JPH07176476A - Method and apparatus for exposing pattern, mask used therefor and semiconductor integrated circuit formed by using the same - Google Patents

Abstract

PURPOSE:To realize a resolution equivalent to a phase shifting method or more without generating a pattern impossible to design by using a pattern depending polarization mask for applying polarization characteristics responsive to a direction of the pattern on the mask to an illumination light passed through the pattern. CONSTITUTION:B0 B90, B180, B270 of partial lights of an illumination light respectively have linear polarizations, and emit a ring bandlike band like an illumination light 11 on a pupil of a reducing lens 31 of a projecting optical system when there is no mask 2. Patterns 11, 12, 13, 14 directed in directions (x) and (y) are, for example, formed on the mask 2 by lithography, and polarization characteristics responsive to the directions of the patterns are applied to a light emitted to and passed through the patterns. Thus, the pattern having much excellent resolution as compared with conventional resolution pattern can be exposed by using a projecting optical system of a conventional exposure apparatus as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of exposing a fine pattern, an exposure apparatus and a mask used for the method, and
The present invention relates to a semiconductor integrated circuit manufactured by this method, and more particularly to exposure of a pattern having a line width close to a pattern size limit determined by the diffraction limit of light used for exposure.

[0002]

2. Description of the Related Art As semiconductor integrated circuits are becoming finer, they are approaching a region determined by the diffraction limit of light. For this reason, various devices called the super-resolution technique have been made in recent years. If the resolution R of the exposure optical system is the exposure wavelength λ and the numerical aperture NA of the projection optical system, it is determined by R = k ₁ · λ / NA, and the conventional k ₁ is considered to have a limit of about 0.6 to 0.8. Was there.

The above-mentioned various measures have been attracting attention as a method of breaking the limit and solving the problem of the decrease in the depth of focus, which becomes more and more severe with miniaturization to some extent. As typical techniques, a phase shift method, an annular illumination method, a diagonal illumination method, etc. have been studied.

If the method of (1) is used, the phase of the pattern transmitted light between adjacent patterns of the repeated pattern is 180 ° with respect to each other.
By making them shift, the light intensity between adjacent patterns of the pattern formed by the projection optical system becomes 0, and the separation between the repeated patterns can be made very good. However, in this method, when the pattern becomes a two-dimensional pattern, the phase cannot be necessarily changed by 180 ° between the adjacent patterns, so that there is a portion that is not resolved as compared with the conventional exposure method. This imposes very large restrictions on pattern design, and undesignable patterns occur.

The conventional method is shown in FIG. 4 (a).
As shown in, the directivity σ of the illumination light (the ratio of the spread d of the illumination light on the pupil to the pupil diameter D of the projection optical system, that is, σ = d /
D) was set to about 0.5, the spread of the illumination light on the pupil was made into an annular shape as shown in FIG. 4 (b), and the outer and inner diameters of this annular area were compared with the pupil diameter D. The MTF (Moduration Transfer Function) in the high frequency region of the pattern is increased by setting them to about 0.7 and 0.5, respectively. As a result, the resolution is higher than that of the conventional illumination, but the resolution is lower than that of the phase shift method.

In the method (1), the spread of the illumination light on the pupil of the projection optical system is arranged diagonally at four points as shown in FIG. 4 (c). By doing this, a better resolution is obtained for the xy-direction pattern in the figure than in the annular illumination. However, the resolution of the pattern forming an angle of 45 ° with the xy directions is lower than that of the annular illumination, and the resolution is also lower than that of the conventional illumination of σ = 0.5.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the above-mentioned conventional methods, in particular, the various super-resolution methods which are currently being actively studied.

Here, the problems are summarized as follows. The phase shift method is the method of obtaining the highest resolution among the existing methods, but if it is attempted to maintain this resolution, there is a pattern that cannot be designed, which is a great obstacle in the LSI design and manufacturing. The annular illumination method of does not provide higher resolution than the method of. The method has a lower resolution than that of, and the resolution of the pattern in the xy direction is higher than that of the method, but the resolution of the pattern of xy and 45 ° is significantly deteriorated.

An object of the present invention is to solve such a problem and to realize a resolution equal to or higher than that of the phase shift method without generating a pattern which makes it impossible to design.

[0010]

In order to achieve the above object, in the present invention, the light from the exposure illumination light source has a desired directivity on a mask (or reticle) on which a desired original image pattern is drawn. Irradiate, project the transmitted light or reflected light of the mask on the object to be exposed through the projection optical system,
When exposing the image from the original pattern, the following means are applied.

That is, the directivity of the illuminating light is so-called annular illumination or direct illuminating, and a pattern-dependent polarization mask that imparts polarization characteristics according to the direction of the pattern on the mask to the illuminating light that has passed through this pattern. To use. At this time, the exposure light of the annular illumination or the oblique illumination on the pupil of the projection optical system may have its polarization state substantially rotationally symmetrical with respect to the center of the pupil when the mask is not provided. Also,
It is advisable to dispose a polarization element (or an analysis element) whose polarization state is substantially rotationally symmetrical with respect to the pupil center in the vicinity of the pupil of the projection optical system.

As the pattern-dependent polarization mask, a mask is used in which the tangential direction of the edge of the pattern on the mask and the polarization direction of the light of the illumination light transmitted (or reflected) through this pattern are substantially parallel or orthogonal to each other. . Further, the above-mentioned object is achieved by using the above-mentioned mask, in which the pattern on the mask is composed of a portion A that transmits (or reflects) illumination light and a portion B that slightly transmits (or reflects) but substantially blocks light (or hardly reflects). it can. At this time, the portion B that substantially shields the light from the portions A and B
The amplitude transmissivity (or amplitude reflectivity) is 30% of the amplitude transmissivity (or amplitude reflectivity) of the part A that is transmitted.
The following is recommended. In addition, the directivity of the annular illumination or the oblique illumination is such that one of ± 1st order light of the diffracted light from the minimum pattern on the mask illuminated by this irradiation light passes through the pupil of the projection optical system and the other. Keeps his eyes out.

The means for imparting the polarization characteristic on the mask can be realized by using an anisotropic medium, a minute polarization prism structure, a dichroic object, a minute slit structure, or the like.
Further, in this micro-polarization prism structure, a transparent object is covered on a film formed by multi-layer vapor deposition on the concave surface inclined from the edge of the pattern transmission part toward the center of the pattern transmission part, and the surface is processed to be flat. It can be realized by the structure. The minute slit structure is a structure in which a fine single line or a plurality of fine lines are drawn along the line of the edge of the pattern transmitting portion. Furthermore, this thin line is preferably made conductive.

By using the above method, a fine semiconductor integrated circuit having a pattern structure which cannot be realized by the phase shifter method is exposed. Further, the directivity of the conventional illumination light cannot be resolved by so-called annular illumination or direct illumination, and a fine semiconductor integrated circuit in which the pattern direction is not restricted is exposed.

