JP3188933B2 - Projection exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention illuminates a mask pattern.
Projection exposure method using an oblique incidence illumination system that forms a fine pattern by projecting onto a substrate such as a wafer using light and a projection lens
It is about the law .

[0002]

2. Description of the Related Art Conventionally, a projection exposure apparatus for forming a fine pattern such as an LSI has been required to have a high resolution, and has recently reached a resolution close to a theoretical limit determined by the wavelength of light. In recent years, in order to cope with further miniaturization of LSI patterns, one
A phase shift method has been proposed to improve the resolution by providing a phase difference close to 80 degrees so that the light intensity at the light-shielding portion approaches 0 to improve the resolution. However, in the phase shift method, a pattern having high periodicity, such as an L & S pattern (line-and-space pattern), in which a phase difference of 180 degrees can be obtained in an adjacent light transmitting portion, has a great effect of miniaturization. With a random pattern, the effect decreases as it becomes difficult to satisfy this condition. That is, the effect of improving the resolution differs depending on the type and arrangement of the patterns. For this reason, the phase shift method has many technical difficulties, such as an effective shifter arrangement method, a defect-free shifter manufacturing technique, and its inspection and repair techniques. Disadvantages, such as an increase in

On the other hand, Japanese Patent Application No. 3-99822 “fine pattern projection exposure apparatus” irradiates light incident on a reticle at an angle corresponding to the numerical aperture of a projection optical system from an optical axis to irradiate the light. This is an invention that achieves the same resolution as the phase shift method. This method has a great advantage over the phase shift method because the conventional mask can be used as it is. In order to illuminate the mask illumination light obliquely from the optical axis, Japanese Patent Application No. 3-157401, entitled "Fine Pattern Projection Exposure Method", invents and provides a light source such as a ring, four points or multiple points. In such oblique incidence illumination, only one side of the diffracted light diffracted by the mask pattern is used for image formation, so that the 0th-order diffracted light is approximately twice as large as the conventional method using double-sided diffracted light. Since this extra zero-order light causes a decrease in contrast, in Japanese Patent Application No. 3-157401 “fine pattern projection exposure method”, a portion corresponding to a light source shape which forms an image at an aperture stop position without a mask is disclosed. A method of arranging a 0th-order light adjustment filter around it is described in Japanese Patent Application No. Hei.
No. 7816, “Mask and Projection Exposure Method Using the Mask”, is a 0-order light adjustment mask in which the light shielding portion of the mask is translucent and the light transmitted through the light shielding portion has a phase difference of a half wavelength with the light transmitted through the transparent portion. , Thereby adjusting the 0-order light to improve the contrast.

[0004] Each of the oblique incidence illumination systems described above,
Giving a phase difference between adjacent patterns by oblique illumination,
Since the same resolution improvement effect as that of the phase shift method is obtained, high resolution can be obtained with a pattern with high periodicity, but random patterns with low periodicity and ends where the period of the periodic pattern ends, no periodicity In the case of an isolated pattern or a large pattern, there are disadvantages that the resolution is reduced or the image forming pattern is distorted.

[0005] First, the disadvantages of the conventional oblique illumination system will be described in comparison with the conventional illumination system. FIG. 13 shows a typical light source shape and a filter arrangement at an aperture stop for a conventional illumination and various oblique illumination methods,
9 shows standard optical parameters. Here, the radius of the aperture stop normalized by the numerical aperture (NA) of the projection lens is set to 1. The radius of the circular light source in the conventional illumination method is σ. In the circular light source and the light source of the zero-order light adjustment filter system, the radius to the center of the circular ring was R, and the width of the circular ring was 2σΔ. In the four-point light source, the radius up to the center of the point light source was R, and the diameter of the point light source was 2σΔ. In the filter of the aperture stop of the zero-order light adjustment filter system, the amplitude transmittance of the same annular portion as the light source image formed on the aperture stop was T1, and the portion outside the light source image was T2. In addition,
In the light source shape, the hatched part is the light source. The amplitude transmittance other than the hatched portion in the aperture stop is 1.0.

