JP3298585B2 - Projection exposure apparatus and 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, and more particularly to a projection exposure apparatus used for transferring a circuit pattern of a semiconductor integrated device or a liquid crystal element.

[0002]

2. Description of the Related Art For forming a circuit pattern of a semiconductor element or the like,
In general, a process called a photolithographic technique is required. In this step, a method of transferring a reticle (mask) pattern onto a sample substrate such as a semiconductor wafer is usually employed. 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 exposure apparatus, a circuit pattern to be transferred drawn on a reticle is projected and imaged 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 fiber is used, and the intensity distribution of illumination light applied to the reticle is made uniform. In order to optimize the uniformity, when a fly-eye lens is used, the reticle-side focal plane of the fly-eye lens and the reticle pattern plane are almost connected by a Fourier transform, and the reticle-side focal plane And the focal plane on the light source side are connected by a Fourier transform.

Therefore, the pattern surface of the reticle and the focal plane on the light source side of the fly-eye lens (more precisely, the focal plane on the light source side of each lens of the fly-eye lens) are connected in an imaging relationship (conjugate relationship). I have. 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,
Illuminance uniformity on the reticle can be improved.

In a conventional projection type exposure apparatus, the distribution of the amount of illumination light flux incident on the incident surface of an optical integrator such as the fly-eye lens described above is substantially circular (or rectangular) around the optical axis of the illumination optical system. ) To make it almost uniform. FIG. 9 is a diagram schematically showing a configuration from the optical integrator to the wafer of the above-mentioned conventional projection exposure apparatus. The illumination light beam L130 illuminates the reticle pattern 17 of the reticle 16 via the fly-eye lens 11, the spatial filter 12, and the condenser lens 15 in the illumination optical system.

Here, the spatial filter 12 is a reticle-side focal plane 11b of the fly-eye lens 11, that is, the reticle 1
6, a secondary light source disposed in or near the Fourier transform plane (hereinafter abbreviated as a pupil plane), having an opening in a substantially circular area centered on the optical axis AX of the projection optical system, and formed in the pupil plane ( (Surface light source) Limit the image to a circle. At this time, the ratio between the numerical apertures of the illumination optical systems 11, 12, and 15 and the reticle-side numerical aperture of the projection optical system 18, a so-called σ value, is determined by an aperture stop (for example, the aperture diameter of the spatial filter 12). 0.
About 3 to 0.6 is common.

The illumination light beam L130 is diffracted by the pattern 17 patterned on the reticle 16, and the pattern 1
7 generates a 0th-order diffracted light Do, a + 1st-order diffracted light Dp, and a -1st-order diffracted light Dm. The respective diffracted lights Do, Dm, Dp are condensed by the projection optical system 18 and generate interference fringes on the wafer 20. This interference fringe is an image of the pattern 17. At this time, the angle θ (reticle side) between the 0th-order diffracted light Do and the ± 1st-order diffracted lights Dp and Dm is sin θ = λ / P (λ: exposure wavelength,
P: pattern pitch). Here, a solid line representing a light beam represents a principal ray of light emitted from one point.

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 Dp, D
m cannot pass through the projection optical system. Then, wafer 2
Only zero-order diffracted light Do reaches zero, and no interference fringes occur. That is, when sin θ> NA _R , an image of the pattern 17 cannot be obtained, and the pattern 17 cannot be transferred onto the wafer 20.

From the above, in the conventional exposure apparatus, sin θ = λ / P ≒ NA _R , and the pitch P is given by the following equation. P ≒ λ / NA _R (1) In the case of a 1: 1 line-and-space pattern, the minimum pattern size is half the pitch P, so the minimum pattern size is about 0.5 · λ / NA _R , but actually In photolithography, a certain depth of focus is required due to the curvature of the wafer, the influence of the step on the wafer due to the process, or the thickness of the photoresist itself. For this reason, the practical minimum resolution pattern size is k · λ / N
Represented as A. Where k is called the process coefficient
It is about 0.6 to 0.8.

Also, a numerical aperture NA of the projection optical system on the reticle side.
_Since the ratio between _R and the numerical aperture NA _W on the wafer side is the same as the projection magnification of the projection optical system, the minimum resolution pattern size on the reticle is k · λ / NA _R and the minimum pattern size on the wafer is k · λ / NA _W = k · λ / M · NA _R (where M is the projection magnification (reduction ratio)).

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 a projection optical system having a larger numerical aperture. Of course, efforts can be made to optimize both the wavelength and the numerical aperture. A so-called phase shift reticle, which shifts the phase of the transmitted light from a specific portion of the transmitted portion of the reticle circuit pattern by π from the phase of the transmitted light from another transmitted portion, is a so-called phase shift reticle.
No. 11 has been proposed. Use of this phase shift reticle enables transfer of a finer pattern than in the past.

Further, an inclined illumination method for illuminating a reticle with light inclined by a predetermined angle has also been proposed. This oblique illumination method is basically the same as a method of limiting the shape of a secondary light source on a surface equivalent to the Fourier transform of a reticle pattern or a surface in the vicinity thereof (hereinafter referred to as a “deformed light source method”), which was announced at the fall meeting of the Japan Society of Applied Physics in 1991. Is equivalent to

[0013]

However, in the conventional exposure apparatus, shortening the wavelength of the illumination light source (for example, 200 nm or less) is difficult because there is no suitable optical material usable as a transmission optical member. It is difficult at the moment for reasons.

Further, 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. Even if it is possible to make the aperture larger than the current situation, the depth of focus represented by ± λ / 2NA ² decreases rapidly with the increase of the numerical aperture, and the depth of focus required for actual use becomes further smaller. The problem becomes remarkable.

On the other hand, the phase shift reticle has many problems such as a high manufacturing cost due to the complicated manufacturing process, and no inspection and repair method has been established yet. In the modified light source method, the shape of the secondary light source is limited by providing a light-shielding plate having a predetermined opening on the surface corresponding to the Fourier transform of the reticle pattern or in the vicinity thereof (particularly, on the exit end side of the fly-eye lens). In addition, there is a problem that light quantity loss and deterioration of uniformity of illuminance deteriorate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a projection exposure apparatus and method capable of obtaining a high resolution and a large depth of focus without loss of light amount or deterioration of uniformity of illuminance even when a normal reticle is used. The purpose is to provide.

[0017]

The principle of the projection exposure apparatus of the present invention is shown in FIG. FIG.
In FIG. 9, the same members as those in the conventional art (FIG. 9) are denoted by the same reference numerals. In FIG. 8, fly-eye lenses 11A and 11B as optical integrators are positioned such that their reticle-side focal planes 11b are substantially Fourier transform planes with respect to a circuit pattern (reticle pattern) 17 on a reticle 16 (the projection optical system 18). (A position conjugate with the pupil plane 19) and the fly-eye lenses 11A and 11B
Are dispersedly arranged in a plurality of fly-eye lenses.

In order to make the illumination light amount distribution on the reticle-side focal plane 11b of the fly-eye lenses 11A and 11B substantially zero at positions other than the individual fly-eye lens positions of the plurality of fly-eye lenses 11A and 11B, A light shielding plate 12 is provided on the light source side of the lens. Therefore, the reticle-side focal plane 11b of the fly-eye lenses 11A and 11B
The illumination light amount distribution of each fly-eye lens 11A, 1
It exists only at the position 1B, and becomes almost zero otherwise.