That is, the pattern of the fine semiconductor integrated circuit includes at least a repetitive pattern, and the line width w or the repetitive pitch p of the repetitive pattern has an exposure wavelength of λ,
When the numerical aperture of the projection optical system is NA, 0.25λ / N
A <w <0.5λ / NA or 0.5λ / NA <p <
It satisfies 1.0λ / NA. In addition, the pattern of this fine semiconductor integrated circuit is almost 45 in two orthogonal directions.
A pattern having an angle of °, a pattern that cannot be exposed by the phase shifter method, and a repeating pattern. The line width w or the repeating pitch p of the repeating pattern has an exposure wavelength of λ, a projection optical system When the numerical aperture is NA, 0.25λ / NA <w <0.5λ / NA or 0.5λ / NA <p <1.0λ / NA is satisfied.

When the above-mentioned method is applied to a negative type resist, the mask of a portion where a pattern is to be formed becomes a light shielding portion, and after exposing the resist, this portion is removed by development,
The film in this portion is etched and removed by etching or the like. Therefore, for example, the above-described fine pattern that gives polarization characteristics is not formed in a portion where a pattern is desired to be formed, and this fine pattern is drawn in the peripheral portion that transmits light. If the pattern to be formed at this time is an isolated pattern, it is not necessary to draw this fine pattern in a wide range around this pattern, and this fine pattern can be formed in a range approximately equivalent to the width of the pattern resolved by this exposure optical system. It is enough to draw a fine pattern. Further, this is not limited to the isolated pattern. For example, even when there is no pattern near the outermost periphery of a portion where fine patterns are densely arranged, this exposure optical system is provided outside the outermost periphery. It suffices to draw this fine pattern in a range approximately equal to the width of the pattern to be resolved.

At the corners of the pattern which bend at a right angle and the tip of the pattern, there are cases in which a minute pattern for imparting polarization characteristics cannot impart sufficient polarization characteristics. In such a case, a 45 ° pattern or an arc-shaped fine pattern is drawn in the orthogonal direction at the corner or the tip.

Although high resolution can be obtained by using the above-mentioned method, for example, the pattern on the mask which gives the polarization characteristic is a pattern long in the x direction and its tip is close to the pattern long in the y direction. In such a case, the resolution may not be sufficient between the parts that are close to each other. This occurs, for example, in the case where the tip end of the putter has insufficient polarization characteristics for transmitting polarized light orthogonal to the side of the tip end and blocking parallel polarized light. For such a case, a reticle in which a phase shifter is applied to either the pattern (group) in the x direction or the y direction is used.

By exposing the isolated pattern using a mask having a pattern having the above-mentioned polarization characteristics and a polarized ring illumination, the conventional mask is used to expose with the directivity of the normal illumination, or the normal pattern is used. High resolution can be obtained compared with the case of exposing with annular illumination, but a minute pattern that has a phase difference of π from the phase of the transmitted light of this pattern is further provided around the pattern having this polarization characteristic. .

As will be described later in detail with reference to FIGS. 28 and 29, an exposure apparatus having a fixed numerical aperture NA and exposure wavelength of a projection lens is usually used. In this case, the exposure pattern It is possible to select the directivity of the above-mentioned polarized ring zone illumination according to the line width and set it as the condition that provides the highest resolution.

[0021]

The operation of the present invention will be described with reference to FIGS.

As shown in FIG. 5, in the case of a pattern long in the y direction, it is assumed that this pattern transmits linearly polarized light vibrating in the y direction, but does not transmit linearly polarized light in the x direction. The directivity of the illumination light that irradiates the mask on which this pattern is drawn is so-called zonal illumination or directional illumination. For example, in the case of the zonal illumination shown in the figure, the luminous flux B from each direction that illuminates this pattern. _1, when the _{B 2, B 3, B 4} , B 5, B 6, consider B _7, B _8, if these lights no mask, B ₁ on the pupil of each projection lens ', B _{2', B 3 ', B 4',} B 5 ',
B ₆ ', B _7', reaches the position of the B ₈ '.

Now, assuming that the polarizations of the eight light fluxes are perpendicular to the optical axis of the projection optical system and are orthogonal to the line passing through the optical axis, the light fluxes B ₁ and B ₅ of these eight light fluxes are in the y direction. However, the light fluxes of B ₃ and B ₇ hardly pass through this pattern. In addition, B ₂ , B ₄ , B ₆ , and B _{8 in the} middle pass almost 1/2. B ₁ and B light beam ₅ passed through the pattern, the principal ray reaches on B ₁ 'B ₅ and' pupil of the projection optical system. Further, the diffracted light spreads in the x direction around the 0th-order lights B ₁ 'and B ₅ '.

It is well known that high resolution can be obtained if the diffracted light in the x direction can pass through the pupil in a wide range. Therefore, in the present invention, the luminous fluxes of B ₁ and B ₅ almost pass through the pattern in the y direction and give a high resolution as described above, and the luminous fluxes of B ₃ and B ₇ are, as clearly understood from the above description, Although only the narrow range of the diffracted light above passes and the resolution is lowered, this light beam hardly passes through this pattern, so that it is possible to expose a fine pattern without lowering the resolution. Also, the light of B ₂ , B ₄ , B ₆ , and B ₈ is the above-mentioned conventional illumination light, and although the resolution is not as good as the luminous flux of B ₁ and B ₅ , the intensity of the passing light is halved. Because. The resolution due to the luminous fluxes of B ₁ and B ₅ becomes dominant.

As can be seen from the above description, in the present invention, since only the illumination light having the highest resolution is effectively used, the resolution which cannot be achieved by the above-mentioned conventional method can be obtained. Further, due to the polarization property of the illumination light and the polarization transmission property depending on the direction of the pattern, high resolution can be similarly realized not only for the pattern in the y direction but also for the pattern oriented in any direction. The fact that high resolution can be obtained without depending on the direction and arrangement of the patterns has not been realized by the phase shift method.

To compare the operation of the present invention with the conventional super-resolution method, the method and the pattern obtained by the present invention obtained by simulation are shown in FIGS. In order to demonstrate the effect of the present invention, the pattern width to be exposed is 0.25 μm, the exposure light is the i-line of a mercury lamp, and the wavelength is 36.
5 nm, the numerical aperture NA of the projection optical system is 0.57. FIG. 6 shows the case of annular illumination, and it can be seen that pattern separation is poor even at the focal point position.

FIG. 7 shows the case of oblique illumination with respect to the pattern in the xy directions, which is improved as compared with the annular illumination, but the pattern separation becomes worse at a defocus of 0.5 μm. However, in the pattern of 45 ° in the xy directions in FIG. 8, the resolution is deteriorated as compared with the annular illumination. FIG. 9 is a pattern obtained by the exposure method of the present invention with a normal mask, that is, a mask used in FIGS. 6, 7 and 8 in the case where the ratio of the transmissivity of the transmissive part to the light-shielding part is infinite. It can be seen that a good image is obtained in a wider focus range as compared with 7 and 8.

