JPH09120154A - Polarizing mask and its production as well as pattern exposure method and pattern projection aligner using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody the resolution equiv. to or higher than the resolution of the conventional phase shift method without the formation of such patterns of which the design is infeasible. SOLUTION: A halftone phase shifter 204 is arranged on the outer or inner side of a fine pattern group which is formed on a mask and has a polarization characteristic. This mask is irradiated with annular band-shaped illumination light in such a manner that the polarization direction is made rotationally symmetrical with respect to the optical axis on the pupil of the projecting optical system of this illumination light, by which the phase shifter is exposed with the transmitted light. The mask is otherwise irradiated with the annular band-shaped illumination light in non-polarization state and the transmitted light is passed through an analyzer which is arranged on the pupil and is rotationally symmetrical in the polarization direction, by which the phase shifter is exposed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization mask used for forming a fine circuit pattern, an exposure method and a projection exposure apparatus using this polarization mask, and more particularly to a pattern determined by the diffraction limit of light used for exposure. It concerns the exposure of patterns with line widths close to the dimensional limits.

[0002]

2. Description of the Related Art As semiconductor integrated circuits are becoming finer, they are approaching the area of the minimum line width that can be exposed and is determined by the diffraction limit of light. Therefore, in recent years, various devices called super-resolution techniques have been applied to masks and projection exposure apparatuses. The resolution R of the exposure optical system is determined by R = k ₁ λ / NA, where λ is the exposure wavelength and NA is the numerical aperture of the projection optical system.
Conventionally, it was considered that the limit of k ₁ was about 0.6 to 0.8.

Various measures have been taken over this limit, and attention has been paid to some extent as a method capable of solving the problem of a decrease in focus seismic intensity, which becomes increasingly severe with miniaturization. As typical techniques therefor, a phase shift method (developing a mask), an annular illumination method, a diagonal oblique illumination method (developing a projection exposure apparatus) and the like have been studied.

If the method of FIG.
As shown in (b) and (c), the phase of the transmitted light of the mask pattern is 180 degrees between the adjacent patterns of the repeated pattern.
By offsetting the angle, the light intensity between adjacent patterns of the pattern formed by the projection optical system becomes 0, and the separation between repetitive patterns can be made very good. However, this method cannot always change the phase by 180 ° between adjacent patterns when a two-dimensional pattern as shown in FIGS. 30 (a), 30 (b), and 30 (c) is obtained. A part that is not resolved more than the exposure method occurs.
This becomes a very large constraint in designing a pattern, and a pattern that cannot be designed occurs.

In the conventional exposure method, the method of FIG.
As shown in (a), the directivity σ of the illumination light (the ratio of the spread d of the illumination light on this pupil to the pupil diameter D of the projection optical system, that is,
σ = d / D) was about 0.5, while FIG.
As shown in (b), the spread of the illumination light on the pupil is made into an annular shape, and the outer diameter and the inner diameter of this annular area are set to about 0.7 and 0.5 with respect to the pupil diameter D, respectively. , MTF (Moduration Transfer Functio) of the high frequency part of the pattern
n) is high. 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. By doing so, the resolution for the xy-direction pattern in the figure is lower than that for the annular illumination, and the resolution is lower than that for the conventional illumination with the conventional 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, and in particular, the various super-resolution methods which are currently being actively studied.

Here, the problems are summarized as follows. The conventional phase shift method of is a method of obtaining the highest resolution among the current super-resolution methods, but if it is attempted to maintain this resolution, there are undesignable patterns such as two-dimensional patterns. This is a major obstacle in 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 xy and 45.
The resolution of the ° pattern will be significantly worse.

An object of the present invention is to provide a polarization mask that realizes a resolution equal to or higher than that of the conventional phase shift method without generating a pattern that makes it impossible to design, an exposure method using the same, and an exposure method using the same. It is to provide a projection exposure apparatus.

[0010]

In order to achieve the above object, in the present invention, light from an exposure illumination light source has a desired directivity on a polarizing mask (or a polarizing reticle) on which a desired original image pattern is drawn. Then, the transmitted light or the reflected light of the polarization mask is projected onto the object to be exposed through the projection optical system, and the following means are applied when the image from the original image pattern is exposed.

That is, the directivity of the illuminating light is so-called annular illumination or direct illuminating, and it depends on the pattern that gives the illuminating light that has passed through this pattern the polarization characteristic according to the direction of the pattern on the polarizing mask. A polarization mask is used. 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 polarization mask is not provided. Further, it is preferable to dispose a polarization element (or a light analysis element) whose polarization state is substantially rotationally symmetrical with respect to the pupil center near the pupil of the projection optical system.

As the pattern-dependent polarization mask, a mask 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 through this pattern are substantially parallel or orthogonal to each other is used. Further, the above-mentioned object can be achieved by using the above-mentioned polarization mask which is composed of a portion B which allows the illumination light to pass therethrough and a portion B which shields the illumination light. At this time, the amplitude transmittance of the portion B that substantially shields light from the portions A and B is preferably 30% or less of the amplitude transmittance of the portion A that transmits.
Further, 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 polarization mask illuminated by this irradiation light passes through the pupil of the projection optical system, The other is not passing through the eyes.

The means for imparting the polarization characteristic on the polarization mask can be realized by using a micro slit structure.
The fine 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. The width of this fine line is preferably set to about 1/2 or less of the wavelength λ of the illumination light. Furthermore, this thin line is excellent in conductivity and has a complex refractive index n and a light absorption coefficient k regardless of the wavelength of the exposure light.
It is better to use a stable material.

By using the above method, a fine semiconductor integrated circuit having a pattern structure which cannot be realized by the conventional phase shifter method is exposed. In addition, the directivity of conventional illumination light is
A fine semiconductor integrated circuit that cannot be resolved by so-called annular illumination or direct illumination and has no restriction on the pattern direction 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 /
NA <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 0 °, a pattern that cannot be exposed by the conventional phase shifter method, and a repeating pattern. The line width W or the repeating pitch p of the repeating pattern is λ, the exposure wavelength is λ, the projection optical system. Where NA is 0.25λ / NA <W <0.5λ / NA or 0.5λ / NA <p <1.0λ / NA.

The operation of the present invention will be described with reference to FIGS. 32 to 36.

As shown in FIG. 32, 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 illuminates the polarization mask on which this pattern is drawn is
This is so-called ring-shaped illumination or directional illumination. For example, in the case of the ring-shaped illumination shown in the figure, the luminous fluxes B ₁ , B ₂ , B ₃ , B ₄ , B ₅ , B from each direction that irradiate this pattern are shown. ₆ ,
Considering B ₇ and B ₈ , these lights are B ₁ ′, B ₂ ′, and B ₂ ′ on the pupil of the projection lens, respectively, without the polarization mask.
_{B 3 ', B 4',} B 5 ', B 6', B 7 ', B 8' reaches the position of the.

