JP2013008788A - Polarization conversion unit, illumination optical system, exposure device, and manufacturing method of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarization conversion unit which is arranged in an optical path of an illumination optical system and can realize a pupil intensity distribution in a circumferentially polarized state with good point symmetry with respect to an optical axis while suppressing a light amount loss.
A polarization conversion unit including a polarization conversion member that converts incident light into light having a predetermined polarization state and emits the light. The polarization conversion member has a planar first surface orthogonal to the optical axis, and a second surface having a sawtooth cross section along a circle centered on the optical axis. The second surface of the polarization conversion member has a plurality of first ridges extending radially from a predetermined point on the optical axis along a plane orthogonal to the optical axis, and a side surface of a cone having the predetermined point as a vertex with the optical axis as a center. And a plurality of second ridge lines extending radially from a predetermined point, and a plurality of planar optical surfaces formed between the first ridge line and the second ridge line adjacent to each other.
[Selection] Figure 4

Description

  The present invention relates to a polarization conversion unit, an illumination optical system, an exposure apparatus, and a device manufacturing method.

  In a typical exposure apparatus of this type, a secondary light source (generally an illumination pupil), which is a substantial surface light source composed of a number of light sources, passes through a fly-eye lens as an optical integrator. A predetermined light intensity distribution). Hereinafter, the light intensity distribution in the illumination pupil is referred to as “pupil intensity distribution”. The illumination pupil is a position where the illumination surface becomes the Fourier transform plane of the illumination pupil by the action of the optical system between the illumination pupil and the illumination surface (a mask or a wafer in the case of an exposure apparatus). Defined.

  The light from the secondary light source is collected by the condenser optical system and then illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask forms an image on the wafer via the projection optical system, and the mask pattern is projected and exposed (transferred) onto the wafer. The pattern formed on the mask is miniaturized, and it is indispensable to obtain a uniform illuminance distribution on the wafer in order to accurately transfer the fine pattern onto the wafer.

  In order to realize an illumination condition suitable for accurately transferring a fine pattern in an arbitrary direction, an annular secondary light source is formed on the rear focal plane of the fly-eye lens or in the vicinity of the illumination pupil. Has been proposed (see, for example, Patent Documents), in which a light beam passing through the secondary light source is set in a linear polarization state whose polarization direction is the circumferential direction (hereinafter referred to as “circumferential polarization state” for short). 1).

US Patent Application Publication No. 2006/0170901

  In order to satisfactorily exert the effect of circumferentially polarized light, it is desired to realize a pupil intensity distribution in a circumferentially polarized state with good point symmetry with respect to the optical axis while suppressing light loss.

  The present invention has been made in view of the above-described problems, and is arranged in the optical path of the illumination optical system to obtain a pupil intensity distribution in a circumferentially polarized state with good point symmetry with respect to the optical axis while suppressing light loss. An object is to provide a polarization conversion unit that can be realized. Further, the present invention uses a polarization conversion unit that realizes a pupil intensity distribution in a circumferentially polarized state with good point symmetry with respect to the optical axis to illuminate an irradiated surface with light in a desired circumferentially polarized state. An object of the present invention is to provide an illumination optical system that can be used. In addition, the present invention can accurately transfer a fine pattern onto a photosensitive substrate under an appropriate illumination condition using an illumination optical system that illuminates a predetermined pattern with light having a desired circumferential polarization state. An object of the present invention is to provide an exposure apparatus and a device manufacturing method.

In the first embodiment, in a polarization conversion unit including a polarization conversion member that converts incident light into light having a predetermined polarization state and emits the light,
The polarization conversion unit has a planar first surface orthogonal to the optical axis and a second surface having a sawtooth cross section along a circle centered on the optical axis. I will provide a.

In the second embodiment, in the illumination optical system that illuminates the illuminated surface with 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, there is provided an exposure apparatus comprising the illumination optical system according to the second aspect for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.

In the fourth embodiment, using the exposure apparatus of the third embodiment, exposing the predetermined pattern to the photosensitive substrate;
Developing the photosensitive substrate having the predetermined pattern transferred thereon, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
And processing the surface of the photosensitive substrate through the mask layer. A device manufacturing method is provided.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment. It is a figure which shows a mode that an annular | circular shaped light intensity distribution is formed in an illumination pupil. It is a figure explaining the radial direction polarization | polarized-light state with favorable point symmetry regarding an optical axis. It is a figure which shows schematically the structure of the polarization conversion unit of embodiment. It is a perspective view which shows a mode that a pair of polarization conversion member is arrange | positioned adjacent to each other. It is a perspective view which shows roughly the structure of the polarization conversion member arrange | positioned at the incident side. It is a perspective view which shows roughly the structure of the polarization conversion member arrange | positioned at the output side. It is a figure which shows the parameter which prescribes | regulates the unit part of the polarization conversion member arrange | positioned at the incident side. It is a figure which shows the parameter which prescribes | regulates the unit part of the polarization conversion member arrange | positioned at the output side. It is a figure which shows a mode that the light intensity distribution of an annular | circular shape and a circumferential direction polarization state is formed in an illumination pupil It is a figure which shows a mode that the light intensity distribution of a ring shape and radial direction polarization state is formed in an illumination pupil. It is a figure which shows a mode that the light intensity distribution of 4 pole shape and a radial direction polarization state is formed in an illumination pupil. It is a figure which shows a mode that the light intensity distribution of 4 pole shape and the circumferential direction polarization state is formed in an illumination pupil. It is a figure which shows roughly the structure of the polarization conversion unit concerning a modification. It is a figure which shows roughly the structure of the optical rotation member in FIG. It is a figure which shows the polarization state of the ring-shaped light beam immediately after an optical rotation member. 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.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to the embodiment. In FIG. 1, the Z axis along the normal direction of the exposure surface (transfer surface) of the wafer W, which is a photosensitive substrate, and the Y axis in the direction parallel to the paper surface of FIG. In the W exposure plane, the X axis is set in a 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 LS. As the light source LS, 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 LS enters the afocal lens 4 through the shaping optical system 1, the polarization state switching unit 2, and the diffractive optical element 3. The shaping optical system 1 has a function of converting a substantially parallel light beam from the light source LS into a light beam having a predetermined rectangular cross section and guiding it to the polarization state switching unit 2.

  The polarization state switching unit 2 includes, in order from the light source side, a quarter-wave plate 2a that converts the incident elliptically polarized light into linearly polarized light with the crystal optical axis being rotatable about the optical axis AX, A half-wave plate 2b that changes the polarization direction of the linearly polarized light that is configured so that the crystal optical axis is rotatable about the optical axis AX, and a depolarizer that can be inserted into and removed from the illumination optical path (depolarizing element) 2c. The polarization state switching unit 2 has a function of converting light from the light source LS into linearly polarized light having a desired polarization direction and entering the diffractive optical element 3 with the depolarizer 2c retracted from the illumination optical path. In the state where the depolarizer 2c is set in the illumination optical path, the light from the light source LS is converted into substantially non-polarized light and incident on the diffractive optical element 3.

  The afocal lens 4 includes a front lens group 4a and a rear lens group 4b. The front focal position of the front lens group 4a substantially coincides with the position of the diffractive optical element 3, and the rear focal point of the rear lens group 4b. This is an afocal system (non-focal optical system) set so that the position and the position of the predetermined plane IP indicated by a broken line in the figure substantially coincide with each other. The diffractive optical element 3 is formed by forming a step having a pitch of about the wavelength of exposure light (illumination light) on the substrate, and has a function of diffracting an incident beam to a desired angle. Hereinafter, in order to simplify the explanation, it is assumed that the diffractive optical element 3 is a diffractive optical element for annular illumination.

  The diffractive optical element 3 for annular illumination has a function of forming an annular light intensity distribution in the far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. Therefore, the substantially parallel light beam incident on the diffractive optical element 3 forms a ring-shaped light intensity distribution 21 at the pupil position of the afocal lens 4 as shown in FIG. 4 is injected. A polarization conversion unit 5 and a conical axicon system 6 are disposed at or near the pupil position of the afocal lens 4. The configuration and operation of the polarization conversion unit 5 and the conical axicon system 6 will be described later.

  The light passing through the afocal lens 4 passes through a zoom lens 7 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) 8. The micro fly's eye lens 8 is, for example, an optical element composed of a large number of micro lenses having positive refracting power arranged vertically and horizontally and densely, and by performing etching treatment on a parallel plane plate, a micro lens group is formed. It is configured.

  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. As the micro fly's eye lens 8, for example, a cylindrical micro fly's eye lens can be used. 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 plane IP is disposed at or near the front focal position of the zoom lens 7, and the incident surface of the micro fly's eye lens 8 is disposed at or near the rear focal position of the zoom lens 7. In other words, the zoom lens 7 arranges the predetermined plane IP and the incident surface of the micro fly's eye lens 8 substantially in a Fourier transform relationship, and consequently the pupil surface of the afocal lens 4 and the incident surface of the micro fly's eye lens 8. Are arranged almost conjugate optically.

  Accordingly, on the incident surface of the micro fly's eye lens 8, for example, a ring-shaped illumination field centered on the optical axis AX is formed in the same manner as the pupil surface of the afocal lens 4. The overall shape of the annular illumination field changes in a similar manner depending on the focal length of the zoom lens 7. The light beam incident on the micro fly's eye lens 8 is two-dimensionally divided, and an illumination field formed on the entrance surface of the micro fly's eye lens 8 is positioned at the rear focal plane or in the vicinity thereof (the position of the illumination pupil). A secondary light source having substantially the same light intensity distribution, that is, a ring-shaped secondary light source centered on the optical axis AX as shown in FIG. 2 (substantial surface light source consisting of many small light sources: pupil intensity distribution) 21 ′ Is formed.

  The light beam from the secondary light source 21 ′ formed on the illumination pupil immediately after the micro fly's eye lens 8 illuminates the mask blind 10 in a superimposed manner via the condenser optical system 9. Thus, a rectangular illumination field corresponding to the shape and focal length of the micro lens of the micro fly's eye lens 8 is formed on the mask blind 10 as an illumination field stop. Note that an aperture (light) corresponding to the secondary light source is located at or near the rear focal plane of the micro fly's eye lens 8, that is, at a position optically conjugate with an entrance pupil plane of the projection optical system PL described later. An illumination aperture stop having a transmission part) may be arranged.

  The light that has passed through the rectangular opening (light transmitting portion) of the mask blind 10 passes through the imaging optical system 11 including the front lens group 11a and the rear lens group 11b, and the mask M on which a predetermined pattern is formed. Are illuminated in a superimposed manner. That is, the imaging optical system 11 forms an image of the rectangular opening of the mask blind 10 on the mask M.

  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 6 includes, in order from the light source side, a first prism member 6a 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 6b facing the refractive surface. The concave conical refracting surface of the first prism member 6a and the convex conical refracting surface of the second prism member 6b are complementarily formed so as to be in contact with each other. Further, at least one of the first prism member 6a and the second prism member 6b is configured to be movable along the optical axis AX, and the interval between the first prism member 6a and the second prism member 6b is configured to be variable. Has been.

  Here, in a state where the first prism member 6a and the second prism member 6b are in contact with each other, the conical axicon system 6 functions as a plane parallel plate and has no effect on the annular secondary light source formed. . However, if the first prism member 6a and the second prism member 6b are separated from each other, the width of the annular secondary light source (1/2 of the difference between the outer diameter and the inner diameter of the annular secondary light source) becomes constant. While maintaining, the outer diameter (inner diameter) of the annular secondary light source changes. That is, the annular ratio (inner diameter / outer diameter) and size (outer diameter) of the annular secondary light source change.

  The zoom lens 7 has a function of enlarging or reducing the entire shape of the annular secondary light source in a similar manner. For example, by enlarging the focal length of the zoom lens 7 from a minimum value to a predetermined value, the entire shape of the annular secondary light source is similarly enlarged. In other words, due to the action of the zoom lens 7, both the width and size (outer diameter) change without changing the annular ratio of the annular secondary light source. As described above, the annular ratio and size (outer diameter) of the annular secondary light source can be controlled by the action of the conical axicon system 6 and the zoom lens 7.

  In place of the diffractive optical element 3 for annular illumination, a plurality of diffractive optical elements (not shown) for multipole illumination (two-pole illumination, four-pole illumination, octupole illumination, etc.) are set in the illumination optical path. Polar lighting can be performed. A diffractive optical element for multipole illumination forms 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. Has the function of 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 8 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, the same multipolar secondary light source 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 8.

  Moreover, instead of the diffractive optical element 3 for annular illumination, a normal circular illumination can be performed by setting a diffractive optical element (not shown) 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 8. 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 8. Also, instead of the diffractive optical element 3 for annular illumination, various forms of modified illumination can be performed by setting a diffractive optical element (not shown) having appropriate characteristics in the illumination optical path.

  In the present embodiment, as described above, the secondary light source formed by the micro fly's eye lens 8 is used as a light source, and the mask M arranged on the irradiated surface of the illumination optical system (1 to 11) 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 (1-11). 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 (1 to 11) or a plane optically conjugate with the illumination pupil plane. When the number of wavefront divisions by the micro fly's eye lens 8 is relatively large, the overall light intensity distribution formed on the incident surface of the micro fly's eye lens 8 and the overall light intensity distribution of the entire secondary light source (pupil intensity distribution). ) And a high correlation. For this reason, the light intensity distribution on the incident surface of the micro fly's eye lens 8 and the surface optically conjugate with the incident surface can also be referred to as a pupil intensity distribution. That is, the pupil plane of the afocal lens 4 that is optically conjugate with the incident plane of the micro fly's eye lens 8 can also be called an illumination pupil plane.

  In order to exhibit the effect of circumferentially polarized light satisfactorily, it is desired to realize a pupil intensity distribution in a circumferentially polarized state with good point symmetry with respect to the optical axis. For the same reason, it is also desired to realize a pupil intensity distribution in a radially polarized state with good point symmetry with respect to the optical axis. However, for example, when a pupil intensity distribution in a circumferential polarization state or a radial polarization state is formed using a wire grid polarizer, not only the light amount loss in the wire grid polarizer is significant, but also polarization with good point symmetry with respect to the optical axis. The state cannot be realized.

  Specifically, when forming a quadrupole and radially polarized pupil intensity distribution 31 as shown in FIG. 3, if a wire grid polarizer is used, the polarization direction is as shown in the left diagram of FIG. The surface light sources 31a are the same throughout, and the polarization state of each surface light source 31a is not point-symmetric with respect to the optical axis AX. In the present embodiment, as shown in the diagram on the right side of FIG. 3, the pupil intensity distribution 32 in a radially polarized state having a good point symmetry with respect to the optical axis AX, and the illustration are omitted, but the point symmetry with respect to the optical axis AX is omitted. In order to realize a favorable pupil intensity distribution in the circumferential polarization state, the polarization conversion unit 5 is introduced. In the pupil intensity distribution 32, the polarization direction in each surface light source 32a is radial about the optical axis AX, and the polarization state in each surface light source 32a is point-symmetric with respect to the optical axis AX.

  The polarization conversion unit 5 is disposed at or near the pupil position of the afocal lens 4, that is, at the position of the illumination pupil of the illumination optical system (1 to 11) or in the vicinity thereof. Hereinafter, in order to facilitate understanding of the description, the polarization conversion unit 5 is disposed at a position immediately before the illumination pupil in the optical path of the afocal lens 4 so as to be fixed or detachable with respect to the optical path. Shall. When the diffractive optical element 3 for annular illumination is disposed in the illumination optical path, a light beam having an annular cross section enters the polarization conversion unit 5.

  In the present embodiment, during the annular illumination, the non-polarized light enters the polarization conversion unit 5 due to the action of the polarization state switching unit 2. As shown in FIG. 4, the polarization conversion unit 5 sequentially converts the incident light into light having a predetermined polarization state and emits the light by the polarization conversion member 51 in order from the light incident side. A second polarization conversion member 52 that compensates the deflection action and has a polarization conversion action similar to that of the first polarization conversion member 51, and a half-wave plate 53 that is detachably arranged with respect to the optical path are provided. . Instead of the half-wave plate 53, an optical rotator (optical rotatory member) configured to emit light by rotating the polarization direction of incident linearly polarized light by 90 degrees may be used.

  As shown in FIGS. 4 and 5, the polarization conversion member 51 includes a planar incident surface 51a orthogonal to the optical axis AX and an exit surface 51b having a sawtooth cross section along a circle centered on the optical axis AX. And have. The polarization conversion member 52 includes an incident surface 52a having a sawtooth cross section along a circle centered on the optical axis AX, and a planar exit surface 52b orthogonal to the optical axis AX. The exit surface 51b of the polarization conversion member 51 and the incident surface 52a of the polarization conversion member 52 have complementary surface shapes. As an example, the polarization conversion members 51 and 52 are disposed adjacent to each other so that the exit surface 51b and the entrance surface 52a come into contact with each other.

  As shown in FIG. 6, the exit surface 51b of the polarization conversion member 51 includes a plurality of first ridge lines 51ba extending radially from the point P1 on the optical axis AX along a plane orthogonal to the optical axis AX, and the optical axis AX. A plurality of planes formed between a plurality of second ridge lines 51bb extending radially from the point P1 along the side surface of the cone having the point P1 as a vertex, and a first ridge line 51ba and a second ridge line 51bb adjacent to each other. Shaped optical surface 51bc. That is, the first ridge line 51ba extends in parallel to the XY plane from the point P1, and the second ridge line 51bb extends in a direction inclined with respect to the XY plane from the point P1 in the + Z direction.

  The plurality of first ridge lines 51ba are arranged at an angular interval of 20 degrees along the circumferential direction of a circle centered on the optical axis AX. Similarly, the plurality of second ridge lines 51bb are also arranged at an angular interval of 20 degrees along the circumferential direction of a circle centered on the optical axis AX. A pair of adjacent optical surfaces 51bc among the plurality of planar optical surfaces 51bc is symmetrical with respect to the first ridge line 51ba or the second ridge line 51bb adjacent to the pair of optical surfaces. Therefore, the exit surface 51b of the polarization conversion member 51 has 18 first ridge lines 51ba, 18 second ridge lines 51bb, and 36 plane optical surfaces 51bc that are congruent with each other.

  As shown in FIG. 7, the incident surface 52a of the polarization conversion member 52 includes a plurality of first ridges 52aa extending radially from the point P2 on the optical axis AX along a plane orthogonal to the optical axis AX, and the optical axis AX. A plurality of second ridge lines 52ab extending radially from the point P2 along the side surface of the cone having the point P2 as a vertex as a center, and a plurality of planes formed between the first ridge line 52aa and the second ridge line 52ab adjacent to each other Optical surface 52ac. That is, the first ridge line 52aa extends in parallel to the XY plane from the point P2, and the second ridge line 52ab extends in a direction inclined with respect to the XY plane from the point P2 toward the -Z direction.

  The plurality of first ridge lines 52aa are arranged at an angular interval of 20 degrees along the circumferential direction of a circle centered on the optical axis AX. Similarly, the plurality of second ridge lines 52ab are also arranged at an angular interval of 20 degrees along the circumferential direction of a circle centered on the optical axis AX. A pair of adjacent optical surfaces 52ac among the plurality of planar optical surfaces 52ac is symmetric with respect to the first ridge line 52aa or the second ridge line 52ab adjacent to the pair of optical surfaces. Therefore, the incident surface 52a of the polarization conversion member 52 has 18 first ridgelines 52aa, 18 second ridgelines 52ab, and 36 plane optical surfaces 52ac that are congruent with each other.

  The polarization conversion members 51 and 52 are manufactured by performing etching, machining, or the like on a parallel flat plate formed of an optical material such as quartz or fluorite. Alternatively, the polarization conversion members 51 and 52 are manufactured by combining unit parts including one or a plurality of optical surfaces 51bc and 52ac formed of an optical material such as quartz or fluorite. As described above, the exit surface 51b of the polarization conversion member 51 and the incident surface 52a of the polarization conversion member 52 have complementary surface shapes, so that the polarization conversion member 51 and the polarization conversion member 52 have the same polarization conversion. Demonstrate the effect. Hereinafter, mainly focusing on the polarization conversion member 51, the polarization conversion action common to the polarization conversion members 51 and 52 will be described.

  In FIG. 8, the XY plan view is a view of a unit portion composed of a pair of planar optical surfaces 51 bc sandwiching one second ridge line 51 bb along the direction of the optical axis AX (Z direction). A side view of the A direction is a view of the unit portion along the A direction shown in the XY plan view, and a side view of the B direction is a view of the unit portion along the B direction shown in the XY plan view. A unit portion composed of a pair of planar optical surfaces 51bc sandwiching one second ridge line 51bb is defined by three angle parameters θ1, θ2, θ3 and two dimension parameters α, β.

  The angle θ1 is an angle formed by the hypotenuse corresponding to the optical surface 51bc and the base corresponding to the first ridge line 51ba in the side view in the A direction. The angle θ2 is an angle (10 degrees in this embodiment) formed by the first ridge line 51ba and the second ridge line 51bb in the XY plan view. The angle θ3 is an angle formed by the hypotenuse corresponding to the second ridge line 51bb and the base corresponding to the first ridge line 51ba in the B-direction side view. The dimension α is the length of the hypotenuse corresponding to the optical surface 51bc in the side view in the A direction. The dimension β is the length of the base corresponding to the first ridge line 51ba in the side view in the B direction.

In the XY plan view, the dimension L1 is ½ of the base of the triangle having the pair of first ridges 51ba as the hypotenuse, that is, ½ of the base of the triangle having the pair of hypotenuses corresponding to the optical surface 51bc in the side view in the A direction. The dimension L1 is represented by the following formula (1a). The height L2 of the triangle having a pair of oblique sides corresponding to the optical surface 51bc in the side view in the A direction, that is, the triangular shape having the oblique sides corresponding to the second ridge line 51bb and the base corresponding to the first ridge line 51ba in the side view in the B direction. The height dimension L2 is represented by the following formula (1b).
L1 = α × cos θ1 = β × tan θ2 (1a)
L2 = α × sin θ1 = β × tan θ3 (1b)

  When an unpolarized parallel light beam enters the planar optical surface 51bc along the optical axis AX, p-polarized light with respect to the optical surface 51bc is transmitted with a transmittance of almost 100%, and s-polarized light with respect to the optical surface 51bc. The light transmittance decreases in accordance with the inclination of the optical surface 51bc (the reflectance increases). At this time, the angle θ1 is related to the difference between the transmittance of p-polarized light and the transmittance of s-polarized light, that is, the difference in ps transmittance.

  In the present embodiment, the angle θ1 related to the ps transmittance difference of the optical surface 51bc constituting the exit surface 51b having the sawtooth cross section of the polarization conversion member 51 is related to, for example, the Brewster angle θB with respect to the optical surface 51bc, and the required angle To decide. As a result, the polarization conversion member 51 uses the difference in ps transmittance of the optical surface 51bc to emit an annular parallel light beam when an annular and non-polarized parallel light beam enters along the optical axis AX. Is brought close to a circumferential polarization state with good point symmetry with respect to the optical axis AX.

In order to suppress the light loss of the p-polarized light within the polarization conversion member 51 within 1%, when the polarization conversion member 51 is made of quartz, the polarization conversion member 51 satisfies the following formula (2a). When formed of fluorite, the angle θ1 (unit: degree) may be determined so as to satisfy the following expression (2b). In Formula (2a), θB (quartz) is a Brewster angle (unit: degree) with respect to the optical surface 51bc when the polarization conversion member 51 is formed of quartz. θB (fluorite) is a Brewster angle (unit: degree) with respect to the optical surface 51bc when the polarization conversion member 51 is formed of fluorite.
θB (quartz) -11 <θ1 <θB (quartz) +8 (2a)
θB (fluorite) -12 <θ1 <θB (fluorite) +8 (2b)

  In FIG. 9, the XY plan view is a view of a unit portion composed of a pair of planar optical surfaces 52ac sandwiching one first ridgeline 52aa along the direction of the optical axis AX (Z direction). A direction side view is the figure which looked at the unit part along the A direction shown to XY top view. The angle φ1 is an angle formed by the hypotenuse corresponding to the optical surface 52ac and the second ridge line 52ab and the base corresponding to the XY plane in the side view in the A direction.

The height L2 of the triangle having a pair of oblique sides corresponding to the optical surface 52ac (second ridge line 52ab) in the side view in the A direction of FIG. 9 is a pair of oblique sides corresponding to the optical surface 51bc in the side view in the A direction of FIG. It is the same as the height dimension L2 of the triangle which has, and is represented by the following formula (3a). In the XY plan view of FIG. 9, the height L3 of the triangle having the hypotenuse corresponding to the second ridge line 52ab and the base corresponding to the first ridge line 52aa, that is, the optical surface 52ac (second ridge line 52ab in the side view in the direction A in FIG. ), A dimension L3 that is ½ of the base of a triangle having a pair of hypotenuses is represented by the following equation (3b).
L2 = α × sin θ1 (3a)
L3 = β × sin θ2 (3b)

Therefore, from the equations (1a), (3a), and (3b), the angle θ1 related to the ps transmittance difference of the optical surface 51bc of the polarization conversion member 51 and the ps transmittance difference of the optical surface 52ac of the polarization conversion member 52 are obtained. The relationship shown in the following equation (4) is derived between the angle φ1 and the angle φ1.
tanφ1 = tanθ1 / cosθ2 (4)

  Referring to Expression (4), the angle θ1 related to the ps transmittance difference of the optical surface 51bc of the polarization conversion member 51 is made optical by the polarization conversion member 52 by sufficiently reducing the angle interval θ2 of the ridge lines 51ba, 51bb, 52aa, 52ab. It can be seen that the angle φ1 relating to the ps transmittance difference of the surface 52ac can be brought close to, and as a result, the polarization conversion action of the polarization conversion member 51 can be brought close to the polarization conversion action of the polarization conversion member 52. If the angle interval θ2 is made sufficiently small, the pair of polarization conversion members 51 and 52 have substantially the same polarization conversion action, that is, the polarization state of the incident ring-shaped parallel light flux is a circumference with good point symmetry with respect to the optical axis AX. It has a function of emitting light close to the directional polarization state.

  In the present embodiment, in the polarization conversion unit 5, a pair of polarization conversion members 51 and 52 having substantially the same polarization conversion action are arranged in series in the optical axis AX direction. Therefore, when the half-wave plate 53 is withdrawn from the optical path, when the parallel light beam in a ring-shaped and non-polarized state is incident on the pair of polarization conversion members 51 and 52 along the optical axis AX, the optical surfaces 51bc and 52ac As a result of the polarization conversion action utilizing the difference in ps transmittance, the illumination pupil immediately after the polarization conversion unit 5 has a light intensity distribution 22 in a circumferentially polarized state with good point symmetry with respect to the optical axis AX as shown in FIG. Is formed.

  Similarly, a light intensity distribution 22 ′ in a circumferentially polarized state with good point symmetry with respect to the optical axis AX is also formed on the illumination pupil immediately after the micro fly's eye lens 8. In the circumferential polarization state, the light beam passing through the annular light intensity distribution 22 ′ becomes a linear polarization state having a polarization direction in the tangential direction of the circle with the optical axis AX as the center. Furthermore, the position of another illumination pupil optically conjugate with the illumination pupil immediately after the micro fly's eye lens 8, that is, the pupil position of the imaging optical system 11 and the pupil position of the projection optical system PL (the aperture stop AS is disposed). The annular light intensity distribution is also formed in the circumferential polarization state corresponding to the annular light intensity distribution 22 ′.

  In general, in the circumferential polarization illumination based on the annular intensity distribution in the circumferential polarization state or a multipolar (bipolar, quadrupole, octupole, etc.) pupil intensity distribution, the wafer W as the final irradiated surface is formed. The irradiated light becomes a polarization state mainly composed of s-polarized light. 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). 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 (irradiated surface: the surface of the wafer W). 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).

  On the other hand, when the half-wave plate 53 is disposed in the optical path, when a parallel light beam in an annular shape and unpolarized enters the pair of polarization conversion members 51 and 52 along the optical axis AX, the polarization conversion unit 5 As shown in FIG. 11, a light intensity distribution 23 in a radially polarized state having a good point symmetry with respect to the optical axis AX is formed in the illumination pupil immediately after. Similarly, a light intensity distribution 23 ′ in a radially polarized state with good point symmetry with respect to the optical axis AX is also formed on the illumination pupil immediately after the micro fly's eye lens 8. In the radial polarization state, the light beam passing through the annular light intensity distribution 23 ′ becomes a linear polarization state having a polarization direction in the radial direction of a circle centered on the optical axis AX. Furthermore, the position of another illumination pupil optically conjugate with the illumination pupil immediately after the micro fly's eye lens 8, that is, the pupil position of the imaging optical system 11 and the pupil position of the projection optical system PL (the aperture stop AS is disposed). ), An annular light intensity distribution is formed in a radially polarized state corresponding to the annular light intensity distribution 23 ′.

  In general, in radial polarization illumination based on an annular or multipolar pupil intensity distribution in the radial polarization state, the light irradiated on the wafer W as the final irradiated surface is a polarization state whose main component is p-polarization. become. Here, 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.

  When the zonal illumination diffractive optical element 3 is switched to the quadrupole illumination diffractive optical element in a state where the pupil intensity distributions 23 and 23 ′ in the annular shape and the radially polarized state are formed in the illumination pupil, FIG. As shown in FIG. 4, a pupil intensity distribution 24 in a quadrupolar and radially polarized state is formed on the illumination pupil. Referring to FIGS. 3 and 12, it can be seen that in this embodiment, the action of the polarization conversion unit 5 realizes a pupil intensity distribution in a radially polarized state with good point symmetry with respect to the optical axis AX.

  When the zonal illumination diffractive optical element 3 is switched to the quadrupole illumination diffractive optical element in a state where the pupil intensity distributions 22 and 22 ′ in the annular shape and in the circumferential polarization state are formed in the illumination pupil, FIG. As shown in FIG. 4, a pupil intensity distribution 25 in a quadrupolar and circumferentially polarized state is formed on the illumination pupil. Also in this case, the action of the polarization conversion unit 5 realizes a pupil intensity distribution in a circumferential polarization state with good point symmetry with respect to the optical axis AX. The pair of polarization conversion members 51 and 52 constituting the polarization conversion unit 5 is a light transmission member formed of an optical material such as quartz or fluorite, and the pair of polarization conversion members 51 and 52 are compared with the light amount loss in the wire grid polarizer. The occurrence of light loss in the polarization conversion members 51 and 52 is small.

  As described above, the polarization conversion unit 5 of the present embodiment is arranged in the optical path of the illumination optical system (1 to 11), and suppresses the light amount loss, and has a good circumferential symmetry with respect to the optical axis AX. (Or radial polarization state) pupil intensity distribution can be realized. In the illumination optical system (1 to 11) of the present embodiment, a desired circumferential polarization state is obtained by using the polarization conversion unit 5 that realizes the pupil intensity distribution of the circumferential polarization state with good point symmetry with respect to the optical axis AX. The pattern surface (irradiated surface) of the mask M can be illuminated with light. In the exposure apparatus (1 to WS) of this embodiment, the illumination optical system (1 to 11) that illuminates the pattern surface of the mask M with light in a desired circumferentially polarized state is used to change the pattern of the mask M to be transferred. The fine pattern can be accurately transferred to the wafer W by exerting the effect of circumferentially polarized light satisfactorily under appropriate illumination conditions realized according to the characteristics.

  In the above-described embodiment, the present invention is described based on the polarization conversion unit 5 having the specific configuration shown in FIGS. However, the present invention is not limited to this, and various configurations are possible for the configuration of the polarization conversion unit. Specifically, regarding the arrangement position of the polarization conversion unit, the shape of the polarization conversion member (the shape defined by the angle parameters θ1, θ2, θ3, φ1, dimensional parameters α, β, etc.), material, number, arrangement position, etc. Various forms are possible.

  For example, in the above-described embodiment, the polarization conversion unit 5 is disposed at or near the pupil position of the afocal lens 4. However, the present invention is not limited to this, and the polarization conversion unit 5 can be arranged at the position of the other illumination pupil of the illumination optical system (1 to 11) or a position in the vicinity thereof. Specifically, the polarization conversion unit 5 can be arranged near the entrance surface of the micro fly's eye lens 8, near the exit surface of the micro fly's eye lens 8, the pupil position of the imaging optical system 11, or the vicinity thereof. . Then, the polarization conversion unit 5 may be retracted from the illumination optical path in accordance with a change in the shape of the pupil intensity distribution (and thus a change in illumination conditions). Further, the polarization conversion unit 5 can be replaced with another polarization conversion unit having different characteristics in accordance with a change in the shape or size of the pupil intensity distribution.

  In the above-described embodiment, the polarization conversion unit 5 includes the pair of polarization conversion members 51 and 52. However, various forms of the number of polarization conversion members are possible. For example, by arranging a plurality of assemblies composed of a pair of polarization conversion members in series in the optical axis direction, the point symmetry with respect to the optical axis of the polarization state of the pupil intensity distribution can be further improved. On the other hand, when a light beam having a polarization state in which point symmetry with respect to the optical axis is secured to some extent is incident, a pair of polarization conversion members (in some cases, one polarization conversion member) is used, and the polarization state of the pupil intensity distribution The point symmetry with respect to the optical axis can be set satisfactorily.

  In the polarization conversion unit 5A according to the modification shown in FIG. 14, an optical rotation member 54 that can be inserted into and removed from the optical path is attached to the front side of the polarization conversion member 51 of the polarization conversion unit 5 in the embodiment shown in FIG. . As shown in FIG. 15, the optical rotatory member 54 includes eight parallel plane plate-shaped optical rotators 54 a, 54 b, 54 c, 54 d, 54 e, 54 f, arranged along the circumferential direction of a circle centered on the optical axis AX. 54g, 54h. The optical rotators 54a to 54h are formed of a crystal material that is an optical material having optical activity, such as quartz.

  In a state where the optical rotatory member 54 is positioned in the optical path, the incident surfaces (and thus the exit surfaces) of the optical rotators 54a to 54h are orthogonal to the optical axis AX, and the crystal optical axis thereof is substantially coincident with the direction of the optical axis AX (ie, And substantially coincides with the Z direction which is the traveling direction of the incident light). Further, due to the action of the polarization state switching unit 2 and the diffractive optical element 3 for annular illumination, the polarization conversion unit 5 (and thus the optical rotation member 54) is polarized in the Y direction, for example, in an annular shape centered on the optical axis AX. A Y-direction linearly polarized light beam (hatched portion in FIG. 15) 20 enters.

  The optical rotatory elements 54a to 54h occupy eight divided regions obtained by dividing an annular region around the optical axis AX into eight equal parts along the circumferential direction. In other words, the optical rotation elements 54a to 54h are divided so that eight arc-shaped light beams obtained by dividing the incident ring-shaped light beam 20 into eight equal parts along the circumferential direction pass therethrough. Of the optical rotators 54a to 54h, the pair of optical rotators facing each other with the optical axis AX in between have the same thickness and thus the same polarization conversion characteristics. Alternatively, the pair of optical rotatory elements facing each other with the optical axis AX interposed therebetween have different thicknesses but have the same polarization conversion characteristics.

  Specifically, the pair of optical rotators 54a and 54e, when Y-direction linearly polarized light is incident, do not change the polarization direction (that is, rotate the polarization direction by 0 or 180 degrees). The thickness is set so as to emit polarized light. The pair of optical rotators 54b and 54f, when Y-direction linearly polarized light is incident, change the polarization direction to a direction obtained by rotating the Y direction by −45 degrees (or +135 degrees, that is, 45 degrees counterclockwise in FIG. 15). The thickness is set so as to emit linearly polarized light.

  The pair of optical rotators 54c and 54g emit X-direction linearly polarized light having a polarization direction in the X direction obtained by rotating the Y direction by +90 degrees (or -90 degrees) when Y-direction linearly polarized light is incident. The thickness is set as follows. The pair of optical rotators 54d and 54h have a polarization direction in a direction obtained by rotating the Y direction by +45 degrees (or -135 degrees, that is, 45 degrees clockwise in FIG. 6) when light in the Y direction linearly polarized light enters. The thickness is set so as to emit linearly polarized light.

  As a result, as shown in FIG. 16, the light beam 26 (that is, the light beam incident on the polarization conversion member 51) 26 that has passed through the optical rotation member 54 has a ring-shaped cross section centered on the optical axis AX and is substantially polarized in the circumferential direction. It becomes a state. Specifically, arc-shaped light beams 26a and 26e that have passed through optical rotatory elements 54a and 54e out of annular light beam 26 are linearly polarized in the Y direction. The arc-shaped light beams 26b and 26f having passed through the optical rotators 54b and 54f become −45 degrees oblique linearly polarized light having a polarization direction in an oblique direction obtained by rotating the Y direction by −45 degrees.

  The arc-shaped light beams 26c and 26g that have passed through the optical rotatory elements 54c and 54g become X-direction linearly polarized light having a polarization direction in the X direction obtained by rotating the Y direction by 90 degrees. The arc-shaped light beams 26d and 26h that have passed through the optical rotators 54d and 54h become +45 degrees obliquely linearly polarized light having a polarization direction in an oblique direction obtained by rotating the Y direction by +45 degrees. However, a manufacturing error is likely to occur with respect to the thickness of the optical rotators 54a to 54h, and an angular error is likely to occur with respect to the polarization direction of the arc-shaped light beams 26a to 26h.

  In the modified example of FIG. 14, the circumferentially polarized light flux 26 with a certain degree of point symmetry with respect to the optical axis AX is incident on the pair of polarization conversion members 51 and 52 by the action of the optical rotation member 54. Therefore, the pupil intensity distribution formed through the pair of polarization conversion members 51 and 52 is point-symmetric with respect to the optical axis AX as compared with the case where the light beam is incident on the pair of polarization conversion members 51 and 52 in a non-polarized state. In a good circumferential polarization state.

  In the above-described embodiment, the micro fly's eye lens 8 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 7 so that the front focal position thereof coincides with the rear focal position of the zoom lens 7, 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 10. When a rod type integrator is used, a position optically conjugate with the position of the aperture stop of the projection optical system PL in the field stop imaging optical system 11 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.

  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. As the variable pattern forming apparatus, for example, a spatial light modulation element including a plurality of reflection elements driven based on predetermined electronic data can be used. An exposure apparatus using a spatial light modulator is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285, and US Patent Publication No. 2007/0296936 corresponding thereto. In addition to the non-light-emitting reflective spatial light modulator as described above, a transmissive spatial light modulator may be used, or a self-luminous image display element may be used.

  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. 17 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 17, 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 a photosensitive substrate.

  FIG. 18 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 18, in the liquid crystal device manufacturing process, a pattern formation process (step S50), a color filter formation process (step S52), a cell assembly process (step S54), and a module assembly 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 method for filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method 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 Application Laid-Open No. 6-124873 in a liquid bath, or a predetermined depth on a stage as disclosed in Japanese Patent Application Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed. In addition, the method disclosed in, for example, European Patent Application No. 1420298, International Publication No. 2004/055803, US Patent No. 6,952,253, and the like can be applied. Here, the pamphlet of International Publication No. WO99 / 49504, JP-A-6-124873, JP-A-10-303114, European Patent Application Publication No. 1420298, International Publication No. 2004/055803 and US Pat. No. 6,952 No. 253, incorporated herein by reference.

  Further, in the above-described embodiment, in place of or in addition to the diffractive optical element 3, for example, a large number of minute element mirrors arranged in an array and whose tilt angle and tilt direction are individually driven and controlled. A spatial light modulator that converts the cross section of the light beam into a desired shape or a desired size by dividing the incident light beam into minute units for each reflecting surface and deflecting the incident light beam may be used. 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, 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.

2 Polarization state switching unit 3 Diffractive optical element 4 Afocal lens 5 Polarization conversion units 51 and 52 Polarization conversion member 53 1/2 wavelength plate 54 Optical rotation member 6 Conical axicon system 7 Zoom lens 8 Micro fly's eye lens (optical integrator)
9 Condenser optical system 10 Mask blind 11 Imaging optical system LS Light source M Mask MS Mask stage PL Projection optical system W Wafer WS Wafer stage

Claims (14)

In a polarization conversion unit including a polarization conversion member that converts incident light into light having a predetermined polarization state and emits the light,
The polarization conversion unit has a planar first surface orthogonal to the optical axis and a second surface having a sawtooth cross section along a circle centered on the optical axis. . The second surface of the polarization conversion member has a plurality of first ridgelines extending radially from a predetermined point on the optical axis along a plane orthogonal to the optical axis, and the predetermined point is centered on the optical axis. A plurality of second ridge lines extending radially from the predetermined point along the side surface of the cone, and a plurality of planar optical surfaces formed between the first ridge line and the second ridge line adjacent to each other. The polarization conversion unit according to claim 1, comprising: The plurality of first ridge lines are arranged at predetermined angular intervals along a circumferential direction of a circle around the optical axis,
3. The polarization conversion unit according to claim 2, wherein a pair of adjacent optical surfaces among the plurality of planar optical surfaces is symmetric with respect to a second ridge line adjacent to the pair of optical surfaces. It further includes a complementary polarization conversion member having a third surface having a surface shape complementary to the second surface of the polarization conversion member, and a planar fourth surface orthogonal to the optical axis. The polarization conversion unit according to any one of claims 1 to 3. The polarization conversion unit according to claim 4, wherein the polarization conversion member and the complementary polarization conversion member are disposed adjacent to each other. The polarization conversion unit according to claim 4 or 5, comprising a plurality of sets of the polarization conversion member and the complementary polarization conversion member. The polarization conversion unit according to any one of claims 1 to 6, further comprising a half-wave plate arranged on the most exit side. 8. The optical path of an illumination optical system that illuminates a surface to be irradiated with light from a light source, wherein the illumination optical system is disposed at or near an illumination pupil of the illumination optical system. The polarization conversion unit described. In the illumination optical system that illuminates the illuminated surface with light from the light source,
9. An illumination optical system comprising the polarization conversion unit according to claim 1 disposed in an optical path between the light source and the irradiated surface. The illumination optical system according to claim 9, 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. The illumination optical system according to 10. An exposure apparatus comprising the illumination optical system according to any one of claims 9 to 11 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. The exposure apparatus according to claim 12, further comprising a projection optical system that forms an image of the predetermined pattern on the photosensitive substrate. Using the exposure apparatus according to claim 12 or 13, exposing the predetermined pattern to the photosensitive substrate;
Developing the photosensitive substrate having the predetermined pattern transferred thereon, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
Processing the surface of the photosensitive substrate through the mask layer. A device manufacturing method comprising:

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