The pattern on the mask is composed of a portion A which transmits the illumination light and a portion B which slightly transmits the illumination light but substantially shields the light.
The light transmitted through A and B has the above-mentioned masks whose phases are different from each other by 180 °, and the resolution is further improved by subjecting the masks to annular illumination or oblique illumination. At this time, a high resolution can be obtained by setting the amplitude transmittance of the substantially light-shielding portion B for the portions A and B to be 30% or less of the amplitude transmittance of the transmitting portion A. Particularly, when it is set to about 22%, the separation between the patterns becomes the best.

This is because when the amplitude transmittance of the 0th-order light and the 1st-order light by the annular illumination or the directional illumination becomes 22% in the light shielding portion of the mask, the intensities of both lights become substantially equal to each other. This is because the contrast of interference due to is largest, that is, the separation of repetitive patterns is the best.

Further, if the mask of the present invention is used and the polarization state of the illumination light on the pupil of the projection optical system is assumed to be substantially rotationally symmetric with respect to the center of the pupil when the mask is absent, annular illumination or It is possible to expose a pattern having a resolution better than that obtained by the conventional method without using the direct illumination. In this case, in particular, even when the directivity σ of the illumination is large, the relative reduction in the contrast in the high frequency region of the resolution pattern, which has occurred conventionally, does not occur, and exposure can be performed with high resolution.

In the case of a negative resist in which a desired pattern portion serves as a light-shielding portion, resolution of the outer light-transmitting portion adjacent to the light-shielding portion and this light-shielding portion are required, so that the adjacent light-transmitting portion has a polarization characteristic, for example. If a conductive fine pattern is provided, high resolution similar to that of a positive resist can be realized. At this time, the width of the portion which gives the polarization characteristic around this may be equal to or more than the resolution limit of the projection lens in consideration of light wraparound (diffraction). The outer side of this fine pattern is made a transmission part through which 100% light passes, and if the exposure amount of the part that gives the polarization characteristics exposes the negative resist and the resist remains after development, 100% light transmission will occur. The resist remains on the portions, and a desired resist pattern can be formed with high resolution.

A smooth polarization characteristic can be obtained by using a fine pattern in a 45 ° direction or a fine pattern on an arc at the tip of the pattern where the pattern bends at a right angle as a pattern having a polarization characteristic, and a higher resolution can be obtained. To be

By using the super-resolution method of the present invention together with the phase shifter, one is in the case of a pattern tip portion or the outermost peripheral pattern, or two repeating pattern groups are oriented in the xy directions. Gives sufficient resolution when the patterns touch each other. In the former case, the auxiliary phase π pattern is provided in the periphery to suppress the spread of the skirt of the pattern, and in the latter case, the intensity level between the contacting pattern groups can be suppressed low.

[0034]

FIG. 1 shows an embodiment of the present invention.

FIG. 1A shows a projection exposure apparatus of the present invention, and 1 is an illumination light. A method of forming the illumination light will be described in detail later, but B ₀ , B ₉₀ , B ₁₈₀ , and B which are partial lights of the illumination light.
_Reference numerals ₂₇₀ respectively have the linearly polarized light shown in the drawing, and when the mask 2 is not provided, they irradiate on a ring-shaped band like the illumination light 11 on the pupil 3 of the reduction lens 31 which is the projection optical system. The irradiation lights B ₀ ′, B ₉₀ ′, B ₁₈₀ ′ and B ₂₇₀ ′ are linearly polarized on the pupil as shown in the figure.

On the mask 2 of the present invention, patterns l ₁ , l ₂ , l ₃ , l ₄ oriented in, for example, the x direction and the y direction are drawn, and the polarization characteristics corresponding to the direction in which these patterns are oriented are drawn. , These patterns are irradiated and given to the transmitted light.

That is, focusing on, for example, l ₂ shown in FIG. 1B, the edge C ₁ C ₂ of the pattern is oriented in the y direction as shown in FIG. %, And linearly polarized light in the x direction is blocked. Similarly, C ₁ C ₂
Since the portion surrounded by C ₃ C ₄ faces the x direction, almost 100% of the linearly polarized light in the x direction is transmitted and the linearly polarized light in the y direction is blocked. By doing so, the portion surrounded by C ₁ C ₂ C ₃ C ₄ which is the pattern portion in the x direction is effectively B
Illumination light having a directivity of ₉₀ and B ₂₇₀ is transmitted, and the diffracted light from this pattern spreads over a wide range on the pupil (a range corresponding to the pupil diameter), which contributes to image formation and The resolution pattern can be exposed on the exposure chip area 4 on the wafer 41.

This means that the C ₁ C ₂ pattern end face and y
Similarly, with respect to the pattern oriented in the direction, the y-direction polarized component is transmitted and the x-direction is shielded to expose the pattern in the y-direction with high resolution. In this way, the pattern-dependent polarization characteristics are given to the mask, the polarization is properly used, and only the directional illumination light, which is convenient for high resolution of each pattern, is effectively transmitted, and high-resolution exposure is realized.

FIG. 2 shows an embodiment of a pattern-dependent polarization mask that imparts to the pattern-transmitted light the polarization characteristics according to the direction of the pattern shown in FIG. In this figure,
Only the pattern of l _{2 in} (b) is shown enlarged. Figure 1
The positions corresponding to C ₁ , C ₂ , C ₃ and C ₄ in (b) are indicated by the same symbols. The shaded portion in the figure is a portion that has high electrical conductivity and blocks light. In the pattern portion C ₁ C ₂ C ₃ C ₄ facing the x direction, the pattern of the thin light shielding portion facing the x direction is arranged, and the pattern of the thin light shielding portion in the y direction is formed at the end of C ₁ C ₂ facing the y direction. Are arranged. Therefore, the polarization characteristics as described above are imparted to the transmitted light.

As is well known, when the width of the opening of the slit pattern becomes about ½ of the wavelength, only polarized light in the direction of this slit passes, and polarized light in the direction orthogonal thereto. Is shielded from light. Further, since the line width of the light transmitting portion is thin beyond the resolution limit of the projection optical system, the fine structure in the pattern of l ₂ does not form an image.

FIG. 3A shows an embodiment of a pattern-dependent polarization mask which imparts a polarization characteristic according to the direction of the pattern shown in FIG. 1 to the pattern transmitted light. As in FIG. 2, only the pattern of l ₂ in FIG. 1B is shown in an enlarged manner, and the positions corresponding to C ₁ , C ₂ , C ₃ and C ₄ in FIG. 1B are indicated by the same symbols. ing.

3 (b) and 3 (c) show AA 'in FIG. 3 (a).
It shows a cross section when cut by. Reference numeral 202 denotes a light-shielding portion, and 203 denotes a glass which is a base of this mask. The portion that transmits light has slopes 201A and 201B, and this portion is provided with a coating known per se for use in a polarization beam splitter. A transparent glass material is applied on the coating so as to have a flat surface.

