JP3049774B2 - Projection exposure apparatus and method, and element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus used for transferring a circuit pattern of a semiconductor integrated device or a pattern of a liquid crystal device.

[0002]

2. Description of the Related Art For forming a circuit pattern of a semiconductor element or the like,
Generally, a process called photolithography technology is required. In this step, a method of transferring a reticle (mask) pattern onto a sample substrate such as a semiconductor wafer is usually adopted. A photosensitive photoresist is applied on the sample substrate, and a circuit pattern is transferred to the photoresist according to an irradiation light image, that is, a pattern shape of a transparent portion of the reticle pattern. In a projection type exposure apparatus (for example, a stepper), an image of a circuit pattern to be transferred drawn on a reticle is projected and formed on a sample substrate (wafer) via a projection optical system.

[0003] In an illumination optical system for illuminating the reticle, an optical integrator such as a fly-eye lens or a fiber is used, so that the intensity distribution of illumination light applied to the reticle is made uniform. If a fly-eye lens is used to optimize the uniformity,
The reticle-side focal plane and the reticle plane (pattern plane) are almost connected by a Fourier transform, and the reticle-side focal plane and the light source-side focal plane are also connected by a Fourier transform. Therefore, the pattern surface of the reticle and the light source-side focal plane of the fly-eye lens (more precisely, the light source-side focal plane of each fly-eye lens) are formed in an imaging relationship (conjugate relationship). For this reason, on the reticle, the illumination light from each element (secondary light source image) of the fly-eye lens is added (superimposed) and averaged, and the illuminance uniformity on the reticle can be improved. It has become.

In a conventional projection exposure apparatus, the distribution of the amount of illumination light flux incident on the optical integrator incidence surface such as the fly-eye lens described above is substantially circular (or rectangular) around the optical axis of the illumination optical system. Was almost uniform. FIG. 13 shows a schematic configuration of a conventional projection type exposure apparatus (stepper) as described above.
The pattern 17 of the reticle 16 is irradiated through the spatial filter 12 and the condenser lens 15. here,
The spatial filter 12 is disposed on the reticle-side focal plane 11b of the fly-eye lens 11, that is, a Fourier transform plane (hereinafter abbreviated as a pupil plane) with respect to the reticle 16, or in the vicinity thereof. And a secondary light source (surface light source) image formed in the pupil plane is limited to a circular shape. Thus, reticle 16
The illumination light passing through the pattern 17 is imaged on the resist layer of the wafer 20 via the projection optical system 18. here,
A solid line representing a light flux represents a principal ray of light emitted from one point. At this time, the ratio between the numerical aperture of the illumination optical system (11, 12, 15) and the reticle-side numerical aperture of the projection optical system 18, the so-called σ value, is determined by the aperture stop (for example, the aperture diameter of the spatial filter 12). The value is generally about 0.3 to 0.6.

[0005] Now, the illumination light L130 is diffracted by the patterned pattern 17 on the reticle 16, from the pattern 17 0-order diffracted light D _0, + 1-order diffracted light D _P, and -1-order diffracted light D _m occurs. The respective diffracted lights (D ₀ , D _m , D _P ) are condensed by the projection optical system 18 and generate interference fringes on a wafer (sample substrate) 20.
This interference fringe is an image of the pattern 17. In this case, 0-order diffracted light D ₀ and ± 1-order diffracted light D _P, the angle theta (reticle side) and D _m is sinθ = λ / P (λ: exposure wavelength, P: pattern pitch) determined by.

By the way, when the pattern pitch becomes finer, sin θ becomes larger, and when sin θ becomes larger than the reticle-side numerical aperture (NA _R ) of the projection optical system 18, the ± 1st-order diffracted lights D _P and D _m pass through the projection optical system 18. It cannot be transmitted.
At this time, only the _zero-order diffracted light D ₀ reaches the wafer 20 and no interference fringes occur. That is, when sin θ> NA _R , the image of the pattern 17 cannot be obtained, and the pattern 1
7 cannot be transferred onto the wafer 20.

From the above, in the conventional projection type exposure apparatus, the pitch P which satisfies sin θ = λ / P ≒ NA _R
Was given by: P ≒ λ / NA _R (1) From this, since the minimum pattern size is half of the pitch P, the minimum pattern size is about 0.5 · λ / NA _R , but in the actual photolithography process, Some degree of depth of focus is required due to curvature, the effects of process steps, etc., or the thickness of the photoresist itself. Therefore, the practical minimum resolution pattern size is expressed as k · λ / NA. here,
k is called a process coefficient and is about 0.6 to 0.8.
Since the ratio between the reticle-side numerical aperture NA _R and the wafer-side numerical aperture NA _W is the same as the imaging magnification of the projection optical system, the minimum resolution pattern size on the reticle is k · λ / NA _R ,
The minimum pattern size on the wafer is k · λ / NA _W = k
· Λ / B · NA _R (where B is the imaging magnification (reduction ratio)) becomes.

Therefore, in order to transfer a finer pattern, it was necessary to select whether to use an exposure light source having a shorter wavelength or to use a projection optical system having a larger numerical aperture. Of course, efforts can be made to optimize both the exposure wavelength and the numerical aperture. Also, a so-called phase shift reticle that shifts the phase of light transmitted from a specific portion of the transmission portion of the circuit pattern of the reticle by π from the phase of light transmitted from another transmission portion, for example, is disclosed in
50811. Use of this phase shift reticle enables transfer of a finer pattern than in the past.

[0009]

However, in the conventional projection type exposure apparatus as described above, shortening the wavelength of the illumination light source (for example, 200 nm or less) compared with the present one requires an appropriate optical element usable as a transmission optical member. It is difficult at present because of the absence of materials. Also, the numerical aperture of the projection optical system is already close to the theoretical limit at present, and it is almost impossible to increase the numerical aperture further.

Further, even if the aperture can be made larger than the current state, the depth of focus represented by ± λ / 2NA ² rapidly decreases with an increase in the numerical aperture, and the depth of focus required for actual use is reduced. However, the problem that the number is further reduced becomes prominent. On the other hand, the phase shift reticle has many problems such as a high manufacturing cost due to the complicated manufacturing process, and a method of inspection and repair has not been established yet.

The present invention has been made in view of the above problems, and has as its object to realize a projection type exposure apparatus capable of obtaining a high resolution and a large depth of focus even when a normal reticle is used.

[0012]

A projection exposure apparatus according to the present invention uses illumination light (IL) from a light source (1) as a mask (1).
6) an illumination optical system for irradiating the substrate, and a projection optical system (18) for projecting the illumination light onto the substrate (20). The pattern of the mask (17) is transferred onto the substrate by irradiating the illumination light. is there. In the first projection exposure apparatus, the light amount distribution of the illumination light on the Fourier transform plane (a plane conjugate with the pupil plane 19 of the projection optical system) with respect to the pattern (17) of the mask (reticle 16) in the illumination optical system One of a plurality of optical integrators selected according to a pattern to be transferred onto a substrate has one end face (focal plane) corresponding to a Fourier transform plane. It was decided to be arranged almost in agreement. For this reason, the optimal optical integrator can be used according to the pattern to be transferred onto the substrate, and especially when the light intensity distribution of the illumination light is increased in a region outside the optical axis of the illumination optical system, the optimal optical integrator is used. A pattern can be transferred onto a substrate with high resolution and a large depth of focus. In the second projection exposure apparatus,
A plurality of optical integrators (22A to 22A) that form illumination light and form different secondary light sources, respectively.
D, 23A), one of a plurality of optical integrators selected according to the pattern to be transferred onto the substrate has one end face (focal plane) having a Fourier transform plane (pupil of the projection optical system) in the illumination optical system. (A plane conjugate to the plane 19). Therefore, an optimal optical integrator can be used in accordance with a pattern to be transferred onto a substrate, and particularly when a secondary light source is formed off the optical axis of the illumination optical system, a high resolution and high resolution can be obtained by using the optimal optical integrator. The pattern can be transferred onto the substrate with a large depth of focus. In the first and second projection exposure apparatuses, a plurality of optical integrators are arranged on the optical axis (AX) in the illumination optical system, and the first optical integrator (23A) is arranged in the illumination optical system. It is desirable to include second optical integrators (11A, 11B) arranged outside the optical axis (AX). here,
The first and second projection exposure apparatuses according to the present invention use, as an optical integrator, a fly-eye lens in which one end face, that is, a reticle-side focal plane is arranged almost coincident with a Fourier transform plane in an illumination optical system, and Assuming that the light amount distribution of the illumination light on the Fourier transform surface is increased in a region off the optical axis of the illumination optical system, in other words, a secondary light source is formed off the optical axis of the illumination optical system. It is configured as shown in FIG. In FIG. 12, the same members as those in the related art are denoted by the same reference numerals. In FIG. 12, the fly-eye lens (1
1A, 11B) is a position where the reticle-side focal plane 11b is substantially a Fourier transform plane with respect to a circuit pattern (reticle pattern) 17 on the reticle 16 in the illumination optical system (a position conjugate with the pupil plane 19 of the projection lens 18) ), And the fly-eye lenses (11A, 11B) are dispersedly arranged in a plurality of fly-eye lens groups. Also,
In order to make the illumination light amount distribution on the reticle-side focal plane 11b of the fly-eye lenses (11A, 11B) substantially zero at positions other than the individual fly-eye lens positions of the plurality of fly-eye lens groups 11A, 11B,
A, 11B) on the light source side (or on the reticle side, or integrated with the fly-eye lens). Therefore, the illumination light amount distribution on the reticle-side focal plane 11b of the fly-eye lenses (11A, 11B) exists only at the positions of the fly-eye lens groups 11A, 11B, and becomes almost zero at other positions.

