WO1999036832A1 - Illuminating device and exposure apparatus - Google Patents

Abstract

An illuminating device preferable for a projection exposure apparatus used in a lithography process for fabricating a semiconductor device or a liquid crystal display. Light from a light source is collimated into a parallel beam and directed to a fly-eye lens serving as an optical integrator. A filter (100B) sectioned into filter elements (101A, 102A, 103A) corresponding to the lens elements of the fly-eye lens is disposed on the incidence side of the fly-eye lens. The distribution of transmittance of each filter element (101A, 102A, 103A) is varied substantially continuously so that the distribution of light intensity at the Fourier transformation optical plane for each of the small surfaces constituting the surface to be irradiated is determined independently of each other.

Description

 Lighting equipment and exposure equipment Technical field

 The present invention relates to a lighting device provided with an optical integrator, a method for transferring a mask pattern onto a substrate when manufacturing a device such as a semiconductor integrated circuit, a liquid crystal display element, or a thin film magnetic head provided with the lighting device. The present invention relates to an exposure apparatus used and a method for manufacturing a device using the exposure apparatus. Background art

 In a photolithography process for manufacturing semiconductor integrated circuits, etc., a pattern image of a reticle as a mask is transferred via a projection optical system onto a wafer (or a glass plate, etc.) coated with a photoresist. For this purpose, a step-and-repeat type (ie, a batch exposure type or a stepper type) projection exposure apparatus has conventionally been used. Recently, in order to expose a large area pattern without increasing the size of the projection optical system, a scanning exposure type projection exposure apparatus such as a step-and-scan method has been attracting attention.

 In this type of projection exposure apparatus, a fly-eye lens is used to correct the non-uniformity of the illuminance distribution of the exposure light on the pattern surface of the reticle as the irradiated surface and obtain a uniform illuminance distribution. An illumination device having an optical lens consisting of an optical lens or a rod lens is provided.

By the way, in recent years, in a projection exposure apparatus, as the required resolution is improved, mainly in the meridional direction even at the image height or even at the same image height. There is a problem that the line width of the projected image, which should be the same size, may be different due to the difference between the image and the sagittal direction. The fact that the line width of the projected image and, consequently, the line width of the formed pattern differs depending on the position or direction means that, for a logic circuit, for example, the amount of information processed per hour decreases, and the value of the device is reduced. It becomes a factor to lower.

 In order to reduce the change in the line width of the projected image, it is necessary to improve the imaging characteristics of the projection optical system itself. However, it is desired that the illumination device side take some measures.

 In view of the above, the present invention provides a method for projecting an image of an illuminated object by a predetermined imaging system, at different positions on an image plane, or for patterns arranged in different directions. It is a first object of the present invention to provide an illumination device capable of obtaining a projection image having a target line width, and an exposure device using the illumination device.

 Further, the present invention provides a method for directly transferring a pattern of an illuminated object without passing through an imaging system, even at a different position on the transferred image or for a pattern arranged in a different direction. A second object is to provide an illumination device capable of obtaining a transfer image having a target line width, and an exposure device using the illumination device.

 Further, the present invention provides a method for manufacturing a device capable of manufacturing a high-performance device using such an exposure apparatus, an exposure method using such an illumination apparatus, and a method for manufacturing such an exposure apparatus. The third purpose. Disclosure of the invention

A first illuminating device according to the present invention comprises a light source system (1, 2, 5, 6) for supplying illumination light, and an optical and integrator for forming a plurality of light source images from the illumination light from the light source system. 7) and the luminous flux from these multiple light source images A condenser optical system (9, 11, 12) for condensing and illuminating the irradiated surface in a superimposed manner, and a position optically conjugate to the irradiated surface or in the vicinity thereof A filter (100B; 110) is placed in the area, and the field is divided into a plurality of areas corresponding to the plurality of light source images, respectively. A filter element having a transmittance distribution is provided, and a plurality of filter elements (101A, 102A; 111, 112) provided in the plurality of regions are: In order to set the light intensity distribution on the optical Fourier transform surface for each minute surface constituting the irradiated surface independently to a predetermined light intensity distribution, the transmittance distributions that change substantially continuously each time. It has.

 According to the present invention, the light intensity distribution on the optical Fourier transform surface with respect to each minute surface constituting the irradiated surface can be set to a predetermined light intensity distribution independently of each other, so that the image height or The imaging characteristics can be made constant irrespective of the direction of the pattern on the irradiated surface. Thus, when an image of the illuminated object is projected by a predetermined imaging system, the target line width is obtained at different positions on the image plane or for patterns arranged in different directions. Can be obtained.

 Although the filter elements are provided corresponding to each light source image, each filter element is divided into a plurality of regions in order to facilitate calculation in an algorithm for optimizing the transmittance distribution. Considering this, it is convenient to provide a predetermined optimized transmittance to each of the divided areas.

However, in the filter element designed in this way, the intensity distribution of the illuminating light observed on the irradiated surface and the corresponding light intensity distribution on the Fourier transform surface are obtained at the boundaries of the plurality of divided areas. (Hence the so-called coherence factor) changes discontinuously. Therefore, in the process of optimizing the transmittance distribution, the transmittance distribution is set continuously to conclude. Image characteristics are improved.

 Next, a second illumination device according to the present invention comprises a light source system (1, 2, 5, 6) for supplying illumination light, and an optical 'integral light source for forming a plurality of light source images from the illumination light from the light source system. (7) and a condenser optical system (9, 11, 1, 12) for condensing light beams from the plurality of light source images and illuminating the irradiated surface in a superimposed manner, and has a predetermined scanning direction ( A illuminating device for illuminating the illuminated object (13) moving in the (Y direction), wherein a filter is arranged at or near an optically conjugate position with respect to the illuminated surface. The plurality of light source images are divided into a plurality of regions corresponding to the respective light source images, and the plurality of regions are provided with a filter element having a transmittance distribution independent of each other, and provided in the plurality of regions. At least a part (1 2 1) of the plurality of filter elements is A plurality of partial regions having respectively for setting the predetermined light intensity distribution independently, different transmittances from each other the light intensity distribution by an optical full one Fourier transform plane for each fine surface constituting

 (51, 52A, 52B, 53A, 53B), and the boundaries of the plurality of partial regions are inclined with respect to the predetermined scanning direction.

The present invention is applied to an apparatus in which an illuminated body such as a mask moves in a predetermined scanning direction, such as a scanning exposure type projection exposure apparatus. In this case, even if the transmittance distribution of a plurality of filter elements is not made continuous, the integration result is reflected in the scanning direction, so that the integrated light quantity is a continuous transmittance distribution. The light quantity equivalent to that set in is obtained. However, in order to obtain a substantially continuous equivalence ratio distribution after scanning, it is necessary to incline the boundary line of the partial area of the filter element (121) with respect to the scanning direction. This makes it possible to continuously and smoothly change the illumination intensity distribution on the surface to be irradiated and, consequently, the coherence factor. It is possible to obtain a projected image of a target line width at different positions on the surface or for patterns arranged in different directions.

 In these cases, if the optical integrator (7) has multiple lens elements, the filter (100B; 110) is located on the entrance side of the optical integrator It is desirable.

 In addition, a second optical system and a second condenser optical system are arranged between the light source system and the optical system (the first optical system). Is desirable. Thereby, the uniformity of the illuminance distribution on the irradiated surface is improved. In this case, a plurality of light source images are formed for each element or each light source image in the first optical 'integrator'.

In addition, it is desirable that an illuminance distribution correction filter (200) for uniforming the illuminance distribution on the surface to be irradiated be disposed near the filter. Is a light source system (1, 2, 5, 6; 300, 310, 320) that supplies illumination light, and an optical system that forms a plurality of light source images from the illumination light from this light source system. An illumination device comprising an integrator (7A) and a condenser optical system (9, 11, 12, 12) for condensing light beams from the plurality of light source images and illuminating the irradiated surface in a superimposed manner. Then, a filter (10 OA) is arranged at or near a position optically conjugate with respect to the illuminated surface, and the filter is provided in a plurality of regions corresponding to each of the plurality of light source images. Each of these areas is provided with a filter element having a transmittance distribution independent of each other. Each of the transmittance distributions of the plurality of filter elements (131, 1332, 1333,...) Provided in the plurality of regions is an optical distribution with respect to each minute surface constituting the irradiated surface. The light intensity distributions on the various Fourier transform planes are set independently to the specified light intensity distribution. And an optical Fourier transform surface (P 3) for the irradiated surface, or an aperture stop (8) having a non-axisymmetric aperture (8a; 8b) on a surface near this surface It is.

 When the illumination device according to the present invention is applied to a projection exposure apparatus for manufacturing a semiconductor device, a mask pattern as an object to be irradiated is usually mainly a pattern extending in one direction (this is called a “lateral pattern”). ) And a pattern extending in a direction perpendicular to this (this is called a “vertical pattern”). Therefore, regarding the difference between the average line widths of the projected images of the horizontal pattern and the vertical pattern, the size of the aperture of the aperture stop (8) is set to be non-axisymmetric so that it differs in the vertical and horizontal directions. The remaining components are corrected by the filter (10 OA).

 In other words, the filter (10 OA) allows the light intensity distribution on the optical Fourier transform surface for each minute surface constituting the irradiated surface to be independently set to a predetermined light intensity distribution, so that the image height The imaging characteristics can be made constant irrespective of the direction of the pattern on the irradiated surface. Thus, when projecting the image of the illuminated object with a predetermined imaging system, the target line width is obtained at different positions on the image plane or for patterns arranged in different directions. Can be obtained.

 The fourth illumination device according to the present invention may be configured such that the third illumination device illuminates an object to be illuminated (13) moving in a predetermined scanning direction; Is an elliptical shape (8a; 8b) in which the direction corresponding to the scanning direction with the optical axis as the center is the major axis direction or the minor axis direction. At this time, the fourth illumination device means that it is applied to a scanning exposure type projection exposure device such as a step-and-scan method, for example.

In this case, the mask pattern as the illuminated object is usually mainly in the scanning direction. And a vertical pattern extending in the non-scanning direction and a vertical pattern extending in the scanning direction. Therefore, by making the aperture shape of the aperture stop (8) into an elliptical shape with the long axis or the short axis in the direction corresponding to the scanning direction, the average line width of the projected image of the horizontal pattern and the vertical pattern The difference of can be corrected.

 In these cases, if the optical integrator (7 A) has multiple lens elements, the filter (10 OA) is located on the entrance side of the optical integrator and has an aperture stop. (8) is desirably located on the exit side of the Optical Integral.

 Also, between the light source system and the optical integrator (the first optical integrator), a second optical integrator (330) and a second condenser optical system (340) , 350) are preferably arranged. This improves the uniformity of the illuminance distribution on the irradiated surface. In this case, a plurality of light source images are formed for each element or light source image in the first optical 'integrator (7A).

