JP2005236088A - Illuminating optical device, aligner, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating optical device which can provide illumination conditions which are highly diverse regarding proper illumination conditions such as a secondary light source shape, light intensity and polarization state required for transferring a mask pattern with various characteristics truly when mounted on an aligner. <P>SOLUTION: The illuminating optical device illuminates an irradiation surface by optical flux from a light source (1). It has an illuminating pupil formation means (20 to 26, 6) for forming illuminating pupil distribution with light intensity distribution located in a first region, and light intensity distribution located in a second region on an illuminating pupil surface; and illuminating pupil control means (17, 23 and 24) for carrying out control for changing the shape of the first region and the shape of the second region independently from each other, and control for changing the polarization state of optical flux passing through the first region and the polarization state of optical flux passing through the second region independently from each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illumination optical apparatus, an exposure apparatus, and an exposure method, and more particularly to an illumination optical apparatus suitable for an exposure apparatus for manufacturing a microdevice such as a semiconductor element, an imaging element, a liquid crystal display element, and a thin film magnetic head in a lithography process. It is about.

  In a typical exposure apparatus of this type, a light beam emitted from a light source passes through a fly-eye lens (or micro fly-eye lens) as an optical integrator, and is used as a substantial surface light source composed of a number of light sources. A next light source (generally, a predetermined light intensity distribution formed on the illumination pupil plane) is formed. The light beam from the secondary light source is limited through an aperture stop disposed in the vicinity of the rear focal plane of the fly-eye lens, and then enters the condenser lens.

  The light beam condensed by the condenser lens illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask pattern forms an image on the wafer via the projection optical system. Thus, the mask pattern is projected and exposed (transferred) onto the wafer. The pattern formed on the mask is highly integrated, and it is essential to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

  Therefore, a circular secondary light source is formed on the rear focal plane of the fly-eye lens, and the size thereof is changed to change the illumination coherency σ (σ value = aperture aperture diameter / projection optical system pupil diameter, or σ Attention has been focused on a technique of changing the value = the exit numerical aperture of the illumination optical system / the incident numerical aperture of the projection optical system. Further, attention has been focused on a technique for forming an annular or quadrupolar secondary light source on the rear focal plane of the fly-eye lens to improve the depth of focus and resolution of the projection optical system.

  In the conventional exposure apparatus as described above, normal circular illumination based on a circular secondary light source is performed according to the pattern characteristics of the mask, or modified illumination based on a ring-shaped or quadrupolar secondary light source (ring Band lighting and quadrupole lighting). However, it is possible to realize a variety of illumination conditions necessary for faithfully transferring a mask pattern having various characteristics, such as the shape, light intensity, and polarization state of the secondary light source. There wasn't.

  The present invention has been made in view of the above-described problems. For example, when mounted on an exposure apparatus, an appropriate illumination condition necessary for faithfully transferring a mask pattern having various characteristics, such as a secondary illumination. It is an object of the present invention to provide an illumination optical apparatus that can realize a wide variety of illumination conditions regarding the shape, light intensity, polarization state, and the like of a light source.

  Further, the present invention has been realized according to the pattern characteristics of the mask, using an illumination optical device that can realize appropriate illumination conditions necessary for faithfully transferring a mask pattern having various characteristics, for example. An object of the present invention is to provide an exposure apparatus and an exposure method capable of performing good exposure under appropriate illumination conditions.

In order to solve the above problems, in the first embodiment of the present invention, in the illumination optical device that illuminates the illuminated surface with the light beam from the light source,
Illumination pupil forming means for forming an illumination pupil distribution having a light intensity distribution located in the first region on the illumination pupil plane and a light intensity distribution located in the second region;
Control for changing the shape of the first region and the shape of the second region independently of each other, and the polarization state of the light beam passing through the first region and the polarization state of the light beam passing through the second region are independent of each other. There is provided an illumination optical apparatus comprising illumination pupil control means for performing control to change to

  According to a preferred aspect of the first aspect, the splitting element for splitting the light flux from the light source and one light flux split through the splitting element are guided to the first region on the illumination pupil plane. And the second optical system for guiding the other light beam split through the splitting element to the second region on the illumination pupil plane along an optical path different from that of the first optical system. And. In this case, it is preferable to include an illuminance uniforming unit that is disposed in an optical path between the light source and the splitting element to substantially uniform the illuminance distribution in the vicinity of the splitting element. In addition, it is preferable that the splitting element guides the light flux from the light source to the first optical system and the second optical system by dividing the wavefront.

  According to a preferred aspect of the first aspect, the illumination pupil forming means is a first for converting the incident light beam arranged in the optical path of the first optical system into a light beam corresponding to the first region. A light beam conversion element, a second light beam conversion element disposed in the optical path of the second optical system for converting an incident light beam into a light beam corresponding to the second region, and a light beam from the first light beam conversion element And an optical integrator for forming the illumination pupil distribution on the illumination pupil plane based on the light flux from the second light flux conversion element. The illumination pupil control means is arranged in the optical path of the first optical system and is arranged in the optical path of the second optical system, and first shape changing means for changing the shape of the first region. And second shape changing means for changing the shape of the second region.

  Further, according to a preferred aspect of the first aspect, the first shape changing means has a first axicon system disposed in an optical path between the first light flux conversion element and the optical integrator, The two shape changing means has a second axicon system disposed in an optical path between the second light flux conversion element and the optical integrator, and the first axicon system and the second axicon system have a concave cross section. A first prism having a refracting surface, and a second prism having a refracting surface with a convex cross section formed substantially complementary to the refracting surface with the concave cross section of the first prism, The distance from the second prism is variable. In this case, the first shape changing unit includes a first variable magnification optical system disposed in an optical path between the first light beam conversion element and the optical integrator, and the second shape changing unit includes the first shape changing unit, It is preferable to have a second variable magnification optical system disposed in the optical path between the second light flux conversion element and the optical integrator.

  According to a preferred aspect of the first aspect, the illumination pupil control means is a first polarization for changing the polarization state of a light beam that is disposed in the optical path of the first optical system and passes through the first region. State changing means and second polarization state changing means for changing the polarization state of a light beam that is disposed in the optical path of the second optical system and passes through the second region. In this case, the first polarization state changing unit includes a first phase member that is arranged in the optical path of the first optical system and changes the polarization direction of the incident linearly polarized light as necessary. The bi-polarization state changing means preferably has a second phase member that is arranged in the optical path of the second optical system and changes the polarization direction of the linearly polarized light that is incident as necessary. The first polarization state changing means is configured to be detachable with respect to the optical path of the first optical system, and has a first depolarization element for depolarizing incident light as necessary. The second polarization state changing means includes a second depolarization element configured to be detachable from the optical path of the second optical system and depolarizing incident light as necessary. It is preferable.

  According to a preferred aspect of the first aspect, the illumination pupil forming means is a first for converting the incident light beam arranged in the optical path of the first optical system into a light beam corresponding to the first region. The first polarization state changing means, comprising: a light beam conversion element; and a second light beam conversion element disposed in the optical path of the second optical system for converting an incident light beam into a light beam corresponding to the second region. Includes a first phase member arranged in an optical path between the splitting element and the first light flux conversion element for changing a polarization direction of incident linearly polarized light as necessary, the splitting element, and the first A first depolarizing element that is detachably disposed in the optical path between the light flux converting element and depolarizes incident light as necessary, and the second polarization state changing means includes: , In the optical path between the splitting element and the second light flux converting element A second phase member for changing the polarization direction of the linearly polarized light that is placed and incident, if necessary, and removably disposed in the optical path between the splitting element and the first light beam conversion element. A second depolarizing element for depolarizing incident light as necessary is provided.

  Further, according to a preferred aspect of the first aspect, the illumination pupil control means passes through the second area and first light intensity changing means for changing the light intensity of the light beam passing through the first area. Second light intensity changing means for changing the light intensity of the light beam. In this case, it is preferable that the first light intensity changing unit is disposed in the optical path of the first optical system, and the second light intensity changing unit is disposed in the optical path of the second optical system. In this case, the first light intensity changing means has at least one dimming means that can be selectively inserted into and removed from the optical path of the first optical system, and the second light intensity changing means is the first light intensity changing means. It is preferable to have at least one dimming means that can be selectively inserted into and removed from the optical path of the two optical systems.