The present invention can exert its effects regardless of the wavelength (λ) of the light source and the numerical aperture (NA) of the projection lens used.
The dimensions of the pattern, the distance in the mask, and the amount of defocus used U and Z units standardized as follows. Unit of pattern dimensions and distance in mask: U = λ / 2 (NA) Unit of defocus amount: Z = λ / 2 (NA) ^{2 In the} following description, The standard parameters shown in FIG. 14 were used for each optical system. The defocus amounts were all set to four levels of 0, 1, 1.5 and twice as large as Z.

Next, a description will be given of the location of problems such as pattern distortion caused by a zero-order light adjustment filter system, which is a typical oblique illumination system to which the present invention is not applied, in comparison with the conventional illumination system. FIG. 14 (A), (B), (C), (D)
Is a typical periodic pattern, (E) and (F) are
FIG. 8 shows a simulation result of an exposure intensity profile when the present invention is not applied to a pattern having no periodicity. The periodic pattern is an L & S pattern (line and space pattern) consisting of 16 infinite lines.
Both the line and the space have a width of U. The horizontal axis is U
The vertical axis represents the distance in the pattern expressed in the unit of, and the normalized exposure intensity is standardized with the exposure intensity at the center of the large pattern being infinitely large as 1. The design value of the pattern edge is 4 in U units.
From 35 to 35, the deficit amount is shown by a solid line, a short dotted line, a long dotted line, and a dashed line for four levels of 0, 1, 1.5 and twice as large as Z, respectively.

Normally, in development, a pattern is formed when the exposure intensity is around the 0.3 level. Therefore, the lateral shift amount between the point where the exposure intensity profile intersects the level of the exposure intensity 0.3 and the design edge is small, that is, the pattern distortion is small, and how much the region with the small shift amount is above and below. It is important that the development margin is large, and that the margin does not decrease even if the defocus amount increases. Comparison between (A) and (B) shows that the conventional illumination method reduces the resolution as the defocus amount increases, reduces the development margin, and indicates that pattern formation is difficult. On the other hand, it can be seen that the zero-order light adjustment filter system shows a good resolution even when the defocus amount becomes large, and that a pattern can be formed with a large depth of focus. However, comparing the exposure intensities of the 16 patterns, the conventional illumination method is almost flat, whereas the 0th-order light adjustment filter method has a large change in the exposure intensity particularly at the end of the periodic pattern. These appear in the actual pattern formation as a result that the pattern width is different between the center part and the end part. (C), (D) is an enlarged view on the right side of (A), (B). In the zero-order light adjustment filter method, the exposure intensity profile due to defocusing in the rightmost pattern is noticeable. This means that in actual pattern formation, a pattern edge is displaced or a pattern shape is distorted, and that when development is fluctuated, a large dimensional change is caused.
The non-periodic patterns of (E) and (F) are 0 and 10 in units of U.
This is an infinite length pattern with design edges. The defocus condition is the same as the periodic pattern. In the exposure intensity profile (E) according to the conventional illumination method, there is almost no deviation due to defocus at the intersection of the standardized exposure intensity 0.3 and the design edge, whereas in the zero-order light adjustment filter method (F), the defocus amount is small. The displacement increases as the size increases. This is the actual pattern formation, where the pattern becomes thinner (for positive resist) or thicker (for negative resist).
Appears as.

[0009]

As described above,
In the oblique incidence illumination method, the exposure intensity is irregular or the exposure intensity profile is deformed in a portion where the period of the periodic pattern ends, and this has the disadvantage that the pattern is distorted or misaligned, and the accuracy is reduced.

[0010] The present invention has been made in view of the conventional problems as described above, it is an object to have your projection exposure by oblique incidence illumination method, the end of the cycle pattern and aperiodic Patan'ejji unit It is an object of the present invention to provide a projection exposure method capable of obtaining a fine and highly accurate pattern by removing or reducing a pattern distortion and a positional shift that occur in principle and improving a contrast.

