JP2001176766A - Illuminator and projection aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminator, etc., that forms various light intensity distributions at prescribed surface. SOLUTION: This illuminator, that illuminates a mask 14 on which a prescribed pattern is formed is provided with a light source part 1 that supplies a flux of light, a conversion part for light of flux that contains diffraction optical elements, 51, 52 and 53 diffracting the flux of light from the light source part, so as to perform wavefront splitting and a relay lens 7 overlapping the diffracted fluxes of light with each other on a prescribed surface and further converting them into a flux of light of a prescribed sectional form on the prescribed surface, an optical integrator 8 that forms a substantial surface light source based on the flux of light diffracted by the conversion part, and a condenser optical system 12, that introduces the flux of light from the optical integrator to the mask, etc. Diffraction properties of the diffraction optical elements 51, 52 and 53 are variable, so that light intensity distribution at the prescribed surface can be varied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating apparatus, and more particularly to an apparatus for illuminating a mask pattern for a semiconductor integrated circuit or a liquid crystal device, and a projection exposure apparatus suitable for the illuminating apparatus.

[0002]

2. Description of the Related Art For forming a circuit pattern of a semiconductor element or the like,
Generally, a process called a photolithography technique is required. In this step, a method of transferring a reticle (mask) pattern onto a substrate such as a semiconductor wafer is usually adopted. A photosensitive photoresist is applied on the substrate, and a circuit pattern is transferred to the photoresist according to an irradiation light image, that is, a pattern shape of a transparent portion of the reticle pattern. In the projection exposure apparatus, the image of the circuit pattern to be transferred, which is drawn on the reticle, is projected and exposed on a substrate (wafer) via a projection optical system. In such a projection exposure apparatus, an optical integrator such as a fly-eye lens is used in an illumination optical system for illuminating the reticle, and the intensity distribution of illumination light applied to the reticle is made uniform. The reason why the use of an optical integrator such as a fly-eye lens makes the intensity distribution of illumination light irradiated on the reticle uniform will be described below.

FIG. 25A is a schematic diagram of an optical system using a fly-eye lens. In FIG. 25A, the light source 1
The light beam having emitted 001 is guided to the fly-eye lens 1003 by the optical system 1002. Here, since the entrance surface of each lens constituting the fly-eye lens 1003 and the illuminated surface 1006 (the reticle surface in the projection exposure apparatus) are conjugate with each other, as a result, the luminous flux incident on the fly-eye lens is The lens is divided into element lenses of the eye lens and is superimposed on the surface to be illuminated. For this reason, even if there is a large distribution of light-dark differences such as a Gaussian distribution on the fly-eye lens entrance surface, the distribution is not so large in the element lens unit of the fly-eye lens, and furthermore, it is averaged because they overlap. Thus, an extremely uniform illuminance distribution is obtained on the illuminated surface 1006.

A system that repeats a process of dividing a wavefront and superimposing the wavefront twice is conventionally known.
Hereinafter, this system is called a double fly-eye lens system. FIG. 25B shows an example of an optical system of a conventional projection exposure apparatus using a double fly-eye lens. A light beam from a light source 1 such as an excimer laser is converted from a plurality of optical elements through a mirror 3 and a quartz prism 4 for relaxing the polarization of the light beam after the cross-sectional shape of the light beam is converted into an arbitrary shape through an expander 2. Incident on the first fly-eye lens (secondary light source means) 5 and a large number of 2
A next light source image is formed. Light beams diverging from the large number of secondary light sources are condensed by the relay lens 7, and uniformly illuminate the incident surface of the second fly-eye lens 8 in a superimposed manner as shown in FIG. As a result, on the exit surface of the second fly-eye lens 8,
A large number of tertiary light source images corresponding to the product m × n of the number m of lens elements of the first fly-eye lens and the number n of lens elements of the second fly-eye lens can be formed. The luminous flux from the tertiary light source is limited in its diameter by the stop 9, condensed by the lens groups 10 and 12, and uniformly illuminates the reticle or mask 14 on which the pattern to be projected and exposed is drawn. Here, a field stop 11 for determining an illumination range is arranged in the lens groups 10 and 12. Then, based on the uniformly illuminated illumination light, the pattern formed on the reticle or mask pattern 14 is projected onto a substrate 16 as an object to be exposed via a projection lens 15.

The characteristics of a system called a double fly's eye lens with respect to a system using only a normal one fly's eye lens are as follows. In the following, in order to facilitate the description, a system using only one normal fly-eye lens is referred to as a single fly-eye lens system.

(1) The effect of equalizing the illuminance of illumination light for illuminating the reticle increases as the number of divisions of the fly-eye lens increases, but the manufacturing cost of the fly-eye lens increases. It is roughly proportional to the number of divisions. Therefore, if a large number of wavefront divisions are to be realized by a single fly-eye lens system, the manufacturing cost of the lens becomes enormous. However, in the double fly-eye lens system, the product of the number of divisions of the first and second fly-eye lenses is effectively the total number of divisions of the optical system. There is an advantage that can be obtained. For example, the first fly-eye lens is divided into 100, and the second fly-eye lens is divided into 100.
If divided, an illumination system equivalent to 10,000 (= 100 × 100) division can be obtained at the manufacturing cost of two 100-divided lenses.

(2) In the single fly-eye lens, the light distribution on the fly-eye lens incident surface is directly incident on the fly-eye lens. Therefore, if the light distribution changes due to vibration of the light source or the like, the spatial coherency of the projection exposure apparatus changes, which is not preferable. However, in the double fly-eye lens system, the light distribution on the incident surface of the second fly-eye lens is once uniformed by the first fly-eye lens. It does not change. For this reason, there is an advantage that even if vibration or the like occurs in the light source unit, the imaging performance is hardly affected.

(3) Further, the double fly-eye lens system has an advantage that the amount of collapse of illuminance uniformity when the aperture stop is replaced, that is, the amount of change from the ideal Koehler illumination state is small.

[0009]

In recent years, the performance such as the resolving power required for these exposure apparatuses has been extremely close to the theoretically calculated limit. As is generally well known, the optimal set values of the constants of the optical system (the numerical aperture of the projection lens, the numerical aperture of the illumination system, etc.) differ depending on the reticle pattern. As a matter of course, the apparatus side is required to be able to select an optimum optical system constant according to the mask pattern.

[0010] In view of this, regarding the illumination system, it is necessary that at least the numerical aperture of the illumination system be variable. In the double fly-eye lens system as shown in FIG. 25B which is handled by the present invention, in order to make the numerical aperture variable, the diameter of the aperture stop 9 is made to be a variable aperture like a camera aperture, or the aperture is stopped. Is generally switchable. However, simply changing the aperture diameter changes the aperture diameter to a small one, so that the area for blocking the light beam becomes large, and the illuminance decreases.

A decrease in illuminance in this type of exposure apparatus means a decrease in throughput, and as a result, the cost of manufactured products is increased. Of the products, especially for memories, the margin per product is extremely small, so the manufacturing cost is a particularly important item in the semiconductor and other manufacturing industries. For this reason, "illuminance" is one of the important items among various specifications of the exposure apparatus, and it is necessary to avoid a decrease in illuminance as much as possible.

In the double fly-eye lens system, a method has been proposed in which the first fly-eye lens is switched to a lens having a different focal length together with a diaphragm as a measure against illuminance reduction. For example, when reducing the diameter of the aperture stop, the first fly-eye lens is switched to one having a longer focal length. With this configuration, since the light flux concentrates near the center of the incident surface of the second fly-eye lens, the illuminance hardly decreases even if the aperture stop diameter is small.

As described above, if only the diameter of the aperture stop changes, it is possible to suppress a decrease in illuminance only by switching the focal length of the first fly-eye lens. However, in recent years, an aperture other than a circular aperture may be used as the aperture stop. For example, a ring-shaped aperture RS as shown in FIG.
And a multi-aperture stop QS as shown in FIG.

The aperture stops RS and QS shown in FIGS. 27A and 27B will be briefly described. When the reticle pattern becomes finer and exposure is performed near the resolution limit of the device, of the luminous flux emitted from the aperture stop of the illumination system, the light that contributes to the resolution is from the periphery of the aperture stop. Only the emitted light is emitted, and the light emitted from the central part of the opening has only a function of lowering the contrast of the image. In other words, when transmitting the information of the reticle to the wafer, only the light emitted from the periphery of the aperture stop gives energy for information transmission, and the light emitted from the center of the aperture only generates noise, so to speak. It will be.
Therefore, it can be said that it is desirable not to emit light from the center of the aperture stop. From such an idea, an aperture RS as shown in FIG. 27A has been devised. Aperture Q shown in FIG.
S is a stop when the pattern to be further resolved is limited to only vertical lines and horizontal lines. In this case, since the light emitted from the upper, lower, left and right sides of the aperture stop is only noise, the upper, lower, left and right sides of the aperture stop are further shielded.

In the case of such a non-circular aperture stop, it is not possible to prevent the luminous flux from reaching only the central portion where these stops shield light by simply switching the focal length of the first fly-eye lens as in the prior art. . For example, according to the conventional first fly-eye lens 5 shown in FIG. 25B, when the annular aperture stop RS is arranged at the emission end of the second fly-eye lens 8, the second fly-eye lens 8 is entirely covered. Therefore, the loss of the light amount increases (see FIG. 28). Incidentally, Japanese Patent Application Laid-Open No. 5-206007
In Japanese Patent Application Laid-Open No. H10-157, there is a proposal to prevent such a decrease in illuminance, but the apparatus becomes large in size, and there is a problem in terms of manufacturing cost, securing installation space, and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an illumination device capable of forming various light intensity distributions on a predetermined surface, a projection exposure device suitable for the illumination device, and an exposure using the exposure device. The aim is to provide a method.

