HK1119257A

HK1119257A - Illumination optical system, exposure system, and exposure method

Info

Publication number: HK1119257A
Application number: HK08111088.2A
Authority: HK
Inventors: 修谷津; 裕久田中; 研一村松; 典男小峯; 寿西永; 知行松山; 威人工藤
Original assignee: 株式会社尼康
Priority date: 2002-12-03
Filing date: 2008-10-06
Publication date: 2009-02-27

Description

Optical illumination device, exposure device, and exposure method

The application is application number: 200380104450.5, filing date: a divisional application entitled "optical illumination device, exposure device, and exposure method" on 12/2/2003.

Technical Field

The present invention relates to an optical illumination device, an exposure device and an exposure method, and more particularly, to an exposure device for manufacturing microdevices such as semiconductor devices, imaging devices, liquid crystal display devices and thin film magnetic heads by photolithography.

Background

In such a typical exposure apparatus, a light beam emitted from a light source passes through a fly eye lens as an optical integrator to form a secondary light source as a substantial surface light source composed of a plurality of light sources. The light beam from the secondary light source is restricted by a diaphragm disposed in the vicinity of the focal plane on the rear side of the fly's eye lens, and then enters the focusing lens.

The light beams condensed by the focusing lens are overlappingly illuminated onto the mask on which the predetermined pattern has been formed. The light passing through the mask pattern is imaged on the wafer through the projection optical system. In this way, the mask pattern is projection-exposed (transferred) onto the wafer. In addition, since the pattern formed on the mask has a high degree of integration, it is necessary to transfer the fine pattern onto a wafer to obtain a uniform illuminance distribution on the wafer.

A technique of forming a circular secondary light source on the rear focal plane of the fly-eye lens and changing the size thereof to change the coherence (coherence) σ of illumination (σ value is the aperture diameter of the aperture/the pupil diameter of the projection optical system, or σ value is the numerical aperture on the exit side of the illumination optical system/the numerical aperture on the entrance side of the projection optical system) is attracting attention. In addition, attention is paid to a technique of forming a secondary light source in a shape of a circular band or a quadrupole on a rear focal plane of the fly-eye lens to improve a depth of focus and a resolution of the projection optical system.

In the conventional exposure apparatus described above, in accordance with the characteristics of the mask pattern, general circular illumination is performed by the circular secondary light source, and deformed illumination (rim illumination or quadrupole illumination) is performed by the annular or quadrupole secondary light source. However, according to the mask pattern characteristics, the mask is generally illuminated with unpolarized light without changing the polarization state of the light illuminating the mask. Therefore, the necessary illumination conditions cannot be realized to faithfully transfer the photomask pattern

In view of the above-described problems, it is an object of the present invention to provide an optical illumination device, for example, mounted in an exposure apparatus, which can change the polarization state of illumination light while suppressing light loss according to the characteristics of a mask pattern, and can implement appropriate illumination conditions.

Another object of the present invention is to provide an exposure apparatus and an exposure method using an optical illumination device that can change the polarization state of illumination light according to the characteristics of a mask pattern, thereby performing excellent exposure under appropriate illumination conditions according to the characteristics of the mask pattern.

Disclosure of Invention

In order to solve the above problem, a first aspect of the present invention provides an optical illumination device including a light source unit for providing linearly polarized light and irradiating an irradiated surface with light emitted from the light source unit. The optical illumination device includes a polarization state switching means disposed in an optical path between the light source unit and the surface to be illuminated, and configured to switch a polarization state of light illuminating the surface to be illuminated between a specific polarization state and a non-polarization state.

The polarization state switching means comprises a depolarizer which can be freely inserted into and removed from the illumination light path to depolarize the incident linearly polarized light as required.

According to the first aspect of the present invention, when the specific polarization state is a linear polarization state, the polarization state switching means can change the polarization plane of the linear polarization. In addition, the polarization state switching means may include a phase member for changing the polarization plane of the incident linearly polarized light according to the requirement. In this case, the phase member has an 1/2-wavelength plate, and the crystal optical axis thereof is freely rotatable about the optical axis of the optical illumination device.

In addition, according to the first aspect, the depolarizer includes a crystal prism whose crystal optical axis is freely rotatable around the optical axis of the optical illumination device. In addition, the depolarizer further comprises a polarization beam splitter and a reflection system. The reflection system is to make the optical path of the light passing through the polarization beam splitter substantially coincident with the optical path of the light finally reflected by the polarization beam splitter, and to make the light reflected by the polarization beam splitter reflect on the plane a plurality of times and then return to the polarization beam splitter. The polarization beam splitter and the reflection system are freely rotated around the optical axis of the optical illumination device.

In addition, according to the first aspect, the depolarizer further includes a polarization beam splitter and a reflective system. The reflection system is to make the optical path of the light passing through the polarization beam splitter substantially coincident with the optical path of the light finally reflected by the polarization beam splitter, and to make the light reflected by the polarization beam splitter reflect on the plane a plurality of times and then return to the polarization beam splitter. The polarization beam splitter and the reflection system can be integrally inserted into and separated from the illumination light path.

In addition, according to the first aspect, the polarization state switching means further includes a second phase material for converting the incident elliptically polarized light into linearly polarized light. The second phase member further includes an 1/4 wavelength plate, and the 1/4 wavelength plate is rotatable around the optical axis of the optical illumination device.

In addition, according to the first aspect, the light transmitting member formed of a cubic system is disposed in the optical path between the light source unit and the polarization state switching means, and the light traveling direction is set to be closer to <111> or <100> than the crystal orientation <110 >. In this case, in the light transmitting member formed of a cubic system disposed in the optical path between the polarization state switching means and the irradiated surface, the light traveling direction is set to be closer to <111> or <100> than the crystal orientation <110 >.

The light transmitting member further includes an optical member fixedly positioned in the optical path, wherein an optical axis of the optical member is set to substantially coincide with a crystal orientation <111> or a crystal orientation <100 >. The light transmitting member includes a rectangular prism as a back mirror, wherein the incident surface and the exit surface of the rectangular prism are set to substantially coincide with the {100} crystal plane, and the reflection surface of the rectangular prism is set to substantially coincide with the {110} crystal plane. In addition, the light transmitting member further includes a parallel plate disposed in the light path to be inclined with respect to the optical axis, so that the light incident along the optical axis moves in parallel, wherein the optical axis of the parallel plate is set to substantially coincide with the crystal orientation <100 >.

In addition, according to the first aspect, the optical illumination device further includes an illumination pupil distribution forming means for forming a predetermined light intensity distribution on or near the pupil plane of the optical illumination device based on the light beam emitted from the light source section; a changing means for changing at least one of a shape and a size of the predetermined light intensity distribution; and a light guide optical system that guides the light beam emitted from the predetermined light intensity distribution to the surface to be irradiated. In this case, the polarization state switching means changes the polarization state of the light for illuminating the surface to be irradiated according to a change in at least one of the shape and the size of the predetermined light intensity distribution. The polarization state switching means switches the polarization state of the light used to illuminate the surface to be illuminated between a linear polarization state and a non-polarization state in accordance with a change in at least one of the shape and the size of the predetermined light intensity distribution.

In addition, according to the first aspect, the polarization state switching means is based on a change in at least one of a shape and a size of the predetermined light intensity distribution, and the S1 component of the stecke parameter of the light in the specific polarization state satisfies the following condition: is less than or equal to 0.6 and is S1. In addition, in the unpolarized state, the S1 and S2 components of the steckel parameter of light satisfy the following condition: | S1| is less than or equal to 0.1 and | S2 | is less than or equal to 0.1. The optical illumination device further includes polarization state variation correction means disposed in an optical path between the light source unit and the surface to be irradiated for correcting variation in the polarization state on the surface to be irradiated. In this case, the polarization state variation correcting means further includes a polarization monitor disposed in an optical path between the polarization state switching means and the irradiated surface, for detecting the polarization state of the light; and a control unit for controlling the polarization state switching means according to the output of the polarization monitor.

In addition, according to the first aspect, the polarization state switching means further includes an 1/2 wavelength plate having a crystal optical axis freely rotating around the optical axis of the optical illumination device; and an 1/4 wavelength plate having a crystal optical axis that freely rotates around the optical axis of the optical illumination device. When the optical axis of the crystal of the 1/4 wavelength plate and the optical axis of the crystal of the 1/2 wavelength plate are changed, the control unit positions the angular position of the optical axis of the crystal of the 1/4 wavelength plate at a desired position so that the incident elliptically polarized light is converted into linearly polarized light, and positions the angular position of the optical axis of the crystal of the 1/2 wavelength plate at a desired position so that the incident linearly polarized light is converted into linearly polarized light having a plane of polarization in a predetermined direction, in response to the detection result of the polarization monitor. In this case, when the crystal optical axis of the 1/4 wavelength plate is changed, the controller positions the angle position of the crystal optical axis of the 1/4 wavelength plate at a first angle position at which the contrast of the change in the smith parameter S1 component in the detection result becomes approximately maximum, and positions the angle position of the crystal optical axis of the 1/2 wavelength plate at a second angle position at which the contrast of the smith parameter S1 component in the detection result becomes approximately maximum or minimum when the crystal optical axis of the 1/2 wavelength plate is changed in a state in which the crystal optical axis of the 1/4 wavelength plate is set at the first angle position.

In addition, according to the first type, the polarization monitor further includes a beam splitter disposed in the optical path between the polarization state switching means and the irradiated surface for extracting the reflected light or the transmitted light of the polarization state different from the polarization state of the incident light from the optical path; and a light intensity detector for detecting the intensity of the reflected light or the transmitted light extracted from the optical path by the optical splitter and detecting the polarization state of the incident light to the optical splitter according to the output of the light intensity detector. In this case, the spectroscope has a reflection characteristic or a transmission characteristic such that an intensity ratio Ip/Is between a P-polarization intensity Ip and an S-polarization intensity Is included in the reflected light or the transmitted light satisfies a condition that Ip/Is < 1/2 or Ip/Is > 2.

In the first aspect, the optical illumination device further includes an illumination pupil distribution forming means for forming a predetermined light intensity distribution on the pupil surface or the vicinity of the pupil surface of the optical illumination device in accordance with the light beam emitted from the light source unit, wherein the illumination pupil distribution forming means forms two regions of high light intensity distribution with a gap therebetween along a direction on the surface corresponding to the pupil surface or the vicinity of the pupil surface in the predetermined direction on the illumination target surface, and the polarization state switching means sets the polarization state of the light illuminated from the two regions of high light intensity distribution to the illumination target surface to a linear polarization state having a polarization plane in a direction perpendicular to the predetermined direction. In this case, the two high light intensity partial regions are formed symmetrically to the optical axis of the optical illumination device, wherein a ratio of a diameter Φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter Φ p of the pupil surface with the optical axis as a center is defined as σ o, σ o ═ Φ o/Φ p, where σ o satisfies the following condition: sigma o is more than or equal to 0.7. Further, two high light intensity partial regions are formed symmetrically to the optical axis of the optical illumination device, where σ o is defined as a ratio of a diameter φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter φ p of a pupil surface, and σ i is defined as a ratio φ i/φ p of an inscribed circle diameter φ i and a diameter φ p of a pupil surface inscribing the two high light intensity partial regions, with the optical axis as a center, and 0.5 ≦ σ i/σ o.

A second aspect of the present invention provides an optical illumination device that illuminates an illuminated surface with a specific polarization state according to light emitted from a light source unit.

The optical illumination device includes a light guide means disposed in an optical path between the light source unit and the surface to be irradiated, for guiding light emitted from the light source unit to the surface to be irradiated; and

polarization state variation correcting means disposed in an optical path between the light source unit and the surface to be irradiated for correcting the polarization state variation on the surface to be irradiated.

According to the second aspect, the polarization state variation correction means further includes polarization state adjustment means disposed in the optical path between the light source unit and the surface to be irradiated for adjusting the polarization state on the surface to be irradiated; a polarization monitor disposed in an optical path between the light source unit and the illuminated surface, for detecting a polarization state of the light; and a control unit for controlling the polarization state adjusting means according to the output of the polarization monitor. In this case, the polarization state adjusting means includes an adjustable phase plate disposed in the optical path between the light source section and the polarization monitor. The light guide means includes an optical member having a characteristic of emitting incident light with a polarization state changed. The optical member may be formed of a crystalline optical material.

The third aspect of the present invention provides an optical illumination device, which illuminates an illuminated surface according to light emitted from a light source.

The optical illumination device comprises a light guide means arranged in an optical path between a light source part and an illuminated surface for guiding light emitted from the light source part to the illuminated surface;

and a polarization state stabilizing means disposed in an optical path between the light source unit and the surface to be irradiated for stabilizing a polarization state on the surface to be irradiated.

According to the third aspect, the polarization state stabilizing means may further include polarization state adjusting means disposed in the optical path between the light source unit and the irradiated surface for adjusting the polarization state on the irradiated surface; a polarization monitor disposed in an optical path between the light source unit and the illuminated surface, for detecting a polarization state of the light; and a control unit for controlling the polarization state adjusting means according to the output of the polarization monitor. In this case, the polarization state adjusting means includes an adjustable phase plate disposed in the optical path between the light source section and the polarization monitor. The light guide means includes an optical member having a characteristic of emitting incident light with a polarization state changed. The optical member is formed of a crystalline optical material.

In addition, according to the third aspect, the polarization state stabilizing means includes a light transmitting member which is disposed in the optical path between the light source portion and the irradiated surface and is formed of a cubic crystal material. In this case, the light traveling direction of the light transmitting member is preferably set closer to the crystal orientation <111> or the crystal orientation <100> than the crystal orientation <110 >. In addition, the light transmitting member has an optical member fixedly positioned in the optical path, and the optical axis of the optical member is preferably set to substantially coincide with the crystal orientation <111> or the crystal orientation <100 >. Alternatively, the light transmitting member may have a rectangular prism as a back mirror, and preferably, the incident surface and the exit surface of the rectangular prism may be set to substantially coincide with the {100} crystal plane, and the reflection surface may be set to substantially coincide with the {110} crystal plane. Alternatively, the light transmitting member has a parallel plate, and is disposed in the optical path so as to be inclined with respect to the optical axis, so that the light incident along the optical axis is moved in parallel. Preferably, the optical axis of the parallel plate is set to approximately coincide with the crystal orientation <100 >.

In a fourth aspect, the present invention provides a method for adjusting an optical illumination device, wherein the optical illumination device illuminates an illuminated surface with a specific polarization state according to light emitted from a light source.

The adjustment method of the optical illumination device includes a wavelength plate setting step of setting a crystal optical axis of the 1/4 wavelength plate at a predetermined angular position in an illumination optical path of the optical illumination device, and setting a crystal optical axis of the 1/2 wavelength plate at a predetermined angular position in the illumination optical path of the optical illumination device.

The wavelength plate setting step is to set the crystal optical axis of the 1/4 wavelength plate at a desired position based on the detection result of the polarization state of the light detected in the optical path between the polarization state switching means and the irradiated surface when the crystal optical axis of the 1/4 wavelength plate and the crystal optical axis of the 1/2 wavelength plate are changed, convert the incident elliptically polarized light into linearly polarized light, and set the crystal optical axis of the 1/2 wavelength plate at a reference position, convert the incident linearly polarized light into linearly polarized light having a polarization plane in a predetermined direction.

According to the fourth embodiment, when the crystal optical axis of the 1/4 wavelength plate is changed, the crystal optical axis of the 1/4 wavelength plate is set at the first angular position at which the change in the smith parameter S1 component in the detection result is approximately maximized, and when the crystal optical axis of the 1/2 wavelength plate is changed in a state in which the crystal optical axis of the 1/4 wavelength plate is set at the first angular position, the crystal optical axis of the 1/2 wavelength plate is set at the second angular position at which the smith parameter S1 component in the detection result is approximately maximized or minimized. In addition, the adjusting method of the optical illumination device further includes an illumination pupil forming step of forming a predetermined light intensity distribution on or in the vicinity of a pupil surface of the optical illumination device based on the light beam emitted from the light source section; an illumination pupil changing step of changing at least one of a shape and a size of the predetermined light intensity distribution; a wavelength plate resetting step of correcting and setting at least one of the crystal optical axis of the 1/4 wavelength plate and the crystal optical axis of the 1/2 wavelength plate according to a change in at least one of the shape and the size of the predetermined light intensity distribution.

