JP3102087B2 - Projection exposure apparatus and method, and circuit element forming 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 type exposure apparatus, and more particularly to a focus associated with switching of an illumination system of a projection type exposure apparatus used for transferring a circuit pattern of a semiconductor integrated device or a pattern of a liquid crystal element. This relates to adjustment and focus adjustment accompanying switching of a mask to be used.

[0002]

2. Description of the Related Art Forming a circuit pattern of a semiconductor or the like requires a step generally called a photolithographic technique.
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 mask pattern. In a projection type exposure apparatus, a circuit pattern to be transferred drawn on a mask is projected and imaged on a sample substrate (wafer) via a projection optical system.

In a conventional projection exposure apparatus, the distribution of the amount of illumination light flux incident on a surface corresponding to the Fourier transform of a mask or a surface in the vicinity thereof is substantially circular (or rectangular) around the optical axis of the illumination optical system. (Normal illumination). When the pattern pitch becomes finer, the diffraction angle of the light beam passing through the mask increases, and when the diffraction angle becomes larger than the reticle-side numerical aperture (NA _R ) of the projection optical system, ±
The first-order diffracted light cannot pass through the projection optical system.

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

Further, the numerical aperture of the projection optical system is already close to the theoretical limit at present, and it is almost impossible to further increase the numerical aperture. Further, even if the aperture can be made larger than the current state, the depth of focus represented by ± λ / 2NA ² decreases sharply with an increase in the numerical aperture, and the depth of focus required for actual use is further reduced. The problem of becoming more pronounced.

In recent years, Japanese Patent Application Laid-Open No. 2-50417 discloses that an illumination optical system and a projection optical system are provided with an aperture stop concentric with an optical axis to restrict the angle of incidence of illumination light on a mask and to provide a mask pattern. It is disclosed that the aperture diameter is adjusted accordingly to secure the depth of focus while maintaining the contrast of the projected image on the data substrate. Further, it has been proposed to provide an illumination system with a ring-shaped aperture stop in which a ring-shaped light transmitting portion is formed concentrically with the optical axis as a center, thereby increasing the depth of focus (zonal illumination).

Further, by causing the illumination light to enter the mask at a predetermined incident angle, the 0th-order light and the 1st-order diffracted light that pass through a position decentered from the optical axis on the pupil plane in the projection optical system interfere with each other to achieve resolution. There has been proposed a technique for improving the brightness (inclined lighting). On the other hand, of the transparent portions of the circuit pattern of the mask,
A phase shift mask that shifts the phase of transmitted light from a specific portion by π from the phase of transparent light from another transmitted portion has been proposed in Japanese Patent Publication No. Sho 62-50811.

[0008]

However, due to the change of the illumination light shape and the introduction of the phase shift mask as described above, the position and shape of the light beam passing through the projection optical system in the pupil plane are variously changed. This will be described more specifically. If the numerical aperture of the projection lens is NA and the numerical aperture of the illumination system is NAi,
The σ value which is one parameter of the illumination system is σ = NAi / N
Defined by A. This σ value is conventionally about 0.5, and when a conventional illumination method (normal illumination) is performed or when a normal mask is used, the diffracted light from the mask causes the optical axis of the projection optical system to fall within the pupil plane. Including it, it spread throughout the aperture (pupil plane).
On the other hand, for example, in a phase shift mask, the σ value is set to 0.
Used as about 3.

Further, since the light beam including the optical axis disappears in the pupil plane due to the principle of the phase shift, the light beam passes through only a part of the peripheral area in the pupil plane of the projection optical system. Further, even when the above-described annular illumination or oblique illumination is performed, there is no light beam including the optical axis in the pupil plane, as in the case of the phase shift mask, and the light beam passes only in a peripheral region in the pupil plane. As described above, when the σ value changes or the state of light flux passing through the pupil plane changes, the projection optical system is affected by minute spherical aberration remaining in the projection optical system and minute light absorption of the projection optical system. Slightly fluctuates in the focal position of.

The present invention has been made in view of such a problem, and is irrespective of changes in the illumination light state (changes in the position, shape, and numerical aperture of a light beam passing through a pupil plane) and the introduction of a phase shift mask. The purpose is to always perform exposure at the best focus position.

[0011]

According to the present invention, there is provided an illumination optical system for irradiating illumination light from a light source (1) onto a mask (12) having a fine pattern, and a mask pattern image. A projection optical system (14) for projecting and exposing on a substrate (16), a stage (19) holding the substrate and movable in the optical axis direction of the projection optical system, and a predetermined connection of the projection optical system in the optical axis direction. Detects the relative position deviation between the image plane and the substrate,
Focus detection means (A) for outputting a detection signal corresponding to the deviation
F, 24, 25) and control means (32, 33) for controlling the movement of the stage based on the detection signal, the numerical aperture of the projection optical system and the numerical aperture of the illumination optical system Input means (34, 35) for inputting information on at least one of a shape of a light beam passing through a Fourier transform surface of the mask in the projection optical system and a position of the light beam passing through the Fourier transform surface; Setting means (6, 15a, 6) for setting predetermined exposure conditions based on information from
0, 40, 41, 5, 12b); switching means (TA, 37, 4) for switching the exposure conditions set in the setting means.
Adjustment means for adding an offset to one of the focus detection means and the control means by a value corresponding to a change in the position in the optical axis direction of the predetermined image plane which is changed by the switching by the switching means. (33, 32).

[0012]

According to the present invention, exposure at the best focus position can always be realized even if the focus position fluctuates due to the change of the illumination light shape or the exchange of the normal mask and the phase shift mask.

[0013]

FIG. 1 shows the configuration of a projection type exposure apparatus according to an embodiment of the present invention. The illumination light flux generated from the mercury lamp 1 is focused on the second focal point f ₀ of the elliptical mirror 2,
The light enters a fly-eye lens 5 via a mirror 3 and a lens system 4 such as a relay system. Fly-eye lens 5 is reticle 1
2 to make the intensity distribution of the illumination light irradiated on the surface 2 uniform. Reticle-side focal plane 5 of fly-eye lens 5
An aperture stop 6 is provided near a. The aperture stop 6 is provided with an opening 6 a for limiting illumination light to a circular area (or a rectangular area) centered on the optical axis AX.
The numerical aperture of the illumination system is determined by the magnitude of a, which determines the σ value.

