JPH1064790A - Projection aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection aligner which can suppress fluctuations in high order spherical aberration when zonal illumination or modified illumination is carried out. SOLUTION: Apart from a light source unit 1 for light exposure, another light source unit 2 is provided for emitting illumination light IL2 having such wavelengths that will not be sensitive to photoresist on a wafer 13. Provided on an optical path of illumination light IL1 is a modified mirror 5 of mirrors 6A and 6B having reflecting surfaces tilted toward a reticle 10. The illumination light IL1 for light exposure from the light source unit 1 is passed through a zonal region around the modified mirror 5; while the illumination light IL2 for non-exposure is reflected by the reflecting surfaces of the modified mirror 5 to be directed toward the reticle 10 and a projection optical system 12. With the illumination light IL1 and IL2, a lens in the vicinity of a pupil surface of the projection optical system 12 can be illuminated with a uniform illumination distribution.

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 semiconductor device, a liquid crystal display device, an image pickup device (CCD or the like), a thin film magnetic head, or the like by using a photolithography process to form an image of a pattern on a mask on a photosensitive substrate. The present invention relates to a projection exposure apparatus that is used for performing exposure to an object, and is particularly suitable for application to a projection exposure apparatus that performs annular illumination or the like or uses a center-shielded pupil filter.

[0002]

2. Description of the Related Art Conventionally, for example, when a semiconductor device is manufactured, a wafer on which a photoresist as a photosensitive substrate is applied by using a projection optical system to project a pattern image of a reticle (or a photomask or the like) as a mask. Or, a projection exposure apparatus such as a stepper for transferring onto a glass plate or the like is used. In these projection exposure apparatuses, in order to expose a pattern with the highest possible integration on a wafer, illumination light having the shortest possible wavelength is used as exposure light, and the numerical aperture (NA) of the projection optical system is increased to transfer the pattern. Efforts have been made to increase the resolution of such patterns.

However, if the numerical aperture of the projection optical system is simply increased, the depth of focus becomes too narrow. Therefore, a certain depth of focus or more is secured without depending on the numerical aperture, and high resolution is obtained. As a method, an illumination method of illuminating the reticle with the exposure light inclined has been developed. This illumination method includes annular illumination in which the shape of a secondary light source in an illumination optical system is annular and so-called deformed illumination in which the shape of the secondary light source is a plurality (for example, four) of small light sources decentered from the optical axis. Etc. According to such an illumination method, the resolution of the projection optical system is improved even with the same exposure wavelength and the same numerical aperture of the projection optical system. Also, a method has been developed in which a pupil filter having a ring shape or the like is arranged on the pupil plane of the projection optical system to improve the resolution by so-called “super-resolution”.

[0004]

In the above prior art, an illumination method for illuminating a reticle with exposure light which is uniformly distributed around a light beam perpendicularly incident on the reticle without using annular illumination or the like. According to the method, an image of the pattern is formed on a wafer mainly by three light beams of the 0th-order diffracted light, the + 1st-order diffracted light, and the -1st-order diffracted light that have passed through the reticle pattern. The lens is almost uniformly illuminated both at the center and at the periphery. In addition, even when an annular pupil filter that blocks a central portion is not arranged on the pupil plane of the projection optical system under a normal illumination method, the lens near the pupil plane of the projection optical system is uniformly illuminated. . In such an illuminated state, the temperature at the center of the lens mainly increases,
Thermal deformation and a change in the refractive index, which are functions of the second order or less with respect to the position, mainly occur, and only the movement of the Gaussian image plane occurs as the main aberration fluctuation near the optical axis. Therefore, there was little possibility that high-order spherical aberration fluctuation of the projection optical system would occur.

However, when illumination is performed by the annular illumination or the modified illumination method, when the illumination light for exposure that has passed through the pattern of the reticle is mainly the 0th-order diffracted light and the 1st-order diffracted light, the pattern is formed on the wafer. Therefore, when there are many patterns close to the critical line width of the resolution of the projection optical system, the amount of light transmitted near the optical axis of the projection optical system is extremely small as compared with the peripheral portion. Also, even if a pupil filter that shields the vicinity of the optical axis is arranged on the pupil plane of the projection optical system,
The amount of light rays passing near the optical axis of the lens disposed closer to the wafer than the pupil plane is extremely small as compared with the peripheral part.

[0006] When the distribution of the irradiation energy to the lens of the projection optical system becomes non-uniform as described above, a phenomenon occurs in which the peripheral portion of the lens mainly absorbs heat and the temperature rises, and the central portion does not rise. In proportion to such a temperature rise, the refractive index of the lens partially fluctuates or the lens is thermally deformed, so that a higher-order aspherical surface than the second-order and a corresponding refractive index distribution are newly added. It is formed. For this reason, in a portion near the optical axis of the projection optical system, there is a disadvantage that the irradiation of the exposure light causes not only the movement of the Gaussian image plane but also a new high-order spherical aberration fluctuation.

[0007] In view of the above, the present invention provides a high-order spherical surface of a projection optical system when performing exposure using annular illumination, modified illumination, or the like, or using a pupil filter that blocks light near the optical axis. It is an object of the present invention to provide a projection exposure apparatus capable of obtaining high resolution while suppressing aberration fluctuation.

[0008]

A first projection exposure apparatus according to the present invention, as shown in FIG. 1, for example, forms an image of a pattern on a mask (10) under exposure illumination light (IL1). A projection optical system (12) for projecting on a photosensitive substrate (13);
A light source (including a secondary light source) distributed in a region decentered from the optical axis (AX) on a pupil plane of the projection optical system, that is, a plane conjugate with the optical Fourier transform plane (PS) with respect to the pattern plane of the mask (10). ) To illuminate the mask (10) using the exposure illumination light (IL1) from (1).
3, 9), the illumination light (IL) in a wavelength range insensitive to the photosensitive substrate (13).
An auxiliary illumination system (2) is provided to irradiate the area (2) on the pupil plane (PS) of the projection optical system (12) through which the illumination light (IL1) for exposure does not pass.

