JP3335139B2 - Exposure method, exposure apparatus, and device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exposure method, an exposure apparatus, and a device manufacturing method, and more particularly, to an exposure method and an exposure apparatus for performing multiple exposure of a fine circuit pattern on a photosensitive substrate. The exposure method and the exposure apparatus according to the present invention include various devices such as a semiconductor chip such as an IC / LSI, a display device such as a liquid crystal panel, a detection device such as a magnetic head, an imaging device such as a CCD, and a wide area pattern used in micromechanics. Used for manufacturing.

[0002]

2. Description of the Related Art Conventionally, an X-ray proximity exposure apparatus having a configuration shown in FIG. 19 is known (for example, Japanese Patent Application Laid-Open No. 2-100131). In the figure, 1 is S
An X-ray source (light emitting point) such as OR, 2 is a SORX ray that has spread in a slit shape in the x direction, 3 is a convex mirror (for example, made of SiC) for expanding the slit X-ray 2 in the y direction, 2a
Is an X-ray enlarged in a plane by the convex mirror 3, 7 is an object to be exposed such as a semiconductor wafer coated with a resist, and 10 is a mask. Reference numeral 4 denotes a beryllium thin film for separating the atmosphere on the SOR side from the atmosphere on the mask and the object to be exposed, and 5 denotes a focal plane type shutter for adjusting the exposure amount. Exposure is performed by disposing the mask 10 and the object 7 at an interval (gap) of about 10 μm, opening the shutter 5, and making the slit-shaped high-brightness X-rays 2 from SOR or the like planar by the convex mirror 3. The magnified X-rays 2a are irradiated onto the exposure target 7 via the mask 10, and the pattern image of the mask 10 is transferred onto the exposure target substrate 7 at the same magnification.

However, in the above-described conventional X-ray proximity exposure apparatus, X-rays have a wavelength of 0.5 nm or more.
Those having a thickness of about 20 nm are used. Therefore, considering only the wavelength, a high resolution of 0.05 μm (50 nm) or less should be obtained. However, at present, it is difficult to manufacture such a high-resolution mask. For example, when a mask having a nominal minimum line width of 0.05 μm is manufactured by a conventional technology for manufacturing a mask having a minimum line width of 0.1 μm (100 nm), the line and space of the completed pattern (line width and spacing; , L & S) and errors in position and the like are directly transferred as mask defects, resulting in a problem that a pattern to be formed is lost or a position shift occurs. In addition, there is also a problem that a sufficient contrast cannot be obtained and a resolution cannot be obtained because an actual mask pattern is not produced with a sufficient line width or interval or a desired accuracy.

[0004] For this reason, recently, the exposure method and the exposure apparatus for performing double exposure of periodic pattern exposure and normal exposure on a substrate to be exposed (photosensitive substrate) have been proposed.
It has been studied to create a circuit pattern having a portion of 15 μm or less. The `` normal exposure '' here has lower resolution than the periodic pattern exposure, but is exposure that can be exposed in an arbitrary pattern.
Projection exposure capable of projecting a mask pattern by a projection optical system is used. The pattern exposed by the normal exposure includes a fine pattern having a resolution equal to or less than the resolution (hereinafter, referred to as a normal exposure pattern), and the periodic pattern exposure forms a periodic pattern having the same line width as the fine pattern. For this periodic pattern exposure, a Levenson-type phase shift mask or the like is used. Part 1
An example is shown in FIG. By exposing the periodic pattern of FIG. 1 and the normal exposure pattern of FIG. 1 at the same position, it becomes possible to obtain a fine pattern FIG. As described above, the pattern to be finally created is exposed as a normal exposure pattern.Since the normal exposure pattern includes a pattern having a resolution lower than that of the normal exposure pattern, the pattern is exposed by exposing a high-resolution periodic pattern to the same position. Normally, the resolution of the exposure pattern can be improved, and finally a desired pattern including fine lines having a resolution lower than the resolution can be formed.

[0005]

In the above-mentioned double exposure, the high-resolution periodic pattern shown in FIG. 1 is exposed at the same position in order to improve the resolution of the normal exposure pattern shown in FIG. In this double exposure, if the fine line portion of the pattern shown in FIG. 1 coincides with the periodic direction in the drawing, no particular problem occurs. However, as a normal exposure pattern, when an example the case of a pattern of direction are mixed in the fine line as shown in FIG. 2, the periodic pattern
Direction of fine lines perpendicular to the periodic direction can resolve without problems, but the same direction of the fine line between the periodic direction may not be able to resolve. A case where a positive resist is used will be described with reference to FIGS. 1 and 2 by taking patterns called a gate pattern and a T gate pattern as examples. In the drawing, it is assumed that light is transmitted through all the periodic patterns and the phases are inverted. This periodic pattern has a cycle number of 2
The above is assumed. In addition, the normal pattern has a constant binary amplitude in which light is transmitted to the periphery and the pattern portion is shielded from light.

In the case of the pattern as shown in FIG. 1, the direction of the fine lines of the gate pattern which is the normal exposure pattern in FIG. 1 matches the direction of the pattern constituting the periodic pattern in FIG. Therefore, it is possible to improve the resolution of the fine line of the gate pattern which is the normal exposure pattern in FIG. Next, in the case of the T gate pattern shown in FIG. 2 having fine lines orthogonal to the fine lines, the directions of the fine lines are mixed. As described above, when a pattern in which the directions of fine lines are mixed is created, if a periodic pattern as shown in the figure is used, fine lines perpendicular to the periodic direction are resolved, but the periodic
Fine lines in the same direction cannot be resolved. Therefore,
In the case where the direction of the period is mixed, if the pattern interval A becomes smaller than the resolution, the pattern interval A in FIG. 2 cannot be separated by using only the simple periodic pattern conventionally used. As described above, when performing the double exposure of the periodic pattern and the normal exposure pattern, if the shape of the normal pattern is complicated, a good image may not be obtained with a simple high-resolution periodic pattern conventionally used. In particular, it is difficult to cope with a pattern in which the directions of fine lines are mixed by a conventional method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is intended to correct a pattern distortion due to an optical proximity effect on a pattern having a periodic structure when performing multiple exposure of a pattern having a periodic structure and a normal exposure pattern. It is an object of the present invention to provide an exposure method, an exposure apparatus, and a device manufacturing method capable of obtaining a good pattern by devising such a method.