 Further, an illumination distribution correction filter (200) for uniforming the illumination distribution on the irradiated surface may be arranged near the filter. This improves the uniformity of the illuminance distribution.

Next, a first exposure apparatus according to the present invention includes a first or third illuminating apparatus according to the present invention and a mask stage (RST) on which a mask (13) as an illuminated object is placed. A projection optical system (14), and a substrate stage (WST) for positioning a substrate (18) on which the pattern of the mask is transferred, and illuminating the mask with illumination light from the illumination device. The image of the mask pattern is transferred onto the substrate via the projection optical system. With such a projection exposure apparatus, a projected image having a target line width can be transferred regardless of the image height or the direction of the pattern.

 A second exposure apparatus according to the present invention includes a second or fourth illumination apparatus according to the present invention, a mask stage that moves a mask (13) as an illuminated object in a predetermined scanning direction, A projection optical system, and a substrate stage for moving a substrate (18) on which the pattern of the mask is transferred in a direction corresponding to the scanning direction in synchronization with the mask stage, and illuminating light from the illumination device. Then, the mask is illuminated, and the mask and the substrate are moved synchronously with respect to the projection optical system via the mask stage and the substrate stage, so that the pattern image of the mask is placed on the substrate. It is to be transferred sequentially. Such a second projection exposure apparatus is obtained by applying the second or fourth illumination apparatus of the present invention to a scanning exposure type projection exposure apparatus such as a step-and-scan method. Alternatively, a projected image of a target line width can be transferred regardless of the direction of the pattern.

 Next, a device manufacturing method according to the present invention is a device manufacturing method for manufacturing a predetermined device by using the first or second exposure apparatus of the present invention, wherein an original plate of the predetermined device is used. Patterned mask

(13) This mask is illuminated by the illuminating device using the mask, and an image of a pattern of the mask is transferred onto the substrate (18) on which the predetermined device is to be formed via the projection optical system. It is. As a result, a pattern having a target line width is formed on the substrate, and a high-performance device can be formed. Next, the third exposure apparatus of the present invention has an illumination optical system for irradiating the mask (13) with illumination light, and passes the photosensitive substrate (18) with the illumination light through the mask. In an exposure apparatus that performs exposure, an optical filter (100) that sets transmittance distributions in a plurality of regions on a surface substantially conjugate to the pattern surface of the mask in the illumination optical system independently of each other. B; 1 10) and the An optical system that makes a plurality of regions on a predetermined surface orthogonal to the optical axis in the illumination optical system substantially have an image-forming relationship with the illumination region on the mask, and the optical filter has a plurality of optical filters. In each of the regions, a transmittance distribution that changes substantially continuously is given. Such an exposure apparatus is one in which the first illumination device of the present invention uses a projection optical system or is applied to an exposure apparatus that does not use a projection optical system, so that it does not depend on the position or direction. Thus, the target line width pattern can be obtained.

 Further, the fourth exposure apparatus of the present invention has an illumination optical system for irradiating the mask (13) moving in a predetermined scanning direction with illumination light, and the photosensitive light is sensitized by the illumination light via the mask. In an exposure apparatus for exposing a substrate (18), a plurality of transmittance distributions in a plurality of regions on a surface substantially conjugate to a pattern surface of the mask in the illumination optical system are set independently of each other. An optical filter having a filter element of the type described above, and an optical system that forms a plurality of regions on a predetermined surface orthogonal to the optical axis in the illumination optical system substantially in an imaging relationship with the illumination region on the mask. At least some of the filter elements (122) of the optical filter are divided into a plurality of partial areas each having a different transmittance from each other. The boundary of the It is inclined with respect to. In such an exposure apparatus, the second illumination apparatus of the present invention does not use a projection optical system or is applied to a scanning exposure type exposure apparatus using a projection optical system.

 In this case, it is desirable that the optical system has an optical integrator and a condenser optical system, and that the predetermined surface is set at one end face of the optical integrator or in the vicinity thereof.

The optical lens is a fly-eye lens as an example, and the predetermined surface is desirably set at or near the entrance surface of the fly-eye lens. Further, it is desirable that the optical filter be disposed at or near the predetermined surface.

 Further, it is desirable to further include an optical member that makes the intensity distribution of the illumination light non-axially symmetric on the optical Fourier transform plane with respect to the pattern of the mask in the illumination optical system.

 Preferably, the optical member includes an aperture stop having a non-axisymmetric aperture disposed at or near the Fourier transform plane. This is an application of the third lighting device of the present invention.

 Next, a first exposure method according to the present invention uses the first illumination device of the present invention to superimpose a mask via an optical integret that forms a plurality of light source images from illumination light from a light source system. This is an exposure method for illuminating the mask and transferring the pattern of the mask onto a substrate, wherein a filter is arranged at or near a position optically conjugate to the surface to be irradiated. The plurality of light source images are divided into a plurality of regions corresponding to the respective light source images, and the plurality of regions are provided with filter elements each having a transmittance distribution independent of each other, and the plurality of regions provided in the plurality of regions are provided. In order to set the light intensity distribution on the optical Fourier transform surface for each minute surface constituting the illuminated surface to a predetermined light intensity distribution independently of each other, the filter elements are substantially continuous. Typically It has a changing transmittance distribution.

Further, the second exposure method according to the present invention uses the second illumination device according to the present invention, and in a predetermined scanning direction via an optical array that forms a plurality of light source images from illumination light from a light source system. An exposure method in which a moving mask is illuminated in a superimposed manner and a pattern of the mask is transferred onto a substrate, and a filter is formed at or near a position optically conjugate to the pattern surface of the mask. This filter is divided into a plurality of areas corresponding to each of the plurality of light source images. A filter element having a rate distribution is provided, and at least a part of the plurality of filter elements provided in the plurality of regions is formed on an optical Fourier transform surface with respect to each minute surface constituting the irradiated surface. In order to independently set the light intensity distribution at each of the above to a predetermined light intensity distribution, the light intensity distribution is divided into a plurality of partial areas each having a different transmittance from each other. It is inclined with respect to the predetermined scanning direction.

 A first method for manufacturing an exposure apparatus according to the present invention is a method for manufacturing a third exposure apparatus according to the present invention, which transfers a pattern of a mask onto a substrate, wherein the illumination optical system irradiates the mask with illumination light. And a stage system for positioning the mask and the substrate, and transmittance distributions in a plurality of regions on a plane substantially conjugate to the pattern surface of the mask in the illumination optical system, respectively. An optical filter to be set, and an optical system in which a plurality of areas on a predetermined surface orthogonal to the optical axis in the illumination optical system are substantially in imaging relation with the illumination area on the mask, respectively. When assembling in a positional relationship, the optical filter is provided with a transmittance distribution that varies substantially continuously in each of the plurality of regions.

Further, a second method for manufacturing an exposure apparatus according to the present invention is the fourth method for manufacturing an exposure apparatus according to the present invention, wherein a mask and a substrate are synchronously moved to transfer a pattern of the mask onto the substrate. An illumination optical system that irradiates the mask moving in a predetermined scanning direction with illumination light, a stage system that positions the mask and the substrate, and a pattern surface of the mask in the illumination optical system that is substantially equivalent to the mask surface. An optical filter having a plurality of filter elements that independently set the transmittance distribution in a plurality of areas on a plane conjugate to the optical axis, and a plurality of filters on a predetermined plane orthogonal to the optical axis in the illumination optical system. When assembling the optical systems in a predetermined positional relationship with each other in a predetermined positional relationship between the optical system and the optical system that makes each area substantially the image forming area of the illumination area on the mask, at least Also, some of the filter elements are divided into a plurality of sub-regions each having a different transmittance, and the boundaries of the plurality of sub-regions are inclined with respect to the predetermined scanning direction. It is. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram showing a projection exposure apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing the state of illumination light at different positions on the pattern surface of reticle 13 in FIG. 1, and the light amount distribution and the like for correcting the state of this illumination light. FIG. 3 is a diagram showing an example of a light intensity distribution of light beams at different positions illuminating the reticle 13 for correcting the state of FIG. FIG. 4 is a diagram showing an example of a filter 100 that can be used to obtain the light intensity distribution of FIG. FIG. 5 is a main part diagram for explaining how to measure the light intensity distribution of the light beam condensed on the image plane of the projection optical system 14. FIG. 6 is a diagram showing a transmittance distribution of the filter 100B of the first example of the first embodiment of the present invention. FIG. 7 is a diagram showing a transmittance distribution of the filter 110 of the second example of the first embodiment of the present invention. FIG. 8 is a diagram showing a transmittance distribution of a filter element according to a first modification of the second embodiment. FIG. 9 is a diagram showing a transmittance distribution of a filter element according to a second modification of the second embodiment. FIG. 10 (a) is a perspective view showing a filter 100A, a fly-eye lens 7A, and an aperture stop 8 according to the second embodiment of the present invention, and FIG. 10 (b) shows an illumination area on a reticle. FIG. Fig. 11 (a) shows an example of the transmittance distribution of each fill element of the filter 100A of Fig. 10 (a). Fig. 11 (b) shows the aperture stop 8 of Fig. 10 (a). FIG. 11 (c) is a diagram showing another example of the shape of the aperture of the aperture stop 8. FIG. FIG. 12 is a diagram illustrating an example of the resolution of the projected image of the horizontal pattern and the vertical pattern at each position in the running direction. Figure 13 shows the coherence factor (σ value) and projection FIG. 4 is a diagram illustrating an example of a relationship with image resolution. FIG. 14 is a diagram showing a main part of an embodiment in which the present invention is applied to a lighting device having a double fly-eye lens configuration. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, a first preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing the projection exposure apparatus of this embodiment. In FIG. 1, a mercury lamp is used as an example of the light source 1 for exposure, and g is used as illumination light for exposure. Line (wavelength 436 nm) or i-line (wavelength 365 nm) is used. However, in order to further increase the resolution, it is desirable to use excimer laser light such as KrF (wavelength: 248 nm) or ArF (wavelength: 193 nm) as the illumination light. Furthermore, it is also possible to use excimer laser light such as F ₂ (wavelength: 157 nm) as illumination light.

 In this example, the light source 1 is disposed at the first focal point of the converging mirror 2 formed of a spheroid. Then, the light beam emitted from the light source 1 is condensed by the converging mirror 2 and once converged on the second focal point of the converging mirror 2 via the mirror 3. On the optical path near the second focal point, a shirt 4 is arranged to be openable and closable. When the shirt 4 is in the open state, the luminous flux passing through the second focal point is almost parallel by the collimating lens 5. The light is converted into a luminous flux, and the exposure wavelength (g-ray or i-ray when the light source 1 is a mercury lamp) is selected by the bandpass filter 6. In this example, a light source system is configured by the light source 1, the condenser mirror 2, the collimating lens 5, and the bandpass filter 6.