[0017]

According to a first aspect of the present invention, there is provided a lighting device for illuminating a mask on which a predetermined pattern is formed, and a light source unit for supplying a light beam. A diffractive optical element that diffracts the light beam from the light source unit so as to split the wavefront, and converts the diffracted light from the diffractive optical element onto a predetermined surface to convert the light beam into a light beam having a predetermined cross-sectional shape on the predetermined surface A light beam conversion unit including an optical element, an optical integrator that forms a substantial surface light source based on the light beam from the light beam conversion unit, and an optical system that guides the light beam from the optical integrator to the mask, The diffraction characteristic of the diffractive optical element can be changed so that the light intensity distribution on the predetermined surface can be changed.

In the above-mentioned illumination device, instead of the conventional fly-eye lens, a diffractive optical element for diffracting the light beam from the light source unit so as to split the wavefront and the diffracted light from the diffractive optical element are superimposed on a predetermined surface. A light beam conversion unit including an optical element that converts the light beam into a light beam having a predetermined cross-sectional shape on a predetermined surface,
The diffraction characteristic of the diffractive optical element can be changed so that the light intensity distribution on the predetermined surface can be changed. Therefore, by changing the diffraction characteristics of the diffractive optical element, it is possible to accurately illuminate a desired area in accordance with the change in the illumination condition, and it is possible to effectively use the amount of light and achieve high illuminance.
Further, compared to the fly-eye lens, the material is small and the size is small, so that the manufacturing cost can be reduced.
Furthermore, it is possible to illuminate various shaped regions with a simple configuration.

According to a second illuminating device of the present invention, in a illuminating device for illuminating a mask on which a predetermined pattern is formed, a light source unit for supplying light of a predetermined wavelength, and a light source unit based on the light of the predetermined wavelength is substantially used. A wavefront splitting integrator forming a surface light source, and a condenser optical system that superimposes a light beam from a substantial surface light source by the wavefront splitting integrator on the mask surface or a surface conjugate to the mask surface, Between the light source unit and the wavefront splitting type integrator, a diffractive optical element that diffracts the light beam from the light source unit so as to split the wavefront, and diffracted light from the diffractive optical element are superimposed on each other on a predetermined surface. A light beam conversion unit including an optical element for converting the light beam into a light beam having a predetermined cross-sectional shape on the predetermined surface; and the incident surface of the wavefront splitting integrator is disposed substantially near the predetermined surface. And wherein the Rukoto.

In the above-mentioned illumination device, a diffractive optical element for diffracting a light beam from the light source section so as to split the wavefront and diffracted light from the diffractive optical element are disposed between the light source section and the wavefront splitting integrator on a predetermined surface. And a light beam converting unit including an optical element that converts the light beam into a light beam having a predetermined cross-sectional shape on the predetermined surface, and the incident surface of the wavefront splitting integrator is disposed substantially near the predetermined surface. You. Therefore, a desired region of the incident surface of the wavefront splitting type integrator arranged near the predetermined surface can be accurately illuminated as required, and the illumination can be used effectively and high illuminance can be achieved. Further, compared to the fly-eye lens, the material is small and the size is small, so that the manufacturing cost can be reduced. Furthermore, it is possible to illuminate various shaped regions with a simple configuration.

According to a third aspect of the present invention, there is provided an illumination device for illuminating a mask on which a predetermined pattern is formed, comprising a light source unit for supplying a light beam, and a diffractive optical element for diffracting the light beam from the light source unit. A light beam converting unit that converts a light beam having a predetermined cross-sectional shape on a predetermined surface, an optical integrator that forms a substantial surface light source based on the light beam from the light beam converting unit, and a light beam from the optical integrator that is a mask. The diffractive optical element is disposed in a closed space formed between the pair of protective optical members.

In the above-mentioned illumination device, a diffractive optical element for converting a light beam into a predetermined sectional shape is used instead of the conventional fly-eye lens, so that a desired area can be illuminated accurately.
High illuminance illumination is possible by effectively using the light quantity. Also, less material is required compared to fly-eye lenses,
In addition, since the size is small, the manufacturing cost can be reduced. Furthermore, it is possible to illuminate various shaped regions with a simple configuration. Further, in the above-described illumination device, since the diffractive optical element is disposed in the closed space formed between the pair of protective optical members, the surrounding impurity gas or the like adheres to the surface of the diffractive optical element and reduces the transmittance. Can be prevented.

In a preferred aspect of the above-mentioned apparatus, the light beam converting section includes a first diffractive optical element having a first diffraction characteristic and a second diffractive optical element having a second diffraction characteristic, and The second diffractive optical element is selectively positioned between a position in the illumination light path and a position outside the illumination light path.

The above-mentioned illumination device has a first diffractive optical element having a first diffractive characteristic and a second diffractive optical element having a second diffractive characteristic. It is possible to easily change and illuminate two pattern areas.

In a preferred aspect of the above-described apparatus, the cassette provided with the first and second diffractive optical elements therein and the diffractive optical element provided between the cassette and a position in the illumination optical path are provided. And a transport path for transporting.

In the above-mentioned illumination device, since a cassette provided to accommodate the diffractive optical element and a transport path for transporting the diffractive optical element are provided, various types of diffractive optical elements are prepared, and if necessary, If replaced, it is possible to cope with the case where the lighting conditions are variously set.

In a preferred aspect of the above apparatus, the diffractive optical element in the light beam converting section has a light intensity distribution in which the light intensity at the center of the predetermined surface is different from the light intensity at the periphery of the predetermined surface. It is characterized by having such diffraction characteristics.

In the above-mentioned illumination device, since the diffraction characteristic of the diffractive optical element has a different light intensity distribution between the central portion of the predetermined surface and the peripheral portion of the predetermined surface, regions having various shapes such as annular zones are provided. Can be efficiently illuminated.

In a preferred aspect of the above apparatus, the shape of an incident beam on the diffractive optical element in the light beam conversion unit is similar to the shape of the aperture of an element lens of the wavefront splitting integrator.

In the above illuminating device, since the shape of the beam incident on the diffractive optical element is similar to the shape of the aperture of the element lens of the wavefront splitting integrator, a substantial surface light source can be efficiently used by the wavefront splitting integrator. The mask can be formed by filling, the uniformity of the macroscopic intensity distribution can be improved, and the mask can be illuminated in a desired state.

[0031] In a preferred aspect of the above apparatus, the device is arranged between the diffractive optical element and the integrator in the light beam converting section to prevent the zero-order light emitted from the diffractive optical element from entering the integrator. A light shielding member for the

In the above-described illumination device, the light-shielding member prevents the zero-order light emitted from the diffractive optical element from entering the integrator, so that the zero-order light becomes noise light and causes a specific illumination on a mask or the like. It is possible to prevent spots from being formed and uneven illumination.

In a preferred aspect of the above apparatus, the diffractive optical element in the light beam conversion unit is positioned at a position deviated from a focal position of the optical element in an optical axis direction.

In the illumination device, since the diffractive optical element is positioned at a position deviated from the focal position of the optical element in the direction of the optical axis, it is easy to generate interference noise due to interference of diffracted lights of the same order. Can be prevented.

In a preferred aspect of the above-mentioned device, at least one of the position and the inclination of the optical element in the light beam conversion unit is adjustable.

In the above illuminating device, since at least one of the position and the inclination of the optical element in the light beam converting section can be adjusted, illumination unevenness on the mask or wafer surface can be eliminated, and Can be adjusted with high precision.

According to a fourth illumination device of the present invention, a mask on which a predetermined pattern is formed and a photosensitive substrate are relatively scanned with respect to a projection optical system to transfer the pattern to the photosensitive substrate. In an illumination device used for a projection exposure apparatus, a light source unit that supplies a light beam, a diffractive optical element that diffracts the light beam from the light source unit, and a substantial surface light source based on the light beam diffracted by the diffractive optical element And a wavefront splitting optical integrator that forms a light source, wherein the wavefront splitting optical integrator includes a plurality of element lenses, and the diffractive optical element includes an illumination area on the plurality of element lenses of the wavefront splitting optical integrator. And the illumination area by the diffractive optical element has an edge inclined with respect to a direction corresponding to the scanning direction. And it features.

In the above-described illumination device, since the illumination area by the diffractive optical element has an edge inclined with respect to the direction corresponding to the scanning direction, the plurality of element lenses corresponding to the edge may be used in the scanning direction. The illuminance distribution in the orthogonal direction (scan orthogonal direction) changes continuously. Therefore, a uniform illuminance distribution as a whole can be obtained on the photosensitive substrate in the scanning orthogonal direction.

[0039] In a preferred aspect of the above apparatus, the illumination area by the diffractive optical element has a plurality of illumination areas positioned separately from each other.

[0040] In a preferred aspect of the above apparatus, the shape of the plurality of illumination regions by the diffractive optical element is elliptical.

According to a fifth aspect of the present invention, there is provided an illumination apparatus for illuminating a mask on which a predetermined pattern is formed, wherein a light source unit for supplying a light beam and a first optical integrator for dividing a light beam from the light source unit into a wavefront. A light flux conversion unit including: a light flux from the first optical integrator; and an optical element that superimposes the light flux from the first optical integrator on a predetermined surface, and a second light flux forming a substantial surface light source based on the light flux from the light flux conversion unit. An optical integrator, and an optical system that guides a light beam from the second optical integrator to a mask, wherein the optical element includes a plurality of lens elements;
At least one of the refractive power and the focal position of the optical element can be adjusted by moving at least one of the plurality of lens elements.

In the above-mentioned illumination device, the optical element is composed of a plurality of lens elements, and at least one of the refractive power and the focal position of the optical element can be adjusted by moving at least one of the plurality of lens elements. The size, dimensional ratio, and the like of the light beam superimposed on the surface can be appropriately adjusted as needed. Therefore, the illuminance distribution on the mask can be set to a desired state, and the loss of illumination light can be minimized.

According to the projection exposure apparatus of the present invention, there is provided a first stage for supporting the mask, any one of the above-described illumination devices for illuminating the mask, a second stage for holding a substrate to be exposed, A projection optical system for projecting and exposing the image of the mask pattern thus formed onto the substrate to be exposed.

