TWI656410B - Exposure device, exposure method, and article manufacturing method - Google Patents

Abstract

Provided is an exposure apparatus for exposing a substrate using a phase shift mask. The phase shift mask includes a first region and a second region that make phases of transmitted light different from each other at a reference wavelength. The exposure apparatus is characterized by including a first changing section for changing An illumination wavelength of light illuminating the phase shift mask; a projection optical system that projects a pattern image of the phase shift mask onto the substrate; a second changing unit that changes a spherical aberration of the projection optical system; control And controlling the change of the spherical aberration by the second changing unit based on the illumination wavelength and the reference wavelength changed to a wavelength different from the reference wavelength by the first changing unit, and changing the To illuminate the phase shift mask at the illumination wavelength of a wavelength different from the reference wavelength, using the projection optical system having the spherical aberration changed according to the illumination wavelength and the reference wavelength, A pattern image of the phase shift mask is projected onto the substrate.

Description

Exposure device, exposure method, and article manufacturing method

The present invention relates to an exposure device, an exposure method, and a method for manufacturing an article.

In an exposure apparatus used to transfer a pattern of a mask to a substrate in a manufacturing process (lithography process) of a semiconductor device or the like, it is required to improve the resolution performance along with miniaturization and high integration of circuit patterns. As one method for improving the resolution performance, a phase shift method using a phase shift mask in which a first region and a second region in which the phase of transmitted light differs by 180 degrees are provided is known.

In the phase shift method, if the phase difference between the transmitted light in the first region and the transmitted light in the second region deviates by 180 degrees due to a manufacturing error of the phase shift mask or the like, the focal depth may change. Japanese Patent Application Laid-Open No. 10-232483 proposes a method of correcting the phase difference due to a result of measuring a phase difference between transmitted light in a first region and transmitted light in a second region in a phase shift mask. Changes in depth of focus due to deviations of 180 degrees.

In order to further improve the resolution performance of the exposure device, the wavelength of the illumination light (that is, the exposure wavelength) that illuminates the phase shift mask may be shortened. However, if the wavelength of the illumination light is deviated from the transmitted light in the first region and the When the phase difference of the transmitted light becomes a reference wavelength of 180 degrees, the focal depth may change depending on the deviation of the wavelength of the illumination light and the reference wavelength. In the method described in Japanese Patent Application Laid-Open No. 10-232483, the focal depth is corrected based on the measurement result of the phase difference between the transmitted light in the first region and the transmitted light in the second region. Therefore, it is necessary to measure after changing the wavelength of the illumination light. With this phase difference, a procedure for correcting the depth of focus may be complicated.

The present invention provides a technique that is advantageous in terms of resolution performance and depth of focus when a substrate is exposed using a phase shift mask.

As an exposure apparatus of one aspect of the present invention, a substrate is exposed by using a phase shift mask. The phase shift mask includes a first region and a second region that make phases of transmitted light different from each other at a reference wavelength. 1 changing unit for changing an illumination wavelength of light illuminating the phase shift mask; projection optical system for projecting a pattern image of the phase shift mask onto the substrate; second changing unit for changing the projection optics A spherical aberration of the system; and a control unit that controls the processing performed by the second changing unit based on the illumination wavelength and the reference wavelength changed to a wavelength different from the reference wavelength by the first changing unit. When the spherical aberration is changed, the phase shift mask is illuminated at the illumination wavelength changed to a wavelength different from the reference wavelength. The projection optical system of the spherical aberration projects a pattern image of the phase shift mask onto the substrate.

Other features of the present invention are illustrated by the following illustrative examples with reference to the drawings. The description of the embodiment will become clear.