A fifth aspect of the present invention provides an exposure apparatus comprising the optical illumination apparatus according to the first to third aspects or an optical illumination apparatus adjusted by the adjustment method according to the fourth aspect, wherein a predetermined pattern is exposed on a photosensitive substrate disposed on the irradiated surface.

According to a fifth aspect of the present invention, the exposure apparatus further includes a projection optical system disposed in an optical path between a first setting surface set by the predetermined pattern and a second setting surface set by the photosensitive substrate, for forming a predetermined pattern image on the second setting surface; pupil intensity distribution forming means for forming a predetermined light intensity distribution at a position at or near the pupil and the conjugate position of the projection optical system; and pupil intensity distribution changing means for changing at least one of the shape and the size of the predetermined light intensity distribution. In this case, the exposure apparatus further includes a polarization state changing means disposed in an optical path between the light source section and the illuminated surface for changing a polarization state of the light illuminated to the illuminated surface, wherein the pupil intensity distribution changing means changes at least one of a shape and a size of the predetermined light intensity distribution in accordance with the predetermined pattern characteristic. The polarization state changing means changes the polarization state of the light to be illuminated on the surface to be illuminated according to a change in at least one of the shape and the size of the predetermined light intensity distribution. In this case, the polarization state changing means includes polarization state switching means for switching the polarization state of the light illuminating the surface to be irradiated between a specific polarization state and a non-polarization state. The polarization state switching means switches between a specific polarization state and the non-polarization state according to a change in at least one of the shape and the size of the predetermined light intensity distribution.

In addition, according to the fifth aspect of the present invention, the pupil intensity distribution forming means forms two high light intensity distribution regions at intervals along the pitch direction of the line and space patterns formed on the mask. The polarization state changing means sets the polarization state of the light illuminating the illuminated surface from the two high-light-intensity partial areas to a linear polarization state having a polarization plane in a direction substantially perpendicular to the pitch direction. Alternatively, the pupil intensity distribution forming means forms a high-light-intensity partial region substantially around the optical axis of the optical illumination device, and the polarization state changing means sets the polarization state of light illuminated from the high-light-intensity partial region to the illuminated surface to a linear polarization state having a polarization plane in a direction substantially perpendicular to the pitch direction of the line and space formed on the phase shift mask serving as the mask. In this case, the ratio of the size of the high light intensity partial region and the diameter Φ p of the pupil surface is defined as σ, σ ═ Φ/Φ p, where σ o satisfies the following condition: sigma is less than or equal to 0.4.

A sixth aspect of the present invention provides an exposure method including the optical illumination device according to the first to third aspects or an optical illumination device adjusted by the adjustment method according to the fourth aspect, wherein the exposure method includes an illumination step of illuminating a mask by the optical illumination device.

And an exposure step of exposing a predetermined pattern on the photosensitive substrate disposed on the irradiated surface.

According to a sixth aspect of the present invention, the exposure method may further include a projection step of forming a predetermined pattern image using a projection optical system; a pupil intensity distribution forming step of forming a predetermined light intensity distribution at a position at or near a pupil and a conjugate position of the projection optical system; and a pupil intensity distribution changing step for changing at least one of a shape and a size of the predetermined light intensity distribution. In this case, the pupil intensity distribution changing step further includes changing at least one of a shape and a size of the predetermined light intensity distribution according to the predetermined pattern characteristic, and changing a polarization state of the light illuminated to the illuminated surface according to the change in the at least one of the shape and the size of the predetermined light intensity distribution.

According to a sixth aspect of the present invention, the pupil intensity distribution forming step further includes forming two high light intensity distribution areas at an interval along a pitch direction of the line and space patterns formed on the mask, and setting a polarization state of light illuminating the illuminated surface from the two high light intensity distribution areas to a linear polarization state having a polarization plane in a direction substantially perpendicular to the pitch direction. In this case, the two high light intensity partial regions are formed symmetrically to the optical axis of the optical illumination device, wherein a ratio of a diameter Φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter Φ p of a pupil surface with the optical axis as a center is defined as σ o, σ o ═ Φ o/Φ p, where σ o satisfies the following condition: sigma o is more than or equal to 0.7. In addition, two high light intensity partial regions are formed symmetrically to the optical axis of the optical illumination device, wherein the ratio phi o/phi p of the diameter phi o of a circumscribed circle circumscribing the two high light intensity partial regions and the diameter phi p of a pupil surface with the optical axis as a center is defined as sigma o, and the ratio phi i/phi p of the diameter phi i of an inscribed circle inscribed in the two high light intensity partial regions with the optical axis as a center and the diameter phi of the pupil surface is defined as sigma i, and 0.5 ≦ sigma i/sigma o.

The seventh aspect of the present invention provides an exposure method for exposing a pattern of a mask set on a first surface to a photosensitive substrate disposed on a second surface. The exposure method comprises the following steps:

the first step is as follows: providing linearly polarized light;

the second step is as follows: illuminating the photomask according to the linearly polarized light provided in the first step;

the third step: exposing the pattern of the mask illuminated by the second step onto a photosensitive substrate;

the fourth step: and switching the polarization state of the light on the second surface between a specific polarization state and a non-polarization state, wherein a depolarizer for non-polarization is inserted into or separated from the illumination light path according to the incident linear polarization and the requirement.

According to a seventh aspect of the present invention, the fourth step of the exposure method may further include a step of changing a polarization plane of the linear polarization. In addition, the third step of the exposure method may further include: forming a pattern of a mask onto the second face using a projection optical system; forming a predetermined light intensity distribution at a position conjugate to a pupil of the projection optical system or a position in the vicinity thereof; changing at least one of a shape and a size of the predetermined light intensity distribution; and changing the polarization state of the light illuminating the illuminated surface according to a change in at least one of the shape and the size of the predetermined light intensity distribution.

The eighth aspect of the present invention provides an exposure method for exposing a pattern of a mask set on a first surface to a photosensitive substrate disposed on a second surface. The exposure method comprises the following steps:

the first step is as follows: providing light;

the second step is as follows: illuminating the mask according to the light provided in the first step;

the third step: exposing the pattern of the photomask illuminated in the second step onto a photosensitive substrate; and

and a fourth step of correcting a variation in the polarization state of the light on the second surface.

According to an eighth aspect of the present invention, the exposure method further includes a fifth step of detecting a polarization state of the light.

The fourth step further includes a step of adjusting the polarization state on the second surface according to the light polarization state detected in the fifth step.

A ninth aspect of the present invention provides an optical illumination device, which illuminates an illuminated surface with a specific polarization state according to light emitted from a light source.

The optical illumination device comprises a polarization state changing means arranged in an optical path between the light source unit and the surface to be illuminated for changing the polarization state of light illuminating the surface to be illuminated; and

aspect ratio conversion means for changing an aspect ratio of a light intensity distribution formed on an illumination pupil which is substantially in a fourier transform relationship with the surface to be irradiated.

According to a ninth aspect of the present invention, the polarization state changing means may include polarization state switching means for switching the polarization state of the light illuminating the irradiated surface between a specific polarization state and a non-polarization state. Further, according to the ninth embodiment of the present invention, the aspect ratio changing means is disposed at or near a position substantially in a fourier transform relationship with the irradiated surface, and includes an optical element group having a function of changing the magnification in two directions perpendicular to the irradiated surface.

A tenth aspect of the present invention provides an exposure apparatus comprising the optical illumination device according to the ninth aspect, for exposing a pattern of a mask to a photosensitive substrate disposed on the irradiated surface.

According to the tenth aspect of the present invention, the polarization state changing means changes the polarization state of light according to the pattern characteristics of the mask; the aspect ratio changing means changes the aspect ratio of the light intensity distribution formed on the illumination pupil according to the pattern characteristics of the mask.

An eleventh aspect of the present invention provides an exposure method for exposing a mask pattern set on a first surface to a photosensitive substrate set on a second surface. The exposure method comprises the following steps:

the first step is as follows: providing light of a particular polarization state;

the third step: exposing the mask pattern illuminated in the second step onto a photosensitive substrate;

the fourth step: altering the polarization state of light on the second face;

the fifth step: the aspect ratio of the light intensity distribution formed at the illumination pupil in substantially fourier transform relationship with the second surface is varied.

According to the eleventh aspect, the fourth step changes the polarization state of the light according to the pattern characteristics of the mask. In addition, according to the eleventh aspect, the fifth step changes the light intensity aspect ratio formed on the illumination pupil according to the pattern characteristics of the mask.

A twelfth embodiment of the present invention provides an optical illumination device that irradiates an irradiated surface with light emitted from a light source unit. The optical illumination device includes:

polarized illumination setting means for setting a polarization state of light illuminating the illuminated surface to a specific polarization state; and

and an optical integrator disposed between the light source unit and the surface to be irradiated.

The optical integrator comprises a first one-dimensional cylindrical lens array arranged along a preset first direction at intervals; and a second one-dimensional cylindrical lens array arranged at a pitch along a second direction intersecting the first direction.

According to a twelfth aspect of the present invention, the first and second one-dimensional cylindrical lens arrays are integrally provided on the light-transmissive substrate.

According to a twelfth aspect of the present invention, an optical illumination device includes a plurality of cylindrical lens array plates including first and second one-dimensional cylindrical lens arrays. The cylindrical lens array plates are arranged at intervals along the optical axis direction of the optical illumination device. In addition, the pitch along the first direction of the first one-dimensional cylindrical lens array and the pitch along the second direction of the second one-dimensional cylindrical lens array have at least one pitch of 2mm or less.

A thirteenth aspect of the present invention provides an exposure apparatus comprising the optical illumination device according to the twelfth aspect, wherein the pattern of the mask is exposed onto a photosensitive substrate on which the surface to be irradiated is disposed.

The fourteenth aspect of the present invention provides an exposure method, comprising the steps of: illuminating the mask using the optical illumination device described in the twelfth aspect; and an exposure step of exposing the pattern of the mask onto a photosensitive substrate disposed on the irradiated surface.

Compared with the prior art, the invention has obvious advantages and beneficial effects. Accordingly, the present invention relates to an optical illumination device, an exposure device and an exposure method. The optical illumination device is mounted on an exposure device, for example, and can change the polarization state of illumination light while suppressing light loss according to the characteristics of a mask pattern, thereby implementing appropriate illumination conditions. The light source unit 1 for providing linearly polarized light illuminates an irradiated surface with light emitted from the light source unit (M, W). The optical illumination device has polarization state switching means (10, 20) disposed in an optical path between the light source unit and the surface to be illuminated for switching the polarization state of light illuminating the surface to be illuminated between a specific polarization state and a non-polarization state. The polarization state switching means further has a depolarizer 20 configured to be freely inserted into and removed from the illumination light path and depolarize the incident linearly polarized light as desired.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a schematic structural diagram of an exposure apparatus having an optical illumination apparatus according to an embodiment of the invention.

Fig. 2 is a schematic diagram of the annular secondary light source and the quadrupole secondary light source formed by the annular illumination and the quadrupole illumination.

FIG. 3 is a schematic diagram of a two-pole secondary light source formed by two-pole illumination.

FIG. 4 is a schematic diagram of the phase member and the depolarizer of FIG. 1.

Fig. 5 is a schematic structural diagram of a polarization state switching means according to a first variation.

Fig. 6 is a schematic diagram illustrating a polarization state switching method according to a second variation.

Fig. 7 is a schematic structural diagram of a polarization state switching means according to a third variation.

FIG. 8 is a schematic diagram of a depolarizer of a variation.

Fig. 9 is a schematic view showing an internal configuration of the light beam matching unit disposed between the light source and the polarization state switching means in fig. 1.

Fig. 10 is an explanatory view showing a crystal orientation of fluorite.

Fig. 11 is a diagram showing an example of an 1/4 wavelength plate attached to a polarization state switching means for converting elliptical polarization into linear polarization.

Fig. 12 is a flow chart of a method of fabricating a semiconductor device as a microelectronic device.

FIG. 13 is a flow chart of a method of fabricating a liquid crystal display device as a microelectronic device.

FIG. 14 is a schematic diagram of a mask illuminated by linearly polarized light in dipole illumination.

FIG. 15 is a schematic diagram showing the illumination of a mask with linearly polarized light in a circular illumination.

FIG. 16 is a schematic diagram of the exposure apparatus shown in FIG. 1 with a polarization monitor for detecting the polarization state of the illumination light.

Fig. 17 is a perspective view illustrating an internal structure of the polarization monitor of fig. 16.

FIG. 18 is a flowchart illustrating a method for adjusting the crystal optical axes of the 1/4 wavelength plate and the 1/2 wavelength plate of the polarization state switching means in FIG. 11.

FIG. 19 is a graph showing the change in output of a polarization monitor at various angular positions for the crystallographic optical axis of the 1/2 wavelength plate when the crystallographic optical axis of the 1/4 wavelength plate is fixed at the-45 degree standard angular position.

FIG. 20 is a graph showing the change in output of the polarization monitor at each angular position of the crystal optical axis of the 1/2 wavelength plate in a state where the crystal optical axis of the 1/4 wavelength plate is set at each angular position.

FIG. 21 is a graph showing the output versus change of a polarization monitor for the state of the crystal optical axis of the 1/4 wavelength plate at each angular position.

FIG. 22 is a graph showing the change in output of a polarization monitor at various angular positions for the crystal optical axis of the 1/2 wavelength plate when the crystal optical axis of the 1/4 wavelength plate is fixed at a first angular position for converting elliptically polarized light to linearly polarized light.

Fig. 23 is a schematic diagram of an exposure apparatus having an illumination pupil distribution forming means with a structure different from that of fig. 1 or 16.

Fig. 24 is a schematic diagram showing the structure of the axicon prism optical system arranged in the optical path between the front lens group and the rear lens group of the telephoto lens in fig. 23.

FIG. 25 is an illustration of the use of axicon prism optics for the secondary light source formed in the wheel illumination of the variation of FIG. 23.

Fig. 26 is an explanatory view showing the operation of the zoom lens for the secondary light source formed in the belt illumination of the variation of fig. 23.

Fig. 27 is a schematic diagram showing the structure of the first cylindrical lens pair and the second cylindrical lens pair arranged in the optical path between the front lens group and the rear lens group of the telephoto lens in fig. 23.

FIG. 28 is a diagram illustrating the operation of a first cylindrical lens pair and a second cylindrical lens pair with respect to a secondary light source formed in the belt illumination of the variation of FIG. 23.

FIG. 29 is a diagram illustrating the operation of a first cylindrical lens pair and a second cylindrical lens pair with respect to a secondary light source formed in the belt illumination of the variation of FIG. 23.

FIG. 30 is a diagram illustrating the operation of a first cylindrical lens pair and a second cylindrical lens pair with respect to a secondary light source formed in the belt illumination of the variation of FIG. 23.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, methods, steps, features and effects of the optical illumination apparatus, the exposure apparatus and the exposure method according to the present invention will be made with reference to the accompanying drawings and preferred embodiments.

Fig. 1 is a schematic diagram showing an exposure apparatus having an optical illumination apparatus according to an embodiment of the present invention. As shown in fig. 1, the direction of the normal line of the wafer W along the photosensitive substrate is set as the Z-axis, the direction parallel to the drawing plane of fig. 1 on the surface of the wafer W is set as the Y-axis, and the direction perpendicular to the drawing plane of fig. 1 on the surface of the wafer W is set as the X-axis. In fig. 1, the optical illumination device illuminates the belt for setting.

The exposure apparatus of the present embodiment includes a laser light source 1 for supplying exposure light (illumination light). As the laser light source 1, for example, a KrF excimer laser light source which supplies light having a wavelength of 248nm, an ArF excimer laser light source which supplies light having a wavelength of 193nm, or the like can be used. The substantially parallel light beam emitted from the laser light source 1 in the Z direction has a cross section extending in the X direction into an elongated rectangle, and is incident on a light diffuser (beam expander)2 constituted by a pair of lenses 2a, 2 b. Each lens 2a, 2b has negative and positive refractive power, respectively, in the plane of the drawing of fig. 1 (YZ plane). Therefore, the light beam incident on the optical diffuser 2 is expanded in the drawing of fig. 1 to be shaped into a light beam having a predetermined rectangular cross section.

