WO2010016288A1

WO2010016288A1 - Illumination optical system, exposure apparatus, and device manufacturing method

Info

Publication number: WO2010016288A1
Application number: PCT/JP2009/053631
Authority: WO
Inventors: 雅也山本; 梨沙吉元
Original assignee: 株式会社ニコン
Priority date: 2008-08-08
Filing date: 2009-02-27
Publication date: 2010-02-11

Abstract

An illumination condition with diversity in the shape and size of an illumination pupil luminance distribution is achieved. An illumination optical system for illuminating a surface to be irradiated on the basis of light from a light source is provided with a light flux conversion element (32) for converting a light flux incident along a first illumination light path into a light flux having a predetermined cross section to fixedly form a light intensity distribution on an illumination pupil, a first light guide member (31) for guiding the incident light to a second illumination light path, which is insertably provided in the first illumination light path, a spatial light modulator (34, 35) for variably spatially modulating the light incident along the second illumination light path through the first light guide member in order to variably form the light intensity distribution on the illumination pupil, and a second light guide member (33) for guiding the light incident along the second illumination light path through the spatial light modulator to the first illumination light path. The first light guide member is movable in an X-direction that crosses a YZ plane including the first illumination light path and the second illumination light path.

Description

Illumination optical system, exposure apparatus, and device manufacturing method

The present invention relates to 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 devices such as a semiconductor element, an image sensor, a liquid crystal display element, and a thin film magnetic head in a lithography process.

In a typical exposure apparatus of this type, a light beam emitted from a light source is passed through a fly-eye lens as an optical integrator, and a secondary light source (generally an illumination pupil) as a substantial surface light source composed of a number of light sources. A predetermined light intensity distribution). Hereinafter, the light intensity distribution in the illumination pupil is referred to as “illumination pupil luminance 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 beam from the secondary light source is condensed by the condenser lens 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 highly integrated, and it is indispensable to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

Conventionally, there has been proposed an illumination optical system capable of performing modified illumination such as annular illumination and multipolar illumination (bipolar illumination, quadrupole illumination, etc.) using a plurality of replaceable diffractive optical elements (patent) Reference 1). In the illumination optical system disclosed in Patent Document 1, for example, a diffractive optical element for annular illumination that forms an annular illumination pupil luminance distribution in a fixed manner, illumination with multiple poles (bipolar, quadrupole, etc.) By setting one diffractive optical element selected from a diffractive optical element for multipole illumination that forms a fixed pupil luminance distribution in the illumination optical path, the illumination pupil luminance distribution (and thus the illumination condition) is discretely set. It has changed.

JP 2004-56103 A

In the illumination optical system described in Patent Document 1, in order to increase the degree of freedom in changing the shape and size of the illumination pupil luminance distribution, a relatively large number of diffractive optical elements having different characteristics are prepared. It is necessary to switch the element with respect to the illumination optical path. In an actual illumination optical system, the number of replaceable diffractive optical elements is limited, and it is difficult to realize illumination conditions that are sufficiently diverse with respect to the shape and size of the illumination pupil luminance distribution.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an illumination optical system capable of realizing a wide variety of illumination conditions with respect to the shape and size of the illumination pupil luminance distribution. . In addition, the present invention uses an illumination optical system that realizes a wide variety of illumination conditions, and performs good exposure under appropriate illumination conditions realized according to the characteristics of the pattern to be transferred. An object of the present invention is to provide an exposure apparatus that can perform this.

In order to solve the above problems, according to a first aspect of the present invention, in an illumination optical system that illuminates an irradiated surface based on light from a light source, a light beam incident along a first illumination light path is a light beam having a predetermined cross section. And a light beam conversion element that fixedly forms a light intensity distribution on the illumination pupil in the first illumination optical path, and is inserted in the first illumination optical path, and is provided along the first illumination optical path. A first light guide member that guides incident light to the second illumination optical path, and incident along the second illumination optical path through the first light guide member to variably form a light intensity distribution in the illumination pupil. A spatial light modulator that variably imparts spatial modulation to the light, and a second light guide member that guides light incident along the second illumination light path through the spatial light modulator to the first illumination light path The first light guide member includes the first illumination light path and the second illumination light path. Providing an illumination optical system, characterized in that it is movable in a direction intersecting the free surface.

In the second aspect of the present invention, in the illumination optical system that illuminates the irradiated surface based on the light from the light source, the light beam incident along the first illumination light path is converted into a light beam having a predetermined cross section, and the first A light flux conversion element that forms a light intensity distribution in a fixed manner in the illumination pupil in the illumination optical path, and a second illumination optical path that is provided so as to be insertable into the first illumination optical path and that is incident along the first illumination optical path. In order to variably form a light intensity distribution in the illumination pupil and the first light guide member that leads to the light, spatial modulation is applied to light incident along the second illumination light path through the first light guide member. A spatial light modulator that is variably applied; and a second light guide member that guides light incident along the second illumination light path through the spatial light modulator to the first illumination light path, and the spatial light modulation. An extension surface of the installation surface on which the light modulation surface of the device is located forms an acute angle with the first illumination light path. Insert it provides an illumination optical system, characterized in that.

In the third aspect of the present invention, in the spatial light modulation unit used together with the illumination optical system that illuminates the illuminated surface based on the light from the light source, the first illumination light path is provided so as to be inserted into the first illumination light path. A first light guide member that includes a dividing member that divides the light incident along the first light into a plurality of light traveling in a plurality of different directions, and guides the light incident along the first illumination light path to the plurality of second illumination light paths And, in order to variably form a light intensity distribution at the illumination pupil in the first illumination light path, spatially pass through each of the light incident along the plurality of second illumination light paths via the first light guide member. A plurality of spatial light modulators that variably apply various modulations, and a second light guide that guides light incident along the plurality of second illumination light paths through the plurality of spatial light modulators to the first illumination light path A plurality of spatial light modulators. Providing spatial light modulation unit, characterized in that it is fixedly disposed in the second illumination optical path.

According to a fourth aspect of the present invention, there is provided an illumination optical system comprising the spatial light modulation unit of the third aspect, and illuminating an irradiated surface based on light from a light source via the spatial light modulation unit. To do.

According to a fifth aspect of the present invention, the illumination optical system according to the first, second, or fourth aspect for illuminating a predetermined pattern is provided, and the predetermined pattern is exposed on a photosensitive substrate. An exposure apparatus is provided.

In the sixth embodiment of the present invention, using the exposure apparatus of the fifth embodiment, an exposure step of exposing the predetermined pattern to the photosensitive substrate, and developing the photosensitive substrate to which the predetermined pattern is transferred, A development step for forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate; and a processing step for processing the surface of the photosensitive substrate through the mask layer. A device manufacturing method is provided.

In the illumination optical system according to the present invention, a light beam conversion element that fixedly forms a light intensity distribution on the illumination pupil and a spatial light modulator that variably forms a light intensity distribution on the illumination pupil are provided with respect to the illumination optical path. It is provided so that it can be switched. Therefore, for example, by setting a light beam conversion element selected from a plurality of light beam conversion elements in the illumination optical path, the illumination pupil luminance distribution (and thus the illumination condition) is changed discretely, and the illumination pupil is operated by the action of the spatial light modulator. It is possible to freely and quickly change the light intensity distribution, that is, the illumination pupil luminance distribution formed in the above.