Further, fly-eye lens groups 11A and 11B
Since the reticle-side focal plane 11b is substantially equal to the Fourier transform plane for the reticle pattern 17, the light quantity distribution (position coordinates of the luminous flux) on the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B is Of the incident angle の. Accordingly, the incident angle of the illumination light beam incident on the reticle pattern 17 is changed according to the individual positions of the fly-eye lens groups 11A and 11B (positions in a plane perpendicular to the optical axis AX, that is, distances from the optical axis AX). Can be adjusted. Here, the fly-eye lens groups 11A and 11B are desirably arranged symmetrically with respect to the optical axis AX, and each fly-eye lens group is composed of at least one or more lens elements. Furthermore, the eccentric states of the fly-eye lens groups 11A and 11B with respect to the optical axis of the illumination optical system or the projection optical system are made different from each other and integrally held according to the difference in the periodicity (pitch, arrangement direction, etc.) of the reticle pattern 17. Each of the plurality of holding members may be interchangeably arranged in the optical path of the illumination optical system. For this reason, each of the plurality of holding members is arranged in the optical path of the illumination optical system. Specifically, based on the periodicity of the reticle pattern to be transferred, one of the plurality of holding members that is optimal for the reticle pattern is selected. Is selected, and the selected holding member is arranged in the optical path, so that the reticle 1
6 can be controlled in accordance with the periodicity of the reticle pattern 17.

In the third projection exposure apparatus according to the present invention, the light amount distribution of the illumination light (IL) on the Fourier transform plane in the illumination optical system is determined by the periodicity of the pattern (17), that is, the fineness (pitch P). (For example, fly-eye lens 11) decentered from the optical axis (AX) of the illumination optical system by a distance corresponding to
A and 11B are used to increase the light amount distribution according to the pattern to be transferred onto the substrate (20).
A second optical member (72) arranged in the illumination optical system in exchange for the optical member (71), wherein the first and second optical members are optical integrators (30A,
30B; 31A, 31B) are arranged closer to the light source (1). In addition, the first optical member is an optical element (for example, a fiber or a diffraction grating pattern) that distributes the illumination light to the plurality of regions without blocking the illumination light.
It is desirable that Therefore, when using the first optical member, the pattern can be transferred onto the substrate with high resolution and a large depth of focus. Further, by using the second optical member in exchange for the first optical member, it is possible to reduce a light amount loss that may be caused, for example, by changing the light amount distribution. In the above-described first to third projection exposure apparatuses, a driving unit that relatively moves the substrate and the image plane of the projection optical system in a direction along the optical axis during exposure of the substrate with the illumination light is provided. The apparent depth of focus may be increased. Also,
In the fourth projection exposure apparatus according to the present invention, the light amount distribution of the illumination light on the Fourier transform surface in the illumination optical system is increased in a plurality of regions decentered from the optical axis (AX) of the illumination optical system, and the pattern (17) is increased. ), An optical member (11) for defining the distance from the optical axis (AX) to be substantially equal in a plurality of regions in accordance with the periodicity of fineness (pitch P); Driving means (110, 112) for relatively moving the image plane of the projection optical system in a direction along the optical axis are provided. Therefore, the pattern can be transferred onto the substrate with a high resolution and a large depth of focus, and the apparent depth of focus can be further increased. Further, in the element manufacturing method using the projection exposure apparatus according to the present invention, a fine semiconductor element or the like can be manufactured by a photolithography process for forming a circuit pattern. Further, in the projection exposure method according to the present invention, the illumination light (IL) from the light source (1) is masked (1) through the illumination optical system.
6), and the substrate (20) is exposed to illumination light via the projection optical system (18). And
In the first projection exposure method, a plurality of optical integrators (11A11B; 22A to 22C) that vary the light intensity distribution of illumination light on a Fourier transform plane in an illumination optical system according to a pattern to be transferred onto a substrate (20). 22D; 23A)
Is selected, and the selected optical integrator is arranged in the illumination optical system such that one end face thereof substantially coincides with the Fourier transform plane. For this reason, the optimal optical integrator can be used according to the pattern to be transferred onto the substrate, and especially when the light intensity distribution of the illumination light is increased in a region outside the optical axis of the illumination optical system, the optimal optical integrator is used. A pattern can be transferred onto a substrate with high resolution and a large depth of focus. In the second projection exposure method, the light amount distribution of the illumination light on the Fourier transform surface in the illumination optical system is determined by using the optical axis (A
X), the distance from the optical axis (AX) is set to be substantially equal in the plurality of regions in accordance with the periodicity of the pattern to be transferred onto the substrate, that is, the fineness (pitch P). During the exposure of the substrate by the illumination light, the substrate and the image plane of the projection optical system are relatively moved in a direction along the optical axis. Therefore, the pattern can be transferred onto the substrate with a high resolution and a large depth of focus, and the apparent depth of focus can be further increased.

[0015]

The circuit pattern 17 drawn on the reticle (mask) generally contains many periodic patterns.
Thus, from a single fly's eye lens groups 11A reticle pattern 17 the illumination light is irradiated from the 0-order diffracted light component D ₀ and ± 1-order diffracted light component D _P, is D _m and higher diffracted light components, It occurs in a direction corresponding to the fineness of the pattern. At this time, since the illumination light beam (principal ray) is incident on the reticle 16 at an inclined angle, the generated diffracted light components of each order also have a certain inclination (angle shift) as compared with the case where the illumination is performed vertically. From 17 Illumination light L120 in FIG. 12 is incident on reticle 16 at an angle of ψ with respect to the optical axis.

The illumination light L120 is diffracted by the reticle pattern 17, the optical axis 0-order diffracted light proceeds only direction inclined ψ relative AX D _0, 0 +1 order diffracted light D _P advancing inclined by theta _P relative order diffracted light , And θ with respect to the _0th- order diffracted light D _0
A -1st-order diffracted light Dm that advances by _m is generated. Since the illumination light L120 is incident on the reticle pattern inclined at an angle ψ with respect to the optical axis AX of the double telecentric projection optical system 18, 0-order diffracted light D ₀ also with respect to the optical axis AX of the projection optical system Proceed in the direction inclined by angle ψ.

Accordingly, the + 1st-order diffracted light D _P travels in the direction of (θ _P + ψ) with respect to the optical axis AX, and the −1st-order diffracted light D _m in the direction of (θ _m −ψ) with respect to the optical axis AX. proceed. At this time, the diffraction angles θ _P and θ _m are respectively sin (θ _P + ψ) −sinψ = λ / P (2) sin (θ _m −ψ) + sinψ = λ / P (3) Here, the + 1st-order diffracted light _Dp and the -1st-order diffracted light D
It is assumed that both _m are transmitted through the pupil 19 of the projection optical system 18.

When the diffraction angle increases with the miniaturization of the reticle pattern 17, firstly, the + 1st-order diffracted light D _P traveling in the direction of the angle (θ _P + ψ) cannot pass through the pupil 19 of the projection optical system 18. That is, sin (θ _P + ψ)> NA _R
It comes to the relationship. However, the illumination light L120 has the optical axis A
Since the incident inclined relative X, -1-order diffracted light D _m at a diffraction angle in this case is possible enter the projection optical system 18. That is, a relationship of sin (θ _m −ψ) <NA _R is established.

Therefore, the zero-order diffracted light D ₀ is placed on the wafer 20.
When -1 interference fringes caused by two light beams of the diffracted light D _m occurs.
This interference fringe is an image of the reticle pattern 17. When the reticle pattern 17 has a line and space ratio of 1: 1, the image of the reticle pattern 17 is formed on a resist layer applied on the wafer 20 with a contrast of about 90%. Can be patterned.

The resolution limit at this time is when sin (θ _m -ψ) = NA _R (4), and therefore, NA _R + sinψ = λ / PP = λ / (NA _R + sinψ) (5) ) Is the pitch of the smallest transferable pattern on the reticle side.

As an example, if sinψ is determined to be about 0.5 × NA _R , the minimum pitch of the pattern on the transferable reticle is P = λ / (NA _R + 0.5NA _R ) = 2λ / 3NA _R ( 6)

On the other hand, as shown in FIG. 13, in the case of a conventional projection exposure apparatus in which the light amount distribution of the illumination light on the pupil 19 is within a circular area centered on the optical axis AX of the projection optical system 18,
The resolution limit was P ≒ λ / NA _R as shown in equation (1). Therefore, it can be seen that higher resolution can be realized than the conventional projection type exposure apparatus. Next, by exposing the reticle pattern to exposure light at a specific incident angle, a method of forming an imaging pattern on the wafer using the 0th-order diffracted light component and the 1st-order diffracted light component increases the depth of focus. The reason will be described.

As shown in FIG. 12, when the wafer 20 coincides with the focal position (the best image forming plane) of the projection optical system 18, one point on the reticle pattern 17 exits and becomes one point on the wafer 20. Each of the diffracted light components that arrive has an equal optical path length regardless of which part of the projection optical system 18 passes. For this reason, even when the 0th-order diffracted light component passes through substantially the center (near the optical axis) of the pupil plane 19 of the projection optical system 18, the optical path length between the 0th-order diffracted light component and the other diffracted light components differs. Equal, mutual wavefront aberration is also zero. However, when the wafer 20 is in a defocused state where the focal position of the projection optical system 18 is not coincident, the optical path length of the obliquely incident high-order diffracted light component is focused on the 0th-order diffracted light component passing near the optical axis. It is short in front (away from the projection optical system 18),
Behind the focal point (the one approaching the projection optical system 18), it becomes longer,
The difference depends on the difference between the incident angles. Therefore, 0
The diffracted light components of the next order, ± 1st order,... Mutually form wavefront aberrations, causing blur before and after the focal position.