The luminous flux that has passed through the bandpass filter 6 is converted to a fly-eye lens 7 composed of a number of lens elements as an optical * intelligent lens. The light enters, and many primary light source images (secondary light sources) are formed on the exit side surface. The luminous flux diverging from these secondary light sources is restricted by the aperture stop 8 of the illumination system after its cross-sectional shape and size are restricted, and then the condenser optical system composed of the first condenser lens 9 and the second condenser lens group 11 The reticle 13 illuminates the pattern surface of the reticle 13 on which the pattern to be projected and exposed as the illumination light IL for exposure is drawn. At this time, a mirror 12 for bending the optical path is inserted near the middle of the second condenser lens group 11, and the mirror 12 bends the optical path of the light beam downward. A field stop (reticle blind) 10 is arranged between the first condenser lens 9 and the second condenser lens group 11 so as to be conjugate with the pattern surface (lower surface) of the reticle 13. 10 determines the illumination area of the pattern surface.

 Further, the arrangement surface P 3 of the aperture stop 8 is set to an optical Fourier transform surface with respect to the pattern surface of the reticle 13 or in the vicinity thereof. When the fly's eye lens 7 is used as an optical 'integrator' (homogenizer), it is preferable that the arrangement surface P 3 is the exit surface of the fly's eye lens 7 (more precisely, the exit side focal plane). As an optical integration, it is conceivable to use a rod integrator (open lens) in addition to the fly-eye lens. In this case, the fly-eye lens 7 has its incident surface located on a conjugate surface with the pattern surface of the reticle 13 and its exit surface (the exit-side focal plane) serves as an optical Fourier transform surface for the pattern surface. Be placed. On the other hand, in the case of the rod integrator, the incident surface is arranged on the above-mentioned Fourier transform surface, and the emission surface is arranged on the above-mentioned conjugate surface.

Under the illumination light IL, an image of the pattern in the illumination area on the pattern surface of the reticle 13 is projected through the projection optical system 14 to a projection magnification of 3 (3 is, for example, 1 1/5, which is represented by the same magnification in FIG. 1), and is projected onto the shot area to be exposed on the wafer 18 coated with the photoresist. An optical Fourier transform plane (hereinafter referred to as a “pupil plane”) for the pattern surface of the reticle 13 between the front group and the rear group of the projection optical system 14. A numerical aperture is defined on P 2. An aperture stop 15 is installed. Hereinafter, the Z axis is taken parallel to the optical axis AX of the projection optical system 14, the X axis is taken parallel to the plane of FIG. 1 in a plane perpendicular to the Z axis, and the Y axis is taken perpendicular to the plane of FIG. Will be explained.

 First, the reticle 13 is placed in the XY plane such that the pattern surface is substantially arranged on the first surface (object surface) of the projection optical system 14 in the above-mentioned illumination area. The reticle stage RST is held on the reticle stage RST, which is positioned by the, and the position of the reticle stage RST is measured by a laser interferometer not shown. On the other hand, the wafer 18 is held by vacuum suction on a wafer holder (not shown) so that this surface is substantially arranged on the second surface (image surface) of the projection optical system 14. Stage Fixed on WST. The position of the wafer stage WST in the XY plane is measured by a laser interferometer (not shown), and the position (focus position) of the wafer 18 in the optical axis AX direction is measured by an autofocus sensor (not shown). The wafer stage WST aligns the surface of the wafer 18 with the image plane of the projection optical system 14 by the autofocus method, and positions the wafer 18 in the X and Y directions. Further, a light-shielding plate 19 having a pinhole formed thereon is fixed near the wafer 18 on the wafer stage WST, and the bottom of the light-shielding plate 19 is used for measuring the light intensity distribution of the aerial image as described later. The measurement system is located.

When the projection exposure apparatus of the present example is of a step-and-repeat type (stepper type), when exposure to one shot area on the wafer 18 is completed, the wafer stage WST is moved step by step to move the wafer 18 onto the wafer 18. The next shot area moves to the exposure area by the projection optical system 14, and the operation of exposing the pattern image of the reticle 13 is repeated. Further, when the projection exposure apparatus of this example is of a scanning exposure type such as a step-and-scan method, and the Y direction is the scanning direction, the reticle 13 is illuminated by a slit-shaped illumination area elongated in the X direction. You. Then, after the shot area to be exposed on the wafer 18 is moved to the scanning start position by the step movement of the wafer stage WS, the reticle stage RST and the wafer stage WST are synchronously driven, and the reticle 13 and the wafer By relative scanning of 18 with respect to the projection optical system 14 in the Y direction with the projection magnification i3 as the speed ratio, the pattern image of the reticle R is sequentially transferred onto the shot area.

 Next, in the projection exposure apparatus of the present example, the projection of the pattern arranged at a different position on the image plane (surface of the wafer 18) of the projection image by the projection optical system 14 of the reticle 13 or in a different direction. A configuration for obtaining a projection image having a target line width for each image will be described. First, the entrance surface of each lens element constituting the fly-eye lens 7 (hereinafter, referred to as “the entrance surface P l of the fly-eye lens 7”) is the surface of the reticle 13 and the surface of the wafer 18, respectively. (Wafer surface). A filter 100 is arranged near the entrance surface P1 of the flyer lens 7, and the filter 100 has a predetermined transmittance distribution.

 By giving the filter 100 a predetermined transmittance distribution, when a pattern having the same line width is formed at a different position on the pattern surface of the reticle 13, the For example, images having the same line width can be obtained at different positions, for example, at the center of the field of view on the image plane side of the projection optical system 14 and at the periphery of the field of view. This will be described with reference to FIG.

FIG. 2A shows the center of the field of view of the projection optical system 14 on the object plane side (on the optical axis AX), that is, the center of the illumination area of the reticle 13. 3 shows the state of the illumination light beam without the provision of. Figure 2

(b) shows the state of the illumination light flux without the filter 100 at the periphery of the visual field, that is, at the periphery of the illumination area of the reticle 13. Here, towards the light flux condensed in the center of the visual field opening angle than light beam condensed at the periphery of the visual field (hence, the numerical aperture NA _IL of the illumination system) is slightly smaller state, the center of the visual field of the It is assumed that both the light flux condensed at the portion and the light flux condensed at the periphery of the visual field have a uniform light intensity distribution. In this case, the value (NA _IL / NA _PL ) of the ratio of the numerical aperture NA _PL of the projection optical system 14 to the numerical aperture NA! _L of the illumination system is the coherence factor (σ value).

In such a case, in general, when the pattern to be transferred is an isolated pattern, a larger numerical aperture NA _1L (larger σ value) of the illumination system can faithfully transfer a thinner pattern. it can. In other words, a pattern that is narrower in the peripheral part of the visual field can be transferred than in the central part of the visual field, and this is shown in FIGS. 2 (c) and (d).

 With the conventional filtering technology, the same effect is obtained in the central part and the peripheral part of the visual field when the filter is used. On the other hand, in the present example, for example, although only one filter 100 is used, filtering with different effects can be performed between the central part of the visual field and the peripheral part of the visual field. In order to achieve this, in the present example, the filter 100 is arranged at a position conjugate to the pattern surface of the reticle 13 as a surface to be irradiated, or in the vicinity thereof. When the optical integration is performed by the fly-eye lens 7 as described above, it is preferable to dispose the filter 100 on the incident surface P 1 of the fly-eye lens 7.

Then, a filter 100 is arranged on the entrance surface P1 of the fly-eye lens 7 to correct the state shown in FIG. When the illumination is reduced, the intensity distribution of the illumination light on reticle 13 is shown in Fig. 3. It becomes as shown in.

 In FIG. 3, the luminous flux incident on the center of the reticle 13 in order to keep the light intensity distribution of the luminous flux condensed at the center of the pattern area of the reticle 13 (field of view on the object side) almost unchanged. The intensity distribution of ILa is almost constant irrespective of the angle of incidence. On the other hand, in order to reduce the numerical aperture NAIL of the light beam condensed on the periphery of the pattern surface of the reticle 13, the intensity distribution of the light beam ILb incident on the periphery gradually decreases as the incident angle increases. ing. Actually, as shown in Fig. 2 (e), the distribution of the light quantity I of the light flux I Lb gradually decreases with respect to the sine of the incident angle (N.A.). FIG. 4 shows the transmittance distribution of the filter 100 for correcting the state of FIG. 2. In FIG. 4, the central part of the filter 100 has a large number of identical shapes constituting a fly eye lens 7. Are divided into a number of rectangular fill elements 101, 102, etc. of the same size corresponding to the lens elements 71, 72, etc. of the respective lens elements 101, 102, etc. It is configured so that the transmittance distribution can be set independently. In this example, the transmittance distribution of the filter element 1002 existing at the center of the filter 100 and the filter element 101 existing at the periphery of the filter 100 are almost reversed. I have. This is because the illuminance distribution of all the fill elements is superimposed on the illuminated surface (the pattern surface of reticle 13), so that the illuminance on the illuminated surface is constant at any position. In the filter 100 in FIG. 4, the white part is the part with the highest transmittance, the densely shaded part is the part with the lowest transmittance, and the coarse shaded part is not as dense as the densely shaded part. The low transmittance portions are shown.

Each position in the minute rectangular area of a large number of fill elements forming the fill 100 corresponds to each position in the irradiated surface (the pattern surface of the reticle 13). For example, at the center of the field of view, the center of each fill element The light beam of the position becomes incident. Therefore, at the center position of the field of view, the same light intensity distribution is obtained at any angle of incidence. On the other hand, for example, at the upper right peripheral position in the field of view, light rays at the upper right peripheral position of each fill element are incident. At this time, the upper right peripheral portion of the first filter element 102 located at the center of the filter 100 has high transmittance, so that the light intensity at the center of the light beam remains high. On the other hand, since the transmittance is low at the upper right peripheral position of the second filter element 101 existing around the filter 100, the light intensity of the light beam having a large incident angle is low.

 In this way, as shown in FIG. 3, the light intensity distribution (and, consequently, the coherence factor) with respect to the incident angle of the incident light beam can be changed only in the peripheral portion of the irradiated surface. In other words, the light intensity distribution shown in Fig. 2 (e) can be achieved in the periphery of the irradiated surface. In the above description, the filter 100 is arranged at or near a position conjugate to the surface to be illuminated. However, this is because the light intensity distribution on the optical Fourier transform surface with respect to the surface to be illuminated is eventually determined. This is equivalent to independently changing each point on the irradiation surface.

 An example of a method of setting the transmittance distribution of the filter 100 will be described with reference to FIG.

 First, in FIG. 1, the light intensity distribution of the light beam condensed on the image plane (the surface of the wafer 18) of the projection optical system 14 without the filter 100 is measured. For this purpose, the wafer stage WST is driven, and the light-shielding plate 19 having a pinhole is moved in the X and Y directions within the exposure area of the projection optical system 14 so that the angle of incidence of the illumination light IL is adjusted at each position. The corresponding light quantity distribution is measured.

