JP2000077325A - Exposure method and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure method and an aligner for obtaining a high- resolution pattern in a desired shape, through double exposure by using a pair of masks including phase shifting regions with different phase shift effects. SOLUTION: A first exposure for exposing a resist through a first mask with a shading part and a non-shading part, and a second exposure for exposing the resist through a second mask with a shading part and a non-shading part are provided. Each non-shading part of the first mask and the second mask is the same pattern in shape, and during these exposing steps the resist is not developed. The first mask is so constituted that a phase difference in odd- number times π is applied substantially to light through adjoining regions in at least a first direction at the non-shading parts with the shading part in between, when the light is transmitted through these regions. The second mask is so constituted that a phase difference of odd-number times π is applied substantially to light through adjoining regions in at least a second direction other than the first direction at the non-shading parts with the shading part in between when the light is transmitted through these regions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposing method and an exposing apparatus, and more particularly, to exposing a photosensitive substrate with a fine circuit pattern, for example, a semiconductor chip such as an IC or LSI, a display element such as a liquid crystal panel, a magnetic head, and the like. It is suitable for use in the manufacture of various devices such as a detection device and an imaging device such as a CCD.

[0002]

2. Description of the Related Art Conventionally, when devices such as ICs, LSIs, and liquid crystal panels are manufactured using photolithography technology, circuits formed on the surface of a photomask or reticle (hereinafter, referred to as "mask"). A projection exposure method and a projection exposure method in which a pattern is projected onto a photosensitive substrate such as a silicon wafer or a glass plate (hereinafter, referred to as a “wafer”) coated with a photoresist by a projection optical system and transferred (exposed) there. The device is being used.

In recent years, in response to the higher integration of the above devices, there has been a demand for a finer pattern, ie, a higher resolution, to be transferred to a wafer and a larger area for one chip on the wafer. Therefore, even in the above-described projection exposure method and projection exposure apparatus that form the center of microfabrication technology for wafers,
Image (circuit pattern image) with dimensions (line width) of 0.5 μm or less
In order to form an image over a wide range, the resolution is increased and the exposure area is increased.

FIG. 39 shows a schematic view of a conventional projection exposure apparatus. In FIG. 39, 191 is an excimer laser as a light source for exposure to far ultraviolet rays, 192 is an illumination optical system, 193 is illumination light emitted from the illumination optical system 192, 194 is a mask, 1
Reference numeral 95 denotes object-side exposure light that exits the mask 194 and enters the projection optical system 196. Reference numeral 196 denotes a reduction projection optical system.
Denotes image-side exposure light that exits the projection optical system 196 and enters the substrate 198, 198 denotes a wafer that is a photosensitive substrate, and 199 denotes a substrate stage that holds the photosensitive substrate.

[0005] The laser light emitted from the excimer laser 191 is guided to the illumination optical system 192 by the routing optical systems (190a, 190b), and the illumination optical system 192 provides a predetermined light intensity distribution, light distribution, and opening angle (Sekiguchi). The mask 19 is adjusted so as to have the illumination light 193 having several NA) or the like.
Light 4 On the mask 194, a pattern having a size obtained by reciprocally multiplying (for example, 2 times, 4 times, or 5 times) the fine pattern formed on the wafer 198 by a projection magnification of the projection optical system 196 is formed on a quartz substrate by chrome or the like. And illumination light 1
93 is transmitted and diffracted by the fine pattern of the mask 194, and becomes the object side exposure light 195. The projection optical system 196 includes:
The object-side exposure light 195 is converted into image-side exposure light 197 that forms a fine pattern of the mask 194 on the wafer 198 at the above-described projection magnification and with sufficiently small aberration. Image side exposure light 19
Numeral 7 converges on the wafer 198 at a predetermined numerical aperture NA (= Sin (θ)) as shown in the enlarged view at the bottom of FIG. 39, and forms an image of a fine pattern on the wafer 198. The substrate stage 199 has a plurality of different areas (shot areas: areas to be one or more chips) of the wafer 198.
When sequentially forming a fine pattern, the wafer 19 is moved stepwise along the image plane of the projection optical system.
8 with respect to the projection optical system 196.

A projection exposure apparatus using the above-described excimer laser as a light source has a high projection resolution, but it is technically difficult to form a pattern image of, for example, 0.15 μm or less.

The projection optical system 196 is used for exposure (light used for exposure).
There is a resolution limit due to the trade-off between wavelength-dependent optical resolution and depth of focus. The resolution R and the depth of focus DOF of the projection exposure apparatus are expressed by the following Rayleigh formulas (1) and (2).

R = k ₁ = (λ / NA) ‥‥‥ (1) DOF = k ₂ = (λ / NA ² ) ‥‥‥ (2) where λ is an exposure wavelength, and NA is a projection optical system 196. The numerical apertures k ₁ and k ₂ on the image side representing the brightness of the wafer are constants determined by the development process characteristics of the wafer 198 and the like.
The value is about 0.7. From the equations (1) and (2), it is apparent that the numerical aperture N
There is "higher NA" to increase A. However, in actual exposure, the depth of focus DOF of the projection optical system 196 needs to be set to a certain value or more, so that it is difficult to increase the NA to a certain value or more. It is understood that "short wavelength" for reducing the wavelength λ is required.

However, as the exposure wavelength becomes shorter, a serious problem arises. It is the projection optical system 196
Is that the glass material of the lens that constitutes is lost. The transmittance of most glass materials is close to 0 in the deep ultraviolet region,
Using a special manufacturing method for exposure equipment (exposure wavelength about 248
nm), fused quartz exists as a glass material.
The transmittance of the fused quartz also sharply decreases for an exposure wavelength of 193 nm or less. It is very difficult to develop a practical glass material in a region having an exposure wavelength of 150 nm or less corresponding to a fine pattern having a line width of 0.15 μm or less. In addition, the glass material used in the deep ultraviolet region must satisfy various conditions such as durability, uniformity of refractive index, optical distortion, workability, etc. in addition to transmittance. Existence is at stake.