[0008]

According to the present invention, in order to achieve the above object, an exposure method, an exposure apparatus, and a device manufacturing method are configured as follows. That is, the exposure method according to the present invention is an exposure method for performing multiple exposure including exposure using a first pattern and exposure using a second pattern on a substrate to be exposed. a pattern having a periodic structure for the for correcting the pattern distortion due to the optical proximity effect in the exposure of the second pattern to the pattern of the first (for resolving fine lines) circumference
It is characterized by forming a region without a periodic structure . In the exposure method according to the present invention, the second pattern is characterized in that the light intensity distribution on the wafer surface is multi-valued. Further, the exposure method according to the present invention is characterized in that the second pattern is a design pattern itself or a design pattern itself. Further, the exposure method of the present invention is characterized in that the first pattern is subjected to pattern distortion correction by the optical proximity effect such that the light intensity distribution approaches the shape of the design pattern. Further, in the exposure method of the present invention, in the first pattern and the second pattern, the correction of the pattern distortion due to the optical proximity effect is performed so that the light intensity distribution of a composite image obtained by exposing the first pattern and the second pattern is close to a design pattern. It is characterized by performing. Further, in the exposure method of the present invention, a region where the line width is partially increased is formed in a region of the first pattern where the periodic structure does not exist, and the pattern distortion due to the optical proximity effect is corrected. It is characterized by performing. The exposure method of the present invention, in the above without periodic structure region of the first pattern, the region overlapping with the direction of fine lines not perpendicular to the direction of the period of the first pattern of the second pattern An isolated line is formed, and the line width of the isolated line is made larger than the line width of the fine line of the second pattern. In the exposure method according to the present invention, the isolated line has the same line width as a fine line of a composite image created from a periodic portion in the first pattern and a fine line of a composite image created from the isolated line. Thus, the feature is to optimize the line width of the isolated line. The exposure method of the present invention, it of the periodic structure of the first pattern
In this case , a correction pattern is formed in a region where the pattern distortion is corrected by the optical proximity effect. The exposure method of the present invention, the correction pattern, the region without the periodic structure of the first pattern, the same as the direction of the period of the periodic structure of the first pattern of the second pattern An isolated line formed so as to overlap a fine line in a direction is formed to have a predetermined shape in consideration of shortening of the isolated line. Further, the exposure method of the present invention is characterized in that, in the first pattern, a light shielding portion is provided for a pattern having a line width three times or more as large as the fine line of the second pattern, and the light amount is adjusted. Also,
The exposure method of the present invention is characterized in that the first pattern adjusts the light amount balance of the entire first pattern by adjusting the line width of the pattern. Further, the exposure method of the present invention is characterized in that, when an intersecting pattern is used in the first pattern, a light-shielding portion is provided at or near the intersection. Further, the exposure method of the present invention is characterized in that when a pattern orthogonal to an L-shape is used in the first pattern, a light-shielding portion is provided at or near the intersection.
Further, the exposure method of the present invention is characterized in that, when a pattern orthogonal to a T-shape is used in the first pattern, a light-shielding portion is provided at an intersection or in the vicinity thereof. Further, the exposure method of the present invention is characterized in that the first pattern is a periodic pattern having a cycle number of 2 or more, and is configured by one of a Levenson type phase shift mask and a binary type mask. I have.

An exposure apparatus according to the present invention is an exposure apparatus having an exposure mode in which a substrate to be exposed is subjected to multiple exposure including exposure using a first pattern and exposure using a second pattern. Is a pattern having a periodic structure for resolving fine lines, wherein the first pattern has a periodic structure for correcting pattern distortion due to an optical proximity effect in exposure of the second pattern .
It is characterized by having no area . Also, the exposure apparatus of the present invention, the second pattern is characterized in that the light intensity distribution on the wafer surface is multi-valued. Further, the exposure apparatus of the present invention is characterized in that the second pattern is a design pattern itself or a design pattern itself. Further, the exposure apparatus of the present invention is characterized in that the first pattern is configured to correct the pattern distortion due to the optical proximity effect such that the light intensity distribution is close to the shape of the design pattern. And Further, the exposure apparatus of the present invention corrects pattern distortion due to the optical proximity effect in the first pattern and the second pattern such that the light intensity distribution of a composite image obtained by exposing the first pattern and the second pattern is close to a design pattern. Characterized in that it is configured to perform Further, the exposure apparatus of the present invention includes a configuration in which a region having a line width that is partially large is provided in a region of the first pattern that does not have the periodic structure , and a pattern distortion is corrected by an optical proximity effect. It is characterized by having. The exposure apparatus of the present invention, the first pattern
In the region without the periodic structure , the second pattern has an isolated line in a region overlapping a fine line in a direction not orthogonal to a direction of a period of the periodic structure of the first pattern,
The line width of the isolated line is formed to be larger than the line width of the fine line of the second pattern. In the exposure apparatus of the present invention, the isolated line has the same line width as a fine line of a composite image created from a periodic portion in the first pattern and a fine line of a composite image created from the isolated line. Thus, the feature is that the line width of the isolated line is optimized. Further, the exposure apparatus according to the present invention is characterized in that a correction pattern is provided in an area of the first pattern having no periodic structure , and the pattern distortion is corrected by the optical proximity effect. The exposure apparatus of the present invention, the correction pattern, the said circumferential <br/> life without structural region of the first pattern, said one of said second pattern
In an isolated line formed so as to overlap a fine line in the same direction as the direction of the period of the periodic structure of the pattern, the pattern is formed to have a predetermined shape in anticipation of shortening of the isolated line. I have. Further, the exposure apparatus of the present invention is characterized in that a light-shielding portion is provided for a pattern having a line width three times or more as large as a fine line of the second pattern in the first pattern, so that the light amount is adjusted. . Also,
The exposure apparatus of the present invention is characterized in that the first pattern adjusts the light amount balance of the entire first pattern by adjusting the line width of the pattern. Further, the exposure apparatus of the present invention is characterized in that when there is an intersecting pattern in the first pattern, a light-shielding portion is provided at the intersection or near the intersection. Also,
The exposure apparatus according to the present invention is characterized in that, in the first pattern, L
When there is a pattern orthogonal to the character shape, a light-shielding portion is provided at or near the intersection. Further, the exposure apparatus of the present invention is characterized in that, when there is a pattern orthogonal to the T-shape in the first pattern, a light-shielding portion is provided at the intersection or in the vicinity thereof. Further, the exposure apparatus of the present invention includes the first
Is a periodic pattern having two or more periods,
It is characterized in that it is constituted by either a Levenson type phase shift mask or a binary type mask. Further, a device manufacturing apparatus of the present invention is characterized in that a device is manufactured by using any one of the above-described exposure methods or exposure apparatuses of the present invention.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, in the case of performing multiple exposure using a periodic pattern and a normal exposure pattern, the present invention provides a fine pattern by adding a device in which a period is partially broken to a simple periodic pattern. Even when creating a complicated pattern such as a pattern in which the directions of the lines are mixed, it is possible to reproduce all the fine lines satisfactorily. Here, by adding a contrivance to the periodic pattern, the periodic pattern is actually composed of a part having a periodic structure and a part without the periodic structure. For convenience, this is also referred to as a periodic pattern. Further, by devising such a periodic pattern, it is possible to eliminate pattern distortion caused by the optical proximity effect, which is generated particularly when a fine pattern having a resolution or less is formed. When performing multiple exposure, for example, double exposure is intended to improve the resolution by exposing two patterns at the same position, so that the periodic patterns used here all conform to the shape of the normal exposure pattern. Designed.