[0011]

In order to achieve the above-mentioned object, a first aspect of the present invention is to provide a mask pattern in which illumination light and projection laser light are projected.
A slant that forms a fine pattern by projecting it on a substrate using a lens
In a projection exposure method using an incident illumination method , a target pattern having a periodicity in arrangement is provided, and when λ is the wavelength of the illumination light and NA is the numerical aperture of the projection lens, the width of the target pattern is λ / 2NA or more ,
0.8 × λ / 2NA to 1.4 × λ / 2N from the edge of the transmission part (or light-shielding part) where the cycle of the target pattern ends.
Preserve the periodicity of the target pattern at the pitch of A
One or more auxiliary patterns that cannot be resolved with the illumination light
By exposing the formed mask by oblique incidence illumination,
A target pattern is projected and exposed on a substrate . The second invention uses a mask pattern with illumination light and a projection lens.
Oblique incidence illumination that projects on the substrate and forms a fine pattern
In the projection exposure method according to the method , a target pattern including an isolated light transmitting portion having no periodicity in arrangement is provided, and λ is
When the wavelength of the illumination light, the NA numerical aperture of the projection lens, the width of the light transmitting portion and above the vicinity of lambda / 2NA,
On one or both sides of the light transmitting section, 0.8 × from Patan'ejji to the target λ / 2NA~1.2 × λ / 2NA
At this pitch, the periodicity is given to the target pattern.
A mask formed with one or more auxiliary patterns that cannot be resolved by the illumination light composed of a light transmitting portion (or a light shielding portion).
The target pattern is exposed to the substrate by exposure to illumination.
Is projected and exposed .

[0012]

The periodicity of the target pattern is promoted or imparted by the auxiliary pattern that cannot be resolved, thereby reducing the distortion of the exposure intensity profile of the imaging pattern and improving the contrast. This allows for finer,
A highly accurate pattern can be formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1A shows the basic arrangement of an auxiliary pattern group or auxiliary patterns according to the present invention in the case of a periodic pattern. Reference numeral 101 denotes a target pattern formed of a light transmitting portion, 102 denotes an auxiliary pattern group formed by a light transmitting portion according to the present invention, and 103 denotes an auxiliary pattern forming an auxiliary pattern group. The white part indicates the light transmitting part, and the hatched part indicates the light shielding part. Auxiliary pattern 10 at end where periodicity ends
By arranging the auxiliary pattern group 102 composed of 3 and creating conditions for maintaining the periodicity, distortion of the exposure intensity profile appearing at the end of the period of the oblique incidence illumination method is reduced. In this case, it is necessary to arrange the auxiliary pattern 103 so that the periodicity of the target pattern 101 is maintained even at the end portion, and that the auxiliary pattern 103 is an unresolvable auxiliary pattern or auxiliary pattern group that does not remain as a pattern after development. It is. For the former, a greater effect can be obtained by arranging as many auxiliary patterns 103 as possible within the width (Wa) of the auxiliary pattern group 102, where the width (Lo) of the auxiliary pattern 103 is as large as possible. However, for the latter, conversely, Lo is as small as possible, and the smaller the number of auxiliary patterns 103, the larger the development margin. Also, as can be seen from FIG.
In particular, since the exposure intensities of the first and second patterns from the end of the period are greatly affected, the auxiliary pattern group 10
The number of 2 is optimally about two, but the effect of the present invention can be obtained with one or three. Also, the auxiliary pattern group 102
If the number of the auxiliary patterns 103 is one or more, the effect of the present invention can be exhibited.