Since the reticle-side focal plane 11b of the fly-eye lenses 11A and 11B is substantially equal to the Fourier transform plane for the reticle pattern 17, the fly-eye lens 11
The light quantity distribution (position coordinates of the light beam) on the reticle-side focal plane 11b of A and 11B corresponds to the incident angle の of the illumination light beam with respect to the reticle pattern 17. Therefore, by adjusting the individual positions (positions in a plane perpendicular to the optical axis) of the fly-eye lenses 11A and 11B, the incident angle of the illumination light beam incident on the reticle pattern 17 can be determined. Here, it is desirable that the fly-eye lenses 11A and 11B are arranged symmetrically with respect to the optical axis AX.

A projection exposure apparatus according to a first aspect of the present invention includes an illumination optical system for irradiating illumination light from a light source (1) onto a mask (16), and an image of a pattern (17) of the mask on a substrate. (20) a projection optical system (18) for projecting the light onto the projection optical system. Then, the light amount distribution of the illumination light on a predetermined plane (pupil plane of the illumination optical system) which substantially has a Fourier transform relationship with respect to the pattern of the mask in the illumination optical system is represented by the optical axis (AX) of the illumination optical system. ), The distance from the optical axis is equal, the position on the predetermined surface is set in accordance with the pattern, and the intensity is increased in a plurality of regions, and the intensities of the light beams emitted from the plurality of regions are made substantially equal. Illumination light generating means (5, 6, 9)
And the illumination light generation means includes a pair of prisms (5a, 5b) that are relatively movable along the optical axis of the illumination optical system. The interval between the pair of prisms may be adjusted according to the distance between the optical axis of the illumination optical system and the plurality of regions.

According to the projection exposure method of the present invention, the mask (16) is irradiated with illumination light from the light source (1) through the illumination optical system, and is also projected through the projection optical system (18). The substrate (20) is exposed with illumination light. Then, the light amount distribution of the illumination light on a predetermined plane (pupil plane of the illumination optical system) which substantially has a Fourier transform relationship with the pattern of the mask in the illumination optical system is represented by the optical axis (A) of the illumination optical system.
X), the distance from the optical axis is equal, the position on the predetermined surface is set in accordance with the pattern, and the intensity is increased in a plurality of regions. The distance between the optical axis of the illumination optical system and the plurality of regions is set using a pair of prisms (5a, 5b) that can move relatively along the optical axis of the illumination optical system.

Therefore, in the invention according to claims 1 and 30,
A mask pattern can be transferred onto a substrate with a high resolution and a large depth of focus, and the light quantity loss accompanying the setting of the light quantity distribution of the illumination light can be greatly reduced. Note that the distance between the optical axis of the illumination optical system and the plurality of regions is variable, the plurality of regions are moved in a radial direction around the optical axis of the illumination optical system on a predetermined surface, or transferred onto a substrate. The interval between the pair of prisms may be adjusted to change the light amount distribution according to the power pattern.

The first prism (5a) of the pair of prisms into which the illumination light is incident has a convex exit surface, and the second prism (65b) from which the illumination light exits has a concave entrance surface. It may be. Furthermore, the first
The entrance surface of the prism and the exit surface of the second prism may each be a plane substantially perpendicular to the optical axis of the illumination optical system, or the first prism may be movable in a direction perpendicular to the optical axis of the illumination optical system. Each of the pair of prisms may be a polyhedral prism, or may be arranged almost conjugate with a predetermined surface in the illumination optical system. Further, it is desirable that the pair of prisms is disposed between the light source and the optical integrator in the illumination optical system. Further, the illumination light emitted from the pair of prisms may be focused on the incident surface of the optical integrator by using the lens system (9).

According to the present invention, a pattern can be transferred onto a substrate with a high resolution and a large depth of focus. Hereinafter, the reason will be briefly described. The circuit pattern (17) drawn on the reticle (mask) generally contains many periodic patterns. Therefore, one of a plurality of regions where the light amount distribution is increased on the Fourier transform plane (pupil plane) in the illumination optical system, for example, one fly-eye lens 11 shown in FIG.
A 0th-order diffracted light component Do, ± 1st-order diffracted light component Dp,
Dm and higher-order diffracted light components are generated in the direction of the diffraction angle corresponding to the fineness (pitch) of the pattern. At this time, as shown in FIG. 8, the illumination light flux (principal ray) L120 is incident on the reticle 16 at an angle ψ inclined with respect to the optical axis, so that the generated diffracted light components of each order are also illuminated vertically. Are generated from the reticle pattern 17 with an inclination (angle shift) as compared with

The illuminating light L120 is diffracted by the reticle pattern 17 and travels in a direction inclined by ψ with respect to the optical axis AX, the 0th-order diffracted light Do, the + 1st-order diffracted light Dp inclined by θp with respect to the 0th-order diffracted light Do, and 0 ° A -1st-order diffracted light Dm inclined by θm with respect to the second-order diffracted light Do is generated. Accordingly, the + 1st-order diffracted light Dp travels in the direction of an angle (θp + ψ) with respect to the optical axis AX, and the −1st-order diffracted light Dm has an angle (θm) with respect to the optical axis AX.
-Proceed in the direction of ψ).

At this time, the diffraction angles θp and θm are represented by sin (θp + ψ) −sinψ = λ / P (2) sin (θm−ψ) + sinψ = λ / P (3)

Here, it is assumed that both the + 1st-order diffracted light Dp and the -1st-order diffracted light Dm are transmitted through the pupil 19 of the projection optical system 18. When the diffraction angle increases with miniaturization of the reticle pattern 17, first-order diffracted light Dp traveling in the direction of the angle (θp + ψ) cannot pass through the pupil 19 of the projection optical system 18. That is, a relationship of sin (θp + ψ)> NA _R is established. However, since the illumination light L120 is incident obliquely with respect to the optical axis AX, even if the diffraction angle increases, −1
The next-order diffracted light Dm can enter the projection optical system 18. That is, the relationship sin (θm−ψ) <NA _R is satisfied. Therefore, interference fringes are generated on the wafer 20 by two light beams of the 0th-order diffracted light Do and the -1st-order diffracted light Dm. This interference fringe is an image of the reticle pattern 17. When the reticle pattern 17 has a 1: 1 line and space, the image of the reticle pattern 17 is patterned on the resist applied on the wafer 20 with a contrast of about 90%. It becomes possible.

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

For example, if sinψ is determined to be about 0.5 × NA _R , the minimum pitch of the pattern on the reticle that can be transferred is P = λ / (NA _R + 0.5NA _R ) = 2λ / 3NA _R. (6)

On the other hand, as shown in FIG.
Of the illumination light on the pupil plane of the projection optical system 18 is the optical axis AX
In the case of the conventional exposure apparatus which is a circular area centered at, the resolution limit is P ≒ λ / NA _R as shown in the equation (1). From the above, it is understood that a higher resolution than the conventional exposure apparatus can be realized.