Recently, a glass material such as CaF ₂ or MgF ₂ having a wavelength of about 150 nm and a good transmittance with a certain degree of transmittance has been studied, but the exposure wavelength is not long.

As described above, in the conventional projection exposure method and projection exposure apparatus, it is necessary to shorten the exposure wavelength to about 150 nm or less in order to form a pattern having a line width of 0.15 μm or less on a wafer. On the other hand, at present, there is no practical glass material in this wavelength region, so that a pattern having a line width of 0.15 μm or less cannot be formed on the wafer.

In such a background, in a photolithography technique for obtaining a miniaturized semiconductor device, a phase shift technique has attracted attention in order to further improve its resolution. The phase shift technique is to impart a phase difference to light transmitted through a mask, thereby improving a light intensity profile.

The conventional phase shift technique is disclosed in Japanese Patent Application Laid-Open No. 58-173744, MARCD. LEVENSON et al.
roving Resolutionin Photolithography with a Phase-
Shifting Mask ”IEEE TRANSACTIONS ON ELECTRON DEVIC
ES.Vol.ED-29 No.12, DECEMBER 1982, P1828 ~ 1836, MARC D.LEVENSON et al. &Quot; The Phase-Shifting Ma
skII: Imaging Simulations and Submicrometer Resist
Exposures ”, Vol.ED-31, No.6, JUNE1984, P753-763
There is a description.

Japanese Patent Publication No. Sho 62-50811 has a predetermined pattern formed of a transparent portion and an opaque portion.
A phase shift mask is disclosed in which a phase member is provided on at least one of the transparent portions on both sides sandwiching the opaque portion, and a phase difference is generated between the transparent portions on both sides.

An example of a phase shift technique known in the art, which is called a Levenson type, will be described with reference to FIG. 40 as follows.

For example, when forming a line-and-space pattern on a wafer, a usual conventional mask is:
As shown in FIG. 40A, a light-shielding portion 10 is formed on a transparent substrate 1 such as a quartz substrate using a light-shielding material such as Cr (chromium), other metals, and metal oxides. An exposure mask is formed by forming a repetitive pattern of AND spaces. The intensity distribution of the light transmitted through the exposure mask is ideally zero at the light-shielding portion 10 and at other portions (transmission portions 12a and 12b) as indicated by reference numeral A1 in FIG. To Penetrate.

Considering one transmissive portion 12a, the transmitted light given to the material to be exposed is, as shown by A2 in FIG. It becomes an intensity distribution. Transmitted light A toward the transmission section 12b
2 'is indicated by a dashed line. When the light from each of the transmission portions 12a and 12b is combined, the light intensity distribution loses sharpness as shown by A3, and an image is blurred due to light diffraction. As a result, a sharp exposure cannot be achieved. In contrast,
As shown in FIG. 40B, every other phase shift portion 11a (a material such as SiO ₂ or resist is used as a shifter) is provided on the light transmission portions 12a and 12b of the above-described repeated pattern. Is provided, blurring of an image due to light diffraction is canceled by phase inversion, a sharp image is transferred, and resolution and depth of focus are improved.

That is, as shown in FIG. 40 (b), when the phase shift portion 11a is formed in one of the transmission portions 12a, if it gives a phase shift of, for example, 180 °,
The light that has passed through the phase shift unit 11a is inverted as indicated by reference numeral B1. Since the light from the transmission part 12b adjacent thereto does not pass through the phase shift part 11a, such inversion does not occur. In the light applied to the material to be exposed, the light whose phase is inverted cancels each other at the position indicated by B2 in the figure at the bottom of the light intensity distribution. As shown by B3 in b), a sharp ideal shape is obtained.

In the above case, it is most advantageous to invert the phases by 180 ° with respect to each other in order to ensure this effect most.

[0020]

(Equation 1)

(N is the refractive index of the material forming the phase shift portion,
λ is the exposure wavelength) and the phase shift portion 1 is formed with a film thickness D.
1a is provided.

The above-described phase shift mask that shifts the phase of light passing through the adjacent light transmitting portion (ideally, inverts by 180 °) is called a spatial frequency modulation type (or Levenson type). . In addition, there are various types of phase shift masks such as an edge enhancement type and a light-shielding effect enhancement type, and among them, those formed without a light-shielding portion (such as a chromeless type). However, in each case, at least a part of the portion that transmits the exposure light is provided with a phase shift portion that shifts the phase of the light transmitted therethrough to the light transmitted therethrough.

As a multiple exposure method using two phase shift masks, JP-A-6-83032 discloses a first phase shift mask in which light transmitting portions and phase shift portions are alternately formed, The phase shift mask uses a second phase shift mask formed by inverting the positions of the light transmitting portion and the phase shift portion, and performs exposure using the first phase shift mask and light exposure using the second phase shift mask. Exposure is shown.

In Japanese Patent Application Laid-Open No. 7-50243, a phase shifter provided at a predetermined position in a light transmitting area of a mask having a plurality of patterns formed at intervals of about the exposure wavelength or shorter is used to reduce the phase difference in transmitted light. An exposure method of causing a projection image of the pattern to be exposed on a sample, wherein at least one continuous pattern formed by the exposure has a boundary of phase inversion in transmitted light that has passed through the light transmission region. An exposure method is disclosed in which a pattern portion to be generated and another pattern portion are formed by being divided into different masks, and exposure is performed by matching the relative positions of the two masks.

[0025]

However, the circuit pattern of the integrated circuit to be transferred to the semiconductor wafer is actually provided in a complicated manner, and is not a structure in which the pattern is simply drawn vertically and horizontally. Therefore, in the multiple exposure using the conventional phase shift mask described above, for example, FIG.
In a case where there are a plurality of patterns in a closed pattern as shown in FIG. 1 or a pattern including a U-shaped pattern as shown in FIG. 42, effective exposure cannot always be performed.

An object of the present invention is to provide a mask, an exposure method, and an exposure apparatus capable of performing effective exposure using a phase shift mask even for a pattern having a complicated shape.