A plurality of aperture stops 6 having different sizes of apertures are provided in the rotary plate TA, and the size of the apertures can be changed by driving the rotary plate TA by the driving unit 36. In addition, another aperture stop is provided in the rotary plate TA,
For example, an aperture stop 6-C in which a ring-shaped transparent portion is provided concentrically around the optical axis is provided, and the shape of the opening can be arbitrarily selected by driving the rotary plate TA. When the size of the opening is changed, a variable aperture stop may be provided to change the size of the opening. On the other hand, the reticle-side focal plane 5b of the fly-eye lens 5
Is the Fourier transform plane (pupil conjugate plane) of the reticle pattern 13
Are arranged in an in-plane direction perpendicular to the optical axis AX so as to substantially coincide with the optical axis AX. The light source side focal plane 5a of the fly-eye lens
And the reticle-side focal plane 5b naturally have a Fourier transform relationship. Therefore, in the case of the example of FIG. 1, the reticle-side focal plane 5 b of the fly-eye lens, that is, the exit surface of the fly-eye lens 5 has an imaging relationship (conjugate) with the reticle pattern 13.

Here, the method of changing the σ value is not limited to the aperture stop. As shown in FIG. 2, an afocal variable power optical system 60 is arranged between the parallel optical paths of the input lens 3 and the fly-eye lens 4. The secondary light source image formed on the exit side surface 5b of the fly-eye lens 5 may be efficiently changed by the zooming by the afocal zooming optical system 60. This adjustment is performed by the drive unit 61.

FIG. 2 shows the fly-eye lens 5 shown in FIG.
In the figure, the optical configuration on the light source side is shown. In the drawing, the afocal variable power optical system 60 includes a first positive lens group 60a, a second negative lens group 60b, and a positive first lens group 60b. And one lens group 60c. Then, as shown in FIGS. 2A and 2B, each lens group (60a-6
Zooming is achieved by moving 0c), and the size of the secondary light source formed on the exit side of the fly-eye lens can be changed without blocking light. In addition, even when the magnification of the afocal variable power optical system 60 is changed, the incident side surface 5a of the fly-eye lens is provided substantially conjugate with the opening 2a of the elliptical mirror with respect to the input lens 4 and the afocal variable power optical system 60. . Thereby, while maintaining the double conjugate relationship between the object plane and the pupil plane (Fourier plane), the
The value can be variable.

Now, returning to FIG. 1, the light beam L 1 emitted from the opening 6 a is guided to the reticle blind 8 by the relay lens 7. The reticle blind 8 is provided on a surface substantially conjugate with the reticle pattern 13, is a field stop for illuminating only a specific area on the reticle 12, and has a variable size by a drive system (not shown). The light beam L1 that has passed through the reticle blind 8 illuminates the reticle 12 via the relay lens 9, the mirror 10, and the condenser lens 11. The luminous flux L1 is the reticle pattern 13
The diffracted light generated from the
It is focused and imaged on it. The drive unit 37 is provided with the NA diaphragm 15
a is driven to change the size of the pupil plane 15 of the projection optical system, and the NA of the projection optical system 14 can be changed to a desired value.

The wafer 16 is vacuum-sucked on a wafer chuck 17, and the wafer chuck 17 is provided on a Z stage 19 that can be moved in a Z direction (optical axis direction) by a motor 18. Further, the Z stage 19 is provided on an XY stage 21 that can be moved two-dimensionally by a motor 20,
At the end of the Z stage, a reflecting mirror 23 for reflecting a laser beam from the laser interferometer 22 is provided. The position of the XY stage 21 is determined by the laser
It is always detected with a resolution of 01 μm.

On the XY stage 21, a reference member (glass substrate) 24 provided with a fiducial mark used for detecting a focal position (imaging position) is set so as to substantially coincide with the surface position of the wafer 16. Is provided. Although not shown in this embodiment, two sets of light-transmitting slit patterns (bar patterns) are formed in the X and Y directions as a fiducial mark. Further, a photoelectric detector 25 such as a PIN photodiode is disposed inside the Z stage 19 near the reference member 24. In this embodiment, a focus detection measurement pattern (for example, a light-transmitting cross The illumination light passing through the slit is received through the slit pattern. FIG. 1 shows a state where the projected image of the circuit pattern is formed not on the wafer 16 but on the reference member 24. In this embodiment, while driving the Z stage 19,
By detecting the amount of light that passes through the reference member 24 and reaches the photoelectric detector 25, the image forming position (focal position) of the focus position measuring pattern by the projection optical system 14 is detected.
The method of focus detection is disclosed in Japanese Patent Application Laid-Open No. 59-094032.

The projection exposure apparatus shown in FIG. 1 is provided with a gap sensor AF for detecting the distance between the projection optical system 14 and the surface of the wafer 16. The light beam from the light projector 26 is obliquely incident on the optical axis AX toward a predetermined image forming surface of the projection optical system via the mirror 27, and the detector 31 reflects the reflected light from the wafer 16 (reference member 24) to the mirror 28. , And receives light through the parallel flat glass 29 to output a photoelectric signal. The detector 31 is a one-dimensional position detector such as a CCD, and detects a change in the position of the wafer 16 in the Z direction as a position change on the position detector. The focus controller 32 outputs a drive signal to the motor 18 to drive the Z stage 19 so that the reflected light is received at the center of the position detector, for example. With this gap sensor, the surface of the wafer 16 can always be made to coincide with a predetermined imaging plane.

When the gap sensor AF is provided with an offset, the angle of the parallel flat glass
By changing it to 0, the position of the reflected light incident on the position detector may be shifted from the center, or the output from the position detector may have an offset. Note that the configuration of the gap sensor AF is not limited to this, and a synchronous detection method as disclosed in Japanese Patent Application Laid-Open No. S60-168112 may be used. Alternatively, a gap sensor that irradiates slit-like light covering the entire image feed of the projection optical system and detects reflected light with each of the detectors divided into a plurality of regions may be used.

FIG. 1 shows a main control system 33 for integrally controlling the apparatus and names formed beside the reticle pattern 13 while the reticle 12 is being conveyed by the reticle conveyance system 38 directly above the projection optical system 14. Barcode BC representing
And a keyboard 35 for inputting commands and data from an operator. In the main control system 33, the names of a plurality of reticles to be handled by the stepper and the operation parameters of the stepper corresponding to each name are registered in advance. When the barcode reader 34 reads the reticle barcode BC, the main control system 33 reads the aperture stop 6 registered in advance as one of the operation parameters corresponding to the name.
Information such as the aperture stop of the projection optical system 14 and the like,
Output to the drive unit 37. In this manner, adjustment is made so that the illumination condition such as the optimal illumination light shape (normal or annular zone) and the optimal σ value, and the optimal NA of the projection optical system are obtained.

The main control system 33 has a gap sensor AF according to the illumination light shape, σ value, NA, etc. as one of the parameters.
The focus offset value that gives an offset to the reticle is stored in correspondence with the reticle name (barcode information).
Then, an offset value corresponding to a change in the position of the predetermined image plane in the optical axis direction, which is changed by at least one of the switching of the illumination condition such as the σ value and the switching of the NA, is selected as a parameter.

