JP3230014B2 - Projection exposure method and method of manufacturing semiconductor device using the exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure method required for a lithography technique for forming a fine pattern in a semiconductor integrated circuit device and the like, and a method of manufacturing a semiconductor device using the exposure method.

[0002]

2. Description of the Related Art With the recent increase in speed and integration of electronic devices such as semiconductor integrated circuit devices, it is required to form fine patterns. In response to this demand,
A lithography technique using a phase shift mask has attracted attention. Unexposed portions (patterns) accompanied by a sharp decrease in light intensity caused by a step portion of a phase shifter (a step for changing the phase of exposure light by 180 °) are attracting attention. The pattern forming method used is reported as an effective technique.

However, when a pattern is formed by this technique, an unexposed portion (pattern) is formed in all steps of the phase shifter, and therefore, in many applications, the pattern is generated at unnecessary steps of the phase shifter. It is necessary to perform a step of suppressing the formation of a pattern by the unexposed portion.

Therefore, conventionally, an unnecessary unexposed portion is overlapped and exposed (double exposure) using another exposure mask, or a step portion of a phase shifter which does not need to form a pattern is used. A technique has been proposed in which a steep drop in light intensity is mitigated by providing a multi-stage shifter (e.g., a 90-degree step) in a stepwise manner.

[0005]

However, of the methods proposed to remove unnecessary unexposed portions, which have been conventionally proposed, the double exposure method requires that a plurality of masks be manufactured and multiple exposures be performed. Because of this, the process of manufacturing the mask increases,
On the other hand, since it is necessary to ensure the alignment of the double exposure, there is a problem that the throughput (processing capacity) is reduced.

When a multi-stage shifter is used, a complicated and difficult process technology for forming a multi-stage shifter having an optically accurate shape is required, and a method of inspecting and correcting a manufactured phase shift mask is required. It is a big problem.

Therefore, the present invention provides a method for forming a pattern using an unexposed portion accompanied by a steep decrease in light intensity generated at a step portion of a phase shifter. It is an object of the present invention to provide a method for easily removing unnecessary unexposed portions without depending on a technique using the method.

[0008] In the projection exposure method according to the present invention, the cross-section
Exposure light with a light intensity distribution extending in the main direction
The phase shift mask for light is irradiated to the phase shift mask for light.
The light transmitted through the disk is projected onto the surface to be exposed, and the exposure phase
The main light intensity distribution of the exposure light of the shift mask pattern
And the main direction of the light intensity distribution of the exposure light.
Using different exposure characteristics for directions that are not parallel to the barrel direction
It is characterized by exposing .

Further, the exposure phase shift mask is irradiated with exposure light having a light intensity distribution extending in the main direction in the cross section, and the light transmitted through the exposure phase shift mask is projected onto a surface to be exposed, thereby forming an exposure light. Phase shifter edge of phase shift mask
The unexposed part with the sharp decrease in light intensity generated near the part
There is a direction in which the unexposed portion is not formed and a direction in which the unexposed portion is formed.
Exposure using the existing asymmetric exposure characteristics
I do.

In these cases, when an angle between the optical axis and the optical axis is represented by θ, the angle θ = sin ⁻¹ (0.4 to 1.0) from the optical axis.
It is possible to use exposure light having a light intensity distribution extending in the main direction within a section included in a range of × (NA) × 1 / m (where NA: numerical aperture of the projection lens, 1 / m: reduced projection magnification). it can.

In this case, a width of 0.2 × (λ / NA) × m ( λ: exposure light wavelength,
(NA: numerical aperture of the projection lens) Even if there is a linear light-shielding portion equal to or less than the numerical value, the effects of the present invention can be obtained.

Further, in the method of manufacturing a semiconductor device according to the present invention, the exposure phase shift mask is irradiated with exposure light having a light intensity distribution extending in the main direction in the cross section, and the light transmitted through the exposure phase shift mask is irradiated. Projected onto the surface to be exposed,
Using an asymmetric exposure characteristic in which there is a direction in which an unexposed portion is formed with a sharp drop in light intensity occurring near the end of the phase shifter of the exposure phase shift mask, and a direction in which the unexposed portion is not formed And a step of forming an opening such as a contact hole by a negative process and forming an isolated line portion to be a gate electrode or a wiring layer by a positive process.