If the polarization of the eight light beams is perpendicular to the optical axis of the projection optical system and is orthogonal to the line passing through the optical axis, the light beams B ₁ and B ₅ of these eight light beams are in the y direction. However, the light fluxes of B ₃ and B ₇ hardly pass through this pattern. Further, B ₂ , B ₄ , B ₆ , and B _{8 in the} middle are transmitted almost by half. B ₁ and the light flux B ₅ after passing through the pattern, the principal ray reaches the "B ₅ and" pupil on B ₁ in the projection optical system, the diffraction in the x direction around the zero-order light B ₁ 'and B _5' The light spreads.

It is well known that a high resolution can be obtained if the diffracted light in the x direction can pass through the pupil in a wide range. Therefore, the light flux of B ₁ and B ₅ in the present invention, almost passes through the y-direction of the pattern, giving a high resolution, B ₃ and B ₇
As can be clearly understood from this description, the light flux of passes through only a narrow range of the diffracted light on the pupil and lowers the resolution.However, since this light flux hardly passes through this pattern, it does not drop the resolution and is fine. It is possible to expose the pattern. The light of B ₂ , B ₄ , B ₆ , and B ₈ is the 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, only the illumination light having the highest resolution is effectively used in the present invention, so that the resolution which cannot be achieved by the conventional method can be obtained. Further, due to the polarization property of the illumination light and the polarization transmission property depending on the pattern direction, not only the pattern in the y direction but also the pattern oriented in any direction can achieve high resolution. The fact that high resolution can be obtained without depending on the direction and arrangement of the patterns has not been realized by the conventional phase shift method.

In order to compare the operation of the present invention with the conventional super-resolution method, FIG. 3 and a method of simulating the resolution situation of the pattern obtained by the present invention are shown in FIG.
3, FIG. 34, FIG. 35, and FIG. In order to demonstrate the effects of the present invention, the pattern width to be exposed is 0.25 μm, the exposure is performed with the i-line of a mercury lamp, the wavelength is 365 nm, and the numerical aperture NA of the projection optical system is 0.57. FIG. 33 shows the resolution situation in the case of annular illumination, and it can be seen that the pattern separation is poor even at the in-focus position.

FIG. 34 shows a resolution situation in the case of oblique illumination with respect to the pattern in the xy directions, which is improved as compared with the case of the annular illumination, but the defocus of 0.5 μm deteriorates the pattern separation. . However, in the resolution situation of the pattern of 45 ° in the xy directions in FIG. 35, the resolution is deteriorated as compared with the annular illumination. FIG. 36 shows the resolution of a pattern obtained by the exposure method of the present invention with a normal mask, that is, with the mask used in FIGS. Therefore, it can be seen that a good image is obtained in a wider focus range as compared with FIGS. 33, 34, and 35.

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 uses a mask having a phase difference of 180 ° from each other, and the resolution is further improved by subjecting the mask to annular illumination or direct illumination. At this time, a high resolution can be obtained by setting the complex amplitude transmissivity of the part B that substantially shields light to the part of A and B to 30% or less of the complex amplitude transmissivity of the part A that transmits. Especially, if it is set to 22%, the separation between the patterns becomes the best.

This is because when the complex 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 the two lights become substantially equal to each other, and 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 symmetrical 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 particular, in this case, even when the directivity σ of the illumination is large, it is possible to perform exposure with a high resolution without causing a relative decrease in the contrast in the high frequency region of the resolution pattern that has conventionally occurred.

[0026]

1 is a first embodiment of the present invention, which is an example of forming a repetitive pattern using a negative resist. FIG. 1A is a sectional view of the polarization mask of the present invention. FIG. 1B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 1C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 1D shows a sectional view of a negative resist pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 1E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate.

In FIG. 1A, W is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics exists. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength. For the fine light-shielding film pattern 205, a light-shielding film material having excellent conductivity such as aluminum and tin, having a constant complex refractive index n and a constant light absorption coefficient k regardless of wavelength is used.

The fine light-shielding film pattern 205 is formed on a transparent substrate 2032 such as quartz glass by using an EB (Electron Beam) drawing device. The halftone phase shifter 204 is formed on the transparent substrate 2031 different from the fine light shielding film pattern 205 using an EB drawing device, and this portion (light shielding portion 202)
The light transmittance is about 5 to 20%. The halftone phase shifter 204 has a two-layer structure of different materials including an absorber (corresponding to a light-shielding portion) having a thin chromium film and a silicon dioxide-based shifter, or a single material having a single-layer or multi-layer halftone. Is used. Material is chrome (Cr
O, CrON), molybdenum-based (MoSiO, MoSi)
ON) and silicon nitride based (SiN).

Illumination light incident from below the transparent substrate 2032 transmits polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent substrate 2031 exists is as described above. Only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205. Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line.

The boundary between the outermost pattern of the fine light-shielding film pattern 205 and the halftone phase shifter 204 is controlled by controlling the transmittance of the halftone phase shifter 204, as shown in FIG. Can be improved. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 1 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, only the portion having the width W of the light transmitting portion 201 remains during the development, as shown in FIG. The resulting negative resist pattern is obtained. The circuit pattern shown in FIG. 1E is obtained by etching the negative resist pattern shown in FIG.

As described above, by combining the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength and the halftone phase shifter 204 whose transmittance is controlled, excellent pattern separation is achieved. It becomes possible to expose a pattern of resolution.

Further, the phase shifter material is used as the transparent substrate 203.
1. In the example in which the halftone material is formed on the transparent substrate 2032, or in the example in which the halftone phase shifter 204 and the fine light shielding film pattern 205 are formed on the same surface of one transparent substrate, the same effect as in FIG. 1 can be obtained. Even when a positive resist is used, the same effect as in FIG. 1 can be obtained.

2A and 2B are plan views of the polarization mask of FIG. 1, and FIG. 2C is a plan view of the circuit pattern on the wafer when the polarization mask of FIG. is there.

As shown in FIG. 2A, the transparent substrate 203
1 has a halftone phase shifter 204 and a mask overlay mark 210 formed thereon. A fine light-shielding film pattern 205 and a mask overlay mark 210 are formed on the transparent substrate 2032 of FIG. 2B. Therefore, when the transparent substrates 2031 and 2032 are superposed and exposed, the center coordinates of the respective mask overlay marks 210 are read and pre-positioned by the overlay measuring device, so that the halftone phase shifter 204 and the fine light-shielding film are formed. As a result, relative displacement with the pattern 205 does not occur, and as shown in FIG. 2C, it is possible to expose a high resolution pattern with excellent pattern separation.