FIG. 5 is an enlarged view showing a main part when the light shielding plate 19 is moved within the exposure area of the projection optical system 14 in such a manner. In FIG. 5, the pinhole 19 a of the light shielding plate 19 is shown. A condensing optical system 20 is arranged at the bottom of the lens, and a two-dimensional image sensor such as a CCD type (not shown) is provided on a focal plane 21 on the rear side of the condensing optical system 20. The image pickup surface is arranged, and the light quantity distribution on the rear focal plane 21 is measured by this image pickup device. In this case, the position of the pinhole 19a is the front focal position of the condensing optical system 20. Instead of measuring the light amount distribution at a time with a two-dimensional image sensor, the rear focal plane 21 may be scanned with a pinhole to measure the light amount distribution.

 The ideal performance of the condensing optical system 20 is that the aberration is astigmatism except for distortion, the projection relationship is fsin θ instead of ft an 0, which is normally ideal, and the transmittance is independent of the position and direction. It was constant (almost 100%). However, since it is actually difficult to obtain an ideal optical system, the performance of the condensing optical system 20 is measured in advance to determine the deviation from the ideal state, and when the measurement is performed thereafter, What is necessary is just to correct the measurement result in consideration of the deviation from the ideal state.

 The reason for arranging the pinhole 19a so that the position of the pinhole 19a is the front focal position of the condensing optical system 20 is because of the influence of the angular characteristics of the imaging device and the like arranged on the rear focal plane 21. It is to eliminate. The measurement is performed on the focal plane 21 on the rear side of the condensing optical system 20 because this position is conjugate with the pupil plane of the projection optical system 14 (the installation surface of the aperture stop 15). As a result, the light quantity distribution on the rear focal plane 21 becomes a light quantity distribution corresponding to the numerical aperture (and, consequently, the coherence factor) of the illumination light incident on the pinhole 19a as it is. If the projection magnification 3 of the projection optical system 14 is not equal to 1, the measurement result may be converted into a light amount distribution on the incident side of the projection optical system 14.

 By measuring the light quantity distribution through the pinhole 19a at each position of the exposure area (field of view on the image plane side) of the projection optical system 14 as described above, each of the positions on the image plane of the projection optical system 14 is obtained. The light intensity distribution according to the incident angle of the light beam condensed on each point on the pattern surface (object plane) of the reticle 13 can be measured.

Next, provisional setting of the transmittance distribution of the filter 100 in FIG. 1 is performed. After Figure 5 When the position where the light intensity distribution in the light beam condensed on the focal plane 21 on the side is to be corrected is determined, the transmittance of the lens element of the corresponding fly-eye lens 7 is determined, and the light on the surface of the wafer 18 is determined. When the position where the intensity distribution is to be corrected is determined, the corresponding position on the incident surface of the lens element of the fly-eye lens 7 is determined. By reducing the transmittance of the portion where the light intensity is higher than the desired intensity to the desired intensity, an arbitrary light intensity distribution of the light beam condensed at each point on the wafer surface (image surface) can be obtained. . The filter obtained in this way is called a temporary filter.

 Next, this temporary filter is installed on the entrance surface of the fly-eye lens 7, and the illuminance distribution on the wafer surface is measured. For this purpose, an imaging surface of a two-dimensional CCD or other two-dimensional imaging device may be arranged in the exposure area of the projection optical system 14 in FIG. 1, and the light amount distribution in the exposure area may be measured at one time. In addition, a photoelectric sensor having a pinhole in the exposure area may be two-dimensionally scanned. From this measurement result, in order to obtain a desired illuminance distribution, the transmittance distribution of the filter 100 arranged at a position conjugate with the wafer surface, that is, the incident surface P1 of the fly-eye lens 7, is calculated. The desired transmittance distribution of the filter 100 is obtained by calculating the product of the transmittance distribution and the transmittance distribution of each of the areas corresponding to the lens elements of the fly-eye lens 7 of the above-mentioned temporary filter.

 Note that the above temporary filter is provided for convenience of explanation, and in practice, the calculation corresponding to the process of manufacturing the temporary filter and measuring the illuminance unevenness is performed simultaneously when the transmittance of the filter is temporarily set. Is preferred. This is because there is a risk that manufacturing errors may occur when creating a temporary file.

As another example of a method of setting the transmittance distribution of the filter 100, for example, the light intensity distribution of the light beam condensed on the illuminated surface is roughly known, and the unevenness of the line width of the projected image is corrected. If this is the only purpose, there is a method of actually printing and developing. In this way, the result On the other hand, the transmittance may be set so that a desired image can be formed by the imaging simulation.

 Although the above embodiment has been described on the assumption that the projection exposure apparatus uses a single fly-eye lens, a so-called double fly-eye lens configuration can be adopted. In the double fly-eye lens configuration, an auxiliary (second) optical integrator (such as a fly-eye lens) and an auxiliary condenser optical system are placed between the light source system in Fig. 1 and the fly-eye lens 7 as an optical integrator. Is arranged.

 FIG. 14 (a) is a plan view showing an essential part of an example of a lighting device having a double fly-eye lens configuration, and FIG. 14 (b) is a side view showing the lighting device. This illumination device is used as an illumination optical system of a step-and-scan type projection exposure apparatus. The Y direction corresponds to the scanning direction of the reticle and the scanning device, and the X direction corresponds to the scanning direction. In Figs. 14 (a) and (b), the rectangular shape output from the laser light source 300 composed of an excimer laser light source such as KrF or ArF Illumination light composed of a laser beam having a cross-sectional shape passes through a shaping cylindrical lens 310, 320, and its cross-sectional shape is enlarged, and then enters a front stage fly-eye lens 330. Then, the illumination light from the multiple light source images formed on the exit surface of the fly-eye lens 330 passes through the relay lenses 340 and 350 and enters the subsequent fly-eye lens 7A. And

Illumination light from a large number of light source images formed on the exit surface of the fly-eye lens 7A passes through the elliptical aperture of the aperture stop 8, and has an optical system similar to that of the first condenser lens 9 and thereafter in FIG. Head for.

In this case, as shown in FIG. 14 (d), the fly-eye lens 7 A at the subsequent stage has a cross section substantially corresponding to the rectangular illumination area on the reticle (not shown). It is configured by bundling similar rectangular lens elements 7a in 12 rows in the Y direction and 3 columns in the X direction. Also, the cross-sectional shape of the fly-eye lens 7A as a whole is almost square, and as shown in FIGS. 14 (a) and (b), the entrance surface of the fly-eye lens 7A corresponds to the lens element 7a. A filter 10 A composed of a large number of filter elements is disposed, and an aperture stop 8 is disposed on the exit surface of the fly-eye lens 7 A. The transmittance distribution of each filter element of the filter 100 A, and the shape of the axially symmetric or non-axially symmetric aperture of the aperture stop 8 can be set in the same manner as described below.

 As shown in FIG. 14 (c), the fly-eye lens 330 in the former stage has a square lens element 330a whose cross-sectional shape is almost similar to the entire cross-sectional shape of the fly-eye lens 7A. It consists of three rows in the Y direction and 12 columns in the X direction. The entrance surface of the fly-eye lens 330 is set to be conjugate with the entrance surface of the fly-eye lens 7A, and the exit surface of each lens element 7a of the fly-eye lens 7A is The same number of light source images (here 3 XI 2) as the number of lens elements constituting 30 are formed with a small loss of light. In this configuration, since the illuminance distribution on the entrance surface of the subsequent fly-eye lens 7A is more uniform than in the single fly-eye lens configuration, the transmittance of the filter 100A disposed on the entrance surface of the fly-eye lens 7A is It is easy to set the distribution with high accuracy.

 In addition, in the double fly-eye lens configuration, each component of a large number of light source images by the optical integrator (fly-eye lens 330) in the front stage formed on the exit surface of the rear fly-eye lens 7A is formed. Therefore, the light intensity distribution of the light beam condensed on the surface to be irradiated can be more finely controlled.

In a step-and-scan type projection exposure apparatus, as a result of integration with respect to the scanning direction, each point is collected at each point on the irradiated surface. W

24 It is only necessary that the light intensity distribution of the luminous flux has a desired shape. Conversely, for each point on the surface to be illuminated, for each point arranged in a direction perpendicular to the scanning direction, the light intensity distribution in the converged light beam can be set independently. However, at each point arranged in the scanning direction, the light intensity distribution in the converged light flux is completely the same because it is superimposed by scanning.

 In a step-and-repeat type projection exposure apparatus, in particular, the light intensity distribution on the optical Fourier transform surface with respect to the irradiated surface is made to be rotationally symmetric about the optical axis as an example. Is preferred.

 Further, in the above-described embodiment, the exit surface of the fly-eye lens 7 in FIG. 1 is regarded as a pseudo surface light source (denoted as “secondary light source”) to configure the cellular illumination. Here, when the emission surface of the fly-eye lens 7 is viewed again as a light source, it can be seen that the primary light source is equivalent to the number of lens elements constituting the fly-eye lens 7 arranged vertically and horizontally.

 The intensity ratio of each primary light source forming this surface light source can be arbitrarily set by changing the transmittance of the corresponding lens element. Since it is somewhat difficult to actually process the lens element itself, an illumination correction filter 200 is arranged near the entrance surface or the exit surface of the fly-eye lens 7 and the transmittance is changed. Is preferred. In this case, the entrance surface of each lens element of the fly-eye lens 7 is conjugate to the reticle 13 and the wafer 18 respectively, and each point in the entrance surface of the lens element is individually associated with each point on the wafer surface. Considering that there is a corresponding relationship, as shown in FIG. 1, if the illuminance correction filter 200 is arranged near the entrance surface of the fly-eye lens 7, that is, near the filter 100, It is possible to independently control the light intensity distribution of the light beam focused on each point on the image plane.

In the above, the projection exposure apparatus and the illumination apparatus of the present example have been described. Hereinafter, a method for manufacturing a device using the projection exposure apparatus will be described.

 First, in FIG. 1, for example, an unexposed wafer for evaluation is placed on the wafer stage WST, and the wafer stage WST is moved by a predetermined amount in the optical axis direction of the projection optical system 14. The focus position (best focus position) where the best pattern is formed is determined by exposing the pattern image of the reticle for evaluation while shifting the WST in the X and Y directions and measuring the shape of the pattern after development. Execute the focusing process. Then, after this focusing step, the process shifts to an exposure step (photolithography). In this exposure step, a reticle setting step of setting the reticle 13 on the object plane of the projection optical system 14, a wafer setting step of setting a wafer 18 as a photosensitive substrate on the image plane of the projection optical system 14 An alignment step of aligning the reticle 13 with the wafer 18, and illuminating the reticle 13 with an illumination optical system including the light source 1 and the second condenser lens group 11, and forming a pattern image of the reticle 13. A transfer step of projecting and exposing each shot area on the wafer 18 via the projection optical system 14.