As will be described more specifically in the embodiments, the above-described contrivance on the periodic pattern is applied particularly as follows. The pattern distortion due to the optical proximity effect is corrected by changing the line width of the periodic pattern with respect to the normal exposure pattern. The pattern distortion due to the optical proximity effect is corrected by changing the shape of the periodic pattern with respect to the normal exposure pattern. A light-shielding portion is provided for a pattern in which the line width of the periodic pattern is at least three times as large as the fine line, and the light amount is adjusted. -When the periodic pattern intersects the L-shape, light is provided near the L-shape intersection in order to prevent the intensity concentration at the intersection. -When the periodic pattern intersects the T-shape, a light shield is provided near the T-shape intersection in order to prevent the intensity concentration at the intersection. By using the periodic pattern that has been devised as described above, it is possible to correct pattern distortion due to the optical proximity effect even in a pattern in which the directions of fine lines are mixed, and to obtain a good composite image. .

[0012]

FIG. 3 is a flowchart showing the double exposure method. Although the flow of each block of periodic pattern exposure, normal exposure, and development is shown, the order of periodic pattern exposure and normal exposure may be as shown in FIG. 5 or vice versa, and when a plurality of exposure steps are included. Alternatively, of course, it is also possible to carry out alternately. Further, a step of performing precise alignment is performed on each exposure step side, but details regarding this processing are omitted. In this embodiment, Kr having a wavelength of 248 nm is used.
The present invention relates to a device for a periodic pattern when performing double exposure of a periodic pattern exposure and a normal exposure using an F excimer stepper.

Next, the principle of double exposure will be described. In the double exposure, the normal exposure and the periodic pattern exposure are performed without a developing step. In this method, a periodic pattern is exposed at an exposure threshold value or less of a resist, and thereafter, a normal exposure having an exposure amount having a multi-value distribution is performed. The exposure amount of the normal exposure has a different exposure amount distribution for each small region of the exposure pattern region (exposure region), and each exposure amount may be equal to or greater than or equal to an exposure threshold. All the exposure amounts mentioned here indicate the exposure amounts on the resist.

FIG. 21 (2) or (3) shows a circuit pattern (lithography pattern) obtained by exposure.
A description will be given by taking the so-called gate pattern shown in FIG. In the illustrated gate pattern, the minimum line width in the horizontal direction is 0.1 μm, whereas in the vertical direction, the line width is 0.2 μm or more which is within the range of the resolving power by the normal exposure of the apparatus. According to the double exposure method, for such a two-dimensional pattern having a minimum line width pattern requiring high resolution only in the one-dimensional direction only in the horizontal direction, periodic pattern exposure by, for example, two-beam interference exposure is performed. Perform only in the one-dimensional direction that requires high resolution.

FIG. 20 shows an exposure amount distribution at each exposure stage. Numerical values shown in the diagram of FIG. 20 represent exposure amounts on the resist. In FIG. 20, FIG.
0 (1) is an exposure amount distribution by a periodic exposure pattern in which a repetitive pattern occurs only in one-dimensional direction. The exposure amount other than the pattern is zero, and the pattern part is 1. FIG. 20B shows an exposure amount distribution by multi-valued normal exposure. The exposure amount other than the pattern is zero, and the pattern portion has a distribution of 1 and 2, here a binary value.
If these exposures are performed by double exposure without going through the development process, a distribution of the sum of the respective exposure amounts is generated on the resist, and the exposure amount distribution is as shown in FIG. here,
When the exposure threshold of the resist is between 1 and 2, 1
A larger portion is exposed, and a pattern as shown by a thick line in FIG. 20 (3) is formed by development.

That is, the exposure pattern by the periodic pattern exposure, which is outside the area surrounded by the thick line, is equal to or less than the exposure threshold value of the resist and disappears by development. With respect to the portion where the exposure amount equal to or less than the exposure threshold value of the resist is distributed in the normal exposure, the portion where the sum of the respective exposure patterns of the normal exposure and the periodic pattern exposure is equal to or greater than the exposure threshold value of the resist is formed by development. You. Accordingly, an exposure pattern having the same resolution as the exposure pattern of the periodic pattern exposure, which overlaps the respective exposure patterns of the normal exposure and the periodic pattern exposure, is formed. In the exposure pattern area in which the exposure amount equal to or larger than the exposure threshold value of the resist is distributed in the normal exposure, an exposure pattern having the same resolution as the exposure pattern in the normal exposure is formed by overlapping the exposure patterns in the normal exposure and the periodic pattern exposure. Is done.

FIG. 21 shows a pattern and a mask for forming the exposure dose distribution shown in FIG. FIG.
Reference numeral 1 (1) denotes a pattern and a mask in which a repetitive pattern is generated only in a one-dimensional direction that requires high resolution, and can be realized by, for example, a Levenson-type phase shift mask. In the case of the Levenson-type phase shift mask, the white portion and the gray portion in the figure have phases inverted from each other, and a high-contrast periodic exposure pattern is formed by two-beam interference exposure due to the phase inversion effect. The mask is not limited to the Levenson-type phase shift mask, and may be any mask as long as it forms such an exposure distribution.
The period of this exposure pattern is 0.2 μm, and the line width of each line of this exposure pattern is 0.1 μm.
20 by the line and space pattern of FIG.
The exposure distribution shown in (1) is formed.