According to the first projection exposure apparatus of the present invention, on the plane conjugate with the pupil plane (PS) of the projection optical system (12), a light source distributed in a region decentered from the optical axis (AX) is used. Using the illumination light (IL1) for exposure means that an annular illumination method or a modified illumination method is used. At this time, the lens near the pupil plane of the projection optical system (12) is mainly illuminated by the illumination light (IL1) for exposure in a region decentered from the optical axis. can get.
Further, the pupil plane (P) of the projection optical system (12) is
S) a region on which the illumination light for exposure (IL1) does not pass;
That is, since the area near the optical axis is also illuminated with the non-photosensitive illumination light (IL2) on the photosensitive substrate, the illuminance distribution on the lens close to the pupil plane (PS) of the projection optical system (12) becomes uniform, Higher order fluctuation components in the thermal deformation of the lens and changes in the refractive index are reduced. For this, the non-photosensitive illumination light (I
L2) needs to be absorbed by the lens of the projection optical system (12) or the coating film of this lens with the same absorptivity as the illumination light (IL1) for exposure. Since the fluctuation of the spherical aberration of the lens is proportional to the thermal deformation and the change of the refractive index of the lens, the fluctuation of the higher-order spherical aberration of the projection optical system (12) is suppressed. However, the illumination light (IL2) from the auxiliary illumination system (2)
Has no effect on the image transferred on the photosensitive substrate (13) because it is non-photosensitive.

In this case, the illumination optical system uses the illumination light (IL1) for exposure from an annular light source or a plurality of light sources located eccentrically with respect to the optical axis to the mask (1).
It is preferable to illuminate 0). This means an illumination method using so-called annular illumination or deformed illumination, whereby a high resolution can be obtained. Further, the illumination optical system has an optical integrator (24) for making the illuminance distribution of the exposure illumination light (IL1) uniform, and between the optical integrator and the mask (10). ,
Auxiliary light introducing members (4, 6A to 6D, and 4A) for guiding illumination light (IL2) from the auxiliary illumination system (2) to the mask (10).
7A, 7B). Thereby, the illumination light (IL1) for exposure and the illumination light (IL2) can be easily combined.

A second projection exposure apparatus according to the present invention, for example, as shown in FIG.
When the image of the pattern on the mask (10) is projected on the photosensitive substrate (13) via the projection optical system (12) under B), the pupil plane (PS) of the projection optical system (12) In the projection exposure apparatus using the imaging light flux passing through the area decentered from the optical axis (AX), the illumination light (IL1) for the exposure is used.
B) and the combined illumination optical system (1B, 42, 2B, 4B, 7A, 8) that guides the illumination light (IL2B) that is insensitive to the photosensitive substrate (13) to the pupil plane (PS) of the projection optical system.
A), and illumination light () that is arranged on the pupil plane (PS) of the projection optical system (12) and is non-photosensitive to the photosensitive substrate (13) in a region other than a region decentered from the optical axis. IL
2B), and an optical member (5B) having wavelength selectivity for passing only the photosensitive substrate side.

According to the second projection exposure apparatus of the present invention, the optical axis (A) on the pupil plane (PS) of the projection optical system (12).
Since an imaging light flux passing through a region decentered from X) is used, high resolution is obtained substantially equivalent to the use of a pupil filter of a central light shielding type. In this case, the illumination light (IL1B) for exposure passes only through an annular region or the like by the optical member (5B), and the illumination light (IL2B) that is non-photosensitive to the photosensitive substrate (13). It passes through an area other than the area decentered from the optical axis. Therefore, the projection optical system (1)
The lens in the vicinity of the pupil plane (PS) of 2) has two illumination lights (I
L1B, IL2B), the light is irradiated with a uniform illuminance distribution, so that higher-order fluctuation components in the thermal deformation of the lens and changes in the refractive index are reduced, and the higher-order spherical aberration fluctuation is also reduced. In addition, the non-photosensitive illumination light (IL2B) is applied to the photosensitive substrate (13).
The above projected image is not affected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a projection exposure apparatus according to the present invention will be described below with reference to FIGS. In this embodiment, the present invention is applied to a stepper type projection exposure apparatus that projects a pattern on a reticle onto each shot area on a wafer via a projection optical system.

FIG. 1 shows a schematic configuration of the projection exposure apparatus of the present embodiment. As shown in FIG.
One light source unit (two light source units 1 and 2 appear in FIG. 1) is provided. During exposure, the first light source unit 1 applies a photosensitive wavelength λ1 to the photoresist on the wafer 13.
And the second light source unit 2 and a third light source unit (not shown) emit non-photosensitive illumination light IL2 having a wavelength λ2 to the photoresist on the wafer 13. Illumination light emitted from the light source 21 composed of a mercury lamp of the light source unit 1 is converged on the second focal point by the elliptical mirror 22, becomes divergent light, enters an interference filter or the like (not shown), and is emitted by the interference filter. For example, illumination light IL1 of i-line (wavelength 365 nm) is extracted. Next, the illumination light IL1 is converted into a parallel light beam by the input lens 23 and is incident on a fly-eye lens 24 as an optical integrator.
A secondary light source is formed on each exit surface of each lens element of the fly-eye lens 24, and these secondary light sources form a surface light source. A plurality of switchable aperture stops 26A to 26C (see FIG. 2A) for adjusting the size of the surface light source are arranged on the exit surface of the fly-eye lens 24. These aperture stops 26A to 26C are fixed to a turret-shaped disk 25, and the disk 25 is
By rotating at 5A, a desired aperture stop can be set on the exit surface of the fly-eye lens 24.

FIG. 2A is a plan view for explaining a specific configuration of the aperture stop on the disk 25 of FIG. 1. In FIG. 2A, three aperture stops 26A to 26A are shown. 26C is fixed at equal angular intervals around the turret disk 25. The first aperture stop 26A has a circular aperture used for normal illumination, and the second aperture stop 26B has a small circular aperture used for illumination with a small coherence factor (σ value). Have. The third aperture stop 26C has a large circular aperture, and in this example, annular illumination,
Alternatively, when performing modified illumination, the third aperture stop 26C is set on the exit surface of the fly-eye lens 24. That is, at the time of normal annular illumination, the annular aperture stop 26 shown in FIG.
D is used, and an aperture stop 26E having four small apertures arranged around the optical axis shown in FIG. However, in this example, the aperture stop 26D and the like are also used substantially by the later-described deformable mirror 5 and the like. In FIG. 1, the third aperture stop 26C is arranged on the optical path of the illumination light IL1.

The illumination light IL1 that has passed through the aperture stop 26C
Is transmitted through the first relay lens 27, and the illumination range is defined by a field stop (reticle blind) 28. The illumination light IL1 whose illumination range is defined is emitted from the light source unit 1 and passes through the second relay lens 3 to the optical axis A of the illumination optical system.
A deformed mirror 5 composed of four mirrors 6A to 6D (two mirrors 6A and 6B are shown in FIG. 1) arranged in a concave pyramid shape on the side of the second relay lens 3 with X as the center.
Pass around. The reflecting surfaces of the four mirrors of the deformable mirror 5 face outward, and are approximately 4 with respect to the optical axis AX of the illumination optical system.
It is inclined at 5 °. Further, the upper surface of the deformable mirror 5 is arranged at a position conjugate with the arrangement surface of the aperture stop 26C. The illumination light IL1 that has passed around the deformable mirror 5 enters the reticle 10 via the condenser lens 9.