After the above-described exposure process (photolithographic process), the wafer 18 is subjected to an etching process of performing an etching process using the resist pattern remaining after the development process as a mask, and an unnecessary resist after the etching process. It goes through a resist removing step for removing. Then, the steps of exposure, development, etching, and resist removal are repeated to complete the wafer process. When the wafer process is completed, in the actual assembly process, a dicing process in which the wafer is cut into chips for each baked circuit, a bonding process in which wiring is performed on each chip, and a packaging process in which each chip is packaged. Finally, semiconductor devices such as LSIs are manufactured through a packaging process and the like. In the above description, an example of manufacturing a semiconductor device such as an LSI by a photolithography process in a wafer process using an exposure apparatus has been described. However, a liquid crystal display element and a thin film magnetic device can be manufactured by a photolithography process using an exposure apparatus. We can also manufacture semiconductor devices such as heads and image sensors (CCD, etc.). Example of the first embodiment

 Hereinafter, two specific examples of the transmittance distribution of a filter that can be used as the filter 100 in the projection exposure apparatus of the first embodiment of FIG. In the following examples, for easy understanding, both the illuminance distribution adjustment amount and the light intensity adjustment amount of the light beam to be condensed use simple shapes. It is possible to generate a complex light intensity distribution.

 [First Example of First Embodiment]

 FIG. 6A is a diagram showing a filter 100B according to the first embodiment of the present invention. In FIG. 6A, directions corresponding to the X direction and the Y direction in FIG. And Here, the projection exposure apparatus of FIG. 1 is of a step-and-repeat type (stepper type). Filler 100B in FIG. 6 (a) can be set to the entrance surface of fly eye lens 7 instead of fill lens 100 in FIG. Are divided into a number of rectangular filter elements 101 A, 102 A, 103 A, etc. in the X direction and the Y direction orthogonal to each other according to the number of lens elements constituting. Each of these filter elements has a continuously changing transmittance distribution.

That is, Fig. 6 (b) shows the transmittance distribution along the BB line in Fig. 6 (a), and the horizontal axis in Fig. 6 (b) is the position in the X direction along the BB line, and the vertical axis is the position X. You 2 shows a transmittance distribution T (X) of the sample. In addition, the transmittance distribution on the plane that cuts FIG. 6 (a) in the Y direction also changes continuously as in FIG. 6 (b). For the sake of simplicity, it is assumed that the fly-eye lens 7 is composed of a total of 25 lens elements of 5 rows × 5 columns, and accordingly the filter 100 B also has 5 rows X It is divided into five columns of fill elements. Further, for simplicity, the filter 100B is drawn without a component for compensating the light intensity distribution on the irradiated surface (the pattern surface of the reticle 13 in FIG. 1). In other words, the transmittance distribution of the filter 100 B shows only the components based on the request for controlling the coherence factor.

Each fill element 100 A, 102 A, 103 A, etc. of the fill element 100 B corresponding to each lens element of the fly-eye lens 7 has a transmittance distribution (density distribution) therein. By changing each filter element, when combined with the fly-eye lens 7, the light intensity distribution (illumination numerical aperture NA _IL ) with respect to the incident angle of the illuminance light at each position on the surface to be irradiated, and consequently The coherence factor (σ value) can be changed. According to this example, since the transmittance distribution of the filter element in the filter 100Β is not a discrete change but a continuous change, the change in the coherence factor at each position on the irradiated surface is changed. Can be continuous. The same applies to the light intensity distribution on the irradiated surface. The illuminated surface and, consequently, the image surface on which it is projected and exposed, for example, the line width of the projected image of the device pattern on the surface of the wafer 18 in FIG. 1, especially in this example, the isolated pattern whose line width varies depending on the coherence factor The line width can be controlled continuously by the filter 100 designed so. Therefore, the line width of the projected image can be controlled to the target line width regardless of the image height, and the line widths of the images of the patterns arranged in different directions at the same image height can be controlled to the target line widths. it can.

In the case of a step and repeat type projection exposure apparatus, The tendency of the change in the line width of the projected image is expected to change axially with respect to the optical axis AX of the projection optical system 14. Thus, when the change in the line width of the projected image is axisymmetric, the change in the transmittance of each lens element of the fly-eye lens 7 of the filter 100B for controlling the change is also caused by the light of the illumination optical system. It is set to be axisymmetric with respect to the axis.

 [Second Example of First Embodiment]

 FIG. 7A is a diagram showing a filter 110 according to the second embodiment of the present invention. In FIG. 7A, directions corresponding to the X direction and the Y direction in FIG. Direction. Here, the projection exposure apparatus of FIG. 1 is of a step-and-scan method. The filter 110 in FIG. 7 (a) can also be arranged on the entrance surface of the fly-eye lens 7 instead of the filter 100 in FIG. In accordance with the lens element, the filter element is divided into a number of rectangular filter elements 111, 112, etc., each having a width in the X direction of HX1 and a width in the Y direction of HY1.

 In the step-and-scan method, the pattern surface of the reticle 13 in FIG. 1 is illuminated by an elongated rectangular illumination area 54 in the X direction as shown in FIG. 7 (b). Reticle 13 is scanned in the + Y direction (or one Y direction) with respect to 54, and in synchronization with this, wafer 18 in FIG. 1 is scanned in the one Y direction (or + Y direction). That is, the running direction is the Y direction, and the direction corresponding to the scanning direction on the filter 110 in FIG. 7A is also the Y direction.

In this case, the shape of the illumination area 54 is finally determined by the field stop 10 in FIG. 1, but in order to increase the illumination efficiency, the shape of the illumination area 54 is the maximum illumination area by the fly-eye lens 7. It is desirable that they have almost the same shape. Further, the entrance surface of each lens element of the fly-eye lens 7 is conjugate with the arrangement surface of the illumination area 54. Therefore, each lens of fly eye lens 7 The cross-sectional shape of the element in the X direction, HX 1, and the width in the Y direction, HY 1, is a rectangle elongated in the X direction that is almost similar to the illumination area 54. Therefore, assuming that the width of the illumination area 54 in the X direction is HX2 and the width in the Y direction is HY2, the following equation is substantially satisfied.

 HX 1: XY 1 ^ HX2: HY2 (1)

 In this example, HX1: XY1 = 3: 1. Also, the filter elements 1 1, 1 1 2, etc. of the filter 110 in FIG. 7 (a) each have a transmittance distribution that changes continuously.

 That is, Fig. 7 (c) shows the transmittance distribution along the CC line in Fig. 7 (a) .The horizontal axis in Fig. 7 (c) is the position in the X direction along the CC line, and the vertical axis is the position X. The transmittance distribution T (X) is shown. For the sake of simplicity, it is assumed that the fly-eye lens 7 is composed of a total of 27 lens elements in 9 rows (Y direction) and 3 columns (X direction). E 110 is also divided into nine rows and three columns of filter elements. Further, for the sake of simplicity, the transmittance distribution of the filter 110 is also drawn by omitting a component for compensating the light intensity distribution on the irradiated surface.

 By combining the filter 110 with the continuous transmittance distribution shown in Fig. 7 (a) and the fly's eye lens 7, the line width of the projected image of the pattern of the reticle 13 can be set to the target regardless of the image height. The line width of the projected image of the pattern arranged at the same image height in different directions can be controlled to the target line width.

 [First Modification of Second Embodiment]

Fig. 8 (a) shows one of the filter elements 1 2 1 that can be set in the illumination optical system of the step-and-scan type projection exposure apparatus instead of the filter 110 of the second embodiment. FIG. 8 (a) is an enlarged view showing directions corresponding to the X direction and the Y direction in FIG. 1 as the X direction and the Y direction, respectively. I have. Also in this example, since the pattern surface of the reticle 13 is illuminated by the elongated illumination area 54 shown in FIG. 8B, the width HX 1 in the X direction and the width HY 1 in the Y direction of the filter element 1 2 1 Equation (1) holds, and the Y direction is the direction corresponding to the running direction.

 As shown in Fig. 8 (a), the filter element 1 2 1 is divided into five regions 51, 52 A, 52 B, 53 A, 53 by the boundary line intersecting in the scanning direction. It is divided into B, and the transmittance distribution is constant in each of these regions. Specifically, the transmittance gradually decreases from the central region 51 to the outer regions 52A and 52B, and further to the outer regions 53A and 53B.

 In the step-and-scan method, the illuminance in the scanning direction (Y direction) of the slit-shaped illumination area 54 is averaged during the actual exposure operation. Therefore, it is not particularly necessary to provide a continuous transmittance distribution in advance for each lens element of the fly-eye lens 7 corresponding to the surface to be irradiated, and as shown in FIG. Due to the averaging effect in the scanning direction, the light amount distribution after scanning exposure is equivalent to the case of using a filter with a continuous transmittance distribution even if it is a typical transmittance distribution (density distribution). become.

 In this case, from the viewpoint of symmetry, the transmittance in three stages is shown in Fig. 8 (a), but the five regions 51, 52A, 52B, 53A, 53B are all Generalization to set different transmittances is also possible. Now, when the illumination light from the filter element 1 2 1 in FIG. 8A is integrated in the scanning direction (Y direction), it is perpendicular to the scanning direction (X direction), that is, perpendicular to the scanning direction on the irradiated surface. The illuminance distribution seen on a simple line segment is equivalent to illumination light with a coherence factor that changes continuously. Therefore, the line width of the projected image can be controlled to the target value. <[Second Modification of Second Embodiment]

FIG. 9 is an enlarged view showing a filter element 131, which can be used in place of the filter element 1 2 1 in FIG. 8 (a). This is one of the filter elements that can be set in the illumination optical system of a top-and-scan projection exposure apparatus.

 As shown in FIG. 9, the filter element 1 31 is divided into five regions 55, 56A, 56B, 57A, 57B by a boundary line intersecting in the scanning direction. The transmittance distribution is constant in each region. Each of these areas has a shape that is symmetric not only in the non-scanning direction but also in the scanning direction. Specifically, from the central area 55 to the outer areas 56 A and 56 B, and further to the outer areas The transmittance decreases stepwise to the areas 57 A and 57 B of. The characteristic obtained by integrating the transmittance of the filter element 1 3 1 in the Y direction is the same as the characteristic obtained by integrating the transmittance of the filter element 1 2 1 in the Y direction in FIG. 3 1 can be used in place of the fill element 1 2 1.

 The transmittance distribution pattern of the entire filter when the filter element 13 1 in FIG. 9 is used is closer to the transmittance distribution of the second embodiment in FIG. Therefore, according to the illumination method using the filter element 131, the transmittance distribution is continuously changed not only in the scanning exposure but also in the step-and-repeat static exposure. It is possible to obtain an effect closer to that of the different lighting methods.