The focus offset value is obtained according to the illumination conditions such as the σ value, the NA, etc., and serves as information for coping with a change in a predetermined image plane. This offset value may be recorded on the reticle as barcode information. In addition, trial printing or the like is performed in advance to determine the best image forming plane under each illumination condition, and the bar code information is recorded on the reticle, or the main control system 33 is associated with the reticle name (bar code information). May be recorded in the memory.

The above operation can also be executed by the operator directly inputting commands and data from the keyboard 35 to the main control system 33. Further, each time at least one of the σ value, NA, and each illumination light shape is selected / set, the best imaging plane may be obtained by using the aforementioned reference member 24 and stored in the main control system 33.

The position of the light beam passing through the pupil plane 15 of the projection optical system differs depending on the shape of the aperture stop selected by the reticle. This is shown in FIGS. 3, 4, and 5, and FIG.
4A, FIG. 4A, and FIG. 5A, the solid line indicates the zero-order light, the dashed-dotted line indicates the -1st-order diffracted light, and the dotted line indicates the + 1st-order diffracted light. 9, 11, mirror 1
1 is simply shown as a mirror 11. FIG.
FIG. 3A shows a basic optical path when the size of the opening 6a is set to a value of about 0.5 (aperture stop 6-A), and FIG. 3B shows the basic optical path. 0 in the pupil plane 15 in the case of
Next, the spread of ± 1 order light is shown. FIGS. 4A and 4B show the basic optical path and the 0th order in the pupil plane 15 when the size of the opening 6a is set so that the σ value is about 0.3 (aperture stop 6-B). , ± 1 order light spread. FIGS. 5A and 5B show the basic optical path and pupil plane 1 when the aperture stop 6 is replaced with an annular stop 6-C having an annular transmission portion.
The 0th order and ± 1st order light spread of 5 are shown. FIG.
(B), as shown in FIGS. 3 (b) and 4 (b), the pupil plane 1
The position of the light beam passing through 5 greatly differs depending on the shape of the opening, and the spherical aberration and the light absorption amount also differ.

In the annular illumination shown in FIG. 5, if there is no light beam including the optical axis AX in the pupil plane 15 and there is spherical aberration, the position of the best image plane in the Z direction changes. 3 and 4, the position (or shape) of the light beam passing through the pupil plane 15 is different and the size of the aperture stop is different, so that the amount of absorbed light and the spherical aberration are different, and the position of the best imaging plane is different. different. Further, the lens in the projection optical system is heated by the absorption of light, causing a change in refractive index and expansion. The focal position of the projection optical system may change due to the change of the lens.

For this reason, it is necessary to add an offset to the gap sensor AF for each illumination light shape depending on the amount of absorbed light and the residual spherical aberration. Next, a typical operation of this embodiment will be described. The barcode BC provided on the reticle 12 is read by a barcode reader 34, and optimal illumination conditions (illumination light shape, σ
Value), NA. Here, it is assumed that the drive unit 36 selects the aperture stop 6-A that can obtain the illumination condition as shown in FIG. 3 based on the information of the barcode BC.

Next, the reticle is exchanged by the reticle transport system 38. The barcode BC provided on the reticle after the replacement is read by the barcode reader 34, and the optimum illumination condition is selected. Here, it is assumed that the annular stop 6-C as shown in FIG. 5 is selected. Bar code information
The illumination condition such as the value and the information of NA are recorded, and a corresponding focus offset value is obtained from this information and the information stored in the main control system 33 in advance, and the electrical and optical offset amount is determined by the gap. Add to sensor AF. Thereby, even when the illumination condition such as the σ value and the NA change,
Exposure can be performed while the surface of the wafer 16 always coincides with a predetermined imaging plane.

The Z stage 1 has an amount corresponding to the focal difference.
9 so that the reflected light from that position is incident on the center of the position detector 31.
May be driven to perform focus calibration, or the focus position may be detected using the reference member 24 each time the reticle is replaced, and the reference member 24
Alternatively, the Z stage 19 may be moved so that the surface is positioned, and focus calibration may be performed at this focal position.

Further, an offset may be added to the position of the reticle or the Z stage 19 in the optical axis direction. Here, in the case where the projection exposure apparatus according to the present embodiment includes a control system or the like for controlling the pressure between a plurality of lens elements, an imaging variation occurs due to accumulation of the irradiation amount in the projection optical system. The tracking control of the glass is performed so as to sequentially offset the focus position. Therefore, as in the present invention, the offset with respect to the change of the imaging plane position due to at least one change of the illumination condition such as the σ value and the NA may be added as a correction amount (constant value) to the tracking control signal. A control system for controlling the pressure between a plurality of lens elements and tracking control are disclosed in Japanese Patent Application Laid-Open No. 63-58349.

The projection type exposure apparatus according to this embodiment has a control system for controlling the pressure between a plurality of lens elements of a projection optical system as disclosed in Japanese Patent Application Laid-Open No. 63-58349. Then, a second embodiment of the present invention will be described. The illumination conditions are not limited to those described above, but may be tilted illumination in which the 0th-order light and the ± 1st-order diffracted lights passing on the pupil plane 15 pass through the eccentric positions separated from the optical axis AX. In particular, although not yet known, the applicant has filed an application, and divides the luminous flux from the light source into a plurality of illumination lights (for example, two or four), and performs the inclined illumination with each of the illumination lights. Exposure apparatuses have been proposed.
(Hereinafter, the oblique illumination performed with a plurality of light beams in this specification is referred to as “plural oblique incidence illumination”.) 0 on the pupil plane 15
The focal position also varies depending on the position where each of the secondary light and the ± first-order diffracted light passes and the number of illumination light.

The focus variation in the case of oblique illumination, particularly in the case of multiple oblique incidence illumination will be described below. FIG. 6 shows a portion corresponding to the portion from the lens 4 to the reticle 12 in FIG. 1. The portion from the lens 4 to the light source 1, the portion from the reticle 12 to the wafer 16, the stage, the main control system, the drive system, etc. The same applies to the lenses 7, 9, 11,
The mirror 10 is schematically illustrated as a lens 11. The same members as those in FIG. 1 are denoted by the same reference numerals.

The illumination light from the light source 1 enters the light splitting members 40 and 41 via the lens 4. Here, the light splitting member is
A first polyhedral prism 40 having a V-shaped concave portion and a second polyhedral prism 41 having a V-shaped convex portion were used. Due to the refraction of these two prisms, the illumination light beam is split into two light beams. Each light beam is a separate fly-eye lens 5
A, 5B. Here, the fly-eye lens group 5
A and 5B are two, but this quantity may be arbitrary. The light dividing member may be divided into any number according to the number of fly-eye lens groups. For example, if the number of fly-eye lens groups is four, each of the light splitting members 40 and 41 may be a pyramid-shaped polygonal prism.