[0013]

FIG. 1 is a diagram illustrating the configuration of a projection exposure apparatus used in the projection exposure method of the present invention. In this figure, 1 is a disk light source, 2 is an optical axis, 3 is an aperture, 4 is an aperture, 5 is a phase shift mask, 6 is a phase shifter, 7 is a projection lens system, and 8 is a surface to be exposed. In this projection exposure apparatus, a stop 3 having a plurality of apertures 4 distant from an optical axis 2 below a disk-shaped light source 1
Is used to form exposure light having a light intensity distribution having a main direction.

Then, the exposure light transmitted through the opening 4 of the stop 3 is irradiated onto a phase shift mask (exposure mask) 5,
The exposure light transmitted through the phase shift mask 5 is transmitted to the projection lens system 7.
Converges on the surface 8 to be exposed. The projection exposure method of the present invention is characterized by the shape of the light intensity distribution on the cross section of the exposure light.

FIGS. 2A and 2B are explanatory views of the configuration of the stop of the projection exposure apparatus used in the projection exposure method of the present invention. The reference numerals in this figure are the same as those used in FIG. The stop 3 shown in FIG. 2A is an example in which an opening 4 formed by a chord and an arc of one circle is provided on both sides of the optical axis, and the stop 3 shown in FIG. Is an example in which circular openings 4 are provided symmetrically on both sides of the optical axis.

The shape of the light intensity distribution of the cross section of the light transmitted through the stop 3 having these openings 4 is in the X direction (main direction).
It has a pattern that passes through a narrow optical axis in the Y direction (the direction orthogonal to the main direction). FIGS. 2A and 2B show examples of the aperture of the projection exposure apparatus of the present invention. The light intensity distribution of the cross section of the exposure light passing through the opening is changed in the X direction (main direction) and the Y direction. Since the object of the present invention can be achieved if different, appropriate means such as replacing the opening with a slit-shaped opening or providing a plurality of openings can be used. It can also be provided individually.

As described above, when the phase shift mask having the 180 ° phase shifter is irradiated with the exposure light having the light intensity distribution of the cross section different in the X direction (main direction) and the Y direction, the phase shifter is moved in the X direction and the Y direction. The light passes through the vicinity of the step and is converged by the projection lens system, causing asymmetry in the exposure characteristic of the pattern projected on the surface to be exposed.

FIG. 3 is a light intensity distribution diagram after the exposure light has passed through a phase shifter step parallel to the main direction. The horizontal axis of this figure indicates the distance from the step of the phase shifter of the phase shift mask, and the vertical axis indicates the light intensity of the exposure light after passing through the phase shift mask.

In this figure, the wavelength of the exposure light is 365 nm,
The calculation results obtained by the simulation when the numerical aperture (NA) is 0.54 are shown. The solid line indicates the case where the focus is just-focused, and the broken line indicates the case where the focus is 0.75 μm. In this case, the incident angle of light from the disc-shaped light source that enters the phase shift mask through the aperture of the stop is represented by θ =
sin ⁻¹ (0.6 to 1.0 × (NA) / m). Here, NA is the numerical aperture of the projection lens, and 1 / m is the reduced projection magnification.

According to this figure, both in the case of just-focusing and in the case of defocusing of 0.75 μm, the exposure light transmitted through the vicinity of the step portion of the phase shifter of the phase shift mask has a portion where the light intensity is sharply reduced. It can be seen that a steep linear unexposed portion having a fine width is formed over the entire thickness of the used photoresist film having a thickness of about 1 μm.

Therefore, if a positive photoresist film is used, a fine line-shaped resist pattern can be formed. By using this line-shaped resist pattern as a mask and removing the underlying film by etching, fine lines can be formed. Can be formed.

Conversely, if a negative photoresist film is used, a resist pattern having a linear space can be formed. By using the resist pattern having the linear space as a mask, the underlying film is removed by etching. A film having a linear space can be formed.

FIG. 4 is a light intensity distribution diagram after the exposure light has passed through the phase shifter step perpendicular to the main direction.
The horizontal axis and the vertical axis in this figure are the same as in FIG. 3, and the exposure conditions are also the same as those in FIG.

According to this figure, when just-focused, the phase shift mask is located near the step of the phase shifter in FIG.
When there is no sharp decrease in light intensity as described above and the light intensity is defocused by 0.75 μm, the light intensity rises to almost 1.0, but a light intensity distribution that is almost flat overall is obtained,
In particular, it is understood that a linear unexposed portion is not formed.