[0027]

SUMMARY OF THE INVENTION A mask of the present invention is a set of masks used for exposing a substrate to be exposed in a desired pattern by multiple exposure, and includes a phase shift region having mutually different phase shift effects. Are first and second masks formed in a desired pattern.

In particular, the phase shift regions of the first and second masks have a phase shift of 180 degrees as compared with a light transmitting portion that is not the phase shift region.

The first mask sets a phase shift region so as to resolve fine lines in one direction, and the second mask resolves fine lines in another direction orthogonal to the one direction. The phase shift area is set as follows.

The pattern on the mask has a wavelength of 250 nm.
Exposure is set to the following light. And so on.

The exposure method of the present invention is characterized in that multiple exposure is performed using the first and second masks. Here, “multiple exposure” refers to a plurality of exposures in which the resist is not developed between exposures of the same area.

The exposure apparatus according to the present invention is characterized in that it has an exposure mode for performing multiple exposure using the first and second masks.

A device manufacturing method according to the present invention is characterized in that after exposing a device pattern on a wafer surface by the above-described exposure method, the wafer is manufactured through a developing process.

Next, the constituent features of the present invention will be described.

According to a first aspect of the present invention, there is provided an exposure method for exposing a resist with a pattern, the first exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion. And exposing the resist through a second mask having a portion and a non-light-shielding portion.
The shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern, and the first and second exposures are performed in this order or the reverse order. Alternatively, when the steps are performed simultaneously and sequentially, the development of the resist is not performed between the two exposures, and the first mask is adjacent to at least the first direction across the light shielding part of the non-light shielding part. The matching predetermined region is configured to give a phase difference of substantially an odd multiple of π to light propagating through each region, and the second mask has at least the first mask with the light-shielding portion of the non-light-shielding portion interposed therebetween. Is characterized in that predetermined regions adjacent to each other along a second direction different from the above direction provide a phase difference of substantially an odd multiple of π between light propagating in each region.

According to a second aspect of the present invention, in the first aspect of the present invention, the first mask includes a predetermined region adjacent to the non-light-shielding portion along the second direction with the light-shielding portion interposed therebetween. It is characterized in that it is configured to give a phase difference of substantially π between propagating lights.

According to a third aspect of the present invention, in the second aspect of the present invention, the second mask includes a predetermined region adjacent to the non-light-shielding portion along the first direction across the light-shielding portion. It is characterized in that it is configured to give a phase difference of substantially π between propagating lights.

According to a fourth aspect of the present invention, in the first aspect, the first direction and the second direction are orthogonal to each other.

According to a fifth aspect of the present invention, there is provided an exposure method for exposing a resist with a pattern, the first exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion. Second having a light-shielding part and a non-light-shielding part
A second exposure for exposing the resist through the mask, wherein the shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern. The same, the first and second exposures are performed in this order or the reverse order or simultaneously, and when performed sequentially, the resist is not developed between the two exposures, and the first mask is A phase boundary along the first direction is formed in the non-light-shielding portion, and predetermined regions adjacent to each other across the boundary provide a phase difference substantially odd multiple of π to light propagating through each region. In the second mask, a phase boundary is formed in the non-light-shielding portion along a second direction different from the first direction, and a predetermined region adjacent to the boundary sandwiches each region. Be configured to provide a phase difference of substantially π odd times between propagating lights It is characterized by.

According to a sixth aspect of the present invention, in the fifth aspect, the first direction and the second direction are orthogonal to each other.

According to a seventh aspect of the present invention, there is provided an exposure method for exposing a resist with a pattern, the first exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion. And exposing the resist through a second mask having a portion and a non-light-shielding portion.
The shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern, and the first and second exposures are performed in this order or the reverse order. Or, when performed simultaneously and sequentially, the development of the resist is not performed between the two exposures, and the first mask is provided along at least the first direction with the light-shielding portion of the non-light-shielding portion interposed therebetween. Adjacent predetermined areas give a phase difference substantially odd multiples of π to light propagating in each area, and a phase boundary is formed in the non-light-shielding portion along a third direction. The matching predetermined region is configured to give a phase difference of substantially an odd multiple of π to light propagating in each region, and the second mask has at least the first mask with the light-shielding portion of the non-light-shielding portion interposed therebetween. The predetermined areas adjacent to each other along the second direction different from the first direction are Substantially π between the light propagating through the region
And a third phase difference within the non-light-shielding portion.
A boundary is formed along a fourth direction different from the above direction, and predetermined regions adjacent to each other across the boundary provide a phase difference substantially odd multiple of π between light propagating through each region. It is characterized by having such a configuration.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the first mask is formed such that predetermined regions adjacent to each other in the second direction across the light shielding portion in the non-light shielding portion are each region. It is characterized in that it is configured to give a phase difference of substantially an odd multiple of π between propagating lights.

According to a ninth aspect of the present invention, in the seventh aspect of the present invention, the second mask includes a predetermined region adjacent to the non-light-shielding portion along the first direction across the light-shielding portion. It is characterized in that it is configured to give a phase difference of substantially an odd multiple of π between propagating lights.

According to a tenth aspect of the present invention, in the seventh aspect, the first direction and the second direction are orthogonal to each other.

An eleventh invention is characterized in that, in the seventh invention, the third direction and the fourth direction are orthogonal to each other.

According to a twelfth aspect of the present invention, in the seventh aspect, the first direction and the third direction are orthogonal to each other.

According to a thirteenth aspect, in the seventh aspect, the second direction and the fourth direction are orthogonal to each other.

