JP2000349010A - Method and apparatus for exposure as well as manufacture of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a fine line in any direction even when fine lines in a plurality of directions are mixed in an ordinary exposure pattern by a method wherein, out of a first pattern, a fine line in the direction different from the periodic direction of a periodic pattern constitutes a second pattern so as not to be overlapped with the periodic pattern. SOLUTION: A multiple exposure operation wherein an exposure operation by a first pattern in which fine lines in a plurality of directions are mixed so as to exist and an exposure operation by a second pattern which comprises a periodic pattern are contained is performed to a substrate to be exposed. The periodic direction of the periodic pattern is made to agree with a direction which is placed side by side with a fine line in a prescribed direction. A pattern in at least a part of the prescribed pattern or the boundary between patterns or a part of the fine line is exposed in the same position. Then, the fine line in the direction different from the periodic direction of the periodic pattern out of the first pattern constitutes the second pattern so as not to be overlapped with the periodic pattern.

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 double-exposing 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, when devices such as ICs, LSIs, and liquid crystal panels are manufactured by photolithography, a circuit pattern of a photomask or a reticle (hereinafter, referred to as a "mask") is projected onto a projection optical system. A projection exposure method and a projection exposure apparatus are used for projecting onto a photosensitive substrate such as a silicon wafer or a glass plate or the like (hereinafter, referred to as a “wafer”) coated with a photoresist or the like and transferring (exposing) the same onto the photosensitive substrate. ing. In response to the high integration of the above devices, it is required to miniaturize the pattern transferred to the wafer, that is, to increase the resolution, and increase the area of one chip on the wafer. In the projection exposure method and the projection exposure apparatus, the resolution and the exposure area are now being improved in order to form an image having a dimension (line width) of 0.5 μm or less over a wide range.

FIG. 23 shows a schematic view of a conventional projection exposure apparatus. In FIG. 23, 191 is an excimer laser which is a light source for exposure to far ultraviolet rays, 192 is an illumination optical system, 193 is illumination light,
Reference numeral 194 denotes a mask, 195 denotes an object-side exposure light that exits the mask 194 and enters the optical system 196, 196 denotes a reduction projection optical system, 197 denotes an image-side exposure light that exits the optical system 196 and enters the substrate 198, and 198 denotes a photosensitive element. Wafer as a substrate, 199
Denotes a substrate stage for holding a photosensitive substrate. The laser light emitted from the excimer laser 191 is guided to the illumination optical system 192 by the drawing optical system, and
The predetermined light intensity distribution, light distribution, and opening angle (numerical aperture N
A) The mask 194 is adjusted so as to have the illumination light 193 having, for example, A). On the mask 194, a pattern having a size obtained by reciprocally multiplying (for example, 2 times, 4 times, or 5 times) the fine pattern formed on the wafer 198 by a projection magnification of the projection optical system 196 is formed on a quartz substrate by chrome or the like. The illumination light 193 is transmitted and diffracted by the fine pattern of the mask 194, and becomes the object side exposure light 195. Projection optical system 19
6 is a method for projecting the object side exposure light 195 to the fine pattern of the mask 194 at the above projection magnification and with a sufficiently small aberration.
8 is converted into image-side exposure light 197 that forms an image on 8. The image side exposure light 197 converges on the wafer 198 at a predetermined numerical aperture NA (= sin θ) as shown in the enlarged view in the lower part of FIG. 23, and forms an image of a fine pattern on the wafer 198. The substrate stage 199 has a plurality of different areas (shot areas: areas to be one or more chips) of the wafer 198.
When a fine pattern is sequentially formed on the wafer 198, the wafer 198 is moved stepwise along the image plane of the projection optical system.
Is changed with respect to the projection optical system 196.

However, it is difficult for a projection exposure apparatus which uses the above-mentioned excimer laser as a light source to form a pattern of 0.15 μm or less. Projection optical system 1
96 has a resolution limit due to a trade-off between optical resolution and depth of focus due to the exposure wavelength used. The resolution R of the resolution pattern and the depth of focus DOF by the projection exposure apparatus are represented by the following Rayleigh formulas (1) and (2).

R = k ₁ (λ / NA) (1) DOF = k ₂ (λ / NA ² ) (2) where λ is the exposure wavelength, and NA is the brightness of the projection optical system 196. The numerical aperture on the image side, k ₁ , and k ₂ are constants determined by the development process characteristics of the wafer 198 and the like.
The value is about 0.7. From the equations (1) and (2), it is apparent that the numerical aperture N
Although there is a “high NA” that increases A, the depth of focus DOF of the projection optical system 196 needs to be set to a certain value or more in actual exposure. It can be seen that, in order to increase the resolution, it is necessary to “short-wavelength” the exposure wavelength λ to be eventually reduced.

However, as the wavelength is shortened, a serious problem occurs. This problem is that the glass material of the lens of the projection optical system 196 runs out. The transmittance of most glass materials is close to 0 in the deep ultraviolet region, and fused quartz currently exists as a glass material manufactured for an exposure apparatus (exposure wavelength: about 248 nm) using a special manufacturing method. Also, the wavelength sharply decreases for an exposure wavelength of 193 nm or less, and it is extremely difficult to develop a practical glass material in an exposure wavelength of 150 nm or less corresponding to a fine pattern of 0.15 μm or less. In addition, the glass material used in the deep ultraviolet region must satisfy a plurality of conditions such as durability, uniformity of refractive index, optical distortion, workability, etc., in addition to transmittance. Existence is at stake.

As described above, in the conventional projection exposure method and projection exposure apparatus, it is necessary to shorten the exposure wavelength to about 150 nm or less in order to form a pattern of 0.15 μm or less on the wafer 198, Since there is no practical glass material in this wavelength region, the wafer 198 has a thickness of 0.15 μm.
m or less could not be formed.

For this reason, recently, the exposure method and the exposure apparatus for performing double exposure of a periodic pattern exposure and a normal exposure on a substrate to be exposed (photosensitive substrate) have been proposed.
Creation of a circuit pattern having a portion of 15 μm or less has been studied. 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.