Therefore, if a positive photoresist film is used, the resist pattern does not remain after development. Therefore, when etching is performed as described with reference to FIG. 3, the film thereunder is removed by etching. Conversely, when a negative photoresist film is used, a resist pattern having no opening is formed, and the underlying film can be prevented from being etched.

From FIGS. 3 and 4, according to the present invention, both the just focus characteristic and the defocus characteristic representing the light intensity distribution in the thickness direction of the resist film are close to the ideal state where the effect of the present invention is strongly exhibited. It can be seen that the interference of the exposure light after passing through the phase shifter step perpendicular to the main direction of the exposure light is prevented.

As described above, only by changing the cross-sectional shape of the exposure light, a single exposure using a single phase shift mask having no special structure such as a multi-step end allows the phase shifter step to be performed. Unnecessary unexposed portions generated in the above can be removed.

[0028]

Embodiments of the present invention will be described below.

(First Embodiment) FIGS. 5A and 5B are explanatory views of the projection exposure method of the first embodiment. FIG. 5A shows an exposure phase shift mask (reticle) used in the projection exposure method of the first embodiment, and FIG. 5B shows a pattern formed by the projection exposure method of the first embodiment. . In this figure, 11 is a light shielding film, 12 is a 180 ° phase shifter,
13 is a step in the X direction, 14 is a step in the Y direction, 15 is exposure light, 16 is a linear pattern, and 17 is a pad.

As described with reference to FIGS. 1 and 2, the provision of the stop 3 having the opening 4 in the disc-shaped light source 1 allows exposure light having a light intensity distribution extending in the main direction (X direction) in the cross section. The phase shift mask 5 is irradiated, and the light transmitted through the phase shift mask 5 is converged by a projection lens system 7 and projected on a surface 8 to be exposed to expose a photoresist film applied to the surface.

A phase shift mask (FIG. 5A) used in the projection exposure method of the first embodiment is formed on a transparent substrate.
A rectangular phase formed by a step 13 in the X direction parallel to the main direction (X direction) of the light-shielding film 11 corresponding to the pad and the exposure light 15 and a step 14 in the Y direction orthogonal to the direction. A shifter 12 is formed.

The pattern (FIG. 5B) formed by the projection exposure method of the first embodiment using the exposure light 15 and the phase shift mask shown in FIG. Linear pattern 1 of fine width by step 13
6 is formed, and the light transmitted through the step portion 14 in the Y direction of the phase shifter 12 is orthogonal to the main direction of the exposure light 15,
Since the phases of the exposure light passing through this point do not match, and no phase shift of 180 ° occurs, no unexposed portion is formed and no linear pattern occurs.

In this embodiment, an isolated line portion serving as a fine gate electrode of an integrated circuit device using a MOSFET is formed by forming a linear pattern 16 with a conductive film and employing a positive process. The present invention can be applied to a case where an opening such as a contact hole is formed by adopting a negative process.

FIGS. 6A and 6B are micrographs of a pattern for explaining the effect of the first embodiment. This figure 6
(A) is a SEM photograph of the tip (left end in FIG. 5 (A)) of the pattern formed using the conventional disk-shaped light source, and FIG. 6 (B) is the tip of the pattern formed by this embodiment. 5 is an SEM photograph of a part. The thickness of the etching resist used for forming the patterns of these photographs was about 1 μm, and the width of the pattern resist was about 0.15 μm, but all the steps of the phase shifter (X direction, Y direction) It can be seen that a fine linear pattern is formed in (direction).

FIG. 6B shows a case where exposure is performed by exposure light having a main direction in the X direction as in this embodiment, and a pattern is formed by a steep unexposed portion in the X direction. However, it can be seen that no pattern is formed in the Y direction. These photographs show an example of a positive process (a process for forming a resist line pattern). However, if a negative process is performed, it is not necessary to explain that a space pattern is formed.

In this embodiment, with respect to the main direction (X direction) of the exposure light 15, a step 13 in the X direction and
Although the rectangular phase shifter formed by the Y-direction steps 14 perpendicular to the phase shifters has been described, the steps of the phase shifters need not necessarily be perpendicular to each other, for example, the steps of the phase shifters crossing at an angle of 45 °. The effect of erasing the unexposed portions was sufficiently obtained also in the above.