Next, a reticle pattern is irradiated with a light beam in a specific incident direction and an incident angle, and a focus is formed by a method of forming an image pattern on a wafer using a 0th-order diffracted light component and a 1st-order diffracted light component. The reason why the depth is increased will be described. When the wafer 20 coincides with the focal position (best image plane) of the projection optical system 18 as shown in FIG. 8, each diffracted light that exits one point in the reticle pattern 17 and reaches one point on the wafer 20 Have the same 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 of the 0th-order diffracted light component and other diffracted light components are different. Equal, mutual wavefront aberration is also zero.

However, when the wafer 20 is in a defocused state where it does not coincide with the focal position of the projection optical system 18, FIG.
In the conventional apparatus as shown in FIG. 1, the optical path length of high-order diffracted light obliquely incident on the projection optical system is 0
For the next diffracted light, it is short before the focal point (away from the projection optical system 18) and long behind the focal point (approaching the projection optical system 18), and the difference depends on the difference in the incident angle. Therefore, the respective diffracted lights mutually form a wavefront aberration, and blur occurs before and after the focal position.

The wavefront aberration due to the above-mentioned defocus is represented by ΔF, the defocus amount from the focal position of the wafer 20, and the sine of the incident angle θ _W when each diffracted light is incident on the wafer.
When (r = sinθ _W), it is an amount given by ΔFr ^2/2. At this time, r represents the distance of each diffracted light from the optical axis AX on the pupil plane 19. In the conventional projection exposure apparatus shown in FIG. 9, since the 0th-order diffracted light Do passes near the optical axis AX, r = 0, and the ± 1st-order diffracted lights Dp and Dm are r = M ·
λ / P (M is the magnification of the projection optical system).

Therefore, the 0th-order diffracted light Do and ± 1st-order diffracted light D
The wavefront aberration due to defocus with p and Dm is ΔF · M
^{2 (λ} / P) becomes a ^2/2. On the other hand, in the projection exposure apparatus according to the present invention, as shown in FIG. 8, the 0th-order diffracted light component Do is generated in a direction inclined from the optical axis AX by an angle ψ.
The distance of the 0th-order diffracted light component from the optical axis AX at 9 is r =
M · sinψ. The distance of the -1st-order diffracted light component Dm from the optical axis on the pupil plane is r = M · sin (θm−ψ).
Becomes Then, at this time, sinψ = sin (θm-ψ)
Then, the relative wavefront aberration due to the defocus of the 0th-order diffracted light component Do and the -1st-order diffracted light component Dm becomes zero, and even if the wafer 20 is slightly shifted from the focal position in the optical axis direction, the image blur of the pattern 17 is It will not be as large as in the past. That is, the depth of focus increases. Further, as in Expression (3), since sin (θm−ψ) + sin 式 = λ / P, the incident angle 照明 of the illumination light beam L120 on the reticle 16 is
If the relationship of sinψ = λ / 2P with respect to the pitch P of the pattern, the depth of focus can be increased.

FIG. 8 used to explain the principle of the present invention
3 shows a state in which two fly-eye lenses maintain positional symmetry with respect to the optical axis AX. Even if the symmetry of the position of the fly-eye lens is maintained in this way,
The light amounts emitted from the two fly-eye lenses 11A and 11B are not always equal. Therefore, in order to maintain symmetry in consideration of the position of the fly-eye lens and the light amount of the light beam from that position, the light amounts of the light beams from both fly-eye lenses need to be equal. If this symmetry is not maintained, the directional center of gravity of the illumination light beam on the wafer conjugate plane (the sum of the position vector from the optical axis to the light beam on the pupil plane of the projection optical system multiplied by the light amount of each light beam) is calculated from the optical axis. It will come off. That is, the telecentricity of the projection optical system on the wafer side is not maintained, and a lateral shift (a so-called telecentric shift) of the pattern image occurs at the time of defocusing.

Therefore, for example, of a pair of prisms (also referred to as light beam splitting members) disposed between the light source and the optical integrators (fly-eye lenses 11A and 11B), the first prism (5a) disposed on the light source side. May be movable in a direction substantially perpendicular to the optical axis of the illumination optical system, and the intensity of each light beam emitted from the pair of prisms may be adjusted by the relative movement between the illumination light from the light source and the first prism. This makes it possible to make the intensity of the light beam emitted from each region (each fly-eye lens in FIG. 8) where the light amount distribution is increased on the Fourier transform surface in the illumination optical system substantially equal. At this time, an illuminometer (21) for measuring the intensity of the light beam from each fly-eye lens may be provided, and the intensity of each light beam may be adjusted based on the measurement result.

[0037]

FIG. 1 is a diagram showing a schematic configuration of a projection type exposure apparatus (stepper) according to an embodiment of the present invention. In this configuration, as an optical member (part of a light beam splitting member) for concentrating the light amount distribution of the illumination light on a predetermined area of the light source side focal plane 11a of each of the fly-eye lenses 11A and 11B,
The polyhedral prism 5 is provided.

The illuminating light beam generated by the mercury lamp 1 is focused on the second focal point f ₀ of the elliptical mirror 2 and then radiated to the polyhedral prism 5 via the mirror 3 and a lens system 4 such as a relay system. The illumination method at this time may be the Koehler illumination method or the critical illumination. The luminous flux generated from the polyhedral prism 5 is intensively incident on each of the fly-eye lenses 11A and 11B by the relay lens 9. At this time, the light source side focal plane 1 of the fly-eye lenses 11A and 11B
1a and the polyhedral prism 5 have a substantially Fourier transform relationship via the relay lens 9. In FIG. 1, the illumination light to the polyhedral prism 5 is illustrated as a parallel light flux. However, since the light is actually a divergent light flux, the light flux incident on the fly-eye lenses 11A and 11B has a certain size (area). I have.

On the other hand, the reticle-side focal planes 11b of the fly-eye lenses 11A and 11B are arranged in a 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. Have been. The individual fly-eye lenses 11A and 11B are independently movable in a direction perpendicular to the optical axis AX, and are held by movable members therefor. The details will be described later. It is desirable that the individual fly-eye lenses 11A and 11B have the same shape and the same material (refractive index).

Further, each lens element of each of the fly-eye lenses 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 this is an example of the case, the lens element of the fly-eye lens does not have to strictly satisfy this relationship, and may be a plano-convex lens, a convex-planar lens, or a plano-concave lens.

Incidentally, the light source side focal plane 11 of the fly-eye lens
a and the reticle-side focal plane 11b naturally have a Fourier transform relationship. Therefore, in the case of the example of FIG. 1, the reticle-side focal plane 11b of the fly-eye lens, that is, the exit surfaces of the fly-eye lenses 11A and 11B have an imaging relationship (conjugate) with the polyhedral prism 5.

FIG. 2 is a diagram schematically showing a configuration from the fly-eye lenses 11A and 11B of the projection type exposure apparatus to the projection optical system 18. The reticle-side focal plane 11b of the fly-eye lens Fourier transform surface 1
2c. Also, at this time, an optical system that makes the reticle-side focal plane 11b and the reticle pattern 17 have a Fourier transform relationship is represented as a single lens 15a. Further, the distance from the fly-eye lens-side principal point H of the lens 15a to the reticle-side focal plane 11b of the fly-eye lenses 11A and 11B and the distance from the reticle-side principal point H 'of the lens 15a to the reticle pattern 17 are both f. Suppose there is.

