JPH0645221A - Projection aligner - Google Patents

Abstract

PURPOSE:To make a focus depth of a longitudinal pattern and that of a transverse pattern nearly the same and to increase the focus depths of both patterns simultaneously, in a modified light source method. CONSTITUTION:A modified light source filter 8 is installed near an emission side face of a fly eye lens 7 of an illumination optical system and a shape of the deformation light source filter 8 is optimized according to an arrangement and a shape of lens elements 7a which constitute the fly eye lens 7. At that time, the number of secondary light sources effective for longitudinal patterns and the number of secondary light sources effective for transverse patterns should be the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus used for forming a fine pattern on a semiconductor integrated circuit, a liquid crystal device or the like.

[0002]

2. Description of the Related Art Recently, a modified light source technique for improving the resolution and depth of focus of a projection optical system has been attracting attention. This is, for example, as disclosed in Japanese Patent Laid-Open No. 4-101148, an exit side focal plane of a fly-eye type integrator (fly-eye lens), or an optical Fourier transform plane for a reticle pattern equivalent to the focal plane. A diaphragm (hereinafter simply referred to as a modified light source filter) that blocks the illumination light near the optical axis of the illumination optical system and limits the light transmission part to only a specific partial area on the surface near the Is.

[0003]

However, in the modified light source technology as described above, the distance and directionality from the optical axis of the illumination optical system of the light transmitting portion have been studied, but the discrete eye formed by the fly-eye lens has been studied. The optimum shape of the shading plate (filter) for a typical secondary light source image has not been studied at all. The fly-eye lens is used to make the illuminance uniform on the reticle surface, and is a lens group in which several tens of single lens elements having the same shape are arranged in a plane perpendicular to the optical axis of the illumination optical system. . Further, the incident side surface of each lens element is conjugated (image formation relationship) with the pattern surface of the reticle, and the illumination light flux from each lens element is superimposed and incident on the pattern surface, and the illuminance is good by averaging them. Uniformity is obtained.

By the way, since it is convenient that the pattern area on the reticle is rectangular according to the shape of the semiconductor integrated circuit to be exposed, the shape of the incident side surface of each lens element of the fly-eye lens, which is conjugate with this, is the shape. Is also rectangular. As a result, the shape of the exit side surface of each lens element also becomes rectangular, and therefore the array pitch of the fly-eye lenses inevitably differs between the short side direction and the long side direction of the rectangle (lens element). For this reason, the discrete secondary light source image formed on the exit surface of the fly-eye lens (generally having a Fourier transform relationship with the pattern surface of the reticle) is also included in each lens of the fly-eye lens. The pitch differs between the long side direction and the short side direction of the element. Therefore, when a conventional modified light source filter (for example, a filter having a cross-shaped light shielding portion) is used for such a discrete secondary light source, the reticle may be formed depending on the shape of the array of the secondary light source (lens element). It is said that two sets of periodic patterns (hereinafter referred to as a vertical pattern and a horizontal pattern) arranged in each of two directions (vertical direction and horizontal direction) which are substantially orthogonal to each other have different focal depths. There was a problem.

The present invention has been made in view of the above problems. It is possible to perform projection exposure with high resolution and a large depth of focus, and to make the depths of focus of the vertical pattern and the horizontal pattern substantially equal. It is an object of the present invention to provide a projection exposure apparatus provided with a diaphragm (deformed light source filter).

[0006]

In order to solve such a problem, according to the present invention, a plurality of light source images (Li) are formed on a Fourier transform surface of a pattern surface of a mask (R) in an illumination optical system or a surface in the vicinity thereof. Each of a fly-eye integrator (7) that two-dimensionally forms an image, and a plurality of local regions (light transmitting portions 8a to 8d) in which the light amount distribution by a plurality of light source images is decentered from the optical axis (AX) of the illumination optical system. Becomes maximum,
In addition, the light source image and the second periodic pattern (1) that contribute to the depth of focus of the first periodic pattern (14V) in each local region.
A diaphragm member (light-shielding portion 8A or 8B) for partially shielding or dimming a plurality of light source images is provided so that the number of light source images contributing to the depth of focus of 4H) is the same.