Since the projection exposure apparatus includes the illumination device according to the present invention, the mask can be efficiently illuminated. Therefore, the exposure time can be reduced,
Throughput is improved.

In the lighting device of the present invention described above,
It is preferable that the optical element in the light beam conversion unit is a zoom optical system capable of changing a focal length. The light intensity distribution on the predetermined surface can be changed by the focal length changing operation of the zoom optical system, and the size and shape of the substantial surface light source formed by the integrator can be changed.

The wavefront splitting type integrator according to the present invention is a fly-eye lens formed by integrating a plurality of optical elements (lens elements or reflecting mirror elements) in a matrix, or etching a light-transmitting substrate by etching. It includes a micro fly-eye lens or the like in which a plurality of minute lens surfaces (reflection surfaces) are provided in a matrix by a technique.

In the present invention, when the diffractive optical element is arranged in an enclosed space, the enclosed space is filled with a gas having a reduced oxygen concentration, for example, an inert gas such as nitrogen or helium. Is preferred.

In the present invention, an auxiliary optical integrator which is provided so as to be exchangeable with the diffractive optical element in the light beam conversion unit and forms a substantial surface light source based on the light beam from the light source unit is further provided. Is preferred.

Further, in the present invention, the light intensity distribution in which the light intensity is different between the central portion and the peripheral portion of the predetermined surface is, for example, an annular shape (donut shape) surrounding the optical axis of the lighting device on the predetermined surface. A light intensity distribution (ring-shaped distribution) such that the light intensity is increased in the region of the above, and the intensity is measured in a plurality of four or more regions arranged at substantially equal angular intervals around the optical axis of the lighting device on a predetermined surface. Is increased (in the case of four locations: quadrupole distribution, in the case of eight locations, octopole distribution).

The present invention relates to a projection exposure method for transferring a mask provided with a predetermined pattern onto a substrate (work) to be exposed, and the method according to any one of claims 1 to 10 of the present invention. A step of supplying illumination light to the mask by an illuminating device, and using the projection optical system arranged between the mask and the substrate to be exposed to convert the pattern image of the illuminated mask into the substrate to be exposed. And a step of forming thereon. According to this projection exposure method, a pattern image can be formed on a substrate to be exposed with high efficiency, so that the throughput is improved.

[0051]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a diagram showing a configuration of a projection exposure apparatus according to an embodiment of the present invention. A light beam from a light source 1 such as an excimer laser is converted into a desired shape by a beam expander 2 and then, via a reflecting mirror 3, a first diffractive optical element provided on a revolver 6A. The light enters the beam 51 and is diffracted into a light beam having a specific cross-sectional shape as described later. Next, the light is condensed by the relay lens 7, and the incident surface of the fly-eye lens 8, which is a wavefront split type integrator, is superimposed and uniformly illuminated. As a result, a substantial surface light source can be formed on the exit surface of the fly-eye lens 8.

Here, the light source 1 and the beam expander 2
Is a light source unit. The synthetic lens system including the fly-eye lens 8 as an optical integrator and the relay lens 7 as an optical element is an image forming optical system, which will be described later in detail, in the vicinity of the exit surface of the diffractive optical element 51. Is designed to form an image on almost the entire exit side of the fly-eye lens 8.

The light beam emitted from the surface light source on the emission side of the fly-eye lens 8 is transmitted to an aperture stop 6 provided in a revolver 6B.
After the shape of the passing light beam is restricted by 6, the light beam is condensed by the condenser optical system 10 so as to be superimposed once. The light beam thus superimposed passes through the relay optical system 12 and uniformly illuminates the reticle or mask 14 on which the pattern is drawn in a superimposed manner. Here, a field stop 11 for determining an illumination range is disposed in an optical path between the condenser optical system 10 and the relay optical system 12. Then, based on the uniform illumination light, the projection lens 15 projects and exposes the pattern formed on the reticle or the mask 14 onto the wafer 16 which is an object to be exposed.

Here, as shown in FIG. 2A, a plurality of diffractive optical elements 51, 52, 53 are provided on the revolver 6A.
A plurality of auxiliary fly-eye lenses 54, 55, 56 are provided. Then, the optical axis A is controlled by the motor MT1 shown in FIG.
By rotating the revolver 6A about X, any one of the diffractive optical element and the auxiliary fly-eye lens can be selectively switched. Similarly, the aperture stops 61 to 66 have a configuration in which stops having various aperture shapes can be selectively switched by the revolver 6B as shown in FIG. 2B.

When the auxiliary fly-eye lenses 54 to 56 are selected by rotating the revolver 6A, a double fly-eye lens system is obtained. In this double fly-eye lens system, a large number of 3 × 3 corresponding to the product m × n of the number m of lens elements of the auxiliary fly-eye lens and the number n of lens elements of the fly-eye lens 8 are provided on the exit surface of the fly-eye lens 8. A secondary light source image can be formed. Here, the auxiliary fly-eye lens 54 corresponds to the aperture stop 65, and similarly, the lens 55 corresponds to the stop 63, and the lens 56 corresponds to the stop 64, respectively. In the prior art, the first fly-eye lens corresponding to the auxiliary fly-eye lenses 54 to 56 of the present embodiment is switched to correspond to an aperture stop having a small diameter.

On the other hand, one of the features of this embodiment is that the number of options for switching the first fly-eye lens (the auxiliary fly-eye lenses 54 to 56 in this embodiment) of the prior art is increased. First to third diffractive optical elements 5
1 to 53 can be selected.

Next, the first to third diffractive optical elements 51 to 53 will be described in detail. These gratings are phase type diffractive optical elements, and are configured by disposing a plurality of minute phase patterns and transmittance patterns. FIG.
(A) is a figure which shows the cross-sectional shape which looked at the diffractive optical element from the X direction. Of the light incident on the diffractive optical element, the light transmitted through the portion indicated by A has a phase of zero, and the light transmitted through the portion indicated by B has a phase delayed by π. Therefore, when viewed from the wave optics, these two lights cancel each other out, and FIG.
As shown in (5), the zero-order light (directly transmitted light) disappears. Therefore, the light transmitted through the diffractive optical element 51 is ± 1st order light (or ± 1st order light).
The light is diffracted as secondary light) and passes through the relay lens 7.
Then, as shown in FIG. 3 (C), on a predetermined irradiation surface P, illumination having a delta (δ) function-like intensity distribution I is obtained.
By utilizing this phenomenon and using a diffractive optical element to which various variations of phase patterns and transmittance patterns are added, it is possible to obtain a desired light intensity distribution on the irradiation surface P, that is, the incident surface of the fly-eye lens 8. it can. The diffractive optical element includes all elements that diffract light based on differences in phase, transmittance, refractive index, and the like.

FIG. 4A is a perspective view showing a state where a light beam enters the first diffractive optical element 51 as an example. FIG. 4B shows a state in which the diffracted light is viewed from the X direction, and FIG. 4C shows a state in which the diffracted light is viewed from the Y direction. here,
The optical axis is the Z axis, the vertical direction perpendicular to the Z axis is the Y axis, the horizontal direction is the X axis, and the angle on the ZY plane is θ _y ,
The angle at the ZX plane and theta _x. The incident light is diffracted in the range of diffraction angles θ _{x0 to} θ _x1 and θ _{y0 to} θ _y1 by the first diffraction characteristic, so that the cross-sectional shape of the diffracted light is substantially annular. Then, an annular light intensity distribution is formed on the incident surface of the fly-eye lens 8 via the relay lens 7.

FIG. 5 is a view for explaining an illumination area formed by the first diffractive optical element 51 on the incident surface of the fly-eye lens 8. When the first diffractive optical element 51 is used, the cross-sectional shape of the diffracted light beam has a substantially annular shape due to the first diffraction characteristic. The light beam that has passed through the relay lens 7 forms a substantially uniform light intensity distribution only on the substantially annular illumination area IA indicated by oblique lines on the incident surface of the fly-eye lens 8.
Here, an annular zone indicated by a dotted line indicates an aperture area AA by the aperture stop 66 arranged corresponding to the first diffractive optical element 51. As is clear from the figure, the first diffractive optical element 5
Only the element lens 8a of the fly-eye lens 8 corresponding to the aperture shape of the aperture stop 66 can be illuminated by the annular light flux formed by the light source 1 and the relay lens 7, so that the amount of light from the light source 1 can be used very efficiently. .

On the other hand, the conventional auxiliary fly-eye lens 54
26 are the shaded areas in FIG.
For this reason, when the shape of the aperture stop disposed on the exit side of the fly-eye lens 8 is a ring shape (shaded portions are shaded portions) as shown in FIG. 27A, the auxiliary fly-eye lenses 54 to 56 are used. If used daringly, the light amount in the shaded portion in FIG. 6 is shielded, and the light amount loss increases.

The first diffractive optical element 51 can be illuminated along the contour of only the element lens 8a that contributes to the light beam passing through the annular aperture stop 66 in order to further increase the illumination efficiency. . In this case, the range of the diffraction angles θ _x , θ _y of the diffractive optical element 51 is appropriately changed to
As shown in (A), on the incident surface of the fly-eye lens 8,
The illumination area IA has a polygonal ring shape in which the light intensity distribution at the center and the light intensity distribution at the periphery are different. Thus, only the necessary element lens 8a can be illuminated, so that the annular aperture stop 66 can be illuminated extremely efficiently.

As shown in FIG. 7B, the first diffractive optical element 51 has a diffraction characteristic for converting diffracted light into a polygonal ring shape having an outer shape of a barrel shape and an inner shape of a hexagonal shape. A diffractive optical element having the same can also be used. Also in this case, the illumination area I corresponding to the size of the element lens 8a constituting the fly-eye lens 8 used for illumination is used.
A, the illuminance efficiency can be further increased while maintaining the uniformity of the illuminance.

As shown in FIG. 7C, the diffraction characteristics of the first diffractive optical element 51 are such that both the outer and inner shapes of the illumination area IA have an elliptical band shape (thick line in the figure). May be used.
With this, it is possible to perform illumination according to the size of the element lens 8a constituting the fly-eye lens 8 used for illumination, and it is possible to increase illumination efficiency while maintaining illumination uniformity.

