JPH06120110A - Projection aligner and exposure method - Google Patents

Abstract

PURPOSE:To magnify the depth of focus at the time of projection exposure of a contact hole pattern. CONSTITUTION:On the pupil surface there is provided a polarizing plate, a 1/2 wavelength plate, a 1/4 wavelength plate, or an optically active material which makes the polarization state of an imagery light flux LFa different from the polarization state of an imagery light flux LFb. The flux LFa passes the central circular region of the pupil surface of a projection optical system PL. The flux LFb passes the ring belt type region around the central circular region. Thereby the SFINCS method of turning the two imagery light fluxes (LFa, LFb) into at least an incoherent state is applied.

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 used for forming fine patterns in semiconductor integrated circuits, liquid crystal displays and the like.

[0002]

2. Description of the Related Art A projection optical system used in a projection type exposure apparatus of this type is incorporated into the apparatus by advanced optical design, careful selection of glass materials, ultra-precision processing of glass materials, and precise assembly and adjustment. . Currently, in the semiconductor manufacturing process, the i-line (wavelength 365 nm) of a mercury lamp is used as illumination light for a reticle (mask).
A stepper that mainly irradiates the light and forms an image of the transmitted light of the circuit pattern on the reticle on a photosensitive substrate (wafer or the like) through a projection optical system is mainly used. An excimer stepper using an excimer laser (KrF laser having a wavelength of 248 nm) as illumination light is also used for evaluation or research. When the projection optical system for the excimer stepper is composed of only a refracting lens, usable glass materials are limited to quartz and fluorite.

Generally, in order to faithfully transfer a fine reticle pattern onto a photosensitive substrate by exposure using a projection optical system, the resolution and depth of focus (DOF: depth of focus) of the projection optical system are important factors. Has become.
Among the projection optical systems currently in practical use, those for the i-line having a numerical aperture (NA) of about 0.6 have been obtained. When the wavelengths of the illumination light used are the same, increasing the numerical aperture of the projection optical system improves the resolution accordingly. However, the depth of focus (DOF) decreases with increasing numerical aperture NA. The depth of focus is defined by DOF = ± λ / NA ² where λ is the wavelength of the illumination light.

FIG. 1 schematically shows an image forming optical path of a conventional projection optical system. The projection optical system is a lens system G of the front group.
A lens system GB of the rear group. This type of projection optical system is generally one in which both the reticle R side and the wafer W side are telecentric, or one in which only the wafer W side is telecentric. Now, in FIG. 1, three arbitrary points A, B, and C are assumed on the pattern surface of the reticle R (the object surface of the projection optical system). Rays L ₁ , L ₂ , L ₃ , La, L traveling from point A in various directions
a ', of the La ", light L ₁ occurs at an angle that can not enter the lens system GA of the projection optical system. Moreover, of the light incident on the lens system GA of the front group, ray L _2, L ₃
Is a pupil e located on the Fourier transform plane FTP in the projection optical system.
cannot pass p. And the other rays La, L
a ′ and La ″ pass through the pupil ep, enter the lens system GB of the rear group, and converge at the point A ′ on the surface of the wafer W (pupil surface of the projection optical system). Among the light rays generated from A, the light rays that have passed through the pupil ep of the projection optical system (a circular area centered on the optical axis AX) contribute to forming a point image at the point A ′. A ray La that passes through the center point CC (position of the optical axis AX) of the pupil ep among the rays directed to the point A ′ is called a principal ray, and this principal ray La is, in the case of a telecentric projection optical system on both sides, the object plane side, It is parallel to the optical axis AX in each space on the image plane side.

The same applies to the light rays generated from the other points B and C on the reticle R, and only the light rays passing through the pupil ep contribute to the formation of the point images B'and C '. Similarly, the light rays Lb and Lc that travel from the points B and C in parallel with the optical axis AX and enter the lens system GA are both chief rays passing through the center point CC of the pupil ep. In this way, the pupil ep has a Fourier transform and an inverse Fourier transform with respect to the pattern surface of the reticle R and the surface of the wafer W, and the light rays that contribute to image formation among the light rays from the pattern on the reticle are All the pupils ep will overlap and pass.

The numerical aperture of such a projection optical system is generally expressed as a value on the wafer side. In FIG. 1, among the rays that contribute to the formation of the point image A ′, the angles θw formed by the rays La ′ and La ″ passing through the outermost part in the pupil ep with the principal ray La on the wafer W are the projection optical system. Corresponding to the numerical aperture NA _W on the wafer (image plane) side, and is represented by NAw = sin θw Therefore, the angle θr formed by the light rays La ′ and La ″ with the principal ray La on the reticle R side is ) Side numerical aperture NAr, which is represented by NAr = sin θr. Further, the image forming magnification of the projection optical system is M (M for 1/5 reduction
= 0.2), NAr = M · NAw.

In order to increase the resolution, the numerical aperture NAw (NAr) must be increased. In other words, this means increasing the diameter of the pupil ep and further increasing the effective diameters of the lens systems GA and GB. It is nothing but making it bigger.
However, since the depth of focus DOF decreases in inverse proportion to the square of the numerical aperture NAw, even if a projection optical system with a high numerical aperture can be manufactured, the required depth of focus cannot be obtained. , Becomes a big obstacle in practical use.

When the wavelength of the illumination light is 365 nm of the i-line and the numerical aperture NAw is 0.6, the depth of focus DOF becomes about 1 μm (± 0.5 μm) in width, and one shot on the wafer W is obtained. In a region (20 mm square to 30 mm square), unevenness or curvature of the surface causes DOF or more in a portion having a DOF or more. Also on the stepper system, focusing for each shot area of the wafer W,
Since it becomes necessary to perform leveling and the like with extremely high accuracy, the load on the mechanical system, the electrical system, and the software (measurement resolution, servo control accuracy, setting time, etc.) will increase.

Therefore, the applicant of the present invention has solved such problems of the projection optical system, and has a high resolution and a large focus without using a phase shift reticle disclosed in Japanese Patent Publication No. 62-50811. A new projection exposure technique capable of obtaining both depth and depth is disclosed in JP-A-4-101.
It was proposed in Japanese Patent Laid-Open No. 148, Japanese Patent Laid-Open No. 4-225358 and the like. This exposure technique increases the apparent resolving power and the depth of focus by controlling the reticle illumination method to a special shape while maintaining the existing projection optical system.
HRINC (S uper H igh R esoluti
on by I llumi N ation C ontro
l) We call it the law. The SHRINC method irradiates the reticle with two illumination lights (or four illumination lights) symmetrically inclined in the pitch direction of the line and space pattern (L & S pattern) on the reticle R, and is generated from the L & S pattern. The 0th-order diffracted light component and one of the ± 1st-order diffracted light components are passed symmetrically with respect to the center point CC in the pupil ep of the projection optical system, and two-beam interference (interference between one 1st-order diffracted light and the 0th-order diffracted light) occurs. The principle is utilized to generate a projected image (interference fringe) of an L & S pattern.

According to the image formation utilizing the two-beam interference as described above, the occurrence of the wavefront aberration at the time of defocusing can be suppressed more than in the case of the conventional method (normal vertical illumination), so that the depth of focus apparently becomes large. Of. However, in the SHRINC method, the desired effect can be obtained when the pattern formed on the reticle R has a periodic structure like an L & S pattern (lattice). Can't get the effect.
In general, in the case of an isolated minute pattern, most of the diffracted light from it occurs as Franforfer diffraction, so that it is not clearly separated into zero-order diffracted light and higher-order diffracted light in the pupil ep of the projection optical system.

Therefore, as an exposure method for increasing the apparent depth of focus for an isolated pattern such as a contact hole, the exposure for one shot area of the wafer W is divided into a plurality of times, and the wafer W is subjected to the optical axis between the exposures. A method of moving a certain amount in a certain direction has been proposed, for example, in Japanese Patent Laid-Open No. 63-42122. This exposure method is FLEX ( F ocu
s L attitude enhancement EX
This is called the "posure) method, and a sufficient depth of focus expansion effect can be obtained for isolated patterns such as contact holes. However, since the FLEX method requires multiple exposure of a slightly defocused contact hole image, the sharpness of the resist image obtained after development is inevitably reduced. The problem of deterioration of sharpness (profile deterioration) is to use a resist with a high gamma value,
Multi-layer resist is used, or CEL (Contr
It can be compensated by using ast Enhancement Layer).

As an attempt to increase the depth of focus when projecting a contact hole pattern without moving the wafer W in the optical axis direction during the exposure operation as in the FLEX method, 1
991 Spring Applied Physics Society Proceedings 29a-ZC-8,
The Super-FLEX method announced in 9 is also known. This Super FLEX method uses the pupil e of the projection optical system.
A transparent phase plate is provided on p, and the phase plate has such a characteristic that the complex amplitude transmittance given to the image-forming light sequentially changes from the optical axis AX toward the periphery. By doing so, the image formed by the projection optical system maintains sharpness with a constant width (wider than before) around the best focus surface (the surface conjugate with the reticle R) in the optical axis direction. , The depth of focus increases.

[0013]

Among the various conventional techniques described above, the FLEX method and the Super FLEX method can obtain a sufficient depth of focus increasing effect for an isolated contact hole pattern. However, it has been found that in the case of a plurality of contact hole patterns that are close to each other to some extent, both methods cause an unnecessary film slip in the photoresist between the holes, which makes it practically difficult to use.

Further, in the FLEX method, even for an isolated contact hole pattern, the sharpness of the image (synthesized optical image obtained by multiple exposure) is inevitably deteriorated. There is also the problem that the degree decreases. Further, it is difficult to apply the scanning exposure type exposure apparatus by the FLEX method of the type in which the wafer is continuously moved or vibrated in the optical axis direction during the exposure work, and the exposure is divided into the first exposure and the second exposure. In the method in which the wafer is moved in the optical axis direction between the exposures, there is a problem that the processing capacity is largely reduced and the throughput is significantly reduced.

Therefore, the present invention has an object to obtain a projection exposure apparatus having an increased depth of focus when projecting and exposing isolated patterns such as contact holes, and particularly for a plurality of isolated patterns which are relatively close to each other. It is an object of the present invention to obtain a device that can obtain the effect of expanding the depth of focus.