According to a fourteenth aspect of the present invention, there is provided an exposure method for exposing a resist with a pattern, the first exposing the resist through a first mask having a light-shielding part and a non-light-shielding part. Exposing the resist through a second mask having a portion and a non-light-shielding portion, wherein the shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask Is substantially the same as the shape of the pattern,
The first and second exposures are performed in this order or the reverse order or simultaneously, and when performed sequentially, the resist is not developed between the two exposures, and the first mask is a part of the pattern. Gives an odd-numbered phase difference of π between light propagating in different regions of the non-light-shielding portion so that the resist is exposed to light, and the second mask has another part of the pattern formed by the resist. In this case, a phase difference of an odd multiple of π is given between lights propagating in different areas of the non-light-shielding portion so as to be exposed to light.

According to a fifteenth aspect, in the fourteenth aspect, a part of the pattern of the first mask and the second
Another part of the mask pattern is characterized in that it includes a common part when projected onto a resist.

An exposure apparatus according to a sixteenth aspect of the present invention has a double exposure mode for executing the exposure method according to any one of the first to fifteenth aspects.

According to a seventeenth aspect of the present invention, there is provided a device manufacturing method including a step of transferring a device pattern onto a wafer by using the exposure method according to any one of the first to fifteenth aspects.

[0052]

BEST MODE FOR CARRYING OUT THE INVENTION The mask, exposure method and exposure apparatus according to this embodiment are designed to perform multiple exposures using a set of masks each having a desired pattern provided with a phase shift region having a phase shift effect different from each other. Features.

A set of masks for this purpose is a Levenson-type phase shift mask, in which the phase shift (phase difference) of light passing through adjacent light transmitting portions is 180 °. Further, as a method of setting mutually different phase shift areas, a mask in which a phase shift area is set so as to resolve vertical fine lines by focusing on a vertical fine pattern, and a fine line in the horizontal direction are used. And a set of masks including a mask in which a phase shift region is set so as to resolve a fine horizontal line. 250 nm as exposure light
Light from an excimer laser having the following wavelengths is used.

In this embodiment, first, a phase shift area is set for a fine pattern in the vertical direction, focusing on an area where a pattern corresponding to the minimum line width of the exposure pattern exists. At this time, a phase shift mask is designed that is good even if the boundary region is lost due to a 180 ° change in phase in the horizontal direction.

Next, a phase shift area is set for a fine pattern in the horizontal direction. As in the case of the vertical direction, it is set so that a fine pattern in the horizontal direction is reproduced.

This time, the phase is 180 ° in the vertical direction.
It is acceptable that the boundary of the pattern is missing due to the change.
In this way, a set of phase shift masks having different phase shift effects are prepared, and the set of masks is sequentially supplied to the projection exposure apparatus to perform double exposure on the same wafer. In the first exposure, an exposure amount distribution of a fine pattern in the vertical direction is formed, and in the horizontal direction, an exposure amount distribution in which a pattern is partially missing or blurred is formed on the surface to be exposed. In the exposure, an exposure amount distribution of a fine pattern in the horizontal direction is superimposed.

In the second exposure, in the vertical direction, an exposure amount distribution in which a pattern is partially missing or blurred is formed. The exposure dose distribution becomes more than a predetermined amount in a fine structure in two exposures, and by setting a threshold value of the resist between the predetermined amount and the exposure amount in an unnecessary blur region, a fine complicated structure is obtained. Has gotten a pattern.

As described above, according to the exposure method of the present invention, when exposing a resist with a pattern, the first exposure for exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion; And a second exposure for exposing the resist through a second mask having a non-light-shielding portion. The shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask It is substantially the same as the shape of the pattern, and the first and second exposures are performed in this order or the reverse order or at the same time, and when sequentially performed, the resist is not developed between the two exposures. Features.

Next, a first embodiment of a mask and an exposure method according to the present invention will be described with reference to FIGS. FIG. 1 is a flowchart showing the exposure method of the present invention. FIG. 1 shows the vertical fine pattern exposure step, the horizontal fine pattern exposure step, and the development step, which constitute the exposure method of the present invention, and the flow thereof. The order of the pattern exposure steps may be the reverse of FIG. 1 or may be simultaneous. When either one of the steps includes a plurality of exposure steps, each step can be performed alternately.

Although there is a step of performing precise alignment between each exposure step, it is not shown here.

In this embodiment, a case is shown in which a desired closed fine pattern as shown in FIG. 2 is exposed. When performing exposure in accordance with the flow of FIG. 1, first, a mask (first mask) in which a phase shift region 31 as shown in FIG. 3 is set so as to resolve a vertical fine line by focusing on a vertical fine pattern 2.) Exposing the wafer as the photosensitive substrate by the first pattern exposure using M1.

At this time, in FIG. 3, the light passing through the phase shift region 32 near the boundary 30 and the light passing through the region 33 that is not the phase shift region are 180 degrees out of phase with each other, so that the light intensities cancel each other. The light intensity becomes 0.
As a result, an exposure amount distribution pattern as shown in FIG. 4 is obtained. The same applies to the following embodiments.

The numbers in FIG. 4 represent the exposure amount, and the black portions indicate the exposure amount of zero.

The first mask M1 in the present embodiment has a predetermined region (SX1) adjacent to at least the first direction X across the light-shielding portions (SX2, SX4) in the non-light-shielding portions (SX1, SX3, SX5). And SX3 or SX3 and SX5) are configured to give a phase difference of substantially an odd multiple of π to light propagating in each region.

Further, the first mask M1 has a non-light-shielding portion (SX2
a, SX4a), a phase boundary 30 is formed along the third direction Ya, and a light that propagates in an area adjacent to the boundary 30 is given an odd-numbered phase difference substantially equal to π. I have.

Next, paying attention to a horizontal fine pattern, a wafer (second mask) having a phase shift region 51 as shown in FIG. 5 is set so as to resolve fine horizontal lines. Is exposed.

Here, when passing through the phase shift area 53,
As described above, the light passing through the region 52 that is not the phase shift region near the boundary 50 has a phase difference of 180 degrees and cancels each other, and the light intensity becomes zero, as described above. By this second pattern exposure, the wafer becomes an exposure amount distribution pattern as shown in FIG.