The light beams L2 and L3 emitted from the fly-eye lens groups 5A and 5B enter the reticle 12 via the lens 11 at a predetermined angle with respect to the optical axis AX. The reticle-side focal plane 5b of each of the fly-eye lens groups 5A and 5B is provided at a position substantially coincident with the Fourier transform plane 50 for the reticle pattern 13. Fly-eye lens group 5
A spatial filter 43 having openings corresponding to the sizes of the fly-eye lens groups 5A and 5B is provided in the vicinity of the reticle-side focal plane 5b of A and 5B to block unnecessary light beams. I have.

The light splitting member is not limited to the prism, but is a diffraction grating pattern, a mirror, an optical fiber, and a spatial filter having an opening at a position decentered from the optical axis (corresponding to the aperture stop of the first embodiment). May be. The means for forming the plurality of illumination lights is not limited to the light splitting member, and a movable mirror or the like that concentrates the light flux on each of the fly-eye lens groups in a time-division manner may be used.

The holding member 42 includes a fly-eye lens group 5
A, 5B center (in other words, fly-eye lens group 5
A and 5B are set at discrete positions decentered with respect to the optical axis AX by an amount determined according to the periodicity of the reticle pattern. The fly-eye lens groups 5A and 5B are integrally held. Further, the movable member 44 (turret plate) and the holding member 42 together with the optical axis AX of the plurality of fly-eye lens groups are changed according to the difference in the periodicity of the reticle pattern 13.
A plurality of holding members (not shown) for holding the eccentric states with respect to each other are fixed integrally. By driving the movable member 44 by the driving member 48, each of the plurality of holding members can be exchanged. It can be arranged in the optical path of the illumination optical system.

Next, the structure of the movable member 44 for replacing the holding member will be described with reference to FIG. FIG. 7 is a diagram showing a specific configuration of the movable member, and here, four holding members 42,
45, 46 and 47 are arranged on a movable member (turret plate) 44 rotatable about a rotation shaft 44a at intervals of about 90 °. Illumination light beams L2 and L3 are incident on the fly-eye lens groups 5A and 5B, respectively, and the holding member 42 is arranged in the illumination optical system. At this time, the holding member 42 is arranged in the illumination optical system such that the center thereof substantially coincides with the optical axis AX. Each of the plurality of fly-eye lens groups 5A and 5B has an optical axis A of the illumination optical system whose center is determined by an amount determined according to the periodicity of the reticle pattern.
The holding member 42 is integrally held by the holding member 42 so as to be set at discrete positions eccentric with respect to X. Here, the holding members 42 are arranged substantially symmetrically with respect to the center (optical axis AX) of the holding member 42.

Now, the four holding members 42, 45, 46,
Each of the 47 moves the plurality of fly-eye lens groups in an eccentric state with respect to the optical axis AX (the center of the holding member) in accordance with the difference in the periodicity of the reticle pattern 13 (that is, positions in a plane substantially perpendicular to the optical axis AX). ) Are kept different from each other. Each of the holding members 42 and 45 has two fly-eye lens groups (5A and 5B) and (45A and 45B),
When these fly-eye lens groups are arranged in the illumination optical system, they are fixed so that their arrangement directions are substantially orthogonal to each other. The holding member 46 has four fly-eye lens groups 46A, 46B, 46C, and 46D at their centers 46cA.
(Optical axis AX) It is arranged and fixed at substantially the same distance from the optical axis AX. The holding member 47 is fixed such that the center of one fly-eye lens 47A substantially coincides with the center of the holding member, and is used when performing exposure in an illumination state as in the first embodiment. still,
When the spatial filter 43 is provided in the holding members 4, 45, 46, and 47, it is assumed that the spatial filter 43 is integrally held by the holding member together with the fly-eye lens group.

As described above, the turret plate 44 is rotated by the drive element 48 including a motor and gears according to the information of the reticle bar code BC, so that each of the four holding members 42, 45, 46, 47 can be replaced. A desired holding member according to the periodicity (pitch, arrangement direction, etc.) of the reticle pattern can be arranged in the illumination optical system. Further, by adjusting the distance between the prism 40 and the prism 41 by the driving member 48, the position of the illumination light beam on the Fourier transform surface 50 changes, and the illumination light beam is adjusted to each of the fly-eye lens groups having different eccentric states. Can be incident. Further, the fly-eye lens group and the light splitting member may be integrally held, and may be integrally replaced.

Further, as described above, the reticle bar code BC
According to this information, it is selected whether to perform exposure (normal illumination) as in the first embodiment or to perform multiple oblique incidence illumination, and to perform exposure for normal illumination, select the holding member 47 and perform multiple oblique incidence illumination. When lighting is performed, any one of the holding members 42, 45, and 46 may be selected. When performing the conventional exposure, the holding member 47 is selected, and the light beam splitting member is replaced with a predetermined optical system. When the lens 4 can concentrate the illumination light on the fly-eye lens group, it is only necessary to retract the light beam splitting member from the optical path.

In FIG. 6, the spatial filter 43 is arranged behind the holding member 42 (on the reticle side). No need to provide.
At this time, the turret plate 44 may be a transmission part or a light shielding part. Further, the number of holding members to be fixed to the turret plate 44 and the eccentric state (position) of the plurality of fly-eye lens groups are not limited to those shown in FIG. It may be set arbitrarily according to. 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. The holding members (the fly-eye lens groups 5A and 5B) may be configured to be rotatable about the optical axis AX.
At this time, particularly when an optical fiber is used as the light beam dividing member, the exit end of the fly-eye lens group is also configured to move with the movement of the fly-eye lens group. For example, the exit end and the fly-eye lens group are integrated. It should be fixed. 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. Although the fly-eye lens is usually rectangular, it is preferable that the four sides are set so as not to rotate with the four sides of the reticle.

The diameter per opening of the spatial filter 43 (or the area of the exit end of each fly-eye lens group) is
The numerical aperture of the illumination light beam transmitted through the opening to the reticle 12 and the reticle-side numerical aperture (NA _R ) of the projection optical system 14
Is desirably set so that the so-called σ value is about 0.1 to 0.3. If the σ value is smaller than 0.1, the pattern fidelity of the transferred image is degraded, and if it is larger than 0.3, the effect of improving the resolution and increasing the depth of focus is weakened.

In order to satisfy the condition of the σ value (approximately 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 5A and 5B is large. By the way, (the size in the in-plane direction perpendicular to the optical axis) may be determined according to the illumination light flux (emission light flux). Also,
Reticle-side focal plane 5 of each fly-eye lens group 5A, 5B
b, a variable aperture stop (spatial filter 43)
And the σ value may be changed by changing the numerical aperture of the light beam from each fly-eye lens group. At the same time, the NA as the projection system can be made variable by a variable aperture stop (NA limiting stop) 15a provided near the pupil (entrance pupil or exit pupil) 15 in the projection optical system 14. Further, the σ value may be optimized by using the lens system 4 as a zoom lens system.