[0016]

In order to solve the above problems, in the present invention, an illuminating means (1 to 1) for irradiating a mask (reticle R) on which a fine pattern is formed with illuminating light for exposure.
4) and a projection optical system (PL) for injecting the light generated from the pattern of the mask and projecting the image of the pattern onto the sensitive substrate (wafer W) by projection. A circular area (FA) which is arranged on the Fourier transform plane (FTP) in the image forming optical path between and or near the Fourier transform plane, and which is centered on the optical axis of the projection optical system on the Fourier transform plane or on the near plane. A polarization state control means (polarization state control member PCM) is provided to make the polarization states of the image forming light (LFa) distributed inside and the image forming light (LFb) distributed in the area (FB) outside thereof different from each other. I did it.

[0017]

In the present invention, a polarization state control member is provided on a surface in the projection optical system (hereinafter abbreviated as a pupil surface) which optically has a Fourier transform relationship with the reticle pattern surface, or a surface in the vicinity thereof. A part of the image-forming light distributed in a circular or annular shape in the pupil plane and a part of the image-forming light distributed in the other part are in a polarization state in which they do not interfere with each other. As a result, the exposure light beam (imaging light) that has been transmitted and diffracted in the reticle pattern, particularly through the contact hole pattern, is spatially divided into two light beams that do not interfere with each other in the pupil plane and reach the exposure target such as a wafer. To do. Even on the wafer, the two light beams do not interfere with each other (are incoherent), so that an intensity combined image of the images (contact hole images) produced by the respective light beams can be obtained. In the conventional exposure method, when the light beams that have passed through the minute contact hole pattern on the reticle and are diffracted reach the wafer surface through the projection optical system, they are all combined amplitude-wise (coherent addition) and the reticle pattern image (optical image ) Was formed. Conventional Super-
Even in the FLEX method, since the imaging light distributed on the pupil plane is only partially phase-shifted, it is still coherent addition.

Now, assuming that there is no phase shift plate or the like on the pupil plane of the projection optical system, the optical path length from any one point on the reticle to the corresponding image point on the wafer in best focus (in focus). Are the same regardless of which optical path in the projection optical system passes (Fermat's principle), so amplitude synthesis on the wafer is the synthesis of light with no phase difference,
All act in the direction of increasing the strength of the contact hole pattern.

However, when the wafer is defocused, the above optical path length becomes different depending on the optical line in the projection optical system. As a result, the above-mentioned amplitude composition is the optical path difference (phase difference).
The addition of the light having the above value causes a canceling effect in a part, and weakens the central strength of the contact hole pattern.
If the incident angle of an arbitrary ray incident on one image point on the wafer is θ and the optical path length of the ray (chief ray) incident vertically on the wafer is a reference (= 0), the optical path difference generated at this time is It is expressed as approximately 1/2 (ΔF · sin ² θ). Here, ΔF represents the defocus amount. Since the maximum value of sin θ is the numerical aperture NAw on the wafer side of the projection optical system, when all the light that has passed through the pupil ep among the diffracted light from the minute hole pattern is amplitude-combined on the wafer as in the conventional case, the maximum value is obtained. Will result in an optical path difference of 1/2 (ΔF · NAw ² ). At this time, assuming that an optical path difference of λ / 4 is allowed as the depth of focus, the following relationship holds.

1/2 (ΔF · NAw ² ) = λ / 4 When this equation is recombined, ΔF = λ / (2NAw ² ), which is in agreement with the generally-known depth of focus. For example, i-line (wavelength 0.3
65 μm), numerical aperture NAw = 0.50
Assuming that, the depth of focus ± ΔF / 2 is ± 0.73 μm, which is a value with almost no margin for a process step difference of 1 μm on the wafer.

On the other hand, in the present invention, as shown in FIG. 2, a polarization state control member PCM is provided on the pupil plane (FTP) of the projection optical system. At this time, an imaging light beam (the principal ray is LL) diffracted by the isolated pattern Pr formed on the pattern surface of the reticle R.
After entering the front lens group GA of the projection optical system PL, p) reaches the Fourier transform plane FTP. Then, in the Fourier transform plane FTP, the light fluxes transmitted through the central circular transmission portion FA and the annular transmission portion FB in the pupil plane ep are controlled (converted) into polarization states that do not interfere with each other. Therefore, on the wafer W, the light flux LFa transmitted through the circular transmissive portion FA of the polarization state control member PCM and the light flux LFb transmitted through the peripheral transmissive portion FB do not interfere with each other. As a result, the luminous flux LFa from the circular transmitting portion FA and the peripheral portion FB are
Light fluxes LFb from each other independently interfere with each other by themselves, and each has a hole pattern image (intensity distribution) P.
form r '. That is, an image obtained by the interference of only the light beam LFa and an image produced by the interference of only the light beam LFb is simply added in terms of intensity, and an isolated contact hole or the like obtained by the present invention is obtained. It becomes a pattern image Pr '.

The illumination light ILB to the reticle R has a constant numerical aperture sin ψ / 2 as in the conventional case. However, the numerical aperture NAr on the reticle side of the projection optical system PL is set to the condition NAr> sin ψ / 2. Therefore, the principle of image formation in the present invention will be described with reference to FIG. FIG. 3 schematically shows the relationship between the structure of the polarization state control member PCM, the state of the image forming light flux that forms the image Pr ′ of the contact hole, and the optical path difference ΔZ of each light flux during defocusing. is there.

Light flux LFa passing through the central portion as shown in FIG.
In amplitude combination within, since the light flux LFa includes the angle range from the vertically incident light (the principal ray LLp) to the incident angle θ ₁ ,
The maximum value ΔZ ₁ of the optical path difference when the defocus amount is ΔF is Δ
Z ₁ = 1/2 (ΔF · sin ² θ ₁ ). Incidentally, FIG.
The horizontal axis of the graph at the bottom represents the sine of the incident angle, sin
Let θ ₁ = NA ₁ . On the other hand, in amplitude combination in the light flux LFb passing through the peripheral portion as shown in FIG. 3B, since the light flux LFb has an incident angle range from the incident angle θ ₁ to the numerical aperture NAw (sin θw), the defocus amount is ΔF. The maximum optical path length difference ΔZ _{2 at that time} is ΔZ ₂ = 1/2 (ΔF) (NAw ²
−sin ² θ ₁ ).

Since the first light beam LFa and the second light beam LFb do not interfere with each other, the deterioration of the image Pr ' ₁ due to the interference of only the light beam LFa and the deterioration of the image Pr' ₂ due to the interference of only the light beam LFb are different. This is caused only by the optical path length differences ΔZ ₁ and ΔZ ₂ in the light flux. For example, setting the sin [theta ₁ as a _{^{sin 2 θ 1 = 1/2}} (NAw 2), i.e.

[0025]

[Equation 1]

The first transmissive portion F so that the relationship of
When the radius of A is set, the maximum optical path difference ΔZ ₁ due to the first light flux LFa and the maximum optical path difference ΔZ due to the second light flux LFb are set.
Each ₂ is as follows. ΔZ ₁ = 1/2 (ΔF · sin ² θ ₁ ) = 1/4 (ΔF · NAw ² ) ΔZ ₂ = 1/2 (ΔF) (NAw ² −sin ² θ ₁ ) = 1/4 (ΔF · NAw ² ) Thus, two incoherent light beams LFa and L
Each of the Fbs has substantially the same maximum optical path difference, 1/4 (ΔF · NAw ² ), when defocused by ΔF, and this value is half that in the conventional case. In other words, even if the defocus amount (2ΔF) is twice as large as the conventional one, the same maximum optical path length difference as in the case of the defocus amount ΔF in the conventional projection method will suffice, resulting in the isolated pattern Pr.
The depth of focus at the time of imaging is increased about twice. The pupil plane ep of the projection optical system PL, a method of exchanging a plurality of light beams do not interfere with imaging light beam from each other, thereafter SFINCS (S patial F ilter for
It will be referred to as INC oherent S tream) method.

[0027]

FIG. 4 shows the overall construction of a projection exposure apparatus according to an embodiment of the present invention. In FIG. 4, the high-intensity light emitted from the mercury lamp 1 is converged on the second focal point by the elliptical mirror 2 and then becomes divergent light and enters the collimator lens 4. A rotary shutter 3 is arranged at the position of the second focal point, and controls passage and blocking of illumination light. The illumination light converted into a substantially parallel light flux by the collimator lens 4 is
It is incident on the interference filter 5, where only the desired spectrum required for exposure, eg, the i-line, is extracted. The illumination light (i-line) emitted from the interference filter 5 passes through the polarization control member 6 for aligning the polarization direction, and then enters the fly-eye lens 7 as an optical integrator.
This polarization control member 6 may be omitted depending on the configuration of the polarization state control member PCM in the projection optical system PL and the nature of the light source, which will be described later. Further, the polarization control member 6
Is a polarizing plate because it simply aligns the illumination light incident on the fly-eye lens 7 in a certain polarization direction.

The illumination light (substantially parallel luminous flux) incident on the fly-eye lens 7 is divided by a plurality of lens elements of the fly-eye lens 7, and a secondary light source image (mercury) is provided on the exit side of each lens element. An image of the light emitting point of the lamp 1) is formed. Therefore, the same number of point light source images as the number of lens elements are distributed on the exit side of the fly-eye lens 7 to form a surface light source image. A variable diaphragm 8 for adjusting the size of the surface light source image is provided on the exit side of the fly-eye lens 7. Illumination light (divergent light) that has passed through the diaphragm 8 is reflected by a mirror 9 and enters a condenser lens system 10, and then illuminates the rectangular opening of the reticle blind 11 with a uniform illuminance distribution. In FIG. 4, of the plurality of secondary light source images (point light sources) formed on the exit side of the fly-eye lens 7, the optical axis A
Only illumination light from one secondary light source image located on X is representatively shown. Moreover, by the condenser lens system 10,
The exit side of the fly-eye lens 7 (the surface on which the secondary light source image is formed) is a Fourier transform surface for the rectangular aperture surface of the reticle blind 11. Therefore, fly eye lens 7
From each of the plurality of secondary light source images of the condenser lens system 1
The respective illumination lights that have entered 0 are superimposed on the reticle blind 11 as parallel light beams having slightly different incident angles.