FIG. 3 shows a second embodiment of the present invention, which is an example of forming a repetitive pattern using a negative resist. FIG. 3A is a sectional view of the polarization mask of the present invention. FIG.
FIG. 3B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 3C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 3D shows a cross-sectional view of the negative resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 3E shows a cross-sectional view of the circuit pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate.

W in FIG. 3 (a) is the width of the light transmitting portion 201 on which the pattern is exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

The fine light-shielding film pattern 205 is the transparent substrate 20.
32 is formed by using an EB drawing device. The halftone phase shifter 204 is formed on the transparent substrate 2031 different from the fine light-shielding film pattern 205 using an EB drawing device, and the light transmittance of this portion (light-shielding portion 202) is about 5 to 20%. Further, the fine light-shielding film pattern 2 on the transparent substrate 2032
The light-shielding film pattern 211 is formed on the surface where 05 is located at a slightly separated position by the same method. The same material as the fine light-shielding film pattern 205 is used for the light-shielding film pattern 211. The light shielding film pattern 211 is arranged so that the inner edge thereof is slightly outside the inner edge of the halftone phase shifter 204.

Illumination light incident from below the transparent substrate 2032 transmits polarized light in the edge direction of the pattern at the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent substrate 2031 exists is as described above. Only about 5 to 30% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted. The complex amplitude becomes 0 in the portion where the light shielding film pattern 211 is arranged.

The complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 3 (b). The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205.
Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line.

At the boundary between the outer and inner patterns of the fine light-shielding film pattern 205 and the halftone phase shifter 204, the transmittance of the halftone phase shifter 204 is controlled to improve the contrast as shown in FIG. Can be made. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 3 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the developing limit of the negative type resist, the portion having the width W of the light transmitting portion 201 remains during the developing and is shown in FIG. It becomes a negative resist pattern. The circuit pattern shown in FIG. 3E is obtained by etching the negative resist pattern shown in FIG.

As described above, by combining the fine light-shielding film pattern 205 and the light-shielding film pattern 211 having the opening width Δw of about ½ of the exposure wavelength and the halftone phase shifter 204 whose transmittance is controlled, the outside The contrast of the repetitive pattern part of is increased, and it becomes possible to expose a pattern of high resolution with excellent separation.

Further, the phase shifter material is used as the transparent substrate 203.
1. An example in which a halftone material having a light shielding film pattern 211 is formed on a transparent substrate 2032, or a halftone phase shifter 204 having a light shielding film pattern 211 and a fine light shielding film pattern 205 on the same surface of one transparent substrate. The same effect as that of FIG. Even when a positive resist is used, the same effect as in FIG. 3 can be obtained.

FIGS. 4A and 4B are plan views of the polarization mask of FIG. FIG. 4C is a plan view of a circuit pattern on the wafer when projection exposure is performed using the polarizing mask of FIG. 3 as an original plate. As shown in FIG. 4A, the transparent substrate 2031
A halftone phase shifter 204 and a mask overlay mark 210 are formed on the. A fine light-shielding film pattern 205, a light-shielding film pattern 211, and a mask overlay mark 210 are formed on the transparent substrate 2032 of FIG. 4B. Therefore, when the transparent substrates 2031 and 2032 are superposed and exposed, the center coordinates of the respective mask overlay marks 210 are read and pre-positioned by the overlay measuring device, so that the halftone phase shifter 204 and the fine light-shielding film are formed. Relative positional displacement between the pattern 205 and the light-shielding film pattern 211 does not occur,
It becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG.

FIG. 5 shows Example 3 of the present invention, which is an example of forming a repeating pattern using a negative resist. FIG. 5A is a sectional view of the polarization mask of the present invention. FIG.
FIG. 5B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 5C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 5D shows a cross-sectional view of the negative resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 5E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate.

In FIG. 5A, W is the width of the light transmitting portion 201 on which the pattern is exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

First, the transparent film material 2 is formed on the transparent substrate 203.
12 is deposited by the sputtering method. In order to improve the polarization characteristics of the fine light-shielding film pattern 205, the deposited film thickness is d ₁ =
It is 1 μm or more. Next, a fine line for the fine light-shielding film pattern 205 is carved by a focused ion beam processing device.
After finishing the fine line processing, a light-shielding film material such as aluminum or tin having excellent conductivity and having a constant complex refractive index n and a constant light absorption coefficient k regardless of wavelength is deposited by a sputtering method. After this, CM
Polishing processing such as P (Chemical Mechanical Polishing) is performed so that the light shielding film material remains only in the fine line portion. The halftone phase shifter 204 is a transparent film material 212.
The light transmittance of this portion (light shielding portion 202) is about 5 to 20%. The film thickness d ₂ is about 1/10 of the film thickness d ₁ of the transparent film material 212.

Illumination light incident from below the transparent substrate 203 transmits the polarized light in the edge direction of the pattern at the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent film material 212 exists. As described above, only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted.

The complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 5 (b). The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205.
Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line.

At the boundaries between the patterns outside and inside the fine light-shielding film pattern 205 and the halftone phase shifter 204, the transmittance of the halftone phase shifter 204 is controlled to improve the contrast as shown in FIG. Can be made. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 5 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, the portion having the width W of the light transmitting portion 201 remains during the development and is shown in FIG. It becomes a negative resist pattern. The circuit pattern shown in FIG. 5E is obtained by etching the negative resist pattern shown in FIG.

As described above, by combining the transparent film material 212 including the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength, and the halftone phase shifter 204 whose transmittance is controlled. It is possible to expose a high resolution pattern with excellent separation.

When a positive resist is used, the same effect as in FIG. 5 can be obtained.

FIG. 6A is a plan view of the polarization mask of FIG.
FIG. 6B is a plan view of a circuit pattern on the wafer when projection exposure is performed using the polarizing mask of FIG. 5 as an original plate.

As shown in FIG. 6A, the transparent substrate 203
Includes a transparent film material 212 including a fine light-shielding film pattern 205.
And a halftone phase shifter 204 are formed.
Therefore, if the transparent substrate 203 is exposed as it is, it becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG. 6B.

FIG. 7 shows Example 4 of the present invention, which is an example of forming a repetitive pattern using a negative resist. FIG. 7A is a sectional view of the polarization mask of the present invention. FIG.
FIG. 7B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 7C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 7D shows a sectional view of a negative resist pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 7E shows a sectional view of a circuit pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate.

In FIG. 7A, W is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having a polarization characteristic is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

A transparent film material 212, a fine light-shielding film pattern 205, and a halftone phase shifter 20 are formed on the transparent substrate 203.
4 is formed in the same manner as in FIG. Further, the light-shielding film pattern 211 is EB-formed on the halftone phase shifter 204.
It is formed by a drawing device. The inner edge of the light shielding film pattern 211 is arranged outside the inner edge of the halftone phase shifter 204.