As a pattern and a mask for forming a multi-value pattern, a mask on which a pattern similar to a circuit pattern to be finally formed is drawn is used. In this case, a mask on which the gate pattern shown in FIG. 21B is drawn is used. As described above, the portion composed of the fine lines of the gate pattern is a pattern having a resolution lower than that of a normal exposure. Therefore, on the resist, the two line portions of the fine lines are not resolved, and have a uniform distribution with low intensity. On the other hand, the pattern at both ends of the fine line is resolved as a pattern having a high intensity because the line width is within the range of the resolving power by the normal exposure of the apparatus. Therefore, when the pattern and the mask shown in FIG. 21B are exposed, the multi-valued exposure amount distribution shown in FIG. 20B is formed.

In this example, the pattern to be formed has a light transmission type light exposure distribution. However, a light shielding type pattern can be formed by using a mask as shown in FIG. The light-shielding type pattern can be realized by using a mask that transmits light to portions other than the pattern and shields light from the pattern portion. In the case of a light-shielding pattern, a pattern with a resolution higher than the resolution blocks light, and the exposure amount distribution becomes zero, whereas a fine pattern with a resolution lower than the resolution is
Since light is not completely shielded and an exposure amount that is half of the exposure amount distribution around the pattern is distributed, a multivalued exposure amount distribution is formed.

From the above, the principle of double exposure is briefly summarized as follows. The exposure pattern by the periodic pattern exposure, in which the maximum exposure amount in the area where the normal exposure is not performed is equal to or less than the exposure threshold value of the resist, disappears by development. 2. An exposure pattern area (exposure area) for normal exposure in which an exposure amount equal to or less than the exposure threshold of the resist is supplied to the resist.
As for the exposure pattern, an exposure pattern having the same resolution as the exposure pattern of the periodic pattern exposure determined by the combination of each exposure pattern of the normal exposure and the periodic pattern exposure is formed. 3. An exposure pattern area (exposure area) for normal exposure in which an exposure amount equal to or more than the exposure threshold of the resist is supplied to the resist.
As for the exposure pattern, an exposure pattern having the same resolution as the exposure pattern of the normal exposure determined by the combination of each exposure pattern of the normal exposure and the periodic pattern exposure is formed.

An advantage of the double exposure method is that if the periodic pattern exposure requiring the highest resolution is performed by two-beam interference exposure using a phase shift mask or the like, the periodic pattern exposure can be performed as compared with the normal pattern exposure by projection exposure. Thus, a much larger depth of focus can be obtained. In the above description, the order of the periodic pattern exposure and the normal exposure is the order of the periodic pattern exposure, but may be reversed or simultaneous.

Embodiment 1 In Embodiment 1, a case where the pattern distortion due to the optical proximity effect is corrected by changing the line width of the periodic pattern with respect to the normal exposure pattern will be described with reference to FIGS. 4 and 5. Will be explained. Here, a case in which a pattern is created by the light shielding portion in FIG. 4A will be described as an example. FIG. 5 shows a procedure for creating a periodic pattern according to a normal exposure pattern. FIG. 4A shows an actually used periodic pattern and a normal exposure pattern. By combining these two patterns, a pattern having the same shape as the normal exposure pattern of FIG. The goal is to obtain

The normal exposure pattern shown in FIG.
There are four vertical fine lines and two horizontal fine lines. In addition, a region where resolution is particularly difficult is a portion where patterns are in contact with each other at an interval equal to or less than the resolution as shown in the figure. Therefore, in the periodic direction, there are many fine lines,
The vertical direction in which resolution is difficult is defined as an area where resolution is difficult . In this way, focusing on the “regions where resolution is difficult” in which the fine lines and the patterns contact each other at intervals smaller than the resolution, and determining the arrangement of the periodic patterns so that they can be resolved, the periodic pattern 1 is shown. It is essential to arrange a periodic pattern in the area. At this time, the length of the periodic pattern is longer than the length of the fine line of the normal exposure pattern. Next, a region where a fine line in the same direction as the periodic direction of the periodic pattern exists is made a large pattern, and the periodic pattern is not arranged. Because if you place a periodic pattern here,
This is because constriction occurs in a fine line in the same direction as the direction. Then, the phase is set as shown in the periodic pattern 2 so that the phases of adjacent patterns including this large pattern are opposite in phase to 0 · π.

Further, the periodic pattern area overlapping with the fine line in the same direction as the periodic direction is shielded by Cr so that no light is transmitted,
Make it a shaded isolated line. The periodic pattern 3 created in this manner is a periodic pattern to be finally used. In this case, since the pattern is formed of a light shielding portion, the periodic direction
In order to resolve a fine line in the same direction as the above, a light shielding portion which is this isolated line is provided. Here, the isolated line needs to be thicker than the line width of the fine line to be actually created. This is because good fine lines cannot be created, for example, the fine lines are thinned or broken due to light wraparound.
Therefore, in order to prevent light from wrapping around the fine line, the line width of the fine line of the pattern to be actually created is 1 L.
In the case of (1), it is necessary to use a slightly thicker periodic pattern of 1.5 L to 3 L. As described above, by using the periodic pattern in which the isolated line is thickened, the line width of the portion having the periodic structure and the line width of the isolated line after double exposure become equal. The line width of the isolated line changes depending on the line width of a fine line to be finally created. That is, in the case of performing double exposure, when an isolated line is placed in a region of a periodic pattern overlapping a fine line in a direction different from the period on the normal exposure mask, the line width of the isolated line is slightly larger than the line width of the fine line. By performing the optical proximity correction (OPC) to increase the thickness, the resolution can be enhanced, and a good image can be created even in a pattern having fine lines different from the periodic direction.

This effect is not limited to the case where the light-shielding pattern described above is created, but the same applies to the case where a pattern is created in the light-transmitting portion as shown in FIG. FIG.
Although the periodic pattern shown in FIG. 4B and the normal exposure pattern are used, the isolated line portion placed in the periodic pattern shown in FIG. 4B is slightly thicker than the fine line. As can be understood from the above description, by changing the line width of the periodic pattern from the fine lines of the normal exposure pattern, the optical proximity effect can be corrected, and a good composite image can be obtained. is there.