The second mask M2 includes a non-light-shielding portion (SY
1, SY3), a predetermined region (SY1 and SY3) adjacent at least along a second direction Y different from the first direction X across the light-shielding portion (SY2) is located between the light propagating in each region. The configuration is such that a phase difference substantially equal to an odd multiple of π is given.

The second mask M2 has a non-light-shielding portion (SY2
In (a), a phase boundary 50 along the fourth direction Xa is formed, and the light propagating in the region adjacent to the boundary 50 is given a phase difference substantially an odd multiple of π.

In the present embodiment, the first direction X and the second direction Y are orthogonal, and the third direction Ya and the fourth direction Xa
Are orthogonal, and the first direction (second direction) is orthogonal to the third direction (fourth direction).

Here, the first mask M1 provides a phase difference of an odd multiple of π between lights propagating through the different regions 32 and 33 of the non-light-shielding portion so that a part of the pattern is exposed to the resist. The second mask M2 provides an odd multiple of π of a phase difference between lights propagating through different regions 52 and 53 of the non-light-shielding portion so that another part of the pattern is exposed to the resist. ing.

Here, the portion 32 (33) of the pattern of the first mask M1 and the other portion 53 (52) of the pattern of the second mask M2 include a common portion when projected onto a resist.

The exposure amount distribution on the wafer thus double-exposed is as shown in FIG. When developing such a pattern after exposure, the exposure threshold value Eth of the resist on the photosensitive substrate is usually set between 0 and 2.

FIG. 8 shows a positive resist (hereinafter, referred to as a “positive type”) showing the dependence of the film thickness after development on the amount of exposure and the exposure threshold for the resist on the wafer serving as the photosensitive substrate in this case. And negative resist (hereinafter referred to as "negative resist")
In the case of the positive type, the region exposed with the exposure amount equal to or more than the exposure threshold value Eth is used, and in the case of the negative type, the region is exposed with the exposure amount equal to or less than the exposure threshold value Eth. The unexposed regions have a film thickness of 0 after development.

In this way, a desired resist pattern as shown in FIG. 7B can be obtained. FIG. 9 is a schematic diagram showing a state in which a lithography pattern is formed through the development and etching processes when such exposure is performed, for a negative type and a positive type.

Next, a mask and an exposure method according to the second embodiment of the present invention will be described with reference to FIGS. Figures 10-14
Shows a second embodiment, in which a desired pattern as shown in FIG. 41 is exposed.

First, paying attention to a vertical fine pattern, a mask (first mask M1) in which a phase shift region PH as shown in FIG. 10 is set so as to resolve vertical fine lines.
The wafer is exposed by the first pattern exposure in an exposure distribution pattern as shown in FIG.

Next, paying attention to the horizontal fine pattern, a mask (second mask M2) in which the phase shift area PH as shown in FIG. 12 is set so as to resolve horizontal fine lines.
Is used to expose the wafer with an exposure distribution pattern as shown in FIG. 13 by the second pattern exposure. The exposure is basically the same as in the first embodiment.

The exposure amount distribution on the wafer thus double-exposed is as shown in FIG. Here, if the threshold value of the resist is set in the same manner as in the first embodiment, a desired resist pattern as shown in FIG. 14B can be obtained.

FIG. 15 is an explanatory view of a pattern according to the third embodiment of the present invention, and FIGS. 16 to 20 are explanatory views of a mask and an exposure method of the third embodiment.

In this embodiment, first, paying attention to a horizontal fine pattern, a horizontal fine line is resolved as shown in FIG.
A mask in which a phase shift region PH is set as shown in FIG.
Using the mask M2), the wafer is exposed by the second pattern exposure in the exposure amount distribution pattern as shown in FIG.
In the drawing, the portion where the exposure amount is indicated by a is caused by blurring, and the exposure amount is smaller than 1.

As shown in FIG. 16, the second mask M
2 is a light-shielding portion (S) in a non-light-shielding portion (SY1, SY3).
Y2) and the predetermined regions (SY1, SY) adjacent to each other along at least a second direction Y different from the first direction X across the first direction X
3) is configured to give a phase difference of substantially an odd multiple of π between light propagating in each region.

Next, paying attention to the vertical fine pattern, a mask (first mask M1) in which a phase shift region PH as shown in FIG. 18 is set so as to resolve vertical fine lines.
, The wafer is exposed by a first pattern exposure in an exposure distribution pattern as shown in FIG.

The first mask M1 shown in FIG. 18 has a predetermined area (SX1, SX3) adjacent to the non-light-shielding section (SX1, SX3) along at least the first direction X with the light-shielding section (SX2) interposed therebetween. Are configured to provide a phase difference substantially equal to an odd multiple of π to light propagating in each region.

In the first mask M1 shown in FIG. 18, a phase boundary 30 is formed along the second direction X in the non-light-shielding portion (SX4, SX5), and a predetermined region adjacent to the boundary 30 is formed. The configuration is such that light that propagates through each region is given a phase difference substantially an odd multiple of π.

The second mask M2 shown in FIG. 16 has a phase boundary 50 along the first direction X in the non-light-shielding portion (SY2a).
Is formed, and predetermined regions adjacent to each other with the boundary 50 interposed therebetween provide a phase difference substantially odd multiple of π between light propagating in each region. The exposure dose distribution on the wafer thus double-exposed is as shown in FIG.

If the threshold value of the resist is set between a and 2, a desired resist pattern as shown in FIG. 20B can be obtained.

FIGS. 21 to 25 are explanatory views of a mask and an exposure method according to the fourth embodiment of the present invention, in which the same pattern as that of the third embodiment shown in FIG. 15 is exposed.

First, paying attention to the horizontal fine pattern, a mask (second mask) in which the phase shift region PH is set as shown in FIG. 21 so as to resolve horizontal fine lines is used. The wafer is exposed in the exposure amount distribution pattern as shown in FIG. At this time, the area in which a fine pattern can be formed is increased by partially considering the vertical direction.