  According to a preferred aspect of the first aspect, the first light flux conversion element and the second light flux conversion element are configured to be interchangeable with respect to the optical path. The first region is preferably a region including an optical axis on the illumination pupil plane, and the second region is a region away from the optical axis on the illumination pupil plane. In this case, the second region is preferably ring-shaped or multipolar. It is preferable that the optical system further includes a light guide optical system for guiding the light beam from the optical integrator to the irradiated surface.

In the second embodiment of the present invention, in the illumination optical device that illuminates the irradiated surface with the light beam from the light source,
Illumination pupil forming means for forming an illumination pupil distribution having a light intensity distribution located in the first region on the illumination pupil plane and a light intensity distribution located in the second region;
The illumination pupil forming means includes
A splitting element disposed in an optical path between the light source and the illumination pupil plane;
A first optical system for guiding one light beam divided through the dividing element to a first region on the illumination pupil plane;
A second optical system for guiding the other light beam split through the splitting element to a second region on the illumination pupil plane along an optical path different from that of the first optical system;
A combining element disposed in an optical path between the dividing element and the illumination pupil plane for combining the optical axis of the first optical system and the optical axis of the second optical system;
The first optical system includes a first light beam conversion element for converting an incident light beam into a light beam corresponding to the first region,
The second optical system includes an illumination optical apparatus including a second light beam conversion element for converting an incident light beam into a light beam corresponding to the second region.

  According to a preferred aspect of the second form, the illumination pupil forming means causes the illumination pupil plane to split the light beam split through the splitting element along an optical path different from that of the first optical system and the second optical system. A third optical system for guiding to the third region above is further provided.

  According to a third aspect of the present invention, there is provided an exposure apparatus comprising the illumination optical apparatus according to the first or second aspect for illuminating a mask, and exposing the pattern of the mask onto a photosensitive substrate. . In this case, the image forming apparatus further includes a projection optical system for forming an image of the mask pattern on the photosensitive substrate, and the pupil plane of the illumination optical device is positioned substantially conjugate with the pupil position of the projection optical system. Preferably it is.

  According to a fourth aspect of the present invention, the method includes an illumination step of illuminating a mask using the illumination optical apparatus of the first or second aspect, and an exposure step of exposing the pattern of the mask onto a photosensitive substrate. An exposure method is provided. In this case, the exposure step includes a projection step of forming an image of the mask pattern on the photosensitive substrate using a projection optical system, and the pupil plane of the illumination optical device is a pupil position of the projection optical system. It is preferable that it is positioned almost conjugate with.

  In the illumination optical apparatus according to the present invention, for example, the light intensity distribution and the second position located in the first region on the illumination pupil plane are obtained by the action of a light beam conversion element such as a diffractive optical element or an optical integrator such as a micro fly's eye lens. An illumination pupil distribution having a light intensity distribution located in the region, for example, a pentapolar secondary light source is formed. And control which changes the shape of the 1st field and the shape of the 2nd field mutually independently by operation of an axicon system, a variable magnification optical system, etc., for example is performed. Further, for example, the polarization state of the light beam passing through the first region and the polarization state of the light beam passing through the second region are made independent of each other by the action of a phase member such as a half-wave plate or a depolarizer (depolarization element). Control to change to.

  Therefore, for example, when the illumination optical apparatus of the present invention is mounted on an exposure apparatus, appropriate illumination conditions necessary for faithfully transferring a mask pattern having various characteristics, such as the shape, light intensity, and polarization state of the secondary light source A variety of lighting conditions can be realized. In addition, in the exposure apparatus and exposure method using the illumination optical apparatus of the present invention, it is possible to realize appropriate illumination conditions necessary for faithfully transferring a mask pattern having various characteristics. Accordingly, it is possible to perform good exposure under appropriate illumination conditions realized accordingly, and thus it is possible to manufacture a good device with high throughput.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a view schematically showing the overall configuration of an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing the internal configuration of the control unit in FIG. In FIG. 1, the Z axis along the normal direction of the wafer W, which is a photosensitive substrate, the Y axis in the direction parallel to the plane of FIG. 1 in the plane of the wafer W, and the plane of the wafer W in FIG. The X axis is set in the direction perpendicular to the paper surface.

  Referring to FIG. 1, the exposure apparatus of this embodiment includes a light source 1 for supplying exposure light (illumination light). As the light source 1, for example, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, or the like can be used. A substantially parallel light beam emitted from the light source 1 along the + Z direction has a rectangular cross section extending along the X direction and is incident on the beam expander 2 including a pair of lenses 2a and 2b. Each lens 2a and 2b has a negative refracting power and a positive refracting power in the plane of FIG. 1 (in the YZ plane), respectively.

  Accordingly, the light beam incident on the beam expander 2 is enlarged in the plane of FIG. 1 and shaped into a light beam having a predetermined rectangular cross section. A substantially parallel light beam via the beam expander 2 as a shaping optical system is guided to the control unit 5 after being deflected by the mirror 3 in the + Y direction. The mirror 3 is configured to be tiltable with respect to the optical axis AX by the action of the mirror driving unit 4. The mirror driving unit 4 controls the tilting of the mirror 3 based on signals from detectors 19a and 19b described later.

  Referring to FIG. 2, the light beam guided to the control unit 5 of the present embodiment is incident on a fly-eye lens 11 made up of a number of positive lens elements that are arranged vertically and horizontally and densely, for example. The light beam incident on the fly-eye lens 11 is two-dimensionally divided by a large number of lens elements, and a large number of light sources are formed at or near the rear focal plane. Light beams from multiple light sources formed on the rear focal plane of the fly-eye lens 11 or in the vicinity thereof are condensed through the condenser lens 12 and then have a substantially uniform illuminance distribution at the rear focal position or in the vicinity thereof. Form Teruno.

  A right-angle prism 13 as a dividing element is disposed at or near the rear focal position of the condenser lens 12. Therefore, among the light beams incident on the right-angle prism 13 through the condenser lens 12, the light beam incident on the first reflecting surface 13a is reflected in the -Z direction and guided to the first optical system, and the second reflecting surface 13b. Is reflected in the + Z direction and guided to the second optical system. The first optical system and the second optical system have basically the same configuration, but only the characteristics of the diffractive optical element 20 described later are different from each other.

  Therefore, in FIG. 2, a reference numeral “a” is attached to an element constituting the first optical system, and a reference numeral “b” is attached to the same reference numeral for a corresponding element constituting the second optical system. Yes. Hereinafter, in the description of the configurations and operations of the first optical system and the second optical system, reference numerals corresponding to the second optical system are indicated in parentheses. The light beam guided to the first optical system (second optical system) enters the beam splitter 15a (15b) via the relay lens 14a (14b). Most of the light beam reflected in the + Y direction by the beam splitter 15a (15b) enters the polarization state changing unit 17a (17b) via the relay lens 16a (16b).

  The polarization state changing unit 17a (17b) includes, in order from the light source side, a quarter-wave plate 17aa (17ba) configured to be detachable with respect to the optical path, and 1 / configured to be detachable with respect to the optical path. The two-wavelength plate 17ab (17bb) and a depolarizer (non-polarizing element) 17ac (17bc) configured to be detachable with respect to the optical path. The detailed configuration and operation of the polarization state changing unit 17a (17b) will be described later.

  On the other hand, the light beam transmitted through the beam splitter 15a (15b) reaches the detector 19a (19b) via the relay lens 18a (18b). Here, the rear focal position of the condenser lens 12 and the detection surface of the detector 19a (19b) are arranged optically almost conjugate via the relay lens 14a (14b) and the relay lens 18a (18b). Yes. Thus, the relay lens 18a (18b) and the detector 19a (19b) detect the light amount (light intensity) of the light beam guided to the first optical system (second optical system), and consequently the light amount splitting ratio in the right-angle prism 13. A light amount detection system for detecting the light is configured.

  The output signal of the detector 19a (19b) is supplied to the mirror driving unit 4. As described above, the mirror driving unit 4 tilts the mirror 3 by a predetermined angle based on the signals from the detectors 19a and 19b, and sets the illumination field formed in the vicinity of the right-angle prism 13 in the optical axis orthogonal direction (Z direction). )). In other words, the amount of light splitting ratio in the right-angle prism 13 changes due to the tilt of the mirror 3 based on the command from the mirror drive unit 4, and consequently the light amount (light intensity) of the light beam guided to the first optical system and the second optical system. The ratio with the light quantity (light intensity) of the guided light flux changes.