[Second embodiment]

 Next, a second embodiment of the present invention will be described. Although the projection exposure apparatus shown in FIG. 1 is used in the second embodiment, its basic configuration and operation are the same as those in the first embodiment, and a description thereof will be omitted.

In the projection exposure apparatus of FIG. 1 according to the second embodiment, the transmittance distribution of each filter element of the filter 100 is set to an arbitrary distribution independently for each lens element constituting the fly-eye lens 7. It can be set, but the fly algorithm is used to facilitate calculations in the algorithm that optimizes the transmittance change. Considering that each filter element of the eye lens 100 is divided into a plurality of regions, a method of giving a predetermined optimized transmittance to each of the divided regions can be used.

 As described above, this filter 100 adjusts the coherence factor (σ value) of the illuminating light by the transmittance distribution (shading) of each filter element of the filter 100, and adjusts a portion on the irradiated surface. It is intended to control the line width of the projected image of the pattern to be exposed by giving a coherence factor that is adjusted in a controlled manner. However, the adjustment of the force coherence factor is basically performed only by partially reducing the amount of light by the filter 100. This means a loss of illumination light amount, and this loss of illumination light amount is a side effect of line width adjustment by the filter 100.

 Therefore, in this example, in addition to the fill aperture 100, an aperture stop 8 (that is, a so-called “aperture stop”) that defines the coherence factor of the illumination light by adding it to an optical integrator such as a fly-eye lens is provided. ). Specifically, a device such as a normal semiconductor integrated circuit mainly has a linear pattern extending in one direction (for example, a line 'and' space pattern) and a linear pattern extending in a direction orthogonal thereto. Of the projected image to be adjusted, the difference between the average line width between the projected images of the linear patterns extending in the orthogonal direction and the line of the other pattern They can be roughly divided into width differences. Therefore, the difference in average line width between the projected images of the linear patterns extending in the orthogonal direction is corrected by making the shape of the aperture of the aperture stop 8 non-axially symmetric. It is assumed that only the component is corrected by the filter 100. Thus, loss of illumination light can be reduced.

Hereinafter, a specific example of a transmittance distribution of a filter which can be used as the filter 100 in the projection exposure apparatus of FIG. 1 corresponding to the second embodiment, Specific examples of the aperture shape of the aperture stop 8 will be described. In the following embodiments, a simple shape is used for both the illuminance distribution adjustment amount and the light intensity adjustment amount of the light flux to be condensed so that it is easy to understand. It is possible to generate a complex light intensity distribution of the light beam.

 FIG. 10 (a) is a perspective view showing the filter 100A, the fly-eye lens 7A, and the aperture stop 8 of this example. In FIG. 10 (a), the incident surface of the fly-eye lens 7A is shown. A 100 A filter is installed, and an aperture stop 8 is installed on the exit surface of the fly eye 7 A. The filter 100 A to the aperture stop 8 are installed and used instead of the members from the filter 100 to the aperture stop 8 in FIG. In FIG. 10A, the filter 10 OA and the aperture stop 8 are shown separated from each other along the optical axis of the illumination system for the sake of simplicity. The corresponding directions are the X and Y directions, respectively.

 Further, in this example, the projection exposure apparatus of FIG. 1 is of a step-and-scan method. In this case, the fly-eye lens 7A is a bundle of rectangular cross-sectional lens elements 7a having a width of XXI in the X direction and a width of HY1 in the Y direction, 12 rows in the Y direction and 3 columns in the X direction. It is configured. Then, the filter 10 OA is composed of a number of rectangular filters having a width in the X direction HX 1 and a width in the Y direction HY 1 according to the number of lens elements 7 a constituting the fly-eye lens 7 A. Elements are divided into 1 3 1 etc.

In the step-and-scan method, the surface of the reticle 13 in FIG. 1 is illuminated by a rectangular (slit-shaped) illumination area 54 elongated in the X direction, as shown in FIG. 10 (b). At the time of scanning exposure, the reticle 13 is scanned in the + Y direction (or −Y direction) with respect to the illumination area 54, and in synchronization with this, the wafer 18 in FIG. 1 is scanned in the −Y direction (or + Y direction). You. That is, the running direction is the Y direction, and the fly-eye lens 7A and the fly-eye lens 7A shown in FIG. The direction corresponding to the scanning direction on the filter 100A is also the Y direction.

 In this case, the shape of the illumination area 54 is finally determined by the field stop 10 in FIG. 1, but in order to increase the illumination efficiency, the shape of the illumination area 54 is the maximum illumination area by the fly-eye lens 7 mm. It is desirable that they have almost the same shape. Further, the entrance surface of each lens element of the fly-eye lens 7A is conjugate with the arrangement surface of the illumination area 54. Therefore, the cross-sectional shape of each of the lens elements 7a of the fly-eye lens 7A in the X direction width HX1 and the Y direction width HY1 is a rectangular shape elongated in the X direction substantially similar to the illumination area 54. Therefore, assuming that the width of the illumination area 54 in the X direction is HX 2 and the width in the Y direction is HY 2, the following equation is substantially satisfied.

 HX 1: XY 1 = HX 2: HY 2 (2)

 The pattern formed on the reticle 13 scanned with respect to the illumination area 54 is mainly a linear pattern extending in the non-scanning direction (X direction) (hereinafter, referred to as “horizontal pattern”). It consists of an RPH and a linear pattern (hereinafter referred to as a “vertical pattern”) RPV extending in the scanning direction (Y direction). Then, the difference in average line width between the projected image of the horizontal pattern RPH and the projected image of the vertical pattern RPV is corrected by the shape of the aperture 8a of the aperture stop 8 in FIG. 10 (a).

 In this case, the projection image of the horizontal pattern RPH and the projection image of the vertical pattern RPV are used with an aperture stop having a normal circular aperture (corresponding to the circular aperture 8f in Fig. 11 (b)). It is assumed that the difference between the line widths is as shown in FIG. 12 as an example.

In FIG. 12, the horizontal axis is a position Y in the scanning direction in the illumination area 54 in FIG. 10B, and the vertical axis is the position Y on the wafer via the projection optical system 14 in FIG. 1. This is the line width d _CK of the projected image of the pattern having a predetermined reference line width (Critical Dimension). In Fig. 12, curve H is the reference line width. The line width of the projected image of RPH, the curve V represents the line width of the projected image of the vertical pattern RPV of the reference line width, and the line width d _{CR of the} projected image is wider for the horizontal pattern RPH I'm sorry.

 In general, when the coherence factor (high value) of the illuminating light applied to the pattern to be transferred is increased, the line width of the projected image of the pattern decreases as shown by the curve in FIG.

In FIG. 13, the horizontal axis indicates the σ value, and the vertical axis indicates the line width d _CR of the projected image of the isolated line having the reference line width projected at the σ value. The reference line width is the reference line width in the assumed process. Curves of Figures 1 to 3, the use of illumination light of a large σ value, the line width d _CR of the projected image becomes thin, the control of the line width is meant to be a possible. Therefore, in order to correct the difference between the line widths of the projected images of the horizontal pattern RPH and the vertical pattern RPV shown in FIG. 12, the σ value of the illumination light for the horizontal pattern RPH is changed to the illumination light for the vertical pattern RPV. It can be seen that the value should be set to be larger than the σ value.

Therefore, as a procedure for setting the σ value by the aperture stop 8, first, an average line width difference ΔdcR in the illumination area, which is an average difference between the curves Η and V in FIG. By applying the width difference △ d _CR to Fig. 13, the difference Δ σ between the σ value of the aperture 8a of the aperture 8 in the X direction and the σ value of the Just ask. As a result, the opening 8a is set to an elliptical shape with the optical axis as the center and the long axis in the Y direction.

FIG. 11 (b) shows the relationship between the aperture stop 8 and the fly-eye lens 7A. In FIG. 11 (b), the aperture stop 8 when the line width difference shown in FIG. Assuming that the opening of the circular opening 8 f is a circular opening 8 f having a diameter φ D 2, the opening 8 a for correcting the average line width difference △ d _CR in FIG. 12 is the diameter of the circular opening 8 f in the Y direction, The length is set to 1 by increasing the length corresponding to the difference Δ σ to the diameter 2. As a result, the aperture 8a is With the optical axis AXI as the center, the width in the short axis direction (X direction) is 2 and the width in the long axis direction (Υ direction) is (iD1) elliptical.

 Contrary to the example of FIG. 12, when the resolution of the projected image of the vertical pattern RPV is lower than that of the horizontal pattern RPH in a state where the aperture stop having a normal circular aperture is used, the aperture stop 8 is used. As shown in Fig. 11 (c), an elliptical opening 8b long in the X direction with respect to the optical axis AXI may be provided. That is, the diameter 4 in the X direction of the opening 8b is set to be longer than the diameter 3 in the Y direction by a length corresponding to the difference in σ value to be corrected.

 Next, the variation component of the line width of the projected image at each position in the illumination area 54 for each of the horizontal pattern RPH and the vertical pattern RPV in FIG. 10 (b) is calculated by the filter 10 OA in FIG. 10 (a). to correct.

For example, when considering the horizontal pattern RPH, first, the width of the illumination region 54 in the scanning direction (Y direction) is divided into a predetermined number, and the line of the projected image of the horizontal pattern RPH having the reference line width is divided for each divided region. _Find the average value of width d _CR . Next, with respect to the average line width of the projected images of the horizontal and vertical patterns obtained above (corresponding to the average value of the curve V in FIG. 12), the line width d _CR of the projected image for each of these divided regions is given. determination of the difference (5 d _CR. Then, for example, from 1 3, we obtain the correction amount delta Shigumaita of σ values for correcting the difference [delta] d _CR of the line width d _CR for each area that are each divided.

Next, similarly, for the vertical pattern RPV, the average value of the line width d _CR of the projected image of the vertical pattern RPV is calculated for each of the divided areas of the illumination area 54. Then, calculated relative to the average line width of the projected image determined previously (average of 1 second curve V), the difference [delta] d _CR their line width d _C R of the projected image of each divided each region, For example, from FIG. 13, the correction amount Δσ V of the σ value for correcting the difference dd _CR of the line width d _CR is obtained for each of the divided areas.

The pattern to be transferred obtained in this manner is divided in the scanning direction. The correction amounts Δσ H and Δσ ν of the σ value for each section and for each direction are replaced with the transmittance distribution (density distribution) for each fill element of fill 100 1. For this purpose, the transmittance distribution of each filter element may be optimized by balancing with the intensity unevenness of the illumination light that changes due to the filtering of each filter element.