When the element lenses 8a constituting the fly-eye lens 8 are irregular, that is, not arranged in a regular lattice, the cross-sectional shape of the diffracted light has a circular or polygonal shape, and the internal shape has a circular or polygonal shape. By using a diffractive optical element having a diffraction characteristic such as a polygonal or circular polygonal ring shape at an appropriate diffraction angle, the size of the element lens 8a constituting the fly-eye lens 8 used for illumination can be reduced. Lighting can be tailored.

FIG. 8 is a diagram for explaining the relationship between the effective area of the diffractive optical element 51 and the element lens 8a of the fly-eye lens 8. FIG. 8A shows the diffractive optical element 51 and FIG.
(B) shows a part of the fly-eye lens 8. As is clear from the figure, an effective area 51a of the diffractive optical element 51,
XY of each element lens 8a constituting the fly-eye lens 8
The cross sections are both rectangular and are set to be substantially similar. With such a setting, the macroscopic structure of the light spot sequence LM generated on the exit surface of the fly-eye lens 8 becomes the densest, and this can be approximately regarded as a surface light source. That is, the uniformity of the macroscopic light intensity distribution at the position of the aperture stop 66 on the emission side of the fly-eye lens 8 can be improved, and further, uniform illumination of the reticle 14 and the wafer 16 can be achieved.

The effective area 51a of the diffractive optical element 51
Is almost the same as the smaller one of the XY cross-sectional shape near the exit surface of the region where the optical element is formed in the diffractive optical element 51 and the XY cross-sectional shape of the beam incident on the diffractive optical element 51. In this embodiment, the area where the optical element of the diffractive optical element 51 is formed and the shape of the incident beam on the diffractive optical element 51 are both made to match the cross-sectional shape of the element lens 8 a constituting the fly-eye lens 8. .

When changing the lighting conditions, for example, the motor M
By rotating the revolver 6B by T2, an annular diaphragm 63 (diaphragm 6) having a large diameter shown in FIG.
6 having the same shape but different size) in the optical path. If the relay lens 7 is replaced with a variable-diameter optical system when the relay lens 7 is a variable zoom optical system, the first diffractive optical element 51 is kept in the optical path and fly-eye without loss of light quantity. The lens 8 can be illuminated.

When the revolver 6B is rotated by the motor MT2 and the aperture stop 61 is selected, the revolver 6A is rotated by the motor MT1 in conjunction therewith to position the second diffractive optical element 52 in the optical path. Second diffractive optical element 52
Has the second diffraction characteristic, and the cross-sectional shape of the diffracted light beam is a shape separated in four directions. And the relay lens 7
9 on the entrance surface of the fly-eye lens 8
An illumination area IA having a fourth light intensity distribution is formed as shown in FIG. Therefore, as compared with the case where the conventional auxiliary fly-eye lens is used, a cross-shaped region passing through the center is not wastefully illuminated, and the character illuminance efficiency can be extremely increased.

More preferably, when one of the fourth shapes has a polygonal shape, particularly a pentagonal shape as shown in FIG.
Since the illumination is optimal for the size of the element lens 8a that constitutes, the illuminance efficiency can be further improved while maintaining the uniformity of the illuminance.

When the element lenses 8a constituting the fly's eye lens 8 are arranged irregularly, that is, when they are not arranged in a lattice, the outer shape of the fourth diffracted light has many shapes. By using a diffractive optical element having a square diffraction characteristic, it is possible to perform illumination optimal for the required size of the element lens 8a of the fly-eye lens 8.

When the revolver 6B is rotated by the motor MT2 and the aperture stop 62 is selected, the revolver 6A is rotated by the motor MT1 in conjunction therewith to position the third diffractive optical element 53 in the optical path. Third diffractive optical element 53
Has a third diffraction characteristic, and as shown in FIG. 10, the cross-sectional shape of the diffracted light is substantially circular (barrel-shaped). And
An illumination area IA having a substantially circular light intensity distribution is formed on the incident surface of the fly-eye lens 8 via the relay lens 7. For this reason, the illuminance efficiency can be extremely increased as compared with the case where a conventional auxiliary fly-eye lens is used.

When the element lenses 8a constituting the fly-eye lens 8 are irregularly arranged, that is, when they are not arranged in a lattice, the diffraction characteristic of the diffracted light becomes polygonal. By arranging the diffractive optical element having the above, it is possible to perform illumination optimal for the size of the necessary element lens 8a constituting the fly-eye lens 8. Thereby, the uniformity of the illuminance can be maintained, and the loss of the light amount can be significantly reduced.

In the above embodiment, the effective area of the first diffractive optical element 51 and the element lens 8 of the fly-eye lens 8
Although the cross-sectional shape of “a” has been described as being similar, the cross-sectional shapes of the effective areas of the second and third diffractive optical elements 52 and 53 and the element lens 8 a of the fly-eye lens 8 are also similar to each other. Therefore, with the change in the lighting conditions, the second
And 3 diffractive optical elements 52 and 53 are also selected.
The uniformity of the macroscopic light intensity distribution at the positions of the aperture stops 61 and 62 on the exit side of the fly-eye lens 8 can be improved, and further, uniform illumination of the reticle 14 and the wafer 16 can be achieved.

In particular, when the present embodiment is applied to a scanning type projection exposure apparatus that performs exposure while moving a reticle as a projection original and a substrate as a workpiece with respect to a projection optical system, a wavefront division type Each of the plurality of element lenses 8a constituting the fly's eye lens 8 as the optical integrator has a rectangular shape (see FIG. 8B). In this case, the direction of the edge of the illumination area formed on the fly-eye lens 8 is the direction corresponding to the scanning direction in the plurality of element lenses 8a (typically, the element lens 8a
(In the direction along the short side), the illuminance distribution on the wafer as the irradiated surface may not be a desired distribution in the scanning orthogonal direction.

Therefore, especially when performing quadrupole illumination,
The directions of the edges of the four illumination areas formed on the incident surface of the fly-eye lens 8 by the diffractive optical element 52 and the relay lens 7 are set to directions corresponding to the scanning directions of the plurality of element lenses 8 a constituting the fly-eye lens 8. That is, it is preferable to incline the element lens 8a with respect to the short side direction.

FIG. 11A shows an example in which the shape of the four illumination areas IA formed on the incident surface of the fly-eye lens 8 is elliptical. FIG. 11B is a diagram showing a relationship between the plurality of illumination areas IA and the incident surfaces of the plurality of element lenses 8 a constituting the fly-eye lens 8. In this case, the edge of the illumination area IA is a direction continuously inclined with respect to the direction corresponding to the scanning direction of the element lens 8a.

As is clear from FIG. 11B, since the edge of the elliptical illumination area IA does not intersect the plurality of element lenses 8a at the same position, the illuminance distribution on the surface to be illuminated. (Deviation from a desired distribution), particularly in the scanning orthogonal direction, can be reduced.

In this case, the aperture stop 9 on the exit side of the fly-eye lens 8 can reduce the unevenness in illuminance even if the element lens of the plurality of element lenses 8a where the edge of the illumination area intersects is not shielded from light. The effect can be obtained. As a result, even when the aperture stop 9 is not used (or when the maximum aperture is used), the effect of reducing illuminance unevenness can be obtained. Therefore, even when the positions of the plurality of illumination areas IA are continuously shifted by using the relay lens 8 as a zoom optical system, the aperture stop 9 corresponding to those illumination areas IA.
It is not necessary to continuously change the position of the opening.

Further, as shown in FIG. 11C, the shape of the four illumination areas IA may be circular. From the viewpoint of improving the imaging performance, it is better to make the shape of the plurality of illumination areas IA elliptical as shown in FIG.
It is preferable to make the light amount distribution of the tertiary light source on the emission side of the fly-eye lens 8 away from the optical axis, rather than making it circular as shown in FIG.

In the scanning exposure apparatus, a plurality of illumination areas IA
Even if the direction of the edge is the same as the scanning orthogonal direction, the illuminance unevenness along this direction need not be considered because it is integrated by scanning exposure. Therefore, the shape of the plurality of illumination areas IA formed by the diffractive optical element 52 and the relay lens 7 may be a hexagonal shape as shown in FIG. In this case, if the edge of the illumination area IA is set to intersect obliquely with respect to the direction corresponding to the scanning direction of the element lens 8a, the illuminance unevenness on the surface to be illuminated can be reduced.

If the edges of the illumination area IA are set to intersect obliquely with respect to the direction corresponding to the scanning direction of the element lens 8a, the shape of the illumination area is not limited to a hexagonal shape, but may be other polygonal shapes. May be.

For example, as shown in FIG. 11E, the shape of the illumination area IA may be rectangular.

On the other hand, even if the shape of the illumination area is hexagonal or rectangular, its edge is parallel to the direction corresponding to the scanning direction of the element lens 8a (for example, FIG. 11).
Each of the illumination areas IA shown in FIG.
(In the case of rotating by 0 °), it is not preferable because the effect of reducing the unevenness of the illuminance is reduced.

In the above example, the four illumination areas I on the incident surface of the fly-eye lens 8 are assumed on the assumption that quadrupole illumination is used.
Although A was formed, the above principles can be applied to multipole illumination such as octopole illumination. In other words, the edge direction of each illumination region forming the multipole illumination formed on the incident surface of the fly-eye lens 8 is set with respect to the direction corresponding to the scanning direction of the plurality of element lenses 8a forming the fly-eye lens 8. By inclining, the uniformity of the illuminance distribution can be improved.

As described above, when a plurality of illumination regions are formed on the incident surface of the wavefront splitting integrator by the diffractive optical element and the relay lens, the edges of the plurality of illumination regions are aligned with the scanning direction of the element lens of the wavefront splitting integrator. By setting so as to be inclined with respect to the corresponding direction, it is possible to obtain the effect of improving the imaging performance and reducing the light amount loss under the state where the illuminance unevenness on the irradiated surface is reduced. . If the long axis of the illuminated castle is set in the tangential direction (sagittal direction) with the optical axis as the center, the imaging performance can be further improved.