  The light beam that has passed through the polarization state changing unit 17a (17b) enters the afocal lens 21a (21b) through the diffractive optical element 20a (20b). Here, the reflecting surface 13a (13b) of the right-angle prism 13 and the diffractive optical element 20a (20b) are arranged optically almost conjugate via the relay lens 14a (14b) and the relay lens 16a (16b). Yes. The afocal lens 21a (21b) has a front focal position substantially coincident with the position of the diffractive optical element 20a (20b), and the rear focal position and a position of a predetermined surface 22a (22b) indicated by a broken line in the figure. Are afocal systems (non-focal optical systems) set so as to substantially match.

  In general, a diffractive optical element is formed by forming a step having a pitch of the wavelength of exposure light (illumination light) on a substrate, and has a function of diffracting an incident beam to a desired angle. Specifically, the first diffractive optical element 20a disposed in the optical path of the first optical system has a circular shape in its far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. It has a function of forming a light intensity distribution having a shape. On the other hand, the second diffractive optical element 20b disposed in the optical path of the second optical system has a quadrupole shape in its far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. It has a function of forming a light intensity distribution.

  Accordingly, the substantially parallel light beam incident on the diffractive optical element 20a (20b) as the light beam conversion element forms a circular (quadrupole) light intensity distribution on or near the pupil surface of the afocal lens 21a (21b). Then, it becomes a substantially parallel light beam and is emitted from the afocal lens 21a (21b). In the optical path between the front lens group 21aa (21ba) and the rear lens group 21ab (21bb) of the afocal lens 21a (21b), a conical axicon system 23a (23b) is provided on or near the pupil plane. The detailed configuration and operation will be described later.

  Hereinafter, in order to simplify the description, the basic configuration and operation will be described ignoring the operation of the conical axicon system 23a (23b). The light beam that has passed through the afocal lens 21a (21b) is emitted from the first optical system (second optical system) through the zoom lens 24a (24b) for varying the σ value and the relay lens 25a (25b). The light beams respectively emitted from the first optical system and the second optical system are incident on a micro fly's eye lens (or fly eye lens) 6 as an optical integrator via a condensing optical system 26.

  In the control unit 5, the incident surface of the fly-eye lens 11, the reflection surface 13a (13b) of the right-angle prism 13, the detection surface of the detector 19a (19b), the diffractive optical element 20a (20b), and a predetermined surface 22a (22b) and the rear focal plane of the relay lens 25a (25b) (or the front focal plane of the condensing optical system 26) are optically conjugate. Further, the rear focal plane (or exit surface) of the fly-eye lens 11, the beam splitter 15a (15b), the conical axicon system 23a (23b), and the rear focal plane (or relay lens) of the zoom lens 24a (24b). 25a (the front focal plane of 25b) is optically nearly conjugate.

  The micro fly's eye lens 6 is an optical element composed of a large number of micro lenses having positive refractive power, which are arranged vertically and horizontally and densely, for example. In general, a micro fly's eye lens is configured by, for example, performing etching treatment on a plane-parallel plate to form a micro lens group. Here, each micro lens constituting the micro fly's eye lens is smaller than each lens element constituting the fly eye lens. Further, unlike a fly-eye lens composed of lens elements isolated from each other, a micro fly-eye lens is formed integrally with a large number of micro lenses (micro refractive surfaces) without being isolated from each other.

  However, the micro fly's eye lens is the same wavefront division type optical integrator as the fly eye lens in that lens elements having positive refractive power are arranged vertically and horizontally. The position of the predetermined surface 22a (22b) is arranged at or near the front focal position of the zoom lens 24a (24b), and the rear focal position of the zoom lens 24a (24b) and the front focal position of the relay lens 25a (25b). Is almost the same. Further, the rear focal position of the relay lens 25a (25b) is disposed at or near the front focal plane of the condensing optical system 26, and the micro fly's eye lens 6 is disposed at or near the rear focal position of the condensing optical system 26. An incident surface is arranged.

  In other words, the zoom lens 24a (24b), the relay lens 25a (25b), and the condensing optical system 26 substantially have a Fourier transform relationship between the predetermined surface 22a (22b) and the incident surface of the micro fly's eye lens 6. In other words, the pupil plane of the afocal lens 21a (21b) and the incident plane of the micro fly's eye lens 6 are optically substantially conjugate. Therefore, on the incident surface of the micro fly's eye lens 6, a circular light intensity distribution formed on or near the pupil surface of the first afocal lens 21a in the first optical system, and in the second optical system. A pentapolar illumination field is formed by combining with a quadrupolar light intensity distribution formed on or near the pupil plane of the second afocal lens 21b. The overall shape of the pentapolar illumination field changes in a similar manner depending on the focal length of the zoom lens 24a (24b).

  Each microlens constituting the micro fly's eye lens 6 has a rectangular cross section similar to the shape of the illumination field to be formed on the mask M (and thus the shape of the exposure region to be formed on the wafer W). A light beam incident on the micro fly's eye lens 6 is two-dimensionally divided by a large number of minute lenses, and is formed on the incident surface of the micro fly's eye lens 6 on the rear focal plane or in the vicinity thereof (and on the illumination pupil plane). A secondary light source having almost the same light intensity distribution as that of the illumination field, that is, a substantially planar light source 40a having a circular shape centered on the optical axis AX, for example, as shown in FIG. In addition, a pentode-shaped secondary light source 40 composed of four arc-shaped substantial surface light sources 40b1 to 40b4 is formed.

  A light beam from a quinpole secondary light source (illumination pupil distribution) formed on the rear focal plane of the micro fly's eye lens 6 or in the vicinity thereof passes through a beam splitter 7a and a condenser optical system 8, and then is mask blind 9 Are illuminated in a superimposed manner. Thus, a rectangular illumination field corresponding to the shape and focal length of each microlens constituting the micro fly's eye lens 6 is formed on the mask blind 9 as an illumination field stop. The internal configuration and operation of the polarization monitor 7 incorporating the beam splitter 7a will be described later. The light beam that has passed through the rectangular opening (light transmitting portion) of the mask blind 9 receives the light condensing action of the imaging optical system 10 and then illuminates the mask M on which a predetermined pattern is formed in a superimposed manner.

  That is, the imaging optical system 10 forms an image of the rectangular opening of the mask blind 9 on the mask M. The light flux that has passed through the pattern of the mask M held by the mask stage MS forms an image of the mask pattern on the wafer (photosensitive substrate) W held by the wafer stage WS via the projection optical system PL. Here, the rear focal plane of the micro fly's eye lens 6 or the illumination pupil plane in the vicinity thereof is positioned substantially conjugate with the pupil position of the projection optical system PL. Thus, by performing batch exposure or scan exposure while driving and controlling the wafer W two-dimensionally in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, each exposure region of the wafer W is masked. M patterns are sequentially exposed.

  In the polarization state changing unit 17a (17b), the quarter wave plate 17aa (17ba) is configured such that the crystal optical axis is rotatable around the optical axis AX, and the incident elliptically polarized light is converted into linearly polarized light. Convert to light. The half-wave plate 17ab (17bb) is configured such that the crystal optical axis is rotatable about the optical axis AX, and changes the polarization plane of incident linearly polarized light. The depolarizer 17ac (17bc) is composed of a wedge-shaped quartz prism and a wedge-shaped quartz prism having complementary shapes. The quartz prism and the quartz prism are configured to be detachable with respect to the illumination optical path as an integral prism assembly.

  When a KrF excimer laser light source or an ArF excimer laser light source is used as the light source 1, the light emitted from these light sources typically has a degree of polarization of 95% or more, and the quarter wavelength plate 17aa (17ba) Nearly linearly polarized light is incident. However, when a right-angle prism as a back reflecting mirror is interposed in the optical path between the light source 1 and the polarization state changing unit 17a (17b), the polarization plane of incident linearly polarized light coincides with the P polarization plane or the S polarization plane. If not, linearly polarized light is changed to elliptically polarized light by total reflection at the right-angle prism.

  In the polarization state changing unit 17a (17b), for example, even if elliptically polarized light is incident due to total reflection from a right-angle prism, linearly polarized light converted by the action of the quarter-wave plate 17aa (17ba). Is incident on the half-wave plate 17ab (17bb). When the crystal optical axis of the half-wave plate 17ab (17bb) is set to make an angle of 0 degree or 90 degrees with respect to the plane of polarization of the linearly polarized light that is incident on the half-wave plate 17ab (17bb), The incident linearly polarized light passes through without changing the plane of polarization.

  Further, when the crystal optical axis of the half-wave plate 17ab (17bb) is set to make an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that is incident, the light enters the half-wave plate 17ab (17bb). The linearly polarized light is converted into linearly polarized light whose polarization plane is changed by 90 degrees. Further, when the crystal optical axis of the crystal prism of the depolarizer 17ac (17bc) is set to form an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light incident thereon, the linearly polarized light incident on the crystal prism is not polarized. It is converted (unpolarized) into state light.

  In the polarization state changing unit 17a (17b), when the depolarizer 17ac (17bc) is positioned in the illumination optical path, the crystal optical axis of the crystal prism makes an angle of 45 degrees with respect to the polarization plane of the linearly polarized light that is incident. It is configured. Incidentally, when the crystal optical axis of the crystal prism is set to make an angle of 0 degrees or 90 degrees with respect to the plane of polarization of the linearly polarized light incident thereon, the plane of polarization of the linearly polarized light incident on the crystal prism changes. It passes without any changes. Further, when the crystal optical axis of the half-wave plate 17ab (17bb) is set to make an angle of 22.5 degrees with respect to the plane of polarization of the linearly polarized light that is incident, the half-wave plate 17ab (17bb) The linearly polarized light incident on is converted into light in a non-polarized state including a linearly polarized light component that passes through without changing its polarization plane and a linearly polarized light component whose polarization plane changes by 90 degrees.

  In the polarization state changing unit 17a (17b), as described above, linearly polarized light is incident on the half-wave plate 17ab (17bb). However, in order to simplify the following description, in FIG. It is assumed that light of linearly polarized light (hereinafter referred to as “Z-direction polarized light”) having a polarization direction (electric field direction) is incident on the half-wave plate 17ab (17bb). When the depolarizer 17ac (17bc) is positioned in the illumination optical path, an angle of 0 degree or 90 degrees with respect to the polarization plane (polarization direction) of the Z-direction polarization incident on the crystal optical axis of the half-wave plate 17ab (17bb) In this case, the Z-polarized light incident on the half-wave plate 17ab (17bb) passes through the Z-polarized light without changing the polarization plane and enters the quartz prism of the depolarizer 17ac (17bc). To do. The crystal optical axis of the quartz prism is set to make an angle of 45 degrees with respect to the polarization plane of the incident Z-direction polarized light. Therefore, the Z-polarized light incident on the quartz prism is converted into unpolarized light. Is done.

  The light depolarized through the quartz prism enters the diffractive optical element 20a (20b) in a non-polarized state through the quartz prism as a compensator for compensating the traveling direction of the light. On the other hand, if the crystal optical axis of the half-wave plate 17ab (17bb) is set to form an angle of 45 degrees with respect to the polarization plane of the Z-direction polarized light that is incident, it enters the half-wave plate 17ab (17bb). The Z-polarized light has a polarization plane changed by 90 degrees, and becomes linearly polarized light (hereinafter referred to as “X-direction polarized light”) having a polarization direction (electric field direction) in the X direction in FIG. The light enters the quartz prism (17bc). Since the crystal optical axis of the quartz prism is set to make an angle of 45 degrees with respect to the polarization plane of the incident X-direction polarized light, the X-direction polarized light incident on the quartz prism is converted into unpolarized light. The light is converted and enters the diffractive optical element 20a (20b) through the quartz prism in an unpolarized state.

  On the other hand, when the depolarizer 17ac (17bc) is retracted from the illumination optical path, the angle of 0 degree or 90 degrees with respect to the polarization plane of the Z-direction polarization incident on the crystal optical axis of the half-wave plate 17ab (17bb) Is set such that the Z-polarized light incident on the half-wave plate 17ab (17bb) passes through the Z-polarized light without changing the polarization plane, and the diffractive optical element 20a ( 20b). On the other hand, if the crystal optical axis of the half-wave plate 17ab (17bb) is set to form an angle of 45 degrees with respect to the polarization plane of the Z-direction polarized light that is incident, it enters the half-wave plate 17ab (17bb). The Z-polarized light changes its polarization plane by 90 degrees to become X-directional polarized light, and enters the diffractive optical element 20a (20b) in the X-directional polarization state.

  As described above, in the polarization state changing unit 17a (17b), the depolarizer 17ac (17bc) is inserted and positioned in the illumination optical path so that light in the non-polarized state is incident on the diffractive optical element 20a (20b). Can do. Further, the depolarizer 17ac (17bc) is retracted from the illumination optical path, and an angle of 0 degrees or 90 degrees is formed with respect to the polarization plane of the Z-direction polarization incident on the crystal optical axis of the half-wave plate 17ab (17bb). By setting, light in the Z-direction polarization state can be incident on the diffractive optical element 20a (20b). Further, by retracting the depolarizer 17ac (17bc) from the illumination optical path and setting the crystal optical axis of the half-wave plate 17ab (17bb) to be 45 degrees with respect to the polarization plane of the Z direction polarization, Light in the X direction polarization state can be incident on the diffractive optical element 20a (20b).

  In other words, the diffractive optical element 20a (20b) is obtained by the action of the polarization state changing unit 17a (17b) including the quarter-wave plate 17aa (17ba), the half-wave plate 17ab (17bb), and the depolarizer 17ac (17bc). ), The polarization state of light passing through the circular surface light source 40a (quadrupole surface light sources 40b1 to 40b4) of the secondary light source 40, and the linear polarization state and the non-polarization state. In the case of a linear polarization state, it can be switched between mutually orthogonal polarization states (between Z direction polarization and X direction polarization).

  In general, the polarization state of the incident light to the diffractive optical element 20a (20b) is set to a linear polarization state having a polarization direction in an arbitrary direction by the action of the half-wave plate 17ab (17bb). You can also. Further, in the polarization state changing unit 17a (17b), the half-wave plate 17ab (17bb) and the depolarizer 17ac (17bc) are both retracted from the illumination optical path, and the crystal optical axis of the quarter-wave plate 17aa (17ba) is adjusted. By setting so as to make a predetermined angle with respect to the incident elliptically polarized light, light in a circularly polarized state can be made incident on the diffractive optical element 20a (20b).

  Next, the conical axicon system 23a (23b) includes, in order from the light source side, a first prism member having a flat surface directed toward the light source side (light incident side) and a concave conical refractive surface directed toward the mask side (light emission side). 23aa (23ba) and a second prism member 23ab (23bb) having a plane facing the mask side and a convex conical refracting surface facing the light source. The concave conical refracting surface of the first prism member 23aa (23ba) and the convex conical refracting surface of the second prism member 23ab (23bb) are complementarily formed so as to be in contact with each other. . Further, at least one of the first prism member 23aa (23ba) and the second prism member 23ab (23bb) is configured to be movable along the optical axis AX, and the first prism member 23aa (23ba) has a concave conical shape. The distance between the refracting surface and the convex conical refracting surface of the second prism member 23ab (23bb) is variable.

  Here, when the concave conical refracting surface of the first prism member 23aa (23ba) and the convex conical refracting surface of the second prism member 23ab (23bb) are in contact with each other, the conical axicon system 23a (23b) is There is no influence on the circular (quadrupole) surface light source 40a (40b) that functions as a plane-parallel plate and constitutes the formed secondary light source 40. However, when the concave conical refracting surface of the first prism member 23aa (23ba) and the convex conical refracting surface of the second prism member 23ab (23bb) are separated from each other, the conical axicon system 23a (23b) becomes a so-called beam expander. Function. Therefore, the angle of the incident light beam on the predetermined surface 22a (22b) changes with the change in the interval of the conical axicon system 23a (23b).

  FIG. 4 is a diagram for explaining the action of the conical axicon system on the quadrupole surface light source constituting the secondary light source. Referring to FIG. 4, the most formed in a state where the distance between the conical axicon system 23b in the second optical system is zero and the focal length of the zoom lens 24b is set to the minimum value (hereinafter referred to as “standard state”). The small quadrupole surface light sources 41b1 to 41b4 expand the interval of the conical axicon system 23b from zero to a predetermined value, thereby increasing the width (the outer diameter that is the diameter of the circumscribed circle and the inner diameter that is the diameter of the inscribed circle). (Indicated by a double-headed arrow in the figure) does not change, and changes to the four-pole surface light sources 42b1 to 42b4 whose outer diameter and inner diameter are both enlarged. In other words, the ring zone ratio (inner diameter / outer diameter) and size (outer diameter) both change without the width of the quadrupole surface light source changing due to the action of the conical axicon system 23b.

  On the other hand, although not shown, the quadrupole surface light source formed in the standard state of the zoom lens 24b has a similar overall shape by increasing the focal length of the zoom lens 24b from a minimum value to a predetermined value. It changes to a quadrupole surface light source that is enlarged. In other words, due to the zooming action of the zoom lens 24b, the entire quadrupole surface light sources 40b1 to 40b4 are enlarged or reduced in a similar manner, and the width and size (outer diameter) are changed without changing the annular ratio. ) Both change. Similarly, the circular surface light source 40a is similarly enlarged or reduced by the zooming action of the zoom lens 24a in the first optical system. Note that, by the action of the conical axicon system 23a in the first optical system, the circular surface light source 40a is converted into a ring-shaped surface light source as necessary, and its width (1/2 of the difference between the outer diameter and the inner diameter) is converted. ) Can be changed without changing the ring zone ratio (inner diameter / outer diameter) and size (outer diameter).

  FIG. 5 is a diagram for explaining the cooperative action of the conical axicon system and the zoom lens with respect to the pentapolar secondary light source. In the present embodiment, the zoom lens 24a in the first optical system has a zooming action of the zoom lens 24a, so that the circular surface light source is made relatively small as shown in FIG. 5A, or as shown in FIG. 5B. The circular surface light source can be made relatively large. In addition, the colloidal axicon system 23b and the zoom lens 24b in the second optical system cooperate with each other to keep the size (outer diameter) constant, and as shown in FIG. 5A, a quadrupole surface light source. Can be made relatively large, or the width of the quadrupole surface light source can be made relatively small as shown in FIG.

  That is, without being limited to the example shown in FIG. 5, generally, a circular surface light source is used independently of a quadrupole surface light source by the zooming action of the zoom lens 24a in the first optical system. It can be enlarged or reduced in a similar manner. In addition, due to the cooperative action of the conical axicon system 23b and the zoom lens 24b in the second optical system, the width and annular ratio (inner diameter / outer ratio) of the quadrupole surface light source are independent of the circular surface light source. Shape parameters such as (diameter) and size (outer diameter) can be changed. Furthermore, if necessary, a circular surface light source is converted into a ring-shaped surface light source by the cooperative action of the conical axicon system 23a and the zoom lens 24a in the first optical system, and the width, the ring-zone ratio ( Shape parameters such as (inner diameter / outer diameter) and size (outer diameter) can be changed.

  FIG. 6 is a perspective view schematically showing an internal configuration of the polarization monitor of FIG. Referring to FIG. 6, the polarization monitor 7 includes a first beam splitter 7 a disposed in the optical path between the micro fly's eye lens 6 and the condenser optical system 8. The first beam splitter 7a has a form of a non-coated parallel flat plate (that is, a bare glass) formed of, for example, quartz glass, and has a function of extracting reflected light having a polarization state different from the polarization state of incident light from the optical path. .

  The light extracted from the optical path by the first beam splitter 7a enters the second beam splitter 7b. Similar to the first beam splitter 7a, the second beam splitter 7b has a form of a non-coated parallel flat plate made of, for example, quartz glass, and generates reflected light having a polarization state different from the polarization state of incident light. It has a function. The P-polarized light for the first beam splitter 7a is set to be S-polarized light for the second beam splitter 7b, and the S-polarized light for the first beam splitter 7a is set to be P-polarized light for the second beam splitter 7b.

  The light transmitted through the second beam splitter 7b is detected by the first light intensity detector 7c, and the light reflected by the second beam splitter 7b is detected by the second light intensity detector 7d. Outputs of the first light intensity detector 7c and the second light intensity detector 7d are respectively supplied to a control unit (not shown). The controller drives the quarter-wave plate 17aa (17ba), the half-wave plate 17ab (17bb), and the depolarizer 17ac (17bc) constituting the polarization state changing unit 17a (17b) as necessary.

  As described above, in the first beam splitter 7a and the second beam splitter 7b, the reflectance for P-polarized light and the reflectance for S-polarized light are substantially different. Therefore, in the polarization monitor 7, the reflected light from the first beam splitter 7a is, for example, about 10% of the S-polarized component of the incident light to the first beam splitter 7a (the S-polarized component with respect to the first beam splitter 7a, P-polarized component for the two beam splitter 7b) and P-polarized component of about 1% of the incident light to the first beam splitter 7a (P-polarized component for the first beam splitter 7a and S-polarized light for the second beam splitter 7b) Component).

  The reflected light from the second beam splitter 7b is, for example, a P-polarized component of about 10% × 1% = 0.1% of the incident light to the first beam splitter 7a (a P-polarized component with respect to the first beam splitter 7a). The S-polarized component for the second beam splitter 7b) and the S-polarized component of, for example, about 1% × 10% = 0.1% of the incident light to the first beam splitter 7a (the S-polarized component for the first beam splitter 7a) And a P-polarized component for the second beam splitter 7b).

  Thus, in the polarization monitor 7, the first beam splitter 7 a has a function of extracting reflected light having a polarization state different from the polarization state of incident light from the optical path according to the reflection characteristics. As a result, the output of the first light intensity detector 7c (information on the intensity of the transmitted light of the second beam splitter 7b, that is, the first beam splitter is slightly affected by the polarization fluctuation due to the polarization characteristic of the second beam splitter 7b. 7a), the polarization state (degree of polarization) of the incident light on the first beam splitter 7a, and thus the illumination light on the mask M and the wafer W. The polarization state can be detected.

  The polarization monitor 7 is set so that the P-polarized light for the first beam splitter 7a becomes S-polarized light for the second beam splitter 7b and the S-polarized light for the first beam splitter 7a becomes P-polarized light for the second beam splitter 7b. ing. As a result, based on the output of the second light intensity detector 7d (information on the intensity of light sequentially reflected by the first beam splitter 7a and the second beam splitter 7b), the polarization of the incident light to the first beam splitter 7a. The light quantity (intensity) of the incident light on the first beam splitter 7a and the light quantity of the illumination light on the mask M can be detected without being substantially affected by the change in the state.

  In this way, the polarization monitor 7 is used to detect the polarization state of the incident light on the first beam splitter 7a, and thus whether the illumination light to the mask M is in a desired non-polarized state, linearly polarized state or circularly polarized state. It can be determined whether or not. When the control unit confirms that the illumination light to the mask M (and thus the wafer W) is not in the desired non-polarized state, linearly polarized state, or circularly polarized state based on the detection result of the polarization monitor 7, The quarter-wave plate 17aa (17ba), the half-wave plate 17ab (17bb), and the depolarizer 17ac (17bc) constituting the state changing unit 17a (17b) are driven and adjusted, and the state of illumination light to the mask M is desired. Can be adjusted to a non-polarized state, a linearly polarized state, or a circularly polarized state.

  In the present embodiment, as described above, the right-angle prism 13 splits the light beam from the light source 1 into the first optical system (14a to 25a) and the second optical system (14b to 25b) and splits the wave front. Is configured. Further, in the optical path between the light source 1 and the right-angle prism 13, means for forming an illumination field having a substantially uniform illuminance distribution in the vicinity of the right-angle prism 13, that is, the illuminance distribution in the vicinity of the right-angle prism 13 is substantially uniform. As an illuminance uniformizing means for achieving this, a fly-eye lens 11 and a condenser lens 12 are disposed.

  In this way, one light beam divided by the right-angle prism 13 passes through the first optical system (14a to 25a) including the diffractive optical element 20a and the micro fly's eye lens 6, and the circular surface light source (secondary light source 40). A light intensity distribution) 40a located in the first region including the optical axis AX on the illumination pupil plane. On the other hand, the other light beam divided by the right-angle prism 13 has a second optical system (14b-25b) including the diffractive optical element 20b and a micro fly eye along an optical path different from that of the first optical system (14a-25a). A quadrupolar surface light source (light intensity distribution located in a second region away from the optical axis AX on the illumination pupil plane) 40 b of the secondary light source 40 is formed via the lens 6.

  Here, the diffractive optical element 20a (20b) is arranged in the optical path of the first optical system (second optical system), and enters the incident light beam into a circular surface light source 40a in the first region (four poles in the second region). A first light beam conversion element (second light beam conversion element) for converting into a light beam corresponding to the planar surface light source 40b). The micro fly's eye lens 6 is based on the light beam from the diffractive optical element 20a as the first light beam conversion element and the light beam from the diffractive optical element 20b as the second light beam conversion element. That is, an optical integrator for forming a secondary light source (illumination pupil distribution) 40 on the illumination pupil plane) is configured.

  Further, the diffractive optical element 20a as the first light flux conversion element, the diffractive optical element 20b as the second light flux conversion element, and the micro fly's eye lens 6 as the optical integrator are a circular surface light source (that is, on the illumination pupil plane). A secondary light source (illumination pupil distribution) 40 having a light intensity distribution 40a located in the first region 40a and a quadrupole surface light source (ie, a light intensity distribution located in the second region on the illumination pupil plane) 40b. The illumination pupil forming means for forming is configured. Further, the condenser optical system 8 and the imaging optical system 10 constitute a light guide optical system for guiding the light beam from the micro fly's eye lens 6 as an optical integrator to the mask M that is an irradiated surface.

  Further, as described above, the conical axicon system 23a as the first axicon system and the zoom lens (variable magnification optical system) 24a are arranged in the optical path of the first optical system (14a to 25a) and have a circular surface. A first shape changing means for changing the shape of the light source (first region) 40a is configured. Similarly, a conical axicon system 23b as a second axicon system and a zoom lens (magnification variable optical system) 24b are arranged in the optical path of the second optical system (14b to 25b) and are a quadrupole surface light source (first optical system). 2 area | region) The 2nd shape change means for changing the shape of 40b is comprised.

  Further, as described above, in the polarization state changing unit 17a (17b), the half-wave plate 17ab (17bb) is arranged in the optical path of the first optical system (second optical system) and is incident on linearly polarized light that is incident. A first phase member (second phase member) for changing the polarization direction as necessary is configured. In addition, the depolarizer 17ac (17bc) is configured to be detachable with respect to the optical path of the first optical system (second optical system), and the first depolarization for depolarizing incident light as necessary. An element (second depolarization element) is configured.

  The quarter-wave plate 17aa (17ba) is disposed in the optical path of the first optical system (second optical system) and constitutes a phase member for converting incident elliptically polarized light into linearly polarized light. doing. Thus, the polarization state changing unit 17a constitutes first polarization state changing means for changing the polarization state of the light beam that is arranged in the optical path of the first optical system and passes through the circular surface light source 40a in the first region. doing. On the other hand, the polarization state changing unit 17b includes second polarization state changing means for changing the polarization state of the light beam that is disposed in the optical path of the second optical system and passes through the quadrupole surface light source 40b in the second region. It is composed.

  Further, as described above, the mirror 3, the mirror driving unit 4, the fly-eye lens 11, the condenser lens 12, and the right-angle prism 13 change the light quantity division ratio in the right-angle prism 13, and are led to the first optical system. The light intensity (light quantity) of the light beam passing through the circular surface light source 40a in the first area and the light intensity (light quantity) of the light beam guided to the second optical system and passing through the quadrupole surface light source 40b in the second area. The light intensity ratio changing means for changing the ratio is configured.

  Thus, in the present embodiment, the first shape changing means having the conical axicon system 23a and the zoom lens 24a and the second shape changing means having the conical axicon system 23b and the zoom lens 24b cause the circular shape of the first region. The surface light source 40a and the shape of the second region quadrupole surface light source 40b can be controlled independently of each other. In addition, due to the action of the first polarization state changing unit having the polarization state changing unit 17a and the second polarization state changing unit having the polarization state changing unit 17b, the light flux passing through the circular surface light source 40a in the first region is changed. It is possible to perform control for independently changing the polarization state and the polarization state of the light beam passing through the quadrupolar surface light source 40b in the second region.

  In other words, the first shape changing means, the second shape changing means, the first polarization state changing means, and the second polarization state changing means change the shape of the first region and the shape of the second region independently of each other. Illumination pupil control means for performing control and control for independently changing the polarization state of the light beam passing through the first region and the polarization state of the light beam passing through the second region are configured. Further, in the present embodiment, the circular surface light source 40a in the first region is formed by the action of the light intensity ratio changing means having the mirror 3, the mirror driving unit 4, the fly-eye lens 11, the condenser lens 12, and the right-angle prism 13. Control can be performed to change the ratio of the light intensity of the light beam passing through and the light intensity of the light beam passing through the quadrupole surface light source 40b in the second region.

  As described above, in the illumination optical devices (1 to 10) of the present embodiment, appropriate illumination conditions necessary for faithfully transferring a mask pattern having various characteristics, such as the shape and light intensity of the secondary light source, Various illumination conditions can be realized with respect to the polarization state and the like. In addition, since the exposure apparatus of the present invention can realize appropriate illumination conditions necessary for faithfully transferring a mask pattern having various characteristics, appropriate illumination realized according to the pattern characteristics of the mask. Good exposure can be performed under conditions.

  In the above-described embodiment, the diffractive optical elements 20a and 20b are configured to be detachable with respect to the optical path, and are configured to be exchangeable with other diffractive optical elements having different characteristics. Therefore, instead of the diffractive optical element 20b for quadrupole illumination in the second optical system, for example, by setting a diffractive optical element for dipole illumination (for octupole illumination) in the optical path, three poles (9 poles) ) Lighting can be performed. Further, instead of the diffractive optical element 20b for quadrupole illumination in the second optical system, for example, by setting a diffractive optical element for annular illumination in the optical path, modified annular illumination can be performed.

  Further, instead of the diffractive optical element 20a for circular illumination in the first optical system, octupole illumination can be performed by setting, for example, a diffractive optical element 20b for quadrupole illumination in the optical path. Similarly, in place of the diffractive optical element 20a for circular illumination in the first optical system and the diffractive optical element 20b for quadrupole illumination in the second optical system, a diffractive optical element having appropriate characteristics is set in the optical path. By doing so, various forms of modified illumination can be performed. Further, circular illumination can be performed by retracting the diffractive optical element 20b for quadrupole illumination from the optical path, and quadrupole illumination can be performed by retracting the diffractive optical element 20a for circular illumination from the optical path.

In the above-described embodiment, one light beam divided by the right-angle prism 13 is guided to the first optical system (14a to 25a), and the other light beam divided by the right-angle prism 13 is the second optical system (14b to 14b). 25b). However, the present invention is not limited to this, and the third light beam on the illumination pupil plane is split through the third optical system along the optical path different from that of the first optical system and the second optical system. A configuration leading to the region is also possible.
For example, the surface light source 40a shown in FIG. 3 is formed in the first region on the illumination pupil plane by the first optical system (14a to 25a), and the illumination optical plane on the illumination pupil plane is formed by the second optical system (14b to 25b). The surface light sources 40b1 and 40b4 shown in FIG. 3 are formed in the second region, and a third region on the illumination pupil plane is formed by a third optical system (not shown) different from the first and second optical systems. In the configuration in which the surface light sources 40b2 and 40b3 shown in FIG. 3 are formed, the polarization state of the light beam reaching the surface light source 40a is set to non-polarized, X-direction polarized light or Z-direction polarized light, and reaches the surface light sources 40b1 and 40b4. The polarization state of the light beam is set to linearly polarized light having a polarization plane in the tangential direction of the circle around the optical axis, and the polarization state of the light beam reaching the surface light sources 40b2 and 40b3 is polarized in the tangential direction of the circle around the optical axis. Linearly polarized light with a surface (surface light source 40 The polarization direction of the light beam reaching the 1,40b4 may be set to a linearly polarized light) having a polarization plane in a direction perpendicular.

  FIG. 7 is a diagram schematically showing a configuration of a control unit according to the first modification of the present embodiment. The control unit 50 of the first modification has a configuration similar to the control unit 5 of the embodiment shown in FIG. However, in the first modification, only the configuration between the zoom lenses 24a and 24b and the micro fly's eye lens 6 is different from the embodiment of FIG. Hereinafter, the configuration and operation of the control unit 50 according to the first modification will be described with a focus on differences from the embodiment of FIG.

  Referring to FIG. 7, in the control unit 50 of the first modification, the light beam emitted from the first optical system (14a to 24a) via the zoom lens 24a is a right-angle prism (or a bending mirror) 27 as a deflecting member. Is reflected in the + Z direction. The light beam reflected in the + Z direction by the right-angle prism 27 enters a right-angle prism (or a bending mirror) 29 as a deflection member disposed on the optical axis of the second optical system via the relay lens system 28. The light beam from the first optical system reflected in the + Y direction by the right-angle prism 29 reaches the micro fly's eye lens 6 via the relay lens system 30.

  On the other hand, the light beam emitted from the second optical system (14 b to 24 b) via the zoom lens 24 b reaches the micro fly's eye lens 6 via the relay lens system 30 without being blocked by the right-angle prism 29. In the first modification, the conical axicon system 23a (23b), the reflecting surface of the right-angle prism 27, the reflecting surface of the right-angle prism 29, and the incident surface of the micro fly's eye lens 6 are optically substantially conjugate. It has become. The predetermined plane 22a (22b), the pupil plane of the relay lens system 28, the pupil plane of the relay lens system 30, and the rear focal plane (or exit plane) of the micro fly's eye lens 6 are optically almost the same. It is conjugate.

  The right-angle prisms 27 and 29 are arranged in an optical path between the right-angle prism 13 as a dividing element and the mask M as an illumination pupil plane, and the optical axis of the first optical system (14a to 24a) A combining element for combining the optical axes of the second optical systems (14b to 24b) is configured. Also in the first modified example, as in the above-described embodiment, the control for changing the shape of the circular surface light source 40a in the first region and the shape of the surface light source 40b in the second region quadrupole independently from each other, the first Control for independently changing the polarization state of the light beam passing through the circular surface light source 40a in the region and the polarization state of the light beam passing through the quadrupole surface light source 40b in the second region, and the circular shape of the first region The ratio of the light intensity of the light beam passing through the surface light source 40a to the light intensity of the light beam passing through the quadrupole surface light source 40b in the second region can be changed.

  FIG. 8 is a diagram schematically illustrating a main configuration of a control unit according to a second modification of the present embodiment. The control unit 51 of the second modification has a main part configuration similar to that of the control unit 5 of the embodiment shown in FIG. 2 and the control unit 50 of the first modification. However, in the second modification, the configuration between the mirror 3 and the polarization state changing units 17a and 17b is different from the embodiment of FIG. 2 and the first modification. Hereinafter, the configuration and operation of the control unit 51 of the second modification will be described by focusing on the differences between the embodiment of FIG. 2 and the first modification.

  Referring to FIG. 8, in the control unit 51 of the second modification, the light beam reflected in the + Y direction by the mirror 3 enters the beam splitter 31. The light beam reflected in the −Z direction by the beam splitter 31 and guided to the first optical system is reflected in the + Y direction by the bending mirror 32, and then passes through at least one neutral density filter 33a, and then the polarization state changing unit 17a. To reach. On the other hand, the light beam transmitted through the beam splitter 31 and guided to the second optical system reaches the polarization state changing unit 17b via at least one neutral density filter 33b. The configuration on the rear side (the micro fly's eye lens 6 side) from the polarization state changing units 17a and 17b is the same as that of the embodiment of FIG. 2 or the first modification.

  Here, the neutral density filter 33a and the neutral density filter 33b are configured to be insertable / removable with respect to the optical path, and are configured to be interchangeable with other neutral density filters having different characteristics. In other words, the neutral density filter 33a is at least one dimming means that can be selectively inserted into and removed from the optical path of the first optical system, and is disposed in the optical path of the first optical system so as to be circular in the first region. A first light intensity changing means for changing the light intensity of the light beam passing through the shaped surface light source 40a is configured. The neutral density filter 33b is at least one dimming means that can be selectively inserted into and removed from the optical path of the second optical system, and is disposed in the optical path of the second optical system. The second light intensity changing means for changing the light intensity of the light beam passing through the polar surface light source 40b is configured.

  Therefore, in the second modification, the mirror driving unit 4 for tilting the mirror 3 is not necessary. For example, the light split ratio in the beam splitter 31 is set to 1: 1, and the neutral density filter 33a or the neutral density filter 33b is replaced with another neutral density filter having different characteristics, or the neutral density filter 33a or the neutral density filter 33b. 2 is retracted from the optical path, unlike the embodiment of FIG. 2 or the first modification, the light intensity of the light beam passing through the circular surface light source 40a in the first region and the quadrupolar shape in the second region. It is possible to perform control for independently changing the light intensity of the light beam passing through the surface light source 40b.

  In each of the above-described embodiments or modifications, a diffractive optical element that forms a substantially uniform light intensity distribution in the far field (or Fraunhofer diffraction region) is applied in place of the fly-eye lens 11 as illuminance uniformizing means. May be. Here, the far field (or Fraunhofer diffraction region) of this diffractive optical element is relayed to or near the rear focal position of the condenser lens 12 as the illuminance uniformizing means.

  Further, in each of the above-described embodiments or modifications, from the diffractive optical element 20a (20b) to the zoom lens 24a (24b) in the first optical system (14a to 25a) and the second optical system (14b to 25b). The optical system is, for example, an optical system from the diffractive optical element 51 to the zoom lens 7 of an illumination optical device disclosed in Japanese Patent Laid-Open No. 2001-176766, or a micro of an illumination optical device disclosed in Japanese Patent Laid-Open No. 2001-85923. Optical system from lens array 4 to zoom lens 7, optical system from diffractive optical element 4 to zoom lens 7 disclosed in Japanese Patent Application Laid-Open No. 2002-231619, illumination optical device disclosed in Japanese Patent Application Laid-Open No. 2003-178951 An optical system from the diffractive optical element 4 to the zoom lens 7 of the illumination optical apparatus disclosed in Japanese Patent Laid-Open No. 2003-178952 It can be replaced from time beam forming unit 2 such as an optical system to the variable magnification optical system 4.

  In the exposure apparatus according to the above-described embodiment, the illumination optical device illuminates the mask (reticle) (illumination process), and the projection optical system is used to expose the transfer pattern formed on the mask onto the photosensitive substrate (exposure). Step), a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Refer to the flowchart of FIG. 9 for an example of a technique for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the above-described embodiment. To explain.

  First, in step 301 of FIG. 9, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot of wafers. Thereafter, in step 303, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot through the projection optical system using the exposure apparatus of the above-described embodiment. Thereafter, in step 304, the photoresist on the one lot of wafers is developed, and in step 305, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer. Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the semiconductor device manufacturing method described above, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput.

  In the exposure apparatus of the above-described embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 10, in the pattern formation process 401, a so-called photolithography process is performed in which the exposure pattern of the above-described embodiment is used to transfer and expose a mask pattern onto a photosensitive substrate (such as a glass substrate coated with a resist). . By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step 402.

  Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter forming step 402, a cell assembly step 403 is executed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like.

  In the cell assembly step 403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step 401 and the color filter obtained in the color filter formation step 402, and a liquid crystal panel (liquid crystal cell) is obtained. ). Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

In the above-described embodiment, KrF excimer laser light (wavelength: 248 nm) or ArF excimer laser light (wavelength: 193 nm) is used as the exposure light. However, the present invention is not limited to this, and other appropriate laser light sources are used. For example, the present invention can also be applied to an F ₂ laser light source that supplies laser light having a wavelength of 157 nm. Furthermore, in the above-described embodiment, the present invention has been described by taking an exposure apparatus including an illumination optical apparatus as an example. However, the present invention is applied to a general illumination optical apparatus for illuminating an irradiated surface other than a mask or a wafer. Obviously you can do that.

  In the above-described embodiment, a so-called immersion method is applied in which the optical path between the projection optical system and the photosensitive substrate is filled with a medium (typically liquid) having a refractive index larger than 1.1. You may do it. In this case, as a method of filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method of locally filling the liquid as disclosed in International Publication No. WO99 / 49504, A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Laid-Open No. 6-124873 in a liquid bath, or a predetermined depth on a stage as disclosed in Japanese Patent Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed.

As the liquid, it is preferable to use a liquid that is transmissive to exposure light and has a refractive index as high as possible, and is stable with respect to a photoresist applied to the projection optical system and the substrate surface, for example, KrF excimer laser light. When ArF excimer laser light is used as exposure light, pure water or deionized water can be used as the liquid. When F ₂ laser light is used as exposure light, a fluorine-based liquid such as fluorine oil or perfluorinated polyether (PFPE) that can transmit the F ₂ laser light may be used as the liquid.

1 is a drawing schematically showing an overall configuration of an exposure apparatus according to an embodiment of the present invention. It is a figure which shows schematically the internal structure of the control unit in FIG. It is a figure which shows schematically the pentapolar secondary light source formed in the back side focal plane of a micro fly's eye lens, or its vicinity. It is a figure explaining the effect | action of a cone axicon system with respect to the quadrupole surface light source which comprises a secondary light source. It is a figure explaining the cooperation effect | action of a cone axicon system and a zoom lens with respect to a pentapolar secondary light source. FIG. 2 is a perspective view schematically showing an internal configuration of the polarization monitor of FIG. 1. It is a figure which shows schematically the structure of the control unit concerning the 1st modification of this embodiment. It is a figure which shows roughly the principal part structure of the control unit concerning the 2nd modification of this embodiment. It is a flowchart of the method at the time of obtaining the semiconductor device as a microdevice. It is a flowchart of the method at the time of obtaining the liquid crystal display element as a microdevice.

Explanation of symbols

1 Light source 5, 50, 51 Control unit 6 Micro fly eye lens (fly eye lens)
7 Polarization Monitor 7a Beam Splitter 8 Condenser Optical System 9 Mask Blind 10 Imaging Optical System 11 Fly Eye Lens 13 Right Angle Prism (Division Element)
17 Polarization state changing unit 19 Detector 20 Diffractive optical element (light beam conversion element)
21 Afocal lens 23 Conical axicon system 24 Zoom lens 26 Condensing optical system M Mask PL Projecting optical system W Wafer

Claims (25)

In the illumination optical device that illuminates the illuminated surface with the light flux from the light source,
Illumination pupil forming means for forming an illumination pupil distribution having a light intensity distribution located in the first region on the illumination pupil plane and a light intensity distribution located in the second region;
Control for changing the shape of the first region and the shape of the second region independently of each other, and the polarization state of the light beam passing through the first region and the polarization state of the light beam passing through the second region are independent of each other. An illumination optical apparatus comprising: an illumination pupil control means for performing control to change to A splitting element for splitting a light flux from the light source;
A first optical system for guiding one light beam split through the splitting element to the first region on the illumination pupil plane;
A second optical system for guiding the other light beam split through the splitting element to the second region on the illumination pupil plane along an optical path different from that of the first optical system. The illumination optical apparatus according to claim 1, wherein 3. An illuminance equalizing unit disposed in an optical path between the light source and the dividing element and configured to substantially uniform an illuminance distribution in the vicinity of the dividing element. The illumination optical device described. 4. The illumination optical apparatus according to claim 2, wherein the splitting element guides the light flux from the light source to the first optical system and the second optical system by splitting the wavefront thereof. 5. The illumination pupil forming means includes a first light beam conversion element arranged in the optical path of the first optical system for converting an incident light beam into a light beam corresponding to the first region, and an optical path of the second optical system. A second light beam conversion element for converting an incident light beam disposed therein into a light beam corresponding to the second region, a light beam from the first light beam conversion element, and a light beam from the second light beam conversion element The illumination optical apparatus according to claim 2, further comprising an optical integrator for forming the illumination pupil distribution on the illumination pupil plane. The illumination pupil control means is arranged in the optical path of the first optical system and is arranged in the optical path of the second optical system, and first shape changing means for changing the shape of the first region. 6. The illumination optical apparatus according to claim 2, further comprising a second shape changing unit for changing the shape of the second region. The first shape changing means has a first axicon system disposed in an optical path between the first light flux conversion element and the optical integrator,
The second shape changing means has a second axicon system disposed in an optical path between the second light flux conversion element and the optical integrator,
The first axicon system and the second axicon system include a first prism having a concave sectional refractive surface, and a convex sectional refractive surface formed substantially complementary to the concave sectional refractive surface of the first prism. The illumination optical device according to claim 6, wherein each of the second prisms includes a second prism, and an interval between the first prism and the second prism is variable. The first shape changing means has a first variable magnification optical system disposed in an optical path between the first light flux conversion element and the optical integrator,
8. The illumination optical apparatus according to claim 7, wherein the second shape changing unit includes a second variable magnification optical system disposed in an optical path between the second light beam conversion element and the optical integrator. . The illumination pupil control means includes first polarization state changing means for changing the polarization state of a light beam that is disposed in the optical path of the first optical system and passes through the first region, and an optical path of the second optical system. The illumination optics according to any one of claims 2 to 8, further comprising second polarization state changing means for changing a polarization state of a light beam that is disposed inside and passes through the second region. apparatus. The first polarization state changing means has a first phase member arranged in the optical path of the first optical system for changing the polarization direction of the linearly polarized light that is incident as necessary.
The second polarization state changing means includes a second phase member arranged in the optical path of the second optical system and configured to change the polarization direction of incident linearly polarized light as necessary. 9. The illumination optical apparatus according to 9. The first polarization state changing unit includes a first depolarizing element configured to be detachable with respect to the optical path of the first optical system and depolarizing incident light as necessary.
The second polarization state changing means includes a second depolarizing element configured to be detachable with respect to the optical path of the second optical system and depolarizing incident light as necessary. The illumination optical apparatus according to claim 9 or 10, characterized in that The illumination pupil forming means includes a first light beam conversion element arranged in the optical path of the first optical system for converting an incident light beam into a light beam corresponding to the first region, and an optical path of the second optical system. A second light beam conversion element for converting the incident light beam disposed therein into a light beam corresponding to the second region,
The first polarization state changing means is arranged in an optical path between the splitting element and the first light beam conversion element, and a first phase member for changing the polarization direction of the linearly polarized light that is incident as necessary. A first depolarizing element that is detachably disposed in the optical path between the splitting element and the first light flux converting element and depolarizes incident light as necessary.
The second polarization state changing means is disposed in the optical path between the splitting element and the second light beam conversion element, and a second phase member for changing the polarization direction of the linearly polarized light that is incident as necessary, And a second depolarizing element that is detachably disposed in the optical path between the splitting element and the first light flux converting element and depolarizes incident light as necessary. The illumination optical apparatus according to claim 9, wherein the illumination optical apparatus is an illumination optical apparatus. The illumination pupil control means includes first light intensity changing means for changing the light intensity of the light beam passing through the first area, and second light for changing the light intensity of the light flux passing through the second area. The illumination optical apparatus according to claim 2, further comprising an intensity changing unit. The first light intensity changing means is disposed in an optical path of the first optical system, and the second light intensity changing means is disposed in an optical path of the second optical system. The illumination optical device described. The first light intensity changing means has at least one dimming means that can be selectively inserted into and removed from the optical path of the first optical system, and the second light intensity changing means is an optical path of the second optical system. 15. The illumination optical apparatus according to claim 14, further comprising at least one dimming means that can be selectively inserted into and removed from the light. 16. The illumination optical apparatus according to claim 3, wherein the first light beam conversion element and the second light beam conversion element are configured to be interchangeable with respect to an optical path. 17. The first area according to claim 1, wherein the first area is an area including an optical axis on the illumination pupil plane, and the second area is an area away from the optical axis on the illumination pupil plane. The illumination optical device according to any one of the above. The illumination optical apparatus according to claim 17, wherein the second region has an annular shape or a multipolar shape. The illumination optical apparatus according to claim 3, further comprising a light guide optical system for guiding a light beam from the optical integrator to the irradiated surface. In the illumination optical device that illuminates the illuminated surface with the light flux from the light source,
Illumination pupil forming means for forming an illumination pupil distribution having a light intensity distribution located in the first region on the illumination pupil plane and a light intensity distribution located in the second region;
The illumination pupil forming means includes
A splitting element disposed in an optical path between the light source and the illumination pupil plane;
A first optical system for guiding one light beam divided through the dividing element to a first region on the illumination pupil plane;
A second optical system for guiding the other light beam split through the splitting element to a second region on the illumination pupil plane along an optical path different from that of the first optical system;
A combining element disposed in an optical path between the dividing element and the illumination pupil plane for combining the optical axis of the first optical system and the optical axis of the second optical system;
The first optical system includes a first light beam conversion element for converting an incident light beam into a light beam corresponding to the first region,
The illumination optical apparatus, wherein the second optical system includes a second light beam conversion element for converting an incident light beam into a light beam corresponding to the second region. The illumination pupil forming means guides a light beam split through the splitting element to a third region on the illumination pupil plane along an optical path different from that of the first optical system and the second optical system. The illumination optical apparatus according to any one of claims 2 to 20, further comprising three optical systems. An exposure apparatus comprising the illumination optical apparatus according to any one of claims 1 to 21 for illuminating a mask and exposing a pattern of the mask onto a photosensitive substrate. A projection optical system for forming an image of the mask pattern on the photosensitive substrate;
23. The exposure apparatus according to claim 22, wherein a pupil plane of the illumination optical apparatus is positioned substantially conjugate with a pupil position of the projection optical system. An illumination step of illuminating the mask using the illumination optical apparatus according to any one of claims 1 to 21,
And an exposure step of exposing the pattern of the mask onto a photosensitive substrate. The exposure step includes a projection step of forming an image of the mask pattern on the photosensitive substrate using a projection optical system,
25. The exposure method according to claim 24, wherein a pupil plane of the illumination optical device is positioned substantially conjugate with a pupil position of the projection optical system.

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