WO2009128293A1 - Spatial light modulation unit, lighting optical system, exposure apparatus and method for manufacturing device - Google Patents

Abstract

Disclosed is a spatial light modulation unit that can stably exert a required function over a required period of time. A spatial light modulation unit (3) is used together with a lighting optical system to illuminate an irradiation subject surface in accordance with light from a light source and forms a desired light intensity distribution on a pupil surface of the lighting optical system. The spatial light modulation unit (3) is comprised of first and second spatial light modulators (3a, 3b) that apply a spatial light modulation to incident light and project the modulated incident light with two-dimensionally arranged and individually controlled multiple optical elements; and division light guide members (3c, 3d, 3e, 3f) that divide the incident light into multiple light components, guide first light component out of the multiple light components to the first spatial light modulator while guiding second light component out of the multiple light components to the second spatial light modulator.

Description

Spatial light modulation unit, illumination optical system, exposure apparatus, and device manufacturing method

The present invention relates to a spatial light modulation unit, an illumination optical system, an exposure apparatus, and a device manufacturing method. More specifically, the present invention relates to an illumination optical system suitable for an exposure apparatus for manufacturing 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 illumination distribution on the wafer in order to accurately transfer the fine pattern onto the wafer.

Conventionally, there has been proposed an illumination optical system capable of continuously changing the illumination pupil luminance distribution (and thus the illumination condition) without using a zoom optical system (see Patent Document 1). In the illumination optical system disclosed in Patent Document 1, an incident light beam is generated using a movable multi-mirror configured by a large number of minute mirror elements that are arranged in an array and whose tilt angle and tilt direction are individually driven and controlled. By dividing and deflecting into minute units for each reflecting surface, the cross section of the light beam is converted into a desired shape or a desired size, and thus a desired illumination pupil luminance distribution is realized.

JP 2002-353105 A

In the illumination optical system described in Patent Document 1, since a movable multi-mirror is used, the degree of freedom in changing the shape and size of the illumination pupil luminance distribution is high. However, since the spatial light modulation unit used in this illumination optical system to form the illumination pupil luminance distribution uses a movable multi-mirror as a single spatial light modulator, the light incident on the reflection surface of the mirror element The energy per unit area is relatively large. As a result, the reflectance of the mirror element is likely to decrease with time due to light irradiation, and as a result, it becomes difficult for the spatial light modulation unit to stably perform a required function over a required period.

On the other hand, if the cross section of the incident light beam to the spatial light modulation unit is made large in order to keep the energy per unit area of light incident on the reflecting surface of the mirror element small, the reflection occupied by many mirror elements arranged two-dimensionally The total area of the region increases, and the spatial light modulator increases in size. Increasing the size of the spatial light modulator leads to an increase in the size of optical systems (lenses, prisms, mirrors, etc.) on the incident side and the exit side of the spatial light modulator, which in turn increases the size and cost of the spatial light modulation unit. End up.

The present invention has been made in view of the above-described problems, and an object thereof is to provide a spatial light modulation unit capable of stably exhibiting a required function over a required period. The present invention also provides an illumination optical system capable of realizing a wide variety of illumination conditions for the shape and size of the illumination pupil luminance distribution, using a spatial light modulation unit that stably exhibits a required function. The purpose is to provide. 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-mentioned problem, in the first embodiment of the present invention, a desired light intensity distribution is used on the pupil plane of the illumination optical system, which is used together with an illumination optical system that illuminates the illuminated surface based on light from a light source. A spatial light modulation unit for forming,
A first spatial light modulator that has a plurality of optical elements that are two-dimensionally arranged and individually controlled, and that emits light by applying spatial light modulation to incident light;
A second spatial light modulator that has a plurality of optical elements that are two-dimensionally arranged and individually controlled, and that emits light by applying spatial light modulation to incident light;
The incident light is divided into a plurality of lights, a first light of the plurality of lights is guided to the first spatial light modulator, and a second light of the plurality of lights is modulated by the second spatial light modulation. A spatial light modulation unit is provided that includes a divided light guide member that leads to a vessel.