[Embodiment 2] In Embodiment 2, a case where pattern distortion due to the optical proximity effect is corrected by changing the shape of a periodic pattern with respect to a normal exposure pattern will be described with reference to FIG. I do. FIG. 6A shows an actually used periodic pattern and a normal exposure pattern. By combining these two patterns, FIG.
The purpose is to obtain a pattern having the same shape as the normal exposure pattern of the above. The periodic pattern described in the first embodiment (FIG.
6), the constriction may occur in the portion B of the normal exposure pattern in FIG. 6A depending on the line width and other conditions. Therefore, in the second embodiment,
The periodic pattern including the constriction correction will be described. The basic procedure for creating a periodic pattern is as in the first embodiment. The portion B is a boundary between a light shielding portion formed so as to overlap a fine line in the same direction as the periodic direction and a transmitting portion which is a periodic pattern, and constriction occurs due to the influence of light wraparound. . Therefore, the light shielding portion is configured as shown in the periodic pattern of FIG.
This constriction can be corrected by attaching an auxiliary pattern consisting of a light-shielding portion having the same 1 L angle as the width L of the fine line to the boundary portion to enlarge the light-shielding portion and to prevent light from flowing around.

FIG. 7 shows simulation results using the patterns of the second embodiment and the first embodiment. FIG.
FIG. 7 is a composite image before performing the necking correction shown in the first embodiment. FIG. 7 shows the case where an auxiliary pattern including a light-shielding portion for performing the necking correction is attached as described in the second embodiment.
It shows a composite image after double exposure. The dotted line is the layout of the desired pattern, and the solid line is the light intensity distribution obtained by simulation. According to this simulation result, the fine line in the same direction as the periodic direction can be obtained by using the periodic pattern of FIG. 6A in which an area difficult to resolve is resolved and an auxiliary pattern for preventing necking is used. It can be confirmed that even in the case of combining with the normal exposure pattern of FIG. Of course, the shape of the auxiliary pattern for correcting the constriction is not limited to that described here. In other words, in the case of performing double exposure, when placing an isolated line in a region of a periodic pattern that overlaps a fine line in a direction that is not orthogonal to the periodic direction on the normal exposure mask, in consideration of shortening of the isolated line due to the optical proximity effect, By partially expanding the shape of the isolated line so as to have a predetermined shape in advance, it becomes possible to satisfactorily reproduce the shape of the finally obtained composite image.

This effect is not limited to the case where the light-shielding pattern described above is formed, but is also the same when the pattern is formed by the light transmitting portion as shown in FIG. 6B. FIG.
The periodic pattern shown in FIG. 6B and the normal exposure pattern are used. In this case, too, the isolated line placed in the periodic pattern shown in FIG. By partially expanding the shape of the isolated line, the shape of the finally obtained composite image can be satisfactorily reproduced. In this way, by using a periodic pattern in which the shape of a region having no particular periodic structure is partially changed, the optical proximity effect due to light wraparound can be corrected, and the shape of the finally obtained composite image can be corrected. Can be improved.

[Embodiment 3] In Embodiment 3, a light-shielding portion is provided in a periodic pattern to adjust the amount of light so that only a desired pattern is obtained. An example will be described with reference to FIG. FIG. 8A shows a part of the T gate pattern shown in FIG. Finally, the purpose is to obtain a pattern having the same shape as the normal exposure pattern shown in FIG. When performing double exposure using the pattern shown in FIG. 8A as a normal exposure pattern,
Here, paying attention to the fine line and creating a periodic pattern based on the concept of the first embodiment in order to reproduce the fine line satisfactorily, it is necessary to use a periodic pattern like the periodic pattern 1 in FIG. There is. Here, it should be noted that a fine line can be created in the central part of the periodic pattern as long as adjacent phases are inverted. However, since the pattern is created in the light transmitting portion, if the pattern at the central portion is too large, the light amount at the central portion becomes larger than the light amount of the fine line,
When a double-exposure composite image is created, the pattern at the center also remains, so that only a desired fine line cannot be obtained. Therefore, as in the third embodiment, FIG.
As shown in the periodic pattern 2 of (a), a part of the large pattern is shielded from light, and the periodic pattern is composed of fine lines, so that the entire amount of light must be uniform. However, it is necessary to use a pattern such as the periodic pattern 2 in FIG. 8A in order to invert adjacent phases and to make the line width of a large pattern as thin as a fine line. In other words, when creating a pattern in the light transmitting part, if there is a pattern with a line width larger than the fine line in an area other than the design pattern, a light shielding part is provided in this thick line width pattern and the light amount matches the fine line. Therefore, it is necessary to devise a periodic pattern. Furthermore, by eliminating the pattern with a thick line width, in addition to balancing the light amount, the effect of the phase shift mask can be enhanced.
Better reproduction is obtained. This effect is not limited to the case where the light transmission pattern described above is created,
The same applies to the case where a pattern is created with a light shielding portion as shown in FIG. The periodic pattern and the normal exposure pattern shown in FIG. 8B are used. In this case, when there is a pattern having a line width larger than the fine line, a light shielding portion is provided in the pattern having the larger line width to reduce the light amount of the fine line. It is necessary to devise a periodic pattern so that they match. However,
The line width indicated by C in FIG. 8B needs to be about 1.5 to 3 times larger than the fine line. This is because if the area of C is not large to some extent, the image performance of isolated lines is affected. In FIG. 8A, since a pattern is formed in the light transmitting portion, a fine line is formed by the effect of intensity 0 generated in the light transmitting region as the pattern portion and the light shielding region in the peripheral portion. Therefore, it is necessary to provide a light-shielding portion in a pattern with a large line width and make the peripheral portion close to zero in intensity by increasing the light-shielding portion. On the other hand, in FIG. 8B, since the pattern is formed by the light shielding portion, a fine line is formed by the effect of intensity 0 generated in the light shielding region as the pattern portion and the transmission region in the peripheral portion. Therefore, it is necessary to provide a light-shielding portion in a pattern having a large line width and make the light-transmitting region in the peripheral portion wider than that in the case of FIG. As described above, the optimum line width varies depending on the case. However, in order to balance the light quantity of the entire periodic pattern, the periodic pattern is formed by a pattern having a line width of 3 L or less when the fine line is L. Since the entire line width is constant, even better patterns can be obtained by combining the periodic pattern in FIG. 8 and the normal exposure pattern in FIG.