Here, the detailed structure of the fly-eye lens 8 in the present embodiment will be described. FIG.
FIG. 12A is a diagram of the fly-eye lens 8 viewed from the side, and FIG. 12B is a diagram of the fly-eye lens 8 viewed along the optical axis. As shown, the fly-eye lens 8
Are two cover glasses 81, 8 arranged in the optical axis direction.
2. These cover glasses 8
Circular light-shielding coatings 81a and 82a are applied as light-shielding members at the center (near the optical axis) of the outer surfaces of the light-emitting elements 1 and 82. By providing the light shielding coatings 81a and 82a, it is possible to prevent the zero-order light from the diffractive optical elements 51 to 53 from reaching the pattern surface of the reticle 14 or the surface of the wafer 16 as unnecessary noise light.

Here, the zero-order light is a straight light component generated due to a manufacturing error of the diffractive optical element. This 0
The next light is collected at the focal position of the relay lens 7.
Therefore, when this zero-order light is left, for example, FIG.
In this case, a bright singular point is formed at the center of the illumination area IA, which causes uneven illumination of the reticle 14 and the wafer 16. Therefore, as shown in FIGS. 12A and 12B, light-shielding coatings 81a and 82a are applied on the optical axis to cut off the zero-order light and prevent the occurrence of illumination unevenness.

In FIG. 12, two cover glasses 81, 8
Although the light-shielding coatings 81a and 82a are applied to each of the light-emitting elements 2, it is needless to say that at least one of the light-shielding coatings 81a and 82a may be provided with a zero-order light-shielding measure. Also,
On the incident side, a rough surface processing may be performed instead of the light-shielding coating 81a.

The shape of the light-shielding coatings 81a and 82a is, in particular, the shape of the light-shielding coating 81a on the diffractive optical element side (incident side) in units of the XY cross-sectional shape of the element lens 8a constituting the fly-eye lens 8. It is desirable to keep. The incident side of the fly-eye lens 8
Since it is conjugate with the pattern surface of the reticle 14, if the incident end of the element lens 8a is partially shielded,
This is because there is a risk of causing uneven illumination.

If it is desired to make the illumination characteristics in the plane of the aperture stops 61 to 66 rotationally symmetric, the fly-eye lens 8
It is desirable to generate a rotationally symmetric light-shielding pattern on the cover glass 82 on the emission side.

FIG. 13 is an example in which the structure of the fly-eye lens 8 of FIG. 12 is modified. FIG. 13A is a side view of the deformed fly-eye lens 108, and FIG.
(B) is a diagram of the fly-eye lens 108 viewed along the optical axis. In this case, instead of applying a light-shielding coating to the cover glasses 181 and 182, the fly-eye lens 1
The element lens is replaced with a metal dummy element 183 at the center of 08. Such a dummy element 183 can be formed by applying a light shielding coating to a glass material. Dummy element 183 from glass material
Is formed, a rough surface processing may be performed on the diffractive optical element side (incident side) instead of the light-shielding coating.

The arrangement of the dummy elements 183 in the fly-eye lens 108 is not limited to the one shown in FIG. The arrangement shown in the figure can be appropriately changed according to the incident range of the zero-order light, the illumination conditions, and the like.

FIG. 14 shows the fly-eye lens 10 of FIG.
This is an example in which the structure of FIG. 8 is further modified. In this case, a dummy element 283 is formed at the center of the fly-eye lens 208, and an insertion hole (or screw hole) 283a is provided at the axis of the dummy element 283. Furthermore, cover glass 2
An opening is provided on the emission side of 81, 282, and a projection protruding from the center of a light shielding plate 284 as a light shielding member is inserted into an insertion hole 283.
a. Thus, the light-shielding plate 284 having an arbitrary shape can be attached to the fly-eye lens 20 without being held from the periphery.
8 can be arranged in the center.

Next, a case will be described in which the first diffractive optical element 51 having an annular divergence characteristic and a circular aperture stop 65 are used in combination. In this case as well, it is assumed that the 0-order light is blocked in the fly-eye lens 8 shown in FIGS.

In the illumination of such a combination, unlike the case of the aperture stop 66 described above, since there is no inner stop of the annular zone, the inner portion of the annular illumination area generated by the diffractive optical element 51 is not included in the illumination area. You can use everything up to the border. Therefore, it is possible to perform annular illumination while minimizing the light amount loss. When the second diffractive optical element 52 having the fourth divergence characteristic and the circular aperture stop 65 are used in combination, the diffractive optical element 5
The same effect as in the case of the combination of 1 and the aperture stop 65 can be obtained.

Next, a method of arranging the diffractive optical elements 51 to 53 in the revolver 6A will be described. As shown in FIG. 15, each diffractive optical element is housed in a protective container 105. This protective container 105 is provided with the diffractive optical element 51.
And a metal holder 105a for supporting
And a cover glass 105b, which is a pair of protective optical members fixed to and supported in parallel with each other. In other words, the diffractive optical elements 51 to 53 are protected by the two cover glasses 105b in the optical axis direction against the attachment of impurities such as gas generated when oxygen existing outside the protective container 105 is excited by ultraviolet rays. The direction perpendicular to the optical axis is protected by the metal holder 105a.
In this case, impurities adhere to the cover glass 105b.
Therefore, even if the transmittance is deteriorated due to the attachment of impurities, the replacement of the inexpensive cover glass 105b alone can be performed without replacing the expensive diffractive optical elements 51 to 53.
It is possible to recover the transmittance deterioration.

Here, the arrangement of the diffractive optical elements 51 to 53 in the optical axis direction will be described in detail. In the above embodiment, the diffractive optical element is arranged at a position shifted from the focal position of the relay lens 7 in the optical axis direction. This is to reduce interference noise generated on the reticle.

FIG. 16 is a schematic diagram for explaining the occurrence of interference noise. The interference noise is mainly generated by the interference of the ± first-order lights shown in FIG. 4 on the reticle surface. When the diffractive optical element 51 is disposed at the focal length of the relay lens 7, ± 1 order light generated from a certain point on the diffractive optical element 51 is generated at a symmetrical angle, so that the ± 1st order light is generated with respect to the optical axis. The light enters the symmetrical element lenses 8a and also enters the same position in each element lens 8a. These light beams merge again at the position of the field stop 11 on the reticle conjugate plane to generate interference noise.

Even if the light from the light source 1 has a divergence angle α like an excimer laser, the interference noise is not reduced. The luminous flux indicated by the dotted line in FIG. 3 indicates a component emitted with an inclination according to the divergence angle α of the light source. In such a light beam, the incident position on the element lens 8a shifts from the case of the solid line. However, the diffractive optical element 51 is
, No wavefront tilt occurs.
In the drawing, the solid line shows the wavefront WS1 at normal incidence, and the dotted line shows the wavefront WS2 at oblique incidence. Thus, even if there is a divergence angle α, no phase difference occurs,
Even if the illumination light is incident at various angles α, each angle component generates the same interference pattern on the field stop 11.
That is, averaging of the interference pattern by the divergence angle α does not occur.

FIG. 17 is a schematic diagram for explaining prevention of occurrence of interference noise in the present embodiment. In this case, the diffractive optical element 51 is moved from the focal position of the relay lens 7 by a predetermined distance d.
It can be seen that the wavefronts of the ± primary light are relatively inclined by the divergence angle α, and a phase difference is generated according to the divergence angle α. This phenomenon is understood from the fact that the angle of the light beam incident on the fly-eye lens 8 is determined by the position at which the focal plane (dotted line) of the relay lens 7 is cut off. If this phenomenon is utilized, a different interference pattern is generated on the field stop 11 for each angle α. That is, the intensity distribution of the interference noise at each angle α is averaged with each other, and the field stop 1
The interference noise on the pattern surface or the like of the reticle 14 conjugate with 1 is reduced.

The above-mentioned phase difference increases as the distance d increases, assuming that the divergence angle α is constant. Further, the phase difference is determined by the element lens 8 in the fly-eye lens 8 of interest.
The distance a increases as the distance from the optical axis increases. Here, the lowest position (distance from the optical axis) of the element lens 8a is determined to a certain value for each illumination mode. Therefore, if the divergence angle α and the lowest position of the element lens 8a are determined within the range of the illumination condition to be used, the distance is set so that the phase difference of the ± primary light with respect to the element lens 8a at the lowest position becomes equal to or longer than the wavelength. It is desirable to adjust d.

In the above description, the case where the diffractive optical element 51 is shifted by the distance d to the light source side has been described.
The same effect can be obtained even when 1 is shifted to the fly-eye lens 8 side. In the above description, the position of the diffractive optical element 51 in the optical axis direction is defined with respect to the surface on which the diffractive optical element 51 is patterned.

(Second Embodiment) FIG. 18 shows a second embodiment of the present invention.
FIG. 1 is a diagram illustrating a configuration of a projection exposure apparatus according to an embodiment. Since the basic configuration is the same as that of the device of the first embodiment, the description of the overlapping parts will be omitted.

When the first to third diffractive optical elements 51 to 53 are positioned in the optical path, the light that has passed through the diffractive optical element and illuminated on the incident surface of the fly-eye lens 8 has a speckle pattern. May cause noise, making it difficult to illuminate with a uniform illuminance (intensity) distribution. Therefore, the diffractive optical element 5
By vibrating 1 to 53 together with the revolver 6A by the vibration mechanism VB, the speckle pattern is vibrated on the incident surface of the fly-eye lens 8. As a result, the speckle pattern is smoothed by time averaging, so that a uniform light intensity distribution can be obtained.

Further, a wedge-shaped deflection prism DP is arranged between the relay lens 7 and the fly-eye lens 8, and the center of the prism DP and the optical axis AX are made to substantially coincide with each other by the motor MT3 and rotated during exposure. Accordingly, the light intensity distribution formed on the incident surface of the fly-eye lens 8 can be rotated. As a result, the spec pattern also rotates.
Light having a uniform illuminance distribution can be obtained as in the case where the diffractive optical elements 51 to 53 are vibrated. Here, one or both of vibrating the diffractive optical element and using the deflection prism DP may be performed.