The illumination light passing through the rectangular opening of the reticle blind 11 enters the condenser lens 14 via the lens system 12 and the mirror 13, and the light emitted from the condenser lens 14 reaches the reticle R as the illumination light ILB. Here, the rectangular opening surface of the reticle blind 11 and the pattern surface of the reticle R are arranged conjugate with each other by a composite system of the lens system 12 and the condenser lens 14,
The image of the rectangular opening of the reticle blind 11 is the reticle R
The image is formed so as to include a rectangular pattern formation region formed in the pattern surface of the. As shown in FIG. 4, the illumination light ILB from one secondary light source image located on the optical axis AX of the secondary light source image of the fly-eye lens 7 has an inclination with respect to the optical axis AX on the reticle R. There is no parallel light flux, but
This is because the reticle side of the projection optical system PL is telecentric. Of course, a large number of secondary light source images (off-axis point light sources) that are displaced from the optical axis AX are formed on the exit side of the fly-eye lens 7, so that any illumination light from them is on the reticle R. Then, it becomes a parallel light beam inclined with respect to the optical axis AX and is superimposed in the pattern formation region.
It goes without saying that the pattern surface of the reticle R and the exit side surface of the fly-eye lens 7 are optically Fourier-transformed by the combined system of the condenser lens system 10, the lens system 12, and the condenser lens 14. . Further, the incident angle range ψ of the illumination light ILB on the reticle R (see FIG. 2)
Varies depending on the aperture diameter of the diaphragm 8. When the aperture diameter of the diaphragm 8 is reduced to reduce the substantial area of the surface light source, the incident angle range ψ also decreases. Therefore, the diaphragm 8 adjusts the spatial coherency of the illumination light. As a factor representing the degree of spatial coherency, a ratio (σ value) between the sine of the maximum incident angle ψ / 2 of the illumination light ILB and the numerical aperture NAr of the projection optical system PL on the reticle side is used. This σ value is usually defined by σ = sin (ψ / 2) / NAr, and most steppers currently in operation have σ = 0.
It is used in the range of 5 to 0.7.

A predetermined reticle pattern is formed of a chrome layer on the pattern surface of the reticle R. Here, the chrome layer is vapor-deposited on the entire surface and a minute rectangular opening (transparent without the chrome layer is formed therein). It is assumed that there are a plurality of contact hole patterns formed in part).
The contact hole pattern may be designed to have a size of 0.5 μm square (or diameter) or less when projected onto the wafer W, and the projection magnification M of the projection optical system PL may be designed.
The dimensions on the reticle R are determined in consideration of the above. Further, since the dimension between adjacent contact hole patterns is usually considerably larger than the dimension of the opening of one contact hole pattern, it exists as an isolated minute pattern. That is, the two adjacent contact hole patterns are often separated to the extent that the light (diffracted and scattered light) generated from each of them does not strongly influence each other like a diffraction grating. However, as will be described later in detail, there is also a reticle in which contact hole patterns are formed in close proximity to each other.

In FIG. 4, the reticle R is held on the reticle stage RST, and the optical image (light intensity distribution) of the contact hole pattern of the reticle R is imaged on the photoresist layer on the surface of the wafer W via the projection optical system PL. To be done.
Here, the optical path from the reticle R to the wafer W in FIG. 4 is shown only by the chief ray of the imaging light flux. And the projection optical system P
The Fourier transform plane FTP in L is provided with the polarization state control member PCM described in FIGS. 2 and 3 above. The polarization state control member PCM has a diameter that covers the maximum diameter of the pupil ep, and can be moved out of the optical path or into the optical path by the slider mechanism 20. If the stepper is used exclusively to expose the contact hole pattern, the polarization state control member PCM
May be fixed in the projection optical system PL. However, when performing exposure work in a lithography process by a plurality of steppers, in consideration of the most efficient operation of each stepper, it is hesitant to assign one specific stepper to the exposure dedicated to the contact hole pattern. Therefore, the polarization state control member PCM has the projection optical system P
It is desirable that the stepper be provided so as to be insertable into and removable from the L pupil ep so that the stepper can be used even during exposure of a reticle pattern other than the contact hole pattern. still,
Depending on the projection optical system, its pupil position (Fourier transform plane F
(TP) may be provided with a circular aperture stop for changing the effective pupil diameter. In this case, the aperture stop and the polarization state control member PCM are arranged as close as possible without mechanical interference.

The wafer W moves two-dimensionally (hereinafter referred to as XY movement) in a plane perpendicular to the optical axis AX, and
The wafer is held on a wafer stage WST that is slightly moved (hereinafter, referred to as Z movement) in a direction parallel to the optical axis AX. The XY movement and the Z movement of the wafer stage WST are performed by the stage drive unit 22, the XY movement is controlled according to the coordinate measurement value by the laser interferometer 23, and the Z movement is set to the detection value of the focus sensor 24 for autofocus. It is controlled based on. Stage drive unit 2
2. The slider mechanism 20 and the like operate according to a command from the main control unit 25. This main control unit 25 further sends a command to the shutter drive unit 26, and the shutter 3
In addition to controlling the opening and closing of the aperture, a command is sent to the aperture control unit 27 to control the size of each aperture of the diaphragm 8 or the reticle blind 11. Further, the main control unit 25 can input the reticle name read by a bar code reader 28 provided in the reticle transport path to the reticle stage RST. Therefore, the main control unit 2
5 is a slider mechanism 20 according to the input reticle name.
And the operation of the aperture drive unit 27 are comprehensively controlled, and the aperture size of the diaphragm 8, the reticle blind 11, and the necessity / non-necessity of the polarization state control member PCM are automatically adjusted according to the reticle. be able to.

Here, the structure of a part of the projection optical system PL in FIG. 4 will be described with reference to FIG. FIG. 5 shows a partial cross section of the projection optical system PL, which is made entirely of a refractive glass material. The lowermost lens GA ₁ of the front lens group GA and the uppermost lens GB ₁ of the rear lens system GB are shown. The Fourier transform plane FTP exists in the space between and. Although the projection optical system PL holds a plurality of lenses by a lens barrel, the polarization state control member P
An opening is provided in a part of the lens barrel for inserting and removing the CM. Further, a cover 20B that does not directly expose the polarization state control member PCM and the slider mechanism 20 in whole or in part is extended from the opening of the lens barrel. This cover 2
0B prevents minute dust floating in the outside air from entering the pupil space of the projection optical system PL. An actuator 20A such as a rotary motor, a pen cylinder, and a solenoid is coupled to the slider mechanism 20. Further, a channel Af communicating with the pupil space is provided in a part of the lens barrel, and clean air whose temperature is controlled is supplied to the pupil space through the pipe 29, so that a part of the exposure light of the polarization state control member PCM is exposed. The temperature rise due to absorption and the temperature rise of the entire pupil space are suppressed. If the clean air forcibly supplied to the pupil space is forcibly discharged via the slider mechanism 20 and the actuator 20A, the slider mechanism 20
It is possible to prevent dust and dust generated due to such factors from entering the pupil space.

FIG. 6 shows the structure of the polarization state controlling member PCM according to the first embodiment, and FIG. 6 (A) is a sectional view.
(B) is a plan view. As described above with reference to FIG. 3, the radius r _{1 of the} circular transmitting portion FA that gives the first polarization state
Is the effective maximum radius r ₂ of the pupil ep,

[0035]

[Equation 2]

Although it is set to, it is better to be several percent larger than that. As is clear from this equation, the area πr ₁ ² of the circular transmission part FA is approximately half the area πr ₂ ² of the effective pupil aperture. Now, the light source (mercury lamp 1) in FIG. 4 generates light of random polarization state (light that is a combination of light of various polarization states, and that polarization state changes with time). In the first embodiment of the present invention, since the linear polarization plate is used as the polarization state control member PCM of FIG. 6, the polarization control member 6 in FIG. 4 is omitted. In that case, the polarization state of the light flux that passes through the contact hole pattern on the reticle and reaches the polarization state control member PCM is also random. The polarization state control member PCM shown in FIG. 6 is configured by a polarizing plate that transmits only linearly polarized light in a specific direction in the circular transmission part FA having a radius r ₁ from the center point CC, and has a ring-shaped periphery coaxial with the center point CC. The transmissive part FB is composed of a polarizing plate that transmits only linearly polarized light in a direction orthogonal to the circular transmissive part FA. Therefore, the polarization state of the imaging light flux after passing through the polarization state control member PCM of FIG.
As shown in (c), the central transmission part FA has, for example, a vibration plane (polarization plane) of the electric field from the upper right to the upper left in the figure, and the peripheral transmission part FB has a polarization plane from the upper left to the lower right, which are orthogonal to each other. Light beams (LFa, LFb) that do not interfere with each other. Both the central and peripheral light beams that do not interfere with each other are transferred to the wafer W.
And each of them amplitude-combines only with itself and separately creates images (intensity distribution) Pr ₁ 'and Pr ₂ ', the principle of increasing the depth of focus of the combined image (composite intensity distribution) is As described in section.

FIG. 7 shows the structure of the polarization state control member PCM according to the second embodiment. In the present embodiment, as in the case of FIG. 6, the central circular transmissive portion FA and the peripheral annular transmissive portion FB are the same in that they are polarizing plates that pass only linearly polarized light in polarization directions orthogonal to each other. The difference is that a quarter wave plate FC is further provided on the entire exit side. In the axial direction of the quarter-wave plate FC (the direction in which the crystal has a high refractive index with respect to the incident light beam), the linearly polarized light transmitted through the circular transmissive portion FA and the linearly polarized light transmitted through the annular transmissive portion FB are opposite to each other. Of (left
Right) This is the axial direction for exchanging circularly polarized light. Where 1 /
The wavelength of the four-wave plate FC is, of course, the wavelength λ of the exposure light. A birefringent material such as quartz is used as the material of the quarter-wave plate FC. Now, the polarization state of the imaging light flux transmitted through the polarization state control member PCM shown in FIGS. 7A and 7B is as shown in FIG.
As shown in (C), for example, right-handed circularly polarized light is obtained at the transmissive portion FA, and left-handed circularly polarized light is obtained at the peripheral transmissive portion FB, so that they are in a polarization state where they do not interfere with each other. As a matter of course, in this circularly polarized state, the rotation directions of the quarter-wave plate FC and the polarizing plates FA and FB are determined so that the transmitted light of the central transmission portion FA is counterclockwise and the transmitted light of the peripheral transmission portion FB is clockwise. May be.