 Fig. 11 (a) shows an example of the transmittance distribution of each filter element of the filter 10OA determined in this way. In Fig. 11 (a), the fly-eye lens 7A The filter 100A is also divided into 12 rows and 3 columns of filter elements corresponding to each lens element 7a. In this example, as an example, each filter element is divided into three regions in the X direction, and a predetermined transmittance (density) is given to each of the divided regions independently of each other. Specifically, the non-hatched area 14 1 has a transmittance of approximately 100%, the hatched area 14 2 has a reduced transmittance, and the double-hatched area has double transmittance. The region 1 43 applied is the region having the lowest transmittance. For example, the filter element 13 1 in the first column and the first row is composed of the areas 14 1 and 14 2, and the filter element 13 2 in the first column and the second row is the area 14 The filter element 1 3 3 in the third column and the third row is composed of 1 and 1 4 3 The filter element 1 3 4 in the third column is composed of the areas 1 4 1 and 1 4 2 Has a total transmittance of about 100%, and the filter element 1 35 in the third column and the fifth row is composed of regions 14 1 and 14 2.

 By using such a filter 100 A and the aperture stop 8, the line width of the projected image of the reticle 13 pattern can be controlled to the target line width regardless of the image height, and the same image width can be obtained. The line widths of the projected images of the patterns arranged at different heights in different directions can be controlled to target line widths.

In the second embodiment, the present invention is applied to a step-and-scan type projection exposure apparatus. Even when applied to a projection repeater of the batch repeat type (batch exposure type), the line width of the projected image between the horizontal pattern and the vertical pattern can be obtained by making the aperture shape of the aperture stop 8 non-axisymmetric. Can be corrected, and the remaining component of the line width difference can be corrected by the filter 100 or the like.

 In the second embodiment, the aperture of the aperture stop 8 before correction is circular. For example, Japanese Patent Application Laid-Open No. 5-175101 and the corresponding US Pat. As disclosed in Japanese Patent No. 76801, even when the aperture before correction of the aperture stop 8 is, for example, a ring-shaped aperture, the present invention is applied to make the ring-shaped aperture non-axisymmetric, For example, at least one of the inner diameter and the outer diameter may be an elliptical annular opening. Also, as disclosed in, for example, Japanese Patent Application Laid-Open No. 6-42521 and corresponding US Pat. No. 5,335,444, an aperture stop for deformed illumination comprising a plurality of small apertures. Also, the arrangement of the small openings may be made non-axisymmetric, or each small opening may be made elliptical. To the extent permitted by the laws and regulations of the designated country designated in this international application or of the selected elected country, the disclosure of the above-mentioned gazettes and US patents shall be incorporated herein by reference.

In the second embodiment, the intensity distribution (secondary light source) of the exposure light on the Fourier transform plane in the illumination optical system is defined to be elliptical by using an aperture stop having an elliptical aperture. The optical element that defines the elliptical intensity distribution is not limited to the aperture stop. For example, a cylindrical lens or a toric lens may be arranged in the illumination optical path so as to be insertable and removable from the light source side of the optical integrates, so that the above-described intensity distribution is defined as an ellipse. In the above-described embodiment, the surface light source composed of a plurality of light source images, that is, the secondary light source is formed on the Fourier transform surface by the fly-eye lens, but is formed on the incident surface side in the case of Rod Integre. The secondary light source is defined by a plurality of virtual images. Further, in order to change the above-mentioned coherence factor (high value) or to realize annular illumination or deformed illumination, that is, to change the intensity distribution of exposure light on the Fourier transform plane in the illumination optical system. Although a plurality of aperture stops having different aperture shapes or sizes are used, at least one optical element disposed between the exposure light source and the optical It may be configured to move to change the intensity distribution (σ value) of the illuminating light on the incident surface at the optical integre.

 In addition, a pair of conical prisms (axicons) is further disposed on the light source side than at least one of the optical elements, and the interval of the pair of axicons in the optical axis direction is adjusted, so that the optical integrator can enter the optical integrator. The illumination light on the surface may be configured to be changeable into a ring shape in which the intensity distribution is higher outside the center than outside the center. As a result, in the fly-eye lens, the intensity distribution of the illumination light on the exit-side focal plane and, in the case of the rod integrator, on the Fourier transform plane of the illumination optical system set between the exit plane and the reticle. In addition to being able to change the light amount, the loss of the amount of illumination light due to the change in the illumination conditions can be greatly reduced, and high throughput can be maintained.

 When performing deformed illumination, as an example, a ring-shaped intensity distribution is generated on the incident surface of the fly-eye lens by a pair of axicons, and an optical element having a cross-shaped light-shielding portion or a darkening portion is connected to the fly-eye lens. It may be disposed on the exit side focal plane (Fourier transform plane) of the lens or in the vicinity thereof.

In addition, the aperture of the aperture stop 8 may be a non-axisymmetric image having a step-like contour following the light source image formed by the optical integrator (fly-eye lens) or the arrangement of each lens element of the fly-eye lens. ₍ Note that the present invention is not limited to the projection exposure apparatus of the above-described embodiment, but also includes a mask pattern that is brought into close contact with a substrate without using a projection optical system. Can also be applied to a proximity exposure apparatus that exposes the light.

 Further, when a projection optical system is used, the magnification of the projection optical system may be not only a reduction system but also an equal magnification or an enlargement system. Further, the projection optical system may be any one of a dioptric system including only a plurality of dioptric optical elements, a reflecting system including only a plurality of reflective optical elements, and a catadioptric system combining a dioptric optical element and a reflective optical element. As a catadioptric optical system, for example, as disclosed in US Pat. No. 5,788,229, a plurality of refractive optical systems and two catoptric optical elements (at least one of which is a concave mirror) are bent. The optical system may be arranged on an optical axis that extends in a straight line without any restriction, and the disclosure of this U.S. patent is incorporated by reference, as far as allowed by the designated countries specified in this international application or the national laws of the selected selected countries. Part of the text.

 Note that reversing the transmittance distribution between the filter element 102 at the center of the filter 100 shown in Fig. 4 and the filter element at the periphery, etc. No. 9-1 6 1 579 (Japanese Unexamined Patent Publication No. Hei 10-31 9 321) and corresponding U.S. patent application No. 0 4 2 4 3 4

(Filing date: March 13, 1998), and as far as the national laws of the designated country designated in this international application or the chosen elected country allow, the The disclosure is incorporated herein by reference. Also, instead of providing a filter 100 separately from the fly-eye lens 7, the entrance surface of the fly-eye lens 7 is provided with the above-described transmittance distribution so that the fly-eye lens 7 also serves as the filter. You may. Further, instead of the double fly eye lens, a double fly eye lens (fly fly eye lens) and a rod fly eye lens may be arranged in series.

In addition, the illumination light for exposure may be a single infrared or visible region oscillated from a DFB (Distilled feedback) semiconductor laser or fiber laser. A wavelength laser is amplified by, for example, a fiber amplifier doped with erbium (Er) (or both erbium and ytterbium (Yb)), and is subjected to wavelength conversion to ultraviolet light using a nonlinear optical crystal. Waves may be used. As an example, if the oscillation wavelength of a single-wavelength laser is within the range of 1.544 to 1.553 m, then at the 8th harmonic, light with a wavelength of 193 to 194 nm, that is, almost the same as an ArF excimer laser ultraviolet light is obtained as a wavelength substantially the same when the oscillation wavelength 1. and 57 to 1.58 in the range of xm, 1 0 times the light of the wavelength 1 57~ 1 5 8 nm in harmonic, i.e. the F ₂ laser Ultraviolet light having the wavelength is obtained.

Further, the present invention can be applied not only to an exposure apparatus used for manufacturing a micro device such as a semiconductor element, but also to an exposure apparatus used for manufacturing a mask or a reticle. In a mask or reticle manufacturing process using an exposure apparatus to which the present invention is applied, for example, an enlarged pattern of a device pattern to be formed on a reticle is divided into a plurality, and each of the divided parent patterns is formed on a master reticle. . Then, a reduced image of the parent pattern formed on a plurality of masks is transferred onto a transparent substrate serving as a reticle to form one device pattern. In a projection exposure apparatus for manufacturing a device using far ultraviolet light or vacuum ultraviolet light, a transmission type reticle is generally used.Therefore, a reticle substrate is made of quartz glass, fluorine-doped quartz glass, Fluorite, magnesium fluoride or quartz is used. Also, in an exposure apparatus using a soft X-ray region generated from a laser plasma light source or SOR (Syncron Orbital Radiation) ring, for example, EUV (Extreme Ultraviolet) light with a wavelength of 13.4 nm or 11.5 nm. A reflection type mask is used, and a proximity type X-ray exposure apparatus or an electron beam exposure apparatus uses a transmission type mask (stencil mask, membrane mask, etc.). For example, ehachi is used.

 Then, an illumination optical system and a projection optical system composed of a plurality of lenses are incorporated in the main body of the exposure apparatus for optical adjustment, and a reticle stage and a wafer stage composed of many mechanical parts are attached to the main body of the exposure apparatus to perform wiring and distribution. The exposure apparatus of the present embodiment can be manufactured by connecting the tubes and performing overall adjustment (electrical adjustment, operation confirmation, etc.). It is desirable to manufacture the exposure equipment in a clean room where the temperature and cleanliness are controlled.

 It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention. It also contains the description, claims, drawings, and abstracts of Japanese Patent Application No. 10 _ 7452, filed January 19, 1998, and 1998 The entire disclosure content of Japanese Patent Application No. 10-38960 filed on May 20 is incorporated herein by reference in its entirety. Industrial applicability

 According to the first or second illuminating device of the present invention, since the filter element composed of the filter elements having the transmittance distributions independent of each other is used, the image of the illuminated object is converted into a predetermined image forming system. When the projection is performed by using, there is an advantage that a projection image of a target line width can be obtained at different positions on the image plane or for patterns arranged in different directions.

 In addition, the transmittance distribution in each filter element changes substantially continuously, or the illuminance distribution after scanning changes substantially continuously, so that the continuously changing coherence factor gives There is an advantage that a projected image can be projected with high accuracy at a target line width at any position on the image plane.

According to the third or fourth lighting device of the present invention, the non-axisymmetric aperture The combination of an aperture stop having the following formula and a predetermined filter can optimize the coherence factor for each point on the illuminated surface, and when projecting an image of the illuminated object with a predetermined imaging system, There is an advantage that a projection image of a target line width can be obtained even at different positions on the image plane or for patterns arranged in different directions.

 In addition, since the coherence factor is adjusted twice for the aperture stop and the filter, the loss of illumination light due to the filter can be reduced, and the throughput when applied to the illumination optical system of an exposure apparatus Can be improved. Furthermore, since the transmittance of each filter element that composes the filter can be increased (only a low density is required), it is possible to reduce the amount of deviation of the transmittance distribution from the optimal distribution that occurs when the lighting conditions are changed. it can. This also has the advantage of reducing line width errors due to lighting conditions, ie, process specificity.