The wavefront aberration due to the above-mentioned defocus is represented by ΔF, the amount of deviation from the focal position of the wafer 20, and the sine of the incident angle θ _w when each diffracted light component is incident on the negative side.
When (r = sinθ _w), it is an amount given by ΔFr ^2/2. At this time, r represents the distance of each diffracted light component from the optical axis AX on the pupil plane 19. In the conventional projection exposure apparatus shown in FIG. 13 (stepper), 0-order diffracted light D ₀ becomes r (0-order) = 0 because passing near the optical axis AX. On the other hand, ± first-order diffracted lights D _P and D _m are r (first order) = M · λ /
P (M is the imaging magnification of the projection optical system).

Therefore, the 0th-order diffracted light D ₀ and the ± 1st-order diffracted light D
_P, the wavefront aberration due to defocus of the D _m is, ΔF · M
^{2 (λ} / P) becomes a ^2/2. On the other hand, in the projection type exposure apparatus in the present invention, since 0-order diffracted light component D ₀ as shown in FIG. 12 is generated by a direction inclined an angle ψ from the optical axis AX, the optical axis of the 0-order diffracted light component on the pupil plane 19 The distance from AX is r (0th order) = M · sinψ.

Furthermore, the distance from the optical axis in the -1 pupil plane of the diffracted light component D _m is r (-1 order) = M · sin (θ _m
−ψ). At this time, sinψ = sin (θ
if the _{m -ψ),} 0 relative wavefront aberration becomes zero due to defocusing of the order diffracted light component D ₀ and -1-order diffracted light component D _m, even wafer 20 is slightly deviated in the optical axis direction from the focal position pattern The image blur of No. 17 does not occur so much as in the conventional case. That is, the depth of focus increases. Also, as in equation (3), sin (θ _m −ψ) + sinψ
= Λ / P, the incident angle ψ of the illumination light beam L120 to the reticle 16 is given by s with respect to the pattern of the pitch P.
If the relationship inψ = λ / 2P is determined, it is possible to greatly increase the depth of focus.

[0027]

FIG. 1 shows the configuration of a projection type exposure apparatus according to a first embodiment of the present invention.
The diffraction grating pattern 5 is provided as an optical member (part of the input optical system) for concentrating the light amount distribution of the illumination light on each light source side focal plane 11a of B.

In FIG. 1, an illumination light flux IL generated by a mercury lamp 1 is condensed at a second focal point f ₀ of an elliptical mirror 2 and then passed through a relay system such as a mirror 3 and a lens system 4 to form a diffraction grating pattern. 5 is irradiated. The lighting method at this time is
Either the Koehler illumination method or the critical illumination method may be used, but the critical illumination method is more preferable for obtaining a strong light amount. Diffracted light I generated from diffraction grating pattern 5
La and ILb are intensively incident on each of the fly-eye lens groups 11A and 11B by the relay lens 9. At this time, the focal plane 11a on the light source side of the fly-eye lens groups 11A and 11B and the diffraction grating pattern 5 have a substantially Fourier transform relationship via the relay lens 9. On the other hand, the reticle-side focal plane 1 of the fly-eye lens groups 11A and 11B
1 b is arranged in an in-plane direction perpendicular to the optical axis AX so as to substantially coincide with the Fourier transform plane (pupil conjugate plane) of the reticle pattern 17. In FIG. 1, the illumination light to the diffraction grating pattern 5 is illustrated as a parallel light flux. However, since the light is actually a divergent light flux, the fly-eye lens group 11A,
The light beam incident on 11B has a certain size (thickness).

The center of each of the fly-eye lens groups 11A and 11B (in other words, the center of gravity of each light quantity distribution formed by the secondary light source images in each of the fly-eye lens groups 11A and 11B) is a reticle pattern. The fly-eye lens groups 11A and 11A are set at discrete positions eccentric with respect to the optical axis AX by an amount determined according to the periodicity.
B are held together. Further, the movable member 24 (switching member of the present invention) and the holding member 11 are held with the eccentric states of the plurality of fly-eye lens groups different from each other with respect to the optical axis AX according to the difference in the periodicity of the reticle pattern 17. A plurality of holding members (not shown) are integrally fixed. By driving the movable member 24, each of the plurality of holding members can be exchangeably arranged in the optical path of the illumination optical system. However, the details will be described later.

Here, it is desirable that each of the plurality of fly-eye lens groups (11A, 11B) fixed to the same holding member has the same shape and the same material (refractive index). Furthermore, each lens element of each of the fly-eye lens groups 11A and 11B shown in FIG. 1 is a biconvex lens, and the light source side focal plane 11a and the reticle side focal plane 11b coincide with the exit plane respectively. Although described as an example, the lens elements of the fly-eye lens group do not have to strictly satisfy this relationship, and the lens elements may be plano-convex lenses, convex-planar lenses, or plano-concave lenses.

The light source side focal plane 1 of the fly-eye lens group
1a and the reticle-side focal plane 11b naturally have a Fourier transform relationship. Therefore, in the case of the example of FIG.
The reticle-side focal plane 11b of the fly-eye lens group, that is, the exit planes of the fly-eye lens groups 11A and 11B have an imaging relationship (conjugate) with the diffraction grating pattern 5. The luminous flux emitted from the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B illuminates the reticle 16 with uniform illumination distribution via the condenser lenses 13 and 15 and the mirror 14. In this embodiment, the light shielding member 12 is arranged on the emission side of the fly-eye lens groups 11A and 11B,
The zero-order diffracted light ILc and the like from the diffraction grating pattern 5 are cut. The light-shielding member 12 is formed by patterning an opaque substance such as a metal on a metal plate or a glass or quartz substrate whose opening is cut out in accordance with the fly-eye lens group. The openings of the light blocking member 12 correspond to the positions of the fly-eye lens groups 11A and 11B, respectively. For this reason, the illumination light amount distribution in the vicinity of the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B can be made zero except for the positions of the respective fly-eye lens groups 11A and 11B. Therefore, the illuminating light applied to the reticle pattern 17 is only the light flux (light flux from the secondary light source image) emitted from the fly-eye lens groups 11A and 11B, and the incident angle on the reticle pattern 17 is also a specific incident angle. Is restricted to only a plurality of light fluxes having.

In this embodiment, since the holding members (fly-eye lens groups 11A and 11B) are replaceable, the opening of the light shielding member 12 can be changed accordingly, or the light shielding member can be changed. 12 must also be interchangeable. For example, it is desirable that the light shielding member 12 is fixed to the holding member together with the fly-eye lens groups 11A and 11B, and these are integrally replaceable. The size (thickness) of the light beam incident on each of the fly-eye lens groups 11A and 11B is determined by the size of the fly-eye lens groups 11A and 11B.
Needless to say, it is not necessary to provide the light shielding member 12 in the illumination optical system (near the fly-eye lens group) if the size is substantially equal to or smaller than the size of the light source side focal plane 11a.

As described above, by irradiating the reticle pattern 17 with the illumination light at a specific incident angle, the diffracted light generated from the reticle pattern 17 on the reticle 16 becomes
As in the case described with reference to FIG. 12, the light is condensed and imaged by the telecentric projection optical system 18, and the image of the reticle pattern 17 is transferred onto the wafer 20. When the illumination light flux is diffracted using the above-described diffraction grating pattern 5 and the diffracted light is concentrated at a specific position (fly-eye lens group) within the light source-side focal plane of the fly-eye lens groups 11A and 11B, the concentration is concentrated. The position changes depending on the pitch and directionality of the diffraction grating pattern 5. Therefore, each fly-eye lens 11
The pitch and directionality of the diffraction grating pattern 5 are determined so as to concentrate the illumination light at the positions A and 11B.

As described above, an image of the diffraction grating pattern 5 is formed on the reticle-side focal plane 11b of the fly-eye lens 11, and the reticle-side focal plane of the reticle pattern plane 17 and the fly-eye lens groups 11A and 11B. Surface 11b
Is a Fourier transform relationship, so that the illumination intensity distribution on the reticle 16 is not made non-uniform due to defects in the diffraction grating pattern 5 or dust. Further, the diffraction grating pattern 5 itself does not form an image on the reticle 16 to deteriorate the illuminance uniformity.

Here, the diffraction grating pattern 5 may be formed by patterning a light-shielding film such as Cr on the surface of a transparent substrate, for example, a glass substrate, or by patterning a dielectric film such as SiO _2. A so-called phase grating may be used. In the case of a phase grating, the generation of zero-order diffracted light can be suppressed. Further, the diffraction grating pattern 5 may be not only a transmissive pattern but also a reflective pattern. For example, a high reflectivity film on a surface of a plane reflecting mirror such as glass, that is, a metal film such as Al or a dielectric multilayer film patterned in a diffraction grating shape may be used.
Further, a high reflectance mirror in which a step for giving a phase difference to the reflected light is patterned in a diffraction grating shape may be used.