The substantially parallel light beam transmitted through the optical diffuser 2 serving as a shaping optical system is deflected in the Y direction by the deflecting mirror 3, and then enters the afocal zoom lens (afocal zoom) 5 via the phase member 10, the depolarizer (depolarizing element) 20, and the diffractive optical element 4. The structure and function of the phase member 10 and the depolarizer 20 will be described in detail below. In general, a diffractive optical element has a step structure in which a left-right interval (pitch) of the wavelength of exposure light (illumination light) is formed on a substrate, and has a function of deflecting an incident beam to a predetermined angle. Specifically, when a parallel light beam having a rectangular cross section is incident, the diffractive optical element 4 has a function of forming a circular light intensity distribution on its far field (far field) or fraunhofer diffraction area.

Therefore, the light beam passing through the diffractive optical element 4 forms a circular light intensity distribution, i.e., a light beam having a circular cross section, at the pupil position of the telephoto zoom lens 5. The diffractive optical element 4 is constructed so as to be retractable from the illumination optical path. The telephoto zoom lens 5 is configured to continuously change magnification within a predetermined range while maintaining a telephoto system (non-focal optical system). The light beam transmitted through the telephoto zoom lens 5 enters the belt illumination diffractive optical element 6. The telephoto zoom lens 5 substantially connects the emission origin of the diffractive optical element 4 and the diffractive surface of the diffractive optical element 6 to each other in an optical conjugate. The numerical aperture of a point on the diffraction surface of the diffractive optical element 6 or a surface near the diffraction surface changes so as to be dependent on the magnification of the telephoto zoom lens 5.

When the parallel light beam enters, the diffractive optical element for wheel illumination 6 has a function of forming a ring-shaped light intensity distribution in its far field. The diffractive optical element 6 is configured to be freely inserted into and removed from the illumination light path, and the quadrupole illumination diffractive optical element 60, the circular illumination diffractive optical element 61, the X-direction two-pole illumination diffractive optical element 62, the Y-direction two-pole illumination diffractive optical element 63, and the like are configured to be switchable with each other. The structures and functions of the quadrupole illumination diffractive optical element 60, the circular illumination diffractive optical element 61, the X-direction two-pole illumination diffractive optical element 62, and the Y-direction two-pole illumination diffractive optical element 63 will be described below.

The light beam passing through the diffractive optical element 6 is incident on the zoom lens 7. An incident surface of a microlens array (or fly-eye lens) 8 is positioned near a rear focal plane of the zoom lens 7. The microlens array 8 is an optical element composed of a plurality of microlenses having positive refractive power arranged in a row and densely arranged. Generally, a microlens array is constructed by, for example, etching a parallel panel to form microlens groups.

Each of the microlenses constituting the microlens array is smaller than each of the lens elements constituting the fly-eye lens. In addition, unlike fly-eye lenses constituted by lens elements that are isolated from each other, a microlens array is formed by integrally forming a plurality of microlenses (micro refractive surfaces) without being isolated from each other. However, the microlens array is a wavefront-dividing type optical integrator, similar to a fly-eye lens, in that lens elements having positive refractive power are arranged in a vertical and horizontal manner.

As described above, the light flux of circular light intensity formed at the pupil position of the telephoto zoom lens 5 by passing through the diffractive optical element 4 is emitted from the telephoto zoom lens 5, and then, becomes light fluxes having various angle components, and enters the diffractive optical element 6. In other words, the diffractive optical element 4 constitutes an optical integrator having an angular beam shaping function. On the other hand, when the parallel light beam is incident, the diffractive optical element 6 functions as a light beam conversion element that forms a circular light intensity distribution in its far field. Therefore, the light flux transmitted through the diffractive optical element 6 forms a circular-band-shaped field centered on, for example, the optical axis AX on the rear focal plane of the zoom lens 7 (also on the incident surface of the microlens array).

The outer diameter of the annular field formed on the incident surface of the microlens array 8 is changed depending on the focal length of the zoom lens 7. In this way, the zoom lens 7 substantially connects the diffractive optical element 5 and the incident surface of the microlens array 8 in a fourier transform relationship. The light flux incident on the microlens array 8 is divided two-dimensionally, and as shown in fig. 2A, a plurality of light sources (hereinafter referred to as secondary light sources) in a band shape similar to the field of illumination formed by the incident light flux are formed on the rear focal plane of the microlens array 8.

The light beam emitted from the belt-like secondary light source formed on the focal plane on the rear side of the microlens array 8 is superposed and illuminated onto the mask M on which the predetermined pattern has been formed, after being condensed by the focusing optical system 9. The light beam passing through the pattern of the photo mask M passes through the projection optical system PL, and an image of the mask pattern is formed on the wafer W of the photosensitive substrate. Accordingly, the pattern of the mask M is exposed one by one to each exposure area on the wafer W by performing the entire exposure or the scanning exposure on the plane (XY plane) perpendicular to the optical axis AX of the projection optical system PL while driving and controlling the wafer W two-dimensionally.

In the present embodiment, when the magnification of the telephoto zoom lens 5 is changed, the center height (the distance from the optical axis AX of the circular center line) d0 of the belt-shaped secondary light source does not change, and only its width (1/2 of the difference between the outer diameter (diameter) and the inner diameter (diameter)) w0 changes. That is, by changing the magnification of the afocal zoom lens 5, the size (outer diameter) of the belt-like secondary light source and its shape (belt ratio: inner diameter/outer diameter) can be changed simultaneously.

Further, when the focal length of the zoom lens 7 is changed, the rim ratio of the rim-like secondary light source is not changed, and the center height d0 and the width w0 are changed simultaneously. That is, by changing the focal length of the zoom lens 7, the outer diameter can be changed without changing the rim ratio of the rim-shaped secondary light source. As described above, in the present embodiment, by appropriately changing the magnification of the telephoto zoom lens 5 and the focal length of the zoom lens 7, it is possible to change only the rim ratio of the rim-shaped secondary light source without changing the outer diameter of the rim-shaped secondary light source.

In addition, instead of the diffractive optical element 6, the diffractive optical element 60 is set in the illumination optical path, so that quadrupole illumination can be performed. When the parallel light beam enters, the quadrupole illumination diffractive optical element 60 has a function of forming a four-point-like light intensity distribution in the far field. Therefore, the light beam passing through the diffractive optical element 60 forms a quadrupole field consisting of four circular fields centered on the optical axis AX on the incident surface of the microlens array 8. Therefore, as shown in fig. 2A, a quadrupole secondary light source having the same field as that formed on the incident surface is also formed on the rear focal plane of the microlens array 8.

In the quadrupole illumination, as in the case of the rim illumination, the ratio between the outer diameter (the diameter of the circumscribed circle of the four circular surface light sources) Do of the quadrupole secondary light source and the rim (the diameter Di of the inscribed circle of the four circular surface light sources/the diameter Do of the circumscribed circle of the four circular surface light sources) can be changed at the same time by changing the magnification of the telephoto zoom lens 5. In addition, by changing the focal length of the zoom lens 7, the outer diameter of the quadrupole secondary light source can be changed without changing the duty ratio thereof. Therefore, by appropriately changing the magnification of the telephoto zoom lens 5 and the focal length of the zoom lens 7, it is possible to change only the duty ratio of the quadrupole secondary light source without changing the outer diameter thereof.

In addition, by retracting the diffractive optical element 4 from the illumination optical path and setting the diffractive optical element 61 for circular illumination in the illumination optical path instead of the diffractive optical element 6 or 60, the general circular illumination can be performed. In this case, a light flux having a rectangular cross section along the optical axis AX is incident on the afocal zoom lens 5. The light flux incident on the telephoto zoom lens 5 is enlarged or reduced according to its magnification, and the light flux having a rectangular cross section exits the telephoto zoom lens 5 along the optical axis AX and enters the diffractive optical element 61.

As in the case of the diffractive optical element 4, when a parallel light flux having a rectangular cross section is incident, the diffractive optical element 61 for circular illumination has a function of forming a circular light intensity distribution in its far field. Therefore, the circular light flux formed by the diffractive optical element 61 passes through the zoom lens 7, and a circular field centered on the optical axis AX is formed at the incident surface of the microlens array 8. As a result, a circular secondary light source centered on the optical axis AX is also formed at the rear focal plane of the microlens array 8. In this case, by changing the magnification of the afocal zoom lens 5 or the focal point of the zoom lens 7, the outer diameter of the circular secondary light source can be appropriately changed.

Then, by setting the diffractive optical element 62 in the illumination optical path instead of the diffractive optical element 6, 60, or 61, the X-direction dipole illumination can be performed. When the parallel light beams are incident, the X-direction two-pole illumination diffractive light unit 62 has a function of forming two-point-like light intensity distributions spaced apart from each other in the X direction in its far field. Therefore, the light beam passing through the diffractive optical element 62 forms a dipole-shaped field on the incident surface of the microlens array 8, which is formed by two circular fields spaced apart by a distance along the X direction with the optical axis AX as the center, for example. As a result, as shown in fig. 3A, a two-pole secondary light source is formed along the X direction also on the rear focal plane of the microlens array 8, similarly to the field formed on the incident surface.

In addition, by setting the diffractive optical element 63 in the illumination optical path instead of the diffractive optical element 6, 60, 61, or 62, it is possible to perform the Y-direction dipole illumination. When the parallel light beam is incident, the diffraction light unit 63 for Y-direction two-pole illumination has a function of forming two-point-like light intensity distributions at a distance in the Z direction (corresponding to the Y direction on the mask and the wafer) in its far field. Therefore, the light beam passing through the diffractive optical element 63 forms a dipole-shaped field on the incident surface of the microlens array 8, which is formed by two circular fields spaced apart by a distance along the Z direction, for example, with the optical axis AX as the center. As a result, as shown in fig. 3B, a two-pole secondary light source is formed along the Z direction also on the rear focal plane of the microlens array 8, as in the field formed on the incident surface.

In the case of the two-pole illumination as well as the case of the four-pole illumination, the outer diameter do of the two-pole secondary light source (circumscribed circle diameter of the two circular surface light sources) and the rim-to-belt ratio (inscribed circle diameter di of the two circular surface light sources/circumscribed circle diameter of the two circular surface light sources) can be changed together by changing the magnification of the telephoto zoom lens 5. In addition, by changing the focal length of the zoom lens 7, the outer diameter of the diode-shaped secondary light source can be changed without changing the duty ratio thereof. As a result, by appropriately changing the magnification of the telephoto zoom lens 5 and the focal length of the zoom lens 7, it is possible to change only the duty ratio of the diode-shaped secondary light source without changing the outer diameter thereof.

FIG. 4 is a schematic diagram of the phase member and the depolarizer of FIG. 1. Referring to fig. 4, the phase member 10 is configured as an 1/2 wavelength plate whose crystal optical axis can freely rotate around the optical axis AX. On the other hand, the depolarizer 20 is composed of a wedge-shaped crystal prism 20a and a wedge-shaped crystal prism 20b having a shape complementary to the crystal prism 20 a. The quartz prism 20a and the quartz prism 20b are a prism assembly integrally configured, and can be freely inserted into and removed from the illumination optical path. When an ArF excimer laser light source is used as the laser light source 1, the polarization degree of the light emitted from the laser light source is generally 95% or more, and thus substantially linearly polarized light enters the 1/2 wavelength plate 10.

When the crystal optical axis of the 1/2 wavelength plate 10 is set to 0 degree or 90 degrees with respect to the plane of polarization of the incident linear polarization, the linear polarization incident on the 1/2 wavelength plate passes through without changing the plane of polarization. When the crystal optical axis of the 1/2 wavelength plate 10 is set to 45 degrees with respect to the plane of polarization of the incident linear polarization, the linear polarization incident on the 1/2 wavelength plate is converted into linear polarization whose plane of polarization is changed by only 90 degrees. When the crystal optical axis of the crystal prism 20a is set to 45 degrees with respect to the polarization plane of the incident linear polarization, the linear polarization incident on the crystal prism 20a is converted into light in a non-polarized state (non-polarized).

In the present embodiment, when the depolarizer 20 is positioned in the illumination light path, the crystal optical axis of the crystal prism 20a is set to 45 degrees with respect to the polarization plane of the incident linear polarization. In other words, when the crystal optical axis of the crystal prism 20a is set to 0 degree or 90 degrees with respect to the polarization plane of the incident linear polarization, the linear polarization incident to the crystal prism 20a passes through directly without changing the polarization plane. When the crystal optical axis of the 1/2 wavelength plate 10 is set to 22.5 degrees with respect to the plane of polarization of the incident linear polarization, the linear polarization incident on the 1/2 wavelength plate 10 is converted into light in an unpolarized state, which includes a linear polarization component in which the plane of polarization passes without being changed and a linear polarization component in which the plane of polarization is changed by only 90 degrees.

As described above, in the present embodiment, the linearly polarized light emitted from the laser light source 1 is incident on the 1/2 wavelength plate 10. However, for the sake of simplicity of the following description, P-polarized (linearly polarized with a polarization plane in the Z direction at the position of the 1/2 wavelength plate in fig. 1, hereinafter referred to as Z-polarized) light is incident on the 1/2 wavelength plate 10. When the depolarizer 20 is positioned in the illumination light path, the angle of the crystal optical axis of the 1/2 wavelength plate 10 with respect to the plane of polarization of the incident P-polarization (Z-direction polarization) is set to 0 degree or 90 degrees, and the P-polarized (Z-direction polarization) light incident on the 1/2 wavelength plate 10 passes directly without changing its plane of polarization and is incident on the crystal prism 20 a. Since the angle of the crystal optical axis of the crystal prism 20a with respect to the polarization plane of the incident P-polarization (Z-polarization) is set to 45 degrees, the P-polarization (Z-polarization) light incident on the crystal prism 20a is converted into non-polarized light. The light unpolarized by the crystal prism 20a passes through a crystal prism 20b serving as a compensator for compensating the traveling direction of the light, and illuminates the mask M (and hence the wafer W) in an unpolarized state. On the other hand, when the angle formed by the crystal optical axis of the 1/2 wavelength plate 10 with respect to the polarization plane of the incident P-polarization (Z-polarization) is set to 45 degrees, the polarization plane of the P-polarization (Z-polarization) light incident on the 1/2 wavelength plate 10 is changed by 90 degrees to S-polarization (linearly polarized in the X-direction at the 1/2 wavelength plate position in fig. 1, hereinafter referred to as X-polarization) light, and the light is incident on the crystal prism 20 a. Since the angle of the crystal optical axis of the crystal prism 20a with respect to the polarization plane of the incident S-polarization (X-polarization) is set to 45 degrees, the S-polarization (X-polarization) light incident on the crystal prism 20a is converted into non-polarized light. The mask M is illuminated in an unpolarized state through the quartz prism 20 b.

In contrast, when the polarizer 20 is retracted from the illumination optical path, if the angle formed by the crystal optical axis of the 1/2 wavelength plate 10 with respect to the polarization plane of the incident P-polarization (Z-polarization) is set to 0 degree or 90 degrees, the light of the P-polarization (Z-polarization) incident on the 1/2 wavelength plate 10 passes through without changing the polarization plane thereof, and the reticle M is illuminated with the light of the P-polarization (Z-polarization) state. On the other hand, when the angle formed by the crystal optical axis of the 1/2 wavelength plate 10 with respect to the polarization plane of the incident P-polarization (Z-polarization) is set to 45 degrees, the polarization plane of the P-polarization (Z-polarization) light incident on the 1/2 wavelength plate 10 changes by 90 degrees to S-polarization, and the mask M is illuminated with the S-polarization (X-polarization) light.

As described above, in this embodiment, mask M is illuminated in an unpolarized state by positioning depolarizer 20 in the path of the illumination light. Further, the P-polarization (Z-polarization) is possible by retracting the depolarizer 20 from the illumination light path and setting the angle of the crystal optical axis of the 1/2 wavelength plate 10 to 0 degree or 90 degrees with respect to the polarization plane of the incident P-polarization (Z-polarization). Further, by retracting the depolarizer 20 from the illumination light path and setting the angle formed by the crystal optical axis of the 1/2 wavelength plate 10 with respect to the polarization plane of the incident P-polarization (Z-polarization) to 45 degrees, the mask M can be illuminated in the S-polarization (X-polarization) state.