[Embodiment 4] In Embodiment 4, a light-shielding portion is provided in a periodic pattern.
FIG. 9 illustrates an example in which the light amount of the entire periodic pattern is adjusted, and a pattern is created by a light shielding unit. Finally, the purpose is to obtain a pattern having the same shape as the normal exposure pattern in FIG. Since the pitch of the normal exposure pattern is shifted, a case where a continuous periodic pattern cannot be used is taken as an example. When performing double exposure using the pattern shown in FIG. 9 as a normal exposure pattern, attention is paid here to fine lines, and the periodic patterns shown in FIG. 9 are arranged so that the fine lines can be reproduced well.

It should be noted that the phases of adjacent periodic patterns need to be inverted in order to form a fine line. In that respect, the two periodic patterns in FIG. 9 have the same configuration. . However, in the periodic pattern 1, only the line width of the central phase 0 pattern is thick, and only this portion transmits much light. For this reason, the amount of light between the fine lines and the thick pattern may change significantly, which may adversely affect the synthesized image. Therefore, as in the case of the periodic pattern 2, since the periodic patterns used in the double exposure are all configured with the same line width, a light shielding portion is provided in an area where the line width of the periodic pattern is large, so that the balance of the light amount of the entire periodic pattern can be balanced. It can be adjusted and a good composite image can be obtained by double exposure.
Further, the effect of the phase shift can be enhanced.

[Embodiment 5] In Embodiment 5, a light-shielding portion is provided in a periodic pattern.
FIG. 10 illustrates an example in which the light amount of the entire periodic pattern is adjusted, and a pattern is created by a light transmitting portion, as an example. The pattern to be finally created is the pattern shown in FIG. When performing double exposure using the pattern shown in FIG. 10 as a normal exposure pattern, attention is paid here to fine lines, and the periodic pattern in FIG. 10 is such that the phases are arranged so that the fine lines can be reproduced well.

It should be noted that the periodic pattern 1 and the periodic pattern in FIG. 10 are the same because the phases of the adjacent periodic patterns are inverted in order to form a fine line. However, in the periodic pattern 1, the oblique line area is thick, and only a large amount of light passes through this area. For this reason, the amount of light between the fine lines and the thick pattern may change significantly, which may adversely affect the synthesized image. In particular, when a pattern is created in the light transmitting portion, a region having a large line width transmits a large amount of light, and a portion that is not originally required remains as a pattern. Therefore, as in the case of the periodic pattern 2, since the periodic patterns used in the double exposure are all configured with the same line width, a light shielding portion is provided in an area where the line width of the periodic pattern is large, so that the balance of the light amount of the entire periodic pattern can be balanced. It can be adjusted and a good composite image can be obtained by double exposure.

Sixth Embodiment In a sixth embodiment, another pattern example in which fine lines exist vertically and horizontally will be described. Finally, the purpose is to obtain a pattern having the same shape as the normal exposure pattern in FIG. In the normal exposure pattern shown in FIG. 11, fine lines exist both in the vertical and horizontal directions, and the interval between the fine lines is equal to or less than the resolution. In order to create such a pattern, it is necessary to use a periodic pattern as shown in FIG. This periodic pattern needs to include a region of a fine line having a resolution equal to or less than the resolution in the normal exposure pattern and a region where the interval between adjacent patterns is smaller than the resolution. In the case of the pattern of the sixth embodiment, the normal exposure pattern is a fine line region and a region where patterns are adjacent at intervals smaller than the resolution. Therefore, the region of the periodic pattern is equal to or larger than the same region as the normal exposure pattern.

Here, the periodic pattern 1 on the left side of FIG.
Aims to improve the resolution by overlapping edges on the fine line portion so as to resolve the fine line of the normal exposure pattern in FIG. FIG. 12 shows a simulation result of a composite image of the periodic pattern 1 and the periodic pattern 2 shown in FIG. 11, each periodic pattern, and a normal exposure pattern. The dotted line is the pattern that one actually wants to create, and the solid line is the light intensity distribution of the composite image calculated by simulation. Looking at the simulation result of FIG. 12,
In the light intensity distribution of the periodic pattern 1 in FIG. 11, undulations are generated in orthogonal fine lines, and the undulations are clearly seen in the image after the double exposure in FIG. Since this undulation causes disconnection, it is not practically preferable. In order to eliminate the undulation of the fine lines, a periodic pattern in which a part of the light transmitting portion forming the edge is shielded as shown in FIG. As shown in (1) and (2), a good image in which the undulation of fine lines was eliminated was obtained.

FIG. 13 shows the effect of this periodic pattern.
This will be described with reference to FIG. The purpose of such a pattern is to form a fine line by using an edge effect by phase inversion. In the case of the periodic pattern 1 in FIG. 13, focusing on the L-shaped corner, an edge effect due to the opposite phase occurs between A and B, B and C, and B and D. A and B or B in other parts
Edge effect occurs in the same direction as that between D and D, but in the L-shaped portion, the effect in the diagonal direction of B and C is also added, so that the edge effect due to phase inversion occurs double at the L-shaped corner. Since the strength is concentrated, undulations occur in the fine lines. On the other hand, the periodic pattern 2 in FIG. 13 is a case where a part of the light transmitting portion forming the edge is shielded. In this case, the L-shaped angle is generated between A and B and between B and D. It is created using the edge effect of the light transmitting part and the light shielding part. Since the edge effect that occurs in the oblique direction, which causes the intensity concentration in the periodic pattern 1, is eliminated, the undulation can be eliminated.

Actually, the edges overlapping with the normal exposure pattern are two in the center of FIG. 11, but adding one edge to the periphery thereof not only improves the resolution of the fine line, but also improves the edge of the fine line. The pattern of the square contact hole connection can be satisfactorily resolved. As described above, in order to resolve the L-shaped fine lines arranged in parallel, an L-shaped phase shift mask edge type is used. By removing the concentration, a good composite image can be obtained. In this case, the pattern line width is not limited to the edge type, and if the pitch of the period is 2L, 0 <period pattern line width ≦ 2
L is sufficient. Therefore, this L-shaped pattern can be created even by using the Levenson-type pattern shown in FIG. 14, and in this case as well, the vicinity of the intersection of the L-shape is shielded from light by Cr, and good intensity is prevented. A composite image can be obtained.