(Second Embodiment) FIGS. 7A and 7B are explanatory views of a projection exposure method according to a second embodiment. FIG. 7A is an explanatory diagram of a phase shift mask used in the projection exposure method of the second embodiment, and FIG. 7B is an explanatory diagram of a pattern formed by the projection exposure method of the second embodiment. In this figure, 21 is a light shielding film, 22 is a 180 ° phase shifter, 23 is a step in the X direction, 24 and 25 are steps inclined at 45 ° with respect to the X direction, 26 is a step in the Y axis direction, and 27 is exposure Reference numeral 28 denotes a linear pattern, and reference numeral 29 denotes a pad.

Also in this embodiment, the photoresist film is exposed using the phase shift mask by the exposure apparatus described with reference to FIGS.

FIG. 7A shows a part of a phase shift mask (reticle) used in the projection exposure method of the second embodiment, and a light shielding film 2 corresponding to a pad is formed on a transparent substrate.
1 and a step 23 in the X direction which is the main direction of the exposure light 27
And a pentagonal phase shifter 22 formed by a step 26 in the Y direction and two steps 24 and 25 inclined 45 ° from the upper end of the step 26 in the Y direction.

FIG. 7B shows a pattern formed by the projection exposure method of the second embodiment using the exposure light 27 and the phase shift mask shown in FIG. A fine linear pattern 28 is formed by an X-direction step 23 of the phase shifter 22, and light and Y-direction steps corresponding to the X-direction step 23 of the phase shifter 22 and two steps 24 and 25 inclined by 45 °. The light of the portion 26 is emitted in the main direction (X
Direction) at 45 ° and 90 °,
There is no linear pattern without a phase shift of 0 °.

According to this embodiment, as in the first embodiment, the present invention can be applied to a case where a gate electrode of a MOSFET is formed by a positive process. Further, an opening for making contact with a source region and a drain region can be formed by a negative process using a phase shifter used for forming a gate electrode.

Here, the angle between the incident direction of the exposure light used in each of the above embodiments and the optical axis and the optical axis will be examined. As a matter of course, in principle, if the angle θ between the incident direction of the exposure light to the exposure mask and the optical axis is small, the effect of erasing unnecessary unexposed portions of unnecessary steps generated in the steps of the phase shifter is reduced, If θ is large, the effect of erasing unnecessary exposure patterns in the step portion is large. However, when θ is increased, the resolution of the exposure pattern deteriorates.

According to the experiments by the inventors, when the angle formed with the optical axis is θ, θ = sin ⁻¹ (0.4 to 1.0 × (N
A) × 1 / m (where NA: numerical aperture of projection lens, 1
/ M: reduced projection magnification) when using exposure light having a light intensity distribution having a main direction in a direction included in a range included in a range including:
It has been confirmed that the effect of eliminating unnecessary unexposed portions generated at the step portion of the phase shifter can be maintained even when the photoresist film thickness is large and the exposure amount is small, while maintaining the resolution in a good range. Was.

Assuming that the numerical aperture NA of the projection lens is 0.54 and the reduced projection magnification m is 5, sin ^-1
0.43 to sin ^-1 0.11, that is, approximately 2 ° to 6
°.

Third Embodiment In each of the above embodiments, the case where a fine linear pattern, for example, a gate electrode is formed by the step portion of the phase shifter has been described. However, when manufacturing a phase shift mask (reticle) by forming a phase shifter after forming a light shielding pattern corresponding to a pad or the like with a light shielding film such as a chrome thin film on a transparent substrate,
There is a possibility that misalignment may occur between the previously formed light-shielding pattern and the later formed phase shifter.

Therefore, a fine linear light-shielding pattern is formed at the same time as other light-shielding patterns, and a phase shifter is formed so that a step portion comes on the fine linear light-shielding pattern. An unexposed pattern is formed at a precise but not steep position, a steep unexposed portion is formed by a step portion of the phase shifter, and a steep unexposed portion is formed at a precise position by both unexposed portions. It is possible.

FIG. 8 is an explanatory view of the projection exposure method of the third embodiment. This figure shows a part of an exposure mask (reticle), 31 is a light shielding pattern corresponding to a pad, 32 is a fine linear light shielding pattern, 33 is a phase shifter, and 34 is X
The step portion 35 in the direction is a step portion in the Y direction.

In this embodiment, on a transparent substrate,
A light-shielding pattern 31 corresponding to a pad and a fine linear light-shielding pattern 32 are formed by a vapor-deposited film such as chrome, and a step 34 in the X direction is provided thereon with a fine linear light-shielding pattern 3.
2, a phase shifter 33 is formed.