When the diffraction grating pattern 5 is reflective, as shown in FIG. 2, the reflective diffraction grating pattern 5A is irradiated with an illumination light beam from the relay lens system 4, and reflected and diffracted there. The diffracted light may be concentrated near the fly-eye lens groups 11A and 11B via the relay lens 9. Incidentally, even when the individual fly-eye lens groups 11A and 11B move (that is, the holding members are replaced), the diffraction grating pattern is formed so that the illumination light can be concentrated near the respective fly-eye lens groups 11A and 11B. 5 or 5A
Can be exchanged for one with a different pitch.

The diffraction grating pattern 5 or 5A may be rotatable in any direction in a plane perpendicular to the optical axis AX. In this case, when the pitch direction of the line and space pattern in the reticle pattern 17 is different from the X and Y directions (that is, the fly-eye lens groups 11A and 11B move (rotate around the optical axis AX) according to the pitch direction). ).

Further, the relay lens 9 may be a zoom lens system (such as an afocal zoom expander) composed of a plurality of lenses, and the focal position may be changed by changing the focal length. However, in this case, the diffraction grating pattern 5 or 5A and the fly-eye lens groups 11A and 11B
And the light source side focal plane 11a are almost in a Fourier transform relationship.

FIG. 1 shows a main control system 50 for controlling the entire apparatus, and a bar code indicating a name formed beside the reticle pattern 17 while the reticle 16 is being conveyed immediately above the projection optical system 18. A bar code reader 52 for reading BC, a keyboard 54 for inputting commands and data from an operator, and a movable member to which a plurality of holding members (fly-eye lens groups 11A and 11B and a light shielding member 12) are fixed are driven. A drive system (motor, Gatoren, etc.) 56 is provided. In the main control system 50,
The names of a plurality of reticles to be handled by this projection type exposure apparatus (for example, a stepper) and the operation parameters of the stepper corresponding to each name are registered in advance. When the barcode reader 52 reads the reticle barcode BC, the main control system 50 determines the positions of the fly-eye lens groups 11A and 11B registered in advance (pupil conjugate plane) as one of the operation parameters corresponding to the name. One of the holding members that best matches the information (corresponding to the periodicity of the reticle pattern) is output from the plurality of holding members, and a predetermined drive command is output to the drive system 56. . As a result, the holding member (the fly-eye lens groups 11A and 11B) selected previously is set at the position described with reference to FIG. The above operation can also be executed by the operator directly inputting commands and data from the keyboard 54 to the main control system 50.

The first embodiment has been described above.
The optical member for concentrating the light quantity distribution on the light source side focal plane of the fly-eye lens group near the position of each fly-eye lens is not limited to the diffraction grating pattern 5 or 5A alone. Instead of the reflective diffraction grating pattern 5A shown in FIG. 2, the movable plane mirror 6 is arranged as shown in FIG. 3, and a driving member 6a such as a motor for rotating the movable plane mirror 6 is provided. If the plane mirror 6 is rotated or vibrated by the driving member 6a, the light quantity distribution in the light source side focal plane (incident plane) 11a of the fly-eye lens groups 11A and 11B can be changed with time. If the plane mirror 6 is rotated to a plurality of appropriate angular positions during the exposure operation, the light amount distribution in the light source side focal plane 11a of the fly-eye lens groups 11A and 11B is changed to one of the plurality of fly-eye lens groups. It can be concentrated only near the position of one fly-eye lens group. When such a movable reflecting mirror 6 is used, the relay lens system 9 may be omitted.

Further, each fly-eye lens group 11
When A and 11B move (replace the holding member 11), the angle coordinates of the plurality of angular positions of the plane mirror 6 are changed, and the reflected light flux is concentrated near the fly-eye lens group at the new position. good. Incidentally, the light blocking member 12 shown in FIG. 3 is provided on the incident surface side of the fly-eye lens groups 11A and 11B, but may be provided on the exit surface side as in FIG.

FIG. 4 shows an optical fiber bundle 7 as an optical member for condensing an illumination light beam in each of the fly-eye lens groups.
It is a schematic diagram when using. It is assumed that the light source side of the relay lens system 4 and the reticle side of the fly-eye lens groups 11A and 11B have the same configuration as in FIG. Emitted from the light source,
The illumination light transmitted through the relay lens system 4 is incident on the incident portion 7a of the optical fiber bundle 7 after being adjusted to a predetermined numerical aperture (NA). The optical fiber bundle 7 is divided into a plurality of bundles corresponding to the number of fly-eye lens groups before reaching the emission unit 7b.
Each of the emission sections 7b includes a fly-eye lens group 11A,
11B is arranged near the light source side focal plane 11a. At this time, a lens (for example, a field lens) may be provided between each of the emission portions 7b of the optical fiber bundle 7 and the fly-eye lens group 11, and the light source side focal plane of the fly-eye lens group 11 may be provided by the lens. The relationship between the light emission surface 11a and the light emission surface of the optical fiber emission portion 7b may be a Fourier transform. Furthermore, if each emission unit 7b (or a lens between the emission unit 7b and the fly-eye lens group 11b) can be moved one-dimensionally or two-dimensionally in a plane perpendicular to the optical axis by a driving member such as a motor. Also, even when the fly-eye lens group moves with the replacement of the holding member, the illumination light beam can be concentrated near the position of each of the moved fly-eye lens groups.

FIG. 5 shows an example in which a prism 8 having a plurality of refracting surfaces is used as an optical member for concentrating an illumination light beam on each fly-eye lens group. The prism 8 in FIG.
It is divided into two refraction surfaces with X as a boundary, and the optical axis A
The illumination light incident above X is refracted upward, and the optical axis AX
Illumination light incident below is refracted downward. Therefore, on the light source side focal plane 11a of the fly-eye lens groups 11A and 11B, the illumination light can be concentrated near the individual fly-eye lens groups 11A and 11B according to the refraction angle of the prism 8.

The number of divisions of the refracting surface of the prism 8 is not limited to two, but may be any number according to the number of fly-eye lens groups. Further, the division position may not be limited to a position symmetric with respect to the optical axis AX. Further, by exchanging the prism 8, even when the fly-eye lens groups 11A and 11B move with the exchange of the holding member, the illuminating luminous flux is appropriately concentrated on the positions of the respective fly-eye lens groups 11A and 11B. be able to.

The prism 8 at this time may be a polarizing light splitter such as a Wollaston prism. However, in this case, since the polarization directions of the divided light beams are different from each other, the polarization characteristics of the resist on the wafer 20 are taken into consideration.
It is better to arrange the polarization characteristics in one direction. If a reflecting mirror having a plurality of reflecting surfaces having different angles is arranged as shown in FIG. 3 instead of the prism 8, the driving member 6a becomes unnecessary. Needless to say, it is preferable that the apparatus has an exchange function of the prism and the like. Also, when such a prism or the like is used, the relay lens system 9 can be omitted.

FIG. 6 shows a plurality of mirrors 8a and 8b as optical members for concentrating an illumination light beam on each fly-eye lens group.
This is an example using 8c and 8d. In FIG. 6, illumination light transmitted through the relay lens system 4 is reflected by the primary mirrors 8b and 8c so as to be separated in two directions, guided to the secondary mirrors 8a and 8d, reflected again, and fly-eye. The light reaches the light source side focal plane 11a of the lens groups 11A and 11B. If each of the mirrors 8a, 8b, 8c, 8d is provided with a position adjustment mechanism and a rotation angle adjustment mechanism around the optical axis AX, the fly-eye lens groups 11A, 11B accompanying the replacement of the holding member are provided.
After the movement, the illumination light beam can be concentrated near each of the fly-eye lens groups 11A and 11B. Further, each of the mirrors 8a, 8b, 8c, 8d may be a plane mirror or a convex or concave mirror.

A lens may be provided between each of the secondary mirrors 8a and 8d and each of the fly-eye lens groups 11A and 11B. In FIG. 6, the primary mirrors 8b and 8c and the secondary mirror 8 are shown.
Both a and 8d are two, but the number is not limited to this, and mirrors may be appropriately arranged according to the number of fly-eye lens groups. In each of the above embodiments,
Although all the fly-eye lens groups are two, the number of fly-eye lens groups may of course be three or more. In addition, as for the optical members for concentrating the illumination light on the individual fly-eye lens groups, the light concentration was mainly described in two places, but the illumination light was concentrated on a plurality of positions according to the number of fly-eye lens groups. Needless to say, In the above-described embodiments, the illumination light can be concentrated at any position (corresponding to the position of the fly-eye lens group). The optical member for concentrating the illumination light on each fly-eye lens group is not limited to the type described in the embodiment, but may be any other type.

The light shielding member 12 may be replaced with a light shielding member 10 provided near the light source side focal plane 11a of the fly-eye lens group as shown in FIG. 12 described above, or shown in FIGS. Each of the embodiments described above may be used in combination with the light shielding member 10 shown in FIG. Also, the light shielding member 1
Reference numerals 0 and 12 denote focal planes 11 on the reticle side of the fly-eye lens group.
b and the light source side focal plane 11a, it can be arranged at any position.
1b is a suitable place.

The individual fly-eye lens groups 11A,
An optical member (input optical system) for concentrating the illumination light only in the vicinity of 11B is for preventing a loss of the amount of illumination light for illuminating the reticle 16, and has a high resolution characteristic of the projection type exposure apparatus of the present invention. And it is not directly related to the configuration for obtaining the effect of the large depth of focus. Therefore, the optical member may be a lens system having a large diameter enough to cause the illumination light to enter the flood in each of the plurality of fly-eye lens groups.