In other words, in the present embodiment, the polarization state of the light illuminating the mask M (or the wafer W) serving as the irradiated surface can be switched between the linear polarization state and the non-polarization state by the polarization state switching means constituted by the 1/2 wavelength plate 10 and the depolarizer 20. When illuminated with linearly polarized light, it is possible to switch between the P-state and the S-state of polarization (between mutually orthogonal polarization states). Therefore, in the present embodiment, since the light amount loss is suppressed in accordance with the pattern characteristics of the mask M and the appropriate illumination condition is realized by changing the polarization state of the illumination light, it is possible to perform a good exposure in accordance with the appropriate illumination condition realized by the pattern characteristics of the mask M. In particular, when the illumination is performed by linearly polarized light, the linearly polarized light from the light source 1 can be guided to the irradiated surface without substantially losing the amount of light by the polarization state switching means.

Specifically, for example, by setting a two-pole illumination in the X direction and illuminating the mask M with light in a linearly polarized state having a polarization plane along the X direction on the mask M, a very small pattern of a line width in the X direction can be exposed faithfully on a critical layer on the wafer W. Then, for example, by switching to Y-direction dipole illumination and illuminating the mask M with light in a linearly polarized state having a polarization plane in the Y direction on the mask M, a very small pattern of a line width in the X direction can be exposed faithfully on the same critical layer on the wafer W.

Then, after the double exposure of the critical layer is completed, for example, a two-dimensional pattern with a wide line width of the non-critical layer (intermediate layer or rough layer) on the wafer W can be exposed with high throughput by illuminating the mask M with unpolarized light while switching to quadrupole illumination, wheel band illumination, or circular illumination. But this is an example. In general, by setting the appropriate shape or size of the secondary light source according to the characteristics of the mask M and setting the light illuminating the mask M to an appropriate polarization state, good exposure can be performed under appropriate illumination conditions.

In fact, in the case where the P-polarized light is obliquely incident on the wafer W and the case where the S-polarized light is obliquely incident on the wafer W, the scattering on the surface of the photoresist layer formed on the wafer W is different. Specifically, S-polarized light has a higher reflectivity than P-polarized light, so P-polarized light reaches the inside of the photoresist layer deeper than S-polarized light. By utilizing the difference in optical characteristics between P-polarization and S-polarization with respect to the photoresist layer, the polarization state of the illumination light is changed in accordance with the pattern characteristics of the mask M, and thus, a proper illumination condition can be achieved, and a good exposure can be performed under a proper illumination condition.

In the above embodiment, the 1/2 wavelength plate 10 as a phase member for changing the polarization plane of the incident linearly polarized light beam as needed is disposed on the light source side, and the depolarizer 20 for making the incident linearly polarized light beam unpolarized as needed is disposed on the mask side. However, the present invention is not limited to this embodiment, and the same optical action and effect can be obtained by disposing the depolarizer 20 on the light source side and the 1/2 wavelength plate 10 on the light shield side.

In the above embodiment, the quartz prism 20b is used as the compensator for compensating the traveling direction of the light passing through the quartz prism 20 a. However, this is not intended to be limiting. A wedge prism formed of crystal or fluorite, which is a highly durable optical material for KrF excimer laser or ArF excimer laser, can also be used as a compensator. This point is the same for other related variations.

FIG. 5 is a schematic structural diagram showing a polarization state switching means according to a first variation. The polarization switching means shown in the first modification of fig. 5 has a similar configuration to that of the embodiment of fig. 4. However, the depolarizer 20 shown in fig. 4 is configured to be freely insertable into and detachable from the illumination optical path, and in the first modification shown in fig. 5, the crystal prism 20a and the crystal prism 20b constituting the depolarizer 20 are configured to be integrally rotatable around the optical axis AX. The crystal optical axis of the crystal prism 20a is a point of substantial difference that it freely rotates around the optical axis AX. Next, the variation of fig. 5 will be described with emphasis on differences from the embodiment of fig. 4.

In the modification 1, when the angle of the crystal optical axis of the 1/2 wavelength plate 10 with respect to the incident P-polarized (Z-polarized) polarization plane is positioned at 0 degree or 90 degrees, the P-polarized (Z-polarized) light incident on the 1/2 wavelength plate 10 passes directly through the crystal prism 20a without changing its polarization plane, and enters the crystal prism 20 a. At this time, when the angle of the crystal optical axis of the crystal prism 20a with respect to the incident P-polarized (Z-polarized) polarization plane is set at 45 degrees, the P-polarized (Z-polarized) light incident on the crystal prism 20a is converted into an unpolarized state, and the reticle M is illuminated in the unpolarized state via the quartz prism 20 b. Further, when the angle of the crystal optical axis of the crystal prism 20a with respect to the polarization plane of the incident P-polarization (Z-polarization) is set at 0 degree or 90 degrees, the P-polarization (Z-polarization) light incident on the crystal prism 20a does not change its polarization plane, passes directly with the P-polarization (Z-polarization), and illuminates the mask M in the P-polarization (Y-polarization) state via the crystal prism 20 b.

On the other hand, when the angle of the crystal optical axis of the 1/2 wavelength plate 10 with respect to the incident P-polarized (Z-polarized) polarization plane is set to 45 degrees, the P-polarized (Z-polarized) light incident on the 1/2 wavelength plate 10 changes by 90 degrees to S-polarized (X-polarized) light, and enters the crystal prism 20 a. At this time, when the angle of the crystal optical axis of the crystal prism 20a with respect to the incident P-polarized (Z-polarized) polarization plane is set at 45 degrees, the S-polarized (X-polarized) light incident on the crystal prism 20a is converted into an unpolarized state, and the reticle M is illuminated in the unpolarized state via the quartz prism 20 b. Further, when the angle of the crystal optical axis of the crystal prism 20a with respect to the polarization plane of the incident S polarization (X-direction polarization) is set at 0 degree or 90 degrees, the light of the S polarization (X-direction polarization) incident to the crystal prism 20a does not change its polarization plane, passes directly with the S polarization (X-direction polarization), and illuminates the mask M in the S polarization (X-direction polarization) state via the crystal prism 20 b.

As described above, in the first modification example of fig. 5, the polarization state of the light for illuminating the mask can be switched between the linear polarization state and the non-polarization state by the rotation around the optical axis AX of the 1/2 wavelength plate 10 and the rotation around the optical axis AX of the crystal prism 20 a. In case of illumination with linearly polarized light, it is possible to switch between the P-polarized state and the S-polarized state. In the first modification of fig. 5, the 1/2 wavelength plate 10 is disposed on the light source side and the depolarizer 20 is disposed on the reticle side, but the same optical action and effect can be obtained by disposing the depolarizer 20 on the light source side and disposing the 1/2 wavelength plate 10 on the reticle side.

Fig. 6 is a schematic structural diagram showing a polarization switching means according to a second variation. The polarization switching means shown in the second modification of fig. 6 has a structure similar to that of the polarization switching means of the embodiment of fig. 4. However, in the embodiment of fig. 4, the depolarizer 20 is configured to be freely insertable into and removable from the illumination beam path, whereas the second variation shown in fig. 6 positions the depolarizer 20 in the illumination beam path in a predetermined manner. This is a fundamental difference. Next, the second variation of fig. 6 will be described with an emphasis on the differences from the embodiment of fig. 4.

In the second modification, the crystal optical axis of the crystal prism 20a is positioned at 0 degree or 90 degrees with respect to the polarization plane of the incident P-polarization (Z-polarization). Therefore, when the angle of the crystal optical axis of the 1/2 wavelength plate 10 with respect to the incident P-polarized (Z-polarized) polarization plane is positioned at 0 degree or 90 degrees, the P-polarized (Z-polarized) light incident on the 1/2 wavelength plate 10 passes directly through the crystal prism 20a without changing its polarization plane, and is incident thereon. Since the angle of the crystal optical axis of the crystal prism 20a with respect to the polarization plane of the incident P-polarization (Z-polarization) is positioned at 0 degree or 90 degrees, the P-polarized (Z-polarization) light incident on the crystal prism 20a does not change its polarization plane, passes directly with P-polarization (Z-polarization), and illuminates the mask M in a P-polarized (Y-polarization) state via the quartz prism 20 b.

When the angle of the crystal optical axis of the 1/2 wavelength plate 10 with respect to the polarization plane of the incident P-polarization (Z-polarization) is set at 45 degrees, the P-polarization (Z-polarization) light incident on the crystal prism 20a changes the polarization plane by only 90 degrees to become S-polarization (X-polarization), and then enters the crystal prism 20 a. Since the crystal optical axis of the crystal prism 20a is positioned at an angle of 0 degree or 90 degrees with respect to the polarization plane of the incident S-polarization (X-polarization), the polarization plane of the S-polarization (X-polarization) light incident on the crystal prism 20a does not change, and the S-polarization (X-polarization) passes directly through the crystal prism 20b, and the reticle M is illuminated in the S-polarization state.

When the angle formed by the crystal optical axis of the 1/2 wavelength plate 10 with respect to the incident P-polarized (Z-polarized) polarization plane is set at 22.5 degrees, as described above, the P-polarized (Z-polarized) light incident on the 1/2 wavelength plate 10 does not change the polarization plane, includes the P-polarized (Z-polarized) component whose state passes directly and the S-polarized (X-polarized) component whose polarization plane changes by 90 degrees, and is converted into an unpolarized state and then incident on the crystal prism 20 a. Since the crystal optical axis of the crystal prism 10a is positioned at an angle of 0 degree or 90 degrees with respect to the polarization plane of the incident P-polarization component, the P-polarization (Z-polarization) component and the S-polarization (X-polarization) component incident on the crystal prism 20a pass through the crystal prism 20b without changing the polarization plane and illuminate the mask M in an unpolarized state.

As described above, in the second modification of fig. 6, the polarization state of the light for illuminating the reticle can be switched between the linear polarization state and the non-polarization state by appropriately rotating the 1/2 wavelength plate 10 around the optical axis AX in a state where the depolarizer 20 is fixedly positioned in the illumination optical path. In case of illumination with linearly polarized light, it is possible to switch between the P-polarized state and the S-polarized state. In the second modification of fig. 6, the 1/2 wavelength plate 10 is disposed on the light source side and the depolarizer 20 is disposed on the reticle side, but the same optical action and effect can be obtained by disposing the depolarizer 20 on the light source side and disposing the 1/2 wavelength plate 10 on the reticle side.

Fig. 7 is a schematic structural diagram showing a polarization switching means of a third variation. The polarization switching means shown in the third modification of fig. 7 has a structure similar to that of the polarization switching means of the first modification of fig. 5. However, in the first modification of fig. 5, the polarization switching means is composed of the 1/2 wavelength plate 10 and the depolarizer 20; in contrast, in the third modification shown in fig. 7, the polarization state switching means is basically different in that it is constituted by only the depolarizer that can freely rotate around the optical axis AX. Next, the third variation of fig. 7 will be described with emphasis on differences from the first variation of fig. 5.

In the third modification, when the crystal optical axis of the crystal prism 20a is set at an angle of 45 degrees with respect to the polarization plane of the incident P-polarization (Z-polarization), the P-polarization incident on the crystal prism 20a is changed to the non-polarization state, and the mask M is illuminated in the non-polarization state via the quartz prism 20 b. On the other hand, when the crystal optical axis of the crystal prism 20a is set to an angle of 0 degree or 90 degrees with respect to the polarization plane of the incident P-polarization (Z-polarization), the P-polarization (Z-polarization) light incident on the crystal prism 20a passes through the crystal prism 20b in the P-polarization state (Z-polarization) without changing the polarization plane, and illuminates the mask M in the P-polarization state (Z-polarization).

As described above, in the third modification of fig. 7, the polarization state of the light illuminating the mask M can be switched between the linear polarization state and the non-polarization state by rotating the crystal prism 20a around the optical axis AX as appropriate. In the third modification of fig. 7, the depolarizer 20 is configured to be freely rotatable about the optical axis AX and to be freely insertable into and removable from the illumination optical path, and the same optical action and effect can be obtained even if the reticle M is set to be illuminated with P polarization by retracting the depolarizer 20 from the illumination optical path.

FIG. 8 is a schematic diagram of a modified depolarizer architecture. Although the depolarizer 20 has the structure including the crystal prism 20a in the above-described embodiment and the first to third modifications, the depolarizer 21 may be a polarization beam splitter 21a and a reflection system (21b to 21e) as shown in the modification of fig. 8. Referring to fig. 8, the depolarizer 21 is provided with a polarizing beam splitter 21a arranged in the illumination optical path. Of the light incident on the polarization beam splitter 21a, P-polarized light (the polarization direction thereof is indicated by a double arrow in the figure) passes through the polarization beam splitter 21a with respect to the polarization separation plane of the polarization beam splitter 21 a.

On the other hand, after the S-polarized light (the polarization direction thereof is indicated by dots in the figure) is reflected by the polarization beam splitter 21a with respect to the polarization splitting plane of the polarization beam splitter 21a, it is reflected four times on the plane parallel to the drawing plane of fig. 8 by the action of the reflection system constituted by the four reflection mirrors 21b to 21e, and returns to the polarization beam splitter 21 a. Here, the reflection systems (21b to 21e) are configured so that the optical path of the P-polarized light passing through the polarization beam splitter 21a and the optical path of the S-polarized light finally reflected by the polarization beam splitter 21a are substantially the same. Thus, the P-polarized light passing through the polarization beam splitter 21a and the S-polarized light finally reflected by the polarization beam splitter 21a are emitted from the depolarizer 21 along substantially the same optical path. However, the S-polarized light is delayed in the optical path length of the reflection systems (21b to 21e) with respect to the P-polarized light.

The depolarizer 21 formed of the polarization beam splitter 21a and the reflection systems (21b to 21e) has basically the same optical function as the depolarizer 20 formed of the crystal prism 20a and the crystal prism 20 b. Therefore, the depolarizer 20 of the embodiment and the first to third modifications can be replaced with the depolarizer 21 of the modification of fig. 8. In other words, when the depolarizer 21 is applied to the embodiment of fig. 4, the polarizing beam splitter 21a and the reflective systems (21b to 21e) are configured to be integrally and freely inserted into and removed from the illumination light path.

When the depolarizer 21 is applied to the first modification example of fig. 5 or the third modification example of fig. 7, the polarization beam splitter 21a and the reflection systems (21b to 21e) are configured to be rotatable integrally about the optical axis AX. When the depolarizer 21 is applied to the second modification of fig. 6, the polarization beam splitter 21a and the reflection systems (21b to 21e) are fixedly positioned in the illumination optical path.

In the depolarizer 21 according to the modified example of fig. 8, the optical path length of the reflection systems (21b to 21e) is set to be substantially longer than the interference distance of the illumination light (exposure light), whereby the coherence (interference) of the laser light illuminating the mask M can be reduced, and the spectral contrast on the wafer W can be reduced. Further, the detailed structure of the depolarizer and various modifications thereof, which are applicable to the present invention, including the polarizing beam splitter and the reflection system, can be referred to, for example, Japanese patent application laid-open Nos. 11-174365, 11-312631, 2000-223396 and the like.

Fig. 9 is a schematic diagram illustrating an internal structure of a Beam Matching Unit (BMU) disposed between the light source and the polarization state switching unit in fig. 1. As shown in fig. 9, in the light modulation unit MBU, parallel light supplied from a laser light source 1 (for example, a KrF excimer laser light source or an ArF excimer laser light source) passes through a pair of deflection prisms 31 and a parallel plate 32, and then enters a light diffuser 2. The laser light source 1 is disposed on, for example, a lower substrate a.

Here, at least one of the pair of deflection prisms 31 is configured to be rotatable about the optical axis AX. Therefore, by relatively rotating the pair of deflection prisms 31 around the optical axis AX, the angle of the parallel light flux with respect to the optical axis AX can be adjusted. That is, the pair of deflection prisms 31 is configured as a beam angle adjusting means for adjusting the angle of the parallel beam supplied from the laser light source 1 with respect to the optical axis AX. The parallel plate 32 is supported on a plane perpendicular to the optical axis AX and rotatable about two perpendicular axes.