In the second embodiment of the present invention, in the illumination optical system that illuminates the illuminated surface based on the light from the light source,
A spatial light modulation unit of the first form;
A distribution forming optical system that forms a predetermined light intensity distribution on an illumination pupil of the illumination optical system based on the light that has passed through the first spatial light modulator and the second spatial light modulator. An illumination optical system is provided.

According to a third aspect of the present invention, there is provided an exposure apparatus comprising the illumination optical system according to the second aspect for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.

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

In the present invention, since the spatial light modulation unit includes a pair of spatial light modulators, the light intensity per unit area of the light incident on the optical surface of the optical element is larger than when the spatial light modulator is used alone. Energy can be kept small. Specifically, when a pair of reflective spatial light modulators having a plurality of mirror elements is used, the energy per unit area of light incident on the reflecting surface of the mirror elements can be kept small. As a result, in the spatial light modulation unit of the present invention, the reflectance of the mirror element is not easily lowered even when irradiated with light over a long period of time, and a required function can be stably exhibited over a required period. .

Therefore, in the illumination optical system of the present invention, it is possible to realize a wide variety of illumination conditions for the shape and size of the illumination pupil luminance distribution by using the spatial light modulation unit that stably exhibits the required function. . 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 concerning this embodiment. It is a perspective view which shows roughly the structure of a cylindrical micro fly's eye lens. It is a figure which shows schematically the principal part structure of the spatial light modulation unit of FIG. FIG. 5 is a partial perspective view of the spatial light modulator of FIG. 4. It is a figure which shows typically the light intensity distribution of 4 pole shape formed in the pupil plane of an afocal lens in this embodiment. It is a figure which shows schematically the principal part structure of the modification which uses a prism unit as a light splitter. It is a figure which shows roughly the principal part structure of the modification of the spatial light modulation unit provided with the division | segmentation light guide member which has the form of one prism. It is a figure which shows roughly the principal part structure of another modification of the spatial light modulation unit provided with the division | segmentation light guide member which has the form of one prism. 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 3a, 3b Spatial light modulator 3c Diffraction optical element 3g Prism unit 4 Afocal lens 7 Zoom lens 8 Cylindrical micro fly's eye lens 10 Condenser optical system 11 Mask blind 12 Imaging optical system SE Spatial light modulation Mirror elements 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 an internal configuration of the spatial light modulation unit according to the present embodiment. 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 includes, in order from the light incident side, a diffractive optical element 3c, a condenser lens 3d, a pair of prisms 3e and 3f, and a pair of spatial light modulators 3a and 3b. And. The specific configuration and operation of the spatial light modulation unit 3 will be described later.

Referring to FIG. 1 again, the light emitted from the spatial light modulation unit 3 enters the afocal lens 4. The afocal lens 4 is an afocal system (non-focal optical system), its front focal position, the position of the first spatial light modulator 3a in the spatial light modulation unit 3, and the position of the second spatial light modulator 3b. Are substantially matched with each other, and the rear focal position is substantially matched with the position of the predetermined surface 5 indicated by a broken line in the figure.

Therefore, the light passing through the first spatial light modulator 3a is, for example, in the Z direction formed of two circular light intensity distributions spaced apart in the Z direction about the optical axis AX on the pupil plane of the afocal lens 4. After forming a dipolar light intensity distribution, the light is emitted from the afocal lens 4 with a dipolar angular distribution. On the other hand, the light that has passed through the second spatial light modulator 3b is, on the pupil plane of the afocal lens 4, for example, an X direction composed of two circular light intensity distributions spaced apart in the X direction about the optical axis AX. After forming a dipolar light intensity distribution, the light is emitted from the afocal lens 4 with a dipolar angular distribution.

In the optical path between the front lens group 4a and the rear lens group 4b of the afocal lens 4, the position of the pupil plane (the position indicated by reference numeral 4c in FIG. 2) or a position in the vicinity thereof has a conical axicon system 6 Is arranged. 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.