Further, a fly-eye type integrator (7) for two-dimensionally forming a plurality of light source images (Li) on or near the Fourier transform surface of the pattern surface of the mask (R) in the illumination optical system, and a plurality of fly eye type integrators (7). The light amount distribution by the light source image becomes maximum in each of the plurality of local regions (light transmitting portions 8a to 8d) decentered from the optical axis (AX) of the illumination optical system, and the optical axis of the illumination optical system (in the Fourier transform plane) ( When the orthogonal coordinate system XY whose origin is AX) is defined, the absolute value of the coordinate position on the orthogonal coordinate system XY of the center of gravity of the light amount distribution in each local area should be substantially equal in the X and Y directions. A diaphragm member (light-shielding portion 8C) that partially shields or dims a plurality of light source images is provided.

[0008]

According to the present invention, a plurality of light source images formed on the exit side focal plane of the fly-eye type integrator (fly-eye lens) (optical Fourier transform plane of the pattern surface of the mask) are specified according to their positions. Focusing on the effect of increasing the depth of focus of a mask pattern of a specific pitch and a particular direction, in particular, a light source image that increases both the depth of focus for each of the vertical pattern and the horizontal pattern in the mask pattern is selectively selected. I decided to use it. Therefore, good depth of focus can be obtained for each of the vertical pattern and the horizontal pattern. Specifically, focusing on one light transmitting portion (local area) of the diaphragm member, a light source image that is particularly effective in expanding the depth of focus with respect to either the vertical pattern or the horizontal pattern, and a very effective light source image. The ratio (the ratio of the numbers) of the light source image that is not effective and the ratio of the light source image that is particularly effective and the light source image that is not very effective for the other pattern are made substantially equal. In other words, a light source image effective for expanding the depth of focus in both the vertical pattern and the horizontal pattern, and a light source image effective for expanding the depth of focus only in the vertical pattern or the horizontal pattern are vertically generated. The same number is used for the directional pattern and the lateral pattern. Alternatively, the absolute value of the coordinate position of the center of gravity of the light amount distribution in one light transmitting portion may be substantially equal in the X direction and the Y direction,
A light source image effective for expanding the depth of focus for both the vertical pattern and the horizontal pattern, and at least one light source image other than the light source image effective for both patterns in the light transmitting portion are selected and used. . Therefore, the loss of light amount due to the diaphragm member and the deterioration of the illuminance uniformity on the reticle (or wafer) are minimized, and the depths of focus for the vertical pattern and the horizontal pattern are substantially equal and both are increased. It becomes possible to do.

[0009]

1 shows a schematic structure of a projection exposure apparatus according to an embodiment of the present invention. An illumination light beam 3 emitted from a light source 1 such as a mercury lamp is reflected and focused by an elliptic mirror 2 and a bending mirror 5 is provided. The light beams are made into substantially parallel light beams by the input lens systems 4 and 6 and are incident on the fly-eye lens 7. here,
Each incident side surface of the plurality of lens elements 7a forming the fly-eye lens 7 is substantially conjugate (image forming relationship) with the pattern surface of the reticle R. An image of the light source 1 (secondary light source) is formed on the exit side surface of each lens element 7a, and the exit side surface of the fly-eye lens 7 is optically Fourier-transformed with respect to the pattern surface of the reticle R. Has become. In this embodiment, a modified light source filter (diaphragm member of the present invention) 8 is provided near the exit surface of the fly-eye lens 7. The modified light source filter 8 has four light transmitting portions 8a to 8d (only 8a and 8b are shown here), and the specific shape thereof will be described later. The fly-eye lens 7 may form an image of the light source 1 in a plane separated from the exit surface of each lens element 7a by a predetermined distance in the optical axis AX direction. At this time, the modified light source filter 8 is arranged on the above-mentioned surface (focal plane on the exit side of the fly-eye lens 7). By the way, the modified light source filter 8 is integrally fixed to a holding member (for example, a turret plate, a slider, etc.) 10 together with a filter of another shape, for example, a ring diaphragm, or an aperture diaphragm 9 having a normal shape (circular or rectangular shape). And is arranged in the illumination optical path in a replaceable manner by the drive system 10a.