Further, when the light source 1 emits pulsed light, the specification patterns may be averaged by shifting or tilting the diffractive optical elements 51 to 53 every predetermined number of pulses.

(Third Embodiment) FIG. 19 shows a third embodiment of the present invention.
FIG. 1 is a diagram illustrating a configuration of a projection exposure apparatus according to an embodiment. In FIG. 19, the portions of the condenser optical system 10 and the relay optical system 12 are simply shown, but actually have the same configuration as the corresponding portions in FIG. Other basic configurations are the same as those of the first embodiment.

The light beam converter in the apparatus of the third embodiment is different from the first and second embodiments in that a revolver is rotated to select a diffractive optical element, but instead of a plurality of diffractive optical elements housed in a cassette. By selecting a necessary diffractive optical element and arranging it on the optical path, light having a desired intensity distribution is supplied to the incident surface side of the fly-eye lens 8. For this reason, the light beam conversion unit includes a cassette 58a that houses the diffractive optical element 151 and the cassette 58a.
A transport path 58b for receiving and transporting the transport path 51;
And a supporting member 58c for receiving and supporting the diffractive optical element 151 from

The cassette 58a stores a plurality of diffractive optical elements 151 having different diffraction characteristics. This cassette 5
8a sends out a diffractive optical element 151 corresponding to a desired illumination condition based on a signal from a CPU (not shown),
The transport path 58b transports the diffractive optical element 151 sent from the cassette 58a toward the optical path of the illumination light. The diffractive optical element 151 that has passed through the transport path 58b is
c and is fixed on the optical path of the illumination light.

The unnecessary diffractive optical element 151 held in the support member 58c is removed from the optical path before replacement. That is, before unloading a new diffractive optical element 151 to be moved on the optical path from the cassette 58a,
The original diffractive optical element 151 to be removed from the optical path, that is, the diffractive optical element 151 held in the support member 58c is stored in the cassette 58a via the transport path 58b.

Here, the cassette 58a is removable and replaceable. In this case, various cassettes in which the types of the stored diffractive optical elements 151 are different are provided in advance, and a desired cassette is automatically selected and the transport path 5 is selected.
8b.

When the cassette 58a as described above is used, variations in the intensity distribution on the fly-eye lens 8 increase. For example, even when the ring-shaped diffraction characteristic is used in the same manner, various ring illuminations can be performed by combining various maximum divergence angles and minimum divergence angles. By increasing the variation of the intensity distribution on the fly-eye lens 8 in this way, the shape of the annular aperture stop arranged on the exit side of the fly-eye lens 8 is variously adjusted, and the pupil distribution of the illumination is finely adjusted. Also, the amount of illumination light is not wasted. In the above description, the case of the ring-shaped illumination has been described, but the same effect can be obtained in the case of the circular illumination and the fourth-shaped illumination.

Support member 5 for holding diffractive optical element 151
8c is a cover glass 58 similar to the case shown in FIG.
The support chamber is airtightly partitioned by d from the surroundings. It is desirable that the support chamber be purged with an inert gas such as nitrogen or helium gas. In this case, the diffractive optical element 151 can be protected from the attachment of impurities due to gas or the like generated outside the support member 58c, and only by replacing the inexpensive cover glass 58d,
It is possible to recover the transmittance deterioration. Further, the cassette 58 is connected to the transport path 58b extending from the support member 58c.
Since a is detachable, not only is it possible to prevent clouding due to impurities, but also the maintenance of the diffractive optical element 151 becomes easy.

Further, in the projection exposure apparatus according to the third embodiment, the relay lens 7 is divided into two parts, the front group 7a and the rear group 7b.
And a vibrating mirror 7c between the two groups 7a and 7b.
Has been arranged. At least one of the front group 7a and the rear group 7b is provided with a driving mechanism 72, and the front group 7a and the rear group 7b are provided.
Can be finely moved three-dimensionally or slightly rotated around a pair of axes perpendicular to the optical axis. The vibrating mirror 7c is also provided with a drive mechanism 73 so that the vibrating mirror 7c can be finely moved three-dimensionally or slightly rotated around a pair of axes perpendicular to the optical axis. The driving mechanism for changing the angle of the vibrating mirror 7c during the exposure time to reduce interference noise is as follows.
It is not shown and is provided separately from the drive mechanism 73.

In operation, at least one of the front group 7a and the rear group 7b is shifted XY or tilted XY (the Z axis is parallel to the optical axis) by the driving mechanism 72, and is formed by the diffractive optical element 151. Positioning of the illumination area and the entrance surface of the fly-eye lens 8 is performed. On the other hand, the mirror 7c can be tilted in the XY direction by the driving mechanism 73 to perform the alignment of the illumination area.

The size of the illumination area on the entrance surface of the fly-eye lens 8 is adjusted by shifting the Z direction of at least one of the front group 7a and the rear group 7b by the driving mechanism 72.

By appropriately operating the driving mechanisms 72 and 73 as described above, the illumination unevenness and the telecentricity on the pattern surface of the reticle 17 or the exposure surface of the wafer 16 can be adjusted with high accuracy. Here, the telecentricity means a small inclination of the illumination light beam incident on the wafer 16 or the like.
It means the isotropic nature of image formation on the exposure surface of the wafer 16 and the like. Illumination unevenness and telecentricity can be adjusted by shifting or tilting an optical element included in the condenser optical system 10 provided at the subsequent stage of the fly-eye lens 8. By combining with the fine movement of the optical element to be adjusted, more accurate adjustment can be performed.

(Fourth Embodiment) FIG. 20 shows a fourth embodiment of the present invention.
FIG. 1 is a diagram illustrating a configuration of a projection exposure apparatus according to an embodiment. Since the basic configuration is the same as that of the device of the first embodiment, the description of the overlapping parts will be omitted.

The relay lens 207 in the device of the fourth embodiment is a zoom lens composed of a pair of lens groups 207a and 207b, and appropriately adjusts the size of the illumination area projected on the fly-eye lens 8 by the zoom drive mechanism 207d. You can do it. The zoom drive mechanism 207d outputs
Both lens groups 207a, 2
07b can be appropriately zoomed. At least one of the two lens groups 207a and 207b can be moved independently by the electric mechanism 207e. As described above, the illumination state of the fly-eye lens 8 can be changed by independently moving the lens group 207b, so that control such as optimizing the illumination distribution according to the illumination information on the mask 14 can be performed.

Further, the condenser optical system 210 is also a zoom lens composed of a pair of lens groups 210a and 210b. Further, between the light source 1 and the diffractive optical elements 51 to 54, an optical delay element 21 for giving a multiple phase change to the light beam from the light source 1 is arranged. Further, the diffractive optical element 51
Reference numerals 54 to 54 denote a fly-eye integrator or a micro fly-eye
Can be replaced with a lens.

In operation, the light beam from the light source 1 passes through the optical delay element 21 and the diffractive optical elements 51-54.
Incident on. These diffractive optical elements 51 to 54 can be replaced with other diffractive optical elements by the same revolver 6A as shown in FIG. 1, and can form a multi-source image having arbitrary diffraction angle characteristics. The light beam emitted from the multiple light source image is collected by the relay lens 207 and enters the fly-eye lens 8 in a desired illumination area. The fly-eye lens 8 can be replaced with another fly-eye lens having a different size or the like by a revolver 6B similar to that shown in FIG. On the exit side of the fly-eye lens 8, a substantial surface light source is formed, and the luminous flux emitted from this surface light source passes through the condenser optical system 210 and passes through the relay optical system 12.
And is reflected by the mirror 13. Relay optical system 12
The light beam that has passed through the mirror 13 illuminates the pattern formed on the reticle or mask 14 in a superimposed and uniform manner.
The pattern on the reticle or mask 14 uniformly illuminated is projected onto the wafer 1
6 is projected and exposed.

Here, the relay lens 207 can illuminate the entrance surface of the fly-eye lens 8 with a desired size by changing the focal length. At this time, if the reticle 14 is not uniformly illuminated and there is uneven illumination,
One lens group 207b constituting the relay lens 207 is independently moved in the optical axis direction. Thus, the lens 207
By independently moving b, the distortion of the relay lens 207 as a zoom lens is changed,
Since the position of the formed image is also shifted, the fly-eye lens 8
Can be blurred on the side of the light incident surface. This allows
The substantial surface light source formed on the exit surface side of the fly-eye lens 8 changes, and the state of the surface light source can be adjusted.
Furthermore, if there is a change in the surface light source, the illumination unevenness on the mask 14 also changes. Therefore, the illumination unevenness can be adjusted by moving the lens 207b, and the exposure unevenness on the wafer 16 can be reduced.

Further, each lens group 207a and 207b constituting the relay lens 207 is connected to a zoom drive mechanism 207d.
The size of the illumination area on the entrance surface of the fly-eye lens 8 is
That is, the size of the surface light source formed on the exit surface side of the fly-eye lens 8 can be adjusted. By adjusting the size of the surface light source by the zoom driving mechanism 207d, when illumination unevenness occurs on the mask 14, for example, the lens group 207b of the relay lens 207 may be moved by the electric mechanism 207e as described above. By
Illumination unevenness and exposure unevenness can be adjusted.

Note that the relay lens 2 of the fourth embodiment is described.
In 07, the zoom magnification is changed by the zoom drive mechanism 207d and the illumination state of the fly-eye lens 8 is changed by the electric mechanism 207e, but it is not necessary to change both the zoom magnification and the illumination state. For example, only the zoom magnification may be changed by the zoom drive mechanism 207d, or the illumination state of the fly-eye lens 8 may be simply changed by the electric mechanism 207e.