Illumination light incident from below the transparent substrate 203 transmits polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent film material 212 exists is the above-mentioned. As described above, only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted. Further, since the portion where the light shielding film pattern 211 is provided is completely shielded from light, the complex amplitude becomes zero.

The complex amplitude transmittance of the light immediately after passing through this polarization mask is as shown in FIG. 7B. The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205.
Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line.

At the boundaries between the patterns on the outer and inner sides of the fine light-shielding film pattern 205 and the halftone phase shifter 204, the transmittance of the halftone phase shifter 204 is controlled to improve the contrast as shown in FIG. Can be made. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 7 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, the portion of the width W of the light transmitting portion 201 remains during the development and is shown in FIG. It becomes a negative resist pattern. The negative resist pattern shown in FIG. 7 (d) is etched to obtain the circuit pattern shown in FIG. 7 (e).

As described above, the transparent film material 212 including the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength, the halftone phase shifter 204 and the light-shielding film pattern 211 whose transmittance is controlled. By combining the above, the contrast of the edge portion of the outermost repeating pattern is improved, and it becomes possible to expose a high resolution pattern with excellent separation.

Also, when a positive resist is used, the same effect as in FIG. 7 can be obtained.

FIG. 8A is a plan view of the polarization mask of FIG.
FIG. 8B is a plan view of a circuit pattern on a wafer when projection exposure is performed using the polarizing mask of FIG. 7 as an original plate.

As shown in FIG. 8A, the transparent substrate 203
Includes a transparent film material 212 including a fine light-shielding film pattern 205.
And halftone phase shifter 204 and light shielding film pattern 2
And 11 are formed. Therefore, the transparent substrate 203
8B is exposed as it is, it becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG. 8B.

FIG. 9 shows Example 5 of the present invention, which is an example of forming an isolated pattern using a negative resist. FIG. 9A is a sectional view of the polarization mask of the present invention. FIG.
FIG. 9B shows the complex amplitude transmittance of the transmitted light of the illumination light incident from the lower side of FIG. FIG. 9C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 9D shows a sectional view of the negative resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 9E shows a sectional view of a circuit pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate.

W of FIG. 9A is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

The fine light-shielding film pattern 205 is the transparent substrate 20.
32 is formed by using an EB drawing device. The halftone phase shifter 204 is formed on the transparent substrate 2031 different from the fine light-shielding film pattern 205 using an EB drawing device, and the light transmittance of this portion (light-shielding portion 202) is about 5 to 20%.

Illumination light incident from below the transparent substrate 2032 transmits the polarized light in the edge direction of the pattern at the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent substrate 2031 exists is as described above. Only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 9B. The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205. Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line. Further, since there is no pattern outside the fine light-shielding film pattern 205, the complex amplitude transmittance is 10
0%.

At the boundary between the outermost pattern of the fine light-shielding film pattern 205 and the halftone phase shifter 204, the transmittance of the halftone phase shifter 204 is controlled to improve the contrast as shown in FIG. Can be made. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 9 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, only the portion of the width W of the light transmitting portion 201 remains during the development, and as shown in FIG. The resulting negative resist pattern is obtained. The circuit pattern shown in FIG. 9E is obtained by etching the negative resist pattern shown in FIG. 9D.

As described above, by combining the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength and the halftone phase shifter 204 whose transmittance is controlled, excellent pattern separation is achieved. It becomes possible to expose a pattern of resolution. The phase shifter material is transparent substrate 2031 and the halftone material is transparent substrate 2032.
The same effect as in FIG. 9 can be obtained in the case of forming the halftone phase shifter 204 and the fine light shielding film pattern 205 on the same surface of one transparent substrate.

FIGS. 10A and 10B are plan views of the polarization mask of FIG.

As shown in FIG. 10A, the transparent substrate 20
A halftone phase shifter 204 and a mask overlay mark 210 are formed at 31. A fine light-shielding film pattern 205 and a mask overlay mark 210 are formed on the transparent substrate 2032 of FIG. Therefore, when the transparent substrates 2031 and 2032 are superposed and exposed, the center coordinates of the respective mask overlay marks 210 are read and pre-positioned by the overlay measuring device, so that the halftone phase shifter 204 and the fine light-shielding film are formed. A relative displacement with the pattern 205 does not occur, and it becomes possible to expose a high resolution pattern with excellent pattern separation.

FIG. 11 shows Example 6 of the present invention, which is an example of forming an isolated pattern using a negative resist.
FIG. 11A is a sectional view of the polarization mask of the present invention. FIG. 11B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 11C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 11D shows a cross-sectional view of the negative resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 11E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. W of FIG. 11A is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics exists. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

The fine light-shielding film pattern 205 is the transparent substrate 20.
32 is formed by using an EB drawing device. The halftone phase shifter 204 is formed on the transparent substrate 2031 different from the fine light-shielding film pattern 205 using an EB drawing device, and the light transmittance of this portion (light-shielding portion 202) is about 5 to 20%. Further, the fine light-shielding film pattern 2 on the transparent substrate 2032
The light-shielding film pattern 211 is formed on the surface where 05 is located at a slightly separated position by the same method. The light shielding film pattern 211 is arranged so that the inner edge thereof is slightly outside the inner edge of the halftone phase shifter 204.

Illumination light incident from below the transparent substrate 2032 transmits the polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent substrate 2031 exists is as described above. Only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted. The complex amplitude becomes 0 in the portion where the light shielding film pattern 211 is arranged.

The complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 11 (b). The complex amplitude transmittance of the portion of the light transmitting portion 201 has a complex amplitude of 0 in the portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 20.
Since No. 5 is not resolved at the exposure wavelength, the distribution actually becomes as shown by the solid line.

The boundary between the pattern outside the fine light-shielding film pattern 205 and the halftone phase shifter 204 is
By controlling the transmittance of the halftone phase shifter 204, the contrast can be improved as shown in FIG. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 11 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the developing limit of the negative resist, the portion of the light transmitting portion 201 (W) remains during the developing and is shown in FIG. 11 (d). It becomes a negative resist pattern.
The circuit pattern shown in FIG. 11E is obtained by etching the negative resist pattern shown in FIG.

As described above, by combining the fine light-shielding film pattern 205 and the light-shielding film pattern 211 having the opening width Δw of about 1/2 of the exposure wavelength and the halftone phase shifter 204 whose transmittance is controlled, the isolation is achieved. The contrast of the edge portion of the pattern becomes high, and it becomes possible to expose a high resolution pattern having excellent separation.