Further, in the spatial light modulation unit according to the present invention, a light beam conversion element that forms a fixed light intensity distribution on the illumination pupil without moving the spatial light modulator that variably forms the light intensity distribution on the illumination pupil; Can be switched.

Thus, in the illumination optical system of the present invention, it is possible to realize various illumination conditions with respect to the shape and size of the illumination pupil luminance distribution. The exposure apparatus of the present invention uses the illumination optical system that realizes a wide variety of illumination conditions, and performs good exposure under appropriate illumination conditions realized according to the characteristics of the pattern to be transferred. Which can be done and thus a good device can be produced.

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 internal structure of the spatial light modulation unit of FIG. It is a perspective view which shows the structure of a cylindrical micro fly's eye lens. It is a perspective view which shows roughly the principal part structure of the insertion / extraction mechanism of a diffractive optical element. It is a perspective view which shows roughly the structure of the frame member holding a microprism array and a reflection member. It is a figure explaining the effect | action of a spatial light modulator. It is a fragmentary perspective view of a spatial light modulator. It is a figure which shows typically the light intensity distribution of 4 pole shape formed in the pupil plane of a relay optical system. It is a figure which shows roughly the structural example of the spatial light modulation unit using a single spatial light modulator. It is a figure which shows roughly the structural example of the spatial light modulation unit which uses a pyramid prism as a division member. It is a figure which shows roughly the structural example of the spatial light modulation unit which uses a V-shaped prism as a division 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.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source; 3 Spatial light modulation unit; 31 Micro prism array 32 Diffractive optical element; 33 Reflective member; 34,35 Spatial light modulator 36 Relay optical system; 37 Aperture stop; 4 Afocal lens 7 Zoom lens; Eye lens 10 Condenser optical system; 11 Mask blind; 12 Imaging optical system M Mask; PL Projection optical system; W wafer

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. FIG. 2 is a diagram schematically showing the internal configuration of the spatial light modulation unit of FIG. In FIG. 1, the Z-axis is along the normal direction of the transfer surface (exposure surface) of the wafer W, which is a photosensitive substrate, and the Y-axis is in the direction parallel to the paper surface of FIG. In the W transfer surface, the X axis is set in a direction perpendicular to the paper surface of FIG.

Referring to FIG. 1, exposure light (illumination light) is supplied from a light source 1 in the exposure apparatus of this embodiment. 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 emitted from the light source 1 is expanded into a light beam having a required cross-sectional shape by the shaping optical system 2 and then enters the spatial light modulation unit 3.

As shown in FIG. 2, the spatial light modulation unit 3 is in a first illumination optical path (hereinafter also simply referred to as “illumination optical path” or “optical path”) along the optical axis AX that is the basic optical axis of the illumination optical system. A microprism array (or prism array) 31 that can be installed at a predetermined position, and a plurality of diffractive optics that can be selectively installed at a predetermined position in the first illumination optical path (for example, substantially the same position as the installation position of the microprism array 31). An element 32 and a reflection member 33 that can be installed at a position in the first illumination optical path behind the installation position of the microprism array 31 are provided.

In addition, the spatial light modulation unit 3 includes a pair of spatial

light modulators

34 and 35 that are fixedly installed outside the first illumination light path, and a first illumination light path on the rear side of the installation position of the reflection member 33. A relay optical system 36 installed at a position, and a plurality of aperture stops 37 that can be selectively installed in the first illumination optical path between the front lens group 36a and the rear lens group 36b of the relay optical system 36. ing. The specific configuration and operation of the spatial light modulation unit 3 will be described later. In the following description, in order to facilitate understanding of the configuration and operation of the exposure apparatus, a diffractive optical element 32 for annular illumination is installed in the illumination optical path, and the microprism array 31 and the reflecting member 33 are in the illumination optical path. It is assumed that it is not installed in

In this case, light from the light source 1 via the shaping optical system 2 enters the diffractive optical element 32 for annular illumination along the optical axis AX. For example, when a parallel light beam having a rectangular cross section is incident along the optical axis AX, the diffractive optical element 32 has an annular light intensity distribution centered on the optical axis AX in the far field (or Fraunhofer diffraction region). It has the function to form. The light emitted from the spatial light modulation unit 3 through the diffractive optical element 32 and the relay optical system 36 enters the afocal lens 4.

The afocal lens 4 is an afocal system (non-focal optical system), and is set so that the front focal position and the position of the diffractive optical element 32 are optically conjugate via the relay optical system 36. ing. Further, the rear focal position of the afocal lens 4 and the position of the predetermined surface 5 indicated by a broken line in the figure are set so as to substantially coincide. Therefore, the light that has passed through the diffractive optical element 32 as a light beam conversion element has, for example, an annular shape centered on the optical axis AX on the pupil plane 4c of the afocal lens 4 (see FIG. 2; not shown in FIG. 1). After forming the light intensity distribution, the light is emitted from the afocal lens 4 with an annular angular distribution. In the optical path between the front lens group 4a and the rear lens group 4b of the afocal lens 4, a conical axicon system 6 is disposed at the position of the pupil plane 4c or in the vicinity thereof. The configuration and operation of the conical axicon system 6 will be described later.

The light beam that has passed 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 a cylindrical micro fly's eye lens 8. Is incident on. As shown in FIG. 3, the cylindrical micro fly's eye lens 8 includes a first fly eye member 8a disposed on the light source side and a second fly eye member 8b disposed on the mask side. On the light source side surface of the first fly eye member 8a and the light source side surface of the second fly eye member 8b, cylindrical lens groups 8aa and 8ba arranged side by side in the X direction are formed at a pitch p1, respectively. Cylindrical lens groups 8ab and 8bb arranged side by side in the Z direction on the mask side surface of the first fly eye member 8a and the mask side surface of the second fly eye member 8b, respectively, with a pitch p2 (p2> p1). Is formed.

Focusing on the refraction action in the X direction of the cylindrical micro fly's eye lens 8 (that is, the refraction action in the XY plane), the parallel luminous flux incident along the optical axis AX is formed on the light source side of the first fly eye member 8a. The wavefront is divided by the lens group 8aa along the X direction at the pitch p1, and after receiving the light condensing action on the refracting surface, the corresponding one of the cylindrical lens groups 8ba formed on the light source side of the second fly's eye member 8b. The light is focused on the refracting surface of the cylindrical lens and focused on the rear focal plane of the cylindrical micro fly's eye lens 8.

Focusing on the refractive action in the Z direction of the cylindrical micro fly's eye lens 8 (that is, the refractive action in the YZ plane), the parallel light beam incident along the optical axis AX is formed on the cylindrical side of the first fly's eye member 8a on the mask side. After the wavefront is divided at the pitch p2 along the Z direction by the lens group 8ab, and after receiving the light condensing action on the refracting surface, the corresponding one of the cylindrical lens groups 8bb formed on the mask side of the second fly's eye member 8b. The light is focused on the refracting surface of the cylindrical lens and focused on the rear focal plane of the cylindrical micro fly's eye lens 8.

As described above, the cylindrical micro fly's eye lens 8 is constituted by the first fly eye member 8a and the second fly eye member 8b in which the cylindrical lens groups are arranged on both side surfaces, but the size of p1 is set in the X direction. It has an optical function similar to that of a micro fly's eye lens in which a large number of rectangular minute refracting surfaces having a size of p2 in the Z direction are integrally formed vertically and horizontally. In the cylindrical micro fly's eye lens 8, a change in distortion due to variations in the surface shape of the micro-refractive surface is suppressed to be small, and for example, manufacturing errors of a large number of micro-refractive surfaces integrally formed by etching process give the illuminance distribution. The influence can be kept small.