1‧‧‧lighting optical system

2‧‧‧ projection optical system

3‧‧‧Control Department

4‧‧‧ console department

5‧‧‧Mask

6‧‧‧ Substrate

11‧‧‧ light source

12‧‧‧ Wavelength Filter

13‧‧‧ND Filter

14‧‧‧Optical Integrator

15‧‧‧Focus lens

16a‧‧‧ Beamsplitter

16b‧‧‧detector

17‧‧‧ light shield

18‧‧‧ lens

19‧‧‧Reflector

21‧‧‧optical element

22‧‧‧Keystone

23‧‧‧ concave mirror

24‧‧‧ Optics

25‧‧‧ convex mirror

26‧‧‧NA aperture

27‧‧‧Driver

31‧‧‧solid line

32‧‧‧ dotted line

33‧‧‧Single-dot

100‧‧‧ exposure device

M‧‧‧ Phase shift mask

P‧‧‧ substrate

FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus.

FIG. 2 is a diagram showing a result obtained by performing photolithography and simulation of focusing characteristics using a phase shift mask.

FIG. 3 is a diagram for explaining a definition of a focal depth.

FIG. 4 is a diagram showing results obtained by performing photolithography and simulation of focusing characteristics using a phase shift mask.

FIG. 5 is a diagram showing a relationship between a driving amount of an optical element and a spherical aberration occurring in a projection optical system.

FIG. 6 is a flowchart showing a method of obtaining change amount information.

FIG. 7 is a diagram showing focus characteristics regarding each of a plurality of conditions of spherical aberrations of the projection optical system.

FIG. 8 is a diagram showing focusing characteristics regarding each of a plurality of conditions of spherical aberrations of the projection optical system.

FIG. 9 is a diagram showing an example of change amount information.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, the same reference numerals are assigned to the same components or elements, and redundant descriptions are omitted.

<First Embodiment>

The exposure apparatus 100 according to the first embodiment of the present invention will be described. In order to improve the resolution (resolution) of the exposure apparatus 100 according to the first embodiment, a phase shift mask M including a first region and a second region that make transmitted light different from each other is used for a substrate such as a single crystal silicon substrate or a glass substrate. P for exposure. There are several types of phase shift masks M, including a Levinson type phase shift mask and a half-tone type phase shift mask. Half-tone phase shift masks are highly convenient and are most commonly used in the field of semiconductor manufacturing. The half-tone phase shift mask is designed to include a first region (transmission region) through which light is transmitted and a second region (local transmission region) where light transmittance is smaller than the first region. The phase difference between the transmitted light in the region and the transmitted light in the second region is 180 degrees. In the second region, instead of a light-shielding film called a binary mask, a local transmission film having a light transmittance of, for example, 3% to 20% is provided. As a material of the local transmission film, for example, chromium oxide-nitrogen is used Chromium oxide, molybdenum nitride silicide, etc. When the half-tone phase shift mask configured as described above is used, the edges of the pattern image projected onto the substrate P are emphasized, so that the resolution performance can be improved.

Next, the configuration of the exposure apparatus 100 according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus 100 according to the first embodiment. The exposure apparatus 100 can include, for example, an illumination optical system that illuminates the phase shift mask M, a projection optical system that projects a pattern image of the phase shift mask M onto the substrate P, a control unit 3, and a console unit 4. The control unit 3 includes, for example, a CPU and a memory, and controls each part of the exposure apparatus 100 (controls an exposure process for exposing the substrate P). The console 40 is a unit for an operator to operate the exposure apparatus 100. In addition, exposure The device 100 can include a mask stage 5 capable of moving while holding the phase shift mask M, and a substrate mounting stage 6 capable of moving while holding the substrate P.

The illumination optical system 1 can include, for example, a light source 11, a wavelength filter 12, an ND filter 13, an optical integrator 14, a focusing lens 15, a beam splitter 16a, a detector 16b, a light shielding sheet 17, a lens 18, and a reflecting mirror 19. As the light source 11, for example, an ultrahigh-pressure mercury lamp that emits flood light (center-of-gravity wavelength 400 nm) including a plurality of bright-line spectra such as g-line, h-line, and i-line can be used. The wavelength filter 12 is configured to transmit light of a wavelength in a predetermined range and cut off light of a wavelength outside the range, that is, to narrow a band of flood light emitted from the light source 11. In the illumination optical system 1, a plurality of wavelength filters 12 having different wavelength ranges of transmitted light can be provided. In addition, by arranging one of the plurality of wavelength filters 12 on the optical path, the wavelength of light that illuminates the phase shift mask M can be changed. That is, the wavelength filter 12 has a function as a first changing section that changes the illumination wavelength. Here, in the first embodiment, the wavelength filter 12 is used as the first changing unit. However, for example, the light source 11 configured to change the wavelength of emitted light may be used as the first changing unit. In addition, the wavelength of the light which illuminates the phase shift mask M is hereinafter referred to as "illumination wavelength".