FIG. 8 shows the state of the reticle 12 and the wafer 16.
FIG. 3 is a diagram schematically showing the basic optical path up to this point, and the state of incidence of a light beam L2 on a reticle and image formation on a wafer 16 will be described with reference to FIG. The circuit pattern 13 drawn on the reticle (mask) generally includes many periodic patterns. One 0-order diffracted light component D ₀ and ± 1-order diffracted light component D _P from the reticle pattern 13 the illumination light is irradiated from the fly's eye lens 5A, the D _m and more diffracted light components of higher order, the fine patterns Occurs in the direction according to the degree.

At this time, the illumination light beam (principal ray) is tilted.
Incident on the reticle 12 at an angle.
The diffracted light component also has a tilt (angle
(Delay) from the reticle pattern 13.
The illumination light L2 in FIG.
Illumination light L4 is incident on the reticle 12
And is inclined by ン with respect to the optical axis AX.
0th order diffracted light D traveling in the direction₀, Θ for the 0th order diffracted light_PIs
Inclined + 1st order diffracted light D_P, And zero-order diffracted light D ₀Against
And θ_m-1st order diffracted light D_mOccurs. I
However, the illumination light L2 is a telecentric projection on both sides.
Retick tilted by an angle に 対 し て with respect to the optical axis AX of the optical system 14
0th order diffracted light D₀Also projection
Travels in a direction inclined by an angle に 対 し て with respect to the optical axis AX of the optical system
I do.

Therefore, the + 1st-order light D _P travels in the direction of θ _P + に 対 し て with respect to the optical axis AX, and the −1st-order diffracted light D _m becomes the optical axis AX.
Proceeds in the direction of θ _m −ψ. At this time, the diffraction angle θ
_P, theta _m respectively _{sin (θ P + ψ) -} sinψ = λ / P (1) is _{sin (θ m -ψ) + sinψ} = λ / P (2).

[0048] Here, + 1-order diffracted light D _P, -1 both-order diffracted light D _m is assumed to transmit pupil 15 of the projection optical system 14. When the diffraction angle increases with the miniaturization of the reticle pattern 13, the reticle pattern 13 first advances in the direction of the angle θ _P + ψ.
1-order diffracted light D _P can not be transmitted through the pupil 15 of the projection optical system 14. That is, the relationship becomes sin (θ _P + ψ)> NA _R. But since the illumination light L2 is incident is inclined with respect to the optical axis AX, -1-order diffracted light D _m at a diffraction angle in this case is possible it enters the projection optical system 14. That is, s
in (θ _m −ψ) <NA _R

Accordingly, the zero-order diffracted light D ₀ is placed on the wafer 16.
If -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 13. When the reticle pattern 13 has a line and space ratio of 1: 1, the image of the reticle pattern 13 is formed on a resist applied on the wafer 16 with a contrast of about 90%. Patterning becomes possible.

The resolution limit at this time is when sin (θ _m -ψ) = NA _R (3), and therefore, NA _R + sinψ = λ / PP = λ / (NA _R + sinψ) (4) Is the pitch on the reticle side of the minimum pattern that can be transferred.

As an example, assuming that sinψ is set to 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 ( 5)

On the other hand, the distribution of illumination light on the Fourier transform surface 50 for the reticle 12 in the illumination system is
In the case of the normal exposure apparatus in the circular area centered on the optical axis AX of No. 4, P ≒ λ / NA _R. Therefore, it can be seen that a higher resolution than a normal exposure apparatus can be realized. Next, the reticle pattern is irradiated with exposure light in a specific incident direction and an incident angle, and a depth of focus is formed by a method of forming an imaging pattern on a wafer using the 0th-order diffracted light component and the 1st-order diffracted light component. The reason for the increase will be described.

As shown in FIG. 8, the wafer 16 is
In this case, each diffracted light that exits one point in the reticle pattern 13 and reaches one point on the wafer 16 passes through any part of the projection optical system Have the same optical path length. Therefore, even when the 0th-order diffracted light component penetrates substantially through the center (near the optical axis) of the pupil plane 15 of the projection optical system 14 as in the case of ordinary illumination, the 0th-order diffracted light component remains at
The optical path lengths of the next-order diffracted light component and the other diffracted light components are equal, and the mutual wavefront aberration is also zero. However, when the wafer 16 is in a defocused state in which the focal position of the projection optical system 14 is not coincident, the optical path length of the higher-order diffracted light obliquely incident is in front of the 0th-order diffracted light passing near the optical axis. The distance becomes shorter at a position farther from the projection optical system 14, and becomes longer at a position behind the focus (a direction approaching the projection optical system 14), and the difference depends on the difference in the incident angle. Therefore, the 0th-order, 1st-order,... Diffracted lights mutually form wavefront aberrations, causing blur before and after the focal position.

The above-mentioned wavefront aberration due to defocusing is obtained by subtracting ΔF from the focal position of the wafer 16 with each diffracted light.
The sine of the incident angle θ _w when incident on the
When _w), is an amount given by ΔFr ^2/2.
(In this case r is the diffracted light, represents the distance from the optical axis AX on the pupil plane 15. In a projection type exposure apparatus that performs conventional normal illumination, because zero-order diffracted light D ₀ passes through the vicinity of the optical axis AX , R
(0th order) = 0, while ± 1st order diffracted lights D _P and D _m are
r (1st order) = M · λ / P (M is the 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 D _m is the ^{ΔF · M 2 (λ / P} ) 2/2. On the other hand, in the projection type exposure apparatus according to the present embodiment, since the 0th-order diffracted light component D ₀ is generated in a direction inclined from the optical axis AX by an angle ψ as shown in FIG. The distance from the axis AX is r (0th order) = M · sin
ψ.

Meanwhile, 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 _m
If a -ψ), 0-order diffracted light component D ₀ and -1 relative wavefront aberration due to defocusing of the order diffracted light component D _m becomes zero, the pattern be shifted slightly in the direction of the optical axis from the wafer 16 is the focal position 13 Will not occur as much as before. That is, the depth of focus increases. Also,
As shown in equation (2), sin (θ _m −ψ) + sinψ = λ
/ P, the incident angle ψ of the illumination light beam L4 to the reticle 12 is sin ψ = λ /
With a 2P relationship, it is possible to greatly increase the depth of focus.

The positions of the fly-eye lens group (positions in a plane perpendicular to the optical axis) are preferably determined (changed) according to the reticle pattern to be transferred. A specific example of determining the position of the fly-eye lens group will be described with reference to FIGS. In FIG. 6, the distance from the fly-eye lens-side principal point of the lens 11 to the reticle-side focal plane 5b of the fly-eye lens group 5 and the distance from the reticle-side principal point of the lens 11 to the reticle pattern 13 are both f. .