The position of the predetermined surface 5 is disposed in the vicinity of the front focal position of the zoom lens 7, and the incident surface of the cylindrical micro fly's eye lens 8 is disposed in the vicinity of the rear focal position of the zoom lens 7. In other words, in the zoom lens 7, the predetermined surface 5 and the incident surface of the cylindrical micro fly's eye lens 8 are arranged substantially in a Fourier transform relationship, and as a result, the pupil surface of the afocal lens 4 and the cylindrical micro fly's eye lens 8. The incident surface is optically substantially conjugate.

Therefore, on the incident surface of the cylindrical micro fly's eye lens 8, as in the pupil plane of the afocal lens 4, for example, an annular illumination field composed of an annular light intensity distribution around the optical axis AX is formed. The The overall shape of the annular illumination field changes in a similar manner depending on the focal length of the zoom lens 7. The rectangular micro-refractive surface as a wavefront division unit in the cylindrical micro fly's eye lens 8 has a rectangular shape similar to the shape of the illumination field to be formed on the mask M (and thus the shape of the exposure region to be formed on the wafer W). It is.

The light beam incident on the cylindrical micro fly's eye lens 8 is two-dimensionally divided, and has two light intensity distributions on the rear focal plane or in the vicinity thereof (and thus the illumination pupil) having substantially the same light intensity distribution as the illumination field formed by the incident light beam. A secondary light source (annular illumination pupil luminance distribution) consisting of a secondary light source, that is, a substantial annular light source having an optical axis AX as a center is formed. A light beam from a secondary light source formed on the rear focal plane of the cylindrical micro fly's eye lens 8 or in the vicinity thereof enters an aperture stop 9 disposed in the vicinity thereof.

The aperture stop 9 has an annular opening (light transmission part) corresponding to the annular secondary light source formed at or near the rear focal plane of the cylindrical micro fly's eye lens 8. The aperture stop 9 is configured to be detachable with respect to the illumination optical path, and is configured to be switchable between a plurality of aperture stops having openings 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 aperture stop 9 is disposed at a position that is optically conjugate with an entrance pupil plane of the projection optical system PL described later, and defines a range that contributes to illumination of the secondary light source.

The light from the secondary light source limited by the aperture stop 9 illuminates the mask blind 11 in a superimposed manner via the condenser optical system 10. Thus, a rectangular illumination field corresponding to the shape and focal length of the rectangular micro-refractive surface which is the wavefront division unit of the cylindrical micro fly's eye lens 8 is formed on the mask blind 11 as the illumination field stop. The light beam that has passed through the rectangular opening (light transmitting portion) of the mask blind 11 receives the light condensing action of the imaging optical system 12 and then illuminates the mask M on which a predetermined pattern is formed 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.

The light beam transmitted through the mask M held on the mask stage MS forms an image of a mask pattern on the wafer (photosensitive substrate) W held on the wafer stage WS through the projection optical system PL. In this way, batch exposure or scan exposure is performed while the wafer stage WS is two-dimensionally driven and controlled in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, and thus the wafer W is two-dimensionally driven and controlled. As a result, the pattern of the mask M is sequentially exposed in each exposure region of the wafer W.

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 concave conical refracting surface of the first prism member 6a and the second prism member 6b. The distance from the convex conical refracting surface is variable. Hereinafter, in order to facilitate understanding, the operation of the conical axicon system 6 and the operation of the zoom lens 7 will be described by focusing on the annular or quadrupolar secondary light source.

In a state in which the concave conical refracting surface of the first prism member 6a and the convex conical refracting surface of the second prism member 6b are in contact with each other, the conical axicon system 6 functions as a parallel flat plate, and is formed in an annular shape. Alternatively, there is no influence on the quadrupolar secondary light source. However, if the concave conical refracting surface of the first prism member 6a and the convex conical refracting surface of the second prism member 6b 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 7 has a function of enlarging or reducing the entire shape of the annular or quadrupolar secondary light source in a similar (isotropic) manner. For example, by enlarging the focal length of the zoom lens 7 from a minimum value to a predetermined value, the overall shape of the annular or quadrupolar 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) of the annular or quadrupolar secondary light source change without changing. As described above, the annular ratio and the size (outer diameter) of the annular or quadrupolar secondary light source can be controlled by the action of the conical axicon system 6 and the zoom lens 7.

In this embodiment, as described above, the secondary light source formed by the cylindrical micro fly's eye lens 8 is used as a light source, and the mask M disposed on the irradiated surface of the illumination optical system (2 to 12) 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 to 12). 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 illumination pupil luminance distribution is a light intensity distribution (luminance distribution) on the illumination pupil plane of the illumination optical system (2 to 12) or a plane optically conjugate with the illumination pupil plane.

When the number of wavefront divisions by the cylindrical micro fly's eye lens 8 is relatively large, the overall light intensity distribution formed on the incident surface of the cylindrical micro fly's eye lens 8 and the overall light intensity distribution of the entire secondary light source (illumination Pupil luminance distribution). For this reason, the light intensity distribution on the incident surface of the cylindrical micro fly's eye lens 8 and a surface optically conjugate with the incident surface can also be referred to as an illumination pupil luminance distribution. In the configuration of FIG. 1, the spatial light modulation unit 3, the afocal lens 4, the zoom lens 7, and the cylindrical micro fly's eye lens 8 form an illumination pupil luminance distribution on the illumination pupil behind the cylindrical micro fly's eye lens 8. The distribution forming optical system is configured.

In the spatial light modulation unit 3 of the present embodiment, as shown in FIG. 4, it can rotate around an axis parallel to the optical axis AX, for example, an axis 32a extending in the Y direction with a spacing in the + X direction from the optical axis AX. A plurality of diffractive optical elements 32 having different characteristics are attached to the rotating plate 32b. A fan-shaped notch 32ba defined by a pair of line segments passing through the axis 32a is formed on the rotary plate 32b, and the plurality of diffractive optical elements 32 rotate at intervals along a circle centering on the axis 32a. It is attached to the plate 32b. Thus, the desired diffractive optical element 32 is selectively installed at a predetermined position in the first illumination optical path by the rotation of the rotating plate 32b about the axis 32a. In addition, by positioning the notch 32ba in the first illumination optical path, a state where the diffractive optical element 32 is not installed in the first illumination optical path is realized.

In the spatial light modulation unit 3, instead of the diffractive optical element for annular illumination, a diffractive optical element for multipole illumination (bipolar illumination, quadrupole illumination, octopole illumination, etc.) is set in the illumination optical path. Multi-pole illumination 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. It has the function to do. Therefore, the light beam that has passed through the diffractive optical element for multipole illumination is irradiated on the incident surface of the cylindrical micro fly's eye lens 8 with, for example, a plurality of predetermined shapes (arc shape, circular shape, etc.) centered on the optical axis AX. A multipolar illumination field consisting of As a result, the same multipolar illumination pupil luminance distribution as that of the illumination field formed on the entrance surface is formed on the rear focal plane of the cylindrical micro fly's eye lens 8 or on the illumination pupil in the vicinity thereof.

