JPH0653119A - Projection type exposure system - Google Patents

Abstract

(57) [Abstract] [Purpose] Exposure is always performed at the best focal plane, regardless of changes in the illumination light state or replacement of the normal reticle and the phase shift reticle. The light flux from the light source 1 is limited to a predetermined shape by an aperture stop 6. The turret plate TA can switch a plurality of aperture stops having different aperture shapes. Further, the normal reticle 12 and the phase shift reticle 12b can be switched. An offset is added to the gap sensor AF in response to a change in the state of the illumination light or a switching between the normal reticle and the phase shift reticle.

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 focus for switching an illumination system of a projection exposure apparatus used for transferring a circuit pattern of a semiconductor integrated device or a liquid crystal element pattern. The present invention relates to adjustment and focus adjustment accompanying switching of a mask to be used.

[0002]

2. Description of the Related Art Generally, a process called a photolithographic technique is required for forming a circuit pattern of a semiconductor or the like.
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 the circuit pattern is transferred to the photoresist according to the irradiation light image, that is, the pattern shape of the transparent portion of the mask pattern. In the 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 the conventional projection type exposure apparatus, the light amount distribution of the illumination light flux incident on the surface corresponding to the Fourier transform of the mask or the surface in the vicinity thereof is within a substantially circular shape (or within a rectangular shape) about the optical axis of the illumination optical system. It was set to be almost uniform at (normal lighting). When the pattern pitch becomes finer, the diffraction angle of the light flux passing through the mask becomes larger, 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 to use a projection optical system having a larger numerical aperture. Of course, efforts can be considered to optimize both the wavelength and the numerical aperture. However, in the conventional exposure apparatus, the wavelength of the illumination light source is shorter than that at present (for example, 200
However, it is difficult at this time because there is no suitable optical material that can be used as a transmissive 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 increase the numerical aperture further. In addition, even if it is possible to make the aperture larger than the current one, the depth of focus represented by ± λ / 2NA ² decreases sharply as the numerical aperture increases, and the depth of focus required for actual use becomes smaller and smaller. The problem of becoming

Therefore, in recent years, Japanese Patent Laid-Open No. 2-50417 discloses that an illumination optical system and a projection optical system are provided with an aperture stop concentric with the optical axis to restrict the incident angle of the illumination light with respect to the mask. Accordingly, 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 material substrate. Further, it has been proposed to increase the depth of focus (ring illumination) by providing a ring-shaped aperture stop in which a ring-shaped light transmitting portion is formed concentrically around the optical axis in the illumination system.

Further, by making the illumination light incident on the mask at a predetermined incident angle, the 0th-order light and the 1st-order diffracted light passing through a position decentered from the optical axis on the pupil plane in the projection optical system are caused to interfere with each other to obtain a resolution. Has been proposed (tilted illumination). On the other hand, of the transparent part of the circuit pattern of the mask,
A so-called phase shift mask, which shifts the phase of transmitted light from a specific portion by π from the phase of transparent light from another transmitted portion, is proposed in Japanese Patent Publication No. 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 flux passing through the projection optical system in the pupil plane change variously. 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,
One parameter of the illumination system, σ value, is σ = NAi / N
Defined in A. This σ value is conventionally about 0.5, and when performing a conventional illumination method (normal illumination) or using a normal mask, the diffracted light from the mask causes the optical axis of the projection optical system in the pupil plane. It was spread over the entire opening (pupil surface).
On the other hand, for example, in the phase shift mask, the σ value is 0.
It is used as about 3.

Further, since the light flux including the optical axis disappears in the pupil plane due to the principle of phase shift, the light flux only passes through a partial peripheral region in the pupil plane of the projection optical system. Further, even when the above-mentioned ring-shaped illumination or tilted illumination is performed, there is no light flux including the optical axis in the pupil plane as in the case of the phase shift mask, and the light flux passes only in the peripheral area in the pupil plane. In this way, if the σ value changes or the state of light flux passage in 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. A slight change occurs in the focal position of.

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

[0011]

To achieve the above object, according to the present invention, an illumination optical system for illuminating illumination light from a light source (1) onto a mask (12) having a fine pattern and a pattern image of the mask are provided. A projection optical system (14) for performing projection exposure on a substrate (16), a stage (19) that holds the substrate and is movable in the optical axis direction of the projection optical system, and a predetermined connection of the projection optical system with respect to 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 a 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. And input means (34, 35) for inputting information on at least one of the shape of the light beam passing through the Fourier transform surface of the mask in the projection optical system and the position of the light beam passing through the Fourier transform surface; Setting means (6, 15a, 6) for setting a predetermined exposure condition based on the information from
0, 40, 41, 5, 12b); switching means (TA, 37, 4) for switching the exposure condition set in the setting means
9, 44, 38, 61); adjusting means for adding an offset to either one of the focus detecting means and the control means by a value corresponding to the change in the position of the predetermined image plane in the optical axis direction, which is changed by the switching by the switching means. (33, 32) and.