Therefore, by rotating the parallel plate 32 around each axis, the parallel beam can be moved in parallel with respect to the optical axis AX by being inclined to the optical axis AX. That is, the parallel plate 32 is configured as a beam parallel moving means for moving the parallel beam provided by the laser light source 1 in parallel with respect to the optical axis AX. In this way, the parallel light flux emitted from the laser light source 1 passing through the pair of deflection prisms 31 and the parallel panel 32 passes through the optical diffuser 2 and is expanded and shaped into a parallel light flux having a predetermined cross-sectional shape, and then enters the first right-angle prism 33.

The parallel light fluxes deflected in the vertical direction by the first rectangular prism 33 serving as a rear mirror are sequentially reflected by the second rectangular prism 34 to the fifth rectangular prism 37 serving as the rear mirror, and then pass through the opening of the upper substrate B to enter the sixth rectangular prism 38. As shown in fig. 9, the second to fifth rectangular prisms 37 are arranged so that the parallel light flux deflected in the vertical direction by the first rectangular prism 33 and directed to the sixth rectangular prism bypasses, for example, a pipe for supplying deionized water and a pipe 39 for ventilation.

The light beam deflected in the horizontal direction by the sixth rectangular prism 38 serving as a rear mirror is incident on the half mirror 40. The light beam reflected by the half mirror 40 is guided to the positional deviation inclination detection system 41. On the other hand, the light beam passing through the half mirror 40 is guided to the polarization state switching means 42 constituted by the 1/2 wavelength plate 10 and the depolarizer 20. In the misalignment/tilt detection system 41, the misalignment and tilt of the parallel light beam (incident on the diffractive optical element 4 serving as the light integrator) incident on the polarization state switching means 42 with respect to the optical axis AX are detected.

Here, when an ArF excimer laser light source is used as the laser light source 1, for example, fluorite is generally used as a light transmitting member to be irradiated with high energy density light to ensure a desired durability. In this case, as described later, the polarization plane of the linear polarization changes between a short-term state and a long-term state when passing through the light transmitting member formed of fluorite. When the linearly polarized polarization plane is changed by the light transmitting member made of fluorite, the crystal prism 20a may lose its function as a non-polarizing element.

Fig. 10 is an explanatory view of crystal orientation of fluorite. Referring to FIG. 10, the crystal orientation of fluorite is based on the crystal axis a of the cubic system₁a₂a₃As defined. I.e. along the crystallographic axis + a₁Is defined as the crystal orientation [100]]Along the crystallographic axis + a₂Is defined as the crystal orientation [010]Along the crystallographic axis + a₃Is defined as the crystal orientation [001 ]]. In addition, a₁a₃The plane is defined as the crystal orientation [100]]And crystal orientation [001 ]]Crystal orientation at 45 degree orientation [101 ]]，a₁a₂The plane is defined as the crystal orientation [100]]And crystal orientation [010 ]]Crystal orientation at 45 degree [110]]，a₂a₃The plane being defined as the crystal orientation [010 ]]And crystal orientation [001 ]]Crystal orientation [011 ] at 45 degree]. Second, with the crystal axis + a₁Crystal axis + a₂And the crystal axis + a₃The direction of equal acute angles is defined as the crystallographic orientation [111]]. In FIG. 10, only the axis + a to be crystallized₁Crystal axis + a₂And the crystal axis + a₃The crystallographic orientation of the defined enclosed space is plotted, but the same crystallographic orientation can be defined in other spaces as well.

According to the verification of the present inventors, in the light transmitting member formed of fluorite, if the traveling direction of light coincides with the crystal orientation [111] or the crystal orientation equivalent to the crystal structure thereof, the plane of polarization of linear polarization substantially does not change through the light transmitting member. Similarly, if the direction of light propagation coincides with the crystal orientation [100] or a crystal orientation equivalent to the crystal structure of the orientation, the plane of polarization of the linear polarization substantially does not change when the light-transmitting member made of fluorite is transmitted therethrough. On the other hand, if the traveling direction of light coincides with the crystal orientation [110] or a crystal orientation equivalent to the crystal structure of the orientation, the polarization plane of linear polarization changes between short-term and long-term states by passing through the light transmitting member made of fluorite.

In the present specification, the phrase "crystal orientation equivalent to a certain crystal orientation in a crystal structure" refers to a crystal orientation in which the order of indices of the crystal orientation is replaced with respect to a certain crystal orientation, and a crystal orientation in which at least a part of each index is reversed in sign. For example, in the case where the crystal orientation is [ uvw ], [ uwv ], [ vuw ] [ vwu ] [ wuv ] [ wvu ], [ -uvw ], [ -uwv ], [ -vuw ], [ -vwu ], [ -wuv ], [ -wvu ], [ u-vw ], [ u-wv ], [ v-uw ], [ v-wu ], [ w-uv ], [ w-vu ], [ uv-w ], [ uv-v ], [ vu-w ], [ vw-v ], [ wv-u ], [ -u-vw ], [ -u-wv ], [ wu-v ], [ wv-u ], [ -u-vw ], [ -u-v ], [ -u-w ], [ -u-v ], [ -u-w ], [ uv-w ], [ -u-v-w ], [ uv, [ -v-wu ], [ -vu-w ], [ -vw-u ], [ -w-uv ], [ -w-vu ], [ -wu-v ], [ -wv-u ], [ u-v-w ], [ u-w-v ], [ v-u-w ], [ v-w-u ], [ w-u-v ], [ w-v-u ], [ -u-v-w ], [ -u-w-v ], [ -v-u-w ], [ -v-w-u ], [ -w-u-v ], [ -w-v-u ] and the like are crystal orientations equivalent in crystal structure. The crystal orientation [ uvw ] and the equivalent crystal orientation in terms of crystal structure are expressed by the crystal orientation < uvw >. In addition, a plane perpendicular to the crystal orientation [ uvw ] and equivalent crystal orientation thereto in the crystal structure, that is, a crystal plane (uvw) and equivalent crystal plane thereto in the crystal structure are represented by { uvw }.

In the present embodiment, the light transmitting member made of fluorite and disposed in the optical path between the laser light source 1 and the polarization switching means 42 has a crystal orientation <111> or a crystal orientation <100> that is closer to the crystal orientation <110 >. Specifically, when the optical member fixedly positioned in the optical path is formed of fluorite so as to constitute the lens components (2a, 2b) of the optical diffuser 2, the optical axis of the optical member is set to substantially coincide with the crystal orientation <111> or the crystal orientation <100 >.

In this case, since the laser light substantially passes along the crystal orientation <111> or the crystal orientation <100>, the plane of polarization of the linear polarization passing through the lens components (2a, 2b) is substantially unchanged. Similarly, when the off-angle prism pair 31 is also formed of fluorite, the optical axis thereof is set to substantially coincide with the crystal orientation <111> or the crystal orientation <100>, whereby a change in the polarization plane of the passing linear polarization can be substantially avoided.

In addition, when the right-angle prisms 33 to 38 as the back surface mirrors are formed of fluorite, the incident surfaces and the exit surfaces of the right-angle prisms 33 to 38 are set to substantially coincide with the crystal plane {100}, and the reflection surfaces of the right-angle prisms 33 to 38 are set to substantially coincide with the crystal plane {110 }. In this case, since the laser light substantially passes along the crystal orientation <100>, the polarization plane of the linear polarization passing through the right-angle prisms 33 to 38 is substantially unchanged.

In addition, when the parallel plate 32 as the light beam parallel movement means provided to be tiltable in the optical path relative to the optical axis AX so as to move the light incident along the optical axis AX in parallel is formed of fluorite, the optical axis of the parallel plate 32 is set to substantially coincide with the crystal orientation <100 >. This is about 35 degrees relative to the crystal orientation <111> and <110>, and the crystal orientation <100> and <110> are 45 degrees.

When the optical axis of the parallel plate 32 is made to substantially coincide with the crystal orientation <111>, that is, when the optical plane thereof is made to substantially coincide with the crystal plane {111}, the parallel plate 32 is inclined at a maximum (for example, 30 degrees) with respect to the optical axis AX, the traveling direction of the laser beam passing through the inside thereof becomes in the vicinity of the crystal orientation <110 >. Therefore, when the optical axis of the parallel plate 32 is substantially aligned with the crystal orientation <100>, that is, when the optical surface thereof is substantially aligned with the crystal plane {100}, the traveling direction of the laser beam passing through the inside thereof can be kept separated from the crystal orientation <110> to some extent. Therefore, by making the optical axis of the parallel plate 32 substantially coincide with the crystal orientation <100>, it is possible to prevent the polarization plane of the linear polarization passing through the parallel plate 32 from being changed regardless of the posture thereof.

In the above description, since the change of the polarization plane of the linear polarization passing through the light transmitting member disposed in the optical path between the laser light source 1 and the polarization switching means 42 is avoided, the light traveling direction is set to be closer to the crystal orientation <111> or <100> than the crystal orientation <110 >. However, the present invention is not limited to this, and the light transmitting member disposed in the optical path between the polarization switching means 42 and the mask M (and hence the wafer W) on the surface to be irradiated may be similarly set so as to avoid the change of the polarization plane of the linear polarization due to fluorite across the entire illumination optical path.

In the above description, since the change of the polarization plane of the linear polarization passing through the light transmitting member formed of fluorite is avoided, the traveling direction of the light is set to be closer to the crystal orientation <111> or the crystal orientation <100> than the crystal orientation <110 >. However, the present invention is not limited to fluorite, and for example, by setting the light transmitting member to be made of a cubic crystal material such as calcium fluoride, barium fluoride, or magnesium fluoride in the same manner, it is possible to prevent the change of the polarization plane of linear polarization caused by the crystal material.

Here, as shown in fig. 9, a plurality of (6 in the example shown in fig. 9) rectangular prisms 33 to 38 are arranged in the beam matching unit BMU. In general, in the case where the laser light source 1 is a KrF excimer laser light source or an ArF excimer laser light source, and the linearly polarized light is incident on a right-angle prism as a back mirror, if the incident linearly polarized polarization plane does not coincide with the P-polarization plane or the S-polarization plane (the incident polarization plane is neither P-polarization nor S-polarization with respect to the reflection plane), the linear polarization is converted into elliptical polarization by total reflection at the right-angle prism. The polarization state switching means 42 in this embodiment is based on the premise of linear polarization incidence, and the elliptical polarization incidence cannot achieve the desired effect.

In the present embodiment, as shown in fig. 11, as the second phase member for converting incident elliptically polarized light into linearly polarized light, it is preferable that, for example, an 1/4 wavelength plate 11 whose crystal optical axis is rotatable about the optical axis AX is provided on the light source side (left side in the drawing) of the 1/2 wavelength plate 10 in the polarization state switching means 42. In this case, even if the elliptical polarization is incident on the polarization state switching means 42 due to, for example, a rectangular prism, the crystal optical axis of the 1/2 wavelength plate 11 is set in accordance with the characteristics of the incident elliptical polarization, so that the linear polarization is incident on the 1/2 wavelength plate, and the original operation of the polarization state switching means 42 can be maintained. In fig. 11, although the 1/4 wavelength plate is disposed on the light source side of the 1/2 wavelength plate 10, the 1/4 wavelength plate 11 may be disposed on the light shield side (right side in the drawing) of the 1/2 wavelength plate 10.

In the above description, the method of avoiding the change of the polarization plane of the linear polarization passing through the light transmitting member formed of fluorite and the method of maintaining the original operation of the polarization state switching means even if the incident of the elliptical polarization is caused by the rectangular prism can be applied to the embodiments of fig. 1 to 4. However, this method is not limited thereto, and this method may be applied to the modified examples of fig. 5 to 8.

In the above description, the crystal orientation of the crystal material is set in order to avoid a change in the plane of polarization (change in the polarization state) of the linearly polarized light passing through the light transmitting member formed of a cubic system such as fluorite. Instead of or in combination with the above-described method, a light-transmitting member formed of a cubic crystal material can be dynamically held by a method disclosed in, for example, U.S. patent publication No. US2002/0163741A (or WO 02/16993). Thus, when light having a high energy density passes through the light transmitting member formed of a cubic system such as fluorite, even if the light transmitting member expands or contracts due to heat, occurrence of stress birefringence in the light transmitting member can be suppressed, and a change in the plane of polarization (change in the polarization state) of linear polarization passing through the light transmitting member can be suppressed.

Next, an example of improving the imaging performance (depth of focus, resolution, and the like) of the projection optical system and enabling good and faithful transfer will be described, specifically, by using what kind of mask pattern and what kind of polarization state of light are used to illuminate the mask. First, for example, in the case of dipole illumination (illumination system in which two high-light-intensity partial regions are formed at or near the pupil plane with a space therebetween in general), as shown in fig. 14, the mask is illuminated with light in a linearly polarized state having a polarization plane (indicated by a bidirectional arrow F1 on the figure) in a direction (y direction: Z direction on the corresponding pupil plane) perpendicular to a direction (X direction: X direction on the corresponding pupil plane) in which a line formed on the mask and a space pattern (line and space) 141 are spaced apart from each other along a pitch direction (X direction: X direction on the corresponding mask) by two surface light sources 142a and 142b formed at a space therebetween, and the mask pattern 141 can be enhanced in imaging capability of the projection optical system. That is, in the case of a two-dimensional pattern in which a vertical pattern and a horizontal pattern are mixed, for example, when a photomask is illuminated with unpolarized light, a pattern transfer can be performed with high yield without line width abnormality between the vertical pattern and the horizontal pattern.

In particular, in the above-described dipole illumination, in order to improve the imaging performance of the projection optical system, the two surface light sources 142a and 142b are formed symmetrically to the optical axis AX, and it is desirable that the following conditional expression (1) is satisfied.

0.7≤σo/φp (1)

In conditional expression (1), σ o is a value defined as φ o/φ p (generically referred to as outer σ). Here, as shown in fig. 14, Φ o is the diameter of a circumscribed circle with the optical axis AX as the center and the two surface light sources 142a and 142b, and Φ p is the diameter of the pupil plane 143. Further, in order to achieve further improvement in the imaging ability of the projection optical system, the lower limit value of the conditional expression (1) is preferably set to 0.9.

In the above-described dipole illumination, in order to improve the imaging performance of the projection optical system, it is desirable that the two surface light sources 142a and 142b are formed symmetrically to the optical axis AX and satisfy the following conditional expression (2).

0.5≤σi/σo (2)

In conditional expression (1), σ i is a value defined as φ i/φ p (generically referred to as inner σ). σ o is the outer σ defined as φ o/φ p above. Here, as shown in fig. 14, Φ i is a diameter of an inscribed circle of the two surface light sources 142a and 142b with the optical axis AX as a center, and Φ p is a diameter of the pupil surface 143. Further, in order to achieve further improvement in the imaging capability of the projection optical system, the lower limit value of the conditional expression (2) is preferably set to 0.67 (about 2/3).

Next, for example, in the case of circular illumination (generally, an illumination system in which one high-light-intensity partial region substantially centered on the optical axis is formed on or near the pupil plane), the mask pattern 151 can be illuminated with light in a linearly polarized state having a polarization plane (indicated by a double-headed arrow F2 on the figure) in a direction (y direction: Z direction on the corresponding pupil plane) perpendicular to the pitch direction (X direction: X direction on the corresponding mask) between the line and space pattern (line and space pattern)151 using a phase shift mask as a mask, as shown in fig. 15, thereby improving the imaging capability of the projection optical system with respect to the mask pattern 151. That is, in the case of circular illumination as well as in the case of dipole illumination, when a photomask is illuminated with unpolarized light for example, for a two-dimensional pattern in which a longitudinal pattern and a lateral pattern are mixed, a pattern transfer can be performed with high yield without line width abnormality between the longitudinal pattern and the lateral pattern.

In particular, in the circular illumination, it is desirable that the following conditional expression (3) is satisfied in order to sufficiently improve the imaging performance of the projection optical system.

σ≤0.4 (3)

In conditional expression (3), σ is a value defined as φ/φ p (generally referred to as σ value). As shown in fig. 15, Φ is the diameter of the circular surface light source 152 (generally, the size of a region of high light intensity distribution), and Φ p is the diameter of the pupil surface 153. In order to further improve the imaging performance of the projection optical system, it is desirable that the upper limit of the conditional expression (3) be set to 0.3.