The phase shifter material is used as the transparent substrate 203.
1. An example in which a halftone material having a light shielding film pattern 211 is formed on a transparent substrate 2032, or a halftone phase shifter 204 having a light shielding film pattern 211 and a fine light shielding film pattern 205 on the same surface of one transparent substrate. The same effect as that of FIG.

The same effect as in FIG. 11 can be obtained when a positive resist is used.

12 (a) and 12 (b) are plan views of the polarization mask of FIG. As shown in FIG. 12A, a halftone phase shifter 204 and a mask overlay mark 210 are formed on the transparent substrate 2031. FIG.
The fine light-shielding film pattern 20 is formed on the transparent substrate 2032 of FIG.
5 and the light shielding film pattern 211 and the mask overlay mark 210 are formed. Therefore, the transparent substrate 203
When superimposing and exposing 1 and 2032, the central coordinates of each mask overlay mark 210 are read,
If you position in advance with the overlay measuring device,
Halftone phase shifter 204 and fine light-shielding film pattern 2
05 and the light-shielding film pattern 211 are not displaced relative to each other, and it is possible to expose a high-resolution pattern with excellent pattern separation.

FIG. 13 is a plan view of an isolated pattern on a wafer when projection exposure is performed using the polarizing mask of FIG. 11 as an original plate.

FIG. 14 shows Example 7 of the present invention, which is an example of forming an isolated pattern using a negative resist.
FIG. 14A is a sectional view of the polarization mask of the present invention. FIG. 14B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 14C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 14D shows a cross-sectional view of the negative resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 14E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. W in FIG. 14A is the width of the light transmitting portion 201 of the pattern to be exposed, and at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present therein. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

A transparent film 203, a fine light-shielding film pattern 205, and a halftone phase shifter 20 are formed on a transparent substrate 203.
4 is formed in the same manner as in FIG.

Illumination light incident from below the transparent substrate 203 transmits polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent film material 212 exists is the above-mentioned. As described above, only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted.

The complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. The complex amplitude transmittance of the portion of the light transmitting portion 201 has a complex amplitude of 0 in the portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 20.
Since No. 5 is not resolved at the exposure wavelength, the distribution actually becomes as shown by the solid line.

The boundary between the pattern outside the fine light-shielding film pattern 205 and the halftone phase shifter 204 is
By controlling the transmittance of the halftone phase shifter 204, the contrast can be improved as shown in FIG. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 14 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, the portion having the width W of the light transmitting portion 201 remains during the development and is shown in FIG. It becomes a negative resist pattern.
The circuit pattern shown in FIG. 14E is obtained by etching the negative resist pattern shown in FIG.

As described above, by combining the transparent film material 212 including the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength, and the halftone phase shifter 204 whose transmittance is controlled. It is possible to expose a high resolution pattern with excellent separation.

FIG. 15A is a plan view of the polarization mask of FIG. 14, and FIG. 15B is a plan view of a circuit pattern on the wafer when projection exposure is performed using the polarization mask of FIG. 14 as an original plate.

As shown in FIG. 15A, the transparent substrate 20
3 is a transparent film material 21 including a fine light-shielding film pattern 205.
2 and a halftone phase shifter 204 are formed. Therefore, if the transparent substrate 203 is exposed as it is, it becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG.

FIG. 16 shows an eighth embodiment of the present invention, which is an example of forming an isolated pattern using a negative resist.
FIG. 16A is a sectional view of the polarization mask of the present invention. FIG. 16B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 16C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 16D shows a sectional view of a negative resist pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 16E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. W of FIG. 16A is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

On the transparent substrate 203, the transparent film material 212, the fine light-shielding film pattern 205, and the halftone phase shifter 20.
4 is formed in the same manner as in FIG. Further, the light-shielding film pattern 211 is EB-formed on the halftone phase shifter 204.
It is formed by a drawing device. The inner edge of the light shielding film pattern 211 is arranged outside the inner edge of the halftone phase shifter 204.

Illumination light incident from below the transparent substrate 203 transmits the polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent film material 212 exists is the above-mentioned. As described above, only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted. Further, since the portion where the light shielding film pattern 211 is provided is completely shielded from light, the complex amplitude becomes zero.

The complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 16 (b). The complex amplitude transmittance of the portion of the light transmitting portion 201 has a complex amplitude of 0 in the portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 20.
Since No. 5 is not resolved at the exposure wavelength, the distribution actually becomes as shown by the solid line.

The boundary between the pattern outside the fine light-shielding film pattern 205 and the halftone phase shifter 204 is
By controlling the transmittance of the halftone phase shifter 204, the contrast can be improved as shown in FIG. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 16 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the negative resist, the portion having the width W of the light transmitting portion 201 remains during the development and is shown in FIG. It becomes a negative resist pattern.
The circuit pattern shown in FIG. 16 (e) is obtained by etching the negative resist pattern shown in FIG. 16 (d).

As described above, the transparent film material 212 including the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength, the halftone phase shifter 204 and the light-shielding film pattern 211 whose transmittance is controlled. By combining the above, the contrast of the edge portion of the isolated pattern is improved, and it becomes possible to expose a high resolution pattern with excellent separation.

FIG. 17A is a plan view of the polarization mask of FIG. 16, and FIG. 17B is a plan view of a circuit pattern on a wafer when projection exposure is performed using the polarization mask of FIG. 16 as an original plate.

As shown in FIG. 17A, the transparent substrate 20
3 is a transparent film material 21 including a fine light-shielding film pattern 205.
2, the halftone phase shifter 204 and the light shielding film pattern 211 are formed. Therefore, the transparent substrate 20
If 3 is exposed as it is, it becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG.

FIG. 18 shows Example 9 of the present invention, which is an example of forming an isolated pattern using a positive resist.
FIG. 18A is a sectional view of the polarization mask of the present invention. FIG. 18B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 18C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 18D shows a sectional view of the positive resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 18E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate.

In FIG. 18A, W is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics exists. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

The fine light-shielding film pattern 205 is the transparent substrate 20.
32 is formed by using an EB drawing device. The halftone phase shifter 204 is formed on the transparent substrate 2031 different from the fine light-shielding film pattern 205 using an EB drawing device, and the light transmittance of this portion (light-shielding portion 202) is about 5 to 20%.

Illumination light incident from below the transparent substrate 2032 transmits the polarized light in the edge direction of the pattern in the portion where the fine light-shielding film pattern 205 exists, and the portion where the halftone phase shifter 204 on the transparent substrate 2031 exists is as described above. Only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the complex amplitude transmittance of light immediately after passing through this polarization mask is as shown in FIG. 18B. The complex amplitude transmittance of the light transmitting portion 201 has a complex amplitude of 0 in a portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 205. Is not resolved at the exposure wavelength, so the distribution actually becomes as shown by the solid line. Further, since there is no pattern outside the fine light-shielding film pattern 205, the complex amplitude transmittance is 10
0%.