FIG. 2A shows a case where the present invention shown in FIG. 1A is applied. Pa = 2 × U, Lo = 0.25 at the right end of the same pattern as in FIGS. 14A and 14B. An exposure intensity profile based on a zero-order light adjustment mask method in which two auxiliary pattern groups each including two × U auxiliary patterns are arranged.
FIG. 2B shows an exposure intensity profile based on the zero-order light adjustment mask method when the present invention is not applied, which is shown for comparison, and is the same as FIG. 14D. From the comparison between the two,
It can be seen that the unevenness of the exposure intensity at the end of the period is improved, and in particular, the exposure intensity profile of the outermost pattern has hardly protruded. Further, since the exposure intensity by the auxiliary pattern group is 0.2 or less, the auxiliary pattern group does not remain as a pattern after development.

Next, an embodiment in which the basic arrangement of FIG. 1A is modified or applied will be described. FIG. 3A shows a case where a target periodic pattern is formed of a light shielding portion, and is a pattern obtained by inverting FIG. 1A. Reference numeral 301 denotes a target pattern including a light-shielding portion, 302 denotes an auxiliary pattern group including a light-shielding portion, and 303 denotes an auxiliary pattern that forms an auxiliary pattern group. In this case, by arranging the auxiliary pattern 303 or the auxiliary pattern group 302 composed of the light shielding part at the periodic end, contrary to the auxiliary pattern 103 composed of the light transmitting part in FIG. The same effect as described in (1) can be obtained.

FIG. 4A is an embodiment of FIG. 3A, and FIG.
Lc on the right side of the inverted pattern of the infinite length L & S pattern consisting of 16 lines of the same size as (A) or (B) of FIG.
= 0.2 × U, in which two sets of auxiliary patterns composed of two auxiliary patterns are arranged, and the exposure intensity profile is based on the zero-order light adjustment mask method.

FIG. 4B shows, for comparison, an example in which the auxiliary pattern according to the present invention is not applied to the same pattern. Focusing on the vicinity of the exposure intensity 0.3 at which a pattern is formed after development, when the present invention is not applied, the development in which the pattern edge protrudes inward as the defocus amount increases, is remarkable. It can be seen that the application has improved this considerably. Further, the exposure intensity by the auxiliary pattern is reduced to around 0.55, but has a sufficient margin with the exposure intensity of 0.3 formed by the pattern. As described above, the effect of the present invention and this development margin are incompatible. That is, if Lc is increased or the number of auxiliary patterns in the auxiliary pattern group is increased, the effect increases but the margin decreases. Accordingly, it is necessary to optimize the conditions of the auxiliary pattern arrangement in consideration of development.

FIG. 5 shows a modification of the basic arrangement shown in FIG. 1A, in which the auxiliary pattern group and the number of auxiliary patterns in the auxiliary pattern group are one. Lo = at both ends of five infinite length L & S
The exposure intensity by the 0th-order light adjustment mask method when one auxiliary pattern of 0.3 × U is arranged while changing Pa is shown. (A) shows the case where there is no auxiliary pattern, where the exposure intensity is uneven and the exposure intensity profile is exposed outside the patterns at both ends. Comparing (B) to (F),
The effect is greatest at (D) closest to Pa = P. The exposure intensity of each pattern is substantially equal, and particularly, the contrast of the patterns at both ends is improved, and the exposure intensity profile is reduced. (C) and (E) show that Pa is P-W / 2.
It is set in the range of <Pa <P + W / 2, and shows a relatively good effect. (B) or (F) is P
a is arranged under the condition of Pa <P−W / 2 and Pa> P + W / 2, and the effect of the present invention is small. In the arrangement according to the present invention, a high effect can be exhibited under the condition that Wa is equal to W as much as possible and Pa is equal to P as much as possible. Furthermore, when the number of auxiliary patterns in the auxiliary pattern group cannot be increased unavoidably, the highest effect is obtained under the condition of Pa = P, but Pa is P−W / 2 <Pa <P +
If the auxiliary pattern is arranged in the range of W / 2, the effect of the present invention can be obtained.