Now, the modified light source filter 8 (light transmitting portion)
The illumination light flux 13 that has passed through is the condenser lens group 1
1 and the pattern 14 of the reticle R via the mirror 12.
Illuminate. The light transmitted through the pattern 14 and diffracted is focused and imaged by the projection optical system 15 to form an image of the pattern 14 on the wafer 16. The wafer 16 is mounted on a stage 17 which can be two-dimensionally moved by a motor 18. By the way, in FIG. 1, the reticle pattern 1 of the illumination light flux 13
The incident angle θ on the light source 4 is determined according to the shape of the modified light source filter 8 (light transmitting portion, that is, each position of the secondary light source). The main control system 20 illuminates, through the drive system 10a, a filter most suitable (optimal) for the reticle pattern 14 based on the type of reticle, the fineness of the pattern (line width, pitch), the cycle direction, and the like. In addition to placing (setting) in the optical path,
Controls the entire device.

FIG. 2A shows a schematic structure of the reticle R, which is an effective area (pattern area) in the reticle R.
The PA has a rectangular shape according to the shape of the semiconductor integrated circuit. Here, as the reticle pattern 14, a vertical pattern (a periodic pattern arranged in the X direction) 14V and a horizontal pattern (a periodic pattern arranged in the Y direction).
14H.

FIG. 2B shows an example of the shape of the fly-eye lens 7, which is suitable for uniformly illuminating the reticle R shown in FIG. 2A, that is, the rectangular effective area PA, particularly the exit side surface. And each lens element 7a has a rectangular shape substantially similar to the effective area PA. A black circle Li at the center of each element 7a indicates an image (secondary light source) of the light source 1 formed by each element.
Although the incident side surface of the fly-eye lens 7 has the same shape as the exit side surface, the illuminance distribution on the incident side surface is substantially uniform, and the illumination light flux emitted from each element 7a is effective area P.
It is superimposed on A to make the illuminance on the pattern surface uniform. Since the incident side surface of the fly-eye lens 7 and the reticle pattern surface are in an image-forming relationship, when the shape of each lens element 7a is similar to the shape of the effective area PA, the fly-eye lens 7 has a light quantity. The reticle R can be illuminated most efficiently.

In the discrete secondary light source distribution as shown in FIG. 2B, the light source Li near the optical axis AX of the illumination optical system is
It is not a preferable light source in view of the resolution and depth of focus of the projection optical system. On the other hand, for the light source Li far from the optical axis AX,
It is not preferable in terms of depth of focus for a pattern in a specific direction. About this, 1992 SPIE Optical / Laser
Microlithography V Vol.1674-63 "New Imaging Tech
nique for 64M DRAM "and the like. For example, for the vertical pattern 14V in FIG.
The secondary light source (black circle) in the two areas (hatched portions) LV shown in (A) is particularly effective in terms of the depth of focus. On the other hand, for the lateral pattern 14H, the secondary light source (black circle) in the two regions (hatched portions) LH shown in FIG. 6B is particularly effective in terms of the depth of focus. The positions of the regions LV and LH are different depending on the pitch of each pattern.
Further, FIGS. 6A and 6B both show the exit side surface of the fly-eye lens, and the shape and arrangement (the number of elements, etc.) are different from those of the fly-eye lens in FIG. 2B. It is assumed that the directionality (rotation within the plane of the paper) is the same. This also applies to the fly-eye lenses in FIGS. 3, 4, and 5 described later.