Further, instead of the diffractive optical element for annular 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 cylindrical micro fly's eye lens 8. As a result, an illumination pupil luminance distribution having the same circular shape as the illumination field formed on the entrance surface is also formed on the illumination pupil at or near the rear focal plane of the cylindrical micro fly's eye lens 8. Further, various forms of modified illumination can be performed by setting a diffractive optical element having appropriate characteristics in the illumination optical path instead of the diffractive optical element for annular illumination.

In the spatial light modulation unit 3 of the present embodiment, when the pair of spatial

light modulators

34 and 35 are used, the diffractive optical element 32 is retracted from the first illumination optical path, and the microprism array 31 and the reflecting member 33 are shaped into the shaping optical system 2. And the first illumination optical path between the relay optical system 36 and the front lens group 36a. For example, as shown in FIG. 5, the microprism array 31 and the reflecting member 33 are held by a frame member 30 having a rectangular opening along the XY plane. Therefore, by moving the frame member 30 in the + X direction and positioning the frame member 30 at the notch 32ba of the rotating plate 32b, the microprism array 31 and the reflecting member 33 can be respectively installed at predetermined positions in the first illumination optical path. . Further, by moving the frame member 30 in the −X direction from the notch 32ba of the rotating plate 32b, the microprism array 31 and the reflecting member 33 can be retracted from the first illumination optical path.

As shown in FIG. 2, in a state where the microprism array 31 and the reflecting member 33 are respectively installed at predetermined positions in the first illumination optical path, the microprism array is along the optical axis AX (along the first illumination optical path). The light incident on 31 is divided into a first light traveling along the optical axis AX1 and a second light traveling along the optical axis AX2. The optical axis AX1 and the optical axis AX2, for example, correspond to the normal direction of one surface and the normal direction of the other surface of the crest-shaped exit surfaces of the prism elements constituting the microprism array 31, respectively. It extends in a direction symmetric with respect to the optical axis AX along the YZ plane including the axis AX.

Further, the first illumination optical path defined by the optical axis AX and the second illumination optical path defined by the optical axis AX1 intersect at an acute angle, and the third illumination optical path defined by the first illumination optical path and the optical axis AX2. Intersects with an acute angle. Here, “the first illumination optical path and the second illumination optical path (third illumination optical path) intersect at an acute angle” means that the optical axis AX defining the first illumination optical path and the second illumination optical path (second Line segment extending from the intersection with the optical axis AX1 (AX2) defining the three illumination optical paths) to the rear side (irradiated surface side) along the optical axis AX, and the rear along the optical axis AX1 (AX2) from the intersection This means that the angle formed with the line segment extending to the side is an acute angle.

The first light traveling along the second illumination light path through the microprism array 31 passes through one opening of the frame member 30 and enters the first spatial light modulator 34. The light modulated by the first spatial light modulator 34 is reflected by the first reflecting surface 33a of the triangular prism-shaped reflecting member 33 extending along the X direction, for example, and guided to the relay optical system 36. On the other hand, the second light traveling along the third illumination light path through the microprism array 31 passes through the other opening of the frame member 30 and enters the second spatial light modulator 35.

Note that the first light traveling along the second illumination optical path through the microprism array 31 has a plurality of stripe-shaped light beam cross sections immediately after the microprism array 31, but the light beam from the light source is a completely parallel light beam. Since the light beam has a slight divergence angle, the cross-sectional shape of the light beam at the position of the first spatial light modulator 34 is one rectangular cross-section. Similarly, the cross-sectional shape of the light beam at the position of the second spatial light modulator 35 of the second light traveling along the third illumination light path via the microprism array 31 is also one rectangular cross section.

The light modulated by the second spatial light modulator 35 is reflected by the second reflecting surface 33 b of the reflecting member 33 and guided to the relay optical system 36. Hereinafter, in order to simplify the description, the first spatial light modulator 34 and the second spatial light modulator 35 have the same configuration and are arranged symmetrically with respect to a plane including the optical axis AX and parallel to the XY plane. It is assumed that Therefore, the description which overlaps with the 1st spatial light modulator 34 about the 2nd spatial light modulator 35 is abbreviate | omitted, paying attention to the 1st spatial light modulator 34, and the spatial

light modulators

34 and 35 in the spatial light modulation unit 3 The operation of will be described.

As shown in FIGS. 2 and 6, the first spatial light modulator 34 includes a plurality of mirror elements 34a arranged two-dimensionally, a base 34b holding the plurality of mirror elements 34a, and a plurality of mirror elements 34a. A cover glass (cover substrate; not shown in FIG. 6) 34c, and a drive unit 34d that individually controls and drives the postures of the plurality of mirror elements 34a via a cable (not shown) connected to the base 34b. I have. In FIG. 6, for the sake of clarity, the incident angle of light on the first reflecting surface 33a is set to be considerably larger than the incident angle in FIG.

As shown in FIG. 7, the spatial light modulator 34 includes a plurality of minute mirror elements (optical elements) 34 a arranged in a two-dimensional manner, and is incident along the second illumination optical path defined by the optical axis AX1. The emitted light is variably given spatial modulation according to the incident position and emitted. For ease of explanation and illustration, FIGS. 6 and 7 show a configuration example in which the spatial light modulator 34 includes 4 × 4 = 16 mirror elements 34a. Are provided with a number of mirror elements 34a.

Referring to FIG. 6, among the light beams incident on the spatial light modulator 34 along the direction parallel to the optical axis AX1, the light beam L1 is the mirror element SEa of the plurality of mirror elements 34a, and the light beam L2 is the mirror element. The light is incident on a mirror element SEb different from SEa. Similarly, the light beam L3 is incident on a mirror element SEc different from the mirror elements SEa and SEb, and the light beam L4 is incident on a mirror element SEd different from the mirror elements SEa to SEc. The mirror elements SEa to SEd give spatial modulations set according to their positions to the lights L1 to L4.

In the spatial light modulator 34, in a reference state (hereinafter referred to as “reference state”) in which the reflecting surfaces of all the mirror elements 34a are set along one plane, the light enters the direction parallel to the optical axis AX1. The reflected light beam is reflected by the spatial light modulator 34 and then reflected by the first reflecting surface 33a in a direction parallel to the optical axis AX. The surface on which the plurality of mirror elements 34 a of the spatial light modulator 34 are arranged is positioned at or near the front focal position of the relay optical system 36, and thus optically conjugate with the front focal position of the afocal lens 4. Positioned at or near the position.

Therefore, the light reflected by the plurality of mirror elements SEa to SEd of the spatial light modulator 34 and given a predetermined angular distribution is the position of the pupil plane 36c of the relay optical system 36 (position where the aperture stop 37 is installed). Predetermined light intensity distributions SP1 to SP4 are formed, and as a result, light intensity distributions corresponding to the light intensity distributions SP1 to SP4 are formed at the position of the pupil plane 4c of the afocal lens 4. That is, the front lens group 36a of the relay optical system 36 determines the angle that the plurality of mirror elements SEa to SEd of the spatial light modulator 34 gives to the emitted light in the far field region (Fraunhofer diffraction region) of the spatial light modulator 34. The position is converted into a position on a certain surface 36c (and eventually the pupil surface 4c). Similarly, the light reflected by the plurality of mirror elements of the spatial light modulator 35 and given a predetermined angular distribution also forms a predetermined light intensity distribution at the position of the pupil plane 4 c of the afocal lens 4.