[Embodiment 7] This embodiment 7 is an example of a pattern in which fine lines are present vertically and horizontally and is in contact with a T-shape. It will be described using FIG. Finally, the purpose is to obtain a pattern having the same shape as the normal exposure pattern in FIG. The normal exposure pattern of FIG.
Fine lines exist both in the vertical and horizontal directions, and are adjacent to each other at an interval equal to or less than the resolution. In order to create such a pattern, it is necessary to use a periodic pattern as shown in FIG. As in Example 1, using a periodic pattern of Figure 15 periodic pattern 1, one direction, the periodic pattern
An isolated line is provided for a fine line in the same direction as the periodic direction of (1 ). Here, the periodic pattern 1 in FIG.
The aim is to improve the resolution by superimposing a periodic pattern on the fine line portion so as to resolve the fine line of the normal exposure pattern.

FIG. 16 shows a simulation result of a composite image of the periodic pattern 1 and the periodic pattern 2 shown in FIG. 15, each periodic pattern and a normal exposure pattern. Each is a light intensity distribution of a periodic pattern, a normal exposure pattern, and a composite image after double exposure from the top. The dotted line is a pattern to be actually created, and the solid line is calculated by simulation. Looking at this simulation result, it can be seen from the light intensity distribution of the periodic pattern in FIG. 16 that the light intensity is concentrated at the portion where the T-shaped crosses, and that the pattern is considerably thicker than the design value. Therefore, even in the composite image, the portion where the T-shaped crosses is large. Therefore, a good reproduction can be obtained by providing a light shielding portion at the base of the T-shape as in the periodic pattern 2 in FIG. FIG. 16 shows the result.
Comparing the simulation results with different periodic patterns in FIG. 16, it can be seen that in FIG. 16, the T-shaped roundness is eliminated and a good image is obtained.

Further, as in the case of the periodic pattern 3, a light-shielding portion may be provided at the intersection of the T characters. In this case, in the periodic pattern of FIG. 16, the intersection of the T character is dented, but since the normal exposure pattern is rounded, by performing double exposure, the contact portion of the T character in the composite image of FIG. The reproduction becomes better. In FIG. 16, the fine line of the T-shaped contact portion of the composite image is swollen to the left, but by using the periodic pattern 3, the swelling of the T-shaped contact portion can be eliminated. In this case, the periodic pattern may be not only a predetermined shape but also an overcorrected periodic pattern such as + for correcting a normal pattern. By doing so, even if the light intensity distribution of the periodic pattern slightly deviates from the predetermined shape, the composite image after the double exposure can be formed into the predetermined shape. As described above, by providing the light-shielding portion at the base of the T-shape or by providing the light-shielding portion at the intersection of the T-shape, it is possible to improve the reproduction of the contact portion of the T-shape.

The embodiments have been described above.
In the present invention, by using the periodic pattern devised as described above, it is possible to correct the pattern distortion due to the optical proximity effect even in a pattern in which the directions of the fine lines are mixed, and to obtain a good composite image. You can get it. The case of the L-shaped pattern in the sixth embodiment and the case of the T-shaped pattern in the seventh embodiment have been described, but the pattern is not limited to this shape.
When patterns intersect, it is needless to say that distortion of the pattern can be removed by providing a light shielding portion at or near the intersection. In the case where an image is formed by oblique incidence illumination using a binary mask, an effect similar to that of a phase shift mask can be obtained with respect to a periodic pattern. In the case of the first embodiment, a pattern example in which a periodic pattern is created by oblique incidence illumination uses a binary mask having no phase of the pattern shown in FIG. In the other embodiments, the same effect can be obtained by using a binary mask having no phase, and by inverting the light-shielding portion and the transmitting portion, the same effect can be obtained even in the case of a negative resist or a positive resist.

FIG. 17 is a schematic view showing a high-resolution exposure apparatus capable of performing both exposure for two-beam interference of a synchronous pattern and ordinary projection exposure to which the present invention can be applied. In FIG. 17, reference numeral 221 denotes a KrF or ArF excimer laser, 222
Is an illumination optical system, 223 is a mask (reticle), 224 is a mask stage, 227 is a projection optical system for reducing and projecting the circuit pattern of the mask 223 onto the wafer 228, 225 is a mask (reticle) changer, and the stage 224.
In order to selectively supply a normal reticle and one of the aforementioned Levenson-type phase shift mask (reticle), edge shifter-type mask (reticle), or periodic pattern mask (reticle) having no phase shifter. . Reference numeral 229 in FIG. 17 denotes one XYZ stage shared by the two-beam interference exposure and the projection exposure.
Reference numeral 9 denotes a plane orthogonal to the optical axis of the optical system 227 and is movable in the direction of the optical axis.
The position in the direction is precisely controlled. The apparatus in FIG. 17 includes a reticle positioning optical system (not shown) and a wafer positioning optical system (off-axis positioning optical system, TTL positioning optical system, and TTR positioning optical system). The illumination optical system 222 of the apparatus in FIG. 17 is configured to be able to switch between partially coherent illumination and coherent illumination. In the case of coherent illumination, the illumination optical system 222 of the above-described (1a) or (1b) shown in the block 230 is used. The illumination light,
It is supplied to one of the above-mentioned Levenson-type phase shift reticles, edge shifter-type reticles, or periodic pattern reticles having no phase shifter. In the case of partial coherent illumination, the illumination light of (2) shown in block 230 is supplied. Supply to desired reticle. Switching from partially coherent illumination to coherent illumination typically involves switching the optical system 222
The aperture stop placed immediately after the fly-eye lens may be replaced with a coherent illumination stop having an aperture diameter sufficiently smaller than this aperture stop.

FIG. 18 is a schematic view of an X-ray exposure apparatus. Using such an exposure apparatus, exposure can be performed by the method of this embodiment. A semiconductor chip such as an IC or an LSI using the exposure method and the exposure apparatus described above;
Display elements such as liquid crystal panels, detection elements such as magnetic heads, C
Various devices such as an image sensor such as a CD can be manufactured. It should be noted that the present invention is not limited to the above-described embodiments and examples, and various changes can be made without departing from the spirit of the present invention.

[0044]

As described above, according to the present invention, when performing multiple exposure of a pattern having a periodic structure and a normal exposure pattern, correction of pattern distortion due to the optical proximity effect is performed on the pattern having a periodic structure. By taking such measures, a good composite image can be obtained.