With such a structure, as is well known by the action of the polarization beam splitter, as shown in FIG.
As shown in, the light incident on this transmission part is P-polarized light 1P.
Only S-polarized light 1S is not transmitted. As a result, only polarized light orthogonal to the direction of the pattern passes, and C ₁
At the end of C ₂ , polarized light orthogonal to the direction of the pattern edge at this end passes. In the case of the present embodiment, the polarization on the pupil of the projection optical system is as shown in FIG.
A polarized light orthogonal to the polarized light shown in (1) is given to the illumination light in advance.

Using the masks of FIGS. 2 and 3, the polarization state on the pupil of the projection optical system as shown in FIG. 1, FIG. 5 or FIG. Illumination light whose state is substantially rotationally symmetrical with respect to the center of the pupil is emitted. For example, the wavelength is the i-line of a mercury lamp (λ = 365
nm), the numerical aperture NA of the projection optical system is 0.57, and the width of the exposure pattern is 0.25 μm. Further, the reduction ratio of this projection optical system is ⅕. Since the pattern size on the mask is five times as large as the exposure pattern, for example, as shown in FIG.
The width of the slit without pattern is 0.18 to 0.2 μm
It is about the same, which is half the wavelength as described above. In this way, polarized light equal to the direction of the pattern is transmitted from the mask, and as described above with reference to FIG. 9, a higher resolution than that shown in FIGS. .

An embodiment of the present invention will be described with reference to FIG. FIG. 10A shows a sectional view of the surface of the mask.
For example, l ₂ and l ₃ are the pattern l ₂ of the mask of FIG.
And l ₃ . In this embodiment, the light-shielding portion 202 ′ between the patterns does not completely block light but slightly transmits light. In addition, the slopes 201A ′ and 201B ′ that function as the polarization beam splitter described in FIG.
However, as shown in the figure, the light-shielding portion 202 'that slightly allows light to pass therethrough.
Also exists. By doing so, the light transmitted through this portion of the mask passes only the P-polarized light in both the transmissive portion and the light-shielding portion, and the S-polarized light is completely shielded. Ie the direction of the pattern
Only the polarized light in the direction orthogonal to (direction perpendicular to the paper surface) is transmitted.

The pattern-transmitted light of such polarization is shown in FIG.
The amplitude transmittance is as shown in 0 (b). That is, the light transmitting portion of the pattern is 1 and the light shielding portion is -0.22.
(That is, the amplitude transmissivity is 22% and the phase is shifted by 180 ° with respect to the transmissive part). When such a mask is irradiated with illumination light having directivity and polarization characteristics as shown in FIG. 11A, as described above, only polarized light perpendicular to the edge of the pattern is transmitted and the center of the pupil of the lens is transmitted. The diffracted light spreads in a wide range passing through, the high-frequency component of the pattern passes through the pupil, and a pattern with high resolution can be exposed as shown in FIG.

As will be described in detail later with reference to FIG. 14, as shown in FIG. 11 (b), the illumination light is in a non-polarized state, and the light polarized radially with respect to the optical axis of the lens is passed through the pupil of the lens. The object of the present invention can be achieved by disposing the polarizer (analyzer) 33.

FIG. 13 shows an embodiment of the present invention. FIG.
FIG. 13A is a cross-sectional view of the mask of the present invention, showing the complex amplitude transmittance of the transmitted light of the illumination light incident from below in FIG.
It is shown in FIG. FIG. 13C is a plan view of this mask, in which the shaded portions are light shielding portions and the non-shaded portions are light transmitting portions. In FIG. 13A, l ₂ is a portion of the pattern to be exposed, in which at least one conductive light-shielding portion 2011 ″ described in FIG. 2 exists. This number is the width of the transmitting portion 2012 ″. Is about 1/2 of the wavelength.

In this embodiment, in the pattern 0, that is, the portion which is not exposed, unlike the embodiment shown in FIG.
020 ″ is provided between the light shields 2021 ″.
Further, a phase shifter 202 ″ of approximately 180 ° is provided in the 0 part of this pattern. As a result, the complex amplitude of the light immediately after passing through this mask is as shown in FIG. 13 (b). Also, the 1's and 0's of the pattern 201 "and 2
The intensity component ratio of the 02 ”transmitted light passing through the pupil of the lens is
Leave it at 1: 0.22 ² .

By doing so, polarized light in the edge direction of the pattern is simultaneously transmitted, so that, for example, if the mask is irradiated with illumination light in a non-polarized state as shown in FIG. 14, the direction of the edge of the pattern on the mask is changed. Only polarized light that is directed through passes through the mask. Therefore, as shown in FIG. 14, a polarizing element 33 whose polarization state is substantially rotationally symmetric with respect to the center of the pupil is arranged on the pupil of the lens. In this way, the light that passes through the pattern becomes polarized light that is oriented in the edge direction of the pattern, and among these pattern-transmitted light, the light that is diffracted in the direction that passes through the center of the pupil passes through the polarization element 33. (Strictly speaking, as the position where the light diffracted by the edge of the pattern spreads on the pupil becomes farther from the center of the pupil, the ratio of passing through the polarizing element 33 becomes smaller).

As a result, similar to that shown in the embodiments of FIGS. 10 and 11, the resolution as shown in FIG. 12 is obtained, and it becomes possible to expose a high resolution pattern with excellent pattern separation. . As shown in FIG. 14, the polarization element 33 is an element element P ₀ that transmits polarized light in a certain direction,
The object of the present invention can be achieved by arranging a plurality of P ₁ , P ₂ ... P _n so that the polarization state is substantially rotationally symmetric with respect to the pupil center as shown in the figure.

In the embodiments shown in FIGS. 10 and 11 and FIGS. 13 and 14, the pattern 0 (light-shielding portion) is 1.
Although the complex amplitude transmittance is 22% with respect to the (transmissive portion), the value is not necessarily limited to this value in order to achieve the object of the present invention, and noise due to light leakage of the light shielding portion is shown. (Noise due to leakage of light generated in the 0 part outside the repeating pattern shown in FIG. 12) is 0 between the repeating patterns.
The complex amplitude transmittance above the level of the light-shielding part is about 3
It should be 0% or less.

Further, in the embodiments of FIGS. 10 and 13, the transmittance of the light-shielding portion other than the periphery of the portion which transmits almost 100% of light is not the above-mentioned 22% or 30% but is completely shielded, that is, 0. If it is set to%, some fogging of the resist due to leakage of light other than the pattern portion is eliminated, and a more reliable integrated circuit can be manufactured.

FIG. 5 is a diagram showing an embodiment of a ring-zone / rotationally symmetric polarized illumination means for realizing illumination light in which the polarization state on the pupil of the projection optical system shown in the embodiment of FIG. 5 is rotationally symmetric with respect to the center of the pupil. 15
~ It demonstrates using FIG. An overall view of the annular / rotationally symmetric polarized illumination means has the structure shown in FIG. The light emitted from the mercury lamp uses a well-known ellipsoidal mirror (see FIG. 2).
(Refer to 0), the light is efficiently incident on this means. The incident light enters the polarized light emitting means 100.