Next, conditions to be satisfied by light in a substantially linear polarization state or a substantially unpolarized state in the present invention will be described. First, in the present invention, it is considered that the S1 component of the Stokes' parameter of the substantially linearly polarized light preferably satisfies the following conditional expression (4).

0.6≤|S1| (4)

In the present invention, it is considered that the S1 and S2 components of the Stokes' parameter of the substantially unpolarized light preferably satisfy the following conditional expressions (5) and (6).

|S1|≤0.1 (5)

|S2|≤0.1 (6)

Since light in a substantially linearly polarized state is more linearly polarized, the lower limit value of conditional expression (4) is preferably set to 0.8. For example, when the light source is an ArF excimer laser that supplies light having a wavelength of 193nm, and the numerical aperture on the imaging side of the projection optical system PL is 0.92, a 6% half-tone cross mark (mask error 2 ± nm) of a 65nm line-and-space pattern is used, and σ o is set to 0.93 and σ i is set to 0.73 (that is, σ of each surface light source is set to 0.2) in the dipole illumination shown in fig. 14, if the exposure error is 2% and the line width error is ± 10%, the depth of focus DOF (166nm) in the non-polarized state can be increased to the depth of focus DOF (202nm) in the longitudinal pattern. In addition, when the condition (4), i.e., the polarization degree exceeds 0.8, the line width variation caused by the polarization degree variation is substantially negligible. Under the above conditions, the line width difference between the degree of polarization of 0.8(| S1| ═ 0.8) and the degree of polarization of 1.0(| S1| - > 1.0) yields only 0.2 nm. This difference is essentially negligible. That is, with respect to the value of conditional expression (4), an expression in the range of 0.8 to 1.0 does not matter.

When the substantially unpolarized light is closer to unpolarized light, the upper limit of the conditional expression (5) and the upper limit of the conditional expression (6) are preferably both set to 0.04. Here, in the case where conditional expressions (5) and (6), that is, the value of the degree of polarization, is less than 0.1, the line width difference due to the polarization can be suppressed within 2nm (the light source wavelength is 193nm, the imaging-side numerical aperture of the projection optical system PL is 0.78, a phase shift mask of an independent pattern of 50nm is used, and the σ value in the circular illumination shown in fig. 15 is set to 0.2 (small σ illumination)). Then, in the case where the conditional expressions (5) and (6), that is, the value of the degree of polarization is less than 0.04, the line width difference due to the polarization under the above conditions can be suppressed within 0.7 nm. In the conditional expressions (5) and (6), when the region in the surface light source is microscopically viewed, even if the degree of polarization is high, the region can be substantially regarded as non-polarized if the polarization state has a very fine periodic change, and therefore, a moving average of a large region having a σ value of 0.1 can be used for calculating the distribution of the degree of polarization in the surface light source.

Therefore, for example, in circular illumination, wheel band illumination, or the like, if a desired unpolarized state with a sufficiently low residual polarization degree cannot be realized, a difference in line width of the pattern occurs between the longitudinal direction and the lateral direction. Further, in the case where a desired linear polarization state having a polarization plane in a predetermined direction cannot be realized in, for example, dipole illumination or the like, the imaging performance for a fine pattern having a line width of a specific pitch cannot be improved. In a variation of the present embodiment, a polarization monitor is provided to detect the polarization state of light for illuminating the mask M (or the wafer W) as the illuminated surface.

Fig. 16 is a schematic configuration diagram of the exposure apparatus of fig. 1 with a polarization monitor for detecting the polarization state of the illumination light. In the exposure apparatus according to the modified example of fig. 16, the structure between the microlens array 8 and the mask M is different from that of the exposure apparatus of fig. 1. In other words, in the modified example, the light beams emitted from the secondary light sources (generally, a predetermined light intensity distribution formed on or near the pupil plane of the optical illumination device) formed on the back focal plane of the microlens array 8 pass through the beam splitter 51 and the focusing optical system 9a, and then the mask baffle MB is illuminated in a superimposed manner.

In this way, a rectangular field corresponding to the shape and focal length of each microlens constituting the microlens array 8 is formed on the mask blank MB as an illumination field stop. The internal structure and operation of the polarization monitor 50 incorporating the beam splitter 51 will be described later. The light flux passing through the rectangular opening (light transmitting portion) of the mask blank MB is focused by the imaging optical system 9b, and then superimposed on the mask M on which a predetermined pattern is formed. In this way, the imaging optical system 9b forms an image of the rectangular opening of the mask blank MB on the mask M.

In the exposure apparatus according to the modified example of fig. 16, the structure between the deflecting mirror 3 and the diffractive optical element 4 is different from that of the exposure apparatus of fig. 1. That is, in the modified example, the polarization state switching means (1/4 wavelength plate 11, 1/2 wavelength plate 10, and depolarizer 20) having the structure shown in fig. 11 is disposed instead of the polarization state switching means (1/2 wavelength plate 10 and depolarizer 20) of fig. 1. As will be described later, the output of the polarization monitor 50 is supplied to the control section 70. Further, the control section 70 drives the polarization switching means (11, 10, 20) via the drive system 71. In the polarization state switching means having the structure shown in fig. 11, the 1/2 wavelength plates 10 may be replaced by a plurality of 1/4 wavelength plates.

Fig. 17 is a perspective view schematically illustrating an internal configuration of the polarization monitor of fig. 16. Referring to fig. 17, the polarization monitor 50 includes a first beam splitter 51 disposed in the optical path between the microlens array 8 and the focusing optical system 9 a. The first beam splitter 51 has a non-coated parallel plate (i.e., white glass) shape made of, for example, quartz glass, and has a function of extracting a polarization state reflected light different from a polarization state of an incident light from an optical path.

The light extracted from the first beam splitter 51 is incident on the second beam splitter 52. The second beam splitter 52 has an uncoated parallel plate shape made of, for example, quartz glass, similarly to the first beam splitter 51, and has a function of generating reflected light in a polarization state different from that of incident light. Then, the P polarization to the first beam splitter 51 becomes the S polarization to the second beam splitter 52, and the S polarization to the first beam splitter 51 becomes the P polarization to the second beam splitter 52.

The light passing through the second beam splitter 52 is detected by the first light intensity detector 53, and the light reflected by the second beam splitter 52 is detected by the second light intensity detector 54. The outputs of the first light intensity detector 53 and the second light intensity detector 54 are transmitted to the control system 70, respectively. In addition, the 1/4 wavelength plates 11, 1/2 wavelength plate 10 and the depolarizer 20 constituting the polarization state switching means are driven as required by the driving system 71.

As described above, in the first beam splitter 51 and the second beam splitter 52, the reflectance for P polarization and the reflectance for S polarization are substantially different. Therefore, in the polarization monitor 50, the reflected light from the first beam splitter 51 includes, for example, about 10% of the S-polarization component (S-polarization component for the first beam splitter 51 and P-polarization component for the second beam splitter 52) of the incident light from the first beam splitter 51, and, for example, about 1% of the P-polarization component (P-polarization component for the first beam splitter 51 and S-polarization component for the second beam splitter 52) of the incident light from the first beam splitter 51.

The reflected light from the second beam splitter 52 includes, for example, a P-polarization component (P-polarization component for the first beam splitter 51 and S-polarization component for the second beam splitter 52) of about 0.1% of the incident light from the first beam splitter 51, and an S-polarization component (S-polarization component for the first beam splitter 51 and P-polarization component for the second beam splitter 52) of about 0.1% of the incident light from the first beam splitter 51.

Thus, in the polarization monitor 50, the first beam splitter 51 has a function of extracting the reflected light with a polarization state different from the polarization state of the incident light from the optical path according to the reflection characteristic thereof. As a result, the polarization variation of the polarization characteristic of the second beam splitter 52 has only a little influence, but the polarization state (degree of polarization) of the incident light to the first beam splitter 51 and hence the polarization state of the illumination light to the mask M can be detected based on the output of the first light intensity detector 53 (information on the intensity of the transmitted light of the second beam splitter 52, that is, information on the intensity of light having approximately the same polarization state as the reflected light of the first beam splitter 51).

In addition, the polarization monitor 50 is set such that P polarization for the first beam splitter 51 becomes S polarization for the second beam splitter 52, and S polarization for the first beam splitter 51 becomes P polarization for the second beam splitter 52. As a result, the amount (intensity) of the incident light to the first beam splitter 51 and the amount of the illumination light to the mask M can be detected based on the output of the second light intensity detector 54 (information on the intensity of the light sequentially reflected by the first beam splitter 51 and the second beam splitter 52) substantially all over the influence of the change in the polarization state of the incident light to the first beam splitter 51.

Thus, the polarization monitor 50 can detect the polarization state of the incident light from the first beam splitter 51, and can determine whether the illumination light to the mask M is in a desired non-polarized state or a linearly polarized state. Then, when the control system 70 confirms whether the illumination light to the mask M (or the wafer W) is in the desired non-polarized state or the linearly polarized state based on the detection result of the polarization monitor 50, the 1/4 wavelength plates 11 and 1/2 wavelength plate 10 and the depolarizer 20 constituting the polarization state switching means are driven and adjusted by the driving system 71, so that the illumination light to the mask M can be adjusted to the desired non-polarized state or the linearly polarized state.

As described above, the polarization monitor 50, the control system 70, the drive system 71, and the polarization state switching means (11, 10, 20) having a function of adjusting the polarization state of the irradiated surface are disposed in the optical path between the light source 1 and the mask M, and constitute polarization state variation correction means for correcting the variation in the polarization state on the surface of the mask M. In this case, an optical member formed of an optical member having a characteristic of changing the polarization state of incident light and emitting the light, for example, a crystalline optical material such as fluorite having a birefringent characteristic or crystal having an optical rotation characteristic, is not disposed as much as possible in the optical path between the polarization monitor 50 and the mask M. It is desirable that an optical member having a characteristic of emitting incident light with its polarization state changed is not disposed as much as possible in the optical path between the polarization monitor 50 and the light source 1. However, in order to ensure durability against light irradiation, when optical components such as the diffractive optical element 4 and 6 are formed of fluorite or crystal, for example, the influence of polarization variation caused by these optical components needs to be taken into consideration.

In the above description, if the reflected light from the first optical splitter 51 is directly incident on the first light intensity detector 53, the output of the first light intensity detector 53 is not affected by the polarization variation due to the polarization characteristic of the second optical splitter 52, and thus the polarization state of the incident light from the first optical splitter 51 can be detected with high accuracy. Further, the structure shown in fig. 17 is not limited, and the specific structure of the polarization monitor 50 may be variously changed. In the above description, the polarization state switching means is constituted by the 1/4 wavelength plates 11 and 1/2 wavelength plate 10 and the depolarizer 20, but the polarization state switching means may be constituted by the 1/2 wavelength plate 10 and the depolarizer 20. In this case, the control system 70 drives 1/2 the wavelength plate 10 and the depolarizer 20 as needed via the drive system 71.

In the above description, it is preferable that the reflectance of the first beam splitter 51 and the reflectance of the second beam splitter 52 for P polarization and the reflectance for S polarization have reflection characteristics sufficiently different from each other in terms of detecting the polarization state of the incident light of the first beam splitter with high accuracy. Specifically, the intensity ratio Ip/Is of the P-polarized intensity Ip to the S-polarized intensity Is included in the reflected light of the first beam splitter 51 Is preferably a reflection characteristic satisfying the condition Ip/Is < 1/2 or Ip/Is > 2.

In addition, in the above description, a beam splitter having a parallel panel shape is used, and its reflected light is extracted from the optical path. However, it is not limited thereto. The light splitter is used for capturing the penetrating light with the polarization state different from the polarization state of the incident light from the light path, and the polarization state of the incident light entering the light splitter can be detected by the light splitter according to the intensity of the penetrating light extracted from the light path. In this case, it Is preferable that the intensity ratio Ip/Is of the P-polarized intensity Ip to the S-polarized intensity Is included in the reflected light from the spectroscope satisfies the reflection characteristic of the condition that Ip/Is < 1/2 or Ip/Is > 2.

Therefore, as described above, if the linear polarization emitted from the laser light source 1 is changed to elliptical polarization by the influence of the total reflection of the rectangular prism, it is considered that the linear polarization enters the polarization state switching means (11, 10, 20). Further, if the linear polarization emitted from the laser light source 1 becomes elliptical polarization under the influence of an optical member having a property of changing the polarization state of incident light, such as an optical member formed of fluorite, for example, it is considered that the linear polarization enters the polarization state switching means (11, 10, 20).

In this case, the 1/4 wavelength plate 11 converts incident elliptically polarized light into linearly polarized light, and the crystal optical axis must be set at a desired angular position in accordance with the major axis direction of the incident elliptically polarized light. The 1/2 wavelength plate 10 converts incident linearly polarized light into linearly polarized light having a plane of polarization in a predetermined direction, and the crystal optical axis thereof must be set at a desired angular position according to the direction of the plane of polarization of the incident linearly polarized light. Next, a method of adjusting the crystal optical axis of the 1/4 wavelength plate 11 and the crystal optical axis of the 1/2 wavelength plate 10 will be described by taking the polarization state switching means (11, 10, 20) of fig. 11 as an example. In an optical system including the 1/4 wavelength plates 11 and the 1/2 wavelength plate 10 configured such that the crystal optical axis can freely rotate around the optical axis, the following method is generally applicable.

FIG. 18 is a flowchart of a method for adjusting the crystal optical axis of the 1/4 wavelength plate and the crystal optical axis of the 1/2 wavelength plate in the polarization state switching means of FIG. 11. Referring to fig. 18, in the adjusting method of the present embodiment, the depolarizer 20 is retracted from the optical path, and the crystalline optical axis of the 1/4 wavelength plate 11 is at an angular position where the respective initial setting criteria are, for example, at an angular position of-45 degrees (S11). Then, in a state where the crystal optical axis of the 1/4 wavelength plate 11 is fixed at the-45 ° standard angle position, the 1/2 wavelength plate 10 is rotated from the-45 ° standard angle position to the +45 ° angle position (for example, every +5 degrees), and the polarization monitor 50 output of the 1/2 wavelength plate 10 at each angle position is extracted (S12).

FIG. 19 is a graph showing the change in output of a polarization monitor at various angular positions for the crystallographic optical axis of the 1/2 wavelength plate when the crystallographic optical axis of the 1/4 wavelength plate is fixed at the-45 degree standard angular position. In fig. 19, the horizontal axis represents the angular position (degrees) of the crystal optical axis of the 1/2 wavelength plate 10, and the vertical axis represents the output of the polarization monitor 50 (the value of the stecke parameter S1 component). Next, the crystal optical axis of the 1/4 wavelength plate 11 is rotated from the standard angular position of-45 degrees to the angular position of +45 degrees, for example, every +15 degrees, and at each angular position, the crystal optical axis of the 1/2 wavelength plate 10 is rotated from the standard angular position of-45 degrees to the angular position of +45 degrees, for example, every +5 degrees, and the polarization monitor 50 output of the 1/2 wavelength plate 10 at each angular position is extracted (S13).

FIG. 20 is a graph showing the change in output of a polarization monitor at various angular positions for the crystal optical axis of the 1/2 wavelength plate when the crystal optical axis of the 1/4 wavelength plate is set at various angular positions. In fig. 20, a indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of-45 degrees, b indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of-30 degrees, c indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of-15 degrees, d indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of 0 degrees, e indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of +15 degrees, f indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of +30 degrees, and g indicates a state where the crystal optical axis of the 1/4 wavelength plate 11 is at the standard angle position of +45 degrees. In addition, as in fig. 19, the horizontal axis represents the angular position (degree) of the crystal optical axis of the 1/2 wavelength plate 10, and the vertical axis represents the output of the polarization monitor 50.

FIG. 21 is a graph showing the output versus change of a polarization monitor for various angular positions of the crystallographic optical axis of the 1/4 wavelength plate. In fig. 21, the horizontal axis represents the angular position (degree) of the crystal optical axis of the 1/4 wavelength plate 11, and the vertical axis represents the output contrast of the polarization monitor 50 (the contrast of the change in the stackers parameter S1 component). Here, for example, the output contrast at each angular position of the crystal optical axis of the 1/4 wavelength plate 11 is defined by using the maximum value and the minimum value of each output variation curve a to g in fig. 20, and by using the contrast (maximum value-minimum value)/(maximum value + minimum value).

In fig. 21, when the crystal optical axis of the 1/4 wavelength plate is set to have the maximum output contrast, the elliptically polarized light incident on the 1/4 wavelength plate 11 is converted into linearly polarized light. In the adjustment method of this example, the angular position of the crystal optical axis of the 1/4 wavelength plate 11 (approximately +30 degrees in fig. 21) at which the output contrast becomes maximum is determined by referring to the output contrast change of the polarization monitor in each angular position state of the crystal optical axis of the 1/4 wavelength plate 11, and elliptically polarized light is converted into linearly polarized light as a desired first angular position (S14).

FIG. 22 is a graph showing the change in output of a polarization monitor at various angular positions of the crystal optical axis of the 1/2 wavelength plate when the crystal optical axis of the 1/4 wavelength plate is fixed at a first angular position at which elliptically polarized light is converted to linearly polarized light. In fig. 22, the horizontal axis represents the angular position (degree) of the crystal optical axis of the 1/2 wavelength plate 10, and the vertical axis represents the output of the polarization monitor 50. In fig. 22, when the crystal optical axis of the 1/2 wavelength plate 10 is set to maximize or minimize the output of the polarization monitor 50, the linearly polarized light incident on the 1/2 wavelength plate 10 is converted into V polarization (longitudinal polarization) or H polarization (transverse polarization).

In the adjustment method of the present embodiment, when the crystal optical axis of the 1/4 wavelength plate 11 is fixed at the first angular position, the angular position of the crystal optical axis of the 1/2 wavelength plate 10 (in fig. 22, the angular position of about-17.5 degrees or +27.5 degrees or its vicinity) at which the output is the maximum or minimum is determined with reference to the change in the output of the polarization monitor 50 at each angular position of the crystal optical axis of the 1/2 wavelength plate 10, and the incident linear polarization is converted into the V polarization or the H polarization as the desired second angular position (S15).

As such, finally, the control system 70 positions the angular position of the crystal optical axis of the 1/4 wavelength plate 11 at a first angular position where the incident elliptically polarized light is converted into linearly polarized light and positions the angular position of the crystal optical axis of the 1/2 wavelength plate 10 at a second angular position where the incident linearly polarized light is converted into linearly polarized light having a plane of polarization (e.g., V-polarization or H-polarization) in a specific direction via the drive system 71 (S16). In addition, since the first angular position and the second angular position are considered in response to a change in the illumination condition (a change in the shape or size of the light intensity distribution formed on the pupil plane of the optical illumination device or in the vicinity thereof), it is preferable to set and correct the crystal optical axis of the 1/4 wavelength plate 11 and the crystal optical axis of the 1/2 wavelength plate 10 as needed. In the above embodiment, the 1/4 wavelength plate and the 1/2 wavelength plate were used as the polarization state switching means, but the 2-plate 1/4 wavelength plate may be used as the polarization state switching means.

The above description is based on fig. 1 or 16, and the illumination pupil distribution forming means for forming a predetermined light intensity distribution on the pupil surface or its vicinity based on the light beam emitted from the light source is an optical illumination device including two diffractive optical elements (4, 6), and the exposure device is provided with the optical illumination device. But is not limited to the architecture of fig. 1 or 16. The optical lighting device to which the present invention is applicable may be variously modified. Fig. 23 is a schematic structural view showing an exposure apparatus having an illumination pupil distribution forming means of a different configuration from that of fig. 1 or 16.

The exposure apparatus of the modification in fig. 23 has a similar structure to that of the exposure apparatus of fig. 16, but the structure of the illumination pupil distribution forming means, that is, the structure between the diffractive optical element 4 and the microlens array 8 is different. Next, the structure and operation of the modification of fig. 23 will be described with emphasis on differences from the exposure apparatus of fig. 16. In the exposure apparatus according to the modified example of fig. 23, for example, the light beam passing through the belt illumination diffractive optical element 4a enters the afocal lens (relay optical system) 85. The afocal optical system 85 is set to an afocal system (afocal optical system) such that the front focal position is substantially the same as the position of the diffractive optical element 4a, and the back focal position substantially coincides with the position of a predetermined plane 86 shown by a broken line in the drawing.

Therefore, the substantially parallel light flux entering the diffractive optical element 4a forms an annular light intensity distribution on the pupil surface of the telephoto lens 85, and then becomes a substantially parallel light flux and is emitted from the telephoto lens. Further, in the optical path between the front lens group 85a and the rear lens group 85b of the telephoto lens 85, a cone axicon (cone axicon)87, a first cylindrical lens pair 88, and a second cylindrical lens pair 89 are arranged in this order from the light source side at the pupil or its vicinity, but their detailed configuration and operation will be described later. For the sake of simplicity, the basic configuration and operation will be described with the operation of the axicon prism 87, the first cylindrical lens pair 88, and the second cylindrical lens pair 89 omitted.

The light flux passing through the afocal lens 85 is incident on the microlens array 8 as an optical integrator through a zoom lens (magnification changing optical system) 90 whose σ value is variable. The predetermined surface 86 is positioned near the front focal position of the zoom lens 90, and the incidence surface of the microlens array 8 is positioned near the rear focal position of the zoom lens 90. In other words, the zoom lens 90 is disposed such that the predetermined surface 86 and the incident surface of the microlens array 8 are substantially in a fourier transform relationship, and the pupil surface of the telephoto lens 85 and the incident surface of the microlens array 8 are disposed so as to be optically conjugate. Therefore, a zonal illumination field centered on the optical axis, for example, is formed on the entrance surface of the microlens array 8 as well as on the pupil surface of the afocal lens 85. The overall shape of the field of view of the wheel is related to the focal length of the zoom lens 90 and varies similarly.

Each microlens constituting the microlens array 8 has a rectangular cross section similar to the shape of the field to be formed on the mask M (or the shape of the exposure region to be formed on the wafer W). The light flux incident on the microlens array 8 is divided two-dimensionally by a plurality of microlenses, and two light sources having approximately the same light intensity distribution as the field of illumination formed by the incident light on the microlens array 8, that is, secondary light sources configured to form a substantially annular band-shaped surface light source with the optical axis AX as the center, are formed on the back focal plane (or illumination pupil) thereof.

Fig. 24 is a schematic diagram showing the structure of the axicon prism optical system arranged in the optical path between the front lens group and the rear lens group of the telephoto lens in fig. 23. The axicon prism optical system 87 includes, in order from the light source side: a first prism member 87a having a light source side facing a plane and a mask side facing a concave conical refraction surface; and a second prism member 87b having a refracting surface facing the flat surface on the mask side and the convex cone shape on the light source side.

The concave conical refractive surface of the first prism member 87a and the convex conical refractive surface of the second prism member 87b are formed to complementarily contact each other. In addition, at least one of the first prism member 87a and the second prism member 87b is configured to be movable along the optical axis AX. The interval between the concave conical refraction surface of the first prism member 87a and the convex conical refraction surface of the second prism member 87b is variable.

In a state where the concave conical refraction surface of the first prism member 87a and the convex conical refraction surface of the second prism member 87b are in contact with each other, the axicon prism optical system 87 functions as a parallel plate and does not affect the formed annular secondary light source. However, when the concave conical refraction surface of the first prism member 87a and the convex conical refraction surface of the second prism member 87b are separated from each other, the axicon prism optical system 87 functions as a so-called optical diffuser. Therefore, as the interval of the circular cone axicon prism optical system 87 changes, the angle of the incident beam to the predetermined surface 86 changes.

FIG. 25 is an illustration of the cone axicon prism optics for the secondary light source formed by the wheel band illumination of the variation of FIG. 23. In the rim illumination of the modification of fig. 23, the minimum rim-shaped secondary light source 130a formed in a state where the interval between the axicon prism optical systems 87 is zero and the focal length of the zoom lens 90 is set to the minimum value is changed to a rim-shaped secondary light source 130b in which the outer diameter and the inner diameter are simultaneously enlarged without changing the width (1/2: the difference between the outer diameter and the inner diameter is indicated by an arrow) by enlarging the interval between the axicon prism optical systems 87 from zero to a predetermined value. In other words, the width of the annular secondary light source is not changed by the cone axicon prism optical system 87, but the annular ratio (inner diameter/outer diameter) and the size (outer diameter) are changed at the same time.

FIG. 26 is an illustration of the zoom lens acting as a secondary light source for the belt illumination of the variation of FIG. 23. In the belt illumination of the modification of fig. 23, the belt-shaped secondary light source 130a formed in the standard state is similarly enlarged to the belt-shaped secondary light source 130c in the entire shape by enlarging the focal length of the zoom lens 90 from the minimum value to a predetermined value. In other words, the belt ratio of the belt-shaped secondary light source does not change by the action of the zoom lens 90, and the width and size (outer diameter) thereof change simultaneously.

Fig. 27 is a schematic structural diagram showing a first cylindrical lens pair and a second cylindrical lens pair arranged in an optical path between a front lens group and a rear lens group of the telephoto lens in fig. 23. In fig. 27, a first cylindrical lens pair 88 and a second cylindrical lens pair 89 are arranged in this order from the light source side. The first cylindrical lens pair 88 includes, for example, in order from the light source side: a first cylindrical negative lens 88a having negative refractive power in the YZ plane and no refractive power in the XY plane; and a first cylindrical positive lens 88b having positive refractive power in the same YZ plane and no refractive power in the XY plane.

On the other hand, the second cylindrical lens pair 89 includes, in order from the light source side, for example: a second cylindrical negative lens 89a having negative refractive power in the XY plane and no refractive power in the YZ plane; and a second cylindrical positive lens 89b having positive refractive power in the same XY plane and no refractive power in the YZ plane. The first cylindrical negative lens 88a and the first cylindrical positive lens 88b are configured to rotate integrally around the optical axis AX. Similarly, the second cylindrical negative lens 89a and the first cylindrical positive lens 89b are configured to rotate integrally around the optical axis AX.

In this manner, in the state shown in fig. 27, the first cylindrical lens pair 88 functions as a beam expander having a magnification in the Z direction, and the second cylindrical lens pair 89 functions as a beam expander having a magnification in the X direction. In the modification of fig. 23, the magnification of the first cylindrical lens pair 88 and the magnification of the second cylindrical lens pair 89 are set to be the same as each other.

Fig. 28 to 30 are diagrams illustrating the operation of the first cylindrical lens pair and the second cylindrical lens pair for the secondary light source formed by the belt illumination of the variation of fig. 23. In fig. 28, the magnification direction of the first cylindrical lens pair 88 is set at an angle of +45 degrees about the optical axis AX with respect to the Z-axis, and the magnification direction of the second cylindrical lens pair 89 is set at an angle of-45 degrees about the optical axis AX with respect to the Z-axis.

Therefore, the magnification direction of the first cylindrical lens pair 88 and the magnification direction of the second cylindrical lens pair 89 are perpendicular to each other; in the synthetic optical system of the first cylindrical lens pair 88 and the second cylindrical lens pair 89, the magnification in the Z direction and the magnification in the X direction are the same as each other. As a result, in the perfect circular state shown in fig. 28, the light flux passing through the combining optical system of the first cylindrical lens pair 88 and the second cylindrical lens pair 89 is enlarged in the Z direction and in the X direction at the same magnification, and a perfect circular band-shaped secondary light source is formed at the illumination pupil.

In contrast, in fig. 29, the magnification direction of the first cylindrical lens pair 88 is set at an angle of +80 degrees about the optical axis AX with respect to the Z axis, and the magnification direction of the second cylindrical lens pair 89 is set at an angle of-80 degrees about the optical axis AX with respect to the Z axis. Therefore, in the synthetic optical system of the first cylindrical lens pair 88 and the second cylindrical lens pair 89, the magnification in the X direction is larger than the magnification in the Z direction. As a result, in the horizontal elliptical state of fig. 29, the light flux passing through the combining optical system of the first pair of cylindrical lenses 88 and the second pair of cylindrical lenses 89 is enlarged in the X direction at a larger magnification than in the Z direction, and a secondary light source in the form of a horizontally long belt elongated in the X direction is formed at the illumination pupil.

On the other hand, in fig. 30, the magnification direction of the first cylindrical lens pair 88 is set at an angle of +10 degrees around the optical axis AX with respect to the Z axis, and the magnification direction of the second cylindrical lens pair 89 is set at an angle of-10 degrees around the optical axis AX with respect to the Z axis. Therefore, in the synthetic optical system of the first cylindrical lens pair 88 and the second cylindrical lens pair 89, the magnification in the Z direction is larger than the magnification in the X direction. As a result, in the state of the vertical ellipse in fig. 30, the light flux passing through the combining optical system of the first pair of cylindrical lenses 88 and the second pair of cylindrical lenses 89 is enlarged in the Z direction at a larger magnification than in the X direction, and a secondary light source in the form of a long and long belt elongated in the Z direction is formed at the illumination pupil.

Next, by setting the first cylindrical lens pair 88 and the second cylindrical lens pair 89 in any state between the perfect circle state of fig. 28 and the transverse ellipse state of fig. 29, it is possible to form the transverse long wheel belt type secondary light source with various aspect ratios. In addition, by setting the first cylindrical lens pair 88 and the second cylindrical lens pair 89 in any state between the perfect circle state in fig. 28 and the longitudinal ellipse state in fig. 30, it is possible to form the elongated annular secondary light source having various aspect ratios. In the modification of fig. 23, circular illumination or various kinds of modified illumination can be performed by using a diffractive optical element for circular illumination, a diffractive optical element for multi-pole (quadrupole, etc.) illumination, or the like instead of the diffractive optical element 4a for annular illumination. As described above, the modification examples shown in fig. 23 to 30 can change the polarization state of the illumination light in accordance with the characteristics of the mask M, and further can adjust the aspect ratio of the secondary light source formed on the illumination pupil as needed. Thus, a good exposure can be performed using an appropriate illumination condition realized according to the pattern characteristics of the mask M.

In the above-described embodiments and modifications, when the polarization state of the surface to be irradiated (mask surface, wafer (photosensitive substrate) surface, and image plane) is changed to, for example, a linearly polarized state or a non-polarized state, or an X-polarized state and a Y-polarized state, if there is a variation in illuminance deviation on the surface to be irradiated, a variation in light intensity distribution on the pupil surface, or a variation in telecentric (telecentricity) characteristic on the surface to be irradiated, it is preferable to perform control of illuminance deviation, control of light intensity distribution on the pupil surface, and/or control of telecentric (telecentricity) characteristic on the surface to be irradiated, in accordance with the change in the polarization state of the surface to be irradiated, so as to suppress variation in illuminance deviation, variation in light intensity distribution on the pupil surface, and/or variation in telecentric (telecentricity) characteristic on the surface to be irradiated.

For example, the illuminance deviation on the incident surface can be controlled by changing the lens position and orientation of at least a part of the focusing optical system 9 of fig. 1, and the plurality of lens elements constituting the focusing optical system 9a of fig. 16 and 23. In addition, in the optical path between the focusing optical system 9 and the mask M in FIG. 1, for example, a density filter plate disclosed in JP-A-2002-100561 (and corresponding US2003/0025890A, and US2003/025890A is used as a reference in the present specification) or JP-A-2003-92253 (and corresponding US2003/067591A, and US2003/067591A is used as a reference in the present specification) is disposed in the optical path between the focusing optical system 9a and the mask stopper MB in FIGS. 16 and 23, and the illuminance deviation on the irradiated surface can be controlled by controlling the rotation angle and position of the density filter plate. Further, for example, the illumination deviation on the surface to be irradiated may be controlled by replacing the mask blank MB in fig. 16 and 23 with the variable edge disclosed in japanese laid-open patent publication No. 2002-.

Further, the light intensity distribution on the pupil plane can be controlled by disposing the concentration filter plate disclosed in the above-mentioned Japanese patent laid-open publication No. 2002-100561 (U.S. patent publication No. US2003/0025890A) or Japanese patent laid-open publication No. 2003-92253 (U.S. patent publication No. US2003/0067591A) in the vicinity of the illumination pupil, for example, in the vicinity of the exit side of the microlens array 8.

Then, the control of the telecentricity can be performed by changing the lens position and the posture of at least a part of the plurality of lens elements constituting the focusing optical system 9a of fig. 16 and 23, the focusing optical system 9 of fig. 1.

In the illuminance deviation arrangement on the irradiated surface, the light intensity distribution control on the pupil surface, and the telecentricity control, the relationship between the setting state of the polarization state switching means (the insertion and extraction of the depolarizer, the rotation angle of the 1/2 wavelength plate, and the rotation angle of the 1/4 wavelength plate), the illuminance deviation on the irradiated surface, the light intensity distribution on the pupil surface, and the telecentricity state is measured in advance, and the illuminance deviation on the irradiated surface, the light intensity distribution on the pupil surface, and the telecentricity state can be controlled according to the setting state of the polarization state switching means. Further, the illuminance deviation on the irradiated surface or the irradiated surface optically conjugate to the irradiated surface, the light intensity distribution on the pupil surface, and the telecentric state may be measured, and the illuminance deviation on the irradiated surface, the light intensity distribution on the pupil surface, and the telecentric state may be controlled based on the measurement result.

In the above embodiments and modifications, the microlens array 8 composed of a plurality of microlenses with positive refractive power arranged in a vertical row and densely is used as the optical integrator, but a cylindrical microlens array may be used instead. The cylindrical microlens array includes a first one-dimensional cylindrical lens array arranged at a pitch along a predetermined first direction; and a second one-dimensional cylindrical lens array arranged at a pitch along a second direction intersecting the first direction. The first and second one-dimensional cylindrical lens arrays of the cylindrical microlens array are preferably integrally provided on a light-transmissive substrate, and are provided with a plurality of cylindrical lens array plates including the first and second one-dimensional cylindrical lens arrays. The plurality of cylindrical lens array plates are preferably arranged at intervals along the optical axis direction. In addition, the pitch along the first direction of the first one-dimensional cylindrical lens array and the pitch along the second direction of the second one-dimensional cylindrical lens array are preferably at least one pitch of 2mm or less.

With this configuration, each refracting surface is different from a general fly-eye lens formed on a two-dimensional curved surface (spherical surface shape), and each refracting surface of the first and second one-dimensional cylindrical lens arrays of the cylindrical microlens array is formed on a one-dimensional curved surface (cylindrical shape), so that high precision processing becomes easy, and the manufacturing cost can be reduced. In particular, in the case where the minimum pitch of the cylindrical microlens array is 2mm or less, the effect of reducing the manufacturing cost is remarkable. That is, such a cylindrical microlens array can be manufactured by, for example, grinding, etching, and pressing.

Since the cylindrical microlens array having a low cost and high precision surface shape can be used to illuminate with excellent experimental uniformity, the imaging performance of polarized illumination is greatly improved, and a fine pattern with good transfer printing precision can be formed on the whole exposure region.

Such a cylindrical microlens array is disclosed in the specification and drawings of Japanese application laid-open No. 2002-152634 of the present applicant (and its corresponding application laid-open No. 445022 filed in U.S. 5/27/2003). In this specification, reference is made to the disclosure of this U.S. application No. 445022 for use.

In the exposure apparatus of the above embodiment, the mask (cross mark) is illuminated by the optical illumination device (illumination process), and the transfer pattern formed on the mask is transferred onto the photosensitive substrate by the projection optical system (exposure process), so that the microelectronic device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Next, an example of a method for obtaining a semiconductor device by forming a predetermined circuit pattern on a wafer or the like serving as a photosensitive substrate using the exposure apparatus of the above embodiment will be described with reference to a flowchart of fig. 12.

First, in step 301 of fig. 12, a metal film is evaporated on a batch of wafers. Next, in step 302, photoresist is coated on the metal film on the lot of wafers. Then, in step 303, the pattern image on the mask is sequentially exposed and transferred to each shot area on the batch of wafers through the projection optical system by using the exposure apparatus of the above embodiment. Thereafter, at step 304, the photoresist on the lot of wafers is developed, and then at step 305, etching is performed using the photoresist patterns on the lot of wafers as a mask, thereby forming circuit patterns on the corresponding mask on each shot area of each wafer. Then, by forming a further upper circuit pattern or the like, a semiconductor device or the like is manufactured. According to the above semiconductor device manufacturing method, a semiconductor device having an extremely fine circuit pattern can be obtained with good yield.

In addition, in the exposure apparatus of the embodiment of the invention, by forming predetermined patterns (circuit patterns, electrode patterns, and the like) on a panel (glass substrate), a liquid crystal display element as a microelectronic element can be obtained. Next, an example of the method at this time will be described with reference to the flowchart of fig. 13. As shown in the pattern forming step 401 of fig. 13, a so-called photolithography process is performed by using the exposure apparatus of the above embodiment to transfer and expose the pattern on the mask onto a photosensitive substrate (resist-coated glass substrate). By using the photolithography process, a predetermined pattern including a plurality of electrodes is formed on a photosensitive substrate. Thereafter, the exposed substrate is subjected to a developing process, an etching process, a resist stripping process, and the like to form a predetermined pattern on the substrate, and then the process proceeds to a color filter forming process 402.

Then, in the color filter forming process 402, three point combinations corresponding to red R (Red), green G (Green), and blue B (blue) are arranged in a matrix, or R, G, B three filters are arranged in a plurality of horizontal scanning directions to form color filters. Next, after the color filter forming process 402, a component (cell) assembling process 403 is performed. In the module assembling step 403, a liquid crystal panel (liquid crystal module) is assembled by using the substrate having the predetermined pattern obtained in the pattern forming step 401, the color filter obtained in the color filter forming step 402, and the like.

In the module assembling step 403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402 to manufacture a liquid crystal panel (liquid crystal module). Then, in the module assembling step 404, each component such as a circuit and a backlight unit for causing the assembled liquid crystal panel (liquid crystal module) to perform a display operation is mounted to complete the liquid crystal display module. According to the above method for manufacturing a liquid crystal display device, a liquid crystal display device having an extremely fine circuit pattern can be obtained with good productivity.

In addition, in the embodiment of fig. 1, the light emitted from the secondary light source is collected by the focusing optical system 9 and is overlapped to illuminate the mask M. However, the present invention is not limited to this embodiment. As a modification shown in fig. 16, an illumination field diaphragm (mask plate) and a relay optical system for forming an image of the illumination field diaphragm on the mask M may be disposed on the optical path between the focusing optical system 9 and the mask M. In this case, the focusing optical system 9 collects light emitted from the secondary light source and superimposes the light on the illumination field diaphragm, and the relay optical system forms an image of an opening (light passing portion) of the illumination field diaphragm on the mask M.

In addition, in the above-mentioned examples, KrF excimer laser light (wavelength: 248nm) or ArF excimer laser light (wavelength: 193nm) was used as the exposure light, but the present invention is not limited thereto. Other suitable laser sources, e.g. F for supplying laser light of 157nm wavelength₂Laser light sources, or lamp light sources that supply light sources other than laser light, such as ultraviolet light, e.g., I or g rays, are also suitable for use in the present invention. Next, although the present invention is described in the above embodiments by taking a projection optical system including an optical illumination device as an example, it is obvious that the present invention is also applicable to general optical illumination devices for illuminating an illuminated surface other than a mask.

In the above-described embodiment, a method of filling the optical path between the projection optical system and the photosensitive substrate with a medium (generally, a liquid) having a refractive index of more than 1.1 may be a so-called liquid immersion method. In this case, as a method of filling a liquid into an optical path between the projection optical system and the photosensitive substrate, a partial liquid filling method disclosed in International publication No. WO99/49504, a method of moving a stage holding an exposure object in a liquid bath disclosed in Japanese patent laid-open No. Hei 6-124873, a method of forming a liquid bath of a certain depth in a stage and holding a substrate therein, and the like can be used.

Further, as the liquid, it is transparent to exposure light and has a refractive index as high as possible, and it is preferable to use a stable substance for a projection optical system or a resist coated on the surface of a substrate. For example, when KrF excimer laser light or ArF excimer laser light is used as the exposure light, pure water or deionized water can be used as the liquid. Furthermore, use of F₂When laser light is used as exposure light, it is also possible to use a transparent F₂The laser beam is used as a liquid, for example, a fluorine-based liquid such as fluorine-based oil or perfluorinated polyether (PFPE).

Further, the present invention is also applicable to a twin stage type (twin stage type) exposure apparatus having two stages, which can independently move in the XY direction while respectively mounting a substrate to be processed such as a wafer, as disclosed in Japanese patent laid-open Nos. H10-163099, H10-214783, and 2000-505958.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An adjustment method of an optical illumination device that illuminates an illuminated surface with a specific polarization state in accordance with light emitted from a light source section, the adjustment method comprising the steps of:

a wavelength plate setting step of setting a crystal optical axis of the 1/4 wavelength plate at a predetermined angular position in an illumination optical path of the optical illumination device, and setting a crystal optical axis of the 1/2 wavelength plate at a predetermined angular position in an illumination optical path of the optical illumination device; and

the wavelength plate setting step is to set the crystal optical axis of the 1/4 wavelength plate at a desired position based on the detection result of the polarization state of light detected in the optical path between the polarization state switching means and the irradiated surface when the crystal optical axis of the 1/4 wavelength plate and the crystal optical axis of the 1/2 wavelength plate are changed, convert the incident elliptically polarized light into linearly polarized light, and set the crystal optical axis of the 1/2 wavelength plate at a reference position, convert the incident linearly polarized light into linearly polarized light having a polarization plane in a predetermined direction.

2. The method according to claim 1, wherein the optical axis of crystallization of the 1/4 wavelength plate is set at a first angular position at which the contrast of change in the Stacker parameter S1 component in the detection result is approximately maximum when the optical axis of crystallization of the 1/4 wavelength plate is changed, and the optical axis of crystallization of the 1/2 wavelength plate is set at a second angular position at which the contrast of change in the Stacker parameter S1 component in the detection result is approximately maximum or minimum when the optical axis of crystallization of the 1/2 wavelength plate is changed in a state in which the optical axis of crystallization of the 1/4 wavelength plate is set at the first angular position.

3. The method for adjusting an optical illumination device according to claim 2, further comprising the steps of:

an illumination pupil forming step of forming a predetermined light intensity distribution on a pupil surface of the optical illumination device or in the vicinity of the pupil surface, based on the light beam emitted from the light source section;

an illumination pupil changing step of changing at least one of a shape and a size of the predetermined light intensity distribution;

a wavelength plate resetting step of correcting and setting at least one of the crystal optical axis of the 1/4 wavelength plate and the crystal optical axis of the 1/2 wavelength plate according to a change of at least one of the shape and the size of the predetermined light intensity distribution.

4. Exposing a predetermined pattern onto a photosensitive substrate disposed on the irradiation surface via the optical illumination device adjusted by the adjustment method according to any one of claims 1 to 3.

5. The exposure apparatus according to claim 4, further comprising:

a projection optical system disposed in an optical path between a first setting surface set by the predetermined pattern and a second setting surface set by the photosensitive substrate, for forming an image of the predetermined pattern on the second setting surface;

pupil intensity distribution forming means for forming a predetermined light intensity distribution at a position at or near a pupil and a conjugate position of the projection optical system; and

pupil intensity distribution changing means for changing at least one of a shape and a size of the predetermined light intensity distribution.

6. The exposure apparatus according to claim 5, further comprising a polarization state changing means disposed in an optical path between the light source section and the irradiated surface for changing a polarization state of the light illuminated to the irradiated surface, wherein the pupil intensity distribution changing means changes at least one of a shape and a size of the predetermined light intensity distribution according to the predetermined pattern characteristic,

the polarization state changing means changes the polarization state of the light illuminated on the illuminated surface according to a change in at least one of the shape and the size of the predetermined light intensity distribution.

7. The exposure apparatus according to claim 6, wherein the polarization state changing means includes polarization state switching means for switching the polarization state of the light illuminating the irradiated surface between a specific polarization state and a non-polarization state,

wherein the polarization state switching means switches between the specific polarization state and the non-polarization state according to a change in at least one of a shape and a size of the predetermined light intensity distribution.

8. The exposure apparatus according to claim 7, wherein the pupil intensity distribution forming means forms two high light intensity distribution regions at intervals along a pitch direction of the line-and-space pattern formed on the mask,

the polarization state changing means sets the polarization state of the light illuminating the illuminated surface from the two high light intensity partial areas to a linear polarization state having a polarization plane in a direction substantially perpendicular to the pitch direction.

9. The exposure apparatus according to claim 8, wherein the two high light intensity partial regions are formed symmetrically to an optical axis of the optical illumination device, wherein a ratio of a diameter Φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter Φ of the pupil surface with the optical axis as a center is defined as σ o, σ o ═ Φ o/Φ p, where σ o satisfies the following condition:

0.7≤σo。

10. the exposure apparatus according to claim 9, wherein the two high light intensity partial regions are formed symmetrically to an optical axis of the optical illumination device, wherein a ratio Φ o/Φ p of a diameter Φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter Φ p of the pupil surface with respect to the optical axis as a center is defined as σ o, and a ratio Φ i/Φ p of a diameter Φ i of an inscribed circle inscribed in the two high light intensity partial regions and the diameter Φ p of the pupil surface with respect to the optical axis as a center is defined as σ i

0.5≤σi/σo。

11. The exposure apparatus according to claim 6, wherein the pupil intensity distribution forming means forms a high light intensity partial region substantially around the optical axis of the optical illumination device, and wherein the polarization state changing means sets the polarization state of the light illuminated from the high light intensity partial region to the illuminated surface to a linear polarization state having a polarization plane in a direction in which a line formed on the phase shift mask is substantially perpendicular to a pitch direction of the space.

12. The exposure apparatus according to claim 11, wherein a ratio of the size Φ of the high light intensity partial region to a diameter Φ p of the pupil surface is defined as σ, σ Φ/Φ p, where σ o satisfies the following condition:

σ≤0.4。

13. an exposure method, characterized by comprising the steps of:

an illumination step of illuminating a predetermined pattern via the optical illumination device adjusted by the adjustment method according to any one of claims 1 to 3; and

and an exposure step of exposing the predetermined pattern onto a photosensitive substrate disposed on the surface to be irradiated.

14. The exposure method according to claim 13, further comprising:

a projection step of forming the predetermined pattern image using a projection optical system;

a pupil intensity distribution forming step of forming a predetermined light intensity distribution at a position at or near a pupil and a conjugate position of the projection optical system; and

a pupil intensity distribution changing step for changing at least one of a shape and a size of the predetermined light intensity distribution.

15. The exposure method according to claim 14, wherein the pupil intensity distribution changing step further includes changing at least one of a shape and a size of the predetermined light intensity distribution according to the predetermined pattern characteristic, and changing a polarization state of the light illuminated to the illuminated surface according to the change in the at least one of the shape and the size of the predetermined light intensity distribution.

16. The exposure method according to claim 15, wherein the pupil intensity distribution forming step further includes forming two high light intensity distribution areas at intervals along a pitch direction of the line and space pattern formed on the mask, and setting a polarization state of light illuminating the illuminated surface from the two high light intensity distribution areas to a linear polarization state having a polarization plane in a direction substantially perpendicular to the pitch direction.

17. The exposure method according to claim 16, wherein the two high light intensity partial regions are formed symmetrically to an optical axis of the optical illumination device, wherein a ratio of a diameter Φ o of a circumscribed circle circumscribing the two high light intensity partial regions and a diameter Φ p of the pupil surface with the optical axis as a center is defined as σ o, σ o ═ Φ o/Φ p, where σ o satisfies the following condition:

0.7≤σo。

18. the exposure method according to claim 16, wherein the two high light intensity partial regions are formed symmetrically to an optical axis of the optical illumination device, wherein a ratio Φ o/Φ p of a diameter Φ o of an outer circle circumscribing the two high light intensity partial regions and a diameter Φ p of the pupil surface with respect to the optical axis as a center is defined as σ o, and a ratio Φ i/Φ p of a diameter Φ i of an inner circle inscribing the two high light intensity partial regions and the diameter Φ p of the pupil surface with respect to the optical axis as a center is defined as σ i

0.5≤σi/σo。