Since an actual reticle pattern includes many vertical and horizontal patterns, an area that is convenient both in the vertical and horizontal directions is selected as the secondary light source.
That is, it suffices to select the common area of the areas LV and LH. However, when the secondary light source is selected by the above method, the number of secondary light sources (the number of effective lens elements) is reduced, and thus the illumination light amount is significantly reduced and the illuminance uniformity on the reticle surface is deteriorated. become.

FIG. 3 shows a concrete structure of the modified light source filter 8 according to the first embodiment of the present invention, in which a hatched portion 8A in the drawing is shown.
Indicates a light shielding part. In FIG. 3, all of the secondary light source units (corresponding to the overlapping portions of the regions LV and LH in FIG. 6) effective for both the vertical pattern and the horizontal pattern are used as the light transmitting unit, and the vertical pattern and the horizontal pattern are used. Several secondary light sources (lens elements) that are particularly effective only for one of the directional patterns are also used as the light transmitting portions.

Focusing on one light transmitting portion 8a in FIG. 3, the six secondary light sources within the broken line 7e are effective light sources for both the vertical pattern and the horizontal pattern. Also, 2
The secondary light source 7V has a vertical pattern 14 in terms of the depth of focus.
It is effective only for V, and the two secondary light sources 7H are effective only for the lateral pattern 14H in terms of depth of focus. This means that the other three light transmitting parts 8b, 8c,
The same applies to 8d.

Therefore, regarding the vertical pattern, the effective secondary light source on the depth of focus is (6 + 2) × 4 = 32
The number of secondary light sources (7H) that are not so effective is 2 × 4 = 8. On the other hand, looking at the horizontal pattern,
The effective secondary light source on the depth of focus is (6 + 2) × 4 = 32
The number of secondary light sources (7 V) that are not so effective is 2 × 4 = 8. That is, the ratio of the number of effective secondary light sources to the number of ineffective secondary light sources in the depth of focus is equal in the vertical pattern and the horizontal pattern. From the above, by using the modified light source filter as shown in FIG. 3, while preventing the loss of the illumination light amount and the deterioration of the illuminance uniformity, the depths of focus of the vertical pattern and the horizontal pattern are substantially equal, and It is possible to realize a deformed light source that is sufficiently large.

In the modified light source filter according to this embodiment, simply, the number of secondary light sources effective for only one of the vertical pattern and the horizontal pattern may be the same for both. At this time, for example, the secondary light sources that are effective only for the vertical pattern (in other words, the secondary light sources that are not so effective for the horizontal pattern) have the same number (4 in this embodiment) in the left-right direction on the paper surface with respect to the optical axis AX. It is good to set each one. This also applies to the horizontal pattern.

The modified light source filter (light-shielding portion 8A) shown in FIG. 3 is designed to follow the arrangement (shape) of the lens elements 7a of the fly-eye lens 7. In other words, the boundary portion (edge portion) between the light-shielding portion 8A and the light-transmitting portion is substantially along the boundary line between the elements. That is, the edge portion of the modified light source filter (light shielding portion) does not coincide with each of the discrete secondary light sources. This is for avoiding a change in the illumination characteristic (a change in the illumination light amount, etc.) due to the positional displacement of the filter in the device provided with the filter exchange mechanism shown in FIG. For this reason, in this embodiment (FIG. 3), both the vertical and horizontal widths of the light shielding portion 8A are approximately twice the width of the lens element 7a. Here, 2 in each of the vertical and horizontal directions.
Since the next light source (lens element) is shielded from light, the light-shielding width is set to be twice, but in general, it may be n times (n is an integer) the width of the lens element to be shielded.

By the way, in the reticle (actual reticle) actually used in the projection exposure apparatus, both the X-direction pattern and the Y-direction pattern do not consist only of patterns having a specific pitch, but a pattern having a coarse pitch to some extent. , Or a pattern with a fine pitch is mixed. For such an actual reticle, it is difficult to precisely define the shapes of secondary light sources (the number and position of light source images) that are suitable for the horizontal pattern and the vertical pattern, respectively, as described above. This is because in an actual reticle, the optimum shape of the secondary light source differs for each of a plurality of patterns having different pitches.