FIGS. 9A and 9C are diagrams each showing an example of a partial pattern formed in the reticle pattern 13. FIG. 9B is a diagram showing the case of the reticle pattern shown in FIG. 9A. FIG. 9 shows 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. 10D is a diagram illustrating an optimum position of each fly-eye lens group (optimum center position of each fly-eye lens group) in the case of the reticle pattern of FIG. 9C.

FIG. 9A 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 regularly arranged at a pitch P in the X direction. I have. At this time, the optimum position of each fly-eye lens group is an arbitrary position on the line segment Lα in the Y direction assumed in the Fourier transform plane and on the line segment Lβ as shown in FIG. 9B. FIG. 9B shows the reticle pattern 13.
FIG. 9 is a view of the Fourier transform plane 50 (5b) with respect to the optical axis AX direction, and the coordinate system X, Y in the plane 50 is the same as FIG. 9A in which the reticle pattern 13 is viewed from the same direction. It is. Now, in FIG. 9B, 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, and when λ is the exposure wavelength, α = β = f ·
It is equal to (1/2) · (λ / P). Let these distances α and β be f
· If it can be expressed as sinψ, sinψ = λ / 2P,
This is in agreement with the above numerical values. Accordingly, if the center of each fly-eye lens group (the center of gravity of the light intensity distribution of the secondary light source image formed by each fly-eye lens group) is on the line segments Lα and Lβ, as shown in FIG. For the line-and-space pattern, two diffracted lights, one of the 0th-order diffracted light and ± 1st-order diffracted light generated by the illumination light from each fly-eye lens, are reflected on the pupil plane 15 of the projection optical system. It passes through a position approximately equidistant from the axis AX. Therefore, as described above, the depth of focus for the line and space pattern (FIG. 9A) can be maximized, and high resolution can be obtained.

Next, FIG. 9C shows a case where the reticle pattern is a so-called two-dimensional dot pattern, and
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. 9D is a diagram showing the optimal position of each fly-eye lens group in this case, and the position and rotation relationship with FIG. 9C are 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. 9C, diffracted light is generated in a two-dimensional direction according to the periodicity (X: Px, Y: Py) in the two-dimensional direction of the pattern. Even in the two-dimensional pattern as shown in FIG. 9C, one of the 0th-order diffracted light and ± 1st-order diffracted light in the diffracted light is set to be substantially equidistant from the optical axis AX on the pupil plane 15 of the projection optical system. Then, the depth of focus can be maximized. In the pattern of FIG. 9C, the pitch in the X direction is Px, so that as shown in FIG.
If the center of each fly-eye lens group is on the line segment Lα, Lβ that is f · (1/2) · (λ / Px), the X of the pattern
The depth of focus can be maximized for the directional component.
Similarly, if the center of each fly-eye lens group is on the line segments Lγ and Lε satisfying γ = ε = f · (１ ／) · (λ / Py), the depth of focus is maximized for the pattern Y-direction component. can do.

As described above, when the illumination light beam from the fly-eye lens group arranged at each position shown in FIG. 9B or 9D enters the reticle pattern 13, the 0th-order light diffracted light component D
_0, + 1-order diffracted light component D _R or -1-order diffracted light component D
Any one of _m passes through an optical path that is substantially equidistant from the optical axis AX on the pupil plane 15 in the projection optical system 14. Accordingly, as described with reference to FIG. 8, a projection exposure apparatus having a high resolution and a large depth of focus can be realized. As described above, only two examples shown in FIG. 9A or 9C are considered as the reticle pattern 13.
Focusing on the periodicity (fineness) of other patterns, two luminous fluxes of either the + 1st-order diffracted light component or the -1st-order diffracted light component and the 0th-order diffracted light component from the pattern are projected into the projection optical system. In the inner pupil plane 15, the center of each fly-eye lens group may be arranged at a position passing through an optical path that is substantially equidistant from the optical axis AX. The pattern examples in FIGS. 9A and 9C show the ratio (duty ratio) between the line portion and the space portion.
Is a 1: 1 pattern, so that ± 1st-order diffracted light becomes stronger in the generated diffracted light. For this reason, attention has been paid to the positional relationship between one of the ± 1st-order diffracted lights and the 0th-order diffracted light. However, when the pattern is different from the duty ratio of 1: 1 or the like, the other diffracted lights, 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 15 of the projection optical system.

The reticle pattern 13 is shown in FIG.
When a two-dimensional periodic pattern is included as shown in FIG. 1, when focusing on one specific zero-order diffracted light component, the pupil plane 1 of the projection optical system
5, a first-order or higher-order diffracted light component distributed in the X direction (first direction) around the one 0-order diffracted light component;
There may be first-order or higher-order diffracted light components distributed in the Y direction (second direction). Therefore, assuming that a two-dimensional pattern is favorably imaged with respect to one specific 0th-order diffracted light component, one of the higher-order diffracted light components distributed in the first direction is represented by:
One of the higher-order diffracted light components distributed in the second direction and a specific 0
The specific zero-order diffracted light component (1) is distributed such that the three diffracted light components are distributed on the pupil plane 19 at substantially the same distance from the optical axis AX.
The positions of the two fly-eye lens groups may be adjusted. For example, the center position of the fly-eye lens in FIG.
It is preferable to match any of ζ, Pη, Pκ, and Pμ.
Points Pζ, Pη, Pκ, and Pμ are line segments Lα or L
β (the position optimal for the periodicity in the X direction, that is, the position where the 0th-order diffracted light and one of the ± 1st-order diffracted lights in the X direction are approximately equidistant from the optical axis on the pupil plane 15 of the projection optical system) and the line segment L
Since this is the intersection of γ and 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.

Note that the center of light quantity on the Fourier transform plane is the optical axis A.
It is desirable to arrange so as to coincide with X. For example, two fly-eye lens groups may be arranged symmetrically with respect to the optical axis AX. The example of determining the positions of the plurality of fly-eye lens groups has been described above. However, the illumination light beam is moved by the above-described optical member (diffraction grating pattern, movable mirror, prism, fiber, or the like). However, the optical member for such concentration need not be provided.

The illumination light may be made uniform by using a light scattering member such as a diffusion plate or an optical fiber bundle near the light source side focal plane 5a of the fly-eye lens 5. Alternatively, separately from the fly-eye lens 5 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, the separate fly-eye lens is a light source side focal plane 5a of the fly-eye lens 5.
It is desirable to be closer to the light source (lamp) 1 than the optical member, for example, the prism 40, which makes the illumination light amount distribution in the vicinity variable. Further, it is desirable that the cross-sectional shape of the lens element of another fly-eye lens be a regular hexagon rather than a square (rectangle). Furthermore, as shown in FIG.
A zoom system as shown in FIG.