Next, paying attention to the vertical fine pattern, using a mask (first mask) in which a phase shift region PH is set as shown in FIG. 23 so as to resolve vertical fine lines, The first pattern exposure exposes the wafer in an exposure distribution pattern as shown in FIG.

The first mask M1 shown in FIG. 23 has a predetermined area (S) adjacent at least along the first direction X across the light-shielding part (SX2) of the non-light-shielding parts (SX1, SX3).
X1, SX3) gives a phase difference of substantially an odd multiple of π to the light propagating in each region, and the non-light-shielding portions (SX4, SX3).
In 5), a boundary 30 of the phase along the third direction Ya is formed, and predetermined regions adjacent to each other across the boundary provide a phase difference substantially odd multiple of π to light propagating in each region. It is composed.

The second mask M2 shown in FIG. 21 is adjacent to the non-light-shielding portion (SY1, SY3) at least along the second direction Y different from the first direction X with the light-shielding portion (SY2) interposed therebetween. The predetermined regions (SY1, SY3) that match each other provide a phase difference of substantially an odd multiple of π between the lights propagating in the respective regions, and the fourth region different from the third direction Ya in the non-light-shielding portion (SY2a). Is formed such that predetermined regions adjacent to each other across the boundary 50 provide a phase difference substantially odd multiple of π between light propagating through each region. ing.

The exposure amount distribution on the wafer thus double-exposed is as shown in FIG. Here, if the threshold value of the resist is set between 0 and 2, a desired resist pattern as shown in FIG. 25B can be obtained.

FIGS. 26 to 30 are explanatory views of a mask and an exposure method according to the fifth embodiment of the present invention. In the present embodiment, FIG.
This is for exposing a pattern such as First,
Focusing on the vertical fine pattern, the first pattern exposure is performed by using a mask (first mask M1) in which a phase shift region PH is set as shown in FIG. 26 so as to resolve vertical fine lines. Exposes the wafer with an exposure distribution pattern as shown in FIG.

Next, paying attention to the horizontal fine pattern, a mask (second mask M2) in which a phase shift area PH as shown in FIG. 28 is set so as to resolve horizontal fine lines.
Then, the wafer is exposed by the second pattern exposure in an exposure amount distribution pattern as shown in FIG.

The first mask M1 shown in FIG. 26 has a predetermined shape adjacent to at least the first direction X with the light-shielding portions (SX2, SX4, SX6) of the non-light-shielding portions (SX1, SX3, SX5, SX7) interposed therebetween. Region (SX1, SX3, S
X5 and SX7) give a phase difference substantially an odd multiple of π to the light propagating in each region, and the non-light-shielding portion (SX2a)
Are formed such that predetermined regions adjacent to each other across the boundary provide a phase difference substantially odd multiple of π to light propagating through each region. are doing.

The first mask M1 has a non-light-shielding portion (SX
5, SY3) such that predetermined regions (SX5, SY3) adjacent to each other along the second direction Y with the light-shielding portion (SY2) interposed therebetween provide a phase difference of substantially π between light propagating in each region. It is composed.

The second mask M2 in FIG. 28 is adjacent to at least the second direction Y different from the first direction X with the light-shielding portion (SY2) in the non-light-shielding portions (SY1, SY3) interposed therebetween. The predetermined areas (SY1, SY3) provide a phase difference substantially odd multiple of π between the light propagating in each area, and a fourth direction different from the third direction Ya in the non-light-shielding portion (SY2a). A boundary 50 having a phase along Xa is formed, and predetermined regions adjacent to each other across the boundary 50 are configured to provide a phase difference of substantially an odd multiple of π between light propagating in each region. .

The exposure dose distribution on the wafer thus double-exposed is as shown in FIG. Here, if the threshold value of the resist is set between 0 and 2 as in the previous embodiment, a desired resist pattern as shown in FIG. 30B can be obtained.

FIGS. 31 to 35 are explanatory views of a mask and an exposure method according to the sixth embodiment of the present invention. In this embodiment, the same pattern as shown in the previous embodiment as shown in FIG. 42 is exposed.

First, paying attention to a vertical fine pattern, a mask (first mask) in which a phase shift region PH is set as shown in FIG. 31 so as to resolve vertical fine lines is used. The wafer is exposed in the exposure amount distribution pattern as shown in FIG. 32 by the first pattern exposure. At this time, the area in which a fine pattern can be formed is increased by partially considering the vertical direction.

Next, paying attention to the horizontal fine pattern, a mask (second mask) in which the phase shift area PH is set as shown in FIG. 33 so as to resolve horizontal fine lines is used. The wafer is exposed in the exposure amount distribution pattern as shown in FIG. 34 by the second pattern exposure. The exposure is basically the same as in the fifth embodiment.

The exposure dose distribution on the wafer thus double-exposed is as shown in FIG. Here, if the threshold value of the resist is set between 0 and 2 as in the previous embodiment, a desired resist pattern as shown in FIG. 35B can be obtained.

In the present invention, a plurality of (three or more) pattern exposures are performed by using a set of three or more masks each having a phase shift region having a different phase shift effect on a desired pattern. Is also good.

FIG. 36 is a schematic view showing a main part of a high-resolution exposure apparatus for exposing a set of masks provided with phase shift regions having different phase shift effects to desired patterns according to the present invention.

In FIG. 36, 221 is KrF, ArF
Excimer laser or F ₂ excimer laser, 222
Is an illumination optical system, 223 is a mask (reticle), 224 is a mask stage, 227 is a projection optical system for reducing and projecting the circuit pattern of the mask 223 onto the wafer 228, 225 is a mask (reticle) changer, and the stage 224.
In order to supply one of the set of masks selectively.

In FIG. 36, reference numeral 229 denotes X used for projection exposure.
This stage 229 is an optical system 2
27, a plane orthogonal to the optical axis and movable in the optical axis direction, and its position in the XY directions is accurately controlled using a laser interferometer or the like.

The apparatus shown in FIG. 36 includes a reticle positioning optical system (not shown) and a wafer positioning optical system (off-axis positioning optical system, TTL positioning optical system, and TT).
R positioning optical system).