Referring to FIG. 1, the incident surface of the cylindrical micro fly's eye lens 8 is positioned at or near a position optically conjugate with the pupil plane 4c (not shown in FIG. 1) of the afocal lens 4. Therefore, the light intensity distribution (illumination pupil luminance distribution) of the secondary light source formed by the cylindrical micro fly's eye lens 8 is formed on the pupil plane 36c by the first spatial light modulator 34 and the front lens group 36a of the relay optical system 36. The distribution corresponds to a combined distribution of the first light intensity distribution and the second light intensity distribution formed on the pupil plane 36c by the front lens group 36a of the second spatial light modulator 35 and the relay optical system 36.

As shown in FIG. 7, the spatial light modulator 34 (35) has a large number of minute reflections regularly and two-dimensionally arranged along one plane with the planar reflection surface as the upper surface. This is a movable multi-mirror including a mirror element 34a (35a) as an element. Each mirror element 34a (35a) is movable, and the inclination of the reflection surface thereof, that is, the inclination angle and the inclination direction of the reflection surface is an action of the drive unit 34d (35d) that operates according to a command from a control unit (not shown). Controlled independently. Each mirror element 34a (35a) can be rotated continuously or discretely by a desired rotation angle, with two directions parallel to the reflecting surface and perpendicular to each other. That is, it is possible to two-dimensionally control the inclination of the reflecting surface of each mirror element 34a (35a).

When the reflecting surface of each mirror element 34a (35a) is discretely rotated, the rotation angle is set in a plurality of states (for example,..., -2.5 degrees, -2.0 degrees,... 0 degrees). , +0.5 degrees,... +2.5 degrees,. Although FIG. 7 shows the mirror element 34a (35a) having a square outer shape, the outer shape of the mirror element 34a (35a) is not limited to a square. However, from the viewpoint of light utilization efficiency, it is possible to provide a shape that can be arranged (a shape that can be packed closest) so that the gap between the mirror elements 34a (35a) is reduced. Further, from the viewpoint of light utilization efficiency, the interval between two adjacent mirror elements 34a (35a) can be minimized.

In the present embodiment, as the spatial

light modulators

34 and 35, for example, spatial light modulators that continuously change the directions of a plurality of mirror elements 34a (35a) arranged two-dimensionally are used. As such a spatial light modulator, for example, Japanese Patent Laid-Open No. 10-503300 and corresponding European Patent Publication No. 779530, Japanese Patent Application Laid-Open No. 2004-78136, and corresponding US Pat. No. 6,900, The spatial light modulator disclosed in Japanese Patent No. 915, Japanese National Publication No. 2006-524349 and US Pat. No. 7,095,546 corresponding thereto, and Japanese Patent Application Laid-Open No. 2006-113437 can be used. Note that the directions of the plurality of mirror elements 34a (35a) arranged two-dimensionally may be controlled so as to have a plurality of discrete stages.

Thus, in the first spatial light modulator 34, the posture of the plurality of mirror elements 34a is changed by the action of the drive unit 34d that operates according to the control signal from the control unit, and each mirror element 34a has a predetermined orientation. Set to As shown in FIG. 8, the light reflected by the plurality of mirror elements 34a of the first spatial light modulator 34 at a predetermined angle is applied to the pupil plane 36c of the relay optical system 36, for example, around the optical axis AX. Two circular

light intensity distributions

41a and 41b spaced apart in the direction are formed.

Similarly, in the second spatial light modulator 35, the posture of the plurality of mirror elements 35a is changed by the action of the drive unit 35b that operates in response to a control signal from the control unit, and each mirror element 35a has a predetermined value. Set to orientation. As shown in FIG. 8, the light reflected by the plurality of mirror elements 35a of the second spatial light modulator 35 at a predetermined angle is applied to the pupil plane 36c of the relay optical system 36, for example, around the optical axis AX. Two circular

light intensity distributions

41c and 41d spaced apart in the direction are formed.

An aperture stop 37 that is replaceable with respect to the first illumination optical path is disposed on or near the pupil plane 36c of the relay optical system 36. When the quadrupole light intensity distribution 41 is formed on the pupil plane 36c of the relay optical system 36, the aperture stop 37 installed in the first illumination optical path has a quadrupole opening (light transmission portion). The aperture stop 37 is configured to be detachable with respect to the illumination optical path, and is configured to be switchable between a plurality of aperture stops having openings 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 aperture stop 37 is disposed at a position optically conjugate with the entrance pupil plane of the projection optical system PL, as in the above-described aperture stop 9, and defines a range that contributes to the illumination of the secondary light source.

The light forming the quadrupolar light intensity distribution 41 on the pupil surface 36c of the relay optical system 36 or the light forming the light intensity distribution 41 is limited by the aperture stop 37, and then the pupil surface of the afocal lens 4 and the cylindrical 4 corresponding to the light intensity distributions 41a to 41d on the entrance plane of the micro fly's eye lens 8 and the illumination pupil (position where the aperture stop 9 is disposed) on the rear focal plane of the cylindrical micro fly's eye lens 8 or in the vicinity thereof. A polar light intensity distribution is formed. Furthermore, the light intensity is also applied to another illumination pupil position optically conjugate with the aperture stop 9, that is, the pupil position of the imaging optical system 12 and the pupil position of the projection optical system PL (position where the aperture stop AS is disposed). A quadrupole light intensity distribution corresponding to the distributions 41a to 41d is formed.

In the exposure apparatus, in order to transfer the pattern of the mask M onto the wafer W with high accuracy and faithfully, it is important to perform exposure under appropriate illumination conditions according to the pattern characteristics. In the present embodiment, a plurality of diffractive optical elements 32 that have different characteristics and can be selectively installed in the illumination light path are provided as means for fixedly forming a light intensity distribution on the illumination pupil. Accordingly, a diffractive optical element for annular illumination that forms a ring-shaped illumination pupil luminance distribution in a fixed manner, a diffractive optical element for multi-pole illumination that forms a fixed illumination pupil luminance distribution in a multiple pole, etc. are selected. By setting only one diffractive optical element 32 in the illumination optical path, the illumination pupil luminance distribution (and thus the illumination condition) can be discretely changed.

Further, in the present embodiment, as means for variably forming the light intensity distribution on the illumination pupil, a pair of spatial

light modulators

34 and 35 in which the postures of the plurality of

mirror elements

34a and 35a individually change are provided. . Therefore, the first light intensity distribution formed on the illumination pupil by the action of the first spatial light modulator 34 and the second light intensity distribution formed on the illumination pupil by the action of the second spatial light modulator 35 can be freely set. Can change quickly. That is, an illumination pupil composed of a first light intensity distribution formed on the illumination pupil by the action of the first spatial light modulator 34 and a second light intensity distribution formed on the illumination pupil by the action of the second spatial light modulator 35. The luminance distribution can be changed freely and quickly.

As described above, in the illumination optical system (2 to 12) of the present embodiment that illuminates the mask M as the irradiated surface based on the light from the light source 1, the diffractive optical element that discretely changes the illumination pupil luminance distribution. 32 and the spatial

light modulators

34 and 35 that change the illumination pupil luminance distribution freely and quickly are configured to be switchable with respect to the illumination optical path, so that the shape and size of the illumination pupil luminance distribution can be varied. Abundant lighting conditions can be realized. Further, in the exposure apparatus (2 to WS) of the present embodiment, the illumination optical system (2 to 12) that realizes a wide variety of illumination conditions is used, and is appropriately realized according to the pattern characteristics of the mask M. Good exposure can be performed under various illumination conditions.

