JP2010283100A - Polarization conversion unit, illumination optical system, exposure device, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarization conversion unit that can convert incident light into a desired polarized light and project it even when the light is incident in a polarization state changed from a necessary polarization state under an influence of an optical element arranged, for example, on the front side. <P>SOLUTION: The polarization conversion unit (13) which changes the polarization state of the incident luminous flux to the prescribed polarization state includes: a polarization conversion element (13b) which is formed of a birefringent crystal material and changes the polarization state of the incident light; and a polarizer (13a) which is disposed on the incident side or the polarization side of the polarization conversion element, selects light in the predetermined polarization state from the incident light, and projects it. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polarization conversion unit, an illumination optical system, an exposure apparatus, and a device manufacturing method. More specifically, the present invention relates to an illumination optical system suitable for an exposure apparatus for manufacturing a device such as a semiconductor element, an imaging element, a liquid crystal display element, and a thin film magnetic head in a lithography process.

  In a typical exposure apparatus of this type, light emitted from a light source forms a secondary light source as a substantial surface light source including a large number of light sources via a fly-eye lens as an optical integrator. The light from the secondary light source (generally, the light intensity distribution formed in or near the illumination pupil of the illumination optical system, that is, the pupil intensity distribution) is condensed by the condenser optical system, and then a predetermined pattern is formed. Illuminate the mask in a superimposed manner. The light transmitted through the mask forms an image on a wafer (photosensitive substrate) via a projection optical system, and a mask pattern is projected and exposed (transferred) onto the wafer. The pattern formed on the mask is highly integrated, and it is indispensable to obtain a uniform illumination distribution on the wafer in order to accurately transfer the fine pattern onto the wafer.

  In recent years, in order to realize an illumination condition suitable for faithfully transferring a fine pattern in an arbitrary direction, for example, an annular or multipolar (bipolar) is formed on the rear focal plane of a fly-eye lens or an illumination pupil in the vicinity thereof. A quadrupolar secondary light source (annular or multipolar pupil intensity distribution), and a light beam passing through the secondary light source has a linear polarization state (hereinafter, referred to as a polarization direction). There has been proposed a technique for setting so as to be referred to as “circumferential polarization state” (see, for example, Patent Document 1). In this technique, after a linear polarization state is generated using a wave plate, a circumferential polarization state is generated using a polarization conversion element including a plurality of optical rotation members.

International Publication No. 2005/076045 Pamphlet

  In the prior art described in Patent Document 1, a desired circumferential polarization state is generated immediately after the polarization conversion element by the cooperative action of the wavelength conversion plate and the polarization conversion element disposed relatively upstream of the illumination optical system. Is done. However, due to the influence of an optical element that is arranged in the optical path downstream of the polarization conversion element and changes the polarization state of light, light does not form an image in a desired circumferential polarization state on the photosensitive substrate, and as a result, a mask It is difficult to form the pattern image on the photosensitive substrate with a required contrast.

  In this case, a configuration is also possible in which the polarization conversion element is arranged as downstream as possible from the illumination optical system, and the mask (and thus the wafer) is illuminated in a polarization state close to a desired polarization state generated immediately after the polarization conversion element. However, in this configuration, the linearly polarized light generated using the wave plate changes from the desired linear polarization state due to the influence of the optical element disposed in the optical path between the wave plate and the polarization conversion element. Therefore, it is difficult to generate a desired circumferential polarization state immediately after the polarization conversion element.

  The present invention has been made in view of the above-described problems. For example, even when light having a polarization state changed from a required polarization state by the influence of an optical element arranged on the front side is incident, the incident light is converted into a desired polarization state. An object of the present invention is to provide a polarization conversion unit that can be converted into a state and emitted. In addition, the present invention uses a polarization conversion unit that converts incident light into a desired polarization state and emits it even when light having a polarization state changed from a required polarization state is incident. An object of the present invention is to provide an illumination optical system capable of illuminating an irradiation surface. The present invention also provides an exposure apparatus that can form an image of a pattern on a photosensitive substrate in a desired polarization state using an illumination optical system that illuminates the pattern on the irradiated surface with light in the desired polarization state. The purpose is to do.

In order to solve the above-mentioned problem, in the first embodiment of the present invention, in the polarization conversion unit that converts the polarization state of the incident light beam into a predetermined polarization state and emits it,
A polarization conversion element that is formed of a birefringent crystal material and changes a polarization state of incident light;
There is provided a polarization conversion unit comprising: a polarizer that is disposed on an incident side or an emission side of the polarization conversion element, and that selects and emits light having a specific polarization state from incident light.

In the second embodiment of the present invention, in the illumination optical system that illuminates the illuminated surface with the light from the light source,
Provided is an illumination optical system comprising a first type of polarization conversion unit disposed in an optical path between the light source and the irradiated surface.

  According to a third aspect of the present invention, in an illumination optical system that illuminates a surface to be irradiated with light from a light source, at least one optical path bending mirror that deflects the traveling direction of light from the light source, and the at least one optical path bending mirror. An illumination optical system comprising: an optical path bending mirror disposed closest to the irradiated surface; and a polarizer disposed in an optical path between the irradiated surface. According to a fourth aspect of the present invention, there is provided an exposure apparatus comprising the illumination optical system according to the second or third aspect for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. To do.

In the fifth embodiment of the present invention, using the exposure apparatus of the fourth embodiment, an exposure step of exposing the predetermined pattern to the photosensitive substrate;
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

  In the polarization conversion unit according to one aspect of the present invention, a polarizer is disposed adjacent to the incident side of the polarization conversion element. Therefore, for example, even when light having a polarization state changed from a required polarization state is incident on the polarization conversion unit due to the influence of an optical element arranged on the front side and changing the polarization state of light, the polarizer changes the polarization state of the incident light. The light is returned to the required polarization state (strictly close to the required polarization state) and is incident on the polarization conversion element. The polarization conversion element changes the polarization state of the incident light in a required polarization state and emits it after changing it to a desired polarization state.

  As described above, in the polarization conversion unit according to the above-described aspect, even when light having a polarization state changed from a required polarization state due to the influence of the optical element disposed on the front side is incident, the incident light is changed to a desired polarization state. Can be converted and injected. The illumination optical system of the present invention uses a polarization conversion unit that converts the incident light into a desired polarization state and emits it even when light having a polarization state changed from the required polarization state is incident, and the desired polarization state. The illuminated surface can be illuminated with the light of. Further, in the exposure apparatus of the present invention, the illumination optical system that illuminates the pattern of the irradiated surface with light having a desired polarization state can image the pattern on the photosensitive substrate in a desired polarization state, As a result, a favorable device can be manufactured.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows schematically the structure of the polarization conversion element of FIG. It is a figure which shows roughly the cross-shaped quadrupole secondary light source set to the circumferential polarization state. It is a figure explaining the optical rotatory power of quartz. It is a figure which shows roughly the cross-shaped quadrupole secondary light source set to the radial direction polarization | polarized-light state. It is a figure which shows roughly the X-shaped quadrupole secondary light source set to the circumferential polarization state. It is a figure which shows roughly the X-shaped quadrupole secondary light source set to the radial polarization state. It is a figure which shows roughly the structure of the polarization conversion element concerning a modification. It is a figure which shows schematically the structure of the polarizer using a Brewster angle. It is a figure which shows roughly the structure of the polarization conversion unit concerning a modification. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the Z axis along the normal direction of the transfer surface of the wafer W, which is a photosensitive substrate, the Y axis in the direction parallel to the paper surface of FIG. The X axis is set in the direction perpendicular to the paper surface of FIG. Referring to FIG. 1, in the exposure apparatus of the present embodiment, exposure light (illumination light) is supplied from a light source 1.

  As the light source 1, for example, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. The light beam emitted from the light source 1 enters the afocal lens 5 via the shaping optical system 2, the optical path bending mirror PM 1, the polarization state switching system 3, and the diffractive optical element 4. The shaping optical system 2 has a function of converting a substantially parallel light beam from the light source 1 into a light beam having a predetermined rectangular cross section and guiding it to the polarization state switching system 3.

  The polarization state switching system 3 includes, in order from the light source side, a quarter-wave plate 3a that converts incident elliptically polarized light into linearly polarized light, with the crystal optical axis being rotatable about the optical axis AX, A half-wave plate 3b that changes the polarization direction of linearly polarized light that is incident on the optical axis AX so that the crystal optical axis is rotatable, and a depolarizer that can be inserted into and removed from the illumination optical path (depolarizing element). 3c. The polarization state switching system 3 has a function of converting the light from the light source 1 into linearly polarized light having a desired polarization direction and making it incident on the diffractive optical element 4 with the depolarizer 3c retracted from the illumination optical path.

  The polarization state switching system 3 has a function of converting the light from the light source 1 into substantially non-polarized light and making it incident on the diffractive optical element 4 in a state where the depolarizer 3c is set in the illumination optical path. The afocal lens 5 includes a front lens group 5a and a rear lens group 5b. The front focal position of the front lens group 5a and the position of the diffractive optical element 4 substantially coincide with each other, and the rear focal position of the rear lens group 5b. And an afocal system (non-focal optical system) set so that the position of the predetermined surface 6 indicated by a broken line in FIG.

  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. The diffractive optical element 4 is detachable with respect to the illumination optical path, and is configured to be switchable with other diffractive optical elements having different characteristics. Hereinafter, in order to facilitate understanding of the description, it is assumed that a diffractive optical element for quadrupole illumination is arranged in the illumination optical path.

  The diffractive optical element 4 for quadrupole illumination has a function of forming a quadrupole light intensity distribution in the far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. Accordingly, the substantially parallel light beam incident on the diffractive optical element 4 forms a quadrupole light intensity distribution on the pupil plane of the afocal lens 5 and then exits from the afocal lens 5 as a substantially parallel light beam. A conical axicon system 7 is disposed on or near the pupil plane of the afocal lens 5. The configuration and operation of the conical axicon system 7 will be described later.

  The light passing through the afocal lens 5 passes through a zoom lens 8 for varying a σ value (σ value = mask-side numerical aperture of the illumination optical system / mask-side numerical aperture of the projection optical system), and is a micro fly as an optical integrator. The light enters the eye lens (or fly eye lens) 9. The micro fly's eye lens 9 is an optical element composed of a large number of microlenses having positive refractive power arranged vertically and horizontally and densely. 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. For example, a cylindrical micro fly's eye lens can be used as the micro fly's eye lens 9. The configuration and action of the cylindrical micro fly's eye lens are disclosed in, for example, US Pat. No. 6,913,373.

  The position of the predetermined surface 6 is disposed in the vicinity of the front focal position of the zoom lens 8, and the incident surface of the micro fly's eye lens 9 is disposed in the vicinity of the rear focal position of the zoom lens 8. In other words, the zoom lens 8 arranges the predetermined surface 6 and the incident surface of the micro fly's eye lens 9 substantially in a Fourier transform relationship, and consequently the pupil surface of the afocal lens 5 and the incident surface of the micro fly's eye lens 9. Are arranged almost conjugate optically.

  Therefore, a quadrupole illumination field centered on the optical axis AX, for example, is formed on the incident surface of the micro fly's eye lens 9 as in the pupil surface of the afocal lens 5. The overall shape of this quadrupole illumination field changes in a similar manner depending on the focal length of the zoom lens 8. The light beam incident on the micro fly's eye lens 9 is two-dimensionally divided by a large number of microlenses, and the illumination pupil formed by the incident light beam has substantially the same light intensity distribution on the rear focal plane or in the vicinity of the illumination pupil. A quadrupolar secondary light source (pupil intensity distribution) composed of secondary light sources having, for example, four circular substantially surface light sources centered on the optical axis AX is formed.

  On the rear focal plane of the micro fly's eye lens 9 or in the vicinity thereof, an illumination aperture stop having a quadrupole opening (light transmission portion) corresponding to a quadrupole secondary light source is disposed as necessary. ing. The illumination aperture stop is configured to be detachable with respect to the illumination optical path, and is configured to be switchable with a plurality of aperture stops having apertures having different sizes and shapes. As an aperture stop switching method, for example, a well-known turret method or slide method can be used. The illumination aperture stop is disposed at a position substantially optically conjugate with the entrance pupil plane of the projection optical system PL, and defines a range that contributes to illumination of the secondary light source.

  The light that has passed through the micro fly's eye lens 9 illuminates the mask blind 11 in a superimposed manner via the condenser optical system 10. In this manner, a rectangular illumination field corresponding to the shape and focal length of the micro fly's eye lens 8 is formed on the mask blind 11 as an illumination field stop. The light that has passed through the rectangular opening (light transmitting portion) of the mask blind 11 is condensed by the imaging optical system 12 including the front lens group 12a and the rear lens group 12b, and a mask in which a predetermined pattern is formed. Illuminate M in a superimposed manner.

  That is, the imaging optical system 12 forms an image of the rectangular opening of the mask blind 11 on the mask M. A polarization conversion unit 13 is disposed on or near the pupil plane of the imaging optical system 12, and an optical path bending mirror PM2 is disposed in the optical path between the front lens group 12a of the imaging optical system 12 and the polarization conversion unit 13. Has been. The pupil plane of the imaging optical system 12 is another illumination pupil plane that is optically conjugate with the rear focal plane of the micro fly's eye lens 9 or the illumination pupil plane in the vicinity thereof, and the pupil of the imaging optical system 12. A quadrupole pupil intensity distribution is also formed on the illumination pupil plane in the vicinity of the plane. The configuration and operation of the polarization conversion unit 13 will be described later.

  A pattern to be transferred is formed on the mask M held on the mask stage MS. The light transmitted through the pattern of the mask M forms an image of the mask pattern on the wafer (photosensitive substrate) W held on the wafer stage WS via 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.

  The conical axicon system 7 includes, in order from the light source side, a first prism member 7a having a flat surface facing the light source side and a concave conical refractive surface facing the mask side, and a convex conical shape facing the plane toward the mask side and the light source side. And a second prism member 7b facing the refractive surface. The concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are complementarily formed so as to be in contact with each other. Further, at least one of the first prism member 7a and the second prism member 7b is configured to be movable along the optical axis AX, and the interval between the first prism member 7a and the second prism member 7b is configured to be variable. Has been. Hereinafter, in order to facilitate understanding, the operation of the conical axicon system 7 and the operation of the zoom lens 8 will be described by focusing on the annular or quadrupolar secondary light source.

  Here, in a state where the concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are in contact with each other, the conical axicon system 7 functions and is formed as a parallel plane plate. There is no effect on the secondary or quadrupolar secondary light source. However, if the concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are separated from each other, the width of the annular or quadrupolar secondary light source (the annular secondary light source) 1/2 of the difference between the outer diameter and the inner diameter of the light source; 1/2 of the difference between the diameter (outer diameter) of the circle circumscribing the quadrupole secondary light source and the diameter (inner diameter) of the inscribed circle While maintaining, the outer diameter (inner diameter) of the annular or quadrupolar secondary light source changes. That is, the annular ratio (inner diameter / outer diameter) and size (outer diameter) of the annular or quadrupolar secondary light source change.

  The zoom lens 8 has a function of similarly enlarging or reducing the entire shape of the annular or quadrupolar secondary light source. For example, by enlarging the focal length of the zoom lens 8 from a minimum value to a predetermined value, the entire shape of the annular or quadrupolar secondary light source is similarly enlarged. In other words, due to the action of the zoom lens 8, both the width and size (outer diameter) change without changing the annular ratio of the annular or quadrupolar secondary light source. In this way, the annular ratio and size (outer diameter) of the annular or quadrupolar secondary light source can be controlled by the action of the conical axicon system 7 and the zoom lens 8.

  In the present embodiment, as described above, the secondary light source formed by the micro fly's eye lens 9 is used as a light source, and the mask M arranged on the irradiated surface of the illumination optical system (2-13) is Koehler illuminated. For this reason, the position where the secondary light source is formed is optically conjugate with the position of the aperture stop AS of the projection optical system PL, and the formation surface of the secondary light source is the illumination pupil plane of the illumination optical system (2-13). Can be called. Typically, the irradiated surface (the surface on which the mask M is disposed or the surface on which the wafer W is disposed when the illumination optical system including the projection optical system PL is considered) is optical with respect to the illumination pupil plane. A Fourier transform plane.

  The pupil intensity distribution is a light intensity distribution (luminance distribution) on the illumination pupil plane of the illumination optical system (2-13) or a plane optically conjugate with the illumination pupil plane. When the number of wavefront divisions by the micro fly's eye lens 9 is relatively large, the overall light intensity distribution formed on the incident surface of the micro fly's eye lens 9 and the overall light intensity distribution (pupil intensity distribution) of the entire secondary light source. ) And a high correlation. For this reason, the light intensity distribution on the incident surface of the micro fly's eye lens 9 and a surface optically conjugate with the incident surface can also be referred to as a pupil intensity distribution.

  In place of the diffractive optical element for quadrupole illumination, a diffractive optical element for other multipole illumination (bipolar illumination, octupole illumination, etc.) is set in the illumination optical path, so that multipole illumination other than quadrupole illumination It can be performed. In general, a diffractive optical element for multipole illumination has a light intensity distribution of multiple poles (bipolar, quadrupole, octupole, etc.) in the far field when a parallel light beam having a rectangular cross section is incident. It has the function to form. Accordingly, the light beam that has passed through the diffractive optical element for multipole illumination is incident on the incident surface of the micro fly's eye lens 9 from, for example, an illumination field having a plurality of predetermined shapes (arc shape, circular shape, etc.) centered on the optical axis AX. To form a multipolar illuminator. As a result, a secondary light source having the same multipolar shape as the illumination field formed on the incident surface is also formed on or near the rear focal plane of the micro fly's eye lens 9.

  Further, instead of the diffractive optical element for quadrupole illumination, annular illumination can be performed by setting a diffractive optical element for annular illumination in the illumination optical path. The diffractive optical element for annular illumination has a function of forming an annular light intensity distribution in the far field when a parallel light beam having a rectangular cross section is incident. Accordingly, the light flux that has passed through the diffractive optical element for annular illumination forms an annular illumination field centered on the optical axis AX, for example, on the incident surface of the micro fly's eye lens 9. As a result, a secondary light source having the same annular zone as the illumination field formed on the incident surface is also formed on or near the rear focal plane of the micro fly's eye lens 9.

  Moreover, instead of the diffractive optical element for quadrupole illumination, a normal circular illumination can be performed by setting a diffractive optical element for circular illumination in the illumination optical path. The diffractive optical element for circular illumination has a function of forming a circular light intensity distribution in the far field when a parallel light beam having a rectangular cross section is incident. Therefore, the light beam that has passed through the diffractive optical element for circular illumination forms, for example, a circular illumination field around the optical axis AX on the incident surface of the micro fly's eye lens 9. As a result, a secondary light source having the same circular shape as the illumination field formed on the incident surface is also formed on or near the rear focal plane of the micro fly's eye lens 9. In addition to the diffractive optical element for quadrupole illumination, various forms of modified illumination can be performed by setting a diffractive optical element having appropriate characteristics in the illumination optical path. As a switching method of the diffractive optical element, for example, a known turret method or slide method can be used.

  The polarization conversion unit 13 includes a polarizer 13a disposed in the optical path between the optical path bending mirror PM2 and the rear lens group 12b of the imaging optical system 12, and a polarization conversion element 13b disposed adjacent to the rear side. And. As the polarizer 13a, for example, a wire grid type polarizer can be used. Wire grid polarizers are thin metal wires arranged in parallel, transmitting polarized light with an electric vector that oscillates perpendicular to the metal wire and reflecting polarized light with an electric vector that oscillates parallel to the metal. By doing so, linearly polarized light is obtained. As such a wire grid type polarizer, for example, US Pat. No. 6,785,050, US Pat. No. 7,268,946, JP-A-2004-144484, US Pat. It is disclosed in, for example, 2004/0174596.

  FIG. 2 is a diagram schematically showing the configuration of the polarization conversion element of FIG. As described above, the polarization conversion element 13b is disposed on or near the pupil plane of the imaging optical system 12. Therefore, when the diffractive optical element 4 for quadrupole illumination is disposed in the illumination optical path, a light beam having a quadrupole cross section enters the polarization conversion element 13b. Hereinafter, as shown in FIG. 3, the pupil plane of the imaging optical system 12 or the illumination pupil in the vicinity thereof has four poles composed of substantially circular surface light sources 31A and 31B with the optical axis AX as the center. A secondary light source 31 is formed. Further, in order to facilitate understanding of the explanation, it is assumed that the quadrupolar secondary light source 31 is generated immediately after the polarization conversion element 13b.

  In the quadrupole secondary light source 31, the pair of surface light sources 31A face the Y direction (corresponding to the Z direction on the rear focal plane of the micro fly's eye lens 9 or the illumination pupil near it) across the optical axis AX. The pair of surface light sources 31B are opposed to the X direction (corresponding to the X direction on the rear focal plane of the micro fly's eye lens 9 or the illumination pupil in the vicinity thereof) across the optical axis AX. That is, FIG. 3 shows a so-called cruciform quadrupolar secondary light source 31.

  Referring to FIG. 2, the polarization conversion element 13b includes four fan-shaped optical rotation members that are equally divided in the circumferential direction of a circle around the optical axis AX so as to correspond to a cross-shaped quadrupole incident light beam. I have. Each optical rotation member has a form of a plane parallel plate extending along a plane (XY plane) orthogonal to the optical axis AX, and a pair of optical rotation members facing each other across the optical axis AX have the same characteristics. That is, the four optical rotation members include two types of optical rotation members 21A and 21B each having a different thickness (length in the optical axis direction) along the light transmission direction (Z direction).

  As an example, the thickness DB of the pair of optical rotation members 21B facing in the X direction across the optical axis AX is set larger than the thickness DA of the pair of optical rotation members 21A facing in the Y direction across the optical axis AX. ing. As a result, one surface (for example, the incident surface) of the polarization conversion element 13b is planar, but the other surface (for example, the exit surface) is uneven due to the difference in thickness of each optical rotation member. In addition, both surfaces (incident surface and exit surface) of the polarization conversion element 13b can be formed in an uneven shape.

  The optical rotatory members 21A and 21B are made of crystal as a crystal material that is an optical material having optical activity, and are set so that the crystal optical axis thereof substantially coincides with the optical axis AX (that is, substantially coincides with the traveling direction of incident light). Has been. Hereinafter, with reference to FIG. 4, the optical rotation of the crystal will be briefly described. Referring to FIG. 4, a parallel flat plate-like optical member 100 made of quartz having a thickness d is arranged so that the crystal optical axis thereof coincides with the optical axis AX. In this case, due to the optical rotation of the optical member 100, the incident linearly polarized light is emitted in a state where the polarization direction is rotated by θ around the optical axis AX.

At this time, the rotation angle (optical rotation angle) θ in the polarization direction due to the optical rotation of the optical member 100 is expressed by the following formula (a) by the thickness d of the optical member 100 and the optical rotation ρ of the crystal. In general, the optical rotation ρ of quartz has a wavelength dependency (a property in which the value of optical rotation varies depending on the wavelength of the light used: optical rotation dispersion), and specifically, it tends to increase as the wavelength of the light used decreases. is there. According to the description on page 167 of “Applied Optics II”, the optical rotation power ρ of quartz with respect to light having a wavelength of 250.3 nm is 153.9 degrees / mm.
θ = d · ρ (a)

  The optical rotatory member 21A rotates the Y direction by 90 degrees around the Z axis when light of Y direction linearly polarized light having a polarization direction in the Y direction (corresponding to Z direction linearly polarized light immediately after the polarization state switching system 3) is incident. The thickness DA is set so as to emit X-direction linearly polarized light having a polarization direction in the X direction. Therefore, when light of Y-direction linearly polarized light is incident on the polarization conversion element 13b, a light beam subjected to the optical rotation action of the pair of optical rotation members 21A is formed in the quadrupolar secondary light source 31, as shown in FIG. The polarization direction of the light beam passing through the pair of circular regions 31A is the X direction.

  On the other hand, the optical rotation member 21B emits Y-direction linearly polarized light having the polarization direction in the Y direction, that is, the Y direction rotated by 180 degrees around the Z axis when Y-direction linearly polarized light is incident. A thickness DB is set. Therefore, when light of Y-direction linearly polarized light enters the polarization conversion element 13b, as shown in FIG. 3, the light beam that passes through the pair of circular regions 31B formed by the light beam subjected to the optical rotation action of the pair of optical rotation members 21B. The polarization direction is Y direction.

  In the configuration of FIG. 1, in the case of circumferentially polarized quadrupole illumination as shown in FIG. 3 (modified illumination in which a light beam passing through a quadrupole secondary light source is set in a circumferentially polarized state), The wavelength in the polarization state switching system 3 is set so that the diffractive optical element 4 is placed in the illumination optical path and the Z-direction linearly polarized light is emitted (so that the Y-direction linearly polarized light is incident on the polarization conversion element 13b). The plates 3a and 3b are set to a required posture. As a result, a cruciform quadrupolar secondary light source (pupil intensity distribution) 31 is formed on the pupil plane of the imaging optical system 12 or in the vicinity of the illumination pupil, and passes through the quadrupolar secondary light source 31. The light beam is set to the circumferential polarization state. In the circumferential polarization state, the light beams passing through the circular regions 31A and 31B constituting the quadrupolar secondary light source 31 are circles passing through the center points of the circular regions 31A and 31B with the optical axis AX as the center. A linear polarization state having a polarization direction substantially coincident with the tangential direction at the center point is obtained.

  In general, in circumferential polarization illumination based on a multipolar or annular pupil intensity distribution in the circumferential polarization state, the light irradiated on the wafer W as the final irradiated surface is a polarization state whose main component is S polarization. become. Here, the S-polarized light is linearly polarized light having a polarization direction in a direction perpendicular to the incident surface (polarized light having an electric vector oscillating in a direction perpendicular to the incident surface). However, the incident surface is defined as a surface including the normal of the boundary surface at that point and the incident direction of light when the light reaches the boundary surface of the medium (surface to be irradiated: the surface of the wafer W). The As a result, in the circumferential polarization illumination, the optical performance (such as depth of focus) of the projection optical system can be improved, and a mask pattern image with high contrast can be obtained on the wafer (photosensitive substrate).

  In the configuration of FIG. 1, when there is no optical element that changes the polarization state of light in the optical path between the polarization state switching system 3 and the polarization conversion element 13b, the polarization state disposed on the relatively upstream side of the illumination optical system. Due to the cooperative action of the wave plates 3a and 3b in the switching system 3 and the polarization conversion element 13b disposed at or near the illumination pupil on the most downstream side of the illumination optical system, a desired circumference immediately after the polarization conversion element 13b. A directional polarization state is generated. However, in practice, a desired circumferential direction immediately after the polarization conversion element 13b due to the influence of an optical element arranged in the optical path between the polarization state switching system 3 and the polarization conversion element 13b to change the polarization state of the light. No polarization state is generated. As a result, light no longer forms an image in a desired circumferential polarization state on the wafer W, and as a result, it is difficult to form a pattern image of the mask M on the wafer W with a required contrast.

  In particular, in a plane reflecting mirror (for example, the optical path bending mirror PM2) disposed in the optical path between the polarization state switching system 3 and the polarization conversion element 13b, the angle range of incident light is wide, and S-polarized light and P with respect to the reflecting surface are obtained. The reflectivity is relatively different from that of polarized light, and the difference in reflectivity is likely to vary. For this reason, in the configuration in which the polarizer 13a is not provided, even if the polarization state switching system 3 is used to generate light in a required linear polarization state (Z-direction linear polarization state in the above example), the optical path bending mirror PM2 The light incident on the polarization conversion element 13b via the optical element such as the above becomes a polarization state changed from a required linear polarization state (for example, a polarization state in which linear polarization components other than the required linear polarization component are mixed). When light in a polarization state changed from a required linear polarization state enters the polarization conversion element 13b, a desired circumferential polarization state is not generated immediately after the polarization conversion element 13b.

  In the present embodiment, a polarizer 13a that selects and emits light in a specific linear polarization state from incident light is attached to the incident side of the polarization conversion element 13b, and the polarization conversion unit 13 includes the polarizer 13a and the polarization conversion element 13b. Is configured. In the above example, the polarizer 13a is set in the optical path so as to select and emit light in the Y-direction linearly polarized state from the incident light. Accordingly, the light in the polarization state changed from the required linearly polarized state in the Y direction is affected by the optical element that is arranged in the optical path between the polarization state switching system 3 and the polarization conversion unit 13 and changes the polarization state of the light. Even when the light is incident on the polarization conversion unit 13, the polarizer 13a returns the polarization state of the incident light to the required Y-direction linear polarization state (strictly close to the required Y-direction linear polarization state), and enters the polarization conversion element 13b. Make it incident.

  The polarization conversion element 13b changes the polarization state of the incident light in the required Y-direction linear polarization state to the desired circumferential polarization state and emits it. As described above, the polarization conversion unit 13 is not affected by the light in the polarization state changed from the required Y-direction linear polarization state due to the influence of the optical element arranged in the optical path between the polarization state switching system 3 and the polarization state switching system 3. The incident light can be converted into a desired circumferential polarization state and emitted. As a result, a light intensity distribution having a desired circumferential polarization state is generated immediately after the polarization conversion unit 13, that is, at the illumination pupil on the most downstream side in the optical path of the illumination optical system (2-13) or in the vicinity thereof.

  In the illumination optical system (2 to 13) of the present embodiment, even when light in a polarization state changed from a required Y-direction linear polarization state is incident, the incident light is converted into a desired circumferential polarization state and emitted. The conversion unit 13 can be used to illuminate the pattern surface (irradiated surface) of the mask M with light in a desired circumferential polarization state. In the exposure apparatus (2 to WS) of the present embodiment, the illumination optical system (2 to 13) that illuminates the pattern of the mask M with the light in the desired circumferential polarization state is used in the desired circumferential polarization state. The pattern can be imaged on the wafer W, and thus the pattern image of the mask M can be formed on the wafer W with a required contrast.

  In the above-described embodiment, the wave plates 3a and 3b in the polarization state switching system 3 are configured to emit X-direction linearly polarized light (so that X-direction linearly polarized light is incident on the polarization conversion element 13b). By changing the posture and switching the posture of the polarizer 13a from the first posture for selecting and emitting the Y-direction linearly polarized light to the second posture for selecting and emitting the X-direction linearly polarized light, FIG. As shown in FIG. 4, it is possible to realize modified illumination in which the light beam passing through the cross-shaped quadrupole secondary light source 32 is set in the radially polarized state, that is, radially polarized quadrupole illumination. The second posture of the polarizer 13a is obtained by rotating the polarizer 13a from the first posture by 90 degrees around the optical axis AX.

  In the radial polarization state, the light beams passing through the circular regions 32A and 32B constituting the quadrupolar secondary light source 32 are circles passing through the center points of the circular regions 32A and 32B with the optical axis AX as the center. A linear polarization state having a polarization direction in a radial direction substantially orthogonal to the tangential direction at the center point is obtained. Specifically, in the cross-shaped quadrupolar secondary light source 32 set in the radial polarization state, the polarization direction of the light beam passing through the pair of circular regions 32A facing the Y direction across the optical axis AX is Y The polarization direction of the light beam passing through the pair of circular regions 32B facing each other in the X direction across the optical axis AX is the X direction.

  In this case, the light in the polarization state changed from the required X-direction linear polarization state due to the influence of the optical element that is arranged in the optical path between the polarization state switching system 3 and the polarization conversion unit 13 and changes the polarization state of the light. Is incident on the polarization conversion unit 13, the polarizer 13a returns the polarization state of the incident light to the required X-direction linear polarization state and makes it incident on the polarization conversion element 13b. The polarization conversion element 13b changes the polarization state of the incident light in the required X-direction linear polarization state to the desired radial polarization state and emits it.

  Alternatively, while maintaining the state in which the polarization state switching system 3 emits light in the Z-direction linearly polarized light, the polarization conversion element 13b is rotated from the first posture of FIG. 2 by 90 degrees around the optical axis AX. By setting, it is possible to realize the radially polarized quadrupole illumination shown in FIG. At this time, the posture of the polarizer 13a is maintained in the first posture in which Y-direction linearly polarized light is selected from the incident light and emitted. In this case, even if light in the polarization state changed from the required Y-direction linear polarization state enters the polarization conversion unit 13, the polarizer 13a returns the polarization state of the incident light to the required Y-direction linear polarization state and converts the polarization. Incident light is incident on the element 13b. The polarization conversion element 13b set in the second posture changes the polarization state of the incident light in the required Y-direction linear polarization state to the desired radial polarization state and emits it.

  In general, in the radial polarization illumination based on the multipolar or ring-shaped pupil intensity distribution in the radial polarization state, the light irradiated on the wafer W as the final irradiated surface is a polarization state mainly composed of P-polarized light. become. Here, the P-polarized light is linearly polarized light having a polarization direction in a direction parallel to the incident surface defined as described above (polarized light whose electric vector is oscillating in a direction parallel to the incident surface). is there. As a result, in the radial polarization illumination, a good mask pattern image can be obtained on the wafer (photosensitive substrate) while suppressing the reflectance of light in the resist applied to the wafer W to be small.

  Further, in the above-described embodiment, by switching from the diffractive optical element for cross-type quadrupole illumination to the diffractive optical element for X-type quadrupole illumination, an X-shaped quadrupole secondary as shown in FIG. The light source 33 (33A, 33B) can be formed. Then, the polarization conversion element 13b is set to the third posture rotated from the first posture in FIG. 2 by 45 degrees clockwise around the optical axis AX, and makes 45 degrees with the Z direction and the X direction. 6 is realized by changing the posture of the wave plates 3a and 3b in the polarization state switching system 3 so as to emit oblique linearly polarized light having a polarization direction in an oblique direction. Can do.

  At this time, the posture of the polarizer 13a is obliquely linearly polarized light having a polarization direction in an oblique direction of 45 degrees with respect to the Y direction and the X direction from the first posture in which Y direction linearly polarized light is selected and emitted. Is switched to the third posture for injection. The third posture of the polarizer 13a is obtained by rotating the polarizer 13a from the first posture by 45 degrees around the optical axis AX. The X-shaped quadrupole secondary light source 33 set in the circumferential polarization state passes through a pair of circular regions 33A facing each other in an oblique direction of 45 degrees with the + X direction and the + Y direction across the optical axis AX. The polarization direction of the light beam to be emitted is an oblique direction that forms 45 degrees with the + X direction and the -Y direction. The polarization direction of the light beam passing through the pair of circular regions 33B opposed to each other in an oblique direction that forms 45 degrees with the + X direction and the −Y direction across the optical axis AX is an oblique direction that forms 45 degrees with the + X direction and the + Y direction. Become.

  In this case, the light in the polarization state changed from the required oblique linear polarization state due to the influence of the optical element that is arranged in the optical path between the polarization state switching system 3 and the polarization conversion unit 13 and changes the polarization state of the light. Is incident on the polarization conversion unit 13, the polarizer 13a returns the polarization state of the incident light to the required oblique linear polarization state and makes it incident on the polarization conversion element 13b. The polarization conversion element 13b changes the polarization state of the incident light in the required oblique linear polarization state to the desired circumferential polarization state and emits it.

  In the above-described embodiment, the cross-shaped quadrupole illumination diffractive optical element is switched to the X-shaped quadrupole illumination diffractive optical element, and the polarization conversion element 13b is moved from the first posture of FIG. 2 to the optical axis AX. Polarized so as to emit obliquely linearly polarized light having a polarization direction in the oblique direction forming 45 degrees with the Z direction and the X direction, set to a fourth posture rotated 45 degrees counterclockwise in FIG. By changing the postures of the wave plates 3a and 3b in the state switching system 3, the radially polarized quadrupole illumination based on the X-shaped quadrupole secondary light source 34 (34A and 34B) as shown in FIG. Can be realized.

  At this time, the posture of the polarizer 13a is obliquely linearly polarized light having a polarization direction in an oblique direction of 45 degrees with respect to the Y direction and the X direction from the first posture in which Y direction linearly polarized light is selected and emitted. Is switched to the third posture for injection. The X-shaped quadrupole secondary light source 34 set in the radial polarization state passes through a pair of circular regions 34A opposed to each other in an oblique direction of 45 degrees with the + X direction and the + Y direction with the optical axis AX interposed therebetween. The polarization direction of the luminous flux is an oblique direction that forms 45 degrees with the + X direction and the + Y direction. The polarization direction of the light beam passing through a pair of circular regions 34B facing each other in an oblique direction that forms 45 degrees with the + X direction and the −Y direction across the optical axis AX is an oblique direction that forms 45 degrees with the + X direction and the −Y direction. become.

  In this case, the light in the polarization state changed from the required oblique linear polarization state due to the influence of the optical element that is arranged in the optical path between the polarization state switching system 3 and the polarization conversion unit 13 and changes the polarization state of the light. Is incident on the polarization conversion unit 13, the polarizer 13a returns the polarization state of the incident light to the required oblique linear polarization state and makes it incident on the polarization conversion element 13b. The polarization conversion element 13b changes the polarization state of the incident light in the required oblique linear polarization state to the desired radial polarization state and emits it. The pupil intensity distribution 33 in the X-shaped quadrupole and circumferentially polarized state in FIG. 6 and the pupil intensity distribution in the X-shaped quadrupole and radially polarized state in FIG. 7 are circular regions 33A, 33B, 34A, and 34B. The polarization direction of the light beam passing through the optical element is an oblique direction that forms 45 degrees with the X direction and the Y direction, so that an optical element (especially planar reflection) disposed in the optical path between the polarization state switching system 3 and the polarization conversion unit 13 is used. It is easily affected by the mirror, and it has been difficult to generate accurately by the prior art.

  In the above-described embodiment, the present invention is described by taking quadrupole illumination, circumferential polarization illumination, radial polarization illumination, and the like as examples. However, the present invention is not limited to this, and the present invention is similarly applied to multipolar illumination other than quadrupole illumination, annular illumination, and the like, as well as polarized illumination other than circumferential polarization illumination and radial polarization illumination. Can be applied.

  In the above-described embodiment, the present invention is described by taking the polarization conversion unit 13 having the specific configuration shown in FIGS. 1 and 2 as an example. However, the present invention is not limited to this, and various configurations are possible for the configuration and arrangement of the polarization conversion unit. That is, various forms are possible for the arrangement of the polarization conversion unit, the configuration and arrangement of the polarizer in the polarization conversion unit, the configuration and arrangement of the polarization conversion element, the positional relationship between the polarizer and the polarization conversion element, and the like.

  For example, in the above-described embodiment, the polarization conversion element 13b is configured by the pair of optical rotation members 21A and the pair of optical rotation members 21B. However, the present invention is not limited to this, and a pair of 1/1 / as shown in FIG. The polarization conversion element 13b can also be configured by the two-wave plate 22A and the pair of half-wave plates 22B. Here, the half-wave plate 22A changes incident linearly polarized light into X-direction linearly polarized light, and the half-wave plate 22B changes incident linearly polarized light into Y-direction linearly polarized light. . In general, a polarization conversion element is formed of a birefringent crystal material and has a function of changing the polarization state of incident light. Examples of configurations described) are possible.

  In the above-described embodiment, a wire grid type polarizer is used as the polarizer 13a. However, the polarizer 13a is not limited to this, and the polarizer 13a is disposed at an angle that is substantially a Brewster angle with respect to the traveling direction of the incident light beam. A polarizer having a refracting surface can be used. As shown in FIG. 9, the polarizer using the Brewster angle is composed of a pair of prism array members 41 and 42 having the same form, for example. The prism array members 41 and 42 are manufactured by forming prism arrays on both surfaces of a plane parallel plate using MEMS technology.

  In the polarizer 13c using the Brewster angle, it is incident on the incident-side refractive surface 41a of the first prism array member 41 at an incident angle substantially equal to the Brewster angle (about 56 degrees) along a direction parallel to the optical axis AX. The light is refracted by the incident-side refracting surface 41a, propagates inside the first prism array member 41, is refracted by the exit-side refracting surface 41b parallel to the incident-side refracting surface 41a, and then is parallel to the optical axis AX. Are emitted from the first prism array member 41. Light incident on the incident-side refractive surface 42a of the second prism array member 42 along the direction parallel to the optical axis AX at an incident angle substantially equal to the Brewster angle is refracted by the incident-side refractive surface 42a, and the second prism array. After traveling through the member 42 and being refracted by the exit-side refracting surface 42b parallel to the incident-side refracting surface 42a, the traveling direction of incident light to the first prism array member 41 is parallel to the optical axis AX. Is emitted from the second prism array member 42 along a direction that coincides with the first prism array member 42.

  In the polarizer 13c using the Brewster angle, in accordance with the principle of pile of plates, the transmittance of P-polarized light (Y-direction linearly polarized light) polarized in the vertical direction on the paper surface of FIG. The transmittance of S-polarized light (X-direction linearly polarized light) polarized in the direction perpendicular to the paper surface of FIG. 9 is about 85%. Polarizers utilizing the Brewster angle are disclosed in US Pat. No. 5,934,780, US Pat. No. 6,190,016, US Pat. No. 6,292,296, US Pat. , 307,609 and the like.

  Moreover, in the above-mentioned embodiment, although the single polarizer 13a is arrange | positioned adjacent to the incident side of the polarization conversion element 13b, it is not limited to this, Adjacent to the exit side of the polarization conversion element A configuration in which a plurality of polarizers are arranged is also possible. However, in this case, as shown in FIG. 10, a pair of polarizers 23a is arranged behind the pair of optical rotation members 21A in the polarization conversion element 13b, and a pair of polarizers 23b is arranged behind the pair of optical rotation members 21B. Will be placed. Here, the pair of polarizers 23a selects and emits light in the X direction linear polarization state from the incident light, and the pair of polarizers 23b selects and emits light in the Y direction linear polarization state from the incident light.

  Further, in the above-described embodiment, the polarization conversion unit 13 is disposed at the pupil plane of the imaging optical system 12 or a position near the pupil plane. However, the present invention is not limited to this, and for example, the incident plane of the micro fly's eye lens 9 It is also possible to arrange the polarization conversion unit at a position in the vicinity of, a pupil plane of the afocal lens 5, or a position in the vicinity thereof. In the above-described embodiment, the polarizer 13a is disposed adjacent to the polarization conversion element 13b. However, the present invention is not limited to this, and another optical element is interposed between the polarization conversion element and the polarizer. It is also possible to adopt a configuration.

  In the above-described embodiment, the diffractive optical element 4 is used as a spatial light modulation element that spatially modulates and emits incident light. However, instead of the diffractive optical element 4 or in addition to the diffractive optical element 4, a spatial light modulator having a plurality of optical elements that are two-dimensionally arranged and individually controlled can be used. This type of spatial light modulator is composed of a large number of minute element mirrors that are arranged in an array and whose tilt angle and tilt direction are individually driven and controlled, and divide the incident light beam into minute units for each reflecting surface. By deflecting the light beam, the cross section of the light beam is converted into a desired shape or a desired size. An illumination optical system using such a spatial light modulator is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-353105.

  In the above-described embodiment, a variable pattern forming apparatus that forms a predetermined pattern based on predetermined electronic data can be used instead of a mask. By using such a variable pattern forming apparatus, the influence on the synchronization accuracy can be minimized even if the pattern surface is placed vertically. As the variable pattern forming apparatus, for example, a DMD (digital micromirror device) including a plurality of reflecting elements driven based on predetermined electronic data can be used. An exposure apparatus using DMD is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285 pamphlet and US Patent Publication No. 2007/0296936 corresponding thereto. In addition to a non-light-emitting reflective spatial light modulator such as DMD, a transmissive spatial light modulator may be used, or a self-luminous image display element may be used. Note that a variable pattern forming apparatus may be used even when the pattern surface is placed horizontally. Here, the teachings of US Patent Publication No. 2007/0296936 are incorporated by reference.

  In the above-described embodiment, the micro fly's eye lens 9 is used as the optical integrator, but instead, an internal reflection type optical integrator (typically a rod type integrator) may be used. In this case, the condensing lens is arranged on the rear side of the zoom lens 8 so that the front focal position thereof coincides with the rear focal position of the zoom lens 8, and the incident end is located at or near the rear focal position of the condensing lens. Position the rod-type integrator so that is positioned. At this time, the exit end of the rod integrator is the position of the illumination field stop 11. When using a rod type integrator, a position optically conjugate with the position of the aperture stop of the projection optical system PL in the field stop imaging optical system 12 downstream of the rod type integrator can be called an illumination pupil plane. In addition, since a virtual image of the secondary light source of the illumination pupil plane is formed at the position of the entrance surface of the rod integrator, this position and a position optically conjugate with this position are also called the illumination pupil plane. Can do.

  The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus may be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 11 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 11, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the transfer of the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred is performed (step S46: development process). Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step).

  Here, the resist pattern is a photoresist layer in which unevenness having a shape corresponding to the pattern transferred by the exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. is there. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W or film formation of a metal film or the like. In step S44, the exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as the photosensitive substrate, that is, the plate P.

  FIG. 12 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 12, in the liquid crystal device manufacturing process, a pattern forming process (step S50), a color filter forming process (step S52), a cell assembling process (step S54), and a module assembling process (step S56) are sequentially performed.

  In the pattern forming process of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on the glass substrate coated with a photoresist as the plate P using the exposure apparatus of the above-described embodiment. In this pattern formation process, an exposure process for transferring the pattern to the photoresist layer using the exposure apparatus of the above-described embodiment and development of the plate P to which the pattern is transferred, that is, development of the photoresist layer on the glass substrate are performed. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

  In the color filter forming step of step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction.

  In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

In the above-described embodiment, ArF excimer laser light (wavelength: 193 nm) or KrF excimer laser light (wavelength: 248 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.

  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 technique for filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a technique for locally filling the liquid as disclosed in International Publication No. WO 99/49504, 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 method of forming a liquid tank and holding the substrate in the liquid tank can be employed. Here, the teachings of International Publication No. WO99 / 49504, JP-A-6-124873 and JP-A-10-303114 are incorporated by reference.

  In the above-described embodiment, the present invention is applied to the illumination optical system that illuminates the mask (or wafer) in the exposure apparatus. However, the present invention is not limited to this, and an object other than the mask (or wafer) is used. The present invention can also be applied to a general illumination optical system that illuminates the irradiation surface.

DESCRIPTION OF SYMBOLS 1 Light source 3 Polarization state switching system 4 Diffractive optical element 5 Afocal lens 7 Conical axicon system 8 Zoom lens 9 Micro fly eye lens 10 Condenser optical system 11 Mask blind 12 Imaging optical system 13 Polarization conversion unit 13a Polarizer 13b Polarization conversion element M Mask PL Projection optical system W Wafer

Claims (21)

In the polarization conversion unit that converts the polarization state of the incident light beam into a predetermined polarization state and emits it,
A polarization conversion element that is formed of a birefringent crystal material and changes a polarization state of incident light;
A polarization conversion unit comprising: a polarizer that is disposed on an incident side or an emission side of the polarization conversion element and that selects and emits light having a specific polarization state from incident light. The incident light beam is linearly polarized light;
The polarization conversion element is formed of an optical material having optical rotation and having a first thickness in a plane-parallel plate shape having a first thickness, and an optical material having optical activity and having the first thickness. The polarization conversion unit according to claim 1, further comprising: a second optical rotation member having a parallel plane plate shape and a different second thickness. Used in combination with an illumination optical system that illuminates the illuminated surface with light from a light source,
The polarization conversion element includes a pair of the first optical rotation members arranged to face each other in the first direction across the optical axis of the illumination optical system, and a second that intersects the first direction across the optical axis. The polarization conversion unit according to claim 2, further comprising a pair of the second optical rotation members arranged to face each other. The incident light beam is linearly polarized light;
The polarization conversion element changes a first wavelength plate that changes incident light into light in a first linear polarization state, and changes incident light into light in a second linear polarization state that is different from the first linear polarization state. The polarization conversion unit according to claim 1, further comprising a second wave plate. Used in combination with an illumination optical system that illuminates the illuminated surface with light from a light source,
The polarization conversion element includes a pair of the first wave plates disposed opposite to each other in the first direction across the optical axis of the illumination optical system, and a second that intersects the first direction across the optical axis. The polarization conversion unit according to claim 4, further comprising a pair of the second wave plates disposed so as to face each other in the direction. 6. The polarization conversion unit according to claim 1, wherein the polarizer includes a wire grid type polarizer. 6. The polarizer according to claim 1, wherein the polarizer has a refracting surface disposed at an angle that is substantially a Brewster angle with respect to a traveling direction of the incident light beam. Polarization conversion unit. 8. The polarization conversion unit according to claim 1, wherein the polarizer includes a single polarizer disposed on an incident side of the polarization conversion element. 9. 8. The polarization conversion unit according to claim 1, wherein the polarizer has a plurality of polarizers arranged on an exit side of the polarization conversion element. 9. The polarization conversion unit according to claim 1, wherein the polarization conversion element and the polarizer are adjacent to each other. 11. The optical system according to claim 1, wherein the illumination optical system is used in combination with an illumination optical system that illuminates a surface to be irradiated with light from a light source, and is disposed at or near an illumination pupil of the illumination optical system. The polarization conversion unit described in 1. In the illumination optical system that illuminates the illuminated surface with light from the light source,
An illumination optical system comprising the polarization conversion unit according to any one of claims 1 to 11 disposed in an optical path between the light source and the irradiated surface. The illumination optical system according to claim 12, wherein the polarization conversion unit is disposed at or near an illumination pupil of the illumination optical system. The projection pupil is used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface, and the illumination pupil is at a position optically conjugate with an aperture stop of the projection optical system. 14. The illumination optical system according to 12 or 13. In the illumination optical system that illuminates the illuminated surface with light from the light source,
At least one optical path bending mirror for deflecting the traveling direction of light from the light source;
And a polarizer disposed in an optical path between the light path folding mirror disposed closest to the irradiated surface of the at least one optical path bending mirror and the irradiated surface. Illumination optical system. The illumination optical system according to claim 15, wherein the polarizer is disposed on or near an illumination pupil plane of the illumination optical system. The projection optical system is used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface, and the illumination pupil plane is optically conjugate with an aperture stop of the projection optical system. Item 17. The illumination optical system according to Item 16. The illumination optical system according to any one of claims 15 to 17, wherein the polarizer is a polarizer included in the polarizer unit according to any one of claims 1 to 11. 19. An exposure apparatus comprising the illumination optical system according to claim 12 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. The exposure apparatus according to claim 19, further comprising a projection optical system that forms an image of the predetermined pattern on the photosensitive substrate. An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to claim 19 or 20,
Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

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