The illumination optical system 222 of the exposure apparatus shown in FIG. 36 is configured to be able to switch between partially coherent illumination and coherent illumination. In the case of coherent illumination, the above-mentioned (1a) or (1a) shown in the block 230 is used. (1b)
Is supplied to the set of masks described above, and in the case of partial coherent illumination, the illumination light (2a) shown in the block 230 is supplied to a desired reticle.

Switching from partial coherent illumination to coherent illumination is performed by replacing the aperture stop, which is usually placed immediately after the fly-eye lens of the optical system 222, with a coherent illumination stop having an aperture diameter sufficiently smaller than this aperture stop. Just do it.

Using the above-described exposure method and exposure apparatus, various devices such as semiconductor chips such as ICs and LSIs, display elements such as liquid crystal panels, detection elements such as magnetic heads, and image pickup elements such as CCDs can be manufactured. .

The present invention is not limited to the embodiments described above, and can be variously modified without departing from the gist of the present invention. In particular, the number of exposures and the number of exposure steps in each step of exposure of one set of masks can be selected as appropriate, and the exposure can be adjusted as appropriate, such as by shifting the overlap. By performing such an adjustment, variations in circuit patterns that can be formed increase.

Next, an embodiment of a method for manufacturing a semiconductor device using the above-described exposure apparatus will be described.

FIG. 37 shows a flow of manufacturing a device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD).

In step 1 (circuit design), a circuit of a semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design.

On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4
The (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing and bonding) and a packaging process (chip encapsulation). And the like.

In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 38 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface.

In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to easily manufacture a highly integrated semiconductor device which has conventionally been difficult to manufacture.

[0123]

As described above, according to the present invention, a complex pattern can be formed by performing multiple exposures using a set of masks each having a phase shift region having a different phase shift effect on a desired pattern. Also, a mask, an exposure method, and an exposure apparatus which can perform exposure having both the high resolution of a Levenson mask and good defocus characteristics and can easily obtain a circuit pattern having a fine portion of, for example, 0.15 μm or less Can be achieved.

As described above, according to the present invention, by using a set of masks in which desired patterns are provided with phase shift regions having different phase shift effects, 0.15
It is possible to obtain a complicated pattern having a fine line width of μm or less.

[Brief description of the drawings]

FIG. 1 is a flowchart of an exposure method according to the present invention.

FIG. 2 is an explanatory diagram of an exposure pattern according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a first mask pattern arrangement according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of an exposure amount distribution on a wafer surface by a first exposure according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a second mask pattern arrangement according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of an exposure amount distribution on a wafer surface by a second exposure according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing resist exposure sensitivity characteristics.

FIG. 9 is a view showing pattern formation by development.

FIG. 10 is an explanatory diagram of a first mask pattern arrangement according to the second embodiment of the present invention.

FIG. 11 is an explanatory diagram of an exposure amount distribution on a wafer surface by a first exposure according to a second embodiment of the present invention.

FIG. 12 is an explanatory diagram of a second mask pattern arrangement according to the second embodiment of the present invention.

FIG. 13 is an explanatory diagram of an exposure amount distribution on a wafer surface by a second exposure according to the second embodiment of the present invention.

FIG. 14 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the second embodiment of the present invention.

FIG. 15 is an explanatory diagram of an exposure pattern according to a third embodiment of the present invention.

FIG. 16 is an explanatory diagram of a first mask pattern arrangement according to the third embodiment of the present invention.

FIG. 17 is an explanatory diagram of an exposure amount distribution on a wafer surface by a first exposure according to a third embodiment of the present invention.

FIG. 18 is an explanatory diagram of a second mask pattern arrangement according to the third embodiment of the present invention.

FIG. 19 is an explanatory diagram of an exposure amount distribution on a wafer surface by a second exposure according to a third embodiment of the present invention.

FIG. 20 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the third embodiment of the present invention.

FIG. 21 is an explanatory diagram of a first mask pattern arrangement according to a fourth embodiment of the present invention.

FIG. 22 is an explanatory diagram of an exposure amount distribution on a wafer surface by a first exposure according to a fourth embodiment of the present invention.

FIG. 23 is an explanatory diagram of a second mask pattern arrangement according to the fourth embodiment of the present invention.

FIG. 24 is an explanatory diagram of the exposure amount distribution on the wafer surface by the second exposure according to the fourth embodiment of the present invention.

FIG. 25 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the fourth embodiment of the present invention.

FIG. 26 is an explanatory diagram of a first mask pattern arrangement according to the fifth embodiment of the present invention.

FIG. 27 is an explanatory diagram of an exposure amount distribution on a wafer surface by a first exposure according to a fifth embodiment of the present invention.

FIG. 28 is an explanatory diagram of a second mask pattern arrangement according to the fifth embodiment of the present invention.

FIG. 29 is an explanatory diagram of the exposure amount distribution on the wafer surface by the second exposure according to the fifth embodiment of the present invention.

FIG. 30 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the fifth embodiment of the present invention.

FIG. 31 is an explanatory diagram of a first mask pattern arrangement according to the sixth embodiment of the present invention.

FIG. 32 is an explanatory diagram of the exposure amount distribution on the wafer surface by the first exposure according to the sixth embodiment of the present invention.

FIG. 33 is an explanatory diagram of a second mask pattern arrangement according to the sixth embodiment of the present invention.

FIG. 34 is an explanatory diagram of the exposure amount distribution on the wafer surface by the second exposure according to the sixth embodiment of the present invention.

FIG. 35 is an explanatory diagram of an exposure amount distribution and a resist image by double exposure according to the sixth embodiment of the present invention.

FIG. 36 is a schematic view of a main part of the exposure apparatus of the present invention.

FIG. 37 is a flowchart of a device manufacturing method of the present invention.

FIG. 38 is a flowchart of a device manufacturing method according to the present invention.

FIG. 39 is a schematic view of a main part of a conventional exposure apparatus.

FIG. 40 is an explanatory view of a conventional phase shift mask.