[0012]

According to the present invention, even if the focus position is changed by changing the shape of the illumination light or exchanging the normal mask and the phase shift mask, the exposure at the best focus position can always be realized.

[0013]

1 shows the construction of a projection type exposure apparatus according to an embodiment of the present invention. The illumination luminous flux generated from the mercury lamp 1 is focused on the second focal point f ₀ of the elliptic mirror 2,
The light enters the 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
This is for making the intensity distribution of the illumination light radiated onto the beam 2 uniform. The reticle side focal plane 5 of the fly-eye lens 5
An aperture stop 6 is provided near a. The aperture stop 6 is provided with an opening 6 a that limits the 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 size of a, which determines the σ value.

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

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

FIG. 2 shows the fly-eye lens 5 shown in FIG.
2 shows an optical configuration on the light source side, and in the figure, the afocal variable magnification optical system 60 includes a positive first lens group 60a, a negative second lens group 60b, and a positive second lens group 60b. It is composed of one lens group 60c. Then, as shown in FIGS. 2A and 2B, each lens group (60a-6
0c) is moved to achieve zooming, and the size of the secondary light source formed on the exit side of the fly-eye lens can be varied without blocking light. Further, the entrance side surface 5a of the fly-eye lens is also provided substantially conjugate with the aperture 2a of the elliptic mirror with respect to the input lens 4 and the afocal variable magnification optical system 60 due to the variable magnification of the afocal variable magnification optical system 60. . Thereby, while maintaining the double conjugate relation with the object plane and the pupil plane (Fourier plane),
The value can be variable.

Returning to FIG. 1, the light beam L1 emitted from the opening 6a is guided to the reticle blind 8 by the relay lens 7. The reticle blind 8 is a field stop provided on a surface almost conjugate with the reticle pattern 13 and illuminating only a specific area on the reticle 12, and its size is variable 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. Light flux L1 is reticle pattern 13
The diffracted light generated from
Focused and imaged on top. In addition, the drive unit 37 uses the NA diaphragm 15
The size of the pupil plane 15 of the projection optical system is made variable by driving a, and the NA of the projection optical system 14 can be changed to a desired value.

The wafer 16 is vacuum-sucked to a wafer chuck 17, and the wafer chuck 17 is provided on a Z stage 19 which can be moved in the Z direction (optical axis direction) by a motor 18. Further, the Z stage 19 is provided on an XY stage 21 which can be two-dimensionally moved by a motor 20,
A reflection mirror 23 that reflects the laser beam from the laser interferometer 22 is provided at the end of the Z stage. The position of the XY stage 21 is set to 0.
It is always detected with a resolution of 01 μm.

On the XY stage 21, a reference member (glass substrate) 24 provided with a feeder mark used for detecting a focus position (image forming position) is made to substantially coincide with the surface position of the wafer 16. It is provided. Although not shown in this embodiment, two sets of light-transmitting slit patterns (bar patterns) are formed as feeder marks extending in the X and Y directions, respectively. Further, inside the Z stage 19, a photoelectric detector 25 such as a PIN photodiode is arranged close to the reference member 24. In this embodiment, a focus detection measurement pattern of the reticle 12 (for example, a light transmissive cross) is provided. The illumination light that has passed through the slit is received via the slit pattern. In FIG. 1, the projected image of the circuit pattern is shown 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 formation position (focus position) of the focus position measurement pattern by the projection optical system 14 is detected.
This focus detection method is disclosed in Japanese Patent Laid-Open No. 59-094032.

Further, 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. A light beam from the projector 26 is obliquely incident on the optical axis AX toward a predetermined image forming plane 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. , Receives light through the parallel plate glass 29 and outputs 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 control unit 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 be always matched with a predetermined image plane.

When the gap sensor AF is provided with an offset, the angle of the parallel plate glass 24 is set to the drive unit 3.
The position of the reflected light incident on the position detector may be shifted from the center by changing it by 0, or the output from the position detector may be offset. The configuration of the gap sensor AF is not limited to this, and a synchronous detection method as disclosed in Japanese Patent Laid-Open No. 60-168112 may be used. Further, a gap sensor may be used which irradiates slit-shaped light that covers the entire image feed of the projection optical system and detects reflected light by each of the detectors divided into a plurality of areas.

By the way, in FIG. 1, a main control system 33 for integrally controlling the apparatus and a name formed on the side of the reticle pattern 13 while the reticle 12 is being carried by the reticle carrying system 38 directly above the projection optical system 14. Bar code BC
A bar code reader 34 for reading and a keyboard 35 for inputting commands and data from an operator are provided. In the main control system 33, the names of a plurality of reticles to be handled by this stepper and the operation parameters of the stepper corresponding to each name are registered in advance. When the bar code reader 34 reads the reticle bar code BC, the main control system 33 reads the reticle bar code BC as one of the operation parameters corresponding to the name and pre-registers the aperture diaphragm 6.
Information such as the NA aperture of the projection optical system 14 and the driving unit 36,
Output to the drive unit 37. This adjusts the optimum illumination light shape (normal or annular), the optimum illumination condition such as σ value, and the optimum NA of the projection optical system.

The main control system 33 includes a gap sensor AF according to the illumination light shape, σ value, NA, etc. as one of the parameters.
A focus offset value that gives an offset to the reticle is stored in correspondence with the reticle name (bar code 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 switching of illumination conditions such as σ value and switching of NA, is selected as a parameter.

The focus offset value is obtained in accordance with illumination conditions such as σ value, NA, etc., and serves as information for coping with changes in a predetermined image plane. This offset value may be recorded on the reticle as bar code information. In addition, trial baking or the like is performed in advance to find the best image formation surface 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). It may be recorded in the memory of.

The above operation can also be executed by the operator directly inputting commands and data to the main control system 33 from the keyboard 35. Further, every time at least one of the σ value, NA, and each illumination light shape is selected / set, the best image formation plane may be obtained using the above-mentioned 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 FIG. 3, FIG. 4, and FIG.
In (a), FIG. 4 (a), and FIG. 5 (a), the solid line indicates the 0th-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 simplified and shown as a mirror 11. Figure 3
FIG. 3A shows a basic optical path in the case where the size of the opening 6a is set so that the σ value becomes about 0.5 (aperture stop 6-A), and FIG. 3B shows FIG. 0 on pupil plane 15
Next, the ± 1st order light spread is shown. 4A and 4B show the basic optical path and the 0th order on 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). , The spread of ± 1st order light is shown. 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 part.
5 shows the spread of the 0th and ± 1st order lights. Figure 2
As shown in (b), FIG. 3 (b), and FIG. 4 (b), the pupil plane 1
The position of the light flux passing through 5 differs greatly depending on the shape of the opening, and the spherical aberration and the amount of light absorption 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. Also in FIGS. 3 and 4, since the position (or shape) of the light flux passing through the pupil plane 15 is different and the size of the aperture stop is different, the light absorption amount and the spherical aberration are different, and the position of the best imaging plane is different. Furthermore, the absorption of light heats the lens in the projection optical system, causing a change in the refractive index and expansion. The focus position of the projection optical system may change due to this lens change.

Therefore, it is necessary to add an offset to the gap sensor AF for each illumination light shape depending on the amount of light absorption and the residual spherical aberration. Next, a typical operation of this embodiment will be described. The bar code BC provided on the reticle 12 is read by the bar code reader 34, and the optimum illumination conditions (illumination light shape, σ) corresponding to the reticle 12 are read.
Value) and NA. Here, it is assumed that the driving 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 transfer system 38 exchanges the reticle. The bar code BC provided on the reticle after replacement is read by the bar code reader 34 and the optimum illumination condition is selected. Here, it is assumed that the ring stop 6-C as shown in FIG. 5 is selected. Σ for barcode information
Illumination conditions such as values and NA information are recorded. The 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 amounts are set to the gap. Add to sensor AF. As a result, even when the illumination conditions such as the σ value and the NA are changed,
Exposure can be performed while the surface of the wafer 16 is always aligned with the predetermined image plane.

In addition, the Z stage 1 is moved by an amount corresponding to the focus difference.
9 is moved up and down 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. Alternatively, the reference member 24 may be used to detect the focus position each time the reticle is replaced, and the reference member 24 may be moved to this focus position.
It is also possible to move the Z stage 19 so that the surface of is positioned and perform focus calibration at this focus position.

Further, an offset may be added to the position of the reticle or Z stage 19 in the optical axis direction. Here, in the case where the projection exposure apparatus according to the present embodiment is provided with a control system or the like for controlling the pressure between the plurality of lens elements, a parallel plate is used because the imaging fluctuation occurs due to the accumulation of the irradiation amount in the projection optical system. The glass is tracking-controlled so as to sequentially offset the focus position. Therefore, as in the present invention, the offset with respect to the image plane displacement due to at least one change of illumination conditions such as σ value and 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 JP-A-63-58349.

The projection type exposure apparatus according to the present embodiment is provided with a control system for controlling the pressure between a plurality of lens elements of the projection optical system as disclosed in Japanese Patent 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, and tilted illumination in which the 0th-order light and the ± 1st-order diffracted lights that pass on the pupil plane 15 are separated and passed through the positions decentered from the optical axis AX are also conceivable. In particular, although it has been filed by the applicant of the present application and has not been publicly known, the luminous flux from the light source is divided into a plurality of illumination lights (for example, 2 or 4), and the inclined illumination is performed by each of the illumination lights. An exposure apparatus for performing the exposure has been proposed.
(Hereinafter, in this specification, such oblique illumination performed by a plurality of light fluxes is referred to as “multiple oblique incidence illumination”.) 0 on the pupil plane 15
The focal position also changes depending on the positions where the second-order light and the ± first-order diffracted lights pass and the number of illumination lights.

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

Illumination light from the light source 1 enters the light splitting members 40 and 41 through 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 luminous flux is a separate fly-eye lens 5
It is incident on A and 5B. Here, the fly-eye lens group 5
Although there are two A and 5B, this quantity may be arbitrary. The light splitting member may also be split into any number according to the number of fly-eye lens groups. For example, if the fly-eye lens group is composed of four, the light splitting members 40 and 41 may each be a pyramid-type polygonal prism.

The light beams L2 and L3 emitted from the fly-eye lens groups 5A and 5B are incident on the reticle 12 through the lens 11 at a predetermined angle with respect to the optical axis AX. The reticle-side focal plane 5b 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's eye lens group 5
In the vicinity of the reticle side focal plane 5b of A and 5B, there is provided a spatial filter 43 having an opening corresponding to the size of the individual fly-eye lens groups 5A and 5B, which shields unnecessary light beams. There is.

The light splitting member is not limited to a prism, but 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). But it's okay. Further, 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 is the fly-eye lens group 5
Centers of A and 5B (in other words, fly-eye lens group 5
The center of gravity of each light amount distribution formed by the secondary light source image in each of A and 5B is set at a discrete position 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) is provided with the holding member 42 and the optical axes AX of the plurality of fly-eye lens groups according to the difference in the periodicity of the reticle pattern 13.
A plurality of holding members (not shown) for holding the eccentricity states different from each other are integrally fixed, and by driving the movable member 44 by the drive member 48, each of the plurality of holding members can be replaced. It can be placed 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 at intervals of about 90 ° on a movable member (turret plate) 44 rotatable about a rotation shaft 44a. Illumination light fluxes 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 of the holding member 42 and the optical axis AX substantially coincide with each other. 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 according to the periodicity of the reticle pattern.
They are integrally held by the holding member 42 so as to be set at discrete positions decentered with respect to X, and here, they 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,
In each of the reference numerals 47, a plurality of fly-eye lens groups are arranged in an eccentric state with respect to the optical axis AX (center of the holding member) according to 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. The holding members 42 and 45 both have two fly-eye lens groups (5A, 5B) and (45A, 45B),
When these fly-eye lens groups are arranged in the illumination optical system, they are fixed such 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 the center 46cA thereof.
It is arranged and fixed at an approximately equal distance from (optical axis AX). The holding member 47 is fixed so 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 the illumination state as in the first embodiment. still,
When the spatial filter 43 is provided in the holding members 4, 45, 46, 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, according to the information of the reticle bar code BC, each of the four holding members 42, 45, 46 and 47 can be replaced by rotating the turret plate 44 by the drive element 48 including a motor and a gear. It is possible to arrange a desired holding member in the illumination optical system according to the periodicity (pitch, arrangement direction, etc.) of the reticle pattern. Further, by adjusting the distance between the prism 40 and the prism 41 by the driving member 48, the position of the illumination light flux on the Fourier transform surface 50 is changed, and the illumination light flux is adjusted according to each of the fly-eye lens groups having different decentered states. Can be incident. Further, the fly-eye lens group and the light splitting member may be integrally held so that they can be exchanged as one unit.

Further, as described above, the reticle barcode BC
According to the information of (1), whether to perform exposure (normal illumination) as in the first embodiment or multiple oblique incidence illumination is selected, and when performing exposure of normal illumination, the holding member 47 is selected and multiple oblique incidence is performed. When illuminating, any one of the holding members 42, 45 and 46 may be selected. When performing conventional exposure, the holding member 47 is selected and the light beam splitting member is replaced with a predetermined optical system. Further, when the lens 4 can concentrate the illumination light on the fly-eye lens group, it suffices to retract the light beam splitting member from the optical path.

Further, in FIG. 6, the spatial filter 43 is arranged behind the holding member 42 (on the side of the reticle), but if each of the holding members except the fly-eye lens group serves as a light-shielding portion, the spatial filter 43 is particularly provided. There is no need to provide it.
At this time, the turret plate 44 may be a transmissive portion or a light shielding portion. Further, the number of holding members to be fixed to the turret plate 44, and the eccentricity (position) of the plurality of fly-eye lens groups are not limited to those shown in FIG. 7, but may vary depending on the periodicity of the reticle pattern to be transferred. It may be set arbitrarily depending on the situation. Further, when it is necessary to strictly set the incident angle of the illumination light flux to the reticle pattern, each of the plurality of fly-eye lens groups in the holding member is set in the radial direction (radiation direction) about the optical axis AX. Further, the holding members (fly-eye lens groups 5A and 5B) may be configured to be finely movable and to be rotatable about the optical axis AX.
At this time, particularly when an optical fiber is used as the light beam splitting member, the exit end of the fly-eye lens group is moved along with the movement of the fly-eye lens group. For example, the exit end and the fly-eye lens group are integrally formed. It should be fixed. Further, although the rectangular fly's eye lens group also tilts relatively with the rotation of the holding member, when the holding member is rotated, only the position of the fly eye lens group moves without causing the tilt. It is desirable to configure The fly-eye lens is usually a quadrangle, but it is desirable that these four sides be 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 each exit end of the fly-eye lens group) is
Numerical aperture of the illumination light flux passing through the aperture with respect to the reticle 12 and reticle-side numerical aperture (NA _R ) of the projection optical system 14.
It is desirable to 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 deteriorated, 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 determined by one of the fly-eye lens groups (about 0.1 < σ < 0.3), the size of the exit end area of each fly-eye lens group 5A, 5B is large. The (size in the in-plane direction perpendicular to the optical axis) may be determined according to the illumination light flux (emitted light flux). Also,
Reticle-side focal plane 5 of each fly-eye lens group 5A, 5B
A variable aperture stop (spatial filter 43
(Equal to the above) may be provided to change the numerical aperture of the light flux from each fly-eye lens group to change the σ value. At the same time, the NA of the projection system can be made variable by a variable aperture stop (NA limiting stop) 15a provided near the pupil (incident pupil or exit pupil) 15 in the projection optical system 14. Alternatively, the lens system 4 may be a zoom lens system to optimize the σ value.

Now, FIG. 8 shows the reticle 12 to the wafer 16
FIG. 3 is a diagram schematically showing the basic optical path up to the above, and the state of incidence of the light beam L2 on the reticle and image formation on the wafer 16 will be described using this. The circuit pattern 13 drawn on the reticle (mask) generally contains many periodic patterns. From the reticle pattern 13 irradiated with the illumination light from one fly-eye lens group 5A, the 0th-order diffracted light component D ₀ and the ± 1st-order diffracted light components D _P , D _m, and higher-order diffracted light components are fine patterns. It occurs in the direction according to the degree.

At this time, the illumination luminous flux (chief ray) is inclined
Since the light enters the reticle 12 at an angle,
The diffracted light component also has an inclination (angle) more than that when vertically illuminated.
It occurs from the reticle pattern 13 with a deviation.
The illumination light L2 in FIG. 7 is tilted by ψ with respect to the optical axis.
The incident light L4 on the reticle 12 is the reticle pattern.
And is inclined by ψ with respect to the optical axis AX.
0th order diffracted light D₀, Θ for 0th order diffracted light_PIs
Inclined + 1st-order diffracted light D_P, And zero-order diffracted light D ₀Against
Θ_mOnly tilted-first-order diffracted light D_mTo occur. Shi
However, the illumination light L2 is projected on both sides by telecentricity.
The optical system 14 is tilted by an angle ψ with respect to the optical axis AX.
Since it is incident on the red pattern, the 0th-order diffracted light D₀Also projected
Travels in a direction inclined by an angle ψ with respect to the optical axis AX of the optical system.
To do.

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

Here, it is assumed that both the + 1st order diffracted light D _P and the −1st order diffracted light D _m are transmitted through the pupil 15 of the projection optical system 14. When the diffraction angle increases with the miniaturization of the reticle pattern 13, it first proceeds in the direction of the angle θ _P + ψ +
The first-order diffracted light D _P cannot pass through the pupil 15 of the projection optical system 14. That is, the relationship of sin (θ _P + ψ)> NA _R is established. However, since the illumination light L2 is incident while being inclined with respect to the optical axis AX, the −1st-order diffracted light D _m can enter the projection optical system 14 even at the diffraction angle at this time. Ie s
The relationship is in (θ _m −ψ) <NA _R.

Therefore, the 0th-order diffracted light D ₀ is formed on the wafer 16.
And -1st order diffracted light D _m causes interference fringes due to two light beams. This interference fringe is an image of the reticle pattern 13, and when the reticle pattern 13 has a 1: 1 line and space, the contrast is about 90% and the image of the reticle pattern 13 is formed on the resist applied on the wafer 16. It becomes possible to pattern.

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

Assuming that sin ψ is set to about 0.5 × NA _R as an example, the minimum pitch of the pattern on the transferable reticle is P = λ / (NA _R + 0.5NA _R ) = 2λ / 3NA _R ( 5) becomes.

On the other hand, the distribution of the illumination light on the Fourier transform plane 50 for the reticle 12 in the illumination system is the projection optical system 1
In the case of an ordinary exposure apparatus within a circular region centered on the optical axis AX of 4, P≈λ / NA _R. Therefore, it can be seen that a higher resolution can be realized than that of an ordinary exposure apparatus. Then, the exposure light is applied to the reticle pattern at a specific incident direction and an incident angle, and the depth of focus is also determined by a method of forming an imaging pattern on the 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 projected onto the projection optical system 14.
When it coincides with the focal point position (best image plane) of each, the diffracted light that exits one point in the reticle pattern 13 and reaches one point on the wafer 16 passes through which part of the projection optical system 12. However, they all have the same optical path length. Therefore, even when the 0th-order diffracted light component penetrates almost the center (near the optical axis) of the pupil plane 15 of the projection optical system 14 as in normal illumination,
The optical path lengths of the second-order diffracted light component and the other diffracted light components are equal to each other, and the mutual wavefront aberration is also zero. However, when the wafer 16 is in a defocused state where it does not coincide with the focal position of the projection optical system 14, the optical path length of the obliquely incident high-order diffracted light is in front of the focal point with respect to the 0th-order diffracted light passing near the optical axis ( The distance becomes short in the direction away from the projection optical system 14 and becomes long in the rear of the focus (direction closer to the projection optical system 14), and the difference depends on the difference in the incident angle. Therefore, the diffracted lights of the 0th, 1st, ... Form wavefront aberrations mutually, and blurring occurs before and after the focal position.

As for the wavefront aberration due to the above defocus, the amount of deviation from the focus position of the wafer 16 is ΔF, and each diffracted light is −
The sine of the incident angle θ _w when it is incident on r is r (r = sin θ
When _w), 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 15. In a conventional projection type exposure apparatus that performs normal illumination, the 0th-order diffracted light D ₀ passes near the optical axis AX. , R
(0th order) = 0, while the ± 1st order diffracted lights D _P and D _m are
r (1st) = 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 exposure apparatus according to the present embodiment, as shown in FIG. 8, the 0th-order diffracted light component D ₀ is generated in the direction inclined by the angle ψ with respect to the optical axis AX. The distance from the axis AX is r (0th order) = M · sin
ψ.

On the other hand, the distance of the −1st-order diffracted light component D _m from the optical axis on the pupil plane is r (−1st) = M · sin (θ _m −
ψ). Then, at this time, sin ψ = sin (θ _m
−ψ), the relative wavefront aberration due to defocusing of the _0th-order diffracted light component D ₀ and the −1st-order diffracted light component D _m becomes zero, and even if the wafer 16 is slightly deviated from the focus position in the optical axis direction, the pattern 13 The image blur of (1) will not occur as much as in the past. That is, the depth of focus is increased. Also,
As in the formula (2), sin (θ _m −ψ) + sin ψ = λ
/ P, the incident angle ψ of the illumination light flux L4 onto the reticle 12 is sin ψ = λ / with respect to the pattern of the pitch P.
With the relationship of 2P, the depth of focus can be extremely increased.

Now, each position of the fly-eye lens group (position in the plane perpendicular to the optical axis) is 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. 6 and 9. In FIG. 6, it is assumed that 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. .

9A and 9C are diagrams showing an example of a partial pattern formed in the reticle pattern 13, and FIG. 9B shows the case of the reticle pattern of FIG. 9A. 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) is shown in FIG.
FIG. 9D is a diagram showing the optimum position of each fly eye lens group (the 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 the transmissive portion and the light-shielding portion are arranged in a strip shape in the Y direction with the same width, and they are regularly arranged in the X direction at a pitch P. There is. At this time, the optimum positions of the individual fly-eye lens groups are arbitrary positions on the line segment Lα and the line segment Lβ in the Y direction assumed in the Fourier transform plane, as shown in FIG. 9B. FIG. 9B shows the reticle pattern 13
FIG. 9A is a view of the Fourier transform surface 50 (5b) of FIG. 9 from the optical axis AX direction, and the coordinate systems X and Y in the surface 50 are the same as those of FIG. 9A in which the reticle pattern 13 is viewed from the same direction. There 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). This distance α, β is f
If expressed as sin ψ, sin ψ = λ / 2P,
This is in agreement with the above figures. Therefore, if the center of each fly-eye lens group (the center of gravity of the light amount distribution of the secondary light source image created by each fly-eye lens group) is on the line segments Lα and Lβ, as shown in FIG. 9 (A). For the line-and-space pattern, two diffracted lights, one of the 0th-order diffracted light and the ± 1st-order diffracted light generated by the illumination light from each fly-eye lens, are reflected by the pupil plane 15 of the projection optical system. It passes through a position that is 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 X direction (horizontal direction) pitch of the pattern is Px, and the Y direction (vertical direction) pitch is Py. FIG. 9D is a diagram showing the optimum position of each fly-eye lens group in this case, and the position and rotation relationship with FIG. 9C are shown in FIG.
This is the same as the relationship (B). When illumination light enters a two-dimensional pattern as shown in FIG. 9C, diffracted light is generated in the two-dimensional direction according to the periodicity (X: Px, Y: Py) of the pattern in the two-dimensional direction. Even in the two-dimensional pattern as shown in FIG. 9C, one of the 0th order diffracted light and the ± 1st order diffracted light in the diffracted light should be substantially equidistant from the optical axis AX on the projection optical system pupil plane 15. By doing so, the depth of focus can be maximized. Since the pitch in the X direction is Px in the pattern of FIG. 9C, as shown in FIG. 9D, α = β =
If the center of each fly-eye lens group is on the line segments Lα and Lβ that are f · (½) · (λ / Px), the pattern X
The depth of focus can be maximized for the directional component.
Similarly, if there is the center of each fly-eye lens group on the line segments Lγ and Lε such that γ = ε = f · (1/2) · (λ / Py), the depth of focus is maximized for the pattern Y direction component. can do.