The polarized light emitting means 100 has a structure as shown in FIGS. The perspective view of FIG.
The upper left is an overall view of the polarized light emitting means 100, and the lower right is 1
Reference numeral 01 and 102 at the lower right of the figure denote the polarized light generating and emitting means 100 divided into two parts. Reference numeral 101 denotes a polarization beam splitter (PBS) composed of 1011, 1012, and 1013, which causes incident light from the mercury lamp to travel in the z direction, as shown in a side view in FIG.
Light incident on the BS surface is transmitted by P-polarized light and reflected by S-polarized light.

As a result, as shown in FIG. 15, the light traveling in the z direction passing through 101 is linearly polarized light polarized in the y direction, and the upper half of the light reflected by 101 is upward along the y axis. Facing, the lower half also points downwards along the y-axis.
Moreover, the polarized light becomes linearly polarized light in the x direction. The light transmitted through 101 is incident on the prism 102, and is totally reflected by the slope, and becomes light in the ± x direction.

The light traveling in the ± x direction is linearly polarized light in the y direction. That is, the polarized light generating and emitting means 100 causes the light incident on the polarized light emitting and emitting means 100 to have a radial (± x, ± x, as shown in FIGS.
(+/− y direction), and the polarization of each light is made rotationally symmetrical with respect to the optical axis of the light incident on 100.
The light radiated in four directions by the polarized light generating and emitting means 100 is transmitted through the cylindrical lenses 1031, 1032, 1033 and 1034 as shown in FIG.
5 fan-shaped divergent light rays 1051, 1052, 105
3 and 1054.

The origin of divergence of these divergent lights is almost close to the optical axis. By doing so, the light reflected by the quadric surface mirror 105 is emitted from the screen 100 as shown in FIG. 17, for example.
When 0 is set, a ring-shaped and rotationally symmetrical linear polarization characteristic is present on this screen, and the illumination shown in FIG. 5 can be realized.

In order to realize the radial linearly polarized light shown in FIG. 11, for example, the linearly polarized light radially emitted from the polarization generating / radiating means 100 is used by using a half-wavelength version.
The polarization direction may be rotated by 90 °. 15 to 17
Although the polarized light emitting and radiating means 100 of the illumination system described in (4) separates and diverges light in four directions, it may also separate and diverge in six or eight directions.

FIG. 18 is a diagram showing an embodiment of the exposure method of the present invention. By making the shape of the reflecting surface of the PBS conical, it is possible to illuminate continuously and uniformly. 18 (a) is a perspective view and 18 (b) is a sectional view.

The conical surface of the cone 101 'is a polarization beam splitter. The randomly polarized exposure light entering here passes through the axis of the cone, that is, the screen 1 of FIG.
As can be seen from the spread and polarization state of the light 1102 above 000, the linearly polarized light polarized in the radial direction from the axis is the PBS.
Through.

On the other hand, polarized light orthogonal to this is reflected, and is totally reflected by the conical prism 102 '. Immediately after passing through the conical prism 102 ′, this light is orthogonal to the light of 1102 as shown in FIG. 18B, but by passing through the ½ wavelength plate 131, the polarization direction Is rotated by 90 ° and becomes a radially polarized light as indicated by 1101. This one
In the / 2 wave plate, the axis of the crystal plate forming the wave plate is shown in FIG.
1311, 1312, 1313 ... are provided so as to rotate by 45 ° each. In this way, almost any part of the illumination light becomes linearly polarized light.

In the embodiment of FIG. 18, the incoherent illumination has almost no directivity of the illumination light. Even if such incoherent illumination is used, the directional light that deteriorates the resolution is cut by using the mask of FIG. 3 of the present invention, and a high-resolution pattern that cannot be obtained by the conventional exposure method. Can now be exposed.

FIG. 19 shows an embodiment of the present invention. Depending on the pattern to be exposed, it is not always necessary to use annular illumination, but rather normal illumination may be preferable. FIG. 19 shows an illumination system of a pattern exposure apparatus which is effective in such a case. Eight halves arranged radially in FIG.
The wave plate is arranged on the rotating disk 13. As shown in FIG. 19, six types of the rotating discs 13 are arranged on the circumference of the disc. By rotating the discs 13, various polarization states are substantially rotationally symmetric with respect to the pupil center. It becomes possible to realize normal illumination and ring illumination having a certain polarization characteristic.

As shown in FIG. 19, 131, 132, 1
By selecting 33, ... 136, FIG. 19 (a) (b) (c) ...
The normal illumination having the polarized light of (g) and the annular illumination are possible.

FIG. 20 shows an embodiment of the exposure apparatus of the present invention. The light emitted from the mercury lamp 150 is an ellipsoidal mirror 151.
Reflected by the mirror 152, reflected by the mirror 152, passed through the lens 153, and then incident on the fiber bundle 154. The exit end of the fiber is located in the fiber exit end position control mechanism 155, where a plurality of finely separated small fiber bundles are distributed at desired intervals to obtain a desired illumination directivity.

Light having a desired spread in this way passes through the polarized light emitting means 100 and the quadric curved surface mirror 1052 described with reference to FIGS.
6 illuminates the reticle 21. Reticle 21
2 is the pattern-dependent polarization mask shown in FIG. 2 and the like, the pattern projected through the reticle and projected onto the wafer by the reduction lens has a high resolution.

FIG. 21 shows an exposure apparatus using the excimer laser of the present invention. The laser light emitted from the laser light source is
It is incident on the fiber bundle 157. This fiber bundle 15
7 is divided into many small fiber bundles on the way. Each small fiber bundle has a difference in length that is equal to or longer than the coherence length of laser light. By doing so, the laser light emitted from the fiber emission end realizes uniform illumination without interference.

The light emitted from the fiber end is incident on the lot lens with desired directivity and polarization characteristics by the polarization generating / radiating means 100 'and the rotating disk 13 described with reference to FIGS. The lot lens is effective in uniformly illuminating the reticle. The illumination light that has passed through the lot lens passes through the condenser lens 156 and illuminates the reticle 21, which is the pattern-dependent polarization mask of the present invention, and the reduction lens 31 exposes a high-resolution pattern on the wafer 41. If a KrF excimer laser is used, it is possible to expose a pattern of 0.17 μm, which is a design dimension of 1G DRAM. By further shortening the wavelength, it becomes possible to expose a 0.1 μm pattern.

FIG. 22 shows an embodiment of the present invention using an excimer laser. The light emitted from the excimer laser 150 ′ has an optical path length different from each other by several times the coherence length of the laser.
Book prisms 1651, 1652, 1653 and 1654
Through the optical path length adjusting means 165. The four beams that have lost their coherence to each other are the pyramidal quadrangular pyramid mirror 1
At 600, it reflects in four directions.

Since the emitted light of the excimer laser 150 'is linearly polarized light in the x direction, the light reflected by the quadrangular pyramid mirror is y light.
Directional is polarized light in the x direction. However, the light traveling in the x direction is desired to be polarized in the y direction, but is polarized in the z direction. Then, a half-wave plate 1603 (the half-wave plate of 163 is not shown) is passed through the incoherent light diverging means 161 and 163 on which the light in the x direction enters.
Change to polarized light in the y direction.