FIG. 41 is an explanatory view of a conventional pattern.

FIG. 42 is an explanatory view of a conventional pattern.

[Explanation of symbols]

 221 Excimer laser 222 Illumination optical system 223 Mask (reticle) 224 Mask (reticle) stage 225 Mask 226 Mask (reticle) changer 227 Projection optical system 228 Wafer 229 XYZ stage

Claims (17)

[Claims] 1. An exposure method for exposing a resist with a pattern, comprising: a first exposure for exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion; and a light-shielding portion and a non-light-shielding portion. A second exposure for exposing the resist through a second mask, wherein the shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern. The first and second exposures are performed in this order or the reverse order or simultaneously, and when performed sequentially, the resist is not developed between the two exposures, and the first mask is A predetermined region adjacent to the non-light-shielding portion along at least the first direction with the light-shielding portion interposed therebetween is configured to give a phase difference substantially an odd multiple of π to light propagating through each region; The second mask sandwiches the light shielding part in the non-light shielding part At least, adjacent predetermined regions along a second direction different from the first direction are configured to provide a phase difference of substantially an odd multiple of π between light propagating in each region. Exposure method characterized by the above-mentioned. 2. The method according to claim 1, wherein the first mask includes a predetermined region adjacent to the non-light-shielding portion along the second direction with the light-shielding portion interposed therebetween. 2. The exposure method according to claim 1, wherein the exposure method is configured to provide a phase difference. 3. The second mask according to claim 1, wherein the predetermined region adjacent to the non-light-shielding portion along the first direction with the light-shielding portion interposed therebetween is substantially π between light propagating through each region. 3. The exposure method according to claim 2, wherein a phase difference is provided. 4. The exposure method according to claim 1, wherein said first direction and said second direction are orthogonal to each other. 5. An exposure method for exposing a resist in a pattern, comprising: exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion; And a second exposure for exposing the resist through a second mask having the second mask. The shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are the same as the shape of the pattern. The first and second exposures are performed in the same order or in the reverse order or simultaneously. When the first and second exposures are sequentially performed, the development of the resist is not performed between the two exposures, and the first and second exposures are performed. The mask has a phase boundary formed along the first direction within the non-light-shielding portion, and predetermined regions adjacent to each other across the boundary provide a phase difference substantially odd multiple of π to light propagating through each region. The second mask is provided in the non-light-shielding portion. A phase boundary is formed along a second direction different from the first direction, and predetermined regions adjacent to each other across the boundary have a phase difference of substantially an odd multiple of π between light propagating in each region. An exposure apparatus characterized in that the exposure apparatus is configured to provide: 6. The exposure method according to claim 5, wherein said first direction and said second direction are orthogonal to each other. 7. An exposure method for exposing a resist in a pattern, comprising: a first exposure for exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion; and a light-shielding portion and a non-light-shielding portion. A second exposure for exposing the resist through a second mask, wherein the shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern. The first and second exposures are performed in this order or the reverse order or simultaneously, and when performed sequentially, the resist is not developed between the two exposures, and the first mask is A predetermined region adjacent to the non-light-shielding portion along at least the first direction with the light-shielding portion interposed therebetween provides a phase difference of substantially an odd multiple of π to light propagating through each region, and the light-shielding portion inside the non-light-shielding portion has Phase boundaries are formed along the direction Are arranged so as to give a phase difference substantially an odd multiple of π to light propagating through each area, and the second mask sandwiches the light-shielding part in the non-light-shielding part. The predetermined regions adjacent at least along a second direction different from the first direction provide a phase difference of substantially π odd times between lights propagating in the respective regions, and the second region is provided in the non-light-shielding portion. A phase boundary is formed along a fourth direction different from the third direction, and predetermined regions adjacent to each other across the boundary substantially have π between light propagating through each region.
An exposure method characterized by providing an odd-numbered phase difference. 8. The first mask, wherein a predetermined region adjacent to the non-light-shielding portion along the second direction with the light-shielding portion interposed therebetween is substantially π between light propagating through each region. 8. The exposure method according to claim 7, wherein an odd-number multiple phase difference is provided. 9. The second mask according to claim 1, wherein a predetermined region adjacent to the non-light-shielding portion along the first direction with the light-shielding portion interposed between the light-shielding portion and the light propagating through each region is substantially π. 8. The exposure method according to claim 7, wherein an odd-number multiple phase difference is provided. 10. The exposure method according to claim 7, wherein said first direction and said second direction are orthogonal to each other. 11. The exposure method according to claim 7, wherein said third direction and said fourth direction are orthogonal to each other. 12. The exposure method according to claim 7, wherein said first direction and said third direction are orthogonal to each other. 13. The exposure method according to claim 7, wherein said second direction and said fourth direction are orthogonal to each other. 14. An exposure method for exposing a resist in a pattern, comprising: a first exposure for exposing the resist through a first mask having a light-shielding portion and a non-light-shielding portion; and a light-shielding portion and a non-light-shielding portion. A second exposure for exposing the resist through a second mask, wherein the shape of the non-light-shielding portion of the first mask and the shape of the non-light-shielding portion of the second mask are substantially the same as the shape of the pattern. The first and second exposures are performed in this order or the reverse order or simultaneously, and when performed sequentially, the resist is not developed between the two exposures, and the first mask is A phase difference of an odd multiple of π is provided between light propagating through different regions of the non-light-shielding portion so that a part of the pattern is exposed to the resist. The non-shading so that a portion of the resist is exposed to the resist Exposure method characterized by between light propagating in the different regions of giving a phase difference of an odd multiple of [pi. 15. The exposure method according to claim 14, wherein a part of the pattern of the first mask and another part of the pattern of the second mask include a common part when projected onto a resist. . 16. An exposure apparatus having a double exposure mode for executing the exposure method according to claim 1. Description: 17. A device manufacturing method, comprising a step of transferring a device pattern to a wafer using the exposure method according to claim 1. Description: