JPH07211617A - Pattern formation, mask and projection aligner - Google Patents

Abstract

PURPOSE:To enhance resolution and depth of focus by providing a thin film having transmittinity dependent on the incident angle of light between a mask and an illumination optical system when the mask is irradiated with light from a light source through the illumination optical system and a pattern on the mask is projected onto a substrate through a projection lens. CONSTITUTION:When a mask 3 is irradiated with light from a light source 1 through an illumination optical system 2 and a pattern on the mask 3 is projected onto a substrate through a projection lens, an interference filter 13 for increasing the transmittinity relatively to the mask 3 is disposed between the mask 3 and the illumination optical system 2. The interference filter 13 has transmittinity dependent on the incident angle theta being set such that the transmittinity for vertical incident light is decreased. The angular drstribution of light illuminating the mask 3 is controlled variously and the spatial frequency transfer characteristics of the optical system are varied thus enhancing the resolution and increasing the depth of focus. This method allows formation at an LSI having circuit pattern dimensions of about 0.2-0.3mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method for forming a fine pattern of various solid-state devices, a mask used for the same, and a projection exposure apparatus.

[0002]

2. Description of the Related Art In order to improve the degree of integration and operation speed of solid-state elements such as LSI, circuit patterns are becoming finer. At present, a reduction projection exposure method, which is excellent in mass productivity and resolution performance, is widely used for forming these patterns.

FIG. 4 schematically shows an optical system of the reduction projection exposure method. This method irradiates the mask 3 with the light emitted from the effective light source 1 on the secondary light source surface through the illumination optical system 2 to make the mask 3
The pattern is transferred onto the substrate by projecting the above pattern onto the substrate 5 through the projection lens 4.

FIG. 3 (a) schematically shows the principle of image formation by this method. The light incident on the mask 3 is 0 by the mask.
The light is diffracted into the secondary diffracted light 7, the primary diffracted light 8, the secondary diffracted light 9, etc., and these diffracted lights are focused again on the substrate 5 by the projection lens 4 and interfere with each other to form an image. Since the resolution limit of this method is proportional to the exposure wavelength and inversely proportional to the numerical aperture (NA) of the projection lens, the resolution limit has been improved by increasing the NA and shortening the wavelength. But 6
After 4 Mbit DRAM, since the circuit size becomes smaller than the wavelength of light, it has become difficult to improve the resolution by increasing the NA and shortening the wavelength in the related art.

Therefore, various methods have been tried for increasing the resolution by means other than increasing the NA and shortening the wavelength. For example, a modified illumination method is known in which the resolution and the depth of focus are improved by illuminating the mask obliquely. As shown in FIG. 3B, according to this method, even the diffracted light diffracted at a larger angle can pass through the pupil of the projection lens, so that the resolution is improved.

A phase shift method for controlling the phase of light passing through a mask is also known. Among the phase shift methods, the spatial frequency doubling type phase shift method, which inverts the phase between adjacent openings, is extremely effective in improving resolution, but has a drawback that the applied pattern is limited to a periodic pattern or the like. On the other hand, the edge-enhanced phase shift method in which a phase inversion portion having a minute width is provided around the transmission pattern or at the edge portion is characterized in that the applied pattern is not selected.

FIG. 3C shows a state in which the light diffracted by the edge-enhanced phase shift mask 11 forms an image, and the thickness of each diffracted ray represents the intensity of the light. This mask has an effect of emphasizing a high-order diffracted light component or a high spatial frequency component diffracted at a large angle in the light diffracted by the mask, as compared with the conventional method of FIG.

On the other hand, a Fourier transform image of the mask pattern is obtained on the pupil plane 6 of the projection lens, which is the spatial frequency space for the mask as the real space. Therefore, the spatial frequency transfer characteristic of the projection lens can be changed by providing a spatial filter on the pupil plane and modulating the amplitude transmittance. For example, when the high frequency enhancement type pupil filter 12 in which the transmittance of the peripheral portion of the pupil is higher than that of the inside thereof is provided, the high spatial frequency component or the high-order diffracted light passing through the peripheral portion of the pupil is converted into the light passing through the central portion of the pupil. It is relatively emphasized (Fig. 3)
(D)). Therefore, also by this method, the same operation as the edge enhancement type phase shift method can be obtained. On the contrary, when the high-order diffracted light is suppressed, so-called apodization or multi-amplitude imaging (multi-focal point) action provides an effect of increasing the depth of focus. Furthermore, combining the edge-enhanced phase shift method or the pupil filtering method with the modified illumination method,
A greater effect can be obtained.

Regarding the modified illumination method and the high-frequency emphasis type pupil filter, for example, Japanese Journal
Of Applied Physics, Volume 31, 4126
Page to page 4130 (1992) (Japanese Journal
of Applied Physics, Vol.30, pp.4126-413
0 (1992)). Further, regarding various phase shift methods, for example, Japanese Journal of Applied Physics, Volume 30, 299.
Pages 1 to 2997 (1991) (Japanese Journal
of Applied Physics, Vol.30, pp.2991-299
7 (1991)). As for the pupil filtering method, for example, Journal of Vacuum
Science and Technology, B, Vol. 9, No. 6 (1991) (Journal of Vacuum Science and
Technology, Vol. B9, No. 6 (1991)).

[0010]

However, in the modified illumination method as well, there is a problem that the illumination optical system needs to be modified in order to suppress the decrease of the light quantity. Also, a method has been proposed in which the angle of incidence of illumination light on the mask is tilted by providing phase diffraction or the like directly above the mask. However, in this method, a very fine phase diffraction grating has a large area in order to diffract the light. There was a problem that it had to be formed over.

Further, the phase shift method has a problem that a very precise mask technique is required. That is, the phase shifter for controlling the phase must be processed according to the individual pattern on the mask, but especially in the case of the edge enhancement type mask, the lateral dimension of the shifter is much smaller than the pattern dimension on the mask. Therefore, there is a problem that the processing is difficult. On the other hand, the pupil filtering method has a problem that the inside of the projection lens, which is a very precise optical system, needs to be remodeled, although it does not require fine processing such as the phase shift method. In particular, in the above-described high-frequency emphasis type filter, light energy must be removed from the pupil surface by some method in order to reduce the light transmittance at the center of the pupil.
In this case, there is a risk that heat or stray light is generated and the imaging characteristics of the lens are deteriorated.

Further, in the case of the modified illumination method and the pupil filtering method, there is a problem that the effect thereof is common to all patterns on the mask. On the other hand, recent LSI
With the systematization, memory and logic tend to coexist on one chip. In this case, the characteristics of the circuit pattern (such as periodicity) in the memory area and the logic area are different,
Although it is preferable to apply an optimized exposure method to each region, the conventional modified illumination method and pupil filtering method have not been able to meet this requirement.

A first object of the present invention is to improve the resolution and the depth of focus by realizing the same effect as the modified illumination method by a simple method that does not require modification of the illumination optical system or a fine diffraction grating. is there.

A second object of the present invention is to improve the spatial frequency transfer characteristic of an optical system by a simpler method without using a complicated method such as an edge enhancement type phase shift method and a pupil filtering method, and It is to improve the depth of focus.

A third object of the present invention is to provide a pattern forming method, a mask and a projection exposure apparatus which can selectively obtain these effects for a specific area on the mask.

[0016]

The first object is to irradiate a mask with light emitted from a light source through an illumination optical system and project and expose a pattern on the mask onto a substrate through a projection lens. It is achieved by providing a thin film between the mask and the illumination optical system, the light transmittance of which depends on the incident angle of light. At this time, it is preferable that the incident angle dependency is set so that the transmittance with respect to the light which is vertically incident on the mask becomes small. Here, the incident angle dependency can be controlled by the multiple interference effect in the thin film.

The second object can be achieved by providing a thin film between the substrate and the lens or between the projection lens and the mask such that the light transmittance depends on the incident angle of light. At this time, the incident angle dependence of the thin film transmittance is such that the transmittance with respect to the incident angle of the 0th-order diffracted light by the mask becomes small, or conversely, the transmittance becomes low for light incident at a large angle. It can be set variously according to the purpose. Such a thin film may be installed as an interference filter between the substrate and the lens, or can be directly applied onto the resist film on the substrate.

Further, the third object is achieved by providing these thin films selectively with respect to a region corresponding to a specific portion of the mask.

The second or third object is to provide a mask on the surface opposite to the surface on which the light-shielding pattern is formed, or on the entire surface between the light-shielding pattern layer and the mask substrate or in a specific region. This is achieved by providing a thin film having a characteristic that the light transmittance depends on the incident angle of light within the range of the angular distribution of light that illuminates the mask. Further, these purposes are such that, in the projection exposure apparatus, the light transmittance of light is incident on at least one of the substrate and the projection lens, the projection lens and the mask, or the mask and the illumination optical system. This is achieved by providing a thin film interference filter having a characteristic that depends on the angle and making the filter replaceable depending on the mask.

[0020]

In the partially coherent illumination optical system used in the projection exposure method, the mask is generally illuminated with light from various directions. Therefore, in the present invention, as schematically shown in FIG. 1, the interference filter 1 having a relatively large transmittance with respect to light obliquely incident on the mask 3.
3 is provided between the mask 3 and the illumination optical system 2. Thereby, the angular distribution of the illumination light that illuminates the mask can be controlled in various ways.

FIG. 1A schematically shows how the light emitted from various positions a to e in the effective light source 1 illuminates the mask 3 at various angles via the illumination optical system 2. There is. The incident angle dependence of the transmittance of the interference filter 13 is shown in FIG.
As shown in, the transmittance for vertically incident light is set to be small. As shown in FIG. 3B, the modified illumination method improves the resolution and the depth of focus by illuminating the mask obliquely. Therefore, by using the interference filter of FIG. 1, the same effect as the modified illumination method can be obtained.

On the other hand, as shown in FIG. 3, the light diffracted at a large angle passes through the peripheral portion of the pupil and is incident on the resist film at a large angle.

Therefore, in the present invention, as shown in FIG. 2A, an interference filter 14 is provided between the photosensitive resist film 10 coated on the substrate 5 and the projection lens 4. here,
As shown in FIG. 2B, the thin film interference filter 14 suppresses 0th-order diffracted light and low spatial frequency components that are incident at an angle close to vertical to the filter. Higher-order diffracted light having a relatively large angle and high spatial frequency components are relatively emphasized. Further, these interfere with each other in the resist to form an image intensity distribution, and a photochemical reaction corresponding to this distribution is induced in the resist.

As shown in FIGS. 3 (c) and 3 (d), the edge-enhanced phase shift mask and the pupil filter are arranged so that the intensity of the diffracted light by the mask is changed according to the diffraction angle or the diffraction order. Improve the spatial frequency transfer characteristics of the system. Therefore, by using the interference filter of FIG.
The spatial frequency transfer characteristic of the optical system can be improved without using an edge enhancement type phase shift mask or a pupil filter. It is clear from FIG. 2 that the same effect can be obtained when the interference filter is provided directly below the mask. However, since the angular distribution of the diffracted light differs between the mask side and the substrate side depending on the magnification of the lens, this point needs to be taken into consideration. The interference filter may be provided on both the substrate side and the mask side.

As described above, by providing a film whose transmittance depends on the incident angle of light in the optical path, it is possible to control the mask incident angle distribution of the mask illumination light just above the mask, or just below the mask or to the resist film. By changing the intensity of the diffracted light directly above depending on the diffraction angle or the diffraction order, the imaging characteristics of the exposure optical system are improved, and the resolution and the depth of focus are improved. The incident angle dependence of the transmittance can be variously controlled by utilizing the multiple interference effect in the thin film.

Since the multiple interference filter can be provided directly above or below the mask, or directly above the substrate which is conjugate with the mask, it can be provided immediately above or below a specific region on the mask, or in a region conjugate with the above region on the substrate. It can be selectively provided only directly above. By doing so, the various effects described above can be applied only to the pattern in a specific region on the mask.

Further, a larger effect can be obtained by combining the modified illumination effect when the multiple interference filter is provided directly above the mask with the high spatial frequency enhancement effect or the multiple focus effect when provided just below the mask or immediately above the substrate. be able to.

When the multiple interference filter is provided directly on the mask pattern, the interference film is formed on the mask and
The resolution and the depth of focus can be further increased by using this mask as a so-called halftone phase shift mask in which the light shielding portion is provided with a slight transmittance and the transmitted light phase is inverted from the phase of the mask opening portion. With such a mask, simply changing the composition of the film deposited on the mask,
The effect of the annular illumination method and the effect of improving the spatial frequency characteristics are realized at the same time without complicated mask processing such as resolution of the optical system and phase shifter.

On the other hand, when the multiple interference filter is provided directly below the mask or directly above the substrate, the angle of incidence of the 0th-order diffracted light has a certain spread due to the shape of the effective light source, and therefore the angular dependence of the filter transmittance depends on the shape of the effective light source. It is preferable to change. For example, when emphasizing the high spatial frequency component of the diffracted light, it is desirable to set the transmittance so that it becomes minimum near the center of the incident light angle distribution of the 0th-order diffracted light. Further, in FIG. 2, the edge enhancement effect for enhancing the high-order diffracted light has been described for the sake of simplicity, but it is conceivable that the angular dependence of the transmittance may be set variously according to the purpose. For example, when high-order diffracted light is suppressed, which is the opposite of that shown in FIG. 2, so-called apodization or multi-amplitude imaging (multi-focal point) action provides an effect such as increasing the depth of focus. In this case, the incident angle θ (the angle between the normal direction of the thin film surface and the incident ray) is 0.7 · asin (NA) <θ <asin (NA)
It is preferable that the transmittance is set to be a decreasing function of the incident angle θ in the range of (sin is an inverse sin function). or,
It is also possible to simultaneously achieve the edge enhancement effect and the multi-amplitude imaging effect. In any case, the depth of focus and the resolution can be further improved by combining with oblique incidence illumination such as annular illumination.

When the multiple interference filter is provided directly below the mask or directly above the substrate, the filter is inserted in the optical path of the projection optical system. Therefore, this may cause the phase of the transmitted light to change depending on the incident angle of the filter to cause aberration. Therefore, it is preferable to design the multiple interference filter so that the phase change is as small as possible. Further, it is desirable to perform aberration correction in advance if necessary. As the aberration correction method, a pupil aberration correction filter or the like can be used in addition to the lens design stage. On the other hand, it is possible to positively use the phase change by the multiple interference filter. That is, by inverting the phase of the high spatial frequency component with the phase of the low spatial frequency component, a multifocal effect or a defocus aberration suppressing effect can be obtained.

Although the light reflection at the interface depends on the polarization state of the incident light, since the light used for exposure is generally in the non-polarization state, it interferes with S-polarized light (electric field vibration component perpendicular to the incident surface) and P. The effect of interference of polarized light (parallel electric field vibration component on the plane of incidence) is averaged. However, in general, the use of S-polarized light provides a larger interference effect. Therefore, in the case where the mask pattern is a periodic pattern extending in a specific direction, a larger effect can be obtained by using S-polarized light in which the electric field vibrates in a direction perpendicular to the pattern repeating direction. This is also preferable from the viewpoint of preventing a decrease in image contrast due to a component of the electric field in the optical axis direction caused by P-polarized light, which becomes a problem when the NA is increased.

Further, instead of providing an interference filter directly on the resist film, an appropriate thin film may be directly applied on the resist. In the case of an interference filter, a strong multiple interference effect can be obtained because the optical conditions can be controlled in a wide range, whereas when the interference film is applied on the resist, the optical conditions such as the refractive index are limited due to material restrictions. However, it is attractive in that it can be realized by a simple process method.

[0033]

EXAMPLE 1 Using an i-line reduction projection exposure apparatus with a numerical aperture of 0.5, various patterns are formed on a novolac-based positive resist film (film thickness 1 μm) coated on a Si substrate. The mask was transferred under various defocus conditions. Here, the interference filter having the incident angle dependency of the transmittance shown in FIG. 5 was provided immediately above the mask. As a result, 0.30μ
An mL / S pattern could be formed with a focal depth of 1.3 μm.
For comparison, a similar experiment was conducted without providing a filter, and the depth of focus was only 1 μm for a 0.4 μmL / S pattern, confirming the effect of the present invention.

The filter film may be directly formed on the surface of the mask opposite to the pattern surface by vapor deposition. As the material of the filter, various materials such as BN, SiC, SiCN, SiO ₂ , artificial diamond, or a suitable metal thin film and a combination thereof can be used. In addition, the use of the dielectric multilayer film allows various settings of the angular dependence of the transmittance. Also, the wavelength of the exposure device, the numerical aperture,
The resist process used and the like are not limited to those shown in the above embodiment.

(Embodiment 2) In a mask for a wiring layer of a memory having a periodic wiring pattern on a memory mat and a random wiring pattern on a peripheral circuit portion as schematically shown in FIG. The multiple interference film 21 having the same characteristics as in Example 1 was formed only in the region corresponding to the memory mat portion on the mask substrate 20, and the light intensity adjusting film 22 was formed in the peripheral circuit region. A protective film 23 was formed thereon, and a normal light-shielding pattern 24 was further formed thereon. The light intensity adjusting film is provided to cancel the attenuation of the light intensity due to the multiple interference film 21, and may be omitted. Further, a protective film is not always necessary.

FIG. 6B shows a sectional view of the mask of this embodiment. According to this example, good pattern formation could be performed on both the memory mat and the peripheral circuit section.

(Third Embodiment) In the second embodiment, the light-shielding pattern of the memory mat portion is a semi-transparent film having a transmittance of 4%, and the phase of the transmitted light is inverted from the phase of the transmitted light of the mask opening. A so-called halftone phase shift mask was used. As a result, the resolution of the memory mat portion is further improved.

(Embodiment 4) In Embodiment 2, the memory mat portion is composed of a spatial frequency doubling type (periodic) phase shift mask, and the multiple interference film 21 has the same characteristics as those used in Embodiment 1. Instead, the transmittance for light that is perpendicularly incident on the mask pattern is increased. As a result, it was possible to obtain extremely high resolution and large depth of focus in the memory mat portion, similar to the case where the spatial frequency doubling type phase shift mask is used under high coherent illumination. On the other hand, in the peripheral circuit section, the conventional transfer characteristics were maintained. Further, the peripheral circuit section may be further provided with a multiple interference film having the characteristics of the first embodiment. As a result, the effect of annular illumination can be obtained in the peripheral circuit section.

(Example 5) Using the same exposure apparatus and resist as in Example 1, the same pattern transfer was performed. Here, an interference filter having a SiN membrane structure was provided between the substrate and the lens. Membrane thickness is 1.5
Three types of 1.7 and 2 μm (filters A, B and C respectively) were prepared.

FIG. 7 shows the incident angle dependence of the transmittance of these interference filters. The refractive index of the SiN film is about 2.
It was 2. These membrane filters can be manufactured in exactly the same manner as in the case of a mask for X-ray lithography.

Illumination conditions were set to annular illumination with σ of 0.6 to 0.7, and a filter B was used to transfer a periodic line-and-space (L / S) pattern. As a result, 0.28μ
m pattern could be formed with a focal depth of 1.7 μm. In addition, the illumination condition was returned to normal illumination having σ of 0.5, and the filter used in Example 1 was provided directly above the mask instead of the normal illumination.
Almost the same effect was obtained. On the other hand, when the normal illumination of σ = 0.5 and the filter A were used, 0.42 μm hole pattern could be formed within the depth of focus of about 2.5 μm. The cross-sectional shape of the resist pattern was also good. Next, when the NA was changed to 0.45 and the same pattern transfer was performed using the filter C, the same effect was observed.

For comparison, a similar experiment was conducted without providing a filter, and only 1 μm was obtained for an L / S pattern having a depth of focus of 0.4 μm, confirming the effect of the present invention. . Although the membrane-structured filter is used in this embodiment, a thin film may be deposited on an optically flat quartz substrate. Also, a pellicle film can be used for the substrate.

(Embodiment 6) As shown in FIG. 8, when a mask 32 including a memory area 30 composed of a periodic pattern and a logic area 31 composed of a random pattern is exposed, it is formed directly above and directly below the mask. , The multiple interference films 33 and 3 are formed only in the area corresponding to the memory area on the mask.
4 was provided. Here, the interference filter 33 emphasizes the light that illuminates the mask obliquely as in the first embodiment, and the interference filter 34 emphasizes the light diffracted by the mask at a large angle as in the third embodiment. This allows
Conventional exposure is performed on the logic area, while substantially annular illumination and high spatial frequency enhancement are performed on the memory area. According to this embodiment, it was possible to achieve both high resolution and large depth of focus for the memory area and good pattern fidelity for the logic area.

As in the case of the fourth embodiment, when the memory area is a spatial frequency doubling type (periodic) phase shift mask and the interference film 33 is changed to one that emphasizes vertical illumination light,
The resolution of the memory area can be further increased (in this case, the interference film 34 is not necessary). This makes it possible to reduce the design rule of the memory area and reduce the area of the LSI chip.

(Embodiment 7) A perfluoroalkyl polyether is coated (film thickness 100 nm) on a novolac type positive resist film (film thickness 1 μm) coated on a Si substrate.
Then, using this i-line reduction projection exposure apparatus with a numerical aperture of 0.5, masks containing various patterns were transferred under various defocus conditions. The refractive indices of the resist and perfluoroalkyl polyether were about 1.7 and 1.29, respectively. According to this example, a 0.42 μm hole pattern could be formed on the entire surface of the exposure region with a dimensional accuracy of ± 10% within a depth of focus of about 1.5 μm. The cross-sectional shape of the resist pattern was also good. For comparison, the same experiment was performed without applying a thin film, and the depth of focus was 0.4 μm.
Only 1 μm was obtained with respect to the pattern No., confirming the effect of the present invention.