 Further, according to the first, second, third or fourth exposure apparatus of the present invention, or the first or second exposure method of the present invention, the step-and-repeat method or the step リThe projection image (or transfer image) of the target line width can be obtained at different positions on the image plane (or transfer image) by the AND 'scan method or the like, or for patterns arranged in different directions. There are advantages that can be obtained.

 Next, according to the device manufacturing method of the present invention, a high-performance device having a target line width pattern can be manufactured using the projection exposure apparatus. Further, according to the method of manufacturing an exposure apparatus of the present invention, the exposure apparatus of the present invention can be easily manufactured.

Claims

Range of request 1. A light source system that supplies the illumination light, an optical integrator that forms a plurality of light source images from the illumination light from the light source system, and a light beam from the plurality of light source images is condensed to superimpose the irradiated surface. Illuminator with a condenser optical system that illuminates  A filter is disposed at or near a position optically conjugate to the irradiated surface, and the filter is divided into a plurality of regions corresponding to the plurality of light source images, respectively. Filter elements are provided, each having an independent transmittance distribution.  The plurality of filter elements provided in the plurality of regions independently set the light intensity distribution on the optical Fourier transform surface for each of the minute surfaces constituting the irradiated surface to a predetermined light intensity distribution. A lighting system characterized by having a substantially continuously varying transmittance distribution for each.  2. A light source system that supplies the illumination light, an optical integrator that forms a plurality of light source images from the illumination light from the light source system, and a light beam from the plurality of light source images is condensed to overlap the illuminated surface. And a condenser optical system that illuminates  An illumination device for illuminating an object to be illuminated moving in a predetermined scanning direction, wherein a filter is disposed at or near a position optically conjugate to the surface to be illuminated; Each of the light source images is divided into a plurality of regions corresponding to the light source images, and the plurality of regions are provided with filter elements each having a transmittance distribution independent of each other. At least a part of the plurality of filter elements provided in the plurality of regions is configured such that a light intensity distribution on an optical Fourier transform surface with respect to each minute surface constituting the irradiated surface is independently determined as a predetermined light intensity distribution. To set An illumination device, wherein the illumination device is divided into a plurality of partial regions each having a different transmittance from each other, and a boundary line between the plurality of partial regions is inclined with respect to the predetermined scanning direction.  3. The illumination according to claim 1, wherein the optical integrator has a plurality of lens elements, and the filter is arranged on an incident side of the optical integrator. apparatus.  4. A second optical integrator and a second condenser optical system are arranged between the light source system and the optical integrator. The lighting device according to the above.  5. The illuminance distribution correction filter for uniformizing the illuminance distribution on the surface to be illuminated is disposed near the filter. Lighting equipment.  6. A light source system that supplies the illumination light, an optical integument that forms a plurality of light source images from the illumination light from the light source system, and a light flux from the plurality of light source images condensed to superimpose the irradiated surface. An illumination device having a condenser optical system for illuminating the optical system,  A filter is disposed at or near a position optically conjugate to the irradiated surface, and the filter is divided into a plurality of regions corresponding to the plurality of light source images, respectively. A filter element having a transmittance distribution independent of each other is provided.  Each transmittance distribution of the plurality of filter elements provided in the plurality of regions is obtained by independently converting a light intensity distribution on an optical Fourier transform surface with respect to each minute surface constituting the irradiated surface to a predetermined light intensity. Is set to be set to the distribution, An aperture stop having a non-axisymmetric aperture is disposed on an optical Fourier transform surface with respect to the irradiated surface or on a surface in the vicinity thereof. Lighting device.  7. The illumination device is an illumination device that illuminates an object to be illuminated moving in a predetermined scanning direction,  7. The illumination device according to claim 6, wherein the shape of the aperture of the aperture stop is an elliptical shape whose major axis direction or minor axis direction is a direction corresponding to the scanning direction with the optical axis as a center.  8. The optical integrator has a plurality of lens elements, and the filter is disposed on an incident side of the optical integrator, and  8. The illumination device according to claim 6, wherein the aperture stop is arranged on an exit side of the optical and integre.  9. The second optical integrator and a second condenser optical system are arranged between the light source system and the optical integrator. Lighting equipment.  10. An illumination distribution correction filter for uniforming the illumination distribution on the irradiated surface is arranged near the filter. The lighting device according to any one of claims 6 to 9.  1 1. The lighting device according to claim 1 or 6,  A mask stage on which a mask as an object to be illuminated is mounted, a projection optical system, and a substrate stage for positioning a substrate onto which a pattern of the mask is transferred,  An exposure apparatus comprising: illuminating the mask with illumination light from the illumination device; and transferring an image of the pattern of the mask onto the substrate via the projection optical system.  1 2. The lighting device according to claim 2 or 7, A mask stage that moves a mask as an illuminated object in a predetermined scanning direction A projection optical system; and a substrate stage for moving a substrate onto which the pattern of the mask is transferred in a direction corresponding to the scanning direction in synchronization with the mask stage,  Illuminating the mask with illumination light from the illumination device, and moving the mask and the substrate in synchronization with the projection optical system via the mask stage and the substrate stage, An exposure apparatus for sequentially transferring a pattern image of a mask onto the substrate.  13. An exposure apparatus having an illumination optical system for irradiating a mask with illumination light, and exposing a photosensitive substrate with the illumination light through the mask.  An optical filter that sets transmittance distributions in a plurality of regions on a surface substantially conjugate with the pattern surface of the mask in the illumination optical system independently of each other;  An optical system that makes each of a plurality of regions on a predetermined surface orthogonal to the optical axis thereof in the illumination optical system substantially have an image-forming relationship with the illumination region on the mask; and An exposure apparatus, wherein the plurality of regions are each provided with a substantially continuously changing transmittance distribution.  14. An exposure apparatus having an illumination optical system for irradiating illumination light to a mask moving in a predetermined scanning direction, and exposing a photosensitive substrate with the illumination light via the mask.  An optical filter having a plurality of filter elements for independently setting transmittance distributions in a plurality of regions on a surface substantially conjugate to a pattern surface of the mask in the illumination optical system; An optical system that makes each of a plurality of regions on a predetermined surface orthogonal to the optical axis thereof in the illumination optical system have an approximately image-forming relationship with an illumination region on the mask, respectively; At least some of the filter elements of the filter element are divided into a plurality of partial areas, each having a different transmittance. The exposure apparatus according to claim 1, wherein a boundary between the plurality of partial regions is inclined with respect to the predetermined scanning direction.  15. The optical system according to claim 1, wherein the optical system includes an optical system and a condenser optical system, and the predetermined surface is set at or near one end surface of the optical integrator. Exposure apparatus according to 3, or 14.  16. The exposure apparatus according to claim 15, wherein the optical ′ integrator is a fly-eye lens, and the predetermined surface is set at or near an incident surface of the fly-eye lens.  17. The exposure apparatus according to claim 13, wherein the optical filter is arranged on the predetermined surface or in the vicinity thereof.  18. The optical system according to claim 18, further comprising an optical member that makes the intensity distribution of the illumination light non-axisymmetric on an optical Fourier transform plane with respect to the pattern of the mask in the illumination optical system. Exposure apparatus according to range 13 or 14. 19. The exposure apparatus according to claim 18, wherein the optical member includes an aperture stop arranged at or near the Fourier transform plane and having a non-axisymmetric aperture.  20. A device manufacturing method for manufacturing a predetermined device using the exposure apparatus according to claim 11 or 12,  Using the mask on which the original pattern of the predetermined device is formed, the mask is illuminated by the illuminating device, and the image of the pattern of the mask should be formed through the projection optical system to form the predetermined device. A method for manufacturing a device, comprising transferring the image onto a substrate. 21. An exposure method for illuminating a mask in a superimposed manner through an optical 'Integral that forms a plurality of light source images from illumination light from a light source system, and transferring a pattern of the mask onto a substrate, A filter is arranged at or near a position optically conjugate to the irradiated surface, and the filter is divided into a plurality of regions corresponding to the plurality of light source images, respectively. A filter element with independent transmittance distribution is provided,  The plurality of filter elements provided in the plurality of regions independently set the light intensity distribution on the optical Fourier transform surface for each of the minute surfaces constituting the irradiated surface to a predetermined light intensity distribution. An exposure method, wherein each of the exposure methods has a substantially continuously changing transmittance distribution.  22. A mask moving in a predetermined scanning direction is superimposedly illuminated through an optical integrity that forms a plurality of light source images from illumination light from a light source system, and the pattern of the mask is transferred onto a substrate. An exposure method, wherein a filter is disposed at or near a position optically conjugate to the pattern surface of the mask, and the filter is divided into a plurality of regions corresponding to each of the plurality of light source images. And a filter element having a transmittance distribution independent of each other is provided in each of the plurality of regions.  At least a part of the plurality of filter elements provided in the plurality of regions is configured such that a light intensity distribution on an optical Fourier transform surface with respect to each minute surface constituting the irradiated surface is independently determined by a predetermined light. In order to set the intensity distribution, it is divided into a plurality of partial regions each having a different transmittance from each other, and a boundary line between the plurality of partial regions is inclined with respect to the predetermined scanning direction. An exposure method comprising:  23. In a method of manufacturing an exposure apparatus for transferring a mask pattern onto a substrate, An illumination optical system for irradiating the mask with illumination light; a stage system for positioning the mask and the substrate; and a plurality of optical systems on a surface substantially conjugate with a mask plane in the illumination optical system. The transmittance distribution in the region An optical filter that is set independently of each other; and an optical system that makes a plurality of regions on a predetermined surface orthogonal to the optical axis thereof in the illumination optical system substantially have an imaging relationship with the illumination region on the mask, respectively. When assembling in a predetermined positional relationship with each other,  A method of manufacturing an exposure apparatus, wherein the optical filter is provided with a transmittance distribution that changes substantially continuously in each of the plurality of regions.  24. In a method for manufacturing an exposure apparatus for transferring a pattern of the mask onto the substrate by synchronously moving a mask and a substrate,  An illumination optical system for irradiating the mask moving in a predetermined scanning direction with illumination light; a stage system for positioning the mask and the substrate; and a substantially conjugate with a pattern surface of the mask in the illumination optical system. An optical filter having a plurality of filter elements for setting transmittance distributions in a plurality of regions on the surface independently of each other; and a plurality of regions on a predetermined surface orthogonal to the optical axis in the illumination optical system. When assembling the optical systems, which are substantially in an imaging relationship with the illumination area on the mask, in a predetermined positional relationship with each other,  At least a part of the plurality of filter elements of the optical filter is divided into a plurality of partial areas each having a different transmittance, and a boundary line between the plurality of partial areas is defined in the predetermined scanning direction. A method for manufacturing an exposure apparatus, characterized in that the exposure apparatus is tilted with respect to.