In the above-mentioned plurality of oblique incidence illuminations, the position and shape of the light beam passing through the pupil plane 15 differ depending on the position of each light beam and the number of light beams, so that the focal position differs. Also, the focal position is changed by switching between the multiple oblique incidence illumination and the normal illumination as shown in the first embodiment. For this reason, the focus offset is stored in advance in the main control system 33 in accordance with the condition of each of the plurality of oblique incident illuminations, and the
As described in the third embodiment, an offset may be added to the gap sensor AF in accordance with the switching of the illumination state, or focus calibration may be performed every time the illumination state is switched.

In the above embodiment, the light source is the mercury lamp 1
However, other bright line lamps, lasers (excimer, etc.), 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. Whether the projection optical system is a refraction system or a reflection system,
Alternatively, a catadioptric system may be used. 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. Furthermore, 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.

Hereinafter, the operation of this embodiment will be described.
As an example of the operation, a case where the number of illumination light beams is switched from two to four will be described. Illumination flux from 2 to 4
When the number has been switched, the focus offset value is obtained based on the switching information (barcode, keyboard, etc.). Then, by the same operation as in the first embodiment, an offset may be added to the gap sensor AF, or focus calibration may be performed each time the illumination state is switched.

When the positions of the four (or two) illumination lights are changed, an offset is applied to the gap sensor AF or the illumination state is changed by the same operation as in the first embodiment based on the switching information. Focus calibration may be performed each time the switching is performed. Conventional lighting (normal lighting)
In the case where the illumination is switched from the illumination to the multiple oblique illumination, the offset may be added to the gap sensor AF based on the switching information and the focus calibration may be performed each time the illumination state is switched. . At this time, if the offset amount exceeds the driving amount of the parallel flat glass 29 or exceeds the allowable value of the electrical offset amount, an operation of automatically performing focus calibration may be performed.

Even when switching from normal illumination to oblique illumination using one light beam, it is possible to correct the focus fluctuation by the same operation. Next, a third embodiment will be described. FIG. 10A is a diagram showing an optical path of diffracted light from the phase shift reticle, and FIG.
It is a figure which shows the state of the above-mentioned diffracted light. In FIG. 10A, the one-dot chain line indicates the -1st order diffracted light, the dotted line indicates the + 1st order diffracted light, and the aperture stop is provided with 6-B. Note that FIG.
In FIG. 1A, the lenses 7, 9, 11 and the mirror 11 of FIG. When the phase shift reticle 12b is used, a plurality of light beams pass through a position decentered from the optical axis on the pupil plane 15, as in the case of the multiple oblique incidence illumination described in the second embodiment. Therefore, when switching from the normal reticle to the phase shift reticle, it is necessary to add an offset to the gap sensor AF or perform focus calibration at the time of replacement, as in the second embodiment.

Further, an offset is added to the gap sensor AF in accordance with the switching between the case of performing the multiple oblique incidence illumination with the normal reticle and the case of using the phase shift reticle, and the focus calibration is performed at the time of replacement. Furthermore, the position and shape of the light beam formed on the pupil plane 15 may differ depending on the type of the phase shift reticle. In this case, too, an offset is added to the gap sensor AF according to the switching, and the focus calibration is performed at the time of replacement. I do.

In the above-described first to third embodiments, the different imaging conditions are as follows: normal illumination; annular illumination; plural oblique incidence illumination; use of a phase shift reticle; variable NA; variable σ value; The focus offset value is obtained in advance for each of the mutual switching and each condition change,
If each of these is selected and the stored offset amount is added to the gap sensor AF, exposure can always be performed at the best focus position even when the imaging state changes.

[0072]

As described above, according to the present invention, exposure can always be performed on the best focal plane regardless of the illumination light state and the reticle used.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a projection exposure apparatus according to a first embodiment of the present invention;

FIG. 2 is a partial view showing a case where a zoom lens system is used as a means for varying the numerical aperture of an illumination system of the apparatus of FIG. 1,

3A is a diagram showing an optical path of illumination light at a relatively large σ value in the apparatus of FIG. 1; FIG. 3B is a diagram showing diffracted light on a pupil plane of a projection optical system;

4A is a diagram showing an optical path of illumination light at a relatively small σ value in the apparatus of FIG. 1, FIG. 4B is a diagram showing diffracted light on a pupil plane of a projection optical system,

5A is a diagram showing an optical path of illumination light when a ring-shaped aperture stop is provided in the apparatus of FIG. 1, FIG. 5B is a diagram showing diffracted light on a pupil plane of a projection optical system,

FIG. 6 is a view showing a part of a projection exposure apparatus according to a second embodiment of the present invention;

FIG. 7 is a diagram showing a switching member according to a second embodiment of the present invention;

FIG. 8 is a diagram showing a basic optical path from a reticle to a wafer according to a second embodiment of the present invention;

FIGS. 9A and 9C are plan views showing examples of a reticle pattern formed on a mask, and FIGS. 9D and 9D are Fourier diagrams of reticle patterns corresponding to FIGS. 9A and 9C, respectively. FIG. 7 is a diagram illustrating the arrangement of each fly-eye lens group (surface light source image) on a conversion surface;

10A is a diagram illustrating a light beam passing through a projection optical system when a phase shift reticle is used, and FIG. 10B is a diagram illustrating diffracted light on a pupil plane of the projection optical system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source 4 ... Lens system 5, 5A, 5B, 45A, 45B, 46A, 46B, 4
7A: fly-eye lens TA, 44: turret plate 6: aperture stop 12: reticle 12b: phase shift reticle 13: reticle pattern 14: projection optical system 15: pupil plane 15a: NA stop 16: wafer 19, Z stage 21: XY Stage 24 Reference member 25 Photoelectric detectors 26, 27, 28, 29, 30, 31 Gap sensor AF 32 Focus control system 33 Main control system 34 Barcode reader 35 Keyboard 36, 37, 18, 29 , 30, 48, 49, 60 drive system 40, 41 light splitting member 42, 45, 46, 47 holding member

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (31)