In the present embodiment, the microprism array 31 includes an optical axis AX that defines the first illumination optical path, an optical axis AX1 that defines the second illumination optical path, and an optical axis AX2 that defines the third illumination optical path ( It is configured to be movable in a direction intersecting the (YZ plane), that is, a normal direction (X direction) of the YZ plane. As a result, it is possible to realize a configuration in which the insertion / removal mechanism (exchange mechanism) of the diffractive optical element 32 and the movement space of the microprism array 31 do not interfere with each other without increasing the movement stroke of the microprism array 31. In particular, in the present embodiment, the microprism array 31 and the reflection member 33 attached to the frame member 30 are configured to be movable integrally along the X direction, and thus a pair of fixedly installed spaces. A configuration in which the

optical modulators

34 and 35 and the moving space of the frame member 30 do not interfere with each other can be easily realized.

In the present embodiment, an extension surface of the installation surface (an array surface of the plurality of mirror elements 34a) on which the light modulation surface of the spatial light modulator 34 is located, and an installation surface on which the light modulation surface of the spatial light modulator 35 is located. An extended surface of (the array surface of the plurality of mirror elements 35a) intersects the first illumination light path at an acute angle. Here, “the extended surface intersects the first illumination optical path at an acute angle” means that the front side (light source) along the optical axis AX from the intersection of the optical axis AX defining the first illumination optical path and the extended surface. This means that the angle formed by the line segment extending to the side) and the line segment extending from the intersection point to the light modulation surface along the plane including the optical axis AX and perpendicular to the extension surface is an acute angle. With this configuration, the light modulation surfaces of the spatial

light modulators

34 and 35 can be made to be perpendicular to the optical axes AX1 and AX2, so that the

mirror elements

34a and 35a in the spatial

light modulators

34 and 35 are disposed on the emission side. The aspect ratio of the

mirror elements

34a and 35a of the spatial light modulator is not compressed or expanded when viewed from the optical system located at the position.

In the present embodiment, as described above, the first illumination optical path defined by the optical axis AX and the second illumination optical path defined by the optical axis AX1 intersect at an acute angle, and the first illumination optical path and the light It intersects with the third illumination optical path defined by the axis AX2 at an acute angle. This configuration provides the advantage that the aspect ratio of each

mirror element

34a, 35a of the spatial light modulator is not compressed or expanded as described above. In the present embodiment, the position where the extension surface of the installation surface where the light modulation surface of the spatial light modulator 34 is located and the extension surface of the installation surface where the light modulation surface of the spatial light modulator 35 intersects is This is the exit side of the reflecting member 33 in one illumination optical path. With this configuration, there is an advantage that a space for moving the reflecting member 33 that can be regarded as the second light guide member can be secured.

In the present embodiment, the incident light is split into two lights by the microprism array 31, one light is guided to the first spatial light modulator 34, and the other light is guided to the second spatial light modulator 35. A configuration, that is, a configuration in which a plurality of spatial light modulators are used simultaneously is adopted. With this configuration, the energy density of incident light on the plurality of mirror elements (optical elements) 34a and 35a of the spatial

light modulators

34 and 35 is reduced, and the number of wavefront divisions in the spatial

light modulators

34 and 35 is increased. Thus, the illumination pupil luminance distribution unevenness can be reduced.

In the present embodiment, the first illumination optical path defined by the optical axis AX that is the reference optical axis extends linearly at the position where the microprism array 31 is inserted. In addition, a linearly extended first illumination light path is located between the second illumination light path defined by the optical axis AX1 and the third illumination light path defined by the optical axis AX2. Further, the first illumination light path is extended linearly between the position where the microprism array 31 is inserted and the position where the reflecting member 33 is inserted. With the above-described configurations, the spatial

light modulators

34 and 35 can be added without significantly modifying the configuration of the existing illumination optical system.

By the way, when ArF excimer laser light or KrF excimer laser light is used as exposure light, the optical path is filled with an inert gas such as nitrogen gas or helium gas, which is a gas having a low exposure light absorption rate, or the optical path is changed. It is necessary to maintain a substantially vacuum state. In the present embodiment, since the pair of spatial

light modulators

34 and 35 are fixedly installed, the purge wall 13 including the

cover glasses

34c and 35c can be provided as shown by a broken line in FIG. In this case, since the main body portion (portion including the movable portion) of the spatial

light modulators

34 and 35 is disposed outside the airtight space, the spatial

light modulators

34 and 35 can be freely operated while maintaining good purge. Is possible.

Although the spatial

light modulators

34 and 35 can be configured to be movable, in this case, not only is it difficult to maintain the purge, but the cables extending from the

boards

34b and 35b are accompanied by the movement. And is susceptible to damage. At this time, a cover glass (purge window) may be provided on the purge wall 13 separately from the

cover glasses

34c and 35c attached to the main body portions of the spatial

light modulators

34 and 35. At this time, the light incident on and emitted from the spatial

light modulators

34 and 35 passes through the two cover glasses, but the space is maintained in the state where the purge space where the first and second light guide members are located is maintained. The

light modulators

34 and 35 can be exchanged.

In the present embodiment described above, the first light intensity distribution by the first spatial light modulator 34 and the second light intensity distribution by the second spatial light modulator 35 are formed at different locations in the illumination pupil. The first light intensity distribution and the second light intensity distribution may partially overlap each other, or may be completely overlapped (the first light intensity distribution and the second light intensity distribution are formed in the same distribution and at the same position. ) You may. In the above-described embodiment, the microprism array 31 is used as a dividing member that divides the incident light along the first illumination optical path (along the optical axis AX) into two lights that travel in two different directions. ing. However, the number of divisions of light is not limited to 2, and incident light can be divided into three or more lights using, for example, a diffractive optical element. In general, the light incident along the first illumination optical path can be divided into a plurality of lights traveling in a plurality of different directions, and the same number of spatial light modulators as the number of the divided lights can be provided. In the configuration of the above-described embodiment, a configuration using only one of the pair of spatial

light modulators

34 and 35 is also possible. In this case, for example, a declination prism can be used as a light guide member that guides light incident along the first illumination optical path to the second illumination optical path, instead of the microprism array 31 as the split member.