As described above, when the illumination light flux from the fly-eye lens group disposed at each position shown in FIG. 9B or 9D enters the reticle pattern 13, the 0th-order diffracted light component D
₀ and + 1st order diffracted light component D _R or -1st 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. Therefore, as described with reference to FIG. 8, a projection type exposure apparatus with a high resolution and a large depth of focus can be realized. As described above, only the two examples shown in FIG. 9A or 9C were considered as the reticle pattern 13.
Even in other patterns, paying attention to the periodicity (fineness), the two light fluxes of either the + 1st-order diffracted light component or the -1st-order diffracted light component and the 0th-order diffracted light component from that pattern are projected into the projection optical system. On the inner pupil plane 15, the centers of the fly-eye lens groups may be arranged at positions such that they pass through an optical path that is substantially equidistant from the optical axis AX. In the pattern examples of FIGS. 9A and 9C, the ratio of the line portion and the space portion (duty ratio)
Is a 1: 1 pattern, the ± 1st order diffracted light becomes strong in the generated diffracted light. Therefore, the positional relationship between one of the ± 1st-order diffracted lights and the 0th-order diffracted light is focused, but when the pattern is different from the duty ratio of 1: 1 or the like, one of the ± 2nd-order diffracted lights is used. The positional relationship between the 0th-order diffracted light and the 0th-order diffracted light may be substantially equidistant from the optical axis AX on the projection optical system pupil plane 15.

Further, the reticle pattern 13 is shown in FIG.
In the case of including a two-dimensional periodic pattern as shown in FIG.
5, the one or more high-order diffracted light components distributed in the X direction (first direction) centering on the one zero-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 satisfactorily formed on one specific 0th-order diffracted light component, one of the higher-order diffracted light components distributed in the first direction,
One of the higher-order diffracted light components distributed in the second direction and a specific 0
The three 0th-order diffracted light components are distributed in the pupil plane 19 at almost the same distance from the optical axis AX.
The positions of the two fly-eye lens groups) may be adjusted. For example, in FIG. 9D, the center position of the fly-eye lens is point P.
It is preferable to match any one of ζ, Pη, Pκ, and Pμ.
The points Pζ, Pη, Pκ and Pμ are all line segments Lα or L
β (the optimum position for 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 substantially equidistant from the optical axis on the projection optical system pupil plane 15) and the line segment L
Since it is the intersection of γ and Lε (the optimum position for the periodicity in the Y direction), it is the optimum light source position in both the X direction and the Y direction.

The center of gravity of the 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 a plurality of fly-eye lens groups has been described above. The illumination light flux is moved by the above-mentioned optical members (diffraction grating pattern, movable mirror, prism, fiber, etc.) However, it is not necessary to provide an optical member for such concentration.

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, in addition to the fly-eye lens 5 used in the embodiments of the present invention, an optical integrator such as a fly-eye lens (hereinafter, another fly-eye lens) may be used to make the illumination light uniform. At this time, the separate fly-eye lens is the light source side focal plane 5a of the fly-eye lens 5 described above.
It is desirable that it is closer to the light source (lamp) 1 side than the optical member, such as the prism 40, which makes the illumination light amount distribution in the vicinity variable. Furthermore, it is desirable that the cross-sectional shape of the lens element of another fly-eye lens is a regular hexagon rather than a square (rectangle). Furthermore, as shown in FIG.
You may provide a zoom system as shown in FIG.

In the above-described multiple oblique incidence illumination, the focal position is different because the position and shape of the light beam passing through the pupil plane 15 are different depending on the position of each light beam and the number of light beams. Further, 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 respective conditions of the multiple grazing incidence illumination, and the first
As described in the embodiment, the gap sensor AF may be offset according to the switching of the illumination state, or the focus calibration may be performed every time the illumination state is switched.

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

The operation of this embodiment will be described below.
As an example of the operation, a case where the number of illumination light fluxes is switched from 2 to 4 will be described. Illumination luminous flux from 2 to 4
When switching to individual pieces, the focus offset value is obtained based on the switching information (bar code, keyboard, etc.). Then, by the same operation as that of the first embodiment, it suffices to add an offset to the gap sensor AF or perform focus calibration every time the illumination state is switched.