[0009]

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 matches the periodic direction in FIG. 1, no particular problem occurs. However, as a normal exposure pattern, when the direction of the fine lines is mixed, for example, when a pattern in which fine lines in the same direction as the period shown in FIG. 2 and fine lines in the vertical direction are mixed, the period is the same as the period. Fine lines in the direction can be resolved without any problem, but fine lines in the direction perpendicular to the period may not be resolved.

This point will be described with reference to FIGS. 1 and 2 on the assumption that a positive resist is used, taking patterns called a gate pattern and a T gate pattern as examples. In the figure, it is assumed that light is transmitted through all the periodic patterns and the phases are inverted. The periodic pattern has a period number of 2 or more, and the normal pattern has a constant phase and binary amplitude, in which light is transmitted to the periphery and the pattern portion is shielded. For example, in FIG. 1, since the direction of the fine line of the gate pattern which is the normal exposure pattern of FIG. 1 matches the direction of the periodic pattern of FIG. 1, the resolution of the fine line of the gate pattern which is the normal exposure pattern of FIG. Can be improved. next,
For example, in the case of the T gate pattern shown in FIG. 2 in which the fine lines of the gate pattern are provided with fine lines orthogonal to the T type, the directions of the fine lines are mixed.

As described above, when fine lines are mixed in the vertical direction and the horizontal direction, an area where the pattern is adjacent to the fine line at an interval equal to or less than the resolution is an area where resolution is particularly difficult. In order to increase the resolution of this area, it is necessary to use a periodic pattern as shown in FIG.
However, if only this periodic pattern is used, an area in which resolution is difficult cannot be resolved, but a fine line in a direction orthogonal to the period cannot be resolved. Therefore, when performing double exposure of the periodic pattern and the normal exposure pattern,
Patterns that can be created may be limited depending on the direction of the periodic pattern used. In particular, it has been difficult to cope with a pattern having fine lines in a direction different from the periodic direction of the periodic pattern by the conventional double exposure method.

Accordingly, the present invention solves the above-mentioned problems, and even in the case where fine lines are mixed in a plurality of directions in a normal exposure pattern, the periodic pattern is devised so that any direction in the normal exposure pattern can be improved. It is an object of the present invention to provide an exposure method by double exposure, an exposure apparatus, and a device manufacturing method, which can also resolve fine lines of the above and can obtain a good pattern.

[0013]

According to the present invention, an exposure method, an exposure apparatus, a device manufacturing method, and a device manufacturing apparatus are configured as follows to achieve the above object. It is. In other words, the exposure method of the present invention includes the steps of: exposing a substrate to be exposed to a first pattern in which fine lines in a plurality of directions are mixed;
An exposure method for performing multiple exposure including exposure by a pattern, wherein a direction of a cycle of the periodic pattern is made to coincide with a direction in which the fine lines in the predetermined direction are arranged, and at least a part of the periodic pattern, To expose the boundary and a part of the fine line at the same position,
The second pattern is characterized in that fine lines in a direction different from the direction of the cycle of the periodic pattern in the first pattern do not overlap with the periodic pattern. Further, the exposure method of the present invention, on the substrate to be exposed,
An exposure method for performing multiple exposure including exposure using a first pattern in which fine lines in a plurality of directions are mixed and exposure using a second pattern including a periodic pattern, wherein the direction of the cycle of the periodic pattern is defined as a fine direction in the predetermined direction. The first pattern is aligned with a direction in which the lines are arranged, and at least a part of the periodic pattern is exposed at the same position as a light shielding area or a phase boundary acting as a light shielding area and a part of the fine line. Of the above, the second pattern is characterized in that fine lines in a direction different from the direction of the period of the periodic pattern do not overlap the periodic pattern. Further, the exposure method of the present invention is characterized in that the direction of the period of the periodic pattern coincides with the direction in which many fine lines in the predetermined direction are arranged. Further, in the exposure method of the present invention, the periodic pattern is a periodic pattern having a period of 2 or more, and is formed of any one of a Levenson-type phase shift mask, an edge-type phase shift mask, and a binary type mask. It is characterized by being done. Also,
In the exposure method of the present invention, in the periodic pattern region in which the periodic pattern is not arranged, an isolated line is overlapped with a fine line in a direction different from the direction of the periodic pattern in the normal exposure pattern. It is characterized by being arranged. Further, the exposure method of the present invention is characterized in that the periodic pattern and the isolated line are formed in a light shielding portion or a light transmitting portion. Further, the exposure method of the present invention is characterized in that the isolated line has a shape different in size or shape in correspondence with a fine line of a normal exposure pattern in a direction different from the direction of the period of the periodic pattern. . Further, the exposure method of the present invention is characterized in that the normal exposure pattern in a direction different from the direction of the cycle of the periodic pattern includes a pattern whose line width is equal to or larger than the resolution.

The exposure apparatus of the present invention provides an exposure mode for performing multiple exposures including a first pattern in which fine lines in a plurality of directions coexist on a substrate to be exposed and a second pattern including a periodic pattern. In the exposure apparatus having, the direction of the period of the periodic pattern coincides with the direction in which the predetermined direction fine lines are aligned, at least a part of the periodic pattern, the boundary between the pattern or pattern and the fine line A part of the first pattern was exposed at the same position, and the second pattern was formed such that, among the first patterns, fine lines in a direction different from the direction of the period of the periodic pattern did not overlap with the periodic pattern. It is characterized by: Further, the exposure apparatus of the present invention includes an exposure apparatus that performs exposure on a substrate to be exposed by a first pattern in which fine lines in a plurality of directions are mixed.
An exposure apparatus for performing multiple exposure including exposure by a second pattern including a periodic pattern, wherein a direction of a period of the periodic pattern is aligned with a direction in which the fine lines in the predetermined direction are arranged, and at least a part of the periodic pattern is provided. A part of the fine line is exposed at the same position as a light-shielding region or a phase boundary acting as a light-shielding region, and the fine pattern in the direction different from the direction of the period of the periodic pattern in the first pattern. The second pattern is configured so that lines do not overlap with the periodic pattern. Further, the exposure apparatus of the present invention is characterized in that the direction of the period of the periodic pattern coincides with the direction in which many fine lines in the predetermined direction are arranged. Further, in the exposure apparatus of the present invention, the periodic pattern is a periodic pattern having a cycle number of 2 or more, and is configured by any one of a Levenson type phase shift mask, an edge type phase shift mask, and a binary type mask. It is characterized by being. Further, the exposure apparatus of the present invention is arranged such that the periodic pattern region in which the periodic pattern is not arranged is isolated from the normal exposure pattern so as to overlap with a fine line in a direction different from the direction of the period of the periodic pattern. It is characterized in that the lines are arranged. Further, the exposure apparatus of the present invention is characterized in that the periodic pattern and the isolated line are formed by a light shielding portion or a light transmitting portion. Further, the exposure apparatus of the present invention is characterized in that the isolated line has a shape different in size or shape in correspondence with a fine line of a normal exposure pattern in a direction different from the direction of the period of the periodic pattern. . Further, the exposure apparatus of the present invention is characterized in that the normal exposure pattern in a direction different from the direction of the period of the periodic pattern includes a pattern whose line width is equal to or larger than the resolution. Further, a device manufacturing method of the present invention is characterized in that a device is manufactured using any of the above-described exposure methods of the present invention or using any of the above-described exposure apparatuses of the present invention.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, even when fine lines are mixed in a plurality of directions in a normal exposure pattern, fine lines in both directions can be resolved by a structure in which the above-described periodic pattern is devised. Pattern can be obtained. Since the double exposure aims at improving the resolution by exposing two patterns at the same position, all the periodic patterns used here are designed according to the shape of the normal exposure pattern. As will be described in detail in the embodiment, an example of a T-gate pattern which determines a periodic pattern from a normal exposure pattern in the case of a positive resist forming a pattern in a light-shielding portion will be described with reference to FIG. The normal exposure pattern described at the top is the same as that in FIG. 2, in which fine lines in the same direction as the period and fine lines in the vertical direction are mixed, and the normal exposure pattern in which the patterns are adjacent at intervals smaller than the resolution is used. It is.

When the periodic pattern is determined in accordance with the normal exposure pattern, first, as shown in the periodic pattern 1 of FIG. 3, the direction of the periodic pattern is changed to the direction of the normal exposure pattern with many fine lines or the normal pattern of FIG. The direction where the resolution is difficult is determined in the direction of the period in which the resolution is difficult as shown in the exposure pattern, and the periodic pattern is arranged focusing on the fine lines and the region in which the resolution is difficult. Here, the area that is difficult to resolve is
This is an area where patterns are adjacent to each other at an interval equal to or less than the resolution, or a pattern having a line width equal to or less than the resolution is adjacent at an interval equal to or less than the resolution. Here, it is desirable that the length of the periodic pattern is equal to or longer than the length of the fine line in the normal exposure pattern.

Next, as shown in the periodic pattern 2 in FIG. 3, the area corresponding to the fine line in the direction orthogonal to this cycle is a large pattern, and the phase including the large pattern is alternately set to 0 · π. Set. In FIG. 3, the light transmitting part is shown in white and the light shielding part is shown in black. Furthermore, periodic pattern 3 in FIG.
As shown in (1), the same region as the fine portion in the direction orthogonal to this cycle is shielded from light by Cr. With this light-shielding portion, an isolated line is formed in the periodic pattern in a direction orthogonal to the period, and by performing exposure overlapping with the normal exposure pattern, a fine line portion in the direction orthogonal to the period can be resolved.

The periodic pattern 3 thus created
By using, a good image can be obtained even in the normal exposure pattern in which the periodic directions shown in FIG. 3 are mixed. In other words, when creating a periodic pattern in accordance with the normal exposure pattern, first, the direction of the normal exposure pattern with many fine lines or the direction of the period that can resolve a region where resolution is difficult is defined as the direction of the periodic pattern. The periodic pattern is arranged so that an area where resolution is difficult can be resolved. Then, a periodic pattern is not arranged in a region where a fine line in a direction orthogonal to the period exists, and one large pattern is formed. Here, the phase of the periodic pattern must be set so that 0 and π are alternately included including this large pattern. Furthermore, in the normal exposure pattern, it is necessary to provide a light-shielding portion of Cr, that is, an isolated line, for resolving a fine line region in a direction orthogonal to this period.

As described above, in the exposure method for performing the double exposure of the normal exposure pattern and the periodic pattern, the normal exposure pattern is a pattern in which fine lines exist in both the vertical and horizontal directions. It is used for resolving an area where resolution is difficult, and a periodic pattern in one of the vertical and horizontal directions is used. -No periodic pattern should be placed in the periodic pattern area that overlaps the fine line in a direction different from the period. -To provide an isolated line in order to resolve a fine line portion in a direction different from the period. By using a periodic pattern devised as described above, a good composite image can be obtained even in a pattern in which fine lines in the same direction as the period and fine lines in the vertical direction are mixed.

Although a positive resist in which a pattern is formed in the light-shielding portion has been described as an example, a similar effect can be achieved in the case of a negative resist in which a pattern is formed in the light-transmitting portion. Specific arrangements and the like of the patterns, including those details, will be described in Examples.

[0021]

Embodiments 1 and 2 relate to the present invention in the case of a positive resist forming a pattern in a light-shielding portion, and in Embodiment 3 in the case of a negative resist forming a pattern in a light-transmitting portion. Will be described. First, a flowchart of the double exposure method is shown in FIG. In the figure, the flow of each block of periodic pattern exposure, continuous exposure, and development is shown, but the order of the periodic pattern exposure and the normal exposure may be as shown in FIG. 4 or vice versa. When the exposure step is included, the exposure step can be performed alternately. Further, a step of performing precise alignment is performed on each exposure step side, but details regarding this processing are omitted. In the present embodiment, KrF 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 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. 25 (2) or (3) shows a circuit pattern (lithographic 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. 24 shows an exposure amount distribution at each exposure stage. Numerical values shown in the drawing of FIG. 24 represent the exposure amount on the resist. In FIG. 24, FIG.
4 (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. 24 (2) 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.
When these exposures are performed by double exposure without going through the development process, a distribution of the sum of the respective exposure amounts is formed 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 shown by a thick line in FIG. 24 (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 where the exposure amount equal to or more 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 of the normal exposure is formed, which overlaps the exposure patterns of the normal exposure and the periodic pattern exposure. Is done.

FIG. 25 shows a pattern and a mask for forming the exposure distribution shown in FIG. FIG.
Reference numeral 5 (1) denotes a pattern and a mask in which a repetitive pattern occurs 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.
24 with 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. In this case, a mask on which the gate pattern shown in FIG. 25B 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, FIG.
When the pattern and mask shown in (2) are exposed,
The multi-level exposure distribution shown in FIG. 24 (2) 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 can be 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.

As an advantage of the double exposure method, 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.

In the following embodiment, the wavelength is 248 nm.
Each specific example in which the periodic pattern is devised when performing double exposure of periodic pattern exposure and normal exposure using the krF excimer stepper described above will be described. [Embodiment 1] In Embodiment 1, a case where a Levenson phase shift mask is used as a periodic pattern will be described.
This will be described with reference to FIGS. FIG. 3 shows a procedure for creating a periodic pattern according to a normal exposure pattern. FIG. 5 shows an actually used periodic pattern and a normal exposure pattern. The purpose of combining these two patterns is to finally obtain a pattern having the same shape as the normal exposure pattern in FIG. is there.

The normal exposure pattern shown in FIG. 3 has four fine lines in the vertical direction and two fine lines in the horizontal direction.
Also, especially in the area where resolution is difficult, as shown in the figure,
This is the part where the patterns contact each other at an interval equal to or less than the resolution. Therefore, the periodic direction is set to the vertical direction in which an area where many fine lines exist and resolution is difficult can be resolved. 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
It is indispensable to arrange the periodic pattern in the area shown in FIG. 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 a direction orthogonal to the period exists is formed in a large pattern, and the periodic pattern is not arranged. This is because, if a periodic pattern is arranged here, a fine line in a direction orthogonal to the period will be constricted. 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, a periodic pattern area overlapping with a fine line in a direction orthogonal to the cycle is shielded by Cr so that light is not transmitted and an isolated light-shielded pattern is formed. The periodic pattern 3 created in this manner is a periodic pattern to be finally used.
Here, since the pattern is formed by the light-shielding portion, the light-shielding portion is provided to resolve a fine line in a direction orthogonal to the period. Therefore, the light-shielding portion may be slightly thicker, such as 2 L to 3 L, when the line width of the fine line of the pattern actually desired to be created is 1 L, for the purpose of preventing light from flowing around.

Also, the pattern line widths constituting the period need not be equal to the pattern intervals, and the pattern line widths may be made wider and there may be no intervals. In this case, as shown in the second embodiment, the pattern line width may be 0 <the periodic pattern line width ≦ 2L. As described above, a method is used in which a region that is difficult to resolve can be resolved by using a periodic pattern, and fine lines in a direction orthogonal to the period can be resolved by providing a light-shielding isolated line. 5 and the normal exposure pattern of FIG.
Even a pattern having fine lines different from the periodic direction can be satisfactorily formed.

FIG. 8 shows a simulation result when a normal exposure method and the method of the first embodiment are used. The dotted line in the figure indicates a desired pattern, and the solid line indicates an image obtained by simulation. As shown in the figure, an image close to a desired shape is obtained by using the present embodiment, and a portion difficult to resolve is well separated.

[Embodiment 2] In Embodiment 2, a case where a phase shift mask edge type is used as a periodic pattern will be described with reference to FIGS. With the phase shift mask edge type, the light intensity at the portion where the opposite phase pattern is in contact is close to 0, and the same effect as the Levenson phase shift mask shown in the first embodiment is obtained. The periphery of the pattern may be shielded or light may be transmitted.

FIG. 6 shows a procedure for creating a periodic pattern according to a normal exposure pattern. FIG. 7 shows a periodic pattern and a normal exposure pattern which are actually used. The purpose of combining these two patterns is to finally obtain a pattern having the same shape as the normal exposure pattern of FIG. is there. This pattern is the same as in the first embodiment.

The normal exposure pattern shown in FIG. 6 has four fine lines in the vertical direction and two fine lines in the horizontal direction.
Also, especially in the area where resolution is difficult, as shown in the figure,
This is the part where the patterns contact each other at an interval equal to or less than the resolution. Therefore, the periodic direction is defined as a vertical direction in which an area where many fine lines exist and resolution is difficult can be resolved. In this way, focusing on the “regions where resolution is difficult” where the fine lines and the patterns are in contact with each other at an interval equal to or less than the resolution, and determining the edge arrangement so that they can be resolved, the portion shown in the periodic pattern 1 is obtained. It is necessary to arrange the edge at the edge. 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 a direction orthogonal to the period exists is formed in a large pattern so that no edge is arranged. This is because if an edge is arranged here, a fine line in a direction orthogonal to the period will be constricted. And including this big pattern,
The phase is set as shown in the periodic pattern 2 so that the phase of the adjacent patterns is opposite to 0 · π. Further, a periodic pattern area overlapping with a fine line in a direction orthogonal to the cycle is shielded by Cr so that light is not transmitted and an isolated light-shielded pattern is formed. That is, the edges of the light transmitting portion and the light shielding portion are used in the orthogonal direction. The effect caused by the phase inversion of the periodic pattern and the zero intensity portion provided by providing the light shielding portion are used as the pattern.

The periodic pattern 3 created as described above is the final periodic pattern to be used. Here, since the pattern is formed by the light-shielding portion, the light-shielding portion is provided to resolve a fine line in a direction orthogonal to the period. Therefore, for the purpose of preventing light from wrapping around, this light-shielding portion has a width of 2 L to 2 L when the line width of the fine line of the pattern to be actually created is 1 L.
In some cases, the thickness is slightly increased to 3L. By synthesizing the periodic pattern shown in FIG. 5 and the normal exposure pattern shown in FIG. 5 created by using such a method, a pattern including fine lines different from the periodic direction can be satisfactorily created.

[Third Embodiment] In a third embodiment, a case of a negative resist in which a pattern is formed by a light transmitting portion will be described with respect to the first embodiment. FIG. 9 shows a conventional example in the case of a negative resist in which a pattern is formed in a light transmitting portion. Similarly to the case of the positive resist, even in the case of the negative resist, if the direction of the fine line portion of the gate coincides with the direction of the periodic pattern, resolution can be performed without any problem. However, similar to a positive resist, there are fine lines in a direction different from the period, and it is difficult to cope with a conventional method when patterns are adjacent at intervals smaller than the resolution.
In the present embodiment, a negative resist for forming a pattern in the light transmitting portion is used as compared with the first embodiment.

FIG. 10 shows a procedure for creating a periodic pattern corresponding to a normal exposure pattern. FIG. 11 shows the periodic pattern of FIG. 11 and the normal exposure pattern of FIG. 11 which are actually used. By combining these two patterns, a pattern having the same shape as the normal exposure pattern can be finally obtained. Is the purpose. The normal exposure pattern shown in FIG. 10 has four vertical fine lines and two horizontal fine lines, similarly to FIG. 5 shown in the first embodiment. In addition, an area where resolution is particularly difficult is a part where paddans are in contact with each other at an interval equal to or less than the resolution as shown in the figure. Therefore, the periodic direction is defined as a vertical direction in which an area where many fine lines exist and resolution is difficult can be resolved. in this way,
Focusing on “difficult-to-resolve” areas where fine lines and patterns are in contact at intervals smaller than the resolution, and determining the arrangement of the periodic patterns so that they can be resolved, the periodic pattern 1
It is indispensable to arrange the periods as follows.

Next, a periodic pattern is not arranged in a region where a fine line in a direction orthogonal to the period exists, and a light shielding portion is formed so as to have the same light intensity as the normal exposure pattern. This is because, if a periodic pattern is arranged here, a fine line in a direction orthogonal to the period will be constricted. Then, the phases are set as shown in the periodic pattern 2 so that the phases of the adjacent patterns are opposite to 0 · π. In the case of the positive resist described in the first embodiment, the pattern region of the normal exposure pattern is a light-shielding portion, and the portions other than the pattern region are light-transmitting portions. Therefore, the periodic pattern was not arranged in the region where the fine lines in the direction orthogonal to the period existed, and instead, the light transmitting portion was the same as the region other than the normal exposure pattern region.
However, in the case of the negative resist of this embodiment, the pattern region of the normal exposure pattern is a light transmitting portion, and other portions than the pattern region are light shielding portions of Cr. Therefore, a periodic pattern is not arranged in a region where a fine line in a direction orthogonal to the period exists, and this region is used as a light shielding portion.

Next, a light transmitting portion is arranged in a periodic pattern area overlapping with a fine line having a force direction orthogonal to the period so that light can be transmitted. The periodic pattern 3 created in this manner is a periodic pattern to be finally used. Here, since the pattern is formed by the light transmitting portion, an isolated line composed of the light transmitting portion is provided in order to resolve a fine line in a direction orthogonal to the period. Therefore, the light transmitting portion may be slightly thicker, such as 2 L to 3 L, when the line width of the pattern to be actually created is 1 L, for the purpose of preventing light from wrapping around.
Further, the line width of the periodic pattern is not limited to L and may be 0 <the line width of the periodic pattern ≦ 2L. As described above, no periodic pattern is arranged in a region where a fine line in a direction orthogonal to the period exists. Instead, an isolated line including a light transmitting portion in the case of a positive resist and a light shielding portion in the case of a negative resist is arranged. Will do. Therefore, even when using a negative resist,
By combining the periodic pattern of FIG. 11 shown in FIG. 11 with the normal exposure pattern of FIG. 11, it is possible to satisfactorily reproduce even a pattern having fine lines different from the periodic direction.

Fourth Embodiment In a fourth embodiment, a case will be described in which a periodic pattern is created by oblique illumination. When an image is formed by oblique incidence illumination using a binary mask, an effect equivalent to that of a phase shift mask can be obtained with respect to a periodic pattern. FIG. 12 shows a pattern example in the case where a periodic pattern is created by oblique incidence illumination. Although FIG. 12 assumes a positive resist, the negative resist is obtained by inverting the light transmitting part and the light shielding part of FIG. 12, and the same effect can be expected.

In the following fifth to ninth embodiments, examples of the configuration of a periodic pattern for resolving patterns other than the T gate pattern will be described. Even in a normal pattern other than the T gate pattern, the present invention is applied to a pattern composed of fine lines having a plurality of directions and a resolution equal to or less than the resolution. In particular, when a pattern larger than the fine line is adjacent to the fine line at an interval equal to or less than the resolution, it is difficult to separate the fine line because the fine line is drawn to the large pattern by the proximity effect. In this case, assuming that the resolution is 2L, the fine line is, for example, L
Width. The following example shows a case where a positive resist is applied.

Fifth Embodiment A fifth embodiment will be described with reference to FIGS. In FIG. 13B, the normal pattern is not a T-gate pattern, but the resolution is difficult at a portion where the same pattern as the T-gate pattern is hardly separated between adjacent patterns. As shown in FIG. 13A, a periodic pattern having two or more opposite-phase periods is arranged in a portion where separation is difficult, as shown in FIG. The number of periods may be increased by arranging a pattern of phase 0 next to a pattern having a phase of π and having no pattern. Where there is a fine pattern different from the direction of the period, a pattern with the same phase as the next periodic pattern is placed without placing the periodic pattern. An isolated pattern is provided.

In the case of such a normal pattern, adjacent patterns can be separated even if another periodic pattern is configured as shown in FIG. A pattern having a large phase opposite to that of an adjacent periodic pattern may be arranged in a portion having a fine pattern different from the direction of the period without placing the periodic pattern. The isolated pattern of the light-shielding portion larger than the pattern is provided. As described above, when a large pattern having the opposite phase is arranged, the image after multiple exposure obtained by the normal exposure and the periodic pattern exposure is different from the case where the large pattern having the same phase is arranged, but the patterns adjacent to both are separated. Is done. However, if the phases of the large left and right patterns sandwiching a portion overlapping with the fine pattern different from the direction of the period are set to be opposite to each other, the pattern of the same phase as the pattern of phase 0 in FIG. It becomes difficult to separate patterns in the image after multiple exposure. Even if the pattern is separated in the image after the multiple exposure, it is not preferable because the shape is distorted.

Embodiment 6 Embodiment 6 will be described with reference to FIG. The normal pattern is composed of fine lines having a plurality of directions and having a resolution equal to or smaller than the resolution, and the intervals between the individual patterns are smaller than the resolution. The patterns are not limited to those arranged orthogonally. In this case, assuming that the resolution is 2L, the fine line has, for example, an L width equal to or less than the resolution. In this embodiment, it is difficult to resolve a portion where a pattern larger than the fine line is adjacent to the fine line at an interval equal to or less than the resolution. In the same way as in the first embodiment, as shown in FIG. 15A, a periodic pattern having two or more opposite phases is arranged in a portion where separation is difficult. The number of periods may be increased by arranging a pattern of phase 0 next to a pattern having a phase of π and having no pattern.

In a portion having a fine pattern different from the direction of the period, a pattern having the same phase as the adjacent periodic pattern is arranged without placing the periodic pattern. An isolated pattern of a light-shielding portion larger than a predetermined pattern is provided. Alternatively, in a portion where a fine pattern different from the direction of the period exists, a pattern having a large phase opposite to that of the adjacent periodic pattern may be arranged without placing the periodic pattern (however, a portion overlapping the fine pattern different from the direction of the period). The large patterns on the left and right are separated from each other so that the phases of the large patterns are in phase with each other.

[Embodiment 7] In addition, the present invention is applied to a case in which a fine line having a plurality of directions and having a resolution equal to or smaller than the resolution is used and the interval between individual patterns is equal to or smaller than the resolution. In a seventh embodiment, an example of such a case will be described with reference to FIG. Assuming that the resolution is 2L as shown in FIG. 16 (2), the fine line has, for example, an L width equal to or smaller than the resolution. When a pattern having the same line width is adjacent to a fine line at an interval smaller than the resolution, the proximity effect is not large even if the interval is L smaller than the resolution. is there. However, if the distance is closer than L, the separation becomes difficult as in the previous embodiments. A periodic pattern when a normal pattern as shown in FIG. 16 (2) is resolved by multiple exposure is applied to a portion where resolution of a fine line is difficult according to the same concept as in the first embodiment as shown in FIG. 16 (1). A periodic pattern having two or more antiphase periods is arranged. The number of periods may be increased by arranging a pattern of phase 0 next to a pattern having a phase of π and having no pattern. Where there is a fine pattern different from the direction of the period, a large pattern with the same phase as the next periodic pattern is placed without placing the periodic pattern,
An isolated pattern of a light-shielding portion larger than a predetermined pattern is provided in a portion overlapping with a fine pattern different from the direction of the period.

In the case of such a normal pattern, if the structure of the periodic pattern is as shown in FIG. 14 (1), the image after multiple exposure is deteriorated. In the pattern as shown in FIG. 14A, the interaction between the pattern having the phase 0 and the large pattern having the phase π is caused as a proximity effect to the light shielding portion having no pattern portion, and the shape of the light shielding portion is distorted. In other words, since there is a phase inversion between the pattern of phase 0 and the large pattern of phase π, the boundary has zero intensity and a dark line is generated, but the boundary between the pattern of phase 0 and the large pattern of phase π. The intensity of the boundary with the light shielding portion becomes zero due to the presence of the light shielding portion. However, since the inclination of the dark line due to the phase inversion and the inclination of the dark line generated from the light-shielding portion are different, undulation occurs in the dark line, which affects the surroundings due to the proximity effect and causes the pattern of the light-shielded portion to be distorted. Therefore, when the pattern of the light-shielding portion of the periodic pattern is distorted, if the normal pattern overlapping this portion is a fine line, the distortion from the periodic pattern remains without disappearing even after the synthesis. The distortion of the fine line reduces the margin of the process such as the defocus and the exposure amount, and is liable to be broken. As in Example 5, if there is a thicker portion at the tip of the fine line, the strength of the portion becomes stronger, and the distortion occurring at the very tip of the fine line in the light-shielding portion of the periodic pattern is cancelled. Fine patterns different from the direction of the cycle of the composite image do not cause any problem because distortion disappears, but rather, the pattern of the light-shielded portion is attracted to the orthogonal pattern by the proximity effect from the dark line due to phase inversion, so these patterns Can be brought closer.

[Eighth Embodiment] An eighth embodiment will be described with reference to FIG. A periodic pattern when a normal pattern as shown in (2) of FIG.
As shown in FIG. 17A, in accordance with the same concept as in the first embodiment, a periodic pattern having two or more opposite phases is arranged in a portion where resolution of a fine line is difficult. Where there is a fine pattern different from the direction of the period, a large pattern having the same phase as that of the next periodic pattern is placed without placing the periodic pattern. An isolated pattern of a larger light shielding portion is provided.

[Embodiment 9] In addition, when there is a fine line having a resolution lower than the resolution and a pattern in a direction different from the direction of the fine line is formed, a pattern in a direction different from the direction of the fine line is lower than the resolution. However, the above method is applied even if the resolution is higher. In a ninth embodiment, an example of such a case will be described with reference to FIG. FIG.
Suppose a case where a pattern having a line width equal to or greater than the resolution in which the direction differs from that of a fine line as shown in (2) is mixed. As in the eighth embodiment, it is assumed that adjacent portions of the pattern are not particularly difficult to separate. When the normal pattern and the periodic pattern in only one direction are subjected to multiple exposure, the line width of the normal pattern in a direction different from the direction of the periodic pattern becomes non-uniform due to the image of the periodic pattern. In the case where uniformity of the line width is a problem, the periodic pattern of this embodiment may be used.

The periodic pattern when a normal pattern as shown in FIG. 18B is resolved by multiple exposure is shown in FIG.
As in (1), according to the same concept as in the first embodiment, a periodic pattern having a phase number of 2 or more in opposite phase is arranged in a portion where resolution of a fine line is difficult. In a portion where a pattern different from the direction of the cycle overlaps, an isolated pattern of a light shielding portion that is larger than a predetermined pattern is provided without placing a periodic pattern. If the pattern in a direction different from the direction of such a fine line is not lower than the resolution and is higher than the resolution, in a region where the periodic pattern is not placed, there is no need to arrange a large pattern having the same phase as the adjacent periodic pattern, It is only necessary to provide an isolated pattern of the light shielding portion without placing a periodic pattern.

FIGS. 19 and 2 show the effect of this embodiment.
Indicated by using 0. FIG. 19 shows the result of double exposure of the normal pattern and the periodic pattern in only one direction. Wavelength 2
48 nm, NA = 0.60 KrF exposure apparatus, 0.1
This is a resolution of a fine line pattern of 2 μm. FIG.
0 indicates that the periodic pattern is different from the normal pattern in that the isolated pattern of the light-shielding portion is larger than a predetermined pattern without placing the periodic pattern in a portion where a pattern different from the direction of the cycle overlaps as in the present embodiment. This is the result of double exposure. The synthesized patterns in FIGS. 19 and 20 resolve fine lines, and their lengths are less reduced. Also, as compared with FIG. 19, it can be seen that the composite pattern of FIG. 20 does not have a constricted curved pattern, and that the line width of a line having a resolution equal to or higher than that of a fine line is uniform.

The direction of the pattern different from the direction of the fine line is not limited to one direction, and even if there are patterns in a plurality of directions, it is sufficient to provide an isolated pattern of the light shielding portion in each direction. In the case of a pattern perpendicular to the direction of the periodic pattern, the uniformity of the line width is particularly deteriorated, but the direction of the pattern is not limited to the direction perpendicular to the direction of the periodic pattern. Further, when the fine line is sufficiently larger than the resolution, the light-shielding portion is not provided, and even if a continuous periodic pattern in one direction is used, the image of the multiple exposure does not deteriorate so much. The use of the periodic pattern is effective.

The fifth to ninth embodiments described above.
Has been described using a Levenson-type phase shift mask, but the same effect can be obtained by using an edge-type phase shift mask having the same pitch as described in the second embodiment. Alternatively, as in the fourth embodiment, the same effect can be obtained by inverting the light-shielding portion and the transmitting portion of the periodic pattern, using a binary mask having a constant phase, and using oblique illumination.

FIG. 21 is a schematic view showing a high-resolution exposure apparatus capable of performing both exposure for two-beam interference of a periodic pattern and ordinary projection exposure to which the present invention can be applied. In FIG. 21, 221 is 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. 21 denotes one XYZ stage shared by the two-beam interference exposure and the projection exposure. This stage 229 is movable on a plane orthogonal to the optical axis of the optical system 227 and in the optical axis direction. The position in the XY directions is accurately controlled using a laser interferometer or the like. 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 shown in FIG. 21 is configured to be able to switch between partially coherent illumination and coherent illumination. In the case of coherent illumination, the above-described (1a) or (1) shown in the block 230 is used. The illumination light of 1b) is supplied to one of the aforementioned Levenson-type phase shift reticles or edge shifter-type reticles or one of the periodic pattern reticles having no phase shifter, and is illustrated in a block 230 in the case of partial coherent illumination. (2)
Is supplied to a desired reticle. Switching from partial coherent illumination to coherent illumination can be achieved by replacing the aperture stop, which is usually placed immediately after the fly-eye lens of the optical system 222, with a coherent illumination stop having an aperture diameter sufficiently smaller than this aperture stop. .

Exposure can be performed by the method of the present embodiment using an X-ray exposure apparatus as shown in FIG.
2. Description of the Related Art Conventionally, an X-ray proximity exposure apparatus having a configuration shown in FIG.
No. 311). In FIG. 1, reference numeral 1 denotes an X-ray source (light emitting point) such as an SOR, and 2 denotes an SOR which spreads in a slit shape in the x direction.
The X-ray 3 is a convex mirror (for example, made of SiC) for enlarging the slit-shaped X-ray 2 in the y direction.
Reference numeral 7 denotes an object to be exposed such as a semiconductor wafer coated with a resist, and reference numeral 10 denotes a mask. Also, 4
Reference numeral 5 denotes a beryllium thin film for separating the atmosphere on the SOR side from the atmosphere on the side of 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. Using the above-described exposure method and exposure apparatus, IC. Various devices such as a semiconductor chip such as an LSI, a display element such as a liquid crystal panel, a detection element such as a magnetic head, and an imaging element such as a CCD can be manufactured.

Further, it is possible to perform exposure by the method of this embodiment using an X-ray exposure apparatus having a configuration as shown in FIG. The present invention is not limited to the embodiments described above, and can be variously modified without departing from the gist of the present invention. That is,
When a phase shift mask is used as the periodic pattern, an image is formed by utilizing the fact that the intensity of the periodic direction becomes zero due to the effect of the interaction of the phase inversion. By forming an image using the effect of intensity 0 generated in the portion, a good composite image can be obtained even in a pattern in which fine lines in the same direction as the period and fine lines in the vertical direction are mixed. .

[0063]

As described above, according to the present invention, when double exposure is performed using a normal exposure pattern and a periodic pattern, fine adjustment is made to the normal exposure pattern in a plurality of directions by modifying the periodic pattern. Even when lines are mixed, fine lines in any direction in the normal exposure pattern can be resolved, and 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 diagram showing a procedure for creating a periodic pattern according to the first embodiment of the present invention.

FIG. 4 is a view showing a flowchart of double exposure.

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

FIG. 6 is a diagram showing a periodic pattern creation procedure according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a procedure for creating a periodic pattern according to the second embodiment of the present invention.

FIG. 8 is a diagram showing simulation results in the case of using a normal exposure method and the method of the first embodiment.

FIG. 9 is a view for explaining a pattern arrangement of double exposure in a negative resist.

FIG. 10 is a diagram showing a procedure for creating a periodic pattern in a third embodiment of the present invention.

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

FIG. 12 is a diagram showing a procedure for creating a periodic pattern in a fourth embodiment of the present invention.

FIG. 13 is a diagram showing a procedure for creating a periodic pattern according to a fifth embodiment of the present invention.

FIG. 14 is a diagram showing a procedure for creating a periodic pattern in a fifth embodiment of the present invention.

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

FIG. 16 is a diagram showing a procedure for creating a periodic pattern in a seventh embodiment of the present invention.

FIG. 17 is a diagram showing a procedure for creating a periodic pattern in an eighth embodiment of the present invention.

FIG. 18 is a diagram showing a procedure for creating a periodic pattern in a ninth embodiment of the present invention.

FIG. 19 is a view for explaining the result of double exposure of a continuous periodic pattern and a normal pattern.

FIG. 20 is a view showing the results of Example 9 of the present invention.

FIG. 21 is a schematic diagram showing a high-resolution exposure apparatus capable of performing both exposure for two-beam interference of a periodic pattern and normal projection exposure.

FIG. 22 is a diagram showing a configuration of a conventional X-ray proximity exposure apparatus.

FIG. 23 is a schematic view of a conventional projection exposure apparatus.

FIG. 24 is a view for explaining the principle of double exposure.

FIG. 25 is a view for explaining the principle of double exposure.

FIG. 26 is a schematic diagram of an X-ray exposure apparatus.

[Explanation of symbols]

 1: X-ray source such as SOR 2: SOR X-ray 3: convex mirror 4: beryllium thin film 5: focal plane type shutter 7: object to be exposed 10: mask 191: excimer laser 192: illumination optical system 193: illumination light 194: Mask 195: Object side exposure light 196: Reduction projection optical system 197: Image side exposure light 198: Photosensitive substrate 199: Substrate stage 221: KrF or ArF excimer laser 222: Illumination optical system 223: Mask 224: Mask stage 227: Projection optics System 228: Wafer 229: XYZ stage

Claims (17)

[Claims] An exposure method for performing multiple exposure including exposure by a first pattern in which fine lines in a plurality of directions are mixed on a substrate to be exposed and exposure by a second pattern including a periodic pattern, wherein the periodic pattern The direction of the period is made to coincide with the direction in which the fine lines in the predetermined direction are aligned, so that at least a part of the periodic pattern, a boundary between patterns or patterns and a part of the fine line are exposed at the same position. The exposure method, wherein, in the first pattern, the second pattern is configured such that fine lines in a direction different from the direction of the period of the periodic pattern do not overlap with the periodic pattern. 2. An exposure method for performing multiple exposure including exposure by a first pattern in which fine lines in a plurality of directions are mixed on a substrate to be exposed and exposure by a second pattern including a periodic pattern, wherein the periodic pattern The direction of the period is matched with the direction in which the fine lines in the predetermined direction are lined up, and at least a part of the periodic pattern has a light shielding area or a phase boundary acting as a light shielding area and a part of the fine line at the same position. The second pattern is configured such that, among the first patterns, fine lines in a direction different from the direction of the period of the periodic pattern do not overlap with the periodic pattern. Method. 3. The exposure method according to claim 1, wherein the direction of the period of the periodic pattern coincides with a direction in which a large number of fine lines in the predetermined direction are arranged. 4. The periodic pattern according to claim 1, wherein the periodic pattern is a periodic pattern having two or more periods, and is formed of any one of a Levenson type phase shift mask, an edge type phase shift mask, and a binary type mask. The exposure method according to claim 1, wherein: 5. A periodic pattern region in which said periodic pattern is not arranged, wherein said normal exposure pattern includes
The exposure method according to any one of claims 1 to 4, wherein the isolated line is arranged so as to overlap a fine line in a direction different from the direction of the period of the periodic pattern. 6. The exposure method according to claim 5, wherein the periodic pattern and the isolated line are formed by a light shielding portion or a light transmitting portion. 7. The isolated line has a shape different in size or shape corresponding to a fine line of a normal exposure pattern in a direction different from the direction of the period of the periodic pattern. An exposure method according to claim 6. 8. The normal exposure pattern in a direction different from the direction of the period of the periodic pattern includes a pattern having a line width equal to or greater than the resolution of the pattern.
8. The exposure method according to any one of items 1 to 7. 9. An exposure apparatus having an exposure mode in which multiple exposures including a first pattern in which fine lines in a plurality of directions are mixed on a substrate to be exposed and a second pattern including a periodic pattern are performed. The direction of the cycle of the periodic pattern is made to coincide with the direction in which the predetermined direction fine lines are arranged, and at least a part of the periodic pattern, a boundary between patterns or patterns and a part of the fine lines are at the same position. An exposure apparatus, wherein the second pattern is configured such that fine lines in a direction different from a direction of a cycle of the periodic pattern in the first pattern do not overlap with the periodic pattern. . 10. An exposure apparatus for performing multiple exposures including a first pattern in which fine lines in a plurality of directions are mixed on a substrate to be exposed and a second pattern including a periodic pattern. The direction of the period is matched with the direction in which the fine lines in the predetermined direction are lined up, and at least a part of the periodic pattern has a light shielding area or a phase boundary acting as a light shielding area and a part of the fine line at the same position. The second pattern is configured such that, among the first patterns, fine lines in a direction different from the direction of the period of the periodic pattern do not overlap with the periodic pattern. apparatus. 11. The exposure apparatus according to claim 9, wherein the direction of the period of the periodic pattern coincides with the direction in which a large number of fine lines in the predetermined direction are arranged. 12. The periodic pattern according to claim 1, wherein the periodic pattern is a periodic pattern having two or more periods, and wherein a Levenson type phase shift mask is provided.
The exposure apparatus according to any one of claims 9 to 11, wherein the exposure apparatus comprises one of an edge-type phase shift mask and a binary-type mask. 13. A periodic pattern region in which the periodic pattern is not disposed, an isolated line is disposed in the normal exposure pattern so as to overlap a fine line in a direction different from the direction of the period of the periodic pattern. The exposure apparatus according to any one of claims 9 to 12, wherein: 14. The exposure apparatus according to claim 13, wherein the periodic pattern and the isolated line are formed by a light shielding portion or a light transmitting portion. 15. The method according to claim 13, wherein the isolated line has a shape different in size or shape in correspondence with a fine line of a normal exposure pattern in a direction different from the direction of the period of the periodic pattern. The exposure apparatus according to claim 14. 16. The normal exposure pattern in a direction different from the direction of the period of the periodic pattern includes a pattern having a line width larger than the resolution of the pattern. The exposure apparatus according to any one of the above items. 17. A device is manufactured by using the exposure method according to any one of claims 1 to 8 or using the exposure apparatus according to any one of claims 9 to 16. Characteristic device manufacturing method.