(Fifth Embodiment) FIG. 21 shows a fifth embodiment of the present invention.
FIG. 1 is a diagram illustrating a main part of a projection exposure apparatus according to an embodiment. Since the basic configuration is the same as that of the device of the first embodiment, the description of the overlapping parts will be omitted.

The relay lens 307 in the device according to the fifth embodiment includes a pair of lens groups 307a and 307b, and the focal length and the focus position can be appropriately adjusted by a driving mechanism 307d.

When adjusting the focus position of the relay lens 307, the drive mechanism 307d is operated to operate the two lens groups 3
One of 07a and 307b is moved in the optical axis direction.

On the other hand, when adjusting the focal length of the relay lens 307, the drive mechanism 307d is operated to adjust the distance between the two lens groups 307a and 307b. At this time, both lens groups 30 are set so that the front focal plane of the entire relay lens 307 substantially matches the exit surface of the diffractive optical element 51.
7a and 307b are moved in the optical axis direction as a whole.

FIGS. 22 and 23 show changes in the irradiation area on the incident surface side of the fly-eye lens 8 when the focal length and focus position of the relay lens 307 are adjusted by the drive mechanism 307d.

FIG. 22A shows an initial illumination area IA1 having a circular shape, and FIG. 22B shows an illumination area IA2 after adjusting the focal length and the focus position. Drive mechanism 307d
By adjusting the focal length and the focus position of the relay lens 307, it is possible to change from the relatively small illumination area IA1 to the relatively large illumination area IA2. When the focal length of the relay lens 307 is reduced, the adjusted illumination area is smaller than the initial illumination area IA1.

FIG. 23 (A) shows the initial illumination area IA3 which is annular, FIG. 23 (B) shows the illumination area IA4 after the focal length has been adjusted, and FIG. 23 (C) shows the focus position. The illumination area IA5 after adjustment is shown.

As is apparent from a comparison between FIG. 23A and FIG. 23B, by adjusting the focal length of the relay lens 307 by the drive mechanism 307d, a comparatively small illumination area IA3 is similarly enlarged. It can be seen that the area can be changed to the area IA4. That is, the entire size can be appropriately changed by making the inner diameter and the outer diameter of the annular illumination proportional.

Further, as is apparent from a comparison between FIG. 23A and FIG. 23C, by adjusting the focus position of the relay lens 307 by the driving mechanism 307d, the ring zone ratio of the illumination area IA3 was changed. An illumination area IA5 can be obtained. That is, the interval between the inner side and the outer side of the annular illumination can be appropriately changed.

In this embodiment, since the focal length and the focus position of the relay lens 307 are appropriately adjusted by the driving mechanism 307d, the fly-eye lens 8 can be variably illuminated with a certain degree of freedom. Can be effectively reduced.

In the present embodiment, the number of element lenses constituting the fly-eye lens 8, that is, the integral number is 3
00 or more. For this reason, the fly-eye lens 8
Even if the illumination condition is changed only by changing the size of the light beam incident on the fly-eye lens 8 without changing the stop arranged on the exit surface side of the It can be kept low. This will be described in detail below.

Element Lens Constituting Fly-Eye Lens 8
Is assumed to have a square cross section with one side length d.
Set. Also, the radius of the illumination area of the fly-eye lens 8 is
Let R be the integral number N of the entire fly-eye lens 8
Is N = π · R^Two・ / D^Two It is given by (1). Also, the periphery of the fly-eye lens 8 is configured.
Number of element lenses N _sIs approximately N_s= 2πR / d (2) These peripheral element lenses are partially illuminated
Therefore, there is a possibility of causing illumination unevenness. One around
Illumination unevenness caused by one element lens is up to 100%
But the illuminance gradually decreases in the surrounding area
Therefore, the resulting unevenness is reduced and the absolute impact is small.
It becomes. Therefore, when considered comprehensively, one peripheral element
The effect of illumination unevenness caused by the lens is about 1/3
Can be estimated. In addition, statistics in the surrounding area
Randomness, shadows on uneven lighting due to the flat roots of those numbers
There is a sound. Therefore, in order to reduce illumination unevenness to 1% or less.
Is (1/3) · (N_s)^1/2/N<0.01 (3) Therefore, equations (1), (2) and (3)
From (1/3) ・ (2 / π)^1/2・ (D / R)^3/2<0.01 (4) Further, from equations (1) and (4), N> π · (1/3)^4/3× (2 / π)^2/4  × (0.01)^-4/3= 249 (5). That is, the number of divisions by the fly-eye lens 8 is
If it exceeds about 300, the occurrence of illumination unevenness is suppressed. Special
Even when the lighting conditions are changed, uneven lighting
It can be seen that it can be suppressed.

In the case of a scanning type exposure apparatus, one illumination area, that is, the cross-section of the element lens constituting the fly-eye lens 8 is rectangular, but illumination unevenness is generated according to substantially the same theory as described above. Can be suppressed.

In the above description, the case where the fly-eye lens 8 is used as the second optical integrator has been described. However, a rod integrator can be used instead of the fly-eye lens 8. FIG. 24 shows a modification using a rod integrator as the second optical integrator. In this case, the diffractive optical element 51
The light fluxes from to 54 illuminate the front focal plane FF of the rod integrator 408a via the relay lens 307 in a superimposed manner with a desired illuminance distribution. Rod integrator 40
A condenser lens 408b is arranged on the incident end side of 8a, and forms a light source surface near the incident end of the rod integrator. Also, the rod integrator 408a
Of the mask 14 corresponds to a reticle blind.
And the conjugate position. Also in the illustrated device, the relay lens 307 is formed of two groups of lenses, and the focal length and the focus position are adjusted, so that the size and ratio of the illumination area on the front focal plane FF can be appropriately adjusted.

In the fifth embodiment described above, the diffractive optical element is used as the first optical integrator, but it goes without saying that a fly-eye lens can be used instead.

In the fifth embodiment described above, the relay lens 307 is formed of two groups of lenses to adjust the focal length and the focus position. However, the relay lens 307 is formed of three groups of lenses, and the flywheel is formed. Telecentricity of the illumination of the eye lens 8 and the rod integrator 408a can also be ensured.

In the first to fifth embodiments described above, as the light source 1, for example, a KrF excimer laser (wavelength: 248 nm) or an ArF excimer laser (wavelength: 19
Illumination light having a wavelength of 180 nm or more, such as 3 nm), that is, exposure light can be used. In this case, the diffractive optical element 5
1 to 53 and 151 can be formed of, for example, quartz glass.

When a wavelength of 200 nm or less is used as the exposure light, the diffractive optical elements 51 to 53 and 151 are made of fluorite, quartz glass doped with fluorine, quartz glass doped with fluorine and hydrogen, and the structure determination. Temperature 1200
Quartz glass having a K or less and an OH group concentration of 1000 ppm or more, a quartz glass having a structure determination temperature of 1200 K or less and a hydrogen molecule concentration of 1 × 10 ¹⁷ molecules / cm ³ or more, a structure determination temperature of 1200 K or less and chlorine Concentration 5
Quartz glass of 0 ppm or less, and a structure determination temperature of 12
00K or less and hydrogen molecule concentration of 1 × 10 ¹⁷ molecules
/ Cm ³ or more and a chlorine concentration of 50 ppm or less.

Here, when the structure determination temperature is 1200 K or less,
And quartz glass with OH group concentration of 1000ppm or more
No. 2,770,224 filed by the present applicant.
And the structure determination temperature is 1200K or less.
And the hydrogen molecule concentration is 1 × 10 ¹⁷molecules / cm^ThreeIs over
Quartz glass, having a structure determination temperature of 1200 K or less and salt
Quartz glass with an elemental concentration of 50 ppm or less, and structure determination
Temperature is 1200K or less and hydrogen molecule concentration is 1 × 10¹⁷
molecules / cm^ThreeAnd the chlorine concentration is 50 ppm or less.
No. 29, filed by the present applicant.
No. 36138.

In the first to fifth embodiments described above, the fly-eye lens 8 and the auxiliary fly-eye lens 54
Are formed by integrating a plurality of element lenses, but these can also be micro fly-eye lenses. The micro fly's eye lens is a lens in which a plurality of minute lens surfaces are provided in a matrix on a light transmitting substrate by a method such as etching. There is virtually no functional difference between a fly-eye lens and a micro lens array in terms of forming multiple light source images,
The micro fly-eye lens is extremely small in the size of the aperture of one element lens (micro lens surface), can greatly reduce the manufacturing cost, and can be very thin in the optical axis direction. Is more advantageous.

In the first to fourth embodiments, the fly-eye lens 8 is used as the second optical integrator, but instead, a polygonal prism such as a quadrangular prism or a hexagonal prism, or a cylindrical internal reflecting surface is used. It is also possible to adopt an embodiment using a rod-type integrator having the following.

[0147]

As is apparent from the above description, according to the first illuminating device of the present invention, the diffractive optics for diffracting the light beam from the light source section so as to split the wavefront, instead of the conventional fly-eye lens. A light beam conversion unit including an element and an optical element that superimposes diffracted light from the diffractive optical element on a predetermined surface and converts the light beam into a light beam having a predetermined cross-sectional shape on the predetermined surface. The characteristics can be changed to enable the light intensity distribution on the predetermined surface to be changed. Therefore, a desired area can be accurately illuminated in accordance with a change in the illumination condition, so that the amount of light can be effectively used and illumination with high illuminance is possible.

Further, according to the second lighting device of the present invention,
A diffractive optical element that diffracts a light beam from the light source section so as to split the wavefront between the light source section and the wavefront splitting type integrator, and diffracted light from the diffractive optical element are superimposed on each other on a predetermined plane and are predetermined on the predetermined plane And a light beam converting unit including an optical element for converting the light beam into a light beam having a cross-sectional shape described above, and the wavefront splitting integrator is substantially disposed on the predetermined surface. Therefore, a desired area of the wavefront splitting type integrator arranged on the predetermined surface can be accurately illuminated as necessary, so that light quantity can be effectively used and illumination with high illuminance is possible.