Further, as an example of the spatial light modulation unit 3 using a single spatial light modulator, the configuration shown in FIG. 9 is possible. The spatial light modulation unit 3 according to the modification of FIG. 9 can be installed at a predetermined position in the first illumination optical path along the optical axis AX, and deflects light incident along the first illumination optical path by, for example, 90 degrees. And a plurality of diffractive optical elements 32 that can be selectively installed at a position in the first illumination light path that is substantially the same as the installation position of the flat mirror 51, for example. Yes. The light reflected in the Z direction by the plane mirror 51 is incident on the spatial light modulator 34 fixedly installed at a predetermined position in the second illumination optical path defined by the optical axis AX3. The light modulated by the spatial light modulator 34 and reflected in the Y direction, for example, is fixedly installed in the second illumination optical path via the relay lens 52 fixedly installed in the second illumination optical path. Incident on the plane mirror 53. The light reflected by the flat mirror 53 in the Z direction, for example, can be set at a predetermined position in the first illumination optical path, that is, at a predetermined position between the front lens group 36a of the relay optical system 36 and the aperture stop 37. Is incident on. The light reflected in the Y direction by the plane mirror 54 enters the aperture stop 37 along the first illumination optical path. As described above, in the spatial light modulation unit 3 according to the modification of FIG. 9, when the single spatial light modulator 34 is used, the plane mirror 51 as the first light guide member includes the shaping optical system 2 and the relay optical system 36. The plane mirror 54 as the second light guide member is disposed on the rear side (irradiated surface side) of the relay lens system 36 with respect to the front lens group 36a. It arrange | positions in one illumination optical path. 9, the light modulated by the spatial light modulator 34 passes through the relay lens 52 and the plane mirrors 53 and 54 having optical characteristics corresponding to the front lens group 36a of the relay optical system 36. A required light intensity distribution is variably formed at the position of the aperture stop 37 (and hence at the position of the illumination pupil). In the modification of FIG. 9, the spatial light modulator 34, the relay lens 52, and the plane mirror 53 are arranged in the order of incidence of light from the plane mirror 51. However, the present invention is not limited to this, and the plane mirror 53 is disposed at the position of the spatial light modulator 34 in FIG. 9, the spatial light modulator 34 is disposed at the position of the plane mirror 53 in FIG. A relay lens 52 may be disposed in the optical path between the

mirrors

53 and 54.

Further, as an example in which the pyramid prism 61 is used as a dividing member that divides incident light along the first illumination optical path (along the optical axis AX) into four light beams that travel in four different directions, the configuration shown in FIG. Is possible. The spatial light modulation unit 3 according to the modified example of FIG. 10 includes a pyramid prism 61 having a quadrangular pyramid shape that is formed of a light transmissive member and has a vertex directed toward the light incident side. The pyramid prism 61 that can be regarded as the divided member can be inserted into and removed from the illumination optical path along the X direction in the drawing. The light incident on the first illumination optical path (along the optical axis AX) is divided into four lights traveling in four different directions by the pyramid prism 61. The four divided lights are incident on four spatial

light modulators

34, 35, 62, and 63 arranged in each illumination light path. The light modulated by each of the spatial

light modulators

34, 35, 62, and 63 is directed to a pyramid mirror 64 having a pyramid shape whose slope is formed on the reflection surface and the apex is directed to the exit side. The pyramid mirror 64 is also configured to be able to be inserted into and removed from the illumination optical path integrally with the pyramid prism 61. Light from each of the spatial

light modulators

34, 35, 62, 63 via the pyramid mirror 64 travels to the front lens group 36 a of the relay optical system 36. Then, although not shown in FIG. 10, a predetermined light intensity distribution is formed at the position of the pupil plane of the illumination optical system as in the above-described embodiment.

Further, as an example using a V-shaped prism as the dividing member, the configuration shown in FIG. 11 is possible. The spatial light modulation unit 3 according to the modified example of FIG. 11 includes a V-shaped prism 65 with a ridge line along the X direction facing the incident side, instead of the microprism array 31 of the embodiment shown in FIG. ing. The prism 65 also has a first light traveling along the optical axis AX1 and a second light traveling along the optical axis AX2 along the first illumination optical path (from the direction along the optical axis AX). And are guided to a pair of spatial

light modulators

34 and 35 fixedly installed outside the first illumination light path.

In the embodiment and the modification described above, the afocal lens 4, the conical axicon system 6, and the zoom lens 7 are disposed in the optical path between the spatial light modulation unit 3 and the cylindrical micro fly's eye lens 8. However, the present invention is not limited to this, and instead of these optical members, for example, a condensing optical system that functions as a Fourier transform lens may be disposed. In the above description, as the spatial light modulator having a plurality of optical elements that are two-dimensionally arranged and individually controlled, the direction (angle: inclination) of the two-dimensionally arranged reflecting surfaces is set. An individually controllable spatial light modulator is used. However, the present invention is not limited to this. For example, a spatial light modulator that can individually control the height (position) of a plurality of two-dimensionally arranged reflecting surfaces can be used. As such a spatial light modulator, for example, Japanese Patent Laid-Open No. 6-281869 and US Pat. No. 5,312,513 corresponding thereto, and Japanese Patent Laid-Open No. 2004-520618 and US Pat. The spatial light modulator disclosed in FIG. 1d of Japanese Patent No. 6,885,493 can be used. In these spatial light modulators, by forming a two-dimensional height distribution, an action similar to that of the diffractive surface can be given to incident light. Note that the spatial light modulator having a plurality of two-dimensionally arranged reflection surfaces described above is disclosed in, for example, Japanese Patent Publication No. 2006-513442 and US Pat. No. 6,891,655 corresponding thereto, Modifications may be made in accordance with the disclosure of Japanese Patent Publication No. 2005-524112 and US Patent Publication No. 2005/0095749 corresponding thereto. In the above description, a reflective spatial light modulator having a plurality of mirror elements is used. However, the present invention is not limited to this. For example, transmission disclosed in US Pat. No. 5,229,872 A type of spatial light modulator may be used.

In the above-described embodiment and each modification, when forming the illumination pupil luminance distribution using the spatial light modulation unit, the illumination pupil luminance distribution is measured by the pupil luminance distribution measuring device, and the spatial light is determined according to the measurement result. Each spatial light modulator in the modulation unit may be controlled. Such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-54328, Japanese Patent Application Laid-Open No. 2003-22967, and US Patent Publication No. 2003/0038225 corresponding thereto. 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 Laid-Open No. 2004-304135 and International Patent Publication No. 2006/080285. 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.

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 is preferably 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. 12 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 12, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a substrate of the semiconductor device (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the projection 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 wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred (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 projection exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. It is. 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 projection 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. 13 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 13, 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 projection exposure apparatus of the above-described embodiment. The pattern forming step includes an exposure step of transferring the pattern to the photoresist layer using the projection exposure apparatus of the above-described embodiment, and development of the plate P on which the pattern is transferred, that is, development of the photoresist layer on the glass substrate. 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 process in 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 suitable laser light sources. 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, the present invention is applied to the illumination optical system that illuminates the mask in the exposure apparatus. However, the present invention is not limited to this, and a general illumination surface other than the mask is illuminated. The present invention can also be applied to an illumination optical system.

In the above-described embodiment, the wavefront division type micro fly's eye lens (fly's eye lens) having a plurality of minute lens surfaces is used as the optical integrator. Instead, an internal reflection type optical integrator (typically Specifically, 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 injection end of the rod-type integrator becomes the position of the mask blind 11. When a rod type integrator is used, a position optically conjugate with the position of the aperture stop AS of the projection optical system PL in the 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.

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 Laid-Open No. 6-124873 in a liquid bath, or a stage having a predetermined depth on a stage as disclosed in Japanese Patent Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed. In the above-described embodiment, a so-called polarization illumination method disclosed in US Publication Nos. 2006/0170901 and 2007/0146676 can be applied.

The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention. In addition, each component of the above-described embodiment can be any combination.

