a desired illumination system aperture stop (σ stop), good pattern fidelity can be obtained even when the projection optical system 18 is used. Alternatively, since the entrance surface of the rod is substantially arranged on the pupil plane of the illumination optical system, the aperture switching member 4 may be provided close to the entrance surface.

Alternatively, good pattern fidelity can be obtained by providing the above-mentioned stop or light-condensing member for determining the shape of the secondary light source on an optical Fourier transform surface with respect to the reticle pattern surface closer to the light source than the rod. Degree.
The fly-eye lens forms a large number of light source images on its exit-side focal plane (the pupil plane of the illumination optical system), and the surface light source composed of the large number of light source images serves as the secondary light source AI. A plurality of virtual images formed on the surface side correspond to a secondary light source.

In the above-described embodiment, the intensity distribution of the illumination light on the pupil plane (Fourier transform plane) of the illumination optical system, that is, the shape and size of the secondary light source can be changed by using the aperture switching member 4. However, for example, the exposure light source 1 and the optical
At least one optical element disposed between the optical integrator 3 and the integrator 3 can be moved in the optical axis direction, that is, a zoom optical system, and the intensity distribution of the illumination light on the incident surface of the optical integrator 3 can be changed. Good. Thereby, in the fly-eye lens, its exit side focal plane, in the rod, the pupil plane of the illumination optical system where its entrance plane is arranged, or the exit plane of the optical integrator 3 and the reticle 1
2, the size of the secondary light source on the pupil plane of the illumination optical system, that is, the coherent factor (σ) of the illumination optical system
Value) can be changed continuously and without loss of light quantity.

Further, a pair of conical prisms (axicons) is disposed closer to the light source or the optical integrator than the at least one optical element, and the distance between the pair of axicons in the optical axis direction is adjusted. The illumination light on the incident surface of the integrator 3 may be configured to be changeable into an annular shape in which the intensity distribution is higher outside the center than outside the center. As a result, the exit-side focal plane of the fly-eye lens, the pupil plane of the illumination optical system where the entrance plane is located in the lot, or the illumination optical system set between the exit plane of the optical integrator 3 and the reticle 12 It is possible to change the intensity distribution (shape and size of the secondary light source) of the illumination light on the pupil plane, and to greatly reduce the light quantity loss of the illumination light due to the change of the illumination condition. , High throughput can be maintained.

By using the above-mentioned zoom optical system and a pair of axicons, not only switching between normal illumination and annular illumination, but also the outer diameter, inner diameter, and annular diameter of the secondary light source in annular illumination. At least one of the ratios (the ratio between the outer diameter and the inner diameter) can be changed continuously and without loss of light amount. Also, a plurality of secondary light sources decentered from the optical axis of the illumination optical system, for example, four or eight shown in FIGS. 5C and 5E.
In order to form two secondary light sources, an annular secondary light source is formed on the pupil plane (Fourier transform plane) of the illumination optical system by using the above-described zoom optical system and a pair of axicons in combination.
An optical element (light-shielding plate or light-attenuating plate) that partially blocks or diminishes the aperture stop or the annular secondary light source shown in FIG.
May be arranged on the pupil plane of the illumination optical system or in the vicinity thereof. In this case, it is possible to greatly reduce the light amount loss as compared with the case where a plurality of secondary light sources are formed only by the aperture switching member 4.

In the illumination optical system and the projection optical system 18 according to the above-described embodiment, after the respective optical members are arranged in the supporting member or the lens barrel in a predetermined positional relationship, and the adjustment is performed, the lens barrel becomes unfit. Assembled by installing on the column shown. Along with the assembly adjustment, the stage system and the laser interferometer are assembled and adjusted, and the respective components are electrically, mechanically or optically connected to assemble the projection exposure apparatus of the above embodiment. Can be The work in this case is desirably performed in a clean room where the temperature is controlled. The wafer exposed by the above-mentioned projection exposure apparatus undergoes a developing step, a pattern forming step, a bonding step, and the like, whereby devices such as semiconductor elements are manufactured.

In the above embodiment, the projection optical system 18 shown in FIG. 2 is used. However, the present invention is not effective only when such a projection optical system 18 is used. Of course, the present invention is also effective when a projection optical system having another configuration is used. However,
The present invention is particularly effective when having a projection optical system including an optical member having an opening (transmission part) formed near the optical axis.

In the projection optical system 18 shown in FIG.
And the lens component L2 constitute a back surface reflecting mirror. For example, a sub mirror M2 may be disposed separately from the lens component L2, that is, the sub mirror M2 may be a front surface reflecting mirror. It is disclosed in JP-A-11-66769. Further, in the projection optical system 18 of FIG. 2, the primary mirror M1 and the secondary mirror M2 are arranged on the image plane side (wafer side) with respect to the primary image (intermediate image) I, for example, as disclosed in JP-A-10-104513. As disclosed, a catadioptric system in which a pair of reflecting mirrors (corresponding to a primary mirror M1 and a secondary mirror M2) is arranged on the object plane side (reticle side) of the position where the intermediate image I is formed, or US Pat. As disclosed in Japanese Patent No. 5650877 or No. 5559338, a catadioptric system that does not form the intermediate image I may be used.

The projection optical system 18 shown in FIG. 2 is telecentric on both sides of the object plane and the image plane, but may be telecentric only on the image plane side. The optical element is divided and stored in three or more lens barrels, and the plurality of lens barrels are connected so that the inert gas purge is maintained, or the plurality of lens barrels is stored in another lens barrel. (That is, the projection optical system 18 is a double lens barrel). The radius ratio between the central shielding portion CS of the projection optical system 18 and its pupil plane is preferably about 20% or less. For example, the line width of the pattern to be transferred or the required field of the projection optical system 18 Depending on the size, the radius ratio may exceed 20%. Since the size of the central shielding portion CS, that is, the above-described radius ratio is determined according to the field size of the projection optical system 18, the radius ratio is, for example, about 20% or less.
When a projection optical system having a relatively small field size is used, a circuit pattern having a large area may be formed on a substrate (wafer) by using a step-and-stitch method.

When the radius of the central shielding portion is about 15% or less of the pupil radius (corresponding to the numerical aperture NA) of the projection optical system, the effect of the central shielding portion on the imaging characteristics is small. The necessity of applying the modified illumination such as is low. On the other hand, when the radius of the central shielding portion is about 20% or more of the pupil radius of the projection optical system, the adverse effect of the central shielding portion becomes large, so that the modified illumination according to the present invention is effective.

However, when the radius of the central shielding portion is further increased, the area of the deformed light source of the present invention is reduced.
Since there is a possibility that the light quantity and the illuminance uniformity may be reduced, it is desirable that the radius of the central shielding portion be suppressed to about 25% or less of the pupil plane of the projection optical system. Also, the present invention uses ArF as the exposure light.
The light of the longest wavelength in the vacuum ultraviolet region, such as excimer laser light (wavelength 193 nm), or the light in the far ultraviolet region, such as KrF excimer laser light (wavelength 248 nm), is used for the projection optical system. In the case where a reflection member is partially included, the same can be applied.

However, the present invention exerts its effect to the maximum only in a wavelength range in which the types of glass materials having a high transmittance for a refraction member (such as a lens) in a projection optical system are limited, ie, a vacuum ultraviolet region. In particular, this is a case where light in a wavelength range of about 120 to 180 nm is used as exposure light. As a light source of the exposure light in this wavelength range, in addition to the fluorine laser of the above embodiment, an Ar ₂ (argon dimer) laser having a wavelength of about 120 to 130 nm, a KrAr laser having a wavelength of about 146 nm, other gas lasers, And a harmonic conversion element for generating a harmonic of another laser beam.

As an example, an infrared or visible single wavelength laser oscillated from a DFB semiconductor laser or a fiber laser is doped with, for example, erbium (or both erbium (Er) and ytterbium (Yb)). Harmonics amplified by a fiber amplifier and wavelength-converted to ultraviolet light using a nonlinear optical crystal may be used as illumination light for exposure. For example, if the oscillation wavelength of a single-wavelength laser is in the range of 1.544 to 1.553 μm, 193
8th harmonic within the range of 〜194 nm, that is, ultraviolet light having substantially the same wavelength as that of the ArF excimer laser is obtained, and when the oscillation wavelength is within the range of 1.57 to 1.58 μm, 157
The 10th harmonic within the range of １５158 nm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser is obtained.

It is to be noted that the present invention uses the exposure light having a wavelength of 5-1.
The present invention can be applied to a case where extreme ultraviolet light (EUV light) such as soft X-ray of about 5 nm is used, and a case where a projection optical system including a reflection system is used. Further, in the above embodiment, the present invention is applied to a step-and-scan type projection exposure apparatus. However, it is apparent that the present invention can be applied to a batch exposure type projection exposure apparatus such as a stepper. .

The present invention is not limited to the above-described embodiment, but can take various configurations without departing from the spirit of the present invention.

[0073]

According to the present invention, when a projection optical system having a configuration in which a part of an image forming light beam is practically shielded is used, the illuminance distribution of the exposure beam from the illumination optical system is substantially reduced. Because of the optimization, it is possible to reduce the adverse effect on the image forming characteristics due to the shielding of the image forming light beam, and to suppress a decrease in the fidelity of the transferred pattern or a decrease in the contrast of the projected image. There is.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a projection exposure apparatus according to an example of an embodiment of the present invention.

FIG. 2 is an end view along a section showing a configuration of a projection optical system 18 in FIG.

3A is an enlarged plan view showing an example of a method of supporting a center shielding portion CS in FIG. 2, and FIG.
It is an expanded side view which shows the other example of the support method of FIG.

FIG. 4 is an enlarged plan view showing a typical periodic pattern formed in a pattern region of a reticle.

FIG. 5 shows the distribution of secondary light sources on the pupil plane of the illumination optical system in the projection exposure apparatus according to the embodiment, and the distribution of imaging light flux (diffracted light) passing through the pupil plane of the projection optical system correspondingly. FIG.

FIG. 6 is a diagram illustrating a relationship between an example of an effective combination of diffracted lights and an image formed by the combination of the diffracted lights.

FIG. 7 is a diagram showing a plurality of illumination system aperture stops (σ stops) formed on the aperture switching member 4 of FIG. 1;

[Explanation of symbols]

1: Exposure light source, 3: Optical integrator, 4
... Aperture switching member, 8 ... Field stop, 13 ... Reticle,
18: Projection optical system, 19: Wafer, 24: Main control system, 4
2 to 46: aperture stop (σ stop), CS: center shielding portion, 6
1, 62: opening, M1: primary mirror, M2: secondary mirror, VP: vertical pattern, HP: horizontal pattern, OP2, OP3: diagonal pattern

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H087 KA21 LA01 NA02 NA04 PA07 PA17 PB07 QA02 QA06 QA12 QA21 QA25 QA32 QA41 QA45 RA03 RA12 RA13 RA26 RA31 RA32 TA01 TA03 TA04 UA00 UA02 UA03 UA04 5F046 BA04 BA05 CA03 CB04 DA07 DB04 DC12 9A001 BB05 HH34 JJ61 KK16 KK54

Claims (8)

[Claims] 1. A projection exposure method for illuminating a mask with an exposure beam from an illumination optical system and transferring a pattern of the mask onto a substrate via a projection optical system, wherein each of the projection optical systems A region including the optical axis of the optical system or a region in the vicinity of the optical axis, two reflective members each having a reflective surface on which a transmission portion through which the exposure beam passes is formed; and a pattern of the mask of the illumination optical system. The illuminance distribution of the exposure beam on the optical Fourier transform plane with respect to the surface is set to be weak in a region including the optical axis of the illumination optical system or in a region near the optical axis and strong in an outer peripheral portion distant from the optical axis. And a projection exposure method. 2. A projection exposure apparatus which illuminates a mask with an exposure beam from an illumination optical system and transfers a pattern of the mask onto a substrate via a projection optical system. A region including the optical axis of the optical system or a region in the vicinity of the optical axis, two reflective members each having a reflective surface on which a transmission portion through which the exposure beam passes is formed; and a pattern of the mask of the illumination optical system. The illuminance distribution of the exposure beam on the optical Fourier transform plane with respect to the surface is set to be weak in a region including the optical axis of the illumination optical system or in a region near the optical axis and strong in an outer peripheral portion distant from the optical axis. A projection exposure apparatus, comprising: 3. The illuminance adjusting member increases an illuminance distribution of the exposure beam on the optical Fourier transform surface of the illumination optical system in an annular zone surrounding the optical axis of the illumination optical system. 3. The projection exposure apparatus according to claim 2, wherein the setting is performed. 4. The illuminance adjusting member arranges illuminance distribution of the exposure beam on the optical Fourier transform surface of the illumination optical system at substantially equal angular intervals around an optical axis of the illumination optical system. 3. The projection exposure apparatus according to claim 2, wherein the intensity is set to be stronger in a plurality of the four or more areas. 5. A projection exposure apparatus for illuminating a mask with an exposure beam from an illumination optical system and transferring a pattern of the mask onto a substrate via a projection optical system, wherein the pattern of the mask of the projection optical system is provided. A part of an imaging optical path from an arbitrary point on the mask to an imaging position on the substrate near or at an optical Fourier transform plane with respect to the plane, and the illumination optics The illuminance distribution of the exposure beam on the optical Fourier transform surface with respect to the pattern surface of the mask of the system is strongly enhanced in eight or more regions arranged at substantially equal angular intervals around the optical axis of the illumination optical system. A projection exposure apparatus provided with an illuminance adjustment member for setting the brightness of the projection exposure apparatus. 6. The projection optical system includes a reflecting member having an opening formed in a part of a spherical reflecting surface, and an image forming optical path passing through a central portion of the opening of the reflecting member is substantially blocked. 6. The projection exposure apparatus according to claim 5, wherein the exposure is performed. 7. The projection optical system has a reflection surface in which a transmission portion through which the exposure beam passes is formed in a region including the optical axis of the projection optical system or in a region near the optical axis.
7. The light emitting device according to claim 5, further comprising: two reflecting members.
The projection exposure apparatus according to claim 1. 8. A projection exposure method according to claim 1,
A device manufacturing method including a step of transferring a device pattern onto a workpiece.