Further, according to the third lighting device of the present invention,
Since a diffractive optical element that converts a light beam into a predetermined cross-sectional shape is used, a desired area can be accurately illuminated, and illumination with high illuminance can be performed by effectively using the amount of light. Further, compared to the fly-eye lens, the material is small and the size is small, so that the manufacturing cost can be reduced. Furthermore, it is possible to illuminate various shaped regions with a simple configuration.

Further, according to the fourth lighting device of the present invention,
Since the illumination area by the diffractive optical element has an edge inclined with respect to the direction corresponding to the scanning direction, the illuminance distribution in the scanning orthogonal direction continuously changes in a plurality of element lenses corresponding to the edge. . Therefore, a uniform illuminance distribution as a whole can be obtained on the photosensitive substrate in the scanning orthogonal direction.

According to the fifth lighting device of the present invention,
The optical element is composed of a plurality of lens elements, and at least one of the refractive power and the focal position of the optical element can be adjusted by moving at least one of the plurality of lens elements. The sheath size ratio and the like can be appropriately adjusted as needed. Therefore, the illuminance distribution on the mask can be set to a desired state, and the loss of illumination light can be minimized.

[Brief description of the drawings]

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

FIG. 2A is a diagram illustrating a configuration of a revolver provided with an auxiliary fly-eye lens and a diffractive optical element. (B)
FIG. 3 is a diagram showing a configuration of a revolver provided with an aperture stop.

3A is a diagram illustrating a configuration of a diffractive optical element, FIG. 3B is a diagram illustrating a state of diffracted light, and FIG. 3C is a diagram illustrating a light intensity distribution of the diffracted light.

FIG. 4A is a perspective view of a diffractive optical element, FIG.
(C) is a diagram illustrating a diffraction angle.

FIG. 5 is a diagram showing a light intensity distribution on a predetermined surface.

FIG. 6 is a diagram illustrating a loss of light amount.

FIGS. 7A, 7B, and 7C are diagrams showing other light intensity distributions (ring zones) on a predetermined surface.

FIG. 8A shows an illumination area of a diffractive optical element,
(B) shows a part of the exit end of the fly-eye lens.

FIGS. 9A and 9B are diagrams showing another light intensity distribution (fourth shape) on a predetermined surface.

FIG. 10 is a diagram showing still another light intensity distribution (barrel type) on a predetermined surface.

FIGS. 11A to 11E are diagrams illustrating a relationship between a fly-eye lens and an illumination area.

12A and 12B are a side view and a back view illustrating the structure of a fly-eye lens.

13A and 13B are a side view and a rear view illustrating another structure of the fly-eye lens.

14A and 14B are a side view and a back view illustrating still another structure of the fly-eye lens.

FIG. 15 is a side view illustrating holding and housing of the diffractive optical element.

FIG. 16 is a side view illustrating the arrangement of the diffractive optical element.

FIG. 17 is a side view illustrating the arrangement of the diffractive optical element.

FIG. 18 is a diagram illustrating a configuration of a projection exposure apparatus according to a second embodiment of the present invention.

FIG. 19 is a diagram showing a configuration of a projection exposure apparatus according to a third embodiment of the present invention.

FIG. 20 is a diagram showing a configuration of a projection exposure apparatus according to a fourth embodiment of the present invention.

FIG. 21 is a view showing a main part of a projection exposure apparatus according to a fifth embodiment of the present invention.

FIGS. 22A and 22B are diagrams illustrating an example of changing the illumination area of the second integrator in the apparatus in FIG. 21;

23 (A), (B) and (C) are diagrams illustrating another example of changing the illumination area of the second integrator in the apparatus in FIG. 21.

FIG. 24 is a diagram illustrating a modification of the device of FIG. 21.

FIG. 25A is an optical system using a fly-eye lens,
FIG. 1B is a diagram showing an optical system of a conventional projection exposure apparatus.

FIG. 26 is a diagram showing a light intensity distribution by a conventional fly-eye lens.

FIG. 27A shows the configuration of a ring-shaped aperture stop;
(B) is a diagram showing a configuration of a fourth aperture stop.

FIG. 28 is a diagram illustrating a loss of light amount.

[Explanation of symbols]

 Reference Signs List 1 light source 2 expander 3, 13 reflecting mirror MT1, MT2 motor 6A, 6B revolver 51 to 53, 151 diffractive optical element 54 to 56 auxiliary fly-eye lens 7 relay lens 8 fly-eye eye lens 61 to 66 aperture stop 10 condenser optical system 12 Relay optical system 11 Field stop 14 Mask 15 Projection optical system 16 Substrate to be exposed

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Osamu Yatsu, Inventor Nikon 3-chome, 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Masato Shibuya 3-2-2, Marunouchi, Chiyoda-ku, Tokyo Stock F term in Nikon Corporation (reference) 5F046 BA04 CA04 CB05 CB10 CB12 CB13 CB23

Claims (15)

[Claims] 1. An illumination device for illuminating a mask on which a predetermined pattern is formed, comprising: a light source unit for supplying a light beam; a diffractive optical element for diffracting the light beam from the light source unit so as to split a wavefront; A light beam conversion unit including an optical element that superimposes diffracted light from the element on a predetermined surface and converts the light beam into a light beam having a predetermined cross-sectional shape on the predetermined surface; a substantial surface based on the light beam from the light beam conversion unit An optical integrator that forms a light source; and an optical system that guides a light beam from the optical integrator to the mask. The diffractive characteristic of the diffractive optical element is used to change a light intensity distribution on the predetermined surface. A lighting device characterized by being changeable. 2. An illumination device for illuminating a mask on which a predetermined pattern is formed, comprising: a light source unit for supplying light of a predetermined wavelength; An integrator; and a condenser optical system that guides a light beam from a substantial surface light source by the wavefront splitting type integrator to the mask surface or a surface conjugate to the mask surface in a superimposed manner, the light source unit and the wavefront splitting. Between the mold integrator, a diffractive optical element that diffracts the light beam from the light source unit so as to split the wavefront, and diffracted light from the diffractive optical element overlap each other on a predetermined surface and a predetermined A light beam converting unit including an optical element for converting the light beam into a light beam having a cross-sectional shape; and an incident surface of the wavefront splitting type integrator is disposed substantially near the predetermined surface. Lighting device. 3. An illumination device for illuminating a mask on which a predetermined pattern is formed, comprising: a light source unit for supplying a light beam; and a diffractive optical element for diffracting the light beam from the light source unit, and a predetermined cross section on a predetermined surface. A light beam conversion unit that converts the light beam into a light beam having a shape; an optical integrator that forms a substantial surface light source based on the light beam from the light beam conversion unit; and an optical system that guides the light beam from the optical integrator to the mask. An illumination device, wherein the diffractive optical element is disposed in a closed space formed between a pair of protective optical members. 4. The light beam conversion unit includes a first diffractive optical element having a first diffraction characteristic and a second diffractive optical element having a second diffraction characteristic, wherein the first and second diffractive optical elements have a first diffraction characteristic. 4. The illumination device according to claim 1, wherein the diffractive optical element is selectively positioned between a position in the illumination light path and a position outside the illumination light path. 5. A cassette provided to accommodate the first and second diffractive optical elements; and a cassette provided between the cassette and a position in the illumination optical path for transporting the diffractive optical elements. The lighting device according to claim 4, further comprising: a transport path. 6. The diffractive optical element in the light beam conversion unit has a diffraction characteristic such that the light intensity at the center of the predetermined surface and the light intensity at the periphery of the predetermined surface have different light intensity distributions. The lighting device according to claim 1, wherein the lighting device has a lighting device. 7. The light beam converting section, wherein the shape of an incident beam to the diffractive optical element is similar to the shape of an aperture of an element lens of the wavefront splitting integrator. The lighting device according to the above. 8. A light shielding member disposed between the diffractive optical element in the light beam converting section and the integrator for preventing zero-order light emitted from the diffractive optical element from entering the integrator. The lighting device according to any one of claims 1 to 7, comprising: 9. The diffractive optical element in the light beam converting unit,
4. The illumination device according to claim 1, wherein the illumination device is positioned at a position deviated from a focal position of the optical element in an optical axis direction. 10. The lighting device according to claim 1, wherein at least one of the position and the inclination of the optical element in the light beam conversion unit is adjustable. 11. An illumination device used in a projection exposure apparatus for transferring a mask on which a predetermined pattern is formed and a photosensitive substrate to the photosensitive substrate while scanning the photosensitive substrate relative to a projection optical system. A light source unit for supplying a light beam; a diffractive optical element for diffracting the light beam from the light source unit; and a wavefront splitting optical integrator for forming a substantial surface light source based on the light beam diffracted by the diffractive optical element. The wavefront splitting optical integrator includes a plurality of element lenses, the diffractive optical element forms an illumination area on the plurality of element lenses of the wavefront splitting optical integrator, and the diffractive optics The illumination device according to claim 1, wherein the illumination area by the element has an edge inclined with respect to a direction corresponding to the scanning direction. . 12. The illumination device according to claim 11, wherein the illumination area by the diffractive optical element has a plurality of illumination areas positioned separately from each other. 13. The lighting device according to claim 12, wherein the shape of the plurality of illumination regions by the diffractive optical element is an elliptical shape. 14. An illuminating device for illuminating a mask on which a predetermined pattern is formed, a light source unit for supplying a light beam; a first optical integrator for splitting a light beam from the light source unit into a wavefront; A light beam conversion unit including an optical element for superimposing light beams from the integrator on each other on a predetermined surface; a second optical integrator forming a substantial surface light source based on the light beam from the light beam conversion unit; An optical system for guiding a light beam from the optical integrator to the mask, wherein the optical element includes a plurality of lens elements, and at least one of the plurality of lens elements moves to determine a refractive power and a focal position of the optical element. A lighting device, at least one of which is adjustable. 15. A first stage for supporting the mask; an illuminating device according to claim 1 for illuminating the mask; a second stage for holding a substrate to be exposed; A projection optical system for projecting and exposing the image of the pattern of the mask onto the substrate to be exposed.