Claims

In the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A light beam conversion element that converts a light beam incident along the first illumination light path into a light beam having a predetermined cross section and forms a light intensity distribution in a fixed manner in an illumination pupil in the first illumination light path;
A first light guide member provided so as to be insertable into the first illumination optical path, and guiding light incident along the first illumination optical path to the second illumination optical path;
A spatial light modulator that variably applies spatial modulation to light incident along the second illumination light path through the first light guide member in order to variably form a light intensity distribution in the illumination pupil. When,
A second light guide member that guides light incident along the second illumination light path through the spatial light modulator to the first illumination light path;
The illumination optical system, wherein the first light guide member is movable in a direction intersecting a plane including the first illumination light path and the second illumination light path.
The illumination optical system according to claim 1, wherein the first light guide member is movable in a normal direction of a surface including the first illumination light path and the second illumination light path.
The first light guide member includes a dividing member that divides light incident along the first illumination optical path into a plurality of lights traveling in a plurality of different directions.
The illumination optical system according to claim 1, wherein the spatial light modulator includes a plurality of spatial light modulators that variably apply spatial modulation to the plurality of lights.
A front optical system disposed adjacent to the light source side of the light beam conversion element along the first illumination light path; and adjacent to the irradiated surface side of the light beam conversion element along the first illumination light path. A rear optical system arranged,
When the spatial light modulator is used, the first light guide member and the second light guide member are disposed in the first illumination light path between the front optical system and the rear optical system. The illumination optical system according to claim 3.
3. The illumination optical system according to claim 1, wherein the first light guide member includes a deflection member that deflects light incident along the first illumination optical path and guides the light to the second illumination optical path. 4. .
A front optical system disposed adjacent to the light source side of the light beam conversion element along the first illumination light path; and adjacent to the irradiated surface side of the light beam conversion element along the first illumination light path. A rear optical system arranged,
In using the spatial light modulator, the first light guide member is disposed in the first illumination light path between the front optical system and the rear optical system, and the second light guide member is disposed on the rear side. The illumination optical system according to claim 5, wherein the illumination optical system is disposed in the first illumination optical path closer to the irradiated surface than the optical system.
In the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A light beam conversion element that converts a light beam incident along the first illumination light path into a light beam having a predetermined cross section and forms a light intensity distribution in a fixed manner in an illumination pupil in the first illumination light path;
A first light guide member provided so as to be insertable into the first illumination optical path, and guiding light incident along the first illumination optical path to the second illumination optical path;
A spatial light modulator that variably applies spatial modulation to light incident along the second illumination light path through the first light guide member in order to variably form a light intensity distribution in the illumination pupil. When,
A second light guide member that guides light incident along the second illumination light path through the spatial light modulator to the first illumination light path;
An illumination optical system, wherein an extension surface of an installation surface on which the light modulation surface of the spatial light modulator is located intersects the first illumination light path at an acute angle.
The illumination optical system according to claim 7, wherein the first illumination optical path and the second illumination optical path intersect at an acute angle.
The first light guide member includes a dividing member that divides light incident along the first illumination optical path into a plurality of lights traveling in a plurality of different directions.
The illumination optical system according to claim 7, wherein the spatial light modulator includes a plurality of spatial light modulators that variably apply spatial modulation to the plurality of lights.
The plurality of spatial light modulators include a first spatial light modulator and a second spatial light modulator,
Of the plurality of lights divided by the first light guide member, the light traveling toward the first spatial light modulator travels along the third illumination light path, and the plurality of lights divided by the first light guide member. Of which the light traveling toward the second spatial light modulator travels along the fourth illumination light path,
The illumination optical system according to claim 9, wherein the first illumination light path and the third illumination light path form an acute angle, and the first illumination light path and the fourth illumination light path form an acute angle.
The first illumination light path extends linearly at a position where the first light guide member is inserted,
11. The illumination optical system according to claim 10, wherein the first illumination light path extended linearly is located between the third illumination light path and the fourth illumination light path.
An extension surface of the first installation surface on which the light modulation surface of the first spatial light modulator is located intersects the first illumination light path at an acute angle, and the light modulation surface of the second spatial light modulator is 12. The illumination optical system according to claim 10, wherein an extended surface of the second installation surface positioned intersects the first illumination light path at an acute angle.
The position where the extended surface of the first installation surface intersects with the extended surface of the second installation surface is an exit side of the second light guide member in the first illumination light path. 12. The illumination optical system according to 12.
The illumination optical system according to claim 1, wherein the second light guide member can be inserted into the first illumination optical path.
15. The first illumination light path is linearly extended between a position where the first light guide member is inserted and a position where the second light guide member is inserted. The illumination optical system described.
The illumination optical system according to claim 1, wherein the spatial light modulator is fixedly disposed in the second illumination light path.
The illumination optical system according to any one of claims 1 to 16, wherein the spatial light modulator includes a plurality of optical elements that are two-dimensionally arranged and individually controlled.
The illumination according to claim 17, wherein the spatial light modulator includes a plurality of mirror elements arranged two-dimensionally, and a drive unit that individually controls and drives the postures of the plurality of mirror elements. Optical system.
The illumination optical system according to claim 18, wherein the driving unit continuously or discretely changes directions of the plurality of mirror elements.
The illumination optical system according to claim 18, wherein the spatial light modulator has a cover substrate that covers the plurality of mirror elements.
21. The illumination optical system according to claim 1, wherein the light beam conversion element includes one or a plurality of diffractive optical elements that can be inserted into and removed from the first illumination optical path.
In the spatial light modulation unit used together with the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A splitting member is provided so as to be insertable into the first illumination optical path, and divides the light incident along the first illumination optical path into a plurality of lights traveling in a plurality of different directions, along the first illumination optical path. A first light guide member for guiding incident light to a plurality of second illumination light paths;
In order to variably form a light intensity distribution in the illumination pupil in the first illumination light path, spatial modulation is performed on each of the light incident along the plurality of second illumination light paths via the first light guide member. A plurality of spatial light modulators that variably provide,
A second light guide member that guides light incident along the plurality of second illumination light paths through the plurality of spatial light modulators to the first illumination light path;
The spatial light modulator unit, wherein the plurality of spatial light modulators are fixedly disposed in the plurality of second illumination light paths.
The spatial light modulation unit according to claim 22, wherein the second light guide member is integrally held with the first light guide member.
The spatial light modulation unit according to claim 22 or 23, wherein the spatial light modulator has a plurality of optical elements that are two-dimensionally arranged and individually controlled.
25. The space according to claim 24, wherein the spatial light modulator includes a plurality of mirror elements arranged two-dimensionally, and a drive unit that individually controls and drives the postures of the plurality of mirror elements. Light modulation unit.
The spatial light modulation unit according to claim 25, wherein the driving unit continuously or discretely changes the directions of the plurality of mirror elements.
The plurality of spatial light modulators each include a cover substrate that separates a space on the mirror element side of the spatial light modulator and a space on the first and second light guide members. Item 27. The spatial light modulation unit according to Item 25 or 26.
A spatial light modulation unit according to any one of claims 22 to 27,
An illumination optical system for illuminating a surface to be irradiated based on light from a light source via the spatial light modulation unit.
A light beam conversion element that converts a light beam incident along the first illumination light path into a light beam having a predetermined cross section and forms a light intensity distribution in a fixed manner in an illumination pupil in the first illumination light path; The illumination optical system according to claim 28.
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. 30. The illumination optical system according to any one of 1 to 21, 28, and 29.
31. An exposure apparatus comprising the illumination optical system according to any one of claims 1 to 21 and 28 to 30 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.
An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to claim 31;
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.