The ND filter 13 is used to adjust the intensity of light transmitted through the wavelength filter 12. The optical integrator 14 is an optical system for making the intensity distribution of the light to be irradiated to the phase shift mask M uniform. The light transmitted through the optical integrator 14 is condensed by the focusing lens 15 and is incident on the beam splitter 16a. Part of the light that has entered the beam splitter 16a is reflected by the beam splitter 16a and is incident on the detector 16b. The detector 16b is configured to detect the intensity of the incident light And the wavelength. Thereby, the control part 3 can control the light source 11 and the wavelength filter 12 so that the intensity and wavelength of the light transmitted through the focus lens 15 may become a desired value based on the detection result by the detector 16b. On the other hand, the light transmitted through the beam splitter 16 a passes through the light shielding sheet 17, the lens 18, and the reflection mirror 19 and enters the phase shift mask M. An opening for defining a range for illuminating the phase shift mask M is formed in the light shielding sheet 17, and an image of the opening is formed on the phase shift mask M through a lens 18.

The projection optical system 2 can include, for example, a correction optical element 21, a trapezoidal mirror 22, a concave mirror 23, an optical element 24, a convex mirror 25, and an NA diaphragm 26. The light having passed through the phase shift mask M is incident on the correction optical element 21. The correction optical element 21 includes, for example, a parallel flat plate, and by tilting the parallel flat plate with respect to the optical axis, it is possible to correct comet aberration, astigmatic aberration, and distortion aberration. The light transmitted through the correction optical element 21 is reflected by the trapezoidal mirror 22 and the concave mirror 23 and enters the convex mirror 25. Then, the light reflected by the convex mirror 25 is reflected on the surface of the concave mirror 23 and the trapezoidal mirror 22 and is incident on the substrate P. In addition, between the concave mirror 23 and the convex mirror 25 (for example, between the optical element 24 and the convex mirror 25 to be described later), an NA diaphragm 26 for changing the numerical aperture (NA) of the projection optical system 2 is disposed. The NA diaphragm 26 has an opening through which light passes, and the diameter of the opening is changed by a driving mechanism (not shown) through the driving mechanism, which can change the numerical aperture (NA) of the projection optical system 2.

In the exposure apparatus 100 that exposes the substrate P using the phase shift mask M in this way, with the recent miniaturization and high integration of circuit patterns, it is required to further improve the resolution performance. As a further improvement in resolution As one of the methods, there is a method of changing (shortening) the illumination wavelength by, for example, narrowing a band of flood light. However, if the illumination wavelength is changed, the phase difference between the transmitted light in the first region and the transmitted light in the second region becomes a reference wavelength of 180 degrees. Therefore, according to the deviation of the illumination wavelength and the reference wavelength, the focusing characteristics are tilted and the focal length is changed. Deep may decrease. This phenomenon will be described with reference to FIG. 2.

FIG. 2 is a diagram showing results obtained by performing photolithography and simulation of focusing characteristics using a phase shift mask M having a hole pattern of 2.0 μm formed. The graph shown in FIG. 2 shows the focusing characteristics, the horizontal axis is the defocus amount, and the vertical axis is the CD value (resolution line width) as the resolution performance. In addition, the solid line 31 in FIG. 2 indicates that the reference wavelength of the phase-shift mask M is the h-line wavelength (405 nm), and the light is flooded with a plurality of bright-line spectra including the g-line, h-line, and i-line (center-of-gravity wavelength 400 nm). The result when this phase shift mask M is illuminated. A dotted line 32 in FIG. 2 shows a result when the reference wavelength of the phase shift mask M is set to an h-line wavelength, and the phase shift mask M is illuminated with an i-line (365 nm). A one-dot chain line 33 in FIG. 2 shows a result when the reference wavelength of the phase shift mask M is set to an i-line wavelength, and the phase shift mask M is illuminated with the i-line.