When the positions of the four (or two) illumination lights change, an offset is added to the gap sensor AF or an illumination state is obtained by the same operation as the first embodiment based on the switching information. It suffices to perform focus calibration every time the switching is performed. Conventional lighting (normal lighting)
In the case of switching from a plurality of oblique incidence illuminations as well, an offset may be added to the gap sensor AF or a focus calibration may be performed every time the illumination state is switched, by the same operation as in the first embodiment based on the switching information. . 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, focus calibration may be automatically performed.

Further, even when the normal illumination is switched to the inclined illumination using one light flux, the focus fluctuation can be corrected by the same operation. Next, a third embodiment will be described. FIG. 10A is a diagram showing the optical path of the diffracted light from the phase shift reticle, and FIG. 10B is the pupil plane 15.
It is a figure which shows the state of the diffracted light above. In FIG. 10A, the alternate long and short dash 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. Incidentally, FIG.
In FIG. 1A, the lenses 7, 9, 11 and the mirror 11 in FIG. 1 are simplified and shown as a mirror 11. 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 multiple oblique incidence illumination described in the second embodiment. Therefore, when the normal reticle is switched 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. Further, even in the phase shift reticle, the position and shape of the light beam formed on the pupil plane 15 may differ depending on the type, and in this case as well, an offset is added to the gap sensor AF according to the switching, or a focus calibration is performed at the time of replacement. I do.

In the above-mentioned first to third embodiments, different image formation states are obtained when normal illumination is performed: annular illumination 〃 multiple oblique incidence illumination 〃 when phase shift reticle is used NA variable 〃 σ value variable 〃 Is considered, and the focus offset value is obtained in advance for each of the mutual switching of-and each condition change,
When each of these is selected, if the stored offset amount is added to the gap sensor AF, exposure can always be performed at the best focus position even when the image formation state changes.

[0072]

As described above, according to the present invention, it is possible to always perform exposure with the best focal plane regardless of the illumination light state and the reticle used.

[Brief description of drawings]

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

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

3A is a diagram showing an optical path of illumination light with a relatively large σ value in the apparatus of FIG. 1, and 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 with 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 in the case where a ring-shaped aperture stop is provided in the apparatus of FIG. 1, and FIG. 5B is a diagram showing diffracted light on a pupil plane of a projection optical system.

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

FIG. 7 is a view 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 in the second embodiment of the present invention,

9A and 9C are plan views showing an example of a reticle pattern formed on a mask, and FIGS. 9B and 9D are Fourier diagrams of reticle patterns corresponding to FIGS. 9A and 9C, respectively. The figure explaining the arrangement of each fly-eye lens group (surface light source image) on the conversion surface,

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

[Explanation 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 diaphragm 12 ... Reticle 12b ... Phase shift reticle 13 ... Reticle pattern 14 ... Projection optical system 15 ... Pupillary surface 15a ... NA diaphragm 16 ... Wafer 19 ... Z stage 21 ... XY Stage 24 ... Reference member 25 ... Photoelectric detector 26, 27, 28, 29, 30, 31 ... Gap sensor AF 32 ... Focus control system 33 ... Main control system 34 ... Bar code reader 35 ... Keyboard 36, 37, 18, 29 , 30, 48, 49, 60 ... Driving system 40, 41 ... Light splitting member 42, 45, 46, 47 ... Holding member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03F 9/00 H 9122-2H

Claims (4)

[Claims] 1. An illumination optical system for irradiating a mask having a fine pattern with illumination light from a light source, a projection optical system for projecting and exposing a pattern image of the mask onto a substrate, and holding the substrate, A stage that is movable in the optical axis direction of the projection optical system, detects a relative position deviation between the predetermined image plane of the projection optical system and the substrate in the optical axis direction, and outputs a detection signal according to the deviation. A projection type exposure apparatus comprising: focus detection means; and control means for controlling movement of the stage based on the detection signal, wherein the numerical aperture of the projection optical system, the numerical aperture of the illumination optical system, and the projection Input means for inputting information about at least one of the shape of the light beam passing through the Fourier transform surface of the mask and the position of the light beam passing through the Fourier transform surface in the optical system;
Setting means for setting a predetermined exposure condition based on information from the input means; switching means for switching the exposure condition set in the setting means; light on the predetermined image formation plane that changes by switching by the switching means A projection type exposure apparatus comprising: an adjusting unit that adds an offset to either one of the focus detecting unit and the control unit by a value corresponding to a change in position in the axial direction. 2. The apparatus according to claim 1, wherein the exposure condition is an illumination condition. 3. The apparatus according to claim 1, wherein the exposure condition is a numerical aperture of the projection optical system. 4. The apparatus according to claim 1, wherein the exposure condition is a condition of the mask to be exposed.