At the boundary portion between the innermost pattern of the fine light-shielding film pattern 205 and the halftone phase shifter 204, the transmittance of the halftone phase shifter 204 is controlled to improve the contrast as shown in FIG. Can be made. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 18 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the positive resist, the width W of the light transmission portion 201 and the portion without the pattern outside thereof are removed during the development. The positive resist pattern shown in FIG. The result obtained by etching the positive resist pattern shown in FIG.
It is a circuit pattern shown in (e).

As described above, by combining the fine light-shielding film pattern 205 whose opening width Δw is about ½ of the exposure wavelength and the halftone phase shifter 204 whose transmittance is controlled, excellent pattern separation is achieved. It becomes possible to expose a pattern of resolution. The phase shifter material is transparent substrate 2031 and the halftone material is transparent substrate 2032.
18 and the example in which the halftone phase shifter 204 and the fine light shielding film pattern 205 are formed on the same surface of one transparent substrate, the same effect as in FIG. 18 can be obtained.

19 (a) and 19 (b) are plan views of the polarization mask of FIG. As shown in FIG. 19A, a halftone phase shifter 204 and a mask overlay mark 210 are formed on the transparent substrate 2031. FIG.
The fine light-shielding film pattern 20 is formed on the transparent substrate 2032 of FIG.
5 and a mask overlay mark 210 are formed.
Therefore, when the transparent substrates 2031 and 2032 are superposed and exposed, the respective mask overlay marks 2
If the center coordinates of 10 are read and pre-positioned with the overlay measuring device, the halftone phase shifter 2
04 and the fine light-shielding film pattern 205 are not displaced relative to each other, and it is possible to expose a high resolution pattern with excellent pattern separation.

FIG. 20 shows Example 10 of the present invention, which is an example of forming an isolated pattern using a positive resist.
FIG. 20A is a sectional view of the polarization mask of the present invention. FIG. 20B shows the complex amplitude transmittance of the transmitted light of the illumination light that is incident from below in FIG. FIG. 20C shows the light intensity on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 20D shows a sectional view of a positive resist pattern on the wafer when projection exposure is performed using this polarizing mask as an original plate. FIG. 20E shows a sectional view of a circuit pattern on a wafer when projection exposure is performed using this polarizing mask as an original plate. W of FIG. 20A is the width of the light transmitting portion 201 of the pattern to be exposed, in which at least one conductive fine light-shielding film pattern 205 having polarization characteristics is present. This number is selected so that the width Δw of the opening of the light transmitting portion 201 is about ½ of the exposure wavelength.

The transparent film 203, the fine light-shielding film pattern 205, and the halftone phase shifter 20 are formed on the transparent substrate 203.
4 is formed in the same manner as in FIG.

Illumination light incident from below the transparent substrate 203 transmits the polarized light in the edge direction of the pattern in the portion where the fine light shielding film pattern 205 is present, and the portion where the halftone phase shifter 204 is provided on the transparent film material 212 is the above-mentioned. As described above, only about 5 to 20% is transmitted. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted. Further, the transmittance of the transparent film material 212 where there is no pattern is 100%.

FIG. 20B shows the complex amplitude transmittance of light immediately after passing through this polarization mask. The complex amplitude transmittance of the portion of the light transmitting portion 201 has a complex amplitude of 0 in the portion where the fine light-shielding film pattern 205 is present, so theoretically the transmittance distribution is as shown by the dotted line, but the fine light-shielding film pattern 20.
Since No. 5 is not resolved at the exposure wavelength, the distribution actually becomes as shown by the solid line.

The boundary between the pattern inside the fine light-shielding film pattern 205 and the halftone phase shifter 204 is
By controlling the transmittance of the halftone phase shifter 204, the contrast can be improved as shown in FIG. Therefore, as a whole, the complex amplitude transmissivity in which the contrast of the edge portion of the width W of the pattern to be resolved is large is obtained.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer is as shown in FIG. 20 (c). Since the light intensity of the portion substantially shielded by the halftone phase shifter 204 is lower than the development limit of the positive resist, the width W portion of the light transmitting portion 201 and the portion without pattern are removed at the time of development. The positive resist pattern shown in 20 (d) is obtained. The circuit pattern shown in FIG. 20E is obtained by etching the positive resist pattern shown in FIG.

As described above, by combining the transparent film material 212 including the fine light-shielding film pattern 205 having the opening width Δw of about ½ of the exposure wavelength, and the halftone phase shifter 204 whose transmittance is controlled. It is possible to expose a high resolution pattern with excellent separation.

FIG. 21 (a) is a plan view of the polarization mask of FIG. 20, and FIG. 21 (b) is a plan view of a circuit pattern on a wafer when projection exposure is performed using the polarization mask of FIG. 20 as an original plate.

As shown in FIG. 21A, the transparent substrate 20
3 is a transparent film material 21 including a fine light-shielding film pattern 205.
2 and a halftone phase shifter 204 are formed. Therefore, if the transparent substrate 203 is exposed as it is, it becomes possible to expose a high resolution pattern with excellent pattern separation as shown in FIG.

FIG. 22 is a plan view of an isolated pattern on a wafer when projection exposure is performed using the polarizing mask of FIGS. 18 and 20 as an original plate.

FIG. 23 is a diagram showing the principle of the halftone type phase shifter. 23A is a cross-sectional view of a mask having a halftone phase shifter formed thereon, FIG. 23B is a complex amplitude transmittance of light transmitted through the mask, and FIG. 23C is a projection exposure using the mask as an original plate. FIG. 23D shows the complex amplitude transmittance of light on the wafer, and the light intensity distribution on the wafer when projection exposure is performed using the mask as the original plate.

In FIG. 23A, the halftone phase shifter 204 is formed on the transparent substrate 203 by an EB drawing device, and the portion with the halftone phase shifter 204 is the light shielding portion 202 and the portion without the halftone phase shifter 204. Becomes the light transmitting portion 201.

Illumination light incident from below the transparent substrate 203 is 100% at a portion without the halftone phase shifter 204.
A part of the halftone phase shifter 204 transmits only about 5 to 20% as described above. Since the halftone phase shifter 204 is provided with a 180 ° phase shifter, the phase of the light in this portion is inverted.

The complex amplitude transmittance of light immediately after passing through this mask is as shown in FIG. 23 (b). The complex amplitude transmittance of the portion of the light transmitting portion 201 is 100%, but the portion with the halftone phase shifter 204 is 5 to 20% as described above.
Since the light is transmitted only to some extent and the phase is inverted, the distribution shown by the solid line is obtained.