The incoherent light diverging means 161 will be described. The other three incoherent light diverging means are the same as 161 although not shown. The light incident on the incoherent light diverging means 161 first passes through the optical path length adjusting means 1601. Here, the incident beam is divided into a plurality of portions, and the optical path length difference between the respective portions is set to a coherence length or more. At this stage, the parallel light is converted into the concave cylindrical lens 1
At 602, the light is divergent. The divergence source of this divergent light is approximately on the laser optical axis in the figure. The light diverged in four directions by the four incoherent light diverging means is reflected and condensed by the quadric surface mirror 105, enters the concave lens 158 ', and enters the lot lens 158 in a state where the principal rays are substantially parallel. To do.
The configuration after the lot lens is the same as that of the embodiment shown in FIG.

FIG. 23 shows an example of a reticle pattern when a hole pattern is exposed using a negative resist. FIG. 23A is an example of exposure of a hole pattern. In the case of a negative type resist, the resist in the non-exposed area is removed after development, but in the exposed area, the area exposed by a certain exposure amount or more remains, so that 2B corresponding to the hole area becomes the non-exposed area and the surrounding area. Pattern 2A1, 2A2, 2A3, 2
A4 has a pattern having polarization characteristics. The outside 2A0 of the portion having this polarization characteristic is a light transmitting portion having a transmittance close to 100%. When the polarized ring zone illumination is performed in this way, the light incident from the direction orthogonal to the pattern edge of 2B is transmitted through the polarization characteristic portions 2A1 to 2A4 to increase the resolution of the pattern edge. This polarization characteristic section 2A1
The intensity of the light transmitted through 2A4 is smaller than that of the 2A0 part because it does not pass through the polarized light at right angles to this polarized light. However, as described above, if the weakened intensity is equal to or more than the certain exposure amount, only the 2B part is emitted. It is formed in the negative resist as a hole pattern.

FIG. 23B shows a case where the L & S pattern is exposed with a negative resist. The line portion 2D is a light-shielding portion as in the embodiment (a), and a line-to-line pattern having a polarization characteristic is provided. Further, patterns 2C1 to 2C3 having polarization characteristics similar to the hole pattern are arranged around the outermost circumference of the pattern. If the exposure is performed so that the light quantity of the transmission term from the portion having the polarization characteristic is equal to or more than the above-mentioned constant exposure quantity, the negative resist can be exposed to the L & S pattern with high resolution.

FIG. 24 shows an example in which a corner portion and a pattern edge portion of a pattern are exposed with high resolution by using a positive type resist. Even if an attempt is made to have a polarization characteristic by drawing a fine pattern of half the wavelength or less at the corner portion or the pattern edge portion, sufficient polarization characteristic may not be obtained if the fine pattern is bent at a right angle. In such a case,
As shown in (a), (b) and (c) of 4, it is possible to obtain better polarization characteristics by adding a pattern in the direction of 45 ° or an arc-shaped pattern without making the pattern bent at right angles. .

FIG. 25 shows an embodiment in which the resolution performance at the tip of the pattern is further improved by using a phase shifter in combination with the super-resolution method of the present invention. As shown in FIG. 25 (a), when the line pattern part l _L that is long in the horizontal direction and the line pattern part l _{V that} is long in the vertical direction are in contact with each other at the BB part, the tip of l _L facing the BB part and the l _V The resolution of the leftmost pattern may not be sufficient. In such a case, the phases of the transmitted light are made to differ from each other by π on the right side and the left side with the BB portion as a boundary.
FIG. 25B is a sectional view of this reticle. The left side of the BB part is a normal reticle drawing surface, but the right side is the shifter 2.
02 ”is attached, and the transmitted light is phase-shifted by π. In FIG. 25 (c), this shifter is drawn on a substrate different from the glass substrate of the reticle drawn with Cr, and this is
They are attached so that the positions corresponding to each other coincide with each other. Since the pattern of the phase shifter is a rougher pattern than a normal phase shift reticle, the bonding of these two glass substrates can be easily realized, and the resolution of the pattern edge and the periphery of the pattern becomes high. FIG. 26 shows the intensity of the BB portion when the phase shifter is not used by a dotted line,
The solid line shows the intensity of the BB portion when the phase shifter is used.
The dotted line pattern has a higher resolution than the conventional one, but the pattern separation is further improved by using the phase shifter.

FIG. 27 shows an embodiment in which the super-resolution method of the present invention is applied to an isolated pattern to further improve the resolution. Figure 2
As shown in FIG. 7 (a), the l'part is a part having the polarization characteristics described above. An auxiliary phase shifter pattern l _cp is provided around this line pattern. FIG. 27
As shown in (b), the auxiliary phase shifter pattern l _cp has a phase difference of π with respect to the transmitted light of the line pattern portion l ′ by passing through the transparent thin film 202 ″ ″. By doing so, as shown in FIG. 27 (c), a resolution pattern shown by a higher solid line is obtained as compared with the dotted line in the case where there is no phase shifter having a higher resolution than that obtained by the conventional exposure method.

The oblique incident angle (illumination directivity σ) of the polarized ring zone illumination optimum for the line width of the pattern to be resolved varies depending on the required depth of focus. The relationship obtained by simulation is shown in FIGS. 28 and 29. Now, assuming that the NA of the reduction exposure lens is 0.57 and the exposure wavelength is i
If a line (365 nm) is taken, for a 0.2 μm pattern, as shown in FIG. 28, when σ is 0.5 to 0.7, sufficient resolution cannot be obtained even at the best focus position (DF = 0 μm). On the other hand, by setting σ to 0.75 to 0.95, it is possible to sufficiently resolve up to a defocus of 0.75 μm as shown in FIG. However, when a 0.4 μm pattern is exposed with the same exposure wavelength using the same lens, σ is 0.75 to 0.75 as shown in FIG.
On the contrary, when the value is set to 0.95, the resolution is deteriorated due to the defocus of 0.5 μm, whereas when the value of σ is 0.5 to 0.7, the resolution becomes 0.
It is well resolved up to 75 μm. As described above, a means for selecting the optimum directivity σ of the annular illumination according to the width of the pattern to be exposed is provided, and the optimum σ is set by this means, so that a good pattern can be formed in a wide pattern width range. It becomes possible to expose.

Although all of the mask embodiments described above are transmission type masks, the object of the present invention can be achieved by using reflection type masks. Further, in the above-mentioned embodiment, as the pattern-dependent polarization mask, the one having the minute slit structure and the minute polarizing prism structure is used, but an anisotropic medium or a dichroic object is optically transmitted depending on the direction of the pattern. The object of the present invention can also be achieved by arranging the parts.

The exposure method of the present invention makes it possible to expose a circuit pattern that cannot be resolved by the conventional annular illumination. As a result, when the line width w of the repeating pattern, the pitch p of the repeating pattern, the exposure wavelength λ, and the numerical aperture of the projection optical system are NA, a semiconductor integrated circuit including a circuit pattern satisfying the following expression is manufactured. But it has become possible.