Therefore, in the above-described embodiment, the method of making the number of secondary light sources effective for each of the vertical pattern and the horizontal pattern (equal to the same number) has been described.
As an example, a method will be described in which the contribution to the effect of increasing the depth of focus for each of the X-direction pattern and the Y-direction pattern on the actual reticle is made equal on average for all secondary light sources. In the present embodiment as well, description will be made on the premise of the modified light source filter (light-shielding portion 8A) shown in FIG.

In this embodiment, an orthogonal coordinate system XY having the optical axis AX as a coordinate origin is defined in FIG. 3, and only the lens element in the light transmitting portion 8a among all the lens elements in FIG. 3 is defined. Pay attention. The size of each lens element is 6 in the horizontal (X) direction and 8 in the vertical (Y) direction (however, the unit is arbitrary). At this time, the coordinate position of each of the 10 secondary light sources on the orthogonal coordinate system XY is a combination of X = 9, 15, 21, 27, 33 Y = 12, 20, 28. For example, the coordinate positions of the two secondary light sources 7H are represented as (9, 20) and (33, 12).

Therefore, when the centroids of the 10 secondary light sources (light quantity distribution) in the light transmitting portion 8a are obtained, the coordinate position is (2
0.4, 18.4). That is, the ten secondary light sources as a whole (as the light amount center of gravity) have the X direction pattern and the Y direction.
The depth of focus can be increased almost evenly for each of the directional patterns. Here, the light transmitting portion 8a
Only the three light transmitting portions 8b,
The same applies to 8c and 8d.

As described above, in the present embodiment, the difference between the X coordinate (absolute value) and the Y coordinate (absolute value) of the light amount centroid of each light transmitting portion is zero, or the X coordinate (or Y) as in the above example. The absolute value of (coordinates) may be within about 10%. As a result, even in this embodiment, while preventing the loss of the illumination light amount and the deterioration of the illuminance uniformity,
It is possible to increase the depth of focus almost evenly for each of the X-direction pattern and the Y-direction pattern. Since the modified light source filter of the first embodiment shown in FIG. 3 is used here as it is, the effective number of secondary light sources for each of the vertical pattern and the horizontal pattern is the same. However, in the present embodiment, the number of effective secondary light sources for the vertical pattern and the horizontal pattern does not have to be the same, and the point is that the difference is zero or less than about 10%.

By the way, when the vertical pattern and the horizontal pattern on the reticle are further miniaturized, the area effective for increasing the depth of focus in the secondary light source (the position of the center of gravity of the light quantity distribution of the light transmitting portion) is shown in FIG. ) And (B) are shifted to the outside (direction away from the optical axis AX) of the regions LV and LH. In such a case, a modified light source filter (8C) as shown in FIG. 5 is used, and a secondary light source outside the filter (8A) of FIG. 3 is transmitted. On the other hand, when the pitch of the vertical and horizontal patterns becomes coarse, the modified light source filter (8
B) is used so that the secondary light source more inside than the filter (8A) in FIG. 3 is transmitted.

Here, the modified light source filter 8 shown in FIG.
Similar to the first embodiment, B has the same number of effective secondary light sources for the vertical pattern and the horizontal pattern. Focusing on the upper right part of FIG. 4 (corresponding to the light transmitting part), the secondary light sources effective for the vertical pattern are six in the broken line 7e and the secondary light source 7.
There are a total of eight Vs, and there are six secondary light sources effective in the horizontal pattern, which are within the broken line 7e and eight secondary light sources 7H.
When the center of gravity of the light quantity at this time is calculated, the coordinate position is (1
8.0, 18.4).