FIG. 23C shows the complex amplitude transmittance of light on the wafer when projection exposure is performed using a mask as an original plate. The complex amplitude transmittance of only the light transmitting portion 201 is as shown by the dotted line portion 52, and the complex amplitude transmittance of only the light shielding portion 202 is as shown by the dotted line portion 53. Since the light shielding portion 202 and the light transmitting portion 201 are continuous, the distribution of the sum of the dotted line portion 52 and the dotted line portion 53 is actually obtained, and the transmittance distribution is similar to that of the solid line portion 51. Therefore, by adjusting the transmittance of the halftone phase shifter 204, the complex amplitude transmittance of light on the wafer corresponding to the central portion of the halftone phase shifter 204 can be made zero.

Since the light intensity distribution is proportional to the square of the complex amplitude transmittance, the light intensity on the wafer corresponding to the central portion of the halftone phase shifter 204 is also zero. Therefore, FIG.
As shown in (d), a light intensity distribution with high contrast can be obtained on the wafer.

FIG. 24 is a detailed view of an example of the mask overlay mark. The inner peripheral mark 2102 is formed on the transparent substrate 203.
, And the halftone phase shifter 204 is formed thereon. An outer peripheral mark having an arbitrary phase φ of light is formed on the outer side thereof. By using the mask overlay mark thus formed, there is an effect that the setup time for mask overlay can be shortened when exposure is performed with a polarization mask using two transparent substrates.

FIG. 25 shows an embodiment in which the length l of the long side of the repeating pattern is shorter than that of the exposure area. In this case, the minute light shielding film patterns 2051, 2052, 2053 are arranged on the outer peripheral portion of the halftone phase shifter 204 as shown in the figure. Then, the outer peripheral portion of the halftone phase shifter 204 serves as a light transmitting portion and the portion having the halftone phase shifter 204 serves as a light shielding portion, so that it is possible to expose a high resolution pattern with excellent pattern separation.

FIG. 26 (a) shows an example of an isolated pattern having chamfered four corners, and FIG. 26 (b) shows an example of an isolated pattern having four arcs.

FIG. 27 shows an embodiment of the projection exposure apparatus of the present invention.

FIG. 27A shows a projection exposure apparatus according to the present invention.
1 is illumination light. The method of forming the illumination light will be described in detail later, but B ₀ , B ₉₀ , which are partial lights of the illumination light,
B ₁₈₀ and B ₂₇₀ each have the linearly polarized light shown in the figure, and when the polarization mask 2 is not provided, the reduction lens 3 which is a projection optical system.
The illumination light 11 on the pupil 3 of No. 1 irradiates on the ring-shaped band. 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 polarization mask 2 of the present invention, for example, patterns l ₁ , l ₂ , l ₃ and l ₄ oriented in the x and y directions are E.
B is drawn, and the polarization characteristics according to the direction in which these patterns face are given to the light that has been irradiated with these patterns and transmitted. Each of the embodiments shown in FIGS. 1 to 22 can be applied to the polarization mask 2.

That is, focusing on l ₂ shown in FIG. 27 (b), as shown in FIG. 28, the edge C ₁ C ₂ of the pattern is oriented in the y direction, and therefore linearly polarized light in the y direction is almost 100%. It transmits and blocks linearly polarized light in the x direction. Similarly, C ₁ C ₂
Illumination light having directivity of B ₉₀ and B ₂₇₀ is effectively transmitted through the portion surrounded by C ₃ C ₄ , and the diffracted light from this pattern is in a wide range on the pupil (corresponding to the pupil diameter). range)
The light that has spread to the area contributes to image formation, and a high-resolution pattern can be exposed on the exposed chip area 4 on the wafer 41.

This means that the pattern end face of C ₁ C ₂ 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 polarization mask 2, polarization is used well,
Each pattern effectively transmits only the directional illumination light, which is convenient for high resolution, and realizes high resolution exposure.

FIG. 28 is an enlarged view of the l ₂ pattern shown in FIG. 27 (b). It is an L-shaped isolated pattern, in which the fine light-shielding film patterns 2051 and 2052 are L-shaped, and the halftone phase shifter 204 surrounds the outer periphery.

[0139]

By using the polarizing mask of the present invention, the exposure method using the same, and the projection exposure apparatus using the same, the projection optical system of the conventional exposure apparatus can be used as it is to form a conventional resolution pattern. Patterns with much higher resolution can be exposed compared to the previous ones, semiconductor integrated circuit technology has improved significantly due to improved performance of semiconductor integrated circuits, semiconductor integrated circuit production yields have improved, and semiconductor integrated circuit manufacturing equipment investment has been significantly reduced. Various economic effects can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a polarization mask according to a first embodiment of the present invention.

FIG. 2 is a plan view of the polarization mask of FIG.

FIG. 3 is an explanatory diagram of a polarization mask according to a second embodiment of the present invention.

FIG. 4 is a plan view of the polarization mask shown in FIG.

FIG. 5 is an explanatory diagram of a polarization mask according to a third embodiment of the present invention.

6 is a plan view of the polarization mask of FIG.

FIG. 7 is an explanatory diagram of a polarization mask according to a fourth embodiment of the present invention.

FIG. 8 is a plan view of the polarization mask shown in FIG.

FIG. 9 is an explanatory diagram of a polarization mask according to a fifth embodiment of the present invention.

10 is a plan view of the polarization mask of FIG.

FIG. 11 is an explanatory diagram of a polarization mask according to a sixth embodiment of the present invention.

12 is a plan view of the polarization mask shown in FIG.

FIG. 13 is a plan view of a circuit pattern on a wafer when projection exposure is performed using the polarizing masks of FIGS. 9 and 11 as an original plate.

FIG. 14 is an explanatory diagram of a polarization mask according to a seventh embodiment of the present invention.

15 is a plan view of the polarization mask of FIG.

FIG. 16 is an explanatory diagram of a polarization mask according to an eighth embodiment of the present invention.

17 is a plan view of the polarization mask shown in FIG.

FIG. 18 is an explanatory diagram of a polarization mask according to an eighth embodiment of the present invention.

19 is a plan view of the polarization mask shown in FIG.

FIG. 20 is an explanatory diagram of a polarization mask according to a ninth embodiment of the present invention.

FIG. 21 is a plan view of the polarization mask shown in FIG.

22 is a plan view of a circuit pattern on a wafer when projection exposure is performed using the polarizing masks of FIGS. 18 and 20 as an original plate.

FIG. 23 is an explanatory diagram of a halftone phase shift mask.

FIG. 24 is an explanatory diagram of mask overlay marks used in a polarization mask.

FIG. 25 is a plan view of the polarization mask when the length l of the repeating pattern is shorter than the exposure area.