FIG. 7 is a view showing a configuration of a projection type exposure apparatus (stepper) according to another embodiment of the present invention. A mirror 14, a condenser lens 15, a reticle 16, and a projection optical system 18 are the same as those in FIG. is there. Here, the holding member 11 for holding the fly-eye lens groups 11A and 11B and the movable member 24 are omitted. The light source side of the fly-eye lens groups 11A and 11B has one of the configurations shown in FIGS. 1 to 6 or FIG. further,
Near the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B, a light-shielding member 12a having an arbitrary opening (transmission part) is provided.
The illumination light beam emitted from 1B is restricted.

Since the Fourier transform of the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B with respect to the relay lens 13a is a conjugate plane with the reticle pattern 17,
Here, a variable field stop (reticle blind) 13d is provided. Then, the Fourier transform is again performed by the relay lens 13b, and reaches the conjugate plane (Fourier plane) 12b of the reticle-side focal plane 11b of the fly-eye lens groups 11A and 11B. The light shielding member 12a may be provided on the Fourier surface 12b.

The luminous flux from each of the fly-eye lens groups 11A and 11B is further supplied to condenser lenses 13C and 13C.
5 and the mirror 14 guide the reticle 16.
It should be noted that if the illumination light flux entering each of the fly-eye lens groups 11A and 11B can be effectively concentrated only there, there is no problem even if the light shielding member is not provided at the position 12a or 12b in the drawing. Even in such a case, it is possible to use the field stop (reticle blind) 13d.

In any of the above embodiments, the diameter per opening of the light-blocking members 10, 12, and 12a (or the area of each exit end of the fly-eye lens group) is determined by the luminous flux transmitted through the opening. Ratio of the numerical aperture of the projection optical system 18 to the reticle 16 on the reticle side (NA _R ),
It is desirable to set so-called σ value to be about 0.1 to 0.3. If the σ value is smaller than 0.1, the pattern fidelity of the transferred image is degraded. Further, in order to satisfy the condition of the σ value (about 0.1 < σ < 0.3) determined by one of the fly-eye lens groups, the size of the exit end area of each of the fly-eye lens groups 11A and 11B (light (The size in the in-plane direction perpendicular to the axis) may be determined according to the illumination light flux (emission light flux).

Each fly-eye lens group 11A, 11
A variable aperture stop (equivalent to the light shielding member 12) may be provided near the reticle-side focal plane 11b of B, and the numerical aperture of the light beam from each fly-eye lens group may be changed to change the σ value. At the same time, a variable aperture stop (N) is positioned near a pupil (entrance pupil or exit pupil) 19 in the projection optical system 18.
A limit aperture) can be provided to further optimize the NA and the σ value of the projection system.

The luminous flux incident on each fly-eye lens group is widely illuminated to some extent outside the incident end face of each fly-eye lens group, and the distribution of the amount of light incident on each fly-eye lens group is uniform. This is preferable because the illuminance uniformity on the reticle pattern surface can be further improved.
Next, the structure of the movable member 24 (switching member of the present invention) suitable for holding member replacement suitable for each of the above embodiments will be described with reference to FIGS.

FIG. 8 is a view showing a specific configuration of the movable member. In this case, four holding members 11, 21, 22, 2,
3 are arranged on a movable member (turret plate) 24 rotatable about a rotation shaft 24a at intervals of about 90 °. FIG. 8 shows a state in which the illumination light beams ILa and ILb (dotted lines) are incident on the fly-eye lens groups 11A and 11B, respectively, and the holding member 11 is arranged in the illumination optical system. At this time, the holding member 11 is positioned between the center thereof and the optical axis AX.
Are arranged in the illumination optical system such that the values substantially coincide with each other. The plurality of fly-eye lens groups 11A and 11B are integrated such that their centers are set at discrete positions eccentric to the optical axis AX of the illumination optical system by an amount determined according to the periodicity of the reticle pattern. Is held by the holding member 11,
Here, they are arranged substantially symmetrically with respect to the center (optical axis AX) of the holding member 11.

Now, the four holding members 11, 21, 22,
Each of the plurality of fly-eye lens groups 23 has an eccentric state (that is, a position in a plane substantially perpendicular to the optical axis AX) with respect to the optical axis AX (the center of the holding member) according to the difference in the periodicity of the reticle pattern 17. ) Are kept different from each other. Each of the holding members 11 and 21 has two fly-eye lens groups (11A and 11B) and (21A and 21B). When these fly-eye lens groups are arranged in the illumination optical system, their arrangement directions Are fixed so as to be substantially orthogonal to each other. The holding member 22 arranges and fixes the four fly-eye lens groups 22A to 22D at substantially the same distance from the center 22c (optical axis AX). The holding member 23 has one fly-eye lens group 23A fixed substantially at the center, and is used when performing conventional exposure.

As is apparent from FIG. 8, the turret plate 24 is rotated by the drive element 25 including a motor and gears in accordance with the information of the reticle bar code BC as described above, so that the four holding members 11, 21, and 22 are held. ,
23 can be exchanged, and a desired holding member corresponding to the periodicity (pitch, arrangement direction, etc.) of the reticle pattern can be arranged in the illumination optical system.

Here, since a plurality of fly-eye lens groups are fixed in a predetermined positional relationship in each of the four holding members, it is not necessary to perform position adjustment between the plurality of fly-eye lens groups when replacing the holding members. Absent. Accordingly, since the entire holding member may be aligned with the optical axis AX of the illumination optical system, there is an advantage that a precise positioning mechanism is not required. At this time, since the drive element 25 is also used for positioning, it is desirable to provide a rotation angle measuring member such as a rotary encoder. As shown in FIG. 8, each of the plurality of fly-eye lens groups constituting the holding member has 16 fly-eye lens groups (only fly-eye lens group 23A has 3 fly-eye lens groups).
6), but is not limited to this, and in extreme cases, may be a fly-eye lens group composed of one lens element.

In FIG. 1, the light shielding member 12 is disposed behind the holding member 11 (on the reticle side). However, if each of the holding members is a light shielding part other than the fly-eye lens group, the light shielding member 12 is particularly provided. No need to provide. At this time,
The turret plate 24 may be a transmission part or a light shielding part.
Further, the number of holding members to be fixed to the turret plate 24,
The eccentric states (positions) of the plurality of fly-eye lens groups are not limited to those shown in FIG. 8, but may be set arbitrarily according to the periodicity of the reticle pattern to be transferred. When it is necessary to strictly set the angle of incidence of the illumination light beam on the reticle pattern, each of the plurality of fly-eye lens groups in the holding member is moved in the radial direction (radiation direction) around the optical axis AX. And a holding member (fly-eye lens group 1) about the optical axis AX.
1A, 11B) may be configured to be rotatable. On this occasion,
Particularly, when the optical fiber bundle 7 (FIG. 4) is used as an optical member (input optical system) for concentrating the illumination light flux near each of the plurality of fly-eye lens groups, the movement of the fly-eye lens group is accompanied by the movement. The emission end 7b may also be configured to move, for example, the emission end 7b and the fly-eye lens group may be fixed integrally. In addition, the rectangular fly-eye lens group also relatively tilts with the rotation of the holding member, but when the holding member is rotated, the above-described tilt does not occur, and only the position of the fly-eye lens group moves. It is desirable to configure.

When the holding member is replaced, the input optical system, for example, the diffraction grating pattern 5, the relay lens 9 (FIG. 1), the optical fiber bundle 7 (FIG. 4), and the like also need to be replaced. It is preferable that an input optical system corresponding to the eccentric state of the plurality of fly-eye lens groups is integrally formed for each member and fixed to the movable member 24.

FIG. 9 is a view showing a modification of the movable member for replacing the holding member. The input optical system (optical fiber bundles 71 and 72) and the holding member (32 and 34) are integrally formed with the movable member (support rod). 36). Here, the case where an optical fiber bundle is used will be described, but the input optical system may be another optical system shown in FIGS. Note that the basic configuration (an example in which an optical fiber bundle is used as an input optical system) has been described with reference to FIG. 4 and will be briefly described here.

In FIG. 9, the two fly-eye lens groups 30A and 30B are integrally held by a holding member 32,
The optical fiber bundle 71 has an incident portion 71a and an emission portion 71b.
Are held together by the fixture 33, and the holding member 32 is integrally fixed to the fixture 33. The inside of the holding member 32 includes fly-eye lens groups 30A and 30B.
Except for the light shielding portion (corresponding to the shaded portion in the figure, for example, the light shielding member 12 in FIG. 1). On the other hand, the replacement fly-eye lens groups 31A and 31B are integrally held by a holding member 34, and the optical fiber bundle 72 has its incident part 72a and its emitting part 72b both held by the fixture 35, and the holding member 34 It is integrally fixed to the fixture 35, and the inside is a light shielding portion as described above. Further, the fixing members 33 and 35 are connected and fixed by a connecting member 37. Therefore, when the holding member is replaced, it is sufficient to replace the entire fixture. In FIG. 9, the fixture 33 (holding member 32) exists in the illumination optical system, and the fixture 3 for replacement is used.
Reference numeral 5 is set at a position outside the illumination optical system. It is assumed that the light source side of the relay lens system 4 and the reticle side of the condenser lens 13 have the same configuration as in FIG. 1, for example.

Incidentally, the replacement of the holding member is performed by the drive element 3.
8 by pushing and pulling the support bar 36. Therefore, if the fly-eye lens group and the optical fiber bundle can be integrally replaced when the holding member is replaced as shown in FIG. 9, the integrated member group (fixing tool) and the entire illumination optical system can be positioned. There is an advantage that it is only necessary to perform alignment, and it is not necessary to adjust the position between each member (fly-eye lens group, optical fiber bundle, etc.) for each exchange. At this time,
Since the drive element 38 is also used for positioning, it is desirable to provide a position measuring member such as a linear encoder or a potentiometer.