The modified light source filter 8C shown in FIG.
Is an example of the filter according to the second embodiment. Focusing on the upper right part of FIG. 5, there are 6 secondary light sources effective in the vertical pattern in the broken line 7e and 8 secondary light sources 7V in total,
The secondary light sources that are effective for the horizontal pattern are 6 in the broken line 7e,
And a total of seven secondary light sources 7H. That is, the number of effective secondary light sources for the vertical pattern and the horizontal pattern is not the same. Further, in FIG. 5, there is only one secondary light source 7G that is not very effective in both the vertical pattern and the horizontal pattern. However, when the center of gravity of the light quantity in the upper right part of FIG. 5 is obtained, its coordinate position is (20.4, 1
9.2). That is, the difference between the absolute values of the X coordinate and the Y coordinate is within about 10% of the X coordinate (or the Y coordinate), and the light amount center of gravity has almost the same value in the X direction and the Y direction. Therefore, even with an actual reticle in which patterns of various pitches are mixed, practically evenly uniform patterns can be obtained for each of the X-direction pattern and the Y-direction pattern while minimizing the loss of light amount and the deterioration of illuminance uniformity. It is possible to increase the depth of focus.

In the above first and second embodiments, focusing on one light transmitting portion of the modified light source filter, the secondary light source effective for both the X-direction pattern and the Y-direction pattern (broken lines in FIGS. 3 to 5). 6 in 7e) and at least one 2
By selecting and using the secondary light source, it is possible to minimize the loss of light amount and the deterioration of illuminance uniformity. Particularly, in the first embodiment, the secondary light sources are selected so that the number of secondary light sources effective only in the X direction pattern and the number of secondary light sources effective only in the Y direction are the same. On the other hand, in the second embodiment, the number of effective secondary light sources for the X-direction pattern and the Y-direction pattern does not have to be the same, and a secondary light source that is not so effective for both the X-direction pattern and the Y-direction pattern is selected. You may. That is, the secondary light source is selected so that the X-coordinate (absolute value) and the Y-coordinate (absolute value) of the center of gravity of the light amount are substantially equal. Therefore, it is possible to realize a modified light source in which the depths of focus of the X-direction pattern and the Y-direction pattern are substantially equal to each other and are sufficiently increased. Further, there is no difference in line width between the transferred images of the X-direction pattern and the Y-direction pattern.

By the way, although the modified light source filter 8 is arranged on the exit side focal plane of the fly-eye lens 7 in each of the above embodiments, other than that, for example, in the vicinity of its conjugate plane (optical Fourier transform plane of the reticle pattern). You may arrange.
Further, the modified light source filter may be arranged in the vicinity of the incident surface of the fly-eye lens 7 (a surface which is substantially conjugate with the reticle pattern). In addition, the light shielding part of the modified light source filter (8A
Etc.) may be used as the dimming unit. The modified light source filter may be a variable diaphragm using a liquid crystal display element or an electrochromic element.

Further, in the apparatus of FIG. 1, only one set of fly-eye lens is arranged, but, for example, Japanese Patent Laid-Open No. 63-665.
As disclosed in Japanese Patent No. 53, two sets of fly-eye lenses may be arranged in series. In this case, the modified light source filter according to the present invention may be arranged on either the incident side surface or the exit side surface of the first-stage (light source side) fly-eye lens or the second-stage (reticle side) fly-eye lens. . When the modified light source filter is arranged near the exit side of the second-stage fly-eye lens, a plurality of lenses are formed on the exit side of each lens element (corresponding to the number of lens elements of the first-stage fly-eye lens). The third light source of (3) is shielded (or dimmed) in element units in exactly the same manner as in the previous embodiment.

Furthermore, in each of the above embodiments, the light shielding portion (outer shape diaphragm) that defines the outer shape of the fly-eye lens is not shown, but the light shielding portion may be provided for shielding stray light or the like. At this time, the light shielding portion may be formed so that its edge portion follows the arrangement of the lens elements. Further, some of the secondary light sources may be shielded by this light shielding portion. The exposure light source 1 of the projection exposure apparatus shown in FIG. 1 may use, for example, a harmonic wave of an excimer laser, a metal vapor laser, a YAG laser, an X-ray, or the like, instead of the mercury lamp.

[0032]

As described above, according to the present invention, the shape of the modified light source filter is optimized according to the arrangement of the lens elements of the fly-eye type integrator, so that the loss of the illumination light amount and the deterioration of the illuminance uniformity can be prevented. While suppressing, the depth of focus of both the vertical pattern and the horizontal pattern is almost equal,
And it is possible to increase together.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration of a reticle and a fly-eye lens in FIG.

FIG. 3 is a diagram showing a specific configuration of a modified light source filter according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a modified example of the modified light source filter shown in FIG.

FIG. 5 is a diagram showing a specific configuration of a modified light source filter according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a secondary light source effective for each of a vertical pattern and a horizontal pattern.

[Explanation of symbols]

 7 Fly-eye lens 8 Deformed light source filter 8A-8C Light-shielding part

Claims (5)

[Claims] 1. Illumination for illuminating illumination light from a light source on a mask having a first periodic pattern and a second periodic pattern arranged in directions orthogonal to each other and shaping the illumination light into a substantially uniform intensity distribution. In a projection exposure apparatus including an optical system and a projection optical system for image-projecting an image of the pattern of the mask on a photosensitive substrate, a Fourier transform surface for the pattern surface of the mask in the illumination optical system, or a vicinity thereof. A fly-eye type integrator that forms a plurality of light source images on a surface; and a light amount distribution due to the plurality of light source images becomes maximum in each of a plurality of local regions decentered from the optical axis of the illumination optical system, and within the local region The light source images contributing to the depth of focus of the first periodic pattern and the light source images contributing to the depth of focus of the second periodic pattern have the same number of partial light source images. Shading, or a projection exposure apparatus characterized by comprising a stop member for dimming. 2. The aperture member has a ratio of the number of light source images contributing to the depth of focus of the first periodic pattern to the number of light source images not contributing to the depth of focus, and the depth of focus of the second periodic pattern. 2. The plurality of light source images are partially shielded or dimmed so that the ratio of the number of light source images contributing to the light source image to the ratio of the number of light source images not contributing to the light source is substantially equal. The projection exposure apparatus described. 3. Illumination for illuminating illumination light from a light source on a mask having a first periodic pattern and a second periodic pattern arranged in directions orthogonal to each other by shaping the illumination light into a substantially uniform intensity distribution. In a projection exposure apparatus including an optical system and a projection optical system for image-projecting an image of the pattern of the mask on a photosensitive substrate, a Fourier transform surface for the pattern surface of the mask in the illumination optical system, or a vicinity thereof. A fly-eye type integrator that forms a plurality of light source images on a surface; a light amount distribution by the plurality of light source images has a maximum in each of a plurality of local regions decentered from the optical axis of the illumination optical system, and in the Fourier transform plane When the orthogonal coordinate system XY with the optical axis of the illumination optical system as the coordinate origin is defined in, the absolute position of the coordinate position on the orthogonal coordinate system XY of the center of gravity of the light amount distribution in the local area is defined. So they approximately equal in the X and Y directions, the plurality of light source images partially shielded, or a projection exposure apparatus characterized by comprising a stop member for dimming. 4. The diaphragm member has four light transmission parts whose center of gravity of the light amount distribution in the local region is substantially equidistant from the optical axis of the illumination optical system, and the transmission parts are the fly-eye type. 4. The projection exposure apparatus according to claim 1, wherein the shape is determined according to the arrangement of a plurality of optical elements that form the integrator. 5. The projection exposure apparatus according to claim 4, wherein the diaphragm member is arranged in the vicinity of the incident side surface of the fly-eye type integrator, the exit side focal plane, or a conjugate surface thereof.