FIG. 26 is a plan view of an isolated pattern.

FIG. 27 is an explanatory diagram of a projection exposure apparatus using a polarization mask according to the present invention.

28 is an explanatory diagram of a polarization mask used in FIG. 27.

FIG. 29 is an explanatory diagram of a mask repetitive pattern according to a conventional phase shift method.

FIG. 30 is an explanatory diagram of a two-dimensional pattern of a mask by a conventional phase shift method.

FIG. 31 is an explanatory diagram of an illumination system of a conventional projection exposure apparatus.

FIG. 32 is an explanatory diagram of an illumination system of the projection exposure apparatus according to the present invention.

FIG. 33 is an explanatory diagram showing a state of resolution of a pattern obtained by conventional annular illumination.

FIG. 34 is an explanatory diagram showing a state of resolution of a pattern in the xy directions with respect to conventional oblique incident exposure from the 45 ° direction to the xy axes.

FIG. 35 is an explanatory diagram showing a resolution state 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 ° on the xy axis.

FIG. 36 is an explanatory view showing a situation of resolution of a pattern obtained by the exposure method according to the present invention.

[Explanation of symbols]

 Reference numeral 201 ... Light transmitting portion, 202 ... Light shielding portion, 203 ... Transparent substrate, 204 ... Halftone phase shifter, 205 ... Fine light shielding film pattern, 206 ... Negative resist, 207 ... Circuit forming material, 208 ... Wafer substrate.

Claims (25)

[Claims] 1. A tangential direction of an edge of a pattern of a polarizing mask which imparts a polarization characteristic depending on a direction of a pattern on a mask to an illumination light passing through the pattern and the illumination light. In the polarization mask in which the polarization directions of the light transmitted through the pattern are substantially parallel or substantially orthogonal, the pattern on the mask is composed of a portion A for transmitting the illumination light and a portion B for slightly transmitting but substantially shielding the light. The light transmitted through the portion B has a phase of 18
A polarization mask characterized in that the light intensity at the edge of the portion A on the object to be exposed becomes 0, which is different by 0 °. 2. The polarization mask according to claim 1, wherein the amplitude transmittance of the portion B that substantially shields the light is substantially 30% or less of the amplitude transmittance of the portion A that transmits the light. 3. The amplitude transmissivity of the substantially light-shielding portion B is effectively approximately 22 with respect to the amplitude transmissivity of the transmitting portion A.
%, The polarizing mask according to claim 2. 4. The polarization mask according to claim 1, wherein the substantially light-shielding portion B exists only near the light-transmitting portion A. 5. The polarizing mask according to claim 4, wherein the transparent portion A and the substantially light-shielding portion B are formed on different transparent substrates and face each other with an air layer in between. 6. Of the above-mentioned substantially light-shielding portion B, only materials having a phase different from that of the portion A by 180 ° face each other with the rest of the portion B and the portion A sandwiching an air layer, and are formed on different transparent substrates. The polarizing mask according to claim 4, wherein 7. The polarizing mask according to claim 5, wherein the mask overlay marks are formed on the separate transparent substrates so as to face each other with an air layer interposed therebetween. 8. The polarization mask according to claim 4, wherein the transparent portion A and the substantially light-shielding portion B are formed on the same surface of the same transparent substrate. 9. The polarizing mask according to claim 4, wherein the portion C which completely shields the illumination light is present only near the portion B which substantially shields the illumination light. 10. A tangential direction of an edge of a pattern of a polarization mask which imparts a polarization characteristic depending on a direction of a pattern on a mask to an illumination light passing through the pattern and the illumination light. In the polarization mask in which the polarization directions of the light transmitted through the pattern are substantially parallel or substantially orthogonal, the means for imparting the polarization characteristic comprises a micro slit structure. 11. The polarization mask according to claim 10, wherein the minute slit structure has a structure in which a fine single line or a plurality of fine lines are formed along a line of an edge of the pattern transmitting portion. 12. The polarization mask according to claim 11, wherein the fine single line or fine lines of the fine slit structure are conductive. 13. The polarization mask according to claim 12, wherein the width of the opening of the minute slit is about ½ or less of the exposure wavelength λ. 14. The fine line or fine lines of the fine slit structure are present in the mask.
The polarizing mask according to 1. 15. A tangential direction of an edge of a pattern of a polarizing mask which imparts pattern-dependent polarization characteristics for imparting polarization characteristics depending on a direction of a pattern on a mask to illumination light passing through the pattern and the illumination light. In the method for manufacturing a polarization mask in which the polarization direction of light transmitted through the pattern is substantially parallel or substantially orthogonal, the means for imparting the polarization characteristics is to use a focused ion beam to form a single fine groove in a transparent film on a transparent substrate. Alternatively, a method for manufacturing a polarization mask is obtained by carving a plurality of layers, depositing a conductive material by a sputtering method, and leaving only a single fine groove or a plurality of fine grooves by polishing. 16. 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 the light transmitted through the mask is projected onto an object to be exposed through a projection optical system. In a pattern exposure method of projecting onto a mask and exposing an image from the original pattern, a polarization characteristic according to the direction of the pattern on the mask is imparted to the illumination light transmitted through the pattern.
6. A pattern exposure method using the polarizing mask according to any one of 5 above. 17. The pattern exposure method according to claim 16, wherein the directivity of the illumination light is annular illumination or oblique illumination. 18. The pattern exposure method according to claim 16, wherein the polarization state of the illumination on the pupil of the projection optical system is substantially rotationally symmetric with respect to the center of the pupil when the mask is not provided. 19. The pattern exposure method according to claim 16, wherein a polarizing element or an analyzing element whose polarization state is substantially rotationally symmetrical with respect to the center of the pupil is arranged near the pupil of the projection optical system. 20. 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 illumination light is a pupil of the projection optical system. 21. The passage and the other one does not pass through the pupil.
The pattern exposure method according to the item. 21. The illumination light is ordinary illumination, and its directivity σ
Is 0.5 or more, and the polarization state of the illumination light is substantially rotationally symmetric with respect to the center of the pupil when the mask is not provided. 22. 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 transmission of the mask. In a pattern exposure apparatus including a projection optical system for projecting light onto an object to be exposed, the polarization state of the illumination light on the pupil of the projection optical system is substantially rotationally symmetric with respect to the pupil center in the absence of the mask. A pattern projection exposure apparatus comprising a polarizing means for smoothing. 23. The pattern projection exposure apparatus according to claim 22, wherein the illumination optical system comprises a modified illumination means for realizing annular illumination or oblique illumination. 24. The pattern projection exposure apparatus according to claim 22, wherein the polarization means is effectively included in the illumination optical system. 25. The pattern projection exposure apparatus according to claim 22, wherein the polarization means is included in the projection optical system.