The number of fly-eye lens groups and the number of lens elements forming the fly-eye lens group for each holding member shown in FIGS. 8 and 9 may be arbitrary, and the fly-eye lens group and the entrance surface of the lens element are optional. Alternatively, the shape of the emission surface is not limited to a rectangle. Now, each position (position in a plane perpendicular to the optical axis) of the plurality of fly-eye lens groups shown in FIGS. 8 and 9, in other words, the holding member to be selected depends on the reticle pattern to be transferred. It is good to decide (change). The decision (selection) method in this case is, as described in the operation section, an optimum resolution for the fineness (pitch) of the pattern to which the illuminating light beam from each fly-eye lens group is to be transferred, and an effect of improving the depth of focus. A holding member having a fly-eye lens group at a position (incident angle ψ) incident on the reticle pattern or in the vicinity thereof may be used so as to obtain the above.

Next, a specific example of determining the position of each fly-eye lens group for selecting an optimal holding member will be described with reference to FIGS. 10 and 11A to 11D. FIG. 10 shows reticle pattern 1 from fly-eye lens groups 11A and 11B.
7 is a diagram schematically illustrating a portion up to 7, wherein a reticle-side focal plane 11 b of the fly-eye lens group 11 coincides with a Fourier transform plane 12 c of the reticle pattern 17. At this time, a lens or a lens group that makes them have a Fourier transform relationship is represented as a single lens 15. Further, the reticle-side focal plane 11 of the fly-eye lens group 11 is shifted from the fly-eye lens-side principal point of the lens 15.
The distance to b and the distance from the reticle-side principal point of the lens 15 to the reticle pattern 17 are both assumed to be f.

FIGS. 11A and 11C are diagrams each showing an example of a partial pattern formed in the reticle pattern 17, and FIG. 11B is a view showing the case of the reticle pattern shown in FIG. Indicates the position of the center of the optimum fly-eye lens group on the Fourier transform plane (or the pupil plane of the projection optical system),
FIG. 11D is a diagram showing an optimal position of each fly-eye lens group in the case of the reticle pattern of FIG. 11C.

FIG. 11A shows a so-called one-dimensional line-and-space pattern in which a transparent portion and a light-shielding portion are arranged in a band in the Y direction with the same width, and they are arranged at a pitch P in the X direction.
Are arranged regularly. At this time, the optimum positions of the individual fly-eye lens groups are on the line segment Lα in the Y direction assumed in the Fourier transform plane and the line segment L as shown in FIG.
Any position on β. FIG. 11B is a diagram of the Fourier transform surface 12c (11b) with respect to the reticle pattern 17 as viewed from the optical axis AX direction. 11 (A). Now, in FIG. 11B, the distances α and β from the center C through which the optical axis AX passes to the line segments Lα and Lβ are α = β, and when λ is the exposure wavelength, α = β = f · ( 1/2) ２ (λ / P). If these distances α and β can be expressed as f · sinψ, sinψ =
λ / 2P, which is in agreement with the numerical value described in the operation section. Therefore, if the respective center positions of the fly-eye lenses are on the line segments Lα and Lβ, 0 is generated by the illumination light from each fly-eye lens group with respect to the line and space pattern as shown in FIG. The two diffracted lights, one of the first-order diffracted light and the ± first-order diffracted light, pass through the projection optical system pupil plane 19 at a position that is substantially equidistant from the optical axis AX. Therefore, as described above, the depth of focus for the line and space pattern (FIG. 11A) can be maximized, and high resolution can be obtained.

FIG. 11C shows a case where the reticle pattern is a so-called isolated space pattern.
Further, the pitch in the X direction (horizontal direction) of the pattern is Px, and the pitch in the Y direction (vertical direction) is Py. FIG. 11 (D)
FIG. 11 is a diagram showing the optimum position of each fly-eye lens group in this case, and the position and rotation relationship with FIG.
This is the same as the relationship between (A) and (B). When illumination light is incident on a two-dimensional pattern as shown in FIG. 11C, two-dimensional patterns corresponding to the periodicity (X: Px, Y: Py) in the two-dimensional direction are obtained.
Diffracted light is generated in the dimensional direction. Also in the two-dimensional pattern as shown in FIG. 11C, one of the 0th-order diffracted light and ± 1st-order diffracted light in the diffracted light is substantially equidistant from the optical axis AX on the pupil plane 19 of the projection optical system. In this case, the depth of focus can be maximized. In the pattern of FIG. 11C, the pitch in the X direction is Px.
As shown in (D), α = β = f · (1/2) · (λ / P
If the center of each fly-eye lens group is on the line segments Lα and Lβ as x), the depth of focus can be maximized for the X-direction component of the pattern. Similarly, γ = ε = f · (1
If the center of each fly's eye lens group is on the line segments Lγ and Lε that satisfy (/ 2) · (λ / Py), the depth of focus can be maximized for the pattern Y component.

[0070] above, the illumination light from the fly-eye lens group disposed in each location shown in FIG. 11 (B) or (D) is incident on the reticle patterns 17, and 0-order diffraction light component D _0, + 1-order DOO either one of the diffracted light component D _R or -1-order diffracted light component D _m is the pupil plane 19 of the projection optical system 18
Passes through an optical path that is approximately equidistant from the optical axis AX. Therefore, as described in the operation section, a projection type exposure apparatus with high resolution and large depth of focus can be realized.

The reticle pattern 17 shown in FIG.
Although only the two examples shown in (A) or (C) were considered, even for other patterns, attention was paid to the periodicity (fineness), and a + 1st-order or -1st-order diffracted light component from that pattern was used. And two luminous fluxes of the 0th-order diffracted light component,
In the pupil plane 19 in the projection optical system, the center of each fly-eye lens group may be arranged at a position that passes through an optical path that is almost equidistant from the optical axis AX. Also, in the pattern examples of FIGS. 11A and 11C, since the ratio (duty ratio) between the line portion and the space portion is 1: 1, ± 1st-order diffracted light is strong in the generated diffracted light. For this reason, attention was paid to the positional relationship between one of the ± 1st-order diffracted lights and the 0th-order diffracted light. However, when the pattern differs from a duty ratio of 1: 1 or the like, another diffracted light, for example, one of the ± 2nd-order diffracted lights The positional relationship between the zero-order diffracted light and the zero-order diffracted light may be substantially equidistant from the optical axis AX on the pupil plane 19 of the projection optical system.

The reticle pattern 17 is shown in FIG.
When a two-dimensional periodic pattern is included as shown in (D),
When focusing on one specific zero-order diffracted light component, on the pupil plane 19 of the projection optical system, the first-order or higher-order diffracted light components distributed in the X direction (first direction) around the one zero-order diffracted light component. And first-order or higher-order diffracted light components distributed in the Y direction (second direction). So, one particular 0
Assuming that a two-dimensional pattern is favorably formed on the second-order diffracted light component, one of the higher-order diffracted light components distributed in the first direction and one of the higher-order diffracted light components distributed in the second direction are identified. The position of a specific zero-order diffracted light component (one fly-eye lens group) may be adjusted such that the three zero-order diffracted light components are distributed on the pupil plane 19 at substantially the same distance from the optical axis AX. For example, the center position of each fly-eye lens group in FIG. Each of the points Pζ, Pη, Pκ, and Pμ is a line segment Lα or Lβ (the position optimal for the periodicity in the X direction, that is, the 0th-order diffracted light and one of the ± 1st-order diffracted lights in the X direction are on the pupil plane 19 of the projection optical system). , And the intersection of the line segments Lγ and Lε (the optimal position for the periodicity in the Y direction), so that the optimal light source is used in both the X direction and the Y direction. Position.

In the above description, a pattern having a two-dimensional direction is assumed at the same location on the reticle as a two-dimensional pattern. The above method can be applied also to the above. When the pattern on the reticle has a plurality of directions or finenesses, the optimal position of the fly-eye lens group corresponds to each directionality and fineness of the pattern as described above, or The fly-eye lens group may be arranged at the average position of the optimum positions. In addition, the average position may be a load average in which a weight according to the fineness and importance of the pattern is added.

An example of determining the positions of a plurality of fly-eye lens groups has been described above. However, the illumination light beam is generated by the above-described optical member (diffraction grating pattern, movable mirror, prism, fiber, or the like) when the holding member is replaced. Although the concentration is made corresponding to the movement position of each fly-eye lens group, an optical member for such concentration may not be provided. Further, the light beams emitted from the fly-eye lens groups enter the reticle at an angle. At this time, if the direction of the center of gravity of the light quantity of these inclined incident light beams (plurality) is not perpendicular to the reticle, a problem occurs that the position of the transferred image shifts in the in-plane direction of the wafer 20 when the wafer 20 is slightly defocused. I do. In order to prevent this, the direction of the center of gravity of the light quantity of the illumination light beam (plural) from each fly-eye lens group is set to be perpendicular to the reticle pattern, that is, parallel to the optical axis AX. That is, when an optical axis (center line) is assumed for each fly-eye lens group, a position vector of the optical axis (center line) on the Fourier transform plane with respect to the optical axis AX of the projection optical system 18 and What is necessary is just to make the vector sum of the product with the light quantity emitted from the fly-eye lens group zero.

As a simpler method, the number of fly-eye lens groups is 2 m (m is a natural number), and m
Are determined by the aforementioned optimization method (FIG. 12),
The remaining m pieces may be arranged at positions symmetrical to the m pieces with respect to the optical axis AX. Further, when the apparatus has, for example, n (n is a natural number) fly-eye lens groups, and the number of required fly-eye lens groups is m less than n, the number remains (nm). The fly-eye lens group need not be used. In order to eliminate the use of the (nm) fly-eye lens groups, the light shielding member 10 or 12 may be provided at the position of the (nm) fly-eye lens groups. At this time, it is preferable that the optical member that concentrates the illumination light at the position of each fly-eye lens group does not concentrate on the (nm) fly-eye lenses.

It is desirable that the position of the opening of the light-shielding member 10 or 12 is variable in accordance with the movement of each fly-eye lens group accompanying the replacement of the holding member. Alternatively, a mechanism for replacing the light shielding members 10 and 12 according to the position of each fly-eye lens may be provided, and some types of light shielding members may be provided in the apparatus. In each of the above embodiments, it is assumed that a plurality of holding members (fly-eye lens groups) are configured to be replaceable. However, in the present invention, it is not particularly necessary to configure the holding member to be replaceable. Needless to say, for example, even if only the holding member 11 shown in FIG. 8 is simply arranged in the illumination optical system, the effect of the present invention (implementation of a projection type exposure apparatus having a high resolution and a large depth of focus) is of course realized. )
Can be obtained. In addition, when there is no problem even if there is some loss of the illumination light amount from the light source, an optical member (input optical system) for concentrating the illumination light flux particularly on the fly-eye lens group.
There is no need to place.

In the above embodiments, the mercury lamp 1 is used as the light source. However, other bright line lamps, lasers (such as excimer lasers), or light sources having a continuous spectrum may be used. Although most of the optical members in the illumination optical system are lenses, mirrors (concave mirrors, convex mirrors) may be used. The projection optical system may be a refraction system, a reflection system, or a catadioptric system. In the above embodiment, a double-sided telecentric projection optical system is used, but a one-sided telecentric system or a non-telecentric system may be used. Further, in order to use only light of a specific wavelength among the illumination light generated from the light source, a monochromatic unit such as an interference filter may be provided in the illumination optical system.

The fly-eye lens groups 11A and 11B
The illumination light may be made uniform by using a light scattering member such as a diffusion plate or a bundle of optical fibers near the light source side focal plane 11a. Alternatively, apart from the fly-eye lens group used in the embodiment of the present invention, the illumination light may be made uniform using an optical integrator such as a fly-eye lens (hereinafter, another fly-eye lens). At this time, another fly-eye lens is an optical member that makes the illumination light amount distribution variable near the light source side focal plane 11a of the fly-eye lens groups 11A and 11B, for example, the diffraction grating pattern 5 shown in FIGS. Alternatively, it is desirable to be closer to the light source (lamp) 1 than to 5A. Furthermore, the cross-sectional shape of the lens element of another fly-eye lens is square (rectangular)
It is more preferable that the shape be a polygon, especially a regular hexagon.

FIG. 14 shows a configuration around a wafer stage of a projection type exposure apparatus applied to each embodiment of the present invention. And its reflected beam 100
An oblique incidence type autofocus sensor for receiving B light is provided. This focus sensor detects a shift in the optical axis AX direction between the surface of the wafer 20 and the best image forming plane of the projection optical system 18.
The servo control of the motor 112 of the Z stage 110 on which 0 is placed. As a result, the Z stage 110 moves slightly in the vertical direction (optical axis direction) with respect to the XY stage 114, and exposure is always performed in the best focus state. In an exposure apparatus capable of performing such focus control, the apparent depth of focus can be further increased by moving the Z stage 110 in the optical axis direction at a controlled speed characteristic during the exposure operation. This method uses the projection optical system 18.
If the image side (wafer side) is telecentric, any type of projection type exposure apparatus (stepper) can be realized.

FIG. 15 (A) shows a light amount (dose) distribution or existence probability in the optical axis direction obtained in the resist layer with the movement of the Z stage 110 during exposure, and FIG. 15 (B).
Is a Z stage 1 for obtaining a distribution as shown in FIG.
10 shows speed characteristics. 15A and 15B, the vertical axis represents the wafer position in the Z (optical axis) direction, the horizontal axis in FIG. 15A represents the existence probability, and the horizontal axis in FIG. 110 represents the speed V. Also, in the figure, the position Z ₀ is the best focus position.

Here, the projection optical system 1 is moved up and down from the position Z _0.
8 theoretical focal depth ± [Delta] D ₀ f apart two positions + Z _1, and approximately equal maxima existence probability in -Z _1, small values of the presence probability is a range of positions + Z ₃ ~-Z ₃ therebetween I tried to hold it. Therefore, Z stage 11
0 is the position at the start of opening the shutter inside the illumination system -Z
_2, to move up and down in a constant speed at a low speed V _1, immediately after the shutter is fully opened, to accelerate to a higher velocity V _2. While Z stage 110 at a velocity V ₂ is vertically moved in a constant speed, the existence probability is being pushed to a lower value, the Z stage 110 when it reaches the position + Z ₃ starts deceleration toward the low speed V ₁ , the existence probability becomes maximum at the position + Z _1. At this time, a shutter closing command is output almost simultaneously, and the position +
Shutter Z ₂ is completely closed.

As described above, the light amount distribution (existence probability) in the optical axis direction of the exposure amount given to the resist layer of the wafer 20 is separated by the depth of focus width (2 · ΔD ₀ f).
When the speed of the Z stage 110 is controlled so as to have a local maximum value, the contrast of the pattern formed on the resist layer slightly decreases, but a uniform resolving power can be obtained over a wide range in the optical axis direction.

The above progressive focus exposure method can be used in exactly the same manner in a projection exposure apparatus employing a special illumination method as shown in each embodiment of the present invention, and the apparent depth of focus is as follows. The enlargement is performed by an amount substantially corresponding to the product of the enlargement obtained by the illumination method of the present invention and the enlargement obtained by the cumulative focus exposure method. In addition, since a special illumination system is adopted, the resolution itself becomes high.
For example, the minimum line width that can be exposed by combining a conventional 1/5 reduction i-line stepper (NA 0.42 of a projection lens) with a phase shift reticle is about 0.3 to 0.35 μm, and the magnification of the depth of focus is The maximum is about 40%. On the other hand, when a special illumination system such as the present invention was incorporated into the same i-line stepper and an experiment was conducted using a normal reticle,
The minimum line width was about 0.25 to 0.3 μm, and the enlargement ratio of the depth of focus was about the same as when the phase shift reticle was used.

[0084]

As described above, according to the present invention, it is possible to realize a projection type exposure apparatus having a higher resolution and a larger depth of focus than the conventional one while using a normal mask. In addition, according to the present invention, it is only necessary to change the illumination system part of the projection type exposure apparatus already operating at the semiconductor production site, and to use the projection optical system of the operating apparatus as it is to increase the resolution higher than before. Becomes possible.

Further, according to the method of concentrating the illumination light on the fly-eye lens group described in each embodiment of the present invention, the loss of the illumination light amount from the light source can be minimized. There is also an effect that the throughput is not extremely reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a projection exposure apparatus according to a first embodiment of the present invention.

FIG. 2 shows a first example of centralizing illumination light to a fly-eye lens group.
It is a figure which shows the modification of.

FIG. 3 shows a second method of concentrating illumination light on a fly-eye lens group.
It is a figure which shows the modification of.

FIG. 4 is a diagram illustrating a third example of centralizing the illumination light to the fly-eye lens group.
It is a figure which shows the modification of.

FIG. 5 is a diagram illustrating a fourth example of centralizing the illumination light to the fly-eye lens group.
It is a figure which shows the modification of.

FIG. 6 shows a fifth example of centralizing the illumination light to the fly-eye lens group.
It is a figure which shows the modification of.

FIG. 7 is a diagram showing an illumination system when a reticle blind is incorporated in the apparatus of FIG. 1;

FIG. 8 is a diagram showing a specific configuration of a movable member (switching member of the present invention) for exchanging four holding members composed of a plurality of fly-eye lens groups.

FIG. 9 is a view showing a modified example of a movable member that exchanges a plurality of holding members.

FIG. 10 is a diagram schematically illustrating an optical path from a fly-eye lens group to a projection optical system.

FIGS. 11A and 11C are plan views showing an example of a reticle pattern formed on a mask. (B),
(D) is a diagram for explaining the arrangement of each fly-eye lens group on the pupil conjugate plane corresponding to each of (A) and (C).

FIG. 12 is a diagram illustrating the principle of the present invention.

FIG. 13 is a diagram showing a configuration of a conventional projection exposure apparatus.

FIG. 14 is a diagram showing a configuration around a wafer stage of the projection type exposure apparatus.

FIG. 15 shows the existence probability of an exposure amount when executing a progressive focus exposure method using a Z stage among wafer stages;
5 is a graph showing a speed characteristic of a Z stage.