In the first and second embodiments described above, since the polarization state control member PCM in the projection optical system PL is composed of a polarizing plate, half of the original amount of light to be transmitted through the projection optical system PL is used. Will be absorbed by the polarizing plate as the polarization state control member PCM. This also means a decrease in exposure power, but heat (energy of the absorbed exposure light) accumulates in the projection optical system, which poses a problem in terms of the stability of the optical system and the glass material.

An embodiment for solving this heat problem (exposure power loss) will be described with reference to FIGS. In the present embodiment, the polarization characteristic of the illumination light ILB is important, so that will be described first. FIG. 8 shows some examples of the polarization control member 6 provided in the illumination optical system. FIG. 8A is an example in which a polarizing plate 6A is used as the polarization control member 6, and incident light from the mercury lamp 1 that is random polarized light is emitted as specific linearly polarized light. FIG. 8B shows an example in which a polarization plate 6A and a quarter-wave plate 6B are combined as the polarization control member 6.
Also at this time, the incident light which is randomly polarized light is reflected by the polarizing plate 6A.
First, the light is converted into linearly polarized light by the ¼ wavelength plate 6B, and then the light is emitted as either right-handed or left-handed circularly polarized light. Also at this time, the axial direction of the quarter-wave plate 6B is set to the axial direction for converting the linearly polarized light from the polarizing plate 6A into circularly polarized light. Also, the luminous flux (incident luminous flux) itself from the light source
In the case of linearly polarized light, for example, when a laser light source is used, the illumination light ILB reaching the reticle R is the polarization control member 6
Is linearly polarized light even if it is not provided. However,
Depending on the configuration of the polarization state control member in the projection optical system, which will be described later, as shown in FIG. 8 (C), it is preferable to provide only the ¼ wavelength plate 6B as the polarization control member 6 and make it circularly polarized. The axial direction of the quarter-wave plate 6B in this case is also set as described above.

Now, if the polarization characteristics of the illumination light ILB to the reticle R are made uniform by using the polarization control member 6 as shown in FIG. 8, the projection optical system PL is transmitted through the contact hole pattern and diffracted. The image-forming light flux reaching the inside polarization state control member PCM is also in a state of being aligned with a specific linearly polarized light or circularly polarized light. Therefore, FIG. 9 shows a structure of the polarization state control member PCM suitable for the case where the illumination light ILB is linearly polarized, as a third embodiment. FIG. 9A shows an example in which a ½ wavelength plate is used as the polarization state control member PCM. Figure 9
(A) shows the polarization state of the light immediately before entering the polarization state control member PCM, and here it is assumed to be linearly polarized light having an electric field vibration plane in the vertical direction in the figure. Figure 9 (B) shows the plane structure of the polarized state control member PCM, circular transmitting portion FA ₁ of radius r ₁ is constituted by a half-wave plate, annular transmitting portion FA ₂ near the transmissive portion FA ₁ ( It is an ordinary transparent plate (for example, quartz) having a thickness (optical thickness) almost equal to that of the ½ wavelength plate. As shown in FIG. 9C, the polarization state of the light immediately after passing through the polarization state control member PCM of FIG. 9 is converted from the partial polarization state of the circular transmissive portion FA ₁ into the linearly polarized light in the left-right direction, and the peripheral ring. The polarization state does not change at all in the band-shaped transmission portion FA ₂ . Therefore, similarly to the first embodiment, it is possible to obtain a polarization state in which the central portion and the peripheral portion of the image-forming light beam do not interfere with each other. Here, the transmission part FA
The axial direction (in-plane rotation) of the half-wave plate as ₁ is set to the axial direction that converts the direction of the incident linearly polarized light into the direction orthogonal to it, but the axial direction of the half-wave plate is In order to optimize the polarization direction of the illumination light ILB, the polarization state control member PCM and the polarization control member 6 may be in-plane relatively adjustable in the rotation direction.

On the other hand, FIG. 10B shows the polarization state control member P.
Radius r as CM₁Circular transparent part FA₂And surrounding zones
Transparent part FB₂And 1/4 wave plate (same thickness)
It is the fourth embodiment. Even in this case, the incident light flux is
Since all of them are linearly polarized light like 10 (A), each transmission part FA
₂, FB₂Of the incident light flux along the axial direction of the 1/4 wavelength plate of
By optimizing for each condition, it is shown in FIG.
Circular transmission part FA ₂The light flux passing through the
For light, the annular transmission part FB₂The light flux that has passed through is a counterclockwise circle
It can be converted into polarized light and has different polarization states (interfering with each other).
Light flux (LFa, LFb) can be obtained. This
Also in the case of the fourth embodiment, the polarization state is the same as in the third embodiment.
Align with the axial direction of the quarter-wave plate as the state control member PCM
Then, the polarization direction of the illumination light ILB is controlled by the polarization control member 6.
It is good to be able to adjust. Shown in FIG. 9 (B)
Round transparent part FA₁As a half-wave plate, a crystal, etc.
The optical rotatory substance of
The direction of linearly polarized light can be changed.

FIG. 11 shows a case of the circularly polarized illumination light ILB.
And showing a preferred polarization state control member PCM
This is an example. This fifth embodiment is basically the same as the previous one.
The same as the polarization state control member PCM of the third embodiment (FIG. 9)
To use. Therefore, as shown in FIG.
₁Circularly polarized state of transmitted light only by constructing half wave plate
Can be reversed as shown in FIG. Lap
Ring-shaped transparent part FB on the side ₁Is the transmission part FA₁1/2 wave plate
It is a transparent object (such as a quartz plate) having a thickness similar to that of. The figure
In the case of 11 (B) as well, as in the case of FIG. 9 (B)
Transparent part FB₁Alternatively, it may be configured with a half-wave plate.

FIG. 12 shows the configuration of the polarization state control member PCM according to the sixth preferred embodiment for the circularly polarized illumination light ILB, which may be exactly the same as the case of FIG.
That is, the circular transmission portion FA ₂ and the ring-shaped transmission portion FB ₂ are each formed of a quarter wavelength plate, and the quarter wavelength plates are adjusted and combined so that their axial directions are orthogonal to each other.
In the case of FIG. 12, the transmitted light of each of the transmission parts FA ₂ and FB ₂ becomes linearly polarized light which is orthogonal to each other as shown in FIG.

As described above, when the incident light flux (illumination light ILB) is circularly polarized light as shown in FIGS.
This is convenient because there is no need to rotate and adjust the axial direction of the / 4 wave plate according to the polarization characteristics of the illumination light. As described above, when the polarization control member 6 shown in FIG. 8 and the polarization state control member PCM shown in each of FIGS. 9 to 12 are used, absorption of exposure energy in the polarization state control member PCM as described above is performed. This is extremely convenient in that the problem of 1 is eliminated and heat accumulation in the projection optical system PL is suppressed. However, this time, the light amount loss (more than half) accompanying the alignment of the illumination light ILB into one polarization state in the illumination optical system remains a problem. Therefore, an example of the illumination system in which the light amount loss of the illumination light is reduced will be described as a seventh embodiment with reference to FIG. The system of FIG. 13 is provided instead of the polarization control member 6 of FIG. First, in FIG. 13A, the incident light beam is split by the two polarization beam splitters 6C and 6D,
Is synthesized. That is, the first polarization beam splitter 6C transmits the P-polarized component (polarized light in the vertical direction) and
The second polarization beam splitter 6D is also transmitted and goes straight. On the other hand, the S-polarized light component (polarized light in the direction perpendicular to the paper surface) split by the beam splitter 6C is combined by the beam splitter 6D via the mirrors 6E and 6F and travels coaxially with the P-polarized light component. At this time, an optical path difference of 2 × d ₁ is given to the P-polarized light and the S-polarized light by the optical paths of the mirrors 6E and 6F. Therefore, the temporal coherence length ΔLc of the incident light beam is 2
If it is shorter than d ₁ , the combined P-polarized component and S-polarized component become incoherent (non-coherent) in terms of time, in addition to having complementary polarization directions. Illumination light having these two polarization components is used, and the polarization state control member PCM
9 is used as shown in FIG. 14, the P-polarized component (for example, the white arrow direction) and the S-polarized component (for example, the black arrow direction) are incident on the polarization state control member PCM, respectively. After passing through the polarization state control member PCM as shown in FIG. 14C, there are four light beams which do not interfere with each other. That is, the original polarization direction is rotated by 90 ° in the circular transmission part FA ₁ (1/2 wavelength plate). The four light beams have different polarization directions, and even if the transmission parts FA ₁ and FB ₁ have the same polarization direction, they do not interfere with each other because they are temporally incoherent. That is, the S-polarized component that has passed through the transmissive portion FA ₁ is converted into a P-polarized component and has the same polarization direction as the P-polarized component that has transmitted through the transmissive portion FB ₁ , but the two lights are temporally incoherent. So do not interfere. If Figure 1
If the illumination light from the polarization control member having the configuration as shown in FIG. 3 (A) is not used, the P-polarized light and the S-polarized light in FIG. 14 remain coherent in time, and therefore, after passing through the polarization state control member PCM. If the respective light fluxes have the same polarization direction, they will interfere with each other, and the effect of the present invention will be weakened. FIG.
The system shown in (A) can make a large difference in optical path length between two polarization components to be combined, and is therefore suitable for a light source having a relatively long temporal coherence length, for example, a laser light source with a narrow band.