The luminous flux emitted from the reticle-side focal plane 11b of the fly-eye lenses 11A and 11B illuminates the reticle 16 with uniform illuminance distribution via the condenser lenses 13, 15 and the mirror 14. Shield plate 12
A and 12B are fly-eye lenses 11A and 11B, respectively.
It is movable corresponding to each position of B. Therefore, the illumination light beams from the fly-eye lenses 11A and 11B can be arbitrarily blocked and transmitted. For this reason, the illuminating light illuminating the reticle pattern 17 is transmitted to the luminous flux (2) from one of the fly-eye lenses 11A and 11B.
Luminous flux from the next light source image).
For example, when the intensity of a light beam is measured using an illuminometer 21 having a light receiving surface on a conjugate surface with the surface of the wafer 20, the intensity of the light beam from each fly-eye lens can be measured independently.

The illuminometer is not limited to the one arranged on the wafer conjugate plane. For example, a plane conjugate with the reticle-side focal plane 11b of the fly-eye lens is formed on the back surface of the mirror 14, and two sensors are provided there. You may arrange and measure.
In that case, the intensity of each light beam from the fly-eye lenses 11A and 11B can be measured simultaneously,
A is not needed.

The diffracted light generated from the reticle pattern 17 on the reticle 16 thus illuminated is condensed and imaged by the telecentric projection optical system 18 as described with reference to FIG. Pattern 1
7 is transferred. The illumination light beam is divided by using the above-mentioned polyhedral prism 5 and the light beam is divided into a fly-eye lens 11.
When focusing on a specific position (fly-eye lens) in the light source side focal plane of A, 11B, the concentration position changes depending on the inclination angle and directionality of the polyhedral prism 5. Accordingly, the inclination angle and directionality of the polyhedral prism 5 are determined so that the illumination light is concentrated on the positions of the fly-eye lenses 11A and 11B.

In the above embodiment, the polyhedral prism 5 and the focal plane on the light source side of the fly-eye lenses 11A and 11B have a Fourier transform relationship, but may have an image forming relationship. However,
By making the relationship of the Fourier transform, it is possible to prevent the illuminance uniformity on the reticle 16 from deteriorating due to dust or the like on the polyhedral prism 5. Although the illumination light beam is divided into two light beams by the polyhedral prism 5 in the figure, the light beam can be divided into more light beams by increasing the number of surfaces of the polyhedral prism.

The polyhedral prism 5 in FIG. 1 is held by an active member 6 and is movable in a direction substantially perpendicular to the optical axis AX (vertical direction on the paper) (details will be described later). At this time, when the polyhedral prism 5 is moved in a direction substantially perpendicular to the optical axis AX, the division position of the light beam incident on the polyhedral prism 5 (the relative position between the polyhedral prism 5 and the incident light beam) changes, so that a plurality of divided polyhedron prisms 5 are obtained. The light amount ratio of the light beam can be changed without loss of light amount. At this time, the active member 6 is controlled by the drive system 51. The drive system 51 also controls the light-shielding plates 12A and 12B to enter and exit the optical paths (near the exit surfaces of the fly-eye lenses). Further, if the fly-eye lenses 11A and 11B are movable, the fly-eye lenses are also moved.

In FIG. 1, a wafer holder 22 for holding a wafer 20 is movable by a wafer stage 23 in a plane perpendicular to the optical axis AX. An illuminometer 21 is provided on the wafer stage 23. The illuminometer 21 is a sensor that collectively receives light in the entire projection field, and its light receiving surface is provided in a plane substantially coincident with the wafer surface. This illuminometer 21 can measure the illumination light intensity at a position conjugate with the image plane on the wafer. Therefore, by operating the above-mentioned light shielding plates 12A and 12B to block all illumination light beams from one of the fly-eye lenses 11A and 11B except for one of them, the light beam from one fly-eye lens is The intensity can be measured. By performing this measurement for each fly-eye lens, the intensity of the light beam from each fly-eye lens can be known. It is preferable that the reticle 16 is not loaded at the time of intensity measurement, but the measurement may be performed with the reticle inserted.

The measured value of each light beam is compared by the main control system 21. The relationship between the intensity of the illumination light and the driving amount of the active member 6 is registered in the main control system 21 in advance as a table value, and the main control system 21 operates the active member 6 so that the intensity of each light beam is equal. . Thereby, the intensity of the light beam from each fly-eye lens can be made equal.

The arrangement of each fly-eye lens is symmetric with respect to the optical axis AX. Therefore, the sum of the position vector from the optical axis to each light beam on the pupil plane of the above-described projection optical system multiplied by the light amount of each light beam (the center of gravity in the direction) becomes zero,
The aforementioned telecentric shift can be made zero.

By the way, the mercury lamp 1, which is a light source, has a limited use time (lifetime), and at present, the mercury lamp 1 is used after being replaced with a new one approximately every 600 hours. Mercury lamps include
There are individual differences that occur at the manufacturing stage, and the orientation characteristics of the light amount and the like differ from lamp to lamp. Therefore, even if the intensity of the luminous flux from each fly-eye lens was equal when the previous lamp was used, a change in the orientation characteristics and the like occurred by replacing the lamp, and the intensity of the luminous flux from each fly-eye lens was equal. May not be possible. This also means 1
It can also be caused by a change over time during use of individual mercury lamps. Therefore, the adjustment of the light beam splitting means is as follows.
It is good to carry out every lamp replacement or every 100 hours, for example, during lamp use.

Incidentally, it is desirable that the position of the secondary light source image in the reticle-side focal plane of the fly-eye lens can be changed according to the pitch (periodicity) of the reticle pattern used. An embodiment in which the fly-eye lens is movable will be described below. FIG. 3 is a view of the movable portion of the fly-eye lens viewed from the optical axis direction, and FIG. 4 is a view of the movable portion of the fly-eye lens viewed from a direction perpendicular to the optical axis. Fig. 3 as multiple fly-eye lenses
Then, four fly-eye lenses 11A, 11B, 11C,
11D is arranged at substantially the same distance from the optical axis. Each of the fly-eye lenses 11A, 11B, 11C and 11D is shown in FIG. 3 as being composed of 32 lens elements. However, the present invention is not limited to this. May be used as a fly-eye lens.

3 and 4, the fly-eye lenses 11A, 11B, 11C, and 11D are each provided with a jig 80.
A, 80B, 80C, and 80D are held by jigs 80A, 80B, 80C, and 80D.
A, 70B, 70C, 70D via movable member 71A,
Supported by 71B, 71C and 71D, respectively. The support rods 70A, 70B, 70C, 70D can be expanded and contracted in the radial direction about the optical axis AX by driving elements such as motors and gears included in the movable members 71A, 71B, 71C, 71D. Also, the movable member 71A,
71B, 71C and 71D themselves are also fixed guides 72A and 7D.
2B, 72C, 72D, so that the individual fly-eye lenses 11A, 11B, 11C, 11
D is independently movable to any position in a plane perpendicular to the optical axis AX.