According to this embodiment, the step portion 34 in the X direction of the phase shifter has a size on the mask of 0.2 × (λ / N
A) × m ( λ: wavelength of exposure light, NA: aperture of projection lens
Even if the linear light-shielding pattern 32 of ( number ) exists, generation of a steep unexposed portion due to the step portion 34 in the X direction of the phase shifter 33 is not particularly hindered. A displacement is allowed in the above range.

(Fourth Embodiment) In the projection exposure method according to the present invention, a further mode is achieved by changing the main direction of the exposure light by appropriately rotating the aperture stop provided below the disk-shaped light source. Conceivable.

FIGS. 9A to 9C are explanatory views of the projection exposure method of the fourth embodiment. FIG. 9A shows a phase shift mask having a rectangular phase shifter, and FIG. 9B shows a linear exposure pattern when the main direction of the exposure light is in the X direction (horizontal direction in the figure). 9 (C) shows a linear exposure pattern when the main direction of the exposure light is orthogonal to the X direction. In this figure, 41 is a phase shifter, 42 is an exposure pattern in the X direction, and 43 is an exposure pattern in the Y direction.

In this embodiment, first, a phase shift mask having a plurality of rectangular phase shifters 41 is irradiated with exposure light whose main direction is in the X direction, so that the surface to be exposed is stepped in the X direction of the phase shifter. A large number of linear patterns in the X direction are formed by steep unexposed portions. Thereafter, the main direction of the exposure light is rotated by 90 °, and the other surface to be exposed is exposed using this phase shift mask, so that a plurality of linear portions in the Y direction are formed by the step portion in the Y direction of the phase shifter. An unexposed pattern is formed.

According to this embodiment, by using a single phase shift mask having a phase shifter, it is possible to form a pattern of an unexposed portion corresponding to the shape of a step in each direction orthogonal to the phase shifter. .

In this embodiment, a rectangular phase shifter having orthogonal steps has been described. However, the phase shifter may be a polygon having an arbitrary angle or a phase shifter surrounded by a curve having a gentle curvature. By forming and rotating the exposure light by an angle corresponding to the shape of the step of the phase shifter, the same effect as that of the embodiment can be obtained.

Although the description of each of the above embodiments has been limited to the case where a phase shift mask is used, the principle of the present invention can be applied to an exposure mask formed of a light shielding film having no phase shifter. Can be.

(Fifth Embodiment) FIG. 10 is an explanatory diagram of a projection exposure method according to a fifth embodiment. FIG. 10 is an explanatory view of an exposure mask used in the projection exposure method of the fifth embodiment. In this figure, 51 is a line and space light shielding pattern in the X direction, 52 is a line and space light shielding pattern in the Y direction, and 53 is exposure light. Also in this embodiment, the photoresist film is exposed using the exposure mask described above with reference to FIGS.

FIG. 10 shows a part of an exposure mask (reticle) used in the projection exposure method of the fifth embodiment.
When the main direction of the exposure light 53 is the X direction on the transparent substrate, a line and space light shielding pattern 51 in the X direction and a line and space light shielding pattern 52 in the Y direction orthogonal to the X direction are formed. I have.

According to the projection exposure method of this embodiment, the line and space light-shielding pattern 5 in the X direction is formed on the surface to be exposed.
1, a line-and-space exposure pattern having a high resolution is formed. However, the pattern formed by the line-and-space light-shielding pattern 52 in the Y direction orthogonal to the X direction is inferior in resolution. Occurs. Therefore, by adjusting the amount of exposure and the progress of development, only a line-and-space photoresist pattern in the X direction can be formed.

Contrary to this description, assuming that the main direction of the exposure light is the Y direction, only the line and space photoresist pattern in the Y direction can be formed.

That is, by rotating the stop 3 having an opening 4 provided below the light source 1 shown in FIGS. 1 and 2 by 90 °, two types of exposure patterns can be obtained using one exposure mask. Can be selectively formed.

[0061]

As described above, according to the present invention,
It is possible to remove an exposure pattern generated by an end in an unnecessary direction of a phase shifter without using a plurality of masks or a multi-stage shifter, thereby manufacturing a highly integrated semiconductor device having a fine pattern. Becomes easier.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a projection exposure apparatus used for a projection exposure method of the present invention.

FIGS. 2A and 2B are diagrams illustrating the configuration of a diaphragm of a projection exposure apparatus used in the projection exposure method of the present invention.

FIG. 3 is a light intensity distribution diagram after the exposure light has passed through a phase shifter step parallel to the main direction.

FIG. 4 is a light intensity distribution diagram after the exposure light has passed through a phase shifter step perpendicular to the main direction.