FIG. 3A shows the deformed mirror 5 of FIG. 1 viewed from the reticle 10 side. In FIG. 3A, the mirrors 6A to 6D have the same shape and the optical axis of the illumination optical system. They are arranged closely so as to form a quadrangular pyramid having AX as a vertex. Further, the outer shape 17 of the bottom surface of each of the mirrors 6A to 6D forms a single circumference centered on the optical axis AX as a whole. The illumination light IL1 is configured to pass through a ring-shaped area 15 between the outer shape 17 and the outer periphery 16 of the image of the aperture of the aperture stop 26C in FIG.
That is, the deformable mirror 5 of the present example also serves as a ring-shaped aperture stop.

Returning to FIG. 1, the deformable mirror 5 can be retracted outside the optical path of the illumination light IL1 by the retractable exchange device 8, and
It is configured so that it can be replaced with another deformable mirror. Next, the second light source unit 2 includes a non-exposure light source, a lens system that emits a light beam from the light source at a predetermined divergent angle, and the like. Then, the illumination light IL2 which is non-photosensitive to the photoresist emitted from the light source unit 2 disposed at the upper left of the reticle 10 is converted into a parallel light flux by the relay lens 4, and a part of the illumination light IL2 is aligned with the optical axis AX of the illumination optical system. The light is incident on the mirror 6A in the deformable mirror 5 from a direction orthogonal to the mirror. Illumination light IL
Part 2 is reflected downward by the mirror 6A.
The illumination light IL2 that has passed below the mirror 6A is
Mirror 6B in deformed mirror 5 reflected by A and 7B
And the light beam reflected by the mirror 6B is incident on the condenser lens 9 together with the light beam reflected by the mirror 6A. Although not shown, an optical system similar to the optical system including the light source unit 2, the relay lens 4, and the mirrors 7A and 7B is also arranged in a direction perpendicular to the plane of FIG. Illumination light (also referred to as illumination light IL2) that is non-photosensitive to the photoresist from the third light source unit disposed in the vertical direction is lowered by mirrors 6C and 6D (see FIG. 3) in the deformable mirror 5. Is reflected by Therefore, the illumination light IL2
Is reflected by a circular area inside the annular area 15 through which the illumination light IL1 passes in FIG.

In FIG. 1, the illumination light IL1 passing around the deformable mirror 5 and the illumination light IL2 reflected by the deformable mirror 5 are both irradiated onto the reticle 10 by the condenser lens 9. The illumination lights IL1 and IL2 applied to the reticle 10 pass through the pattern area on the reticle, and are applied to the wafer 13 via the projection optical system 12. Under the illumination light IL1 for exposure, the pattern surface of the reticle 10 and the surface of the wafer 13 are conjugate with respect to the projection optical system 12, and the illumination light IL2 is non-photosensitive to the photoresist on the wafer 13. , The illumination light I for the exposure
Only the pattern image on the reticle 10 illuminated by L1 exposes the photoresist on the wafer 13. In this case, the pupil plane PS in the projection optical system 12, that is, the optical Fourier transform plane with respect to the pattern plane of the reticle 10, is
The aperture stop AS is arranged on the pupil plane PS, being conjugate with the arrangement surface of 6C and thus the upper surface of the deformable mirror 5.

The wavelength λ1 of the illumination light IL1 and the wavelength λ2 of the illumination IL2 depend on the type of photoresist and the projection optical system 12.
In general, the wavelength λ1 is less than 530 nm, and the wavelength λ2 is 530.
Select a wavelength of at least nm. As the illumination light IL1 for exposure, i-line of a mercury lamp is used in this example,
In addition, bright lines such as a g-line (wavelength 436 nm) of a mercury lamp, ArF excimer laser light (wavelength 193.2 nm) and KrF excimer laser light (wavelength 248.5 nm), or harmonics of a copper vapor laser or a YAG laser are used. Can be used. The illumination light IL2 has a wavelength at which the photoresist is not exposed, and the amount of light absorbed per unit area by the glass material or the coating film of the lens is the illumination light IL1 as a whole.
Is preferable. In that sense, as the illumination light IL2, when the light absorption rate is low, the light intensity of the light source is high, while when the light intensity of the light source is low, the projection optical system 1
It is preferable that the second lens has as large an optical absorptivity as possible with respect to the glass material or coating film. As an example of the illumination light IL2, for example, a laser beam (wavelength: 633 nm) from a He—Ne laser or the like can be given.

When a glass material such as quartz or a glass having a good transmittance from the ultraviolet region to the near-infrared region is used as a glass material for the lens of the projection optical system, these glass materials have a thickness of about 2 μm.
m has a considerable light absorption from long wavelengths of m or more,
As the illumination light IL2, HF chemical laser light (wavelength: 2.4 to 3.4 μm) using a chemical reaction of hydrogen fluoride (HF) gas
m) and the like may be used. In addition, since optical glasses other than quartz contain impurities, some optical glasses have a light absorptivity close to 1% / cm even at a wavelength of 530 nm or more, and have such a light absorptivity close to 1% / cm. Even illumination light is sufficiently effective. Examples of such illumination light include a C-line (wavelength 656.3 nm) from a hydrogen (H ₂ ) discharge tube and a d-line (wavelength 587.6 nm) from a helium (He) discharge tube.
And the like. In FIG. 1, the optical axis AX of the illumination optical system is shown.
1 coincides with the optical axis of the projection optical system 12, takes the Z axis parallel to the optical axis AX, and sets the X axis parallel to the plane of FIG. 1 on a two-dimensional plane perpendicular to the Z axis. The description will be made taking the Y axis perpendicular to the paper surface.

The reticle 10 is mounted on a reticle stage 11 which can be finely moved in the X, Y and rotation directions. The position of the reticle stage 10 is precisely measured by an external laser interferometer (not shown), and the position of the reticle stage 11 is controlled based on the measurement value of the laser interferometer. On the other hand, the wafer 13 is placed on a wafer stage 14 for positioning the wafer in the X, Y, and Z directions via a wafer holder (not shown), and the position of the wafer stage 14 is precisely determined by an external laser interferometer. The position of the wafer stage 14 is controlled based on the measured value. The center of each shot area of the wafer 13 is projected by the wafer stage 14 onto the projection optical system 1.
The operation of moving to the center of exposure 2 and the exposure operation are repeated in a step-and-repeat manner, so that the reticle 10
The image of the upper pattern is transferred to each shot area on the wafer 13.