[Explanation of symbols]

 Reference Signs List 5 diffraction grating pattern 9 relay lens system 11A, 11B fly-eye lens system 10, 12 light shielding member (spatial filter) 15 condenser lens 16 reticle 17 reticle pattern 18 projection optical system 19 pupil 20 wafer 24, 36 movable member

Claims (30)

(57) [Claims] An illumination optical system for irradiating illumination light from a light source onto a mask, and a projection optical system for projecting the illumination light onto a substrate, wherein the illumination light irradiates the pattern of the mask onto the substrate. A plurality of optical integrators for differentiating the light amount distribution of the illumination light on the Fourier transform plane for the pattern in the illumination optical system, according to a pattern to be transferred onto the substrate. The projection exposure apparatus according to claim 1, wherein one of the plurality of selected optical integrators is arranged such that one end surface thereof substantially coincides with the Fourier transform plane. 2. An illumination optical system for irradiating illumination light from a light source to a mask, and a projection optical system for projecting the illumination light onto a substrate, wherein the illumination light irradiates the pattern of the mask onto the substrate. A plurality of optical integrators, each of which receives the illumination light and forms a different secondary light source, and wherein the plurality of optical integrators are selected according to a pattern to be transferred onto the substrate. The projection exposure apparatus is characterized in that one end surface of the projection exposure apparatus is arranged so as to substantially coincide with a Fourier transform plane for the pattern in the illumination optical system. 3. The plurality of optical integrators,
The optical system according to claim 1, further comprising: a first optical integrator disposed on the optical axis in the illumination optical system, and a second optical integrator disposed off the optical axis in the illumination optical system. 3. The projection exposure apparatus according to 2. 4. The two diffracted lights having different orders generated from the pattern due to irradiation of light emitted from the second optical integrator, have substantially the same distance from the optical axis on a pupil plane of the projection optical system. 4. The projection exposure apparatus according to claim 3, wherein the position of the second optical integrator is determined so as to pass through the position. 5. An incident angle of the light emitted from the second optical integrator to the mask, を, a diffraction angle of two diffracted lights of the same order generated from the pattern, θ, a mask side of the projection optical system. Assuming that the numerical aperture is NA _R ,
5. The projection exposure apparatus according to claim 3, wherein the position of the second optical integrator is determined such that a relationship of sin (θ−ψ) = NA _R is satisfied for one of the two diffracted lights. 6. The projection exposure apparatus according to claim 5, wherein the one diffracted light is substantially symmetric with respect to an optical axis of the projection optical system and a zero-order diffracted light generated from the pattern. 7. The wavelength of the illumination light is λ, the pitch of the pattern is P, and the incident angle ψ of the light emitted from the second optical integrator to the mask is sinψ = λ.
The projection exposure apparatus according to any one of claims 3 to 6, wherein the position of the second optical integrator is determined so as to satisfy a relationship of / 2P. 8. The zero-order diffracted light and the zero-order diffracted light generated from the pattern by irradiation of light emitted from the second optical integrator when the pattern is provided along first and second directions intersecting each other. One of the higher-order diffracted lights distributed in the first direction with respect to the first direction, and one of the higher-order diffracted lights distributed in the second direction with the zero-order diffracted light as the center, on the pupil plane of the projection optical system. The projection exposure apparatus according to any one of claims 3 to 7, wherein the position of the second optical integrator is determined so as to be distributed substantially equidistant from an axis. 9. When the patterns are provided along first and second directions intersecting each other, the patterns intersect at the optical axis on the Fourier transform plane and are defined along the first and second directions. The projection exposure apparatus according to any one of claims 3 to 8, wherein the second optical integrator is disposed in an area delimited by the first and second axes. 10. A ratio between a numerical aperture of light emitted from the second optical integrator and a numerical aperture on a mask side of the projection optical system is set to about 0.1 to 0.3. The projection exposure apparatus according to any one of claims 3 to 9. 11. The optical integrator of claim 2, wherein:
4. The illumination optical system according to claim 3, wherein said plurality of illumination optical systems are arranged at a plurality of positions substantially equal to an optical axis thereof.
The projection exposure apparatus according to any one of claims 10 to 10. 12. The optical system according to claim 1, wherein each of the plurality of optical integrators is a fly-eye lens whose emission-side focal plane is arranged substantially coincident with the Fourier transform plane. The projection exposure apparatus according to claim 1. 13. An illumination optical system further comprising an optical integrator provided apart from the optical integrator arranged in the illumination optical system in the direction of the optical axis in the illumination optical system. The projection exposure apparatus according to any one of the above. 14. An optical system according to claim 1, further comprising an input optical system for illuminating the illumination light from said light source without blocking the incident light, and for irradiating the incident light on the incident surface of an optical integrator arranged in the illumination optical system. 14. The projection exposure apparatus according to any one of claims 13 to 13. 15. The projection exposure apparatus according to claim 14, wherein the input optical system includes a diffractive optical element that receives the illumination light and generates diffracted light. 16. An illumination optical system for irradiating illumination light from a light source onto a mask, and a projection optical system for projecting the illumination light onto a substrate, wherein the illumination light irradiates the pattern of the mask onto the substrate. In the projection exposure apparatus, the light amount distribution of the illumination light on the Fourier transform surface for the pattern in the illumination optical system is decentered from the optical axis of the illumination optical system by a distance corresponding to the fineness of the pattern. A first optical member used to increase the light intensity distribution in the plurality of regions, and changing the light amount distribution in accordance with a pattern to be transferred onto the substrate, by replacing the first optical member with the first optical member. And a second optical member disposed in the illumination optical system, wherein the first and second optical members are disposed closer to the light source than an optical integrator in the illumination optical system. . 17. The projection exposure apparatus according to claim 16, wherein the first optical member distributes the illumination light to each of the plurality of areas without blocking the illumination light. 18. Exposure of the substrate with the illumination light,
18. The projection exposure apparatus according to claim 1, further comprising a driving unit configured to relatively move the substrate and an image plane of the projection optical system in a direction along an optical axis thereof. 19. An illumination optical system for irradiating illumination light from a light source to a mask, and a projection optical system for projecting the illumination light onto a substrate, wherein the illumination light irradiates the mask pattern onto the substrate. In the projection exposure apparatus for transferring to the pattern, while increasing the light amount distribution of the illumination light on the Fourier transform surface for the pattern in the illumination optical system in a plurality of regions decentered from the optical axis of the illumination optical system, An optical member that defines a distance from the optical axis in the plurality of regions substantially equal to each other in accordance with a degree of fineness; and, during exposure of the substrate by the illumination light, an image plane of the substrate and the projection optical system. And a drive unit for relatively moving in a direction along the axis. 20. Two diffracted lights having different orders generated from the pattern by irradiation of light emitted from the respective regions are located on the pupil plane of the projection optical system at positions substantially equal in distance from the optical axis. 20. The projection exposure apparatus according to claim 16, wherein the position of each of the regions is determined so as to pass through. 21. An incident angle of light emitted from each of the regions to the mask, a diffraction angle of two diffracted lights of the same order generated from the pattern being θ, and a numerical aperture on the mask side of the projection optical system. Is NA _R , one of the two diffracted lights is s
2. The position of each of the regions is determined so that a relationship of in (θ−ψ) = NA _R is satisfied.
The projection exposure apparatus according to any one of 6, 17, 19, and 20. 22. The projection exposure apparatus according to claim 21, wherein said one diffracted light is substantially symmetric with respect to an optical axis of said projection optical system with respect to a zero-order diffracted light generated from said pattern. 23. A wavelength of the illumination light is λ, a pitch of the pattern is P, and an incident angle 光 of the light emitted from each of the regions to the mask satisfies a relationship of sinψ = λ / 2P. 23. The projection exposure apparatus according to claim 16, wherein the position of each of the regions is determined. 24. When the pattern is provided along first and second directions intersecting with each other, a 0th-order diffracted light generated from the pattern by irradiation of light emitted from each of the regions and a center of the 0th-order diffracted light are provided. One of the higher-order diffracted lights distributed in the first direction and one of the higher-order diffracted lights distributed in the second direction with the zero-order diffracted light as a center are arranged on the pupil plane of the projection optical system from their optical axes. The projection exposure apparatus according to any one of claims 16, 17, and 19 to 23, wherein the positions of the respective areas are determined so as to be distributed at substantially equal distances. 25. When the pattern is provided along first and second directions that intersect with each other, the plurality of regions include:
18. The optical system according to claim 16, wherein the optical axis intersects the optical axis on the Fourier transform plane and is separated by first and second axes defined along the first and second directions.
25. The projection exposure apparatus according to any one of 9 to 24. 26. A ratio of a numerical aperture of light emitted from each of the regions to a numerical aperture on a mask side of the projection optical system is 0.1 to 0.5.
18. The method according to claim 16, wherein the number is set to about 3.
The projection exposure apparatus according to any one of claims 19 to 25. 27. The projection exposure apparatus according to claim 1, further comprising a zoom lens system disposed between the light source and an optical integrator in the illumination optical system. . 28. An element manufacturing method using the projection exposure apparatus according to claim 1. 29. A projection exposure method for irradiating a mask with illumination light from a light source through an illumination optical system and exposing a substrate with the illumination light via a projection optical system, according to a pattern to be transferred onto the substrate. Selecting one of a plurality of optical integrators for differentiating the light amount distribution of the illumination light on the Fourier transform plane for the pattern in the illumination optical system, and connecting one end face of the selected optical integrator to the Fourier transform. A projection exposure method characterized in that the projection exposure method is arranged in the illumination optical system so as to substantially coincide with a surface. 30. A projection exposure method for irradiating a mask with illumination light from a light source through an illumination optical system and exposing a substrate with the illumination light via a projection optical system, wherein the pattern in the illumination optical system is The light amount distribution of the illumination light on the conversion surface is increased in a plurality of regions decentered from the optical axis of the illumination optical system, and the distance from the optical axis is substantially increased in the plurality of regions according to the fineness of the pattern. A projection exposure method defined equally, wherein the substrate and the image plane of the projection optical system are relatively moved in a direction along the optical axis during exposure of the substrate by the illumination light.