0.25λ / NA <w <0.5λ / NA 0.5λ / NA <p <1.0λ / NA

[0082]

By using the pattern exposure method of the present invention, it becomes possible to expose a pattern having a resolution far superior to that of the conventional resolution pattern by using the projection optical system of the exposure apparatus used conventionally as it is. The semiconductor integrated circuit technology can be significantly improved by improving the performance of the semiconductor integrated circuit, the production yield of the semiconductor integrated circuit can be improved, and the significant economic effect can be achieved by reducing the capital investment for manufacturing the semiconductor integrated circuit.

[Brief description of drawings]

FIG. 1A is a perspective view of an illumination system of a pattern exposure apparatus according to the present invention and FIG. 1B is a plan view of a mask used for the illumination system.

FIG. 2 is a plan view of a mask (or reticle) according to the present invention.

3A is a plan view of a mask (or reticle) according to the present invention and FIG. 3B is a sectional view taken along line AA ′ of FIG.

FIG. 4 is a perspective view of an illumination system of a conventional exposure apparatus.

FIG. 5 is a perspective view of an illumination system of the pattern exposure apparatus according to the present invention (a) and a deflection state of the illumination (b), and a light transmittance (c) of a mask pattern.

FIG. 6 is a diagram showing a state of resolution of a pattern obtained by conventional annular illumination.

FIG. 7 is a diagram showing a state of resolution of a pattern in the xy directions with respect to a conventional oblique incident exposure from the direction of 45 degrees to the xy axes.

FIG. 8 is a diagram showing a state of resolution of a pattern having an inclination of 45 ° with respect to the xy direction with respect to oblique incidence exposure from the direction of 45 degrees on the xy axis.

FIG. 9 is a diagram showing a resolution state of a resolution pattern obtained by an exposure method according to the present invention.

FIG. 10 is a plan view (a) of a mask (or reticle) according to the present invention and a view (b) showing a complex amplitude transmittance of the mask.

FIG. 11A is a perspective view of an illumination system of the exposure apparatus according to the present invention and FIG. 11B is a perspective view showing a deflected state.

FIG. 12 is a diagram showing a resolution situation of a resolution pattern obtained by using FIGS.

13A is a sectional view of a mask according to the present invention, FIG. 13B is a diagram showing a complex amplitude transmittance of the mask, and FIG. 13C is a plan view of the mask.

FIG. 14 is a perspective view of an illumination system of an exposure apparatus using the mask of FIG. 13 according to the present invention.

FIG. 15 is a perspective view of an illumination system used in the exposure apparatus of the present invention.

FIG. 16 is a perspective view of an illumination system used in the exposure apparatus of the present invention.

FIG. 17 is a perspective view of an illumination system used in the exposure apparatus of the present invention.

FIG. 18 is a perspective view of an illumination system capable of switching between normal illumination and annular illumination of the exposure apparatus according to the present invention.

19 is a perspective view of means for switching the illumination system of the exposure apparatus of FIG.

FIG. 20 is a perspective view of an exposure apparatus according to the present invention.

FIG. 21 is a perspective view of an exposure apparatus that uses an excimer laser as a light source according to the present invention.

FIG. 22 is a perspective view of an exposure apparatus using an excimer laser as a light source according to the present invention.

FIG. 23 is a plan view of a mask pattern using a negative resist according to the present invention.

FIG. 24 is a plan view of a fine pattern of a pattern corner portion and a pattern tip portion according to the present invention.

FIG. 25 is a plan view and a side view (a) of a mask of a separation method using a phase shifter for adjacent xy patterns according to the present invention.
(B), and the side view of a mask separation type (c).

FIG. 26 is a comparison of a pattern (solid line) obtained by the method of FIG. 25 with a conventional one (broken line).

FIG. 27 is a plan view (a), a side view (b) of a method using an auxiliary pattern according to the present invention, and an effect of this method (solid line) compared with a conventional method (broken line).

FIG. 28: Effect of illumination directivity on resolution when a 0.2 μm pattern is resolved by the method of the present invention

FIG. 29 shows the influence of illumination directivity on resolution when a 0.4 μm pattern is resolved by the method of the present invention.

[Explanation of symbols]

 1 ... exposure light, 11 ... exposure light on pupil, 21 ... mask or reticle, 2 ... circuit pattern on reticle, 31 ... projection optical system, 3 ... pupil of projection optical system, 41 ... wafer, 4 ... on wafer Exposure chip.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location 7352-4M H01L 21/30 515 B 7352-4M 515 Z (72) Inventor Minoru Yoshida Yokohama City, Kanagawa Prefecture Hitachi Engineering Co., Ltd., 292 Yoshida-cho, Totsuka-ku (72) Inventor Masahiro Watanabe 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Pref., Hitachi, Ltd.

Claims (47)