FIGS. 5A and 5B are explanatory views of the projection exposure method of the first embodiment.

FIGS. 6A and 6B are micrographs of patterns showing the effect of the first embodiment.

FIGS. 7A and 7B are explanatory views of a projection exposure method according to a second embodiment.

FIG. 8 is an explanatory diagram of a projection exposure method according to a third embodiment.

FIGS. 9A to 9C are explanatory views of a projection exposure method according to a fourth embodiment.

FIG. 10 is an explanatory diagram of a projection exposure method according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc-shaped light source 2 Optical axis 3 Stop 4 Aperture 5 Phase shift mask 6 Phase shifter 7 Projection lens system 8 Exposure surface 11 Light-shielding film 12 180 ° phase shifter 13 Step in X direction 14 Step in Y direction 15 Exposure light Reference Signs List 16 linear pattern 17 pad 21 light shielding film 22 180 ° phase shifter 23 step in X direction 24, 25 step inclined at 45 ° from X direction 26 step in Y direction 27 exposure light 28 linear pattern 29 pad 31 Light-shielding pattern corresponding to pad 32 Fine linear light-shielding pattern 33 Phase shifter 34 Step in X direction 35 Step in Y direction 41 Phase shifter 42 Exposure pattern in X direction 43 Exposure pattern in Y direction

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027 G03B 27/32 G03F 7/20 521

Claims (7)

(57) [Claims] An exposure light having a light intensity distribution extending in a main direction in a cross section is applied to an exposure phase shift mask, and light transmitted through the exposure phase shift mask is projected onto a surface to be exposed. Phase shift mask pattern , exposure light
A direction substantially parallel to the main direction of the light intensity distribution and the exposure light
In the direction not parallel to the main direction of the light intensity distribution of
A projection exposure method wherein exposure is performed using exposure characteristics . 2. An exposure phase shift mask is irradiated with exposure light having a light intensity distribution extending in a main direction in a cross section, and light transmitted through the exposure phase shift mask is projected onto a surface to be exposed. Near the end of the phase shifter of the phase shift mask
Unexposed areas are formed with a sharp decrease in light intensity that occurs.
Direction and the direction where the unexposed portion is not formed exist.
A projection exposure method wherein exposure is performed using symmetric exposure characteristics . 3. An exposure phase shift mask is irradiated with exposure light having a light intensity distribution extending in a main direction in a cross section, and the light transmitted through the exposure phase shift mask is projected onto a surface to be exposed. Near the end of the phase shifter of the phase shift mask
Unexposed areas are formed with a sharp decrease in light intensity that occurs.
Direction and the direction where the unexposed portion is not formed exist.
Using a symmetrical exposure characteristic, a step in one direction of the phase shifter
Therefore, a first pattern is formed, and then the main pattern of the exposure light is formed.
Exposure by changing the direction of the phase shifter.
The second step in the other direction is formed by the step in the direction.
Projection exposure method according to claim Rukoto. 4. When an angle between the optical axis and the optical axis is θ,
θ = sin ⁻¹ (0.4 to 1.0) × (NA) × 1 / m
(However, NA: numerical aperture of projection lens, 1 / m: reduction
Extends in the main direction within the section included in the range of (projection magnification)
Characterized by using exposure light having a light intensity distribution
The projection exposure method according to claim 1 . 5. A phase shifter having a width of 0.2 × (λ /
NA) × m (λ: wavelength of exposure light, NA : aperture of projection lens)
Number) The following linear light shielding portion is present.
The projection exposure method according to any one of claims 1 to 4 . 6. A light intensity distribution extending in a main direction in a cross section.
Irradiating the exposure phase shift mask with
The light transmitted through the optical phase shift mask is projected onto the surface to be exposed.
Near the end of the phase shifter of the phase shift mask for exposure.
Unexposed areas are formed with a sharp decrease in light intensity that occurs.
Direction and the direction where the unexposed portion is not formed exist.
Contact using negative process with symmetrical exposure characteristics
The opening, such as a through hole, is formed in the gate electrode by a positive process.
Alternatively, forming an isolated line portion serving as a wiring layer is
A method for manufacturing a semiconductor device. 7. The width of the step of the phase shifter is 0.2 × (λ /
NA) × m (λ: wavelength of exposure light, NA: aperture of projection lens)
Number) The following linear light shielding portion is present.
Item 7. A method for manufacturing a semiconductor device according to Item 6.