Next, the operation of the projection exposure apparatus of this embodiment will be described. In this example, first, as shown in FIG. 1, an annular stop 26C having a large aperture and a deformable mirror 5 are combined to perform substantially annular illumination with the illumination light IL1 for exposure. High resolution is obtained for periodic patterns. Also, as shown in FIG.
On a plane substantially conjugate to the pupil plane PS of the projection optical system 12, the illumination light IL1 photosensitive to the photoresist passes through the annular zone 15 and is not exposed to the photoresist reflected by the reflection surface of the deformable mirror 5. Illumination light IL2 passes through a region inside the region 15. In such an illumination state, the illumination light IL
1 and IL2 through the reticle 10 of FIG.
, The illumination light IL1, IL2 as a whole passes through a circular area centered on the optical axis AX on the pupil plane PS of the projection optical system 12. Accordingly, the lens of the projection optical system 12 near the pupil plane PS absorbs heat energy not only in the peripheral part but also in the central part, and the temperature rises. Therefore, the pupil plane P
In the lens near S, the ratio of the second-order fluctuation component of the thermal deformation or the change in the refractive index is larger than that of the higher-order fluctuation component. Since the spherical aberration fluctuation of the projection optical system 12 is almost proportional to the thermal deformation of the lens near the pupil plane PS and the change in the refractive index, the spherical aberration fluctuation also has a second-order component, and the higher order of the projection optical system 12 Variations in spherical aberration are suppressed.

FIG. 1 shows a deformed mirror 5 for annular illumination.
In this example, a quadrangular pyramid-shaped deformed mirror 5A also serving as a modified illumination aperture stop 26E shown in FIG. 2C is used.
(See FIG. 3B). That is, when performing the deformed illumination, the deformed mirror 5A is set on the optical path of the illumination light IL1 instead of the deformed mirror 5 via the evacuation and exchange device 8 of FIG.

FIG. 3B shows a deformed mirror 5 for deformed illumination.
FIG. 3A is a view as viewed from the reticle 10 side of FIG.
In (b), the four mirrors 19A to 19D constituting the deformable mirror 5A are arranged in close contact with each other so as to form a quadrangular pyramid having a fan shape equal to each other and having a convex surface directed to the reticle 10 having the optical axis AX as a vertex. ing. In addition, mirror 19A ~
In 19D, the surface on the reticle 10 side is a reflection surface, and the outer shape of the mirrors 19A to 19D viewed from the reticle 10 is a single circumference 16A centered on the optical axis AX as a whole. The circumference 16A is substantially equal to the outer circumference 16 of the circular area through which the illumination light IL1 of FIG. 3A passes. Further, a circular transmission portion 18A as viewed from the reticle 10 side is provided at equal angular intervals inside the outer circumference 16A of each mirror 19A to 19D.
-18D are formed, and the transmitting portions 18A-18D are
Is configured to transmit the illumination light IL1 for exposure. The deformed mirror 5A also serves as the aperture stop 26E for the deformed illumination shown in FIG.

That is, when performing the deformed illumination in this embodiment, the deformed mirror 5A is replaced with the deformed mirror 5A instead of the deformed mirror 5 of FIG. 1 via the evacuation and exchange device 8 of FIG. 1 so that the apex of the pyramid coincides with the optical axis AX. And the vertex thereof is arranged toward the reticle 10 side. As a result, the illumination light IL1 is transmitted through the four transmission portions 18.
The reticle 10 shown in FIG. On the other hand, the non-exposure illumination light IL2 is reflected on a region other than the transmission portions 18A to 18D within the circumference 16A of FIG. Since the upper surface of the deformable mirror 5A is conjugate with the pupil plane PS of the projection optical system 12, a circular area centered on the optical axis AX is illuminated on the pupil plane PS of the projection optical system 12 by the illumination lights IL1 and IL2. You. Therefore, a high resolution can be obtained by the modified illumination method, and high-order spherical aberration fluctuation can be suppressed. In addition, the illumination light IL2 for non-exposure does not adversely affect the imaging characteristics. In FIG. 1, when a normal illumination method is used, the deformable mirrors 5 and 5A are illuminated with the illumination light IL via the evacuation and exchange device 8.
The aperture stops 26A and 26B shown in FIG. 2A may be set as the aperture stops after being retracted from the optical path 1.

The photosensitive illumination light IL1 is reflected on the photoresist by the reflecting surfaces of the deformable mirrors 5 and 5A in FIG. 3A or 3B, and the non-photosensitive illumination light IL2 is reflected on the photoresist. A configuration in which a part is shielded from light may be adopted. In the case of such a configuration, in FIG.
In addition, the arrangement of the related optical systems is exchanged, and a circular transmission part is provided in the center part so that the illumination light IL2 is transmitted, for example, instead of the deformable mirror 5 in FIG. What is necessary is just to use the deformation | transformation mirror which has an annular reflection surface which reflects the illumination light IL1 which injects from the direction orthogonal to the light IL2.

Next, a modification of the first embodiment of the present invention will be described with reference to FIG. This variation is
The illumination light for exposure and the non-photosensitive illumination light on the photoresist are combined in advance, and the combined light is again divided into two illumination lights by a wavelength-selective aperture stop provided in front of the reticle 10, and the reticle 10 is configured to be illuminated. 4, the same reference numerals are given to portions corresponding to FIG. 1, and detailed description thereof will be omitted.

FIG. 4 shows a schematic configuration of a projection exposure apparatus according to the present modification. In FIG. 4, a light source unit for emitting illumination light IL1A which is photosensitive to a photoresist, similarly to the light source unit 1 in FIG. 1A and a light source unit 2A that emits illumination light IL2A that is non-photosensitive to a photoresist, like the light source unit 2 in FIG. And the polarization beam splitter 31 is arrange | positioned in the position where those illumination light IL1A and illumination light IL2A cross. It is assumed that the illumination lights IL1A and IL2A of this modification are linearly polarized light of P polarization. The P-polarized illumination light IL2A of wavelength λ2 emitted from the field stop of the light source unit 2A is:
The light is converted into a parallel light beam by the relay lens 4A, passes through the polarization beam splitter 31, and is converted into circularly polarized light by the quarter wavelength plate. On the other hand, the P-polarized illumination light IL1A emitted from the field stop of the light source unit 1A and converted into a parallel light flux by the relay lens 3A passes through the polarization beam splitter 31 from a direction orthogonal to the optical path of the illumination light IL2A, and
After being reflected by the mirror 33 via the four-wavelength plate 32,
The light enters the ４ wavelength plate 32 and is converted into S-polarized light. The illumination light IL1A converted into the S-polarized light is reflected by the polarization beam splitter 31, and enters the quarter-wave plate 34,
Converted to circularly polarized light. The illumination lights IL1A and IL2A converted into circularly polarized light by the 波長 wavelength plate 34 enter the aperture stop 37 having wavelength selectivity via the relay lenses 35 and 36.