[Claims] 1. A mask or reticle on which a desired original image pattern is drawn is irradiated with light from an exposure illumination light source with desired directivity, and transmitted light or reflected light of the mask is projected through a projection optical system. In a pattern exposure method of projecting onto an exposure object and exposing an image from the original image pattern, a pattern-dependent polarization mask that imparts polarization characteristics according to the direction of the pattern on the mask to the illumination light that has passed through the pattern. A pattern exposure method comprising: 2. The pattern exposure method according to claim 1, wherein the directivity of the illumination light is annular illumination or oblique illumination. 3. The pattern according to claim 1, wherein the illumination on the pupil of the projection optical system has a polarization state substantially rotationally symmetric with respect to the center of the pupil when the mask is not provided. Exposure method. 4. The pattern exposure method according to claim 1, wherein a polarization element or an analysis element whose polarization state is substantially rotationally symmetrical with respect to the pupil center is arranged near the pupil of the projection optical system. 5. The mask according to claim 1, wherein the tangential direction of the edge of the pattern on the mask and the polarization direction of the light of the illumination light transmitted or reflected through the pattern are substantially parallel to each other. The pattern exposure method described. 6. A pattern on a mask is composed of a portion A which transmits or reflects illumination light and a portion B which transmits or reflects a little but substantially shields or hardly reflects, and the light transmitted through the portions A and B has a phase relative to each other. The pattern exposure method according to claim 2, wherein the masks different by 180 ° are used. 7. The amplitude transmittance or the amplitude reflectance of the substantially light-shielding portion B is 30% or less with respect to the amplitude transmittance or the amplitude reflectance of the transmitting portion A. Pattern exposure method. 8. The pattern exposure method according to claim 7, wherein the amplitude transmittance or the amplitude reflectance is approximately 22%. 9. The directivity of the annular illumination or the directional illumination is such that one of ± 1st order diffracted light from a minimum pattern on a mask illuminated by this irradiation light is a pupil of the projection optical system. The pattern exposure method according to claim 2, wherein the other side does not pass through the pupil. 10. The pattern exposure method according to claim 2, wherein the directivity of the annular illumination or the oblique illumination is variable according to the line width of the pattern on the mask. 11. The illumination light is a normal illumination (not an annular illumination or an oblique illumination), its directivity σ is 0.5 or more, and the illumination light has its polarization state at the center of the pupil when the mask is not provided. The pattern exposure method according to claim 1, wherein the pattern exposure method is substantially rotationally symmetric with respect to. 12. The object to be exposed is a negative type photosensitive material, a desired pattern is a light-shielding portion on a mask, and a pattern having a polarization characteristic is drawn around the light-shielding portion. The pattern exposure method according to claim 1. 13. The pattern having a polarization characteristic drawn around the light-shielding portion has a width which is substantially equal to a pattern width resolvable by the projection optical system. Pattern exposure method. 14. The pattern exposure method according to claim 1, wherein the mask having the polarization characteristic is provided with a phase shifter. 15. The pattern exposure method according to claim 14, wherein the phase shifter is configured such that a phase difference between patterns or between pattern groups is π. 16. The pattern exposure method according to claim 14, wherein the phase shifter is provided in the periphery of an isolated pattern or a group of patterns with such a fineness as not to be resolved by the projection optical system. 17. An exposure illumination light source, a mask or reticle on which a desired original image pattern is drawn, an illumination optical system for irradiating the mask with the light emitted from the light source with a desired directivity, and a transmission of the mask. In a pattern exposure apparatus consisting of a projection optical system for projecting light or reflected light onto an object to be exposed, if the mask is not provided, the polarization state of the illumination light on the pupil of the projection optical system with respect to the center of the pupil. A pattern exposure apparatus characterized by comprising a polarizing means which is approximately rotationally symmetrical. 18. The pattern exposure apparatus according to claim 17, wherein the illumination optical system is provided with a modified illumination means for realizing annular illumination or oblique illumination. 19. The pattern exposure apparatus according to claim 17, wherein the polarization means is effectively included in the illumination optical system. 20. The pattern exposure apparatus according to claim 17, wherein the polarizing means is included in the projection optical system. 21. The pattern exposure apparatus according to claim 17, wherein the exposure illumination light source is a mercury lamp. 22. The pattern exposure apparatus according to claim 17, wherein the illumination light source is an excimer laser. 23. The modified illuminating means for realizing the annular illumination or the oblique illumination of the illumination optical system is provided with a means for varying the directivity of the annular illumination.
8. The pattern exposure apparatus according to item 8. 24. The means for varying the directivity of the illumination controls the means for varying the directivity so that the directivity according to the line width of the exposure pattern is optimized. The pattern exposure apparatus described. 25. The pattern exposure apparatus according to claim 23, wherein the means for varying the directivity of the annular illumination uses a flexible optical fiber. 26. The pattern exposure apparatus according to claim 23 or 24, wherein the means for varying the directivity of the annular illumination is capable of realizing non-annular normal illumination. 27. A mask that imparts pattern-dependent polarization characteristics that imparts polarization characteristics depending on the direction of the pattern on the mask to illumination light that transmits or reflects the pattern. 28. The mask according to claim 27, wherein a tangential direction of an edge of the pattern on the mask and a polarization direction of light of the illumination light transmitted through or reflected by the pattern are substantially parallel to each other. 29. The mask according to claim 27, wherein a tangential direction of an edge of a pattern on the mask and a polarization direction of light of the illumination light transmitted through or reflected by the pattern are substantially orthogonal to each other. 30. The pattern on the mask comprises a portion A which transmits or reflects illumination light and a portion B which slightly transmits or reflects but does not substantially shield or reflects the illumination light, and the light transmitted through the portions A and B are in phase with each other. Is 180 °
28. The mask according to claim 27, which is different. 31. The amplitude transmittance or the amplitude reflectance of the substantially light-shielding portion B is effectively 30% or less of the amplitude transmittance or the amplitude reflectance of the transmitting portion A. The mask according to item 30. 32. The amplitude transmittance or the amplitude reflectance of the substantially light-shielding portion B is substantially 22% of the amplitude transmittance or the amplitude reflectance of the transparent portion A. 31. Mask. 33. The mask according to claim 30, wherein the substantially light-shielding portion B exists only near the light-transmitting portion A. 34. The mask according to claim 27, wherein the means for imparting the polarization property comprises an anisotropic medium, a minute polarization prism structure, a dichroic object, or a minute slit structure. 35. The minute polarization prism structure has a surface inclined at least at a pattern transmission part, and has a film formed by multilayer vapor deposition on the inclined surface, and covers a transmission object so as to fill the inclined surface. 28. The mask according to claim 27, which has a structure having a flat surface. 36. The mask according to claim 27, wherein the minute slit structure has a structure in which a fine single line or a plurality of fine lines are drawn along the line of the edge of the pattern transmitting portion. 37. The width of the opening of the minute slit is about 1/2 or less of the exposure wavelength λ.
The listed mask. 38. The mask according to claim 36, wherein the thin line is conductive. 39. The mask according to claim 27, wherein a desired pattern is a light-shielding portion on the mask, and a pattern having a polarization characteristic is drawn around the light-shielding portion. 40. The pattern having polarization characteristics drawn around the light-shielding portion has a width which is substantially equal to a pattern width resolvable by the projection optical system. mask. 41. The mask according to claim 27, wherein the mask having the polarization characteristic is provided with a phase shifter. 42. The mask according to claim 41, wherein the phase shifter has a phase difference of π between patterns or pattern groups. 43. The mask according to claim 41, wherein the phase shifter is provided in the periphery of an isolated pattern or pattern group with a fineness not to be resolved by the projection optical system. 44. A mask or reticle on which a desired original pattern is drawn is irradiated with light from an exposure illumination light source with desired directivity, and transmitted light or reflected light of the mask is projected through a projection optical system. In a semiconductor integrated circuit formed by a pattern exposure method of projecting onto an exposure object and exposing an image from the original image pattern, the directivity of the illumination light is an annular illumination or a directional illumination, and the pattern on the mask A semiconductor integrated circuit including a fine pattern in at least two directions, which is formed by a pattern exposure method using a pattern-dependent polarization mask that imparts polarization characteristics according to the direction in which the illumination light is transmitted through the pattern. 45. The two-direction fine pattern includes at least a repeating pattern, and the line width w or the repeating pitch p of the repeating pattern is 0..0 when the exposure wavelength is λ and the numerical aperture of the projection optical system is NA. 25λ / NA <w <0.5
The semiconductor integrated circuit according to claim 44, wherein λ / NA or 0.5λ / NA <p <1.0λ / NA is satisfied. 46. A pattern including a pattern that cannot be exposed by the phase shifter method and a repeating pattern, wherein the line width w or the repeating pitch p of the repeating pattern has an exposure wavelength of λ,
When the numerical aperture of the projection optical system is NA, 0.25λ / N
A <w <0.5λ / NA or 0.5λ / NA <p <
A semiconductor integrated circuit that is pattern-exposed with light having a wavelength λ satisfying 1.0λ / NA of 150 nm or more. 47. The semiconductor integrated circuit according to claim 46, which includes a pattern having an angle of approximately 45 ° with two orthogonal directions.