[0046]

According to the present invention, when the light emitted from the light source is applied to the mask through the illumination optical system and the pattern on the mask is projected and exposed on the substrate through the projection lens to form the pattern. By providing a thin film in the optical path of the exposure optical system whose transmittance depends on the incident angle of light, the spatial frequency transmission of the optical system can be performed without using the modified illumination method, phase shift method, pupil filtering method, etc. The characteristics can be changed to improve the resolution and increase the depth of focus. This makes it possible to form an LSI having a circuit pattern size of 0.2 to 0.3 μm by using optical lithography.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention.

FIG. 2 is an explanatory diagram of the principle of the present invention.

FIG. 3 is an explanatory view showing the operation of the conventional method.

FIG. 4 is an explanatory diagram showing a configuration of a conventional device.

FIG. 5 is a characteristic diagram of an example of the present invention.

FIG. 6 is an explanatory diagram of a second embodiment of the present invention.

FIG. 7 is a characteristic diagram of the second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a third embodiment of the present invention.

[Explanation of symbols]

1 ... Effective light source, 2 ... Illumination optical system, 3 ... Mask, 13 ... Thin film interference filter.

Claims (14)

[Claims] 1. A method of forming a pattern by irradiating a mask with light emitted from a light source through an illumination optical system and projecting and exposing the pattern on the mask onto a substrate through a projection lens, the method comprising: A pattern forming method, characterized in that a thin film having a characteristic that light transmittance depends on an incident angle of light is provided in the optical path of the light. 2. The pattern forming method according to claim 1, wherein the thin film having the characteristic that the light transmittance depends on the incident angle of light is provided between the mask and the illumination optical system. 3. The thin film according to claim 1, wherein the light transmittance has a characteristic that depends on the incident angle of light, at least between the substrate and the projection lens or between the projection lens and the mask. A pattern forming method provided on either side. 4. The pattern forming method according to claim 2, wherein the incident angle dependence of the light transmittance of the thin film is set such that the light transmittance of light perpendicularly incident on the mask becomes small. 5. The pattern forming method according to claim 3, wherein the incident angle dependence of the light transmittance of the thin film is set so that the transmittance with respect to the incident angle of the 0th order diffracted light by the mask becomes small. 6. The light transmittance of the thin film according to claim 3, wherein an incident angle θ is 0.7 · asin (NA) <θ <asin (N
A) A pattern forming method which is a decreasing function of the incident angle θ within a range of (where asin is an inverse sin function and NA is the numerical aperture of the projection lens). 7. The pattern forming method according to claim 1, wherein the thin film is selectively provided in a region corresponding to a specific portion of the mask. 8. The pattern forming method according to claim 1, wherein the incident angle dependence of the light transmittance of the thin film is controlled by a multiple interference effect in the thin film. 9. The pattern forming method according to claim 2, wherein the thin film is a film deposited directly on the mask. 10. The pattern forming method according to claim 3, wherein the thin film is a coating film coated on a resist on the surface of the substrate. 11. A mask used when irradiating light emitted from a light source onto a mask through an illumination optical system and projecting and exposing a pattern on the mask onto a substrate through a projection lens. On the surface opposite to the surface on which the light-shielding pattern is formed, or on the entire surface or a specific region between the light-shielding pattern layer and the mask substrate, the transmittance of which is perpendicular to the light obliquely incident on the mask. A mask provided with a thin film having a property of becoming smaller with respect to light. 12. The light-shielding pattern according to claim 11, wherein the light-shielding pattern has a transmittance of 2% to 10%, and the phase of light transmitted through the light-shielding pattern is transmitted in a region on the same mask where the light-shielding pattern does not exist. A mask that is almost the opposite of the phase of light. 13. A projection exposure apparatus for irradiating a mask with light emitted from a light source through an illumination optical system and projecting and exposing a pattern on the mask onto a substrate through a projection lens, the mask and the mask. A thin film interference filter having a characteristic that the light transmittance depends on the incident angle of light is provided in at least one of the illumination optical system, the projection lens and the mask, or the substrate and the projection lens. A projection exposure apparatus, which is provided. 14. The projection exposure apparatus according to claim 13, wherein the thin film interference filter is replaceable according to the mask.