FIG. 5A is a plan view of the aperture stop 37. In FIG. 5A, the aperture stop 37 has a wavelength λ1.
Illumination light IL1A having a wavelength of λ2
And an illumination filter IL that transmits the illumination light IL2A having the wavelength λ2 and transmits the illumination light IL2A having the wavelength λ1.
And a circular optical filter 38 that hardly transmits 1. The aperture stop 37 is disposed on a plane conjugate with the pupil plane PS of the projection optical system 12 such that the center coincides with the optical axis AX. Then, the illumination light I from the light source unit 1A
L <b> 1 </ b> A is applied to an area including the annular optical filter 39, and illumination light IL <b> 2 </ b> A from the light source unit 2 </ b> A is applied to an area including the circular optical filter 38.

The two illumination lights IL1A and IL2A synthesized by the polarization beam splitter 31 are transmitted through an aperture stop 37.
After passing through the reticle 1 via the condenser lens 9
Irradiated on zero. The pattern image of the reticle 10 is projected onto the wafer 13 via the projection optical system 12. On the pupil plane PS of the projection optical system 12, the same illumination light IL as in the first example is used.
1A and IL2A pass through a substantially circular area. The optical paths of the following illumination lights IL1A and IL2A are the same as in the first example, and description thereof is omitted.

According to this modification, the same high-order spherical aberration reduction effect as that of the first embodiment can be obtained, and at the same time, the aperture stop 37 having wavelength selectivity defines the passage area of the illumination lights IL1A and IL2A. , The deformable mirror 5 as in the first example
A complicated configuration of using the is unnecessary. Also, the wavelength λ
Since only one light source unit 2A is required, the entire apparatus can be made compact. Further, the two light beams of linearly polarized light synthesized by the polarization beam splitter 31 are converted into circularly polarized light by the 波長 wavelength plate 34, so that when the image is formed on the wafer 13, the direction of the pattern of the reticle 10 changes. However, good transfer is performed. Note that the polarization beam splitter 31
Alternatively, a dichroic mirror 31A can be used as shown by a two-dot chain line in FIG. The dichroic mirror 31A has a wavelength selectivity of transmitting the illumination light IL2A and reflecting the illumination light IL1A, whereby the two illumination lights IL1A and IL2A are combined without waste. In this case, the quarter-wave plates 32 and 34 and the mirror 33 are not required, and the configuration is simplified. Further, the aperture stop 37 shown in FIG.
Is configured so that it can be replaced with an aperture stop 37A for deformed illumination by a device similar to the evacuation and replacement device 8 of FIG.

FIG. 5B is a plan view of an aperture stop 37A having wavelength selectivity that is used in place of the aperture stop 37 of FIG. 4 when performing modified illumination. The aperture 37A transmits four small circular optical filters 40A to 40D that transmit the illumination light IL1A of the wavelength λ1 and hardly transmit the illumination light IL2A of the wavelength λ2, and a wavelength λ2 in a region excluding these optical filters 40A to 40D. Illumination light IL2A having a wavelength of λ1
Optical filter 41 having a circular outer shape that hardly transmits 1A
It is composed of The optical filter 41 is shown in FIG.
(A) has an outer diameter substantially equal to the outer diameter of the optical filter 39, and has four small circular openings formed at equal angular intervals near the outer periphery thereof; Filters 40A to 40D are provided. The illumination light IL1A for exposure includes four optical filters 40A.
The illumination light IL2A that passes through -40D and is not photosensitive to the photoresist passes through an optical filter 41 surrounding the optical filters 40A-40D. As a result, deformed illumination is performed, and high-order spherical aberration fluctuation is suppressed.

In FIGS. 5A and 5B, the optical filters 38 and 40A to 40D through which the illumination light IL1A from the light source section 1A passes are transmitted as much as possible to the illumination light IL2A from the light source section 2A. What does not
The effect of reducing high-order spherical aberration fluctuation is large and desirable. Next, a second embodiment of the projection exposure apparatus according to the present invention will be described with reference to FIG. In this example, the present invention is applied to a case where an annular pupil filter is used. In FIG. 6, parts corresponding to those in FIG. 1 are given the same reference numerals, and detailed description thereof will be omitted.

FIG. 6 shows a schematic configuration of the projection exposure apparatus of the present embodiment. In FIG.
Will be described separately for the upper lens system 12A and the lower lens system 12B. In this example, a quadrangular pyramid-shaped deformed mirror 5B similar to the deformed mirror 5 of FIG. 1 is arranged near the pupil plane PS between the upper lens system 12A and the lower lens system 12B. Illumination light IL1B having a wavelength λ1 that is photosensitive to a photoresist emitted from a field stop of a light source unit 1B similar to the light source unit 1 of FIG. 1 is irradiated onto a reticle 10 via a condenser lens. The aperture stop in the light source unit 1B is shown in FIG.
This is a large circle similar to the aperture stop 26C in FIG. The illumination light IL1B transmitted through the reticle 10 is optically Fourier-transformed by the upper lens system 12A, and passes around the deformable mirror 5B. With this deformed mirror 5B, the illumination light IL1B photosensitive to the photoresist is shielded in a circular area centered on the optical axis AX. That is, the deformable mirror 5B
Is also used as an annular pupil filter. On the other hand, the illumination light IL2B which is non-photosensitive to the photoresist having the wavelength λ2 emitted from the light source unit 2B similar to the light source unit 2 of FIG.
The light is reflected toward the wafer 13 by the first reflection surface B.
In this case, similarly to the first example of FIG. 1, the illumination light IL2B that has passed below the deformed mirror 5B is reflected and the deformed mirror 5B is reflected.
Mirrors 7A and 8A for entering the second reflection surface of B
Is arranged.

Further, in this embodiment, a light source section for supplying illumination light of wavelength λ2 to the third and fourth reflecting surfaces of the deformable mirror 5B is provided in a direction perpendicular to the plane of FIG.
The illumination light IL2B reflected by the deformable mirror 5B is irradiated onto the wafer 13 via the lower lens system 12B. In this example, since the area near the optical axis AX of the illumination light IL1B for exposure is shielded by the deforming mirror 5B disposed on the pupil plane PS of the projection optical system 12, a ring-shaped center light shield is provided for a predetermined pattern. The same high resolution as when a pupil filter of the type is installed is obtained. In addition, since the glass material of the lower lens system 12B is illuminated by the two wavelengths of illumination light IL1B and IL2B with a uniform illuminance distribution, high-order thermal deformation and a change in refractive index are suppressed, and the high-order Is suppressed.

As supplemented in the first example of the embodiment of the present invention, the photosensitive illumination light IL1B is reflected on the photoresist on the reflection surface of the deformable mirror 5B, and the photoresist is reflected on the other portions on the photoresist. A configuration in which the non-photosensitive illumination light IL2B is transmitted may be employed. In such a configuration, in FIG. 6, the arrangement of the light source units 1B and 2B, the reticle 10, the upper lens system 12A, and the related optical system are interchanged, and the illumination light IL2B is transmitted to the center as a deformable mirror. It is sufficient to use a deformed mirror having a ring-shaped reflecting surface for the illumination light IL1B incident on the periphery of the circular opening from a direction orthogonal to the illumination light IL2B.

Next, a modification of the second embodiment of the present invention will be described with reference to FIG. The configuration of the projection exposure apparatus of this modification up to the projection optical system is almost the same as that of the modification of the first example of FIG. 4 (however, the aperture stop 37 is omitted). Parts corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.
7 shows a schematic configuration of the projection exposure apparatus of this embodiment. In FIG. 7, the aperture stop shown in FIG. 5A is located near the pupil plane PS between the upper lens system 12A and the lower lens system 12B of the projection optical system 12. An aperture stop 43 having the same wavelength selectivity as that of the aperture stop 37 is provided. The illumination light IL2A having a wavelength λ2 which is non-photosensitive to the photoresist emitted from the light source unit 2A, and the wavelength λ1 which is photosensitive to the photoresist emitted from the light source unit 1A.
The illumination light IL1A is combined by the polarization beam splitter 31, transmitted through the reticle 10, optically Fourier-transformed by the upper lens system 12A of the projection optical system 12, and incident on the aperture stop 43. As shown in FIG. 5A, the aperture stop 43 has a ring-shaped optical filter that transmits only the illumination light IL1A that is photosensitive to the photoresist, and transmits only the non-photosensitive illumination light IL2A to the photoresist inside the filter. A circular optical filter is formed, and the aperture stop 43 functions as a central light shielding type pupil filter for the illumination light IL1A. The other illumination light IL2A is illumination light IL1.
After A has passed through the shaded circular area, the lower lens system 1
The light enters the wafer 13 via 2B.

In this modification, the pupil plane PS of the projection optical system 12
6, a high resolution can be obtained as in the example of FIG. Further, since the glass material of the lower lens system 12B is illuminated by the two illumination lights IL1A and IL2A with a uniform illuminance distribution, high-order spherical aberration fluctuation is suppressed. The optical filter that transmits the illumination light IL1A from the light source unit 1A includes the illumination light IL from the light source unit 2A.
It is desirable that an optical filter that does not transmit 2A as much as possible has a large effect of reducing higher-order aberrations. As in the example of FIG. 4, a dichroic mirror may be used instead of the polarization beam splitter 31.

Next, a description will be given, based on a calculation example, that the illuminance distribution to the lens of the projection optical system 12 is made uniform and high-order aberration fluctuation is suppressed in the above embodiment. First, the temperature distribution after the rise due to the illumination light irradiation is calculated. By approximating the lens to a cylindrical shape, heat does not flow out from the side of the lens through the surrounding air, and when the edge of the lens comes into contact with metal, heat flows out only from that edge and the absorbed energy density distribution in the lens changes to light. It is assumed that the angle is constant with respect to the angle around the axis AX. Assuming that a variable representing the radial distance of the lens is r, the temperature distribution after the rise is a variable r
Where T (r) is the heat absorption amount and thermal conductivity per unit volume of the lens, and a is the outer radius of the lens. In the cylindrical coordinate system in a thermal equilibrium state, The heat conduction equation can be expressed as the following equation.

[0041]

１ ² T / ∂r ² + (1 / r) ∂T / ∂r + ω
(R) / λ = 0 By solving this heat conduction equation, the following equation is obtained.

[0042]

(Equation 2)

Here, J _n (p _i · r) is a Bessel function of the n-th order (n = 0, 1, 2,...) Of the first kind,
p _i is a sequence satisfying J ₁ (p _i · a) = 0 (i =
1, 2, 3, ...). The coefficient B _i is obtained by the following equation.

[0044]

(Equation 3)

In particular, when the heat absorption amount ω (r) is represented by a step-like function within the radius of the irradiation area (irradiation radius), that is, at a certain j (1 ≦ j ≦ N), the variable r becomes h _j ≦ r ≦ h
In the section that satisfies _{j + 1,} when the heat absorption amount omega (r) takes a constant value omega _j, the following relation is established.

[0046]

(Equation 4)

[0047] Thus, equation (4) coefficient B _i is obtained by substituting the (number 3), the coefficients B _i (Equation 2)
To obtain the temperature distribution T (r) after the rise. Then, the increase after the temperature distribution T (r), r ¹⁰ to determine which order of aberration variation occurs more, the temperature distribution T after rise (r) with a minimum square method as follows
When the power series is expanded up to the term, the following equation is obtained.

[0048]

T (r) = T ₀ + C ₂ · r ² + C ₄ · r ⁴ + C
₆ · r ⁶ + C ₈ · r ⁸ + C ₁₀ · r ^{10 In} this case, the unit of the temperature distribution T (r) after the rise is ° C., and the unit of the variable r is mm. T ₀ is the optical axis AX, that is, the temperature distribution T (0) after the rise at the position where the variable r is 0.

Hereinafter, a calculation example based on actual numerical values will be described. The value (coherence factor) of the ratio of the numerical aperture on the exit side of the illumination optical system to the numerical aperture (NA) on the entrance side of the projection optical system is defined as a σ value, and this σ value is set to 0.75. An outer radius of 4 is obtained by an illumination system having a σ value of 0.75.
In the case where a lens made of 0 mm cylindrical quartz is illuminated and the radius d of the irradiation area on the lens is 30 mm, calculation is performed based on the solutions of the heat conduction equations of (Equation 2) to (Equation 4). . The thermal conductivity of quartz is 0.0138 W / (c
m · ° C.), and the heat absorption rate of the lens to the illumination light sensitive to the photoresist on the wafer is set to 2% / cm.

In the first calculation example, first, for comparison, calculation is performed for a case where the total irradiation energy amount of the illumination light is 1 W and the lens is uniformly irradiated within a range of σ of 0.75. FIG. 8A shows the temperature distribution T (r) after the rise in the first calculation example, where the horizontal axis represents the variable r and the vertical axis represents the temperature distribution T (r) after the rise. As shown by the solid curve 46A, the temperature distribution T (r) after the rise has a maximum value at the origin, that is, the optical axis AX, and shows a mountain-shaped change that is axisymmetric with respect to the optical axis AX. For reference, the irradiation energy density P (r) of the illumination light is indicated by a dotted line 47A. The irradiation energy density P (r) has a constant value P1 when the variable r is between 0 and d (irradiation radius). Further, Table 1 shows coefficients C _{2 to} C ₁₀ when the temperature distribution T ₀ on the optical axis AX and the temperature distribution T (r) are expanded into a power series by (Equation 5).

[0051]

[Table 1]

Next, a second calculation example will be described. This calculation example is an example in which only annular illumination is performed.
This is a calculation example for comparison as in the calculation example of FIG. The σ value is 0.75 at the maximum, and the σ value inside the annular zone is 0.5. The temperature distribution T (r) after the rise is calculated when the lens is uniformly illuminated when the σ value is in the range of 0.5 to 0.75 and the total irradiation energy amount is 1 W.

FIG. 4B shows a temperature distribution T (r) after the rise according to the second calculation example.
As shown by the solid line curve 46B, the temperature distribution T
(R) is a constant rising temperature TB when the variable r is approximately between 0 and e.
Becomes Irradiation energy density P (r) indicated by dotted line 47B
Indicates that the variable r has a constant value P2 between e and d, and the variable r
Is 0 between 0 and e. Similarly to the first calculation example, the coefficients C ₂ to C ₂ when the temperature distribution T ₀ after the rise on the optical axis AX and the temperature distribution T (r) after the rise are expanded into a power series by (Equation 5). Table ₁₀ shows Table ₁₀ .

[0054]

[Table 2]

Next, a third calculation example will be described. This calculation example is, as in the embodiment shown in FIGS. 1, 4, 6 and 7, two types of illumination light that is photosensitive to the photoresist on the wafer 13 and illumination light that is not photosensitive to the photoresist. The temperature distribution T (r) after the rise when the lens is illuminated by two illumination lights is obtained. In this case, when the σ value is in the range of 0.75 to 0.5, the photoresist is uniformly illuminated with the photosensitive illumination light at a total irradiation energy of 1 W, and the σ value is 0.5 to 0. Within the range of 0.0, the irradiation energy density P (r) is reduced to 0.75 by the illumination light having a wavelength insensitive to the photoresist.
It is assumed that the lens is illuminated so that the irradiation energy density becomes ２ of the irradiation energy density in the range of 0.5 to 0.5.

FIG. 4C shows the temperature distribution T (r) after the rise according to the third calculation example.
As shown by the solid line curve 46C, the temperature distribution T
(R) has a maximum value TC at the origin, that is, the optical axis AX, and shows a mountain-shaped change that is axially symmetric with respect to the optical axis AX. The irradiation energy density P (r) has a constant value P2 when the variable r is between e and d, and a constant value P3 when the variable r is between 0 and e, as shown by a dotted line 47C that changes stepwise. (= P2 /
2). Further, a temperature distribution T ₀ on the optical axis AX,
Table 3 shows coefficients C _{2 to} C ₁₀ when the temperature distribution T (r) is expanded into a power series by (Equation 5).

[0057]

[Table 3]

Note that in the first and second calculation examples,
The total irradiation energy amount is 1 W, and in the third calculation example, the irradiation energy amount is 1 W when the σ value is in the range of 0.75 to 0.5. In the third calculation example, the total irradiation energy exceeds 1 W when the irradiation energy in the range of 0.5 to 0.0 is added. In this case, the irradiation energy (sensitivity) of the illumination light sensitive to the photoresist on the wafer 13 in the first to third calculation examples is set to be equal so that the exposure time (throughput) is equal.

Illumination form shown in the first calculation example (uniform illumination)
In comparison with the illumination modes (zonal illumination) shown in the second calculation example, as shown in Tables 1 and 2, the annular illumination is more uniform than the uniform illumination in the optical axis AX. Low rise temperature. Nevertheless, when the power series coefficient C ₄ is compared, for example, the value of the coefficient C _{4 in} the case of uniform illumination is 4.4.
000 × 10 ^-8 , coefficient C _{4 in} the case of annular illumination
Is 2.7328 × 10 ^−7, which is larger for annular illumination. That is, comparing uniform illumination with annular illumination,
Absolute values of the coefficients of the power series other than the coefficient C ₂ is better for all annular illumination is large. Since the thermal deformation and the change in the refractive index are proportional to the temperature distribution T (r) after the rise, the aberration fluctuation is also proportional to the temperature distribution T (r) after the rise. That the coefficient of the high-order power series from the coefficient C ₂ is greater in all annular illumination means towards the annular illumination is large higher order aberrations change.

Here, if the illumination mode in the embodiment shown in FIGS. 1, 4, 6 and 7 is "synthetic illumination", the illumination light is also applied to the vicinity of the optical axis by the synthetic illumination. As shown in the calculation example of FIG. 3, despite the fact that the total irradiation amount is larger than that of the uniform illumination or the annular illumination, as shown in Tables 1 and 2, the value of the coefficient C ₄ (= 1.7624 × 10 ⁻⁷ ) is smaller than the value of the coefficient C ₄ in the annular illumination (= 2.7328 × 10 ⁻⁷ ). Furthermore, comparing the absolute values of the coefficients C ₆ , C ₈ , and C ₁₀ , the combined illumination is smaller than the annular illumination in any of the coefficients. This means that high-order aberration fluctuations are reduced by the combined illumination.

In the third calculation example, the σ value is 0
The irradiation energy density between 0.5 and 0.5 is の of the density distribution when the σ value is between 0.5 and 0.75. Temperature distribution T when irradiation is performed by irradiation energy distribution
(R) is calculated and compared with the case of the annular illumination of FIG. 4 (b).