[Brief description of the drawings]

FIG. 1 is a view for explaining a case where no problem occurs in the pattern arrangement of double exposure.

FIG. 2 is a diagram for explaining a case where fine lines in different directions are mixed in a pattern arrangement of double exposure, which causes a problem.

FIG. 3 is a view showing a flowchart of double exposure.

4A and 4B are diagrams illustrating a procedure for creating a periodic pattern according to the first embodiment of the present invention. FIG. 4A illustrates a case in which a pattern is created in a light shielding unit, and FIG. 4B illustrates a case in which a pattern is created in a light transmitting unit. FIG.

FIG. 5 is a diagram showing a periodic pattern creation procedure according to the first embodiment of the present invention.

FIGS. 6A and 6B are diagrams showing a procedure for creating a periodic pattern according to the second embodiment of the present invention. FIG. 6A shows a case where a pattern is created by a light-shielding part, and FIG. FIG.

FIG. 7 is a diagram showing a simulation result in the second embodiment of the present invention.

FIGS. 8A and 8B are diagrams showing a procedure for creating a periodic pattern according to the third embodiment of the present invention, wherein FIG. 8A shows a case where a pattern is created by a light transmitting portion, and FIG. FIG.

FIG. 9 is a diagram showing a procedure for creating a periodic pattern according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a procedure for creating a periodic pattern according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a procedure for creating a periodic pattern in a sixth embodiment of the present invention.

FIG. 12 is a diagram showing a simulation result in the sixth embodiment of the present invention.

FIG. 13 is a diagram for explaining an effect of a periodic pattern according to the sixth embodiment of the present invention.

FIG. 14 is a diagram showing a procedure for creating a periodic pattern when a Levenson-type pattern is used according to a sixth embodiment of the present invention.

FIG. 15 is a diagram showing a procedure for creating a periodic pattern in a seventh embodiment of the present invention.

FIG. 16 is a diagram showing a simulation result in the seventh embodiment of the present invention.

FIG. 17 is a schematic view of a high-resolution exposure apparatus that performs double exposure.

FIG. 18 is a schematic diagram of an X-ray exposure apparatus.

FIG. 19 is a diagram showing a configuration of a conventional X-ray proximity exposure apparatus.

FIG. 20 is a view for explaining the principle of double exposure.

FIG. 21 is a view for explaining the principle of double exposure.

[Explanation of symbols]

 1: X-ray source such as SOR 2: SOR X-ray 3: convex mirror 4: beryllium thin film 5: focal plane shutter 7: object to be exposed 10: mask 221: KrF or ArF excimer laser 222: illumination optical system 223: mask 224: mask stage 227: projection optical system 228: wafer 229: XYZ stage

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-11-143085 (JP, A) JP-A-7-211619 (JP, A) JP-A-11-176726 (JP, A) JP-A-11-116 67640 (JP, A) JP-A-2000-150366 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 1/08 G03F 7/20

Claims (18)

(57) [Claims] 1. An exposure method for performing multiple exposure on a substrate to be exposed including exposure using a first pattern and exposure using a second pattern, wherein the first pattern has a period for resolving fine lines. A pattern having a structure , wherein an area without the periodic structure is formed in the first pattern for correcting pattern distortion due to an optical proximity effect in the exposure of the second pattern. Method. 2. The exposure method according to claim 1, wherein the second pattern has a multi-value light intensity distribution on a wafer surface. Wherein the second pattern, design pattern itself or, it the exposure method according to claim 1 or claim 2, characterized in that is close. Wherein said first pattern, claim 1-3, characterized in that to correct the pattern distortion due to the optical proximity effect as the light intensity distribution becomes closer to the shape of the design pattern 2. The exposure method according to item 1. 5. The method according to claim 1, wherein the pattern distortion is corrected by the optical proximity effect so that a light intensity distribution of a composite image obtained by exposing the first pattern and the second pattern is close to a design pattern. The exposure method according to any one of claims 1 to 4 , wherein Wherein a said periodic structure without <br/> region of the first pattern was thickened partially linewidth region, thereby correcting the pattern distortion due <br/> the optical proximity effect the exposure method according to any one of claims 2-5, characterized in that to perform. 7. The free <br/> region of said periodic structure of the first pattern, the direction of the fine lines not perpendicular to the direction of the period of the periodic structure of the first pattern of the second pattern 7. The exposure method according to claim 6 , wherein an isolated line is formed in a region overlapping with the second pattern, and a line width of the isolated line is made larger than a line width of the fine line of the second pattern. 8. The isolated line is formed such that a fine line of a composite image created from a periodic portion in the first pattern and a fine line of a composite image created from the isolated line have the same line width. The exposure method according to claim 7 , wherein the line width of the isolated line is optimized. 9. A method according to claim 2, wherein a correction pattern is formed in a region of said first pattern where said periodic structure is not present , and correction of pattern distortion due to said optical proximity effect is performed.
6. The exposure method according to any one of 5 . Wherein said correction pattern is the no periodic structure areas of the first pattern, the same as the direction of the period of the periodic structure of the first pattern of the second pattern
Flip the formed isolated line so as to overlap with the direction of fine line exposure method according to claim 9, characterized in that it is formed into a predetermined shape in anticipation of shorter該孤prostatic. 11. The first pattern exposure method according to claim 1 which is a pattern of thick line width more than three times the second pattern fine line of the light shielding portion is provided, characterized by a light amount adjustment . Wherein said first pattern, by adjusting the line width of the pattern exposure method according to claim 1, characterized in that to adjust the light amount balance of the overall pattern of the first. 13. The exposure method according to claim 1 , wherein when an intersecting pattern is used in the first pattern, a light-shielding portion is provided at or near the intersection. 14. The exposure method according to claim 1 , wherein when an L-shaped pattern is used as the first pattern, a light-shielding portion is provided at or near the intersection. 15. The exposure method according to claim 1 , wherein when a pattern orthogonal to a T-shape is used as the first pattern, a light-shielding portion is provided at or near the intersection. 16. The apparatus according to claim 1, wherein the first pattern is a periodic pattern having a period of 2 or more, and is formed of one of a Levenson type phase shift mask and a binary type mask. Any one of ~ 15
Exposure method according to item. 17. The method according to claim 1, wherein
An exposure apparatus having a multiple exposure mode for performing an exposure method . 18. using the exposure method according to any one of claims 1-16, device manufacturing method characterized by producing a device.