(57) [Claims] An illumination optical system for irradiating illumination light to a mask,
A projection optical system for projecting the illumination light onto a substrate, wherein the illumination light on a predetermined surface that is substantially in a Fourier transform relationship with the pattern surface of the mask in the illumination optical system. Having an optical member including a plurality of prisms moving along the optical axis of the illumination optical system, and setting exposure conditions of the substrate with the illumination light according to the pattern of the mask. A projection exposure apparatus, comprising: setting means; and adjusting means for adjusting an image forming state of the pattern on the substrate in accordance with at least one of replacement of the mask and change of the exposure condition. . 2. The projection exposure apparatus according to claim 1, wherein the exposure condition includes a distribution of the illumination light on the predetermined surface and a numerical aperture of the projection optical system. 3. The projection exposure apparatus according to claim 1, wherein said adjusting means adjusts a positional relationship between an image forming plane in the optical axis direction of said projection optical system and said substrate. 4. The apparatus according to claim 1, wherein the adjusting means moves the substrate in accordance with a change in the position of an image plane of the projection optical system caused by at least one of replacement of the mask and change of the exposure condition. The projection exposure apparatus according to claim 3. 5. A detecting means for detecting position information of the substrate in an optical axis direction of the projection optical system;
Control means for controlling the movement of the movable body holding the substrate based on the position information, and giving an offset to one of the detection means and the control means in accordance with a change in the position of the imaging surface The projection exposure apparatus according to claim 4, wherein: 6. The apparatus according to claim 1, wherein said setting means moves at least a part of said optical member to increase an intensity distribution of said illumination light on said predetermined surface outside a central portion. The projection exposure apparatus according to any one of claims 1 to 5. 7. The apparatus according to claim 6, wherein said setting means adjusts a position of an outer region where said intensity distribution is enhanced on said predetermined surface by changing an interval between said plurality of prisms.
3. The projection exposure apparatus according to claim 1. 8. The projection exposure apparatus according to claim 7, wherein said optical member has a zoom lens system for adjusting the size of said outer region. 9. An illumination optical system for irradiating the mask with illumination light,
A projection exposure apparatus comprising: a projection optical system configured to project the illumination light onto a substrate. In accordance with a pattern of the mask, a pattern surface of the mask is substantially Fourier-transformed within the illumination optical system. To change the distribution of the illumination light on a predetermined surface,
A plurality of prisms and a zoom lens system that move along the optical axis of the illumination optical system, and the plurality of prisms illuminate the illumination optical system outside the center including the optical axis of the illumination optical system on the predetermined surface. A projection exposure apparatus comprising setting means for distributing light. 10. The projection exposure apparatus according to claim 9, wherein said setting means adjusts a position of an outer area where said illumination light is distributed by changing an interval between said plurality of prisms. 11. The projection exposure apparatus according to claim 9, wherein said setting means adjusts the size of an outer area in which said illumination light is distributed by said zoom lens system. 12. The projection exposure apparatus according to claim 8, wherein said zoom lens system is arranged on an incident side of said plurality of prisms. 13. The illumination optical system according to claim 1, wherein the illumination optical system has an optical integrator, and the plurality of prisms are arranged on an incident side of the optical integrator. The projection exposure apparatus according to claim 1. 14. The projection exposure apparatus according to claim 1, wherein the setting unit has a stop for defining a distribution of the illumination light on the predetermined surface. 15. The projection exposure apparatus according to claim 7, wherein the outer region includes a local region in which a light amount center of gravity is set at a position decentered from an optical axis of the illumination optical system. 16. Two diffracted lights having different orders, which are generated from the pattern by irradiating a light beam emitted from the local area, on a Fourier transform plane with respect to a pattern plane of the mask in the projection optical system. 16. The projection exposure apparatus according to claim 15, wherein the setting unit adjusts the position of the local area so that the local area is distributed substantially equidistant from the axis. 17. The projection exposure apparatus according to claim 16, wherein one of the two diffracted lights is a zero-order diffracted light. 18. The projection exposure apparatus according to claim 15, wherein said outer region includes a plurality of local regions having substantially the same distance from the optical axis of said illumination optical system. apparatus. 19. The projection exposure apparatus according to claim 18, wherein said plurality of local regions include a pair of local regions arranged along a periodic direction of said pattern. 20. The plurality of local regions include a pair of local regions that intersect the optical axis of the illumination optical system on the predetermined surface and are defined by axes extending in a longitudinal direction of the pattern. The projection exposure apparatus according to claim 18, wherein 21. The projection exposure apparatus according to claim 18, wherein the plurality of local regions are defined by first and second axes orthogonal to an optical axis of the illumination optical system on the predetermined surface. apparatus. 22. The pattern includes pattern elements extending in first and second directions orthogonal to each other, wherein the first and second axes are defined along the first and second directions, respectively. The projection exposure apparatus according to claim 21, wherein: 23. A zero-order diffracted light generated from the pattern by irradiation of a light beam emitted from each of the local regions, a non-zero-order diffracted light distributed along with the zero-order diffracted light in the first direction, and the second diffracted light. The diffracted light of the order other than the 0th order distributed along with the 0th order diffracted light in the direction is distributed almost equidistant from its optical axis on the Fourier transform plane with respect to the pattern plane of the mask in the projection optical system. 23. The apparatus according to claim 22, wherein the setting means adjusts the position of each of the local areas.
3. The projection exposure apparatus according to claim 1. 24. The outer region according to claim 1, wherein the center of gravity of the light amount substantially coincides with the optical axis of the illumination optical system.
The projection exposure apparatus according to any one of claims 8 to 23. 25. The size of the local area is determined so that the ratio of the numerical aperture of a light beam emitted from the local area to the numerical aperture of the projection optical system is about 0.1 to 0.3. The projection exposure apparatus according to any one of claims 15 to 24, wherein: 26. A circuit element forming method, comprising a lithography step of transferring a circuit pattern formed on a mask onto a substrate by using the projection exposure apparatus according to any one of claims 1 to 25. Method. 27. A method of irradiating a mask with illumination light through an illumination optical system and exposing a substrate with the illumination light through a projection optical system, comprising: moving a plurality of prisms and a zoom lens system in the illumination optical system. Controlling the distribution of the illumination light on a predetermined surface in the illumination optical system having a substantially Fourier transform relationship with the pattern surface of the mask, outside the center including the optical axis of the illumination optical system. And a projection exposure method. 28. The apparatus according to claim 27, wherein a distance between the plurality of prisms in the optical axis direction of the illumination optical system is changed, and a position of an outer area where the illumination light is distributed on the predetermined surface is adjusted. 3. The projection exposure method according to 1. 29. A method of irradiating a mask with illumination light through an illumination optical system and exposing a substrate with the illumination light through a projection optical system, comprising: By adjusting the interval, on a predetermined surface in the illumination optical system that is substantially in a Fourier transform relationship with the pattern surface of the mask, the illumination light is emitted outside a center portion including the optical axis of the illumination optical system. A projection exposure method, comprising distributing and correcting a change in optical characteristics of the projection optical system caused by setting the distribution of the illumination light. 30. The zoom lens system according to claim 27, wherein a zoom lens system in said illumination optical system is moved to adjust a size of an outer area on said predetermined surface where said illumination light is distributed.
The projection exposure method according to any one of the above. 31. A method of forming a circuit element, comprising: a lithography step of transferring a circuit pattern formed on a mask onto a substrate by using the projection exposure method according to claim 27. Method.