Further, the light shielding plates 12A and 12B can also be moved according to the movement of the fly-eye lenses 11A and 11B.
Irrespective of the positions of the fly-eye lenses 11A and 11B, only light from an arbitrary fly-eye lens can be transmitted, and all other light can be blocked. Further, jigs 80A, 80B for holding the respective fly-eye lenses 11A, 11B
Has light-shielding blades 81A and 81B, respectively, the opening of the light-shielding plate 12 as shown in FIG. 8 is considerably larger than the diameter of the fly-eye lens. In addition, each shading blade 81
When A and 81B are slightly displaced in the optical axis direction, the restriction imposed on the movement range of each fly-eye lens is reduced.

Next, the configuration of the polyhedral prism 5 will be described with reference to FIG. The polyhedral prism 5 includes two polyhedral prisms 5a and 5b, and at least the concave polyhedral prism 5a is movable in an in-plane direction perpendicular to the optical axis AX. The prism 5a is provided on the active member 6a via the holder 7a.
Is provided on the fixture 8. The active member 6 is a prism 5
a is moved in an in-plane direction perpendicular to the optical axis AX. On the other hand, the prism 5b is provided on the fixture 8 via the holder 7b. Each of the prisms 5a and 5b is provided with a fixture 8
It is movable in the optical axis AX direction by a driving unit provided therein, and the distance between the prism 5a and the prism 5b in the optical axis AX direction can be made variable.

When equalizing the intensity of each illumination light beam as described above, at least the prism 5a is moved by a predetermined amount in the in-plane direction perpendicular to the optical axis AX. When the concave prism 5a is composed of a plurality of optical elements, at least a part thereof may be movable. Note that the dotted line in the figure shows the case where the prism 5a moves, and at this time, the two light beams
In the case of a large shift from X, a parallel plate glass may be provided in each optical path between the prism 5b and the lens 9a to correct the shift amount of each light beam from the optical axis AX.

Incidentally, as described above, the fly-eye lens 1
When 1A to 1D move, the position through which a light beam emitted from a light beam splitting member such as a polyhedral prism passes (a position in a plane perpendicular to the optical axis around the optical axis AX) also changes in accordance with the movement of the fly-eye lens. Need to change. In this case, by changing the distance between the prism 5a and the prism 5b, the distance of each split light beam from the optical axis can be changed. Further, by rotating the prisms 5a and 5b about the optical axis AX, the position of the light flux in the circumferential direction around the optical axis can be changed.

The positions of the fly-eye lenses 11A, 11B, 11C and 11D (positions in a plane perpendicular to the optical axis) shown in FIGS. 3 and 4 are determined according to the reticle pattern to be transferred. (Change) is good. That is, as described in the section of the operation, the illumination light beam from each fly-eye lens is incident at such an angle that the optimum resolution for the fineness (pitch) of the pattern to be transferred and the effect of improving the depth of focus can be obtained. It is sufficient to make the light incident on the reticle pattern with ψ.

Next, a specific example of determining the position of each fly-eye lens will be described with reference to FIG. FIG. 6 (A),
(C) is a diagram showing an example of a partial pattern formed in the reticle pattern 17. FIG. 6 (B) shows a pattern suitable for illuminating a pattern as shown in FIG. 6 (A).
The position of the center of each fly-eye lens on the Fourier transform plane of the reticle pattern (or the pupil plane of the projection optical system) (corresponding to the position of the local maximum value of the light quantity distribution in the Fourier transform plane in the present invention) is shown. Similarly, FIG. 6D is a diagram showing the center position of each fly-eye lens, which is optimal for illuminating the pattern as shown in FIG. 6C.

FIG. 6A shows a so-called one-dimensional line-and-space pattern in which a transparent portion and a light-shielding portion extending in a band shape in the Y direction have the same width and are regularly arranged at a pitch P in the X direction. In. At this time, the optimum position of each fly-eye lens is determined by the Fourier transform plane 12 as shown in FIG.
An arbitrary position on the line segment Lα in the Y direction assumed within c and on the line segment Lβ. FIG. 6B shows a reticle pattern 17.
FIG. 9 is a view of the Fourier transform surface 12c (the reticle-side focal plane 11b of the fly-eye lens) of the reticle pattern 17 viewed from the optical axis AX direction, and the coordinate system X, Y in the surface 12c is viewed from the same direction. It is the same as FIG.

In FIG. 6B, the distances α and β from the center C through which the optical axis AX passes to the respective line segments Lα and Lβ are α = β.
where β is the exposure wavelength and α = β = f · λ /
Equivalent to 2P. If these distances α and β can be expressed as f · sinψ, then sinψ = λ / 2P, which coincides with the numerical value described in the section of the operation. Therefore, each center of each fly-eye lens (2
If the positions of the respective centers of gravity of the light amount distribution of the next light source image are on the line segments Lα and Lβ, when the light beam from each fly-eye lens is applied to the line and space pattern as shown in FIG. Either of the generated ± 1st-order diffracted lights and the 0th-order diffracted light are transmitted to the projection optical system pupil plane 19.
At a position that is approximately equidistant from the optical axis AX. Therefore, as described above, the line and space pattern (FIG. 6)
The depth of focus for (A)) can be maximized, and high resolution can be obtained.

Next, FIG. 6C shows a case where the reticle pattern is a so-called two-dimensional island pattern, and the pitch of the pattern in the X direction is Px and the pitch in the Y direction is Py. FIG. 6D is a diagram showing an optimum position of each fly-eye lens when illuminating such a pattern. The relationship between the coordinate systems X and Y in FIG. 6C is shown in FIGS.
This is the same as the relationship of (B). When illumination light is incident on a two-dimensional pattern as shown in FIG. 6C, diffracted light is generated in a two-dimensional direction according to the periodicity of the pattern in the two-dimensional direction (Px in the X direction and Py in the Y direction). Also in this case, ± 1
If any one of the diffracted light beams and the zero-order diffracted light beam are made to be substantially equidistant from the optical axis AX on the pupil plane 19 of the projection optical system, the depth of focus can be maximized. That is, since the pitch in the X direction of the pattern in FIG. 6C is Px, α = β = f · λ / 2P as shown in FIG.
If the center of each fly-eye lens is located on the line segments Lα and Lβ that are x, the depth of focus can be maximized for the X-direction component of the pattern. Similarly, γ = ε = f · λ / 2P
If the center of each fly-eye lens is located on the line segments Lγ and Lε that become y, the depth of focus can be maximized for the pattern Y-direction component.

As described above, when the illumination light beam from the fly-eye lens disposed at each position shown in FIG. 6B or 6D enters the reticle pattern 17, the + 1st-order diffracted light component D
Either p or the -1st-order diffracted light component Dm and the 0th-order diffracted light component Do pass through an optical path at a pupil plane 19 in the projection optical system 18 which is substantially equidistant from the optical axis AX. Therefore, as described in the operation section, a projection type exposure apparatus having a high resolution and a large depth of focus can be realized.

As described above, 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 the + 1st-order diffracted light component from the pattern or the -1st order The center of each fly-eye lens is arranged at a position where two light beams, one of the folded light components and the 0th-order diffracted light component, pass through an optical path that is substantially equidistant from the optical axis AX on the pupil plane 19 in the projection optical system. do it.

In the pattern examples of FIGS. 6A and 6C, the ratio (duty ratio) between the light-shielding portion and the transmitting portion is 1: 1. The folding light becomes stronger. Therefore, attention was paid only to the relationship between one of the ± 1st-order diffracted lights and the 0th-order diffracted light. However, in the case of a pattern having a duty ratio different from 1: 1 or the like, the positional relationship between another diffracted light, for example, one of the ± 2nd-order diffracted light and the 0th-order diffracted light is different from the optical axis AX on the projection optical system pupil plane 19. The distances may be substantially equal.

Further, the reticle pattern 17 is shown in FIG.
When a two-dimensional periodic pattern is included as in (C), when focusing on one specific 0th-order diffracted light component, on the pupil plane 19 of the projection optical system, the one 0th-order diffracted light component is centered in the X direction. There may be a first or higher order diffracted light component distributed in the Y direction and a first or higher order diffracted light component distributed in the Y direction.

Therefore, assuming that a two-dimensional pattern is favorably imaged with respect to one specific zero-order diffracted light component, one of the high-order diffracted light components distributed in the X direction and one of the high-order diffracted light components distributed in the Y direction. The three diffracted light components, one of the diffracted light components of the first order and a specific diffracted light component of the zeroth order, are arranged on the pupil plane 19 along the optical axis AX.
The position of a specific zero-order diffracted light component (one fly-eye lens) may be adjusted so as to be distributed at substantially the same distance from. For example, the center position of the fly-eye lens in FIG. 6D may be matched with any of the points Pζ, Pη, Pκ, and Pμ. Each of the points Pζ, Pη, Pκ, and Pμ is a line segment Lα or Lβ (the optimal position for the periodicity in the X direction, ie, X
A position where one of the ± 1st-order diffracted lights in the direction and the 0th-order diffracted light are substantially equidistant from the optical axis on the projection optical system pupil plane 19) and the line segment L
Since this is the intersection with γ or Lε (the optimum position for the periodicity in the Y direction), the light source position is the optimum in both the X direction and the Y direction.

In the above embodiment, a two-dimensional pattern is assumed to have a two-dimensional direction at the same position on the reticle. However, a plurality of patterns having different directions at different positions in the same reticle pattern may be used. The above method can be applied even when it exists.

When the pattern on the reticle has a plurality of directions or finenesses, the optimum position of the fly-eye lens depends on each directionality and fineness of the pattern as described above. Alternatively, a fly-eye lens may be arranged at an average position of each optimum position. The average position may be a weighted average that takes into account the weight according to the fineness and importance of the pattern. When the fly-eye lens is moved as described above, it is desirable to measure the intensity of the luminous flux from each fly-eye lens with the illuminometer 21 and confirm whether each of them has a predetermined intensity.

As described above, when the directionality of the cycle of the reticle pattern is taken into account, the above-mentioned information can be input from the keyboard 52 in FIG. When the input information is the directionality of the pattern, the position of each fly-eye lens may be determined by the main control system 50 in accordance with the information.

The numerical aperture of the light beam emitted from each fly-eye lens to the reticle is preferably about 0.1 to 0.3 as the σ value. If the σ value is too small, the illuminance tends to be reduced or illuminance unevenness occurs. If the σ value is too large, the effect of high resolution and large depth of focus according to the present invention is reduced. In the above embodiments, the mercury lamp 1 was used as the light source. Alternatively, another bright line lamp, a laser (KrF or the like) light source, or a light source 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. Further, 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 the same applies to a one-sided telecentric system and a non-telecentric system.
In addition, monochromatic means such as an interference filter may be provided in the illumination optical system in order to use only light of a specific wavelength among the illumination light generated from the light source.

For uniformizing the illumination light, the light source side focal plane 1 of the fly-eye lenses 11A, 11B, 11C, 11D
The illumination light may be made uniform by using a light scattering member such as a diffusion plate or an optical fiber bundle near 1a. Or the fly-eye lens 11 used in an embodiment of the present invention.
Apart from A and 11B, a fly-eye lens (hereinafter
The illumination light may be made uniform using an optical integrator such as another fly-eye lens.
At this time, another fly-eye lens is an optical member (that is, an input optical system) that varies the illumination light amount distribution near the light source side focal plane 11a of the fly-eye lenses 11A and 11B, for example, the polyhedral prism shown in FIG. It is desirable that the light source side be closer to 5 or the like. Alternatively, separate fly-eye lens groups may be separately provided on the reticle side of the fly-eye lenses 11A and 11B. In this way, by making the two illumination lights uniform with the two fly-eye lenses, further uniformity can be achieved.

In the above embodiment, the pyramid prism is used as the light beam splitting member. However, the present invention is not limited to this. For example, it may be a lens array in which a plurality of lenses are arranged, or may be divided using a polygon mirror.
Also in this case, the intensity of each light beam may be adjusted by moving the lens array or the polygon mirror in a plane perpendicular to the optical axis AX.

In the above description, at least a part of the light beam splitting member is moved to change the light beam splitting position of the illumination light beam (the relative position between the illumination light beam and the light beam splitting member). A parallel flat glass may be provided between the light splitting member 5 and the inclination of the parallel flat glass may be changed to change the position at which the illumination light is split.

Further, as disclosed in Japanese Patent Application Laid-Open No. 60-78454, a sensor with a pinhole or a two-dimensional CCD sensor is provided on a stage instead of the illuminance meter 21, and a four-dimensional sensor as shown in FIG. Irradiation unevenness in the image plane of illumination light by one fly-eye lens among one fly-eye lens may be measured and evaluated for each fly-eye lens.

If the plurality of light beams incident on the fly-eye lens 11 have an intensity difference that cannot be corrected by the movement of the prism 5a, the fly-eye lens 11 in FIG.
Absorbing filter (or wire mesh etc.) on the light source side of A, 11B
May be provided and used together with the movement of the prism 5a. For example, consider a case where the prism 5 divides the illumination light into four and each light beam enters four fly-eye lenses. Assuming that the centers of the four fly-eye lenses are at points Pζ, Pη, Pκ, and Pμ in FIG. 6D, Pζ and Pκ
The prism is moved so that the intensity of the illumination light from the fly-eye lens at the position is equal, and the filter is corrected so that the intensity of the illumination light from Pη and Pμ is equal.

Further, the intensity of a plurality of light beams may be positively varied according to the periodicity of the reticle pattern by using at least one of the prism 5 and the filter. This will be described with reference to FIG. FIG. 7A shows X,
FIG. 7B shows a reticle pattern in which two types of patterns, that is, a two-dimensional pattern in the two-dimensional Y direction and a pattern in a 45-degree direction with respect to the X and Y directions, are mixed. (Position of the fly-eye lens), and the positional relationship is the same as that shown in FIG. As an example of how to vary the intensity, the region 110 in FIG.
g, 110h, the intensity of the light beam is adjusted by the prism, and the intensity of the light beam from the regions 110i, 110j is reduced by the filter.

At this time, the exposure apparatus of the present embodiment is
In the case of having means for controlling the imaging characteristics of the projection lens (such as a method of controlling the pressure between the projection lens elements) as disclosed in Japanese Patent Application Publication No. May vary, causing an error in the control amount. In order to prevent this, a parameter for obtaining the control amount may be changed according to the light amount ratio between the light beams.

In the above embodiment, the illumination light is made to enter each of the divided fly-eye lens groups. However, the area illuminated in one large undivided fly-eye lens is light. The illumination light may be made to enter such that it becomes a discrete area decentered from the axis AX.

[0081]

As described above, according to the present invention, it is possible to realize a projection exposure apparatus having a higher resolution and a larger depth of focus than conventional ones while using a normal mask. Moreover, according to the present invention, it is only necessary to change the illumination system part and the main control system part of the projection exposure apparatus already operating at the semiconductor production site, and to use the projection optical system of the operating apparatus as it is. Higher resolution than before can be achieved. Further, even when the orientation characteristic or the position of the light source changes due to the lamp replacement or the laser replacement of the exposure apparatus, such a change can be compensated for without loss of light amount, and a stable exposure apparatus can be realized. .

[Brief description of the drawings]

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

FIG. 2 is a diagram schematically showing a configuration from a fly-eye lens to a projection optical system in a projection exposure apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating the arrangement of a fly-eye lens and the configuration of a movable member thereof in a projection exposure apparatus according to an embodiment of the present invention, as viewed from the optical axis direction.

FIG. 4 is a diagram showing an arrangement of a fly-eye lens and a configuration of a movable member thereof in a projection exposure apparatus according to an embodiment of the present invention, as viewed from a direction perpendicular to an optical axis.

FIG. 5 is a diagram showing another configuration of the input optical system.

FIGS. 6A and 6C are diagrams showing an example of a reticle pattern formed on a mask; FIGS. 6B and 6D are FIGS.
FIG. 6 is a diagram showing a position of a fly-eye lens on a Fourier transform plane of a reticle pattern, which is optimal for illuminating a pattern as shown in FIGS.

FIG. 7A is a diagram showing another example of a reticle pattern used in the projection exposure apparatus according to the embodiment of the present invention;
Is optimal for illuminating the pattern shown in FIG.
Diagram showing the position of the fly-eye lens and the illumination intensity on the Fourier transform plane of the reticle pattern

FIG. 8 illustrates the principle of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional projection exposure apparatus.

[Explanation of symbols]

 5a, 5b Polyhedral prism 6a, 6b Active member 9 Lens system 10 Absorbing filter 11A, 11B, 11C, 11D Fly-eye lens 12, 12A, 12B Light shield (spatial filter) 12c Fourier transform surface of reticle pattern 21 Illuminance meter 50 Main Control system 70A, 70B, 70C, 70D Support rod 71A, 71B, 71C, 71D Moving member 72A, 72B, 72C, 72D Fixed guide

Claims (45)

(57) [Claims] 1. A projection exposure apparatus comprising: an illumination optical system for irradiating illumination light from a light source onto a mask; and a projection optical system for projecting an image of a pattern of the mask onto a substrate. The light amount distribution of the illumination light on a predetermined surface that is substantially in a Fourier transform relationship with respect to the pattern of the mask is decentered from the optical axis of the illumination optical system, the distance to the optical axis is equal, and An illumination light generating unit configured to increase the intensity of the light flux emitted from the plurality of regions in a plurality of regions whose positions on the predetermined surface are set in accordance with the pattern, and to make the intensity of the light beams emitted from the plurality of regions substantially equal; The projection exposure apparatus includes a pair of prisms that are relatively movable along an optical axis of the illumination optical system. 2. The projection exposure apparatus according to claim 1, wherein an interval between the pair of prisms is adjusted according to a distance between an optical axis of the illumination optical system and the plurality of regions. 3. The apparatus according to claim 1, wherein an interval between the pair of prisms is adjusted to change a distance between an optical axis of the illumination optical system and the plurality of regions. Projection exposure equipment. 4. The distance between the pair of prisms is adjusted to move the plurality of regions on the predetermined surface in a radial direction about the optical axis of the illumination optical system. Item 3. The projection exposure apparatus according to item 1 or 2. 5. The projection exposure according to claim 1, wherein a distance between the pair of prisms is adjusted to change the light amount distribution according to a pattern to be transferred onto the substrate. apparatus. 6. The first prism, into which the illumination light is incident, of the pair of prisms has a convex exit surface, and the second prism, which emits the illumination light, has a concave entrance surface. The projection exposure apparatus according to any one of claims 1 to 5, wherein 7. The incident surface of the first prism and the second prism.
7. The projection exposure apparatus according to claim 6, wherein the exit surfaces of the prisms are planes substantially perpendicular to the optical axis of the illumination optical system. 8. The projection exposure apparatus according to claim 6, wherein the first prism is movable in a direction perpendicular to an optical axis of the illumination optical system. 9. The projection exposure apparatus according to claim 1, wherein each of the pair of prisms is a polyhedral prism. 10. The projection exposure apparatus according to claim 1, wherein the pair of prisms is disposed between the light source and an optical integrator in the illumination optical system. . 11. The projection exposure apparatus according to claim 10, wherein said illumination light generating means includes a lens system for converging illumination light emitted from said pair of prisms on an incident surface of said optical integrator. apparatus. 12. The projection exposure apparatus according to claim 1, wherein the pair of prisms is disposed substantially conjugate with the predetermined surface in the illumination optical system. 13. The distance between the plurality of regions and the optical axis of the illumination optical system is determined according to the fineness of a pattern to be transferred onto the substrate.
The projection exposure apparatus according to any one of the above. 14. When the pattern extends in the first and second directions, respectively, the plurality of regions have substantially equal first distances to the optical axis in the first direction and the light in the second direction. 14. The projection exposure apparatus according to claim 13, wherein the second distance from the axis is substantially equal. 15. The plurality of regions, wherein the first distance is determined according to the fineness of the pattern in the first direction, and the second distance is determined in accordance with the fineness of the pattern in the second direction. 15. The projection exposure apparatus according to claim 14, wherein: 16. When the pattern extends at least in a first direction, the plurality of regions are substantially parallel to the first direction and optical axes of the illumination optical system with respect to a second direction orthogonal to the first direction. The projection exposure apparatus according to any one of claims 1 to 13, wherein the projection exposure apparatus is arranged on a pair of first line segments separated by a distance according to a degree of fineness of the pattern in the second direction. . 17. When the pattern also extends in a second direction orthogonal to the first direction, the plurality of regions are substantially parallel to the second direction and light of the illumination optical system with respect to the first direction. 17. A pair of second line segments separated from an axis by a distance corresponding to a degree of fineness of the pattern in the first direction, and arranged on each of the pair of first line segments. 3. The projection exposure apparatus according to claim 1. 18. The projection exposure apparatus according to claim 17, wherein the plurality of regions are arranged on an intersection between the pair of first line segments and the pair of second line segments. 19. A diffracted light beam of different orders generated from the pattern by irradiation of a light beam emitted from each of the regions passes through a position on the pupil plane of the projection optical system which is substantially equidistant from an optical axis. 19. The projection exposure apparatus according to claim 1, wherein the position of each of the regions is determined so as to perform the operation. 20. The projection exposure apparatus according to claim 19, wherein the two diffracted lights are one of ± n order diffracted lights and a 0 order diffracted light. 21. An angle of incidence of a light beam emitted from each of the regions on the mask, and ± n generated from the pattern.
The diffraction angle of the diffracted light theta, the number of mask-side numerical aperture of the projection optical system when the NA _R, sin in one of the ± n order diffracted light
3. The resolution limit of the projection optical system when the relationship (θ-ψ) = NA _R is satisfied.
0. The projection exposure apparatus according to claim 1. 22. The one-dimensional diffracted light that satisfies the above relationship is substantially symmetric with respect to the optical axis of the projection optical system with respect to the zero-order diffracted light generated from the pattern.
2. The projection exposure apparatus according to claim 1. 23. Assuming that the wavelength of the illumination light is λ and the pitch of the pattern is P, an incident angle 光 of the light flux emitted from each of the regions to the mask satisfies a relationship of sinψ = λ / 2P. 23. The projection exposure apparatus according to claim 1, wherein a position of each of the regions is determined. 24. The incident angle to the mask of the light flux emitted from each region [psi, the wavelength of the illumination light lambda, the number of mask-side numerical aperture of the projection optical system as NA _R, on the substrate The minimum pitch of the transferable pattern is λ / (NA _R +
The projection exposure apparatus according to any one of claims 1 to 23, wherein sinψ). 25. The pattern has a periodic structure in which the pitch is smaller than λ / NA _R, where λ is the wavelength of the illumination light and NA _R is the numerical aperture of the projection optical system on the mask side. The projection exposure apparatus according to claim 1. 26. When the pattern extends in the first and second directions, respectively, a zero-order diffracted light generated from the pattern by irradiation of a light beam emitted from each of the regions, and the first direction centering on the zero-order diffracted light. One of the high-order diffracted lights distributed in the
26. The position of each of the regions is determined such that one of the higher-order diffracted lights distributed in the direction is distributed at substantially the same distance from the optical axis on the pupil plane of the projection optical system.
The projection exposure apparatus according to any one of the above. 27. The projection exposure apparatus according to claim 26, wherein the one high-order diffracted light distributed in the first and second directions has the same order. 28. The apparatus according to claim 1, wherein the plurality of regions are arranged substantially symmetrically with respect to an optical axis of the illumination optical system on the predetermined surface. Projection exposure equipment. 29. A ratio of a numerical aperture of a light beam emitted from each of the areas to a mask-side numerical aperture of the projection optical system is set to 0.1 to
29. The method according to claim 1, wherein the value is set to about 0.3.
The projection exposure apparatus according to any one of the above. 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 of the mask is provided in the illumination optical system. The light amount distribution of the illumination light on a predetermined surface that is substantially in a Fourier transform relationship with respect to the optical axis of the illumination optical system is decentered, the distance from the optical axis is equal, and according to the pattern The position on the predetermined surface is increased in a plurality of regions, and the intensities of the light beams emitted from the plurality of regions are made substantially equal, and the light beams can be relatively moved along the optical axis of the illumination optical system. A projection exposure method, wherein a distance between an optical axis of the illumination optical system and the plurality of regions is set using a pair of prisms. 31. The projection exposure method according to claim 30, wherein a distance between the optical axis of the illumination optical system and the plurality of regions is changed by adjusting a distance between the pair of prisms. 32. An apparatus according to claim 30, wherein an interval between said pair of prisms is adjusted to change said light amount distribution in accordance with a pattern to be transferred onto said substrate.
2. The projection exposure method according to 1. 33. A distance between the plurality of regions and an optical axis of the illumination optical system is determined according to a fineness of a pattern to be transferred onto the substrate.
3. The projection exposure method according to any one of 2. 34. When the pattern extends in the first and second directions, respectively, the plurality of regions have substantially the same first distance from the optical axis in the first direction and the light in the second direction. 34. The projection exposure method according to claim 33, wherein the second distance from the axis is substantially equal. 35. The plurality of regions, wherein the first distance is determined according to the fineness of the pattern in the first direction, and the second distance is determined in accordance with the fineness of the pattern in the second direction. 35. The projection exposure method according to claim 34, wherein: 36. When the pattern extends in at least a first direction, the plurality of regions are substantially parallel to the first direction and the optical axis of the illumination optical system with respect to a second direction orthogonal to the first direction. The projection exposure method according to any one of claims 30 to 33, wherein the projection exposure method is arranged on a pair of first line segments separated by a distance according to a degree of fineness of the pattern in the second direction. . 37. When the pattern also extends in a second direction orthogonal to the first direction, the plurality of regions are substantially parallel to the second direction and the light of the illumination optical system with respect to the first direction. 37. A pair of second line segments separated from an axis by a distance according to the fineness of the pattern in the first direction, and the pair of first line segments are arranged on the respective line segments. 3. The projection exposure method according to 1. 38. The projection exposure method according to claim 37, wherein the plurality of regions are arranged on an intersection between the pair of first line segments and the pair of second line segments. 39. An angle of incidence of a light beam emitted from each of the regions on the mask, and ± n generated from the pattern.
The diffraction angle of the diffracted light theta, the number of mask-side numerical aperture of the projection optical system when the NA _R, sin in one of the ± n order diffracted light
31. The resolution limit of the projection optical system when the relationship (θ-ψ) = NA _R is satisfied.
39. The projection exposure method according to any one of items 38. 40. When the wavelength of the illumination light is λ and the pitch of the pattern is P, the incident angle 入射 of the light flux emitted from each of the regions to the mask satisfies the relationship of sinψ = λ / 2P. 40. The projection exposure method according to claim 30, wherein a position of each of the regions is determined. 41. The incident angle to the mask of the light flux emitted from each region [psi, the wavelength of the illumination light lambda, the number of mask-side numerical aperture of the projection optical system as NA _R, on the substrate The minimum pitch of the transferable pattern is λ / (NA _R +
The projection exposure method according to any one of claims 30 to 40, wherein sin で あ). 42. The pattern has a periodic structure in which the pitch is smaller than λ / NA _R, where λ is the wavelength of the illumination light and NA _R is the numerical aperture of the projection optical system on the mask side. The projection exposure method according to any one of claims 30 to 41. 43. When the pattern extends in the first and second directions, respectively, a zero-order diffracted light generated from the pattern by irradiating a light beam emitted from each of the regions, and the first direction centering on the zero-order diffracted light. One of the high-order diffracted lights distributed in the
The position of each of the regions is determined such that one of the higher-order diffracted lights distributed in the direction is distributed at substantially the same distance from the optical axis on a pupil plane of the projection optical system.
3. The projection exposure method according to any one of 2. 44. The apparatus according to claim 30, wherein the plurality of regions are arranged substantially symmetrically with respect to an optical axis of the illumination optical system on the predetermined surface. Projection exposure method. 45. A ratio of a numerical aperture of a light beam emitted from each of the regions to a mask-side numerical aperture of the projection optical system is set to 0.1 to 45.
5. The method according to claim 4, wherein the distance is set to about 0.3.
5. The projection exposure method according to claim 4.