When linearly polarized light is used as the laser light source, the effect of the present invention can be obtained without using the polarization control means having the structure shown in FIG. However, when the polarization control means as shown in FIG. 13A is used for a linearly polarized laser light source, the illumination light can be made into two temporally incoherent light beams, which is a problem when using the laser light source. Speckle and interference fringes (irregularity of illuminance)
Is effective. in this case,
The polarization direction of the linearly polarized light incident on the first-stage beam splitter 6C in FIG.
As shown in FIG. 13A with respect to C, the P polarization direction and S
Polarization direction L intermediate to the polarization direction (45 ° direction from both)
PL is recommended.

By the way, when the light source is a light source having a comparatively large spectral width such as a mercury lamp, its temporal coherence length is short. Therefore, a simple member as shown in FIG. It can be used as the control member 6. This member is a transparent parallel plate 6G made of quartz or the like with a polarizing reflection film 6H attached to the surface thereof, and a total reflection film 6J made of metal or the like on the back surface thereof so that the collimated light flux from the mercury lamp is reflected at a predetermined angle. Is located in. At this time, of the randomly polarized incident light from the mercury lamp, the S-polarized component (direction perpendicular to the paper surface) is reflected by the film 6H on the surface, and P
The polarization component is transmitted through the film 6H on the front surface and the parallel plate 6G and is reflected by the film 6J on the back surface, and the S polarization component and the P polarization component are almost twice the thickness (optical thickness) of the parallel plate 6G. The optical path difference corresponding to is given.

For example, in the case of i-line from a mercury lamp, the center wavelength λ is 365 nm and the wavelength width Δλ is about 5 nm.
A commonly used formula for coherent length, ΔLc = λ ² / Δ
From λ, the coherent length ΔLc is about 26 μm.
Therefore, a sufficiently thin parallel plate 6G (for example, about 1 mm thick)
Even in this case, it is possible to provide a sufficient optical path length difference to eliminate the temporal coherence.

Next, as shown in FIG.
(B) Polarization control means and polarization state control member PCM of FIG.
An eighth embodiment in which and are combined will be described with reference to FIG. In this embodiment, a quarter wavelength plate is provided on the exit side of the system shown in FIG.
As shown in (A), they are converted into circularly polarized light in mutually opposite directions. At this time, the light flux after passing through the polarization state control member PCM is as shown in FIG. 15C, and similarly there are four light fluxes that do not interfere with each other. In FIG. 15C, for example, the left-handed polarization component (white arrow) passing through the transmitting portion FA ₁ and the left-hand polarization component (black arrow) passing through the transmitting portion FB ₁ are temporally incoherent. Therefore, they do not interfere with each other.

FIG. 16 shows a ninth polarization state control member PCM.
The structure according to the embodiment is shown, and the central circular transmission part FA₁Toso
FB around the zone immediately in the vicinity₂And further around
Zone transparent part FB₃It has a triple structure with. Yen here
Shape transmission part FA₁And outermost ring zone transparent part FB₃Is the same polarization
It is a polarizing plate that transmits the state, and the intermediate zone transparent part FB ₂
Is a polarizing plate that passes the polarization state orthogonal to them,
The direction is as shown in FIG. The middle ring here
Band transmission part FB₂Transmitted light and circular transmission part FB₁With transmitted light
The principle that the depth of focus is increased by the luminous flux created by
As it is, circular transmission part FA₁And outermost ring zone transparent part FB₃
The transmitted light flux of is the same polarization state, and the incident angle on the wafer W is
Wide range of degrees from sin θ = 0 (normal incidence) to NAw
It is within the range. However, the circular transmission part FA₁
And zone transparent part FB₃Is a kind of triple focus filter
Therefore, a large depth of focus can be obtained. That
About the triple focus filter, January 23, 1964
Issued with. Mechanical Testing Laboratory Report No. 40
On imaging performance and its improving method "
It is described in detail on pages 41 to 55 of the paper.

FIG. 17 shows the polarization state control member PCM of FIG.
The circular transmission part FA ₁ and the outermost ring zone transmission part FB ₃ are polarizing plates that pass the same polarization component, and the middle ring zone transmission part FB ₂ has a polarization component in the direction orthogonal to them. It is a polarizing plate that passes through. However, in the circular transparent portion FA ₁ ,
As shown in (A), there is further provided a phase plate (phase film) FC ₂ that shifts the optical path length difference by 1/2 wavelength with respect to the transmitted light of the outermost ring zone transmission portion FB ₃ . As a result, by inverting the phase (amplitude) of each transmitted light of the circular transmission part FA ₁ and the outermost annular transmission part FB ₃ , a double focus filter is formed in that part, and the effect of increasing the depth of focus is achieved. Is obtained. Of course, the light flux from the intermediate ring-shaped transmission portion FB ₂ also contributes to the increase in the depth of focus because the incident angle range on the wafer W is narrow. Incidentally, the transmissive portions FA ₁ and F ₁ shown in FIGS.
The maximum effect can be obtained by determining the diameters of B ₂ and FB ₃ so that they are almost equal in area. This means that the optical path length difference ΔZ shown in FIG. 3 is converted into the transmission parts FA ₁ , FB ₂ , F.
This means that the light fluxes of B ₃ are approximately equally divided.

Now, FIG. 18 shows a tenth embodiment of the polarization state control member PCM, which is a double annular zone transmission part FA and FB.
And a circular light shielding portion FD ₁ is further provided at the center. At this time, the incident angle range of the image forming light flux on the wafer W is as shown in FIG. 18 when the radius of the light shielding portion FD ₁ is K ₁ .
As shown in (C), it is limited to two light fluxes from sin θ _K1 to NAw (each transmitted light of the transmission parts FA and FB). At this time, considering the light-shielding portion FD ₁ , the image forming light beam existing within the incident angle range NAw is divided into three, and the angle range of one light beam (optical path length difference ΔZ due to defocus) is also divided into three. As a result, the optical path difference that adversely affects the defocus is reduced. As a result, the depth of focus can be further expanded.

In FIG. 19, the relationship between the transmissive portion FA and the light shielding portion FD ₁ shown in FIG. 18 is reversed, and a ring-shaped light shielding portion FD ₂ is provided. At this time, the width of the light shielding portion FD ₂ is K ₂ −K ₁
And as shown in FIG. 19C, the incident angle range θ _K2 −
A part of the imaging light flux is shielded during θ _K1 . In the case of FIG. 19 as well, the same effect as in the case of FIG. 18 is obtained. By the way, in the polarization state control member PCM shown in FIGS. 16 to 19, the central circular transmission part or the ring-shaped transmission part is a polarizing plate, but as shown in FIGS. A wave plate or an optical rotatory substance may be used. The light-shielding portions FD ₁ and FD _{2 in} FIGS. 18 and 19 may be, for example, light-shielding films obtained by vapor-depositing a metal film or the like on a polarizing plate or a wave plate. It may be a plate or the like.

Further, since the light-shielding portions FD ₁ and FD ₂ or the light-shielding plate equivalent to the light-shielding portions FD ₁ and FD ₂ need to shield only the exposure wavelength, an optical sharp cut filter or the like made of a dielectric thin film or the like is used. It may be one that absorbs a short wavelength region such as ultraviolet light. This way,
For example, when an alignment mark on the wafer W is irradiated with a He-Ne laser as a light source, and a reflected light or the like is detected through the projection optical system PL, a TTL type alignment system is used, and the light shielding portion FD ₁ located on the pupil plane is used. , FD ₂ , or the light shielding plate has no adverse effect on the reflected light from the mark (light shielding). Alternatively, the light-shielding plate made of the above-mentioned metal or the light-shielding portions FD ₁ and FD ₂ through which the laser beam for illuminating the wafer mark or the light reflected from the mark may be used as the transmission region, and if the area is small, the effect of the present invention is obtained. Is not particularly detrimental.

FIG. 20 shows the TTL as the eleventh embodiment.
An example of the alignment system is shown, and a lattice mark is formed on the wafer W.
GR is formed, and the position of this mark GR in the lattice pitch direction is
Misalignment shall be detected. Here, FIG. 20 (A) is a paper
From the direction where the horizontal direction on the surface is the pitch direction,
Fig. 20 (B) is a view of the element system.
The system is viewed from the direction rotated by 90 °. Retik
Objective lens of the alignment optical system provided above the lens R
Coherent laser beam (He-N
e) ALB₁, ALB₂Are reflected by the mirror MR.
After crossing on the plane CF, open the window RM around the reticle R
The light enters the projection optical system PL via. First, in FIG. 20 (A)
As shown, 2 beam ALB₁, ALB₂In my eyes
Bending flexibility formed on the positioned polarization state control member PCM
Positive element PG₁, PG₂Incident on each of the
Two beams AL with an amount corresponding to the axial chromatic aberration of system PL
B ₁, ALB₂Change the direction of travel. Two by this
Beam ALB₁, ALB ₂Is the lattice mark on the wafer W
GR is an angle that is symmetrically inclined with respect to the pitch direction.
Irradiate. At this time, the pitch Pg of the grid mark GR,
Home ALB₁, ALB₂Wavelength λa and beam ALB
₁, ALB₂Incident angle θa is sin θa = λa / Pg
If the beam meets ALB₁Irradiation by the grid
+ 1st order diffracted light generated from mark GR and beam ALB
₂-First-order diffracted light generated from mark GR by irradiation of
Is the two beams ALB as shown in FIG.₁, A
LB₂Interfering beam AD with coaxial optical path
Go backwards as L. This interference beam ADL is polarization state controlled.
Flexibility correction element PG formed on the control member PCM₃Progress in
You can change the direction and go through the window RM of the reticle R
Return to the optical system. At this time, FIG. 20 (B)
As also shown in FIG.
Beam ALB₁, ALB₂Is the direction orthogonal to the pitch direction
Interference beam because it is inclined with respect to (non-measurement direction)
ADL also occurs with an inclination. Also shown in FIG. 20 (A).
Two beam ALB₁, ALB₂Cross at face CF
However, in reality, the surface CF should be aligned with the position of the window RM.
You can Ie two beams ALB₁, AL
B₂Compensates for axial chromatic aberration caused by
be able to. Furthermore, as shown in FIG.
Mu ALB₁, ALB₂Telecentric for non-measurement direction
By making it enter the window RM by shifting from the ricky condition
Therefore, it is possible to compensate for the chromatic aberration of magnification. The objective
The optical axis AXa of the lens OBJ is perpendicular to the reticle R.
Is set.

When measuring the positional deviation of the mark GR,
There are two ways. One of them is two beam AL
B₁, ALB₂Is formed on the mark GR by the intersection of
Position of the mark GR in the pitch direction based on the interference fringes
This is to detect this. For that, alignment
The returned interference beam ADL is photoelectrically detected in the optical system.
Equipped with a photoelectric sensor and measure the output signal level
Yes. One way to have two beams ALB₁, ALB
₂A slight frequency difference between the two (eg 20-100 KHz
Degree) to determine the interference fringes generated on the mark GR.
It is a heterodyne method that runs at a speed according to the frequency difference.
It In this case, two beam ALB₁, ALB ₂Frequency
Create a reference AC signal with a number difference and output from the photoelectric sensor.
Force signal (for heterodyne, the interfering beam ADL is
Since the intensity changes at the frequency, it becomes an AC signal)
By calculating the phase difference between the
Can be measured.

As described above, when the bending correction elements PG ₁ , PG ₂ , and PG ₃ for compensating for chromatic aberration are provided on the pupil plane of the projection optical system PL, depending on their arrangement, the light shielding portion FD shown in FIGS. ₁ , the shape of FD ₂ (or the light shielding plate) may interfere with the position. However, since the beams ALB ₁ , ALB ₂ or the interference beam ADL of this kind of alignment method have an extremely small spot diameter,
The respective dimensions of the correction elements PG ₁ , PG ₂ , PG ₃ may also be very small. Usually, the correction elements PG _{1 to} PG ₃ are formed as a phase grating on the surface of a transparent glass material by etching or the like. Therefore, as described above, the light shielding portion F
When D ₁ and FD ₂ interfere with each other in position, only the light shielding portion at that position needs to be a transparent portion.

Further, in FIG. 20, the correction elements PG _{1 to} PG _{3 are}
Is shown to be formed directly on the polarization state control member PCM, a normal quartz plate on which the correction elements PG _{1 to} PG ₃ are formed is fixedly arranged on the pupil plane, and the polarization state control member PCM uses the quartz plate. It may be arranged so that it can be inserted and removed in the immediate vicinity of. Incidentally, a method of providing a correction lens (convex lens) having a small diameter in the center of the pupil plane of the projection optical system PL and thereby compensating for the chromatic aberration of the alignment beam is disclosed in US Pat.
P. 5,100,237. in this case,
When a dichroic film having a low transmittance for the exposure wavelength and an extremely high transmittance for the wavelength of the alignment beam is vapor-deposited on the portion of the correction lens, the center light-shielding portion FD _{1 of} the polarization state control member PCM shown in FIG. Substantially equivalent ones can be easily constructed. However, the above USP.
5, 100 and 237, the transmissive part FA as shown in FIG.
There is no suggestion of providing FB at the same time.

Further, in the drive unit 22 of wafer stage WST shown in FIG. 4, the function of the conventional FLEX method may be provided in the control for finely moving wafer W in the optical axis direction. The combined use of the FLEX method can dramatically increase the effect of increasing the depth of focus according to the present invention. The present invention can be applied to any type of projection type exposure apparatus. For example, it may be a stepper type using a projection lens, a step-and-scan type using a catadioptric system, or a 1: 1 mirror projection type. In particular, in the scan type (step and scan) and mirror projection methods, it is said that it is difficult to apply the conventional FLEX method because the reticle and the wafer are exposed by scanning while moving in a plane perpendicular to the optical axis of the projection optical system. However, the present invention has an advantage that it can be applied to such a scanning type exposure apparatus very easily.

Therefore, a case where the present invention is applied to a mirror projection type aligner of equal magnification is explained as a twelfth embodiment with reference to FIGS. In FIG. 21, the illumination light from the mercury lamp (Xe-Hg) lamp 1 is projected on the reticle (mask) R through the illumination optical system ILS into an arc slit-shaped illumination area. The reticle R is held on the reticle stage RST capable of one-dimensional scanning,
It moves at the same speed in synchronization with wafer stage WST.
The projection optical system has a reflective surface MR on each of the reticle side and the wafer side.
₁ , a trapezoidal optical block having MR ₄ , a large concave mirror MR ₂ and a small convex mirror MR _3, and a concave mirror M with respect to the radius of curvature of the convex mirror MR _3.
The radius of curvature of R ₂ is set to about twice. This FIG.
In the case of such a system, the surface of the convex mirror MR _{3 is} the Fourier transform surface F with respect to the reticle pattern surface (or wafer surface).
Often matches TP.

At this time, the imaging light flux generated from the point Pr on the reticle R is reflected along the principal ray LLP by the reflecting surfaces MR ₁ ,
Proceed in the order of the upper side of the concave mirror MR ₂ , the entire surface of the convex mirror MR ₃ , the lower side of the concave mirror MR ₂ , and the reflecting surface MR ₄ ,
It converges on the point Pr ′ on the wafer W. Thus, even when the surface of the convex mirror MR ₃ is the pupil plane of the system, the polarization state control member PC used in each of the embodiments described above is used.
M can be used as it is or with a slight modification.

[0061] Specifically, it is located very close to the polarization state control member PCM convex mirror MR ₃ as shown in FIG. 22, and when the concave mirror MR ₂ comes incident on the convex mirror MR _3, convex mirror MR ₃ The polarization state of the image-forming light beam may be controlled by two (reciprocal) optical paths from when the light is emitted to the concave mirror MR ₂ . However, as shown in FIG. 6, FIG. 16, FIG. 18, and FIG. 19, each of the central circular (or annular zone) transmissive portion FA and the peripheral annular zone transmissive portion FB is simply composed of a polarizing plate. When it is present, it can be used as it is, but it is not possible to use 1/2 as part of the transmissive areas FA and FB.
When using the configuration of FIG. 7, FIG. 9 to FIG. 12, and FIG. 17 using a wave plate or a quarter wave plate, a half wavelength is taken into consideration in consideration of receiving a double polarization effect in the round-trip optical path. It is necessary to change the plate to a 1/4 wavelength plate and the 1/4 wavelength plate to a 1/8 wavelength plate.

In a projection exposure apparatus using an excimer laser as a light source, a secondary light source surface (a large number of point light sources) formed on the exit side of a fly-eye lens or the like is re-imaged on the pupil plane of the projection optical system. Therefore, an optical element (lens, reflecting surface,
Arrangement of an aperture stop, PCM, etc.) may cause the optical element to deteriorate due to a converged light source image after long-term use. Therefore, it is preferable that the polarization state control members PCM and the like are not strictly arranged on the pupil plane, but rather are slightly displaced.

In each of the above embodiments, the polarization control member 6 shown in FIG. 4 is provided in the illumination optical system. However, the polarization control member 6 reaches just before reaching the polarization state control member PCM in the projection optical system PL. It may be placed anywhere in the optical path of.
For example, a linearly polarized laser is used as a light source, and a quarter wavelength plate as a polarization control member 6 is used as a reticle R and a projection optical system PL.
, And the entire imaging light flux generated from the reticle R may be converted into circularly polarized light.

By the way, since the lens and the reflecting surface of the projection optical system used in this type of exposure apparatus are made of an extremely uniform glass material, the polarization direction of the light beam entering the projection optical system and the polarization direction of the light beam exiting the projection optical system. They should agree well with each other, but slight deviations can occur. in this case,
Even if the polarization state control member PCM is ideally arranged, the polarization directions of the two light beams LFa and LFb are not completely complementary. However, since the deviation from the complementary relationship is only a slight amount, the effect of the present invention is not greatly impaired.

Next, the operation and effect obtained by each embodiment of the present invention will be described based on the simulation result. FIG. 23 (A) is a square contact hole pattern PA having one side corresponding to 0.3 μm on the wafer used in the following simulation. In the following simulation, the section AA ′ in FIG. 23 (A) is used. Image intensity distribution on the wafer. FIG. 23B is the same as FIG.
The ratio r of the shows the polarized state control member PCM, the maximum radius r ₂ of a radius r ₁ and the pupil of the circular transmitting portion FA in the center as shown in
₁ / r ₂ is NA ₁ / as described in the explanation of the principle.
It is set so that NAw = 0.707. That is, the maximum incident angle of the imaging light flux passing through the transmitting portion FA is set to θ ₁
Then, it is determined that sin ² θ ₁ = 1/2 (NAw ² ) is satisfied. In the following simulations, all NAw = 0.57, the exposure wavelength is i-line (wavelength 0.
(365 μm). The σ value, which is the coherence factor of the illumination light flux, was set to 0.6.
23 (C), (D), and (E) show image intensity distributions on the wafer of the pattern PA, which are the intensity distribution I ₁ at the best focus position and the intensity distribution I ₂ at the defocus position of 1 μm, respectively. It is the intensity distribution I ₃ at the defocus position of 2 μm. Further, Eth in FIGS. 23C, 23D, and 23E shows the strength required to completely remove (photosensitize) the positive photoresist on the wafer, and Ec dissolves the positive resist (film verification). Indicates the strength at which to start. The vertical magnification (exposure amount) of each intensity distribution is such that the contact hole diameter (width of the slice portion that crosses Eth) at best focus is 0.
It was set to be 3 μm. FIG. 24 for comparison
In (A), (B), and (C), the intensity distribution I ₇ at the best focus position and the intensity distribution I ₈ at the defocus position of 1 μm by the normal exposure apparatus (without the control member PCM) are 2 μm. The intensity distribution I ₉ at the defocus position of is shown. The simulation conditions at this time are also NAw = 0.57, wavelength λ = 0.365 μm, σ =
It is 0.6.

24A to 24C and the previous FIG. 23.
Comparing (D) to (F), it can be seen that the change in image intensity (decrease in contrast) during defocus is reduced and the depth of focus is increased. On the other hand, FIG. 25 shows an image intensity distribution I ₁₀ when a FLEX method is combined with a normal projection exposure apparatus,
It shows changes in I ₁₁ and I ₁₂ . The exposure conditions of the FLEX method were a total of three divided exposures, one for each of the best focus position and the position defocused by ± 1.25 μm. The simulation result of FIG. 25 and FIG.
Comparing the simulation results of 3 (C) to 3 (E), it can be seen that the effect of increasing the depth of focus in the present invention can be obtained to the same extent as in the FLEX method. FIG. 26 shows a simulation result when the polarization state control member PCM shown in FIG. 18 in the embodiment of the present invention is used. At this time, FIG. 26 (B)
As shown in, the radius K ₁ of the circular light shield FD ₁ at the center of the polarization state control member PCM is 0.31r ₂ (that is, sin θ
_K1 = 0.31NAw) is the determined relationship, the radius K ₂ of the outer intermediate annular transmitting portion FA is assumed to be set in relation 0.74r ₂ (i.e. sinθ _K2 = 0.74NAw) . Of course, as the exposure condition, NAw =
0.57, σ = 0.6 and λ = 0.365 μm remain unchanged. Even in the control member PCM as shown in FIG. 26B, the intensity distribution I ₄ at the best focus position and the intensity distribution I at the defocus position of 1 μm as shown in FIGS. 26C, 26D and 26E. ₅ , a sufficient depth-of-focus increase effect can be obtained as in the intensity distribution I ₆ at the defocus position of 2 μm.

FIG. 27 shows a conventional Super for comparison.
9 shows a result of simulation by the FLEX method. 27 (A), (B), and (C) show a pupil having a numerical aperture NAw of 0.57 and a complex amplitude transmittance of −0.3 in a portion within a radius of 0.548 NAw from the pupil center point. The intensity distribution I ₁₃ at the best focus position, the intensity distribution I ₁₄ at the defocus position of 1 μm, and the intensity distribution I ₁₅ at the defocus position of 2 μm, which are obtained when the image is provided in FIG. In the Super FLEX method, the center intensity at the best focus position is high and the profile is sharp as shown in FIG. 27, but the decrease in center intensity due to the defocus amount occurs abruptly from a certain amount. However, the effect of increasing the depth of focus is approximately the same as the effect of the present invention shown in FIGS. 23 and 26. However, Super F
In the LEX method, the area around the original image (center intensity) is shown in FIG.
Sub-peaks (ringing) as shown in (A) occur. This is not a problem for the isolated contact hole pattern PA used as the model of the simulation in FIG. 27, but becomes a serious problem when applied to a plurality of adjacent contact hole patterns described later.

In order to prevent such ringing, FIGS. 28 (A), (B) and (C) use a filter having a weaker action than the pupil filter of the Super FLEX method used as the simulation model in FIG. 27. The simulation result in the case is shown. In this case, the numerical aperture NAw of the projection optical system is 0.57, and the radius of the pupil center is 0.447 NA.
A filter with a complex amplitude transmittance of -0.3 in the portion corresponding to w is used. 28A to 28C show the intensity distribution I ₁₆ at the best focus position, the intensity distribution I ₁₇ at the defocus position of 1 μm, and the intensity distribution I ₁₈ at the defocus position of 2 μm. Although ringing is weaker than in the case of No. 27, the effect of increasing the depth of focus is also reduced at the same time.

In FIGS. 29A to 29D, two adjacent contact hole patterns PA ₁ and PA ₂ are shown in FIG.
9E shows the results of simulating image intensity distributions obtained by various exposure methods in the case of aligning with a center-to-center distance of 0.66 μm (converted on the wafer) as in 9 (E). FIG. 29
(A) shows S under the same simulation condition as FIG.
29B shows an image intensity distribution obtained by the FINCS method (the present invention), FIG. 29 (B) shows an image intensity distribution obtained by the conventional FLEX method, and FIG. 29 (C) shows Super under the same conditions as FIG. FIG. 29D shows the image intensity distribution obtained by the FLEX method (1), and FIG. 29 (D) shows the image intensity distribution obtained by the Super FLEX method (2) under the same conditions as FIG. 28. It is at the best focus position. As can be seen from this simulation result, the images obtained in FIGS. 29 (A), (C), and (D) are 2
Since the strength between two hole images is lower than the film-verification strength Ec, the resist (positive type) between both holes is completely left,
The resist images in both holes are separated and formed well. However, in the FLEX method shown in FIG. 29B, the intensity between the two hole images is not sufficiently low, the resist between the two holes is film-verified, and a good pattern cannot be formed. That is, the images of the two contact holes may be connected to each other due to a slight difference in the exposure amount. As described above, the depth of focus at the time of projecting an isolated contact hole pattern was obtained by the SFINCS method of the present invention and the conventional FLEX method to the same extent, but the resolution (fidelity) of adjacent hole patterns was In terms of points, the SFINC of the present invention
It can be seen that the S method is superior to the FLEX method.

In the simulations of FIGS. 29C and 29D, two hole patterns PA ₁ and PA ₂ are provided under the condition that the peak portion of the ringing due to one hole pattern overlaps with the central intensity portion of the other hole pattern. Since the center-to-center distance is determined, the effect of ringing does not appear between the two hole pattern images. This means that, conversely, when the distance between the centers of the _two hole patterns PA ₁ and PA ₂ is different from the previous condition (0.66 μm on the wafer), the effect of ringing appears.

FIG. 30 is a simulation result of the intensity distribution at the best focus position of two contact hole images arranged with the center-to-center distance of 0.96 μm (converted on the wafer). The image intensity distribution I _{23 obtained} by the SFINCS method (present invention) under the conditions shown in FIG. 26 is 2 as shown in FIG.
The space between two hole images is sufficiently dark, and a good resist pattern can be formed. However, S under the conditions shown in FIG.
In the upper FLEX method (1), ringing due to each of the two hole patterns is synthesized (added) as in the intensity distribution I ₂₄ of FIG. The verifying strength Ec or more) occurs, and the resist in this part is film-verified. Therefore, a good resist image cannot be obtained. On the other hand, when two hole patterns with a center-to-center distance of 0.96 μm are projected by the Super FLEX method (2) under the conditions shown in FIG. 28, the image intensity distribution I ₂₅ becomes as shown in FIG. 30 (C). . In this way, Supe is relatively weak
In the case of the r FLEX method (2), a good resist image can be obtained because the ringing is small and the film is free from the film. However, under this condition, as described with reference to FIG. 28, a sufficient depth of focus expansion effect cannot be obtained as compared with the SFINCS method of the present invention.

FIG. 31 shows another projection exposure method in which 0.7 is used for the effective radius r ₂ of the pupil on the pupil plane of the projection optical system.
FIG. 13 shows an image intensity distribution I ₂₆ of an isolated hole pattern obtained when only a circular light-shielding plate having a radius of 07 times (NAw × 0.707) is arranged. In this case also, ringing will occur around the original image,
It is difficult to apply close contact hole patterns to projection exposure.

FIG. 32 shows contact hole patterns PA ₁ , PA ₂ , PA ₃ , PA used in a memory cell portion in a DRAM as an example of a plurality of adjacent contact holes.
₄ shows an example of a two-dimensional array of ₄ . When the Super FLEX method is used for such a hole pattern group, ringing (sub-peak) occurs around each hole.
Ra, Rb, Rc, Rd occur, and the region R where they overlap
At o, the peak intensities of the four ringings will overlap. In such a case, in the case of only two hole patterns (two ringings overlap each other), the film VERY did not occur.
Even with the X method (2), the size of the sub-peak is as shown in FIG.
About twice as much as the state shown in (C), and again the film-verification strength E
Since it is c or more, good pattern transfer cannot be performed. That is, an image of a hole (ghost image) that originally does not exist on the reticle is formed at the position of the region Ro on the wafer.

On the other hand, in the case of the SFINCS method according to the present invention, as shown in FIG. 30 (A), the light intensity distribution in the middle of the two hole patterns is 1/2 or less of the film-verification intensity Ec. In the region Ro shown, even if the added intensity is further doubled from the state of FIG. Although the respective embodiments of the present invention and the operation thereof have been described above, when the illumination light ILB to the reticle R has a specific polarization direction, it is determined whether the polarization direction is appropriate or not, or the polarization state control member. A means for photoelectrically detecting a part of the light flux that has passed through the projection optical system may be provided on wafer stage WST in order to determine whether the polarization state of the imaging light flux after passing through the PCM is good or bad. When using a reticle having lines and spaces, the polarization state control member PCM may be moved out of the projection optical system PL, and a part of the illumination system may be exchanged so as to be suitable for the SHRINC method. The polarization state control member PCM may be used during projection exposure of the contact hole pattern, and a modified illumination system such as the SHRINC method or an annular illumination light source may be used together. In that case, when exchanging the reticle to be exposed from the contact hole to the line and space, only the polarization state control member PCM needs to be withdrawn.

Further, the polarization state control member PCM shown in each of the embodiments of the present invention is composed of a circular or ring-shaped transmission part, but this is not limited to a literal shape. For example, the circular transparent portion may be transformed into a polygon including a rectangle, and the annular transparent portion may be transformed into a shape surrounding the polygon in a ring shape. Furthermore, the polarization state control member PCM
In the above, the central circular transmission portion is surrounded by a maximum of two annular transmission portions, but the annular transmission portion may be divided into more parts. In that case, the areas of the circular transmission portion and the n-fold annular transmission portions are set to be substantially equal to each other, that is, the effective opening area of the pupil is divided into n + 1 equal areas.

[0076]

As described above, according to the present invention, the depth of focus during projection exposure of an isolated pattern such as a contact hole is set to F
It can be expanded to the same extent as the LEX method or the Super FLEX method, and it does not move or vibrate the photosensitive substrate in the optical axis direction unlike the FLEX method.
Further, there is an advantage that it is not necessary to prepare a spatial filter having a complex function of complex amplitude transmittance as in the Super FLEX method. In particular, in the present invention, the ringing itself, which is likely to occur due to spatial filtering on the pupil plane (Fourier transform plane) of the projection optical system, is suppressed sufficiently small, so that a plurality of contact hole patterns are arranged relatively close to each other. Even if it is
It is possible to obtain a great effect that the adverse effect (occurrence of a ghost image) caused by the superposition of the ringing sub-peak portions unlike the FLEX method is eliminated.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a conventional projection exposure method.

FIG. 2 is a diagram showing a principle configuration for carrying out the projection exposure method of the present invention.

FIG. 3 is a diagram illustrating the principle of increasing the depth of focus by the exposure method of the present invention.

FIG. 4 is a diagram showing an overall configuration of a projection exposure apparatus suitable for implementing the present invention.

FIG. 5 is a partial cross-sectional view showing a partial structure of the projection optical system.

FIG. 6 is a diagram showing a configuration of a polarization state control member PCM according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a polarization state control member PCM according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of polarization control means for uniformizing the polarization characteristics of illumination light.

FIG. 9 is a diagram showing the configuration of a polarization state control member PCM according to a third embodiment of the present invention.

FIG. 10 is a diagram showing the configuration of a polarization state control member PCM according to a fourth embodiment of the present invention.

FIG. 11 is a diagram showing the configuration of a polarization state control member PCM according to a fifth embodiment of the present invention.

FIG. 12 is a diagram showing the configuration of a polarization state control member PCM according to a sixth embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of polarization control means according to a seventh embodiment for making the polarization characteristics of illumination light different from each other and simultaneously making them incoherent in time.

FIG. 14 is a diagram showing the configuration of a polarization state control member PCM according to a seventh embodiment of the present invention.

FIG. 15 is a diagram showing the configuration of a polarization state control member PCM according to an eighth embodiment of the present invention.

FIG. 16 is a diagram showing the configuration of a polarization state control member PCM according to a ninth embodiment of the present invention.

FIG. 17 is a diagram showing a modification of the configuration of FIG.

FIG. 18 is a diagram showing the configuration of a polarization state control member PCM according to a tenth embodiment of the present invention.

FIG. 19 is a diagram showing a modification of the configuration of FIG.

FIG. 20 shows a configuration according to an eleventh embodiment of the present invention,
The structure of the projection optical system when an alignment system is used is shown.

FIG. 21 shows a structure of a mirror projection aligner according to a twelfth embodiment of the present invention.

22 shows a state in which the polarization state control member PCM according to each example of the present invention is applied to the aligner of FIG.

FIG. 23: SF of the present invention for a single hole pattern
The graph which simulated the effect by the INCS method as image intensity distribution is shown.

FIG. 24 shows a graph obtained by simulating the effect of a conventional normal exposure method on a single hole pattern as an image intensity distribution.

FIG. 25: Conventional FLE for a single hole pattern
The graph which simulated the effect by X method as image intensity distribution is shown.

FIG. 26: SF of the present invention for a single hole pattern
The graph which simulated the effect by the INCS method as image intensity distribution is shown.

FIG. 27: Conventional Sup for a single hole pattern
The graph which simulated the effect by er FLEX method (1) as image intensity distribution is shown.

FIG. 28: Conventional Sup for a single hole pattern
The graph which simulated the effect by er FLEX method (2) as image intensity distribution is shown.

FIG. 29 shows a graph in which the effect of various exposure methods on two close hole patterns is simulated as an image intensity distribution.

FIG. 30 shows the distance between two hole patterns that are close to each other.
9 is a graph obtained by simulating the effect of various exposure methods as an image intensity distribution when considering the case of 9.

FIG. 31 shows a case where only a circular light shield is provided at the center of the pupil,
6 is a graph showing that ringing occurs in the image intensity distribution of a single hole pattern.

FIG. 32 shows a relationship between a two-dimensionally distributed contact hole pattern and a ringing occurrence position.

[Explanation of symbols]

R ... Reticle W ... Wafer PL ... Projection optical system AX ... Optical axis PA, PA ₁ , PA ₂ ... Hole pattern PCM ... Polarization state control member FA ... Circular transmission Part FB: annular transmissive part ILB: illumination light

Claims (14)

[Claims] 1. An illuminating means for irradiating a mask on which a fine pattern is formed with an illuminating light for exposure, and an image of the pattern is projected onto a sensitive substrate by injecting light generated from the pattern of the mask. In a projection exposure apparatus including a projection optical system for performing a Fourier transform plane in an image forming optical path between the mask and the sensitive substrate, or a plane near the Fourier transform plane, or a plane near the Fourier transform plane. The above-mentioned projection optical system is provided with a polarization state control means for making the polarization states of the imaging light distributed in a circular region centered on the optical axis and the imaging light distributed in a region outside thereof different from each other. A projection exposure apparatus characterized by the above. 2. An illuminating means for irradiating a mask on which a fine pattern is formed with an illuminating light for exposure, and an image of the pattern projected onto a sensitive substrate by making light generated from the pattern of the mask incident. In a projection exposure apparatus including a projection optical system for performing a Fourier transform plane in an image forming optical path between the mask and the sensitive substrate, or a plane near the Fourier transform plane, a plane on the Fourier transform plane, or a plane near the Fourier transform plane. Polarized light that makes the polarization states different between the imaging light distributed in the annular zone centered on the optical axis of the projection optical system and the imaging light distributed inside or outside the annular zone. A projection exposure apparatus comprising a state control means. 3. A second polarization control means provided in the illuminating means or in an image forming optical path from the mask to the polarization state controlling means for aligning the polarization of the image forming light to a specific state. The projection exposure apparatus according to claim 1 or 2, wherein: 4. An illumination means for irradiating a mask on which a fine pattern is formed with an illumination light for exposure, and an image of the pattern is projected on a sensitive substrate by injecting light generated from the pattern of the mask. In a projection exposure apparatus including a projection optical system for performing a Fourier transform plane in an image forming optical path between the mask and the sensitive substrate, or a plane near the Fourier transform plane, or a plane near the Fourier transform plane. First polarization state control means for differentiating polarization states between light distributed in a circular region centered on the optical axis of the projection optical system and light distributed in an outer region thereof; A second polarized light which is provided in the means and generates a first illumination light having a uniform polarization characteristic and a second illumination light which has a polarization characteristic different from that of the first illumination light and is temporally incoherent. And a control means. Projection exposure device. 5. Illuminating means for irradiating a mask on which a fine pattern is formed with illumination light for exposure, and light projected from the pattern of the mask is incident to project an image of the pattern on a sensitive substrate. In a projection exposure apparatus including a projection optical system for performing a Fourier transform plane in an image forming optical path between the mask and the sensitive substrate, or a plane near the Fourier transform plane, or a plane near the Fourier transform plane. A first polarization state is different between the illumination light distributed in the annular zone centered on the optical axis of the projection optical system and the illumination light distributed inside or outside the annular zone. Polarization state control means; first illumination light provided in the illumination means and having uniform polarization characteristics, and second illumination having different polarization characteristics from the first illumination light and temporally incoherent Second polarization control means for generating light and And a projection exposure apparatus. 6. The polarization state control means comprises a pair of polarizing plates that make the polarization directions of transmitted light orthogonal to each other in the circular area or the annular area and the other area. The projection exposure apparatus according to any one of claims 1 to 5. 7. The polarization state control means is within the circular area,
Alternatively, a pair of polarizing plates that make the circularly polarized states of transmitted light opposite to each other in the ring-shaped region and the other region
The projection exposure apparatus according to any one of claims 1 to 5, wherein the projection exposure apparatus comprises a composite member with a four-wave plate. 8. The projection exposure apparatus according to claim 1, wherein the polarization state control means comprises a quarter-wave plate or a half-wave plate. . 9. The projection exposure apparatus according to claim 1, wherein the polarization state control means is made of an optical rotatory substance. 10. A Fourier transform plane in the image forming optical path, or a circular shape centered on the optical axis of the projection optical system at or near the Fourier transform surface,
10. The projection exposure apparatus according to claim 1, further comprising a ring-shaped light shielding member. 11. A drive member for replacing at least one of the polarization state control means, the second polarization control means, and the light shielding member is provided.
Item 11. The projection exposure apparatus according to any one of items 10 to 10. 12. A moving mechanism for moving or vibrating the sensitive substrate in the optical axis direction of the projection optical system during exposure of the sensitive substrate or during a plurality of exposures. Item 12. The projection exposure apparatus according to any one of items 1 to 11. 13. A mask having a plurality of isolated fine hole patterns is uniformly irradiated with exposure illumination light having a predetermined incident angle range, and the light from the mask is projected into an optical projection system. In the method of exposing each projected image of the plurality of hole patterns onto the photosensitive substrate by projecting as an image-forming light beam onto the photosensitive substrate via, a Fourier transform plane in the projection optical system, or When the image-forming light flux distributed on the near surface is divided into a circular area centered on the optical axis of the projection optical system and a ring-shaped area surrounding the outside, each of the circular area and the ring-shaped area is divided. A polarization state conversion member that makes the polarization states of the image-forming light fluxes that are transmitted and reaches the photosensitive substrate different from each other is provided in the projection optical system, and with respect to the effective aperture area of the Fourier transform surface in the projection optical system. And exposing the projected image of the hole pattern in a state where the area of the circular region is reduced to approximately half. 14. A mask having a plurality of isolated fine hole patterns is uniformly irradiated with exposure illumination light having a predetermined incident angle range, and the light from the mask is projected into a projection optical system. In the method of exposing each projected image of the plurality of hole patterns onto the photosensitive substrate by projecting as an image-forming light beam onto the photosensitive substrate via, a Fourier transform plane in the projection optical system, or When the image-forming light flux distributed on the near surface is divided into a circular region centered on the optical axis of the projection optical system and n ring-shaped regions surrounding the outside at least doubly, the circular region In the projection optical system, a polarization state conversion member is provided in the projection optical system, the polarization state conversion member changing the polarization state between image-forming light beams that reach at least one of the n ring-shaped regions and reach the photosensitive substrate. In a state where the effective aperture area of the Fourier transform surface in the projection optical system is divided into about n + 1 equal parts by the area of each of the circular area and the n annular zones,
An exposure method comprising exposing a projected image of the hole pattern.