First, the definition of the depth of focus in this embodiment will be described with reference to FIG. 3. In this embodiment, the peak value (maximum value or minimum value) of the CD value in the focus characteristics is determined, a first value obtained by adding 10% of the target CD value to the peak value, and subtracting the target value from the peak value are determined. The second value is 10% of the CD value. Then, a range in which the CD value of the focusing characteristic is converged to a defocus amount between the first value and the second value is taken as the focal depth.

Next, referring to the solid line 31 and the dotted line 32 in FIG. The reference wavelength is a case where the phase shift mask M of the h-line wavelength (405 nm) is illuminated with light having an illumination wavelength of 400 nm, and a case where light is illuminated with an illumination wavelength of 365 nm (i-line). If the solid line 31 and the dotted line 32 are compared, it can be seen that the focal depth is 41 μm in the solid line 31 with the reference wavelength and the illumination wavelength being substantially the same. In contrast, in the dotted line 32 with the illumination wavelength being the i-line, the focusing characteristic becomes Steep characteristics, narrow focal depth to 32μm. This shows that if the illumination wavelength is changed in order to improve the resolution performance, the focal depth is reduced according to the deviation of the illumination wavelength and the reference wavelength.

On the other hand, if the phase shift mask M is illuminated with light (i-line) at an illumination wavelength of 365 nm as shown by the one-dot chain line 33 in FIG. 2, a phase shift whose reference wavelength is the i-line wavelength is used. The mask M can improve the focal depth to 36 μm. However, this indicates that a phase shift mask M having a changed illumination wavelength as a reference wavelength is required to be newly prepared. That is, in the conventional exposure apparatus, in order to improve the resolution performance by changing the illumination wavelength, for example, 30 nm or more, it is necessary to newly create a phase shift mask M based on the changed illumination wavelength.

Therefore, the exposure apparatus 100 according to the first embodiment corrects a change in the depth of focus caused by changing the illumination wavelength to a wavelength different from the reference wavelength, by changing the spherical aberration of the projection optical system 2. That is, the exposure device 100 includes a second changing unit that changes the spherical aberration of the projection optical system 2 and corrects a change in focal depth caused by changing the illumination wavelength to a wavelength different from the reference wavelength, based on the reference wavelength and the change. The second illumination section controls the second changing section. The second modification section can be included in the light path of the projection optical system 2 (for example, the concave mirror 23 The optical element 24 is disposed on the optical path between the convex mirror 25 and the driving unit 27 that drives the optical element 24. The optical element 24 includes, for example, a meniscus lens, and is driven by the driving portion 27 between the concave mirror 23 and the convex mirror 25 in a direction (X direction in FIG. 1) in which the ratio between the distance from the concave mirror 23 and the distance from the convex mirror 25 changes. By driving the optical element 24 in this way, the spherical aberration of the projection optical system 2 can be changed.

FIG. 4 is a diagram showing results obtained by performing photolithography and simulation of focusing characteristics using a phase shift mask M having a hole pattern of 2.0 μm formed. The graph shown in FIG. 4 shows the focusing characteristics, the horizontal axis is the defocus amount, and the vertical axis is the CD value (resolution line width) as the resolution performance. The solid line 41 in FIG. 4 indicates that the reference wavelength of the phase shift mask M is the h-line wavelength (405 nm). The result when the phase shift mask M is illuminated. The dotted line 42 in FIG. 4 shows the result when the reference wavelength of the phase shift mask M is set to the h-line wavelength, and the phase shift mask M is illuminated with an i-line (365 nm). The solid line 41 and the dotted line 42 in FIG. 4 correspond to the solid line 31 and the dotted line 32 in FIG. 2, respectively, and have focal depths of 41 μm and 32 μm, respectively.

In addition, a two-dot chain line 43 in FIG. 4 indicates a result when the spherical aberration of the projection optical system 2 is changed for the conditions of the dotted line 42. Specifically, the two-dot chain line 43 in FIG. 4 indicates that the optical element 24 is driven by the drive unit 27 so that the spherical aberration of the projection optical system 2 when the dotted line 42 is obtained is further added by + 0.1λ. The results. By changing the spherical aberration of the projection optical system 2 in this way, the focusing characteristics can be made close to the reference wave even under conditions where the reference wavelength and the illumination wavelength are different from each other. The solid line 41 is substantially the same as the illumination wavelength. That is, it is possible to correct the focal depth that has been changed by changing the illumination wavelength so that the focal depth when the reference wavelength and the illumination wavelength are substantially the same.

Here, the exposure device 100 (control unit 3) controls the second changing unit based on the information (the following change amount information) indicating the amount of change in the spherical aberration of the projection optical system 2 from the reference wavelength and the wavelength difference of the changed illumination wavelength. Just fine. For example, the control unit 3 obtains a relationship between a driving amount of the optical element 24 driven by the driving unit 27 and a spherical aberration occurring in the projection optical system 2 during the driving amount. This relationship may be a proportional relationship as shown in FIG. 5, for example. FIG. 5 is a diagram showing the relationship between the driving amount of the optical element 24 and the spherical aberration occurring in the projection optical system 2. In the horizontal axis of FIG. 5, the optical element 24 is moved from the reference position (driving amount = 0). The direction in which the concave mirror 23 is driven (the + X direction in FIG. 1) is set to the positive direction. Then, the control unit 3 determines the driving amount of the optical element 24 for correcting the change in the focal depth caused by changing the illumination wavelength based on the relationship and the change amount information, and controls the driving unit 27 in accordance with the obtained driving amount.

A method for obtaining the change amount information will be described below. The change amount information can be obtained, for example, by changing the illumination wavelength to each of a plurality of wavelengths different from each other, and obtaining a spherical aberration of the projection optical system having the maximum focal depth for each of the plurality of wavelengths. A specific procedure of a method of obtaining the change amount information will be described with reference to FIG. 6. FIG. 6 is a flowchart showing a method of obtaining change amount information. Each program of the flowchart shown in FIG. 6 can be executed by the control unit 3, but may be executed using a computer or the like external to the exposure apparatus 100. In addition, the following description uses a phase shift mask formed with a hole pattern of 2.0 μm. An example of obtaining the change amount information by the cover M is as defined in the following description in 1) and 2).

1) The spherical aberration of the projection optical system 2 when the optical element 24 is at the reference position is referred to as a reference spherical aberration (± 0 mλ).

2) The optimum focus position when the spherical aberration of the projection optical system 2 is a reference spherical aberration (± 0 mλ) is defined as “defocus amount = 0 μm”.

In S11, the control unit 3 acquires a focus characteristic (amount of defocus and resolution (CD value) for each of a plurality of conditions for changing the spherical aberration of the projection optical system 2 by moving the optical element 24 through the drive unit 27. )Relationship). For example, the control unit 3 can obtain the resolution (CD value) when the defocus amount is assigned to each of a plurality of conditions in which the spherical aberration of the projection optical system 2 is changed, as shown in FIGS. 7 and 8. Focus characteristics are obtained for each condition.

FIG. 7 and FIG. 8 are diagrams each showing a focus characteristic under each of the plurality of conditions. FIG. 7 is a result of adjusting the exposure amount so that the CD value when the defocus amount is 0 μm becomes the target value (2.0 μm), and obtaining the focusing characteristics regarding each condition. In addition, FIG. 8 adjusted the exposure amount so that the peak value of CD value in each condition might become a target value (2.0 micrometers), and obtained the result of the focus characteristic about each condition. Here, FIG. 7 and FIG. 8 are exemplified as the focus characteristics under each of a plurality of conditions, but in order to obtain the change amount information, it is only necessary to obtain the focus characteristics shown in either of FIG. 7 and FIG. 8. In addition, in FIGS. 7 and 8, the spherical aberration of the projection optical system 2 is changed at a pitch of 100 mλ within a range of ± 200 mλ with respect to the reference spherical aberration (± 0 mλ), but it is not limited to this, and may be any The range and pitch of changing the spherical aberration are intentionally changed.

Here, in this embodiment, a CD value is used as the resolution. However, in addition to the CD value, a contrast value, a NILS value (Normalized Image Log-Slope), or the like may be used. Resolution performance. In addition, as a method of obtaining the CD value, for example, a method may be adopted in which the substrate stage 6 includes a detection unit (for example, an image sensor) that detects a pattern image of the phase shift mask M, and a graph obtained through the detection unit is provided. Like getting a CD value. In addition, it is also possible to adopt a method in which the substrate P is actually exposed using a phase shift mask M, and the size of the pattern formed on the substrate P is measured with an external device, and a CD value is obtained based on the result obtained thereby .

In S12, the control unit 3 obtains a depth of focus for each of a plurality of conditions based on the focus characteristics obtained in S11, and selects a condition in which the depth of focus is the largest from the plurality of conditions (spherical image of the projection optical system 2). Bad change). Here, in the first embodiment, a condition in which the depth of focus is maximized is selected from a plurality of conditions, but is not limited thereto. For example, the control unit 3 may select a condition in which the illumination wavelength and the reference wavelength are the same and have the focal depth closest to the focal depth when the defocus amount is 0 μm from a plurality of conditions. In addition, the control unit 3 may select a condition in which the inclination at the peak position of the focus characteristic is the flattest from a plurality of conditions.

In S13, the control unit 3 determines whether to change the illumination wavelength and repeats the procedures of S11 to S12. For example, the control unit 3 determines a plurality of wavelengths at which the illumination wavelength should be changed, based on information about a range and a pitch in which the illumination wavelength is changed. Then, the control unit 3 performs the operation at all the determined wavelengths. In the case of the procedures of S11 to S12, it is determined that the procedure is not repeated, and when there are wavelengths in which the procedure of S11 to S12 is not performed, it is determined that the procedure is repeated. When it is determined that the procedures of S11 to S12 are repeated, the process proceeds to S14, and after the illumination wavelength is changed in S14, the process proceeds to S11. On the other hand, if it is determined that the routine of S11 to S12 is not repeated, the process proceeds to S15. When it progresses to S15, the control part 3 acquires the change amount of the spherical aberration which becomes the maximum focal depth with respect to each of the determined multiple wavelengths.

In S15, the control unit 3 determines the difference between each of the plurality of wavelengths determined in S14 and the reference wavelength of the phase shift mask M, and the relationship between the difference and the amount of change in spherical aberration with the maximum focal depth. Determined as change amount information. FIG. 9 is a diagram showing an example of change amount information obtained in S15. The change amount information is information indicating the change amount of the spherical aberration of the projection optical system 2 with respect to the wavelength difference between the reference wavelength and the changed illumination wavelength as described above. In the example shown in FIG. 9, the wavelength difference can be defined as a change from the change. The value obtained by subtracting the reference wavelength from the subsequent illumination wavelength. By determining the change amount information in this way, the control unit 3 can determine the spherical aberration of the projection optical system 2 based on the difference between the reference wavelength and the changed illumination wavelength and the change amount information shown in FIG. 9 when the illumination wavelength is changed. The amount of change. Then, the control unit 3 can obtain the optical element 24 based on the relationship between the amount of driving of the optical element 24 shown in FIG. 5 and the spherical aberration occurring in the projection optical system 2 and the amount of change in the obtained spherical aberration. Drive volume.

As described above, the exposure apparatus 100 according to the first embodiment is configured to correct the light generated by changing the illumination wavelength to a wavelength different from the reference wavelength. The method of changing the focal depth is to change the spherical aberration of the projection optical system 2 based on the reference wavelength and the changed illumination wavelength. Thereby, the exposure apparatus 100 does not need to newly create a phase shift mask, and can change the illumination wavelength so that the resolution performance of the exposure apparatus 100 may be improved.

Here, in this embodiment, the spherical aberration of the projection optical system 2 is changed by moving the optical element 24, but it is not limited to this. For example, a plurality of optical elements 24 having different amounts of change in the spherical aberration of the projection optical system 2 may be provided, and the spherical aberration of the projection optical system 2 may be changed by replacing the optical elements 24. In this case, the second changing unit that changes the spherical aberration of the projection optical system 2 can include a replacing unit for replacing the optical element 24. In addition, as a method of changing the spherical aberration of the projection optical system 2, there are a method of arranging a transparent flat plate on the light path in the projection optical system 2, a method of changing the distance between the phase shift mask M and the projection optical system 2, and the like. . Furthermore, in this embodiment, an example of the projection optical system 2 has been described using an OFFNER-type optical system. However, an optical system other than the OFFNER-type can be used as the projection optical system 2.

<Second Embodiment>

In the exposure device 100, if the illumination wavelength is changed to a wavelength different from the reference wavelength, as shown in FIG. 2, in addition to the depth of focus, the amount of defocus may change. In addition, after the second changing unit is controlled so as to correct a change in the depth of focus that occurs when the illumination wavelength is changed, the amount of defocus may not converge within the allowable range. Therefore, the exposure apparatus 100 includes a third changing unit that changes the defocus amount, and corrects the amount of defocus after the second changing unit is controlled. Method, it is sufficient to control the third change section. As the third modification unit, for example, at least one of the mask stage 5 and the substrate stage 6 can be used. When the mask stage 5 is used as the third changing unit, the phase shift mask M is moved in the direction (for example, the Z direction) in which the distance between the phase shift mask M and the projection optical system 2 is changed by using the mask stage 5. , Can change the amount of defocus. When the substrate stage 6 is used as the third changing unit, the defocus amount can be changed by moving the substrate P in the direction (for example, the Z direction) in which the distance between the substrate P and the projection optical system 2 is changed by the substrate stage 6. . Here, for example, when at least one of the mask stage 5 and the substrate stage 6 is used as the second changing unit, the optical element 24 and the driving unit 27 may be used as the third changing unit.

<Embodiment of Article Manufacturing Method>

The method of manufacturing an article according to an embodiment of the present invention is suitable for manufacturing, for example, an article having a micro device or a micro-structured element such as a semiconductor device. The method for manufacturing an article according to this embodiment includes a procedure for forming a latent image pattern using the above-mentioned exposure device on a photosensitizer coated on a substrate (a procedure for exposing a substrate), and a method for forming a latent image pattern in the procedure. Process for substrate development. Furthermore, the above-mentioned manufacturing method includes other well-known procedures (oxidation, film formation, vapor deposition, doping, planarization, etching, resist peeling, dicing, bonding, packaging, etc.). The manufacturing method of the article of this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of an article compared with the conventional method.

Although the present invention has been described in connection with exemplary embodiments, the present invention The invention should be understood not to be limited to the disclosed exemplary embodiments. The widest explanation should be provided to include all modifications and equivalents of structure and function in the scope of patent applications below. In the above-mentioned embodiment, an example of exposing with light having wavelengths including i-line, g-line, and h-line is shown, but the wavelength is not limited to this, and an example of exposing with light including wavelengths of g-line and h-line Use other wavelengths of light for exposure.

Claims (15)

An exposure device for exposing a substrate using a phase shift mask, the phase shift mask including a first region and a second region that make phases of transmitted light different from each other at a reference wavelength, and is characterized by including a first changing section, Changing the illumination wavelength of light illuminating the phase shift mask; a projection optical system that projects a pattern image of the phase shift mask onto the substrate; a second changing unit that changes a spherical image of the projection optical system And a control unit that controls the change of the spherical aberration by the second changing unit based on the reference wavelength and the changed illumination wavelength, thereby correcting the change to the A change in focal depth caused by wavelengths having different reference wavelengths; the reference wavelength is a wavelength when the phase difference between the transmitted light in the first region and the transmitted light in the second region is 180 degrees. The exposure device according to item 1 of the scope of patent application, wherein the phase shift mask is illuminated with the illumination wavelength changed to a wavelength different from the reference wavelength, and the phase shift mask is illuminated according to the The projection optical system of the reference wavelength and the changed illumination wavelength and the spherical aberration changes a pattern image of the phase shift mask onto the substrate. The exposure device according to item 1 of the scope of patent application, wherein the control unit controls the use so that a change in depth of focus caused by shortening the illumination wavelength by 30 nm or more by the first changing unit is reduced. Changing the spherical aberration by the second changing unit. The exposure device according to item 1 of the scope of patent application, further comprising a light source that emits light including a plurality of bright-line spectra, and the first changing unit transmits the light-spectrum including the plurality of bright-line spectra emitted from the light source. The wavelength of the light is narrowed to change the illumination wavelength. The exposure device according to claim 1, wherein the control unit is based on information indicating a change amount of a spherical aberration of the projection optical system with respect to a difference between the reference wavelength and the changed illumination wavelength. To control the second change section. The exposure device according to claim 5 in the patent application scope, wherein the control unit changes the illumination wavelength to each of a plurality of wavelengths different from each other, and determines a focal depth for each of the plurality of wavelengths. And obtain the information by maximizing the spherical aberration of the projection optical system. The exposure device according to item 1 of the scope of patent application, wherein the second changing unit changes a spherical aberration of the projection optical system by moving an optical element arranged on a light path in the projection optical system. . The exposure device according to item 1 of the scope of patent application, wherein the second changing unit changes a spherical aberration of the projection optical system by replacing an optical element arranged on a light path in the projection optical system. The exposure device according to item 7 of the scope of patent application, wherein the projection optical system includes a concave mirror and a convex mirror, and the optical element includes a meniscus lens disposed on a light path between the concave mirror and the convex mirror. . The exposure device according to item 1 of the scope of patent application, further comprising a third changing unit that changes a defocus amount, and the control unit controls the third change by modifying and controlling the defocus amount after the second changing unit is controlled. unit. An exposure method uses a phase-shift mask and a projection optical system to expose a substrate. The phase-shift mask includes a first region and a second region with mutually different phases of transmitted light at a reference wavelength. The pattern image of the phase shift mask is projected onto the substrate, and includes the following steps: changing an illumination wavelength of light illuminating the phase shift mask to a wavelength different from the reference wavelength; and The reference wavelength and the changed illumination wavelength change a spherical aberration of the projection optical system, thereby correcting a change in focal depth caused by changing the illumination wavelength; the reference wavelength is a transmission in the first region The wavelength at which the phase difference between the light and the transmitted light in the second region is 180 degrees. According to the exposure method according to item 11 of the scope of patent application, it further has the following procedure: the phase shift mask is illuminated with the changed illumination wavelength changed to a wavelength different from the reference wavelength, and used The projection optical system having the spherical aberration changed according to the reference wavelength and the changed illumination wavelength projects a pattern image of the phase shift mask onto the substrate. An exposure method uses a phase shift mask and an exposure device to expose a substrate. The phase shift mask includes a first region and a second region that make phases of transmitted light different from each other at a reference wavelength. The exposure device includes: The first change unit changes the illumination wavelength of the light illuminating the phase shift mask; the projection optical system projects a pattern image of the phase shift mask onto a substrate; the second change unit changes the projection optical system And a control unit that controls the change of the spherical aberration by the second changing unit based on the wavelength change by the first changing unit, and has the following procedure: The reference wavelength and the changed illumination wavelength are controlled to change the spherical aberration by the second changing unit, thereby correcting that the illumination wavelength is changed to the reference by using the first changing unit. A change in focal depth caused by different wavelengths; the reference wavelength is a wavelength when the phase difference between the transmitted light in the first region and the transmitted light in the second region is 180 degrees. According to the exposure method according to item 13 of the scope of patent application, it further has the following procedure: the phase shift mask is illuminated with the changed illumination wavelength changed to a wavelength different from the reference wavelength, and used The projection optical system having the spherical aberration changed according to the reference wavelength and the changed illumination wavelength projects a pattern image of the phase shift mask onto the substrate. An article manufacturing method, comprising the following procedures: exposing a substrate using the exposure device described in any one of claims 1 to 10 of the scope of patent application; and after the exposure is performed in the foregoing procedure, The substrate is developed.