FIG. 3B is also a modification of the basic arrangement of FIG. 1A and is an example applied to the case where the auxiliary pattern group is composed of one auxiliary pattern and W> U. Reference numeral 304 denotes a target pattern including a light transmitting portion, and reference numeral 305 denotes an auxiliary pattern including a light transmitting portion. In this case, the auxiliary pattern 305 is arranged at a pitch S from the end of the target pattern 304 , and S is arranged as close to U as possible.

FIG. 6A shows an embodiment using this arrangement. Zero-order light when one auxiliary pattern consisting of S = 1.2 × U and Lo = 0.4 × U is arranged at the right end of nine L & S patterns consisting of W = 2 × U and P = 4 × U 3 shows an exposure intensity profile by an adjustment mask method. FIG.
(C) shows, for comparison, an exposure intensity profile by the zero-order light adjustment mask method when the present invention is not applied. According to the present invention, near the exposure intensity of 0.3, the projection of the exposure intensity profile due to an increase in defocus is suppressed, and the edge position shift is reduced. In this case, S is most effective near U, but 0.8 <S <
If the ratio is 1.4, the effect of the present invention is recognized. FIG.
(B) shows L at the center of the target pattern consisting of the endmost light transmitting portion.
It can be seen that, with the arrangement of the light shielding auxiliary pattern of c = 0.2 × U, the positional deviation of the outermost target pattern and the development margin are further improved as compared with FIG.

FIG. 1B shows the basic arrangement of auxiliary patterns according to the present invention when the target pattern is non-periodic. Reference numeral 104 denotes an auxiliary pattern including a light shielding unit, 10
Reference numeral 5 denotes an auxiliary pattern including a light transmitting portion. Focusing on the pattern edge, the pattern edge is given periodicity by this and the auxiliary pattern. The white portion indicates the light transmitting portion. In this case, the target pattern may be the light transmitting portion or the light shielding portion. FIGS. 7A and 7B show an application example of the present invention, in which Pb = U, Lo = 0.4 × U, Lc =
In (A), two auxiliary patterns are arranged on both sides, and in (B), one auxiliary pattern is arranged on both sides. FIG. 14C shows a case where the present invention shown for comparison is not applied.
Same as (F). After development, focusing on the exposure intensity around 0.3, which is a measure of pattern formation, as the defocus increases, the profile that has greatly protruded has been improved by applying the present invention, and almost no displacement has been seen. . It is also clear that the effect of two auxiliary patterns is greater than that of one auxiliary pattern on both sides, but if auxiliary patterns cannot be arranged around the pattern, one auxiliary pattern on each side or one auxiliary pattern on one side However, the effect of the present invention can be obtained.

FIG. 1C shows the basic arrangement of the auxiliary pattern according to the present invention when the target pattern is an isolated pattern. Reference numeral 106 denotes a target pattern including a light transmitting portion, 107 denotes an auxiliary pattern group, and 108 denotes an auxiliary pattern including a light transmitting portion. In this case, auxiliary patterns 108 are arranged on both sides of the isolated pattern, and periodicity is imparted to the isolated pattern having no periodicity. FIG. 8A shows an exposure intensity profile according to the embodiment shown in FIG. In this case, the auxiliary pattern group includes two auxiliary patterns, one on each side. FIG. 8B shows a case where the present invention is not applied for comparison. From the comparison between the two, it can be confirmed that the application of the present invention generally improves the contrast.

FIG. 9 shows an application example of the basic device shown in FIG.
A great effect can be obtained when the target pattern is formed of a light shielding portion. Reference numeral 901 denotes a target pattern including a light-shielding portion, and reference numeral 902 denotes an auxiliary pattern including a light-shielding portion. In this case, if W ≦ U, S
Is as close as possible to W, but if W> U, then S is preferably U
The closer to, the higher the effect.

FIG. 10A shows the exposure intensity profile of the embodiment shown in FIG. 9 using the zero-order light adjustment mask method. In this case, two auxiliary patterns are provided on each side. FIG. 10B shows a case where the present invention is not applied for comparison. From the comparison between the two, it can be confirmed that the application of the present invention generally improves the contrast.

As described above, in the application of the present invention to the isolated pattern shown in FIG. 1C, a periodicity is newly given by arranging an auxiliary pattern group or an auxiliary pattern on a pattern having no periodicity. In particular, an effect of improving the contrast can be obtained.

Next, the present invention has mainly been described so far.
A case where the present invention is applied to an oblique incidence illumination method other than the next light adjustment mask method will be described. FIGS. 11A and 11C are examples applied to a ring illumination system. The auxiliary pattern group arrangement is the same as that shown in FIGS. 2A and 4A in the zero-order light adjustment mask method. FIGS. 11B and 11D show a case where the present invention is not applied to FIGS. 11A and 11C and are shown for comparison. The same disadvantages as those described for the zero-order light adjustment mask method in the annular illumination method, that is, unevenness in the end pattern exposure intensity and the exposing of the exposure intensity profile have occurred, resulting in misalignment of the formed pattern and Deterioration of dimensional accuracy is caused.
It can be seen that by applying the auxiliary pattern group according to the present invention, the same effect as in the zero-order light adjustment mask method can be obtained.

FIGS. 12A and 12C show an example in which the present invention is applied to a four-point illumination system. The auxiliary pattern group arrangement is the same as that shown in FIGS. 2A and 4A in the zero-order light adjustment mask method. FIGS. 12B and 12D show a case where the present invention is not applied to FIGS. 12A and 12C and are shown for comparison. The four-point illumination method has the same disadvantages as those described in the 0th-order light adjustment mask method, that is, irregularity of the end pattern exposure intensity and the approach of the exposure intensity profile have occurred. By applying the same, an effect similar to that of the zero-order adjustment mask method is obtained. As described above, the present invention is effective in an oblique incidence illumination system using a so-called deformed light source such as annular illumination or four-point illumination.

[0028]

According to the present invention, projection exposure by an oblique illumination system is provided.
In the method, in the oblique incident illumination system, paying attention that the higher the periodicity of the pattern, the higher the resolution can be obtained, so that the periodicity is maintained at the periodic end where the periodicity of the target pattern is broken, and An auxiliary pattern or group of auxiliary patterns having unresolvable dimensions formed around or inside the target pattern so as to provide periodicity when the target pattern has no periodicity. Pattern forming accuracy can be improved. The pattern actually used in LSIs and the like is a two-dimensional pattern, and its shape and dimensions are infinite. Therefore, in the embodiment of the present invention, the effect is shown using a basic one-dimensional infinite length pattern. Have been. When the present invention is actually implemented in a two-dimensional pattern, it can be easily realized by applying the arrangement method of the auxiliary pattern or the auxiliary pattern group according to the present invention. If the performance or function of the LSI or the like is not affected even if the auxiliary pattern or the auxiliary pattern group remains, it is possible to obtain a high effect by increasing Lo and Lc described above.

[Brief description of the drawings]

FIGS. 1A, 1B and 1C are diagrams showing a basic arrangement of an auxiliary pattern group or an auxiliary pattern according to the present invention,
(A) shows a case where the target pattern has periodicity, (B) shows a case where the target pattern is non-periodic, and (C) shows a case where the target pattern is a non-periodic isolated pattern.

FIG. 2A shows an embodiment in which the present invention is applied to a periodic pattern, and FIG. 2B shows a case in which the present invention is not applied with the same pattern shown for comparison.

FIGS. 3A and 3B show an example of an arrangement of auxiliary patterns or auxiliary patterns according to the present invention, which is a modification or application of FIG. 1A.

FIG. 4 (A) is an example using FIG. 3 (A) which is an auxiliary pattern group arrangement according to the present invention, and FIG. 4 (B) is a case where the present invention is not applied with the same pattern shown for comparison. .

5 (B) to 5 (F) are examples using FIG. 3 (B), which is an auxiliary pattern group arrangement according to the present invention, and FIG. 5 (A) is the same pattern shown for comparison, and the present invention is applied. If not.

6 (A) and 6 (B) show an embodiment using FIG. 3 (B) which is an auxiliary pattern group arrangement according to the present invention, and FIG. 6 (C) shows the application of the present invention with the same pattern shown for comparison. If not.

7 (A) and 7 (B) are examples to which FIG. 1 (B), which is an auxiliary pattern arrangement according to the present invention when the target pattern is aperiodic, is applied, and FIG. 7 (C) is shown for comparison. This is a case where the present invention is not applied with the same pattern.

FIG. 8A is an auxiliary pattern arrangement according to the present invention when the target pattern is aperiodic and an isolated pattern; FIG.
(B) is a case where the present invention is not applied with the same pattern shown for comparison.

9 is an example of the arrangement of auxiliary patterns according to the present invention, which is an application of FIG. 1C, which is an auxiliary pattern arrangement according to the present invention when the target pattern is aperiodic and an isolated pattern.

FIG. 10A shows an embodiment using the auxiliary pattern arrangement according to the present invention shown in FIG. 9, and FIG. 10B shows a case where the present invention is not applied with the same pattern shown for comparison. .

FIGS. 11A and 11C show a case where the present invention is applied to an annular illumination method which is one of the oblique incident illumination methods, and FIGS. 11B and 11D respectively show (A) and (C). Is a case where the present invention is not applied with the same pattern shown for comparison.

12 (A) and 12 (C) show a case where the present invention is applied to a four-point illumination method which is one of the oblique incidence illumination methods, and FIGS. 12 (B) and (D) show (A) and (C), respectively. Is a case where the present invention is not applied with the same pattern shown for comparison.

FIG. 13 is a diagram showing a light source shape and a transmittance arrangement at an aperture stop in a conventional illumination method and various oblique illumination methods used for describing the present invention.

FIG. 14 is a diagram for explaining the problems of the conventional technology, and shows typical periodic patterns (A) to (D) in a conventional illumination method and a zero-order light adjustment filter method which is one of oblique incidence illumination methods. And exposure intensity profiles of aperiodic patterns (E) and (F).

[Explanation of symbols]

 101 target pattern 102 auxiliary pattern group 103 auxiliary pattern 301 target pattern 302 auxiliary pattern group 303 auxiliary pattern

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 1/08

Claims (2)

(57) [Claims] An illumination light and a projection lens are used for a mask pattern.
Oblique illumination that forms a fine pattern by projecting onto a substrate
In a projection exposure method using a bright method , a target pattern having a periodic arrangement is provided , and
Wavelength of serial illumination light, when the NA is numerical aperture of the projection lens, the width of the pattern to the objective lambda / 2NA around more
0.8 × λ / 2NA to 1.4 × from the edge of the transmission part ( or light-shielding part) where the cycle of the target pattern ends.
At the pitch of λ / 2NA, the periodicity of the target pattern is
An auxiliary pattern that cannot be resolved with the illumination light
Exposing one or more masks by oblique incidence illumination
And projecting the target pattern onto a substrate . 2. A pattern of a mask is formed by using illumination light and a projection lens.
Oblique illumination that forms a fine pattern by projecting onto a substrate
In the projection exposure method according to the bright mode, with a pattern of interest consisting of the light transmitting portion of the non-periodic orphaned arrangement, when the wavelength of λ of the illumination light, the NA is numerical aperture of the projection lens, the light The width of the transmission part is λ / 2
NA or more, on one or both sides of the light transmitting portion ,
0.8 × λ / 2NA~ from Patan'ejji to the object
1.2 × λ / 2NA pitch at the target pattern
Form one or more auxiliary patterns that cannot be resolved by the illumination light, which is composed of a light transmitting part (or light shielding part) so as to provide periodicity
By exposing the mask to oblique incidence illumination.
Throw, characterized in that the projection exposure the pattern in the substrate to be
Shadow exposure method.