The energy density P1 shown in FIG.
Between the irradiation energy density P2 of (b), P2 =
The relationship of 1.8 · P1 is established. Accordingly, in the annular illumination as shown in FIG. 8B, when the irradiation is performed at the same irradiation energy density as the annular illumination area even in a range where the σ value is within 0.5, the irradiation energy in FIG. Density is 1.
This is equivalent to a state multiplied by eight. Therefore, all coefficients of the power series are also multiplied by 1.8, so that the coefficients C ₄ , C ₆ , C
_8, C _10, respectively, 7.9200 × 10 ^-8, -1.78
21 × 10 ⁻¹⁰ , 1.4937 × 10 ⁻¹³ , −3.73
It becomes 41 × 10 ^-17 . When the values of these coefficients are compared with the respective coefficients in Table 2, the coefficients C _{4 to} C ₁₀ are higher even though the temperature distribution T ₀ after the rise near the optical axis AX is considerably larger than that in the case of the annular illumination. Are all smaller than in the case of annular illumination. That is, when the σ value is within the range of 0 to 0.75 by the combined illumination, even when the irradiation is performed at the same irradiation energy density P2 as that of the annular illumination, the higher-order aberration fluctuation is smaller than that of the annular illumination. ing.

In the above-described embodiment, the present invention is applied to a stepper type projection exposure apparatus, but the present invention is also applied to a scanning exposure type projection exposure apparatus such as a step-and-scan method. it can. It should be noted that the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the spirit of the present invention.

[0064]

According to the first projection exposure apparatus of the present invention,
In order to use illumination light for exposure from a light source distributed in a region decentered from the optical axis on a plane conjugate with the pupil plane of the projection optical system, for example, the same improvement in resolution as when performing annular illumination or deformed illumination The effect is obtained. In addition, since non-photosensitive illumination light is applied to the area where the illumination light for exposure does not pass when performing annular illumination or deformed illumination, higher-order thermal deformation or refractive index of the lens of the projection optical system is used. There is an advantage that the change is reduced and a higher-order spherical aberration fluctuation of the projection optical system is suppressed.

When the illumination optical system illuminates the mask with exposure illumination light from an annular light source or a plurality of light sources eccentric to the optical axis, a so-called annular illumination or High resolution can be obtained by deformed illumination. Further, the illumination optical system has an optical integrator for equalizing the illuminance distribution of the illumination light for exposure, and
When an auxiliary light introducing member for guiding illumination light from the auxiliary illumination system to the mask is provided between the integrator and the mask,
The mask can be illuminated in a state where the illumination light for exposure and the non-photosensitive illumination light are accurately separated on a plane conjugate with the pupil plane, and there is an advantage that the imaging characteristics are not deteriorated.

Further, according to the second projection exposure apparatus of the present invention, since the image forming light beam passing through the area decentered from the optical axis on the pupil plane of the projection optical system by the optical member having wavelength selectivity is used, There is an advantage that the same resolution can be obtained as when a ring-shaped center light blocking pupil filter is installed. Further, the lens near the pupil plane of the projection optical system is illuminated with a uniform illuminance distribution by two illumination lights, i.e., illumination light for exposure and non-photosensitive illumination light on the photosensitive substrate. There is an advantage that the higher-order fluctuation component of the refractive index is reduced, and the higher-order spherical aberration fluctuation of the projection optical system is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first example of an embodiment of a projection exposure apparatus of the present invention.

FIG. 2 is an enlarged plan view showing various aperture stops provided in the light source unit of FIG.

3A is a view of the deformed mirror 5 of FIG. 1 viewed from the reticle side, and FIG. 3B is a view of another deformed mirror 5A viewed from the reticle side.

FIG. 4 is a schematic configuration diagram showing a modification of the first example of the embodiment of the present invention.

5A is a plan view showing an aperture stop 37 in FIG. 4, FIG.
(B) is a plan view showing another aperture stop 37A.

FIG. 6 is a schematic configuration diagram showing a second example of the embodiment of the projection exposure apparatus of the present invention.

FIG. 7 is a schematic configuration diagram showing a modification of the second example of the embodiment.

FIG. 8 is a diagram for explaining an example of calculating a temperature distribution based on irradiation energy in the embodiment of the present invention.

[Explanation of symbols]

 1, 1A, 1B Light source unit (for exposure) 2, 2A, 2B Light source unit (for non-exposure) 5, 5A, 5B Deformable mirror 6A to 6D, 19A to 19D Mirror 10 Reticle 12 Projection optical system 12A Upper lens system 12B Lower part Lens system PS Pupil plane 13 Wafer 14 Wafer stage 24 Fly eye lens 26A-26C Aperture stop 31 Polarization beam splitter 32,34 Quarter wave plate 37,37A, 43 Aperture stop having wavelength selectivity

Claims (4)

[Claims] 1. A projection optical system for projecting an image of a pattern on a mask onto a photosensitive substrate under illumination light for exposure, and a projection optical system decentered from an optical axis on a plane conjugate with a pupil plane of the projection optical system. An illumination optical system that illuminates the mask using the illumination light for exposure from a light source distributed in a region, and a projection exposure apparatus, wherein the illumination light in a wavelength range that is insensitive to the photosensitive substrate. A projection exposure apparatus, comprising an auxiliary illumination system for irradiating an area on the pupil plane of the projection optical system through which the illumination light for exposure does not pass. 2. The projection exposure apparatus according to claim 1, wherein the illumination optical system includes illumination light for exposure from a ring-shaped light source or a plurality of light sources eccentric to an optical axis. A projection exposure apparatus, wherein the mask is illuminated by: 3. The projection exposure apparatus according to claim 1, wherein the illumination optical system has an optical integrator for uniforming the illuminance distribution of the exposure illumination light, and A projection exposure apparatus, wherein an auxiliary light introducing member for guiding illumination light from the auxiliary illumination system to the mask is provided between the integrator and the mask; 4. When an image of a pattern on a mask is projected onto a photosensitive substrate via a projection optical system under illumination light for exposure, the pattern is decentered from an optical axis on a pupil plane of the projection optical system. In a projection exposure apparatus using an image forming light beam passing through a region, a synthetic illumination optical system that guides the illumination light for exposure and the illumination light that is insensitive to the photosensitive substrate to a pupil plane of the projection optical system; An optical member that is disposed on a pupil plane of the projection optical system and has wavelength selectivity that allows only non-photosensitive illumination light to pass through the photosensitive substrate to the photosensitive substrate in a region other than a region decentered from the optical axis; And a projection exposure apparatus.