Accordingly, on the incident surface of the cylindrical micro fly's eye lens 8, as with the pupil surface of the afocal lens 4, for example, two circular light intensity distributions and light with an interval in the Z direction centered on the optical axis AX. A quadrupole illumination field is formed which consists of two circular light intensity distributions spaced apart in the X direction about the axis AX. The overall shape of this quadrupole 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. The next light source, that is, two circular substantial surface light sources spaced in the Z direction around the optical axis AX and two circular substantial surfaces spaced in the X direction around the optical axis AX A quadrupole secondary light source (a quadrupole illumination pupil luminance distribution) composed of a light source 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 a quadrupole opening (light transmission portion) corresponding to a quadrupolar 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 focusing on a quadrupolar or annular secondary light source.

In a state where 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 plane parallel plate and is formed as a four-pole. There is no effect on the secondary light source in the form of a ring or ring. However, when 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 quadrupolar or annular secondary light source (the quadrupolar secondary light source). 1/2 of the difference between the diameter (outer diameter) of the circle circumscribing the light source and the diameter (inner diameter) of the inscribed circle; 1/2 of the difference between the outer diameter and inner diameter of the annular secondary light source The outer diameter (inner diameter) of the quadrupole or ring-shaped secondary light source changes while maintaining. That is, the annular ratio (inner diameter / outer diameter) and size (outer diameter) of the quadrupolar or annular secondary light source change.

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

In the spatial light modulation unit 3 of the present embodiment, as shown in FIG. 2, the light beam from the light source 1 via the shaping optical system 2 enters the diffractive optical element 3c 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 3c is spaced from the far field (or Fraunhofer diffraction region) in the Z direction with the optical axis AX as the center. It has a function of forming two rectangular light intensity distributions.

The first light beam of the two light beams divided by the diffractive optical element 3c passes through the condensing lens 3d functioning as a Fourier transform lens, passes through the prism 3e and the first spatial light modulator 3a, and is then an afocal lens. 4 reaches the pupil plane 4c of the afocal lens 4 via the front lens group 4a. On the other hand, the second light beam of the two light beams divided by the diffractive optical element 3c passes through the condenser lens 3d, passes through the prism 3f and the second spatial light modulator 3b, and then passes through the front lens group 4a. It reaches the pupil plane 4c. The front lens group 4a of the afocal lens 4 superimposes the light beam via the first spatial light modulator 3a and the light beam via the second spatial light modulator 3b on the pupil plane 4c.

Hereinafter, in order to facilitate the understanding of the description, a first optical unit (3e, 3a) comprising a prism 3e and a first spatial light modulator 3a, a first optical unit comprising a prism 3f and a second spatial light modulator 3b. The two optical units (3f, 3b) have the same configuration and are arranged symmetrically with respect to a plane including the optical axis AX and parallel to the XY plane. Therefore, the description which overlaps with the 1st optical unit (3e, 3a) about the 2nd optical unit (3f, 3b) is abbreviate | omitted, paying attention to the 1st optical unit (3e, 3a), the concrete of the spatial light modulation unit 3 A typical configuration and operation will be described.

As shown in FIG. 4, the first optical unit (3e, 3a) is attached close to a prism 3e formed of an optical material such as fluorite and a side surface 3ea parallel to the XY plane of the prism 3e. And a reflective spatial light modulator 3a. The optical material forming the prism 3e is not limited to fluorite, and may be quartz glass or other optical material according to the wavelength of light supplied from the light source 1 or the like. The spatial light modulator 3a includes a main body 3aa having a plurality of mirror elements SE arranged two-dimensionally, and a drive unit 3ab for individually controlling and driving the postures of the plurality of mirror elements SE.

The prism 3e has a form obtained by replacing one side surface of the rectangular parallelepiped (the side surface facing the side surface 3ea to which the main body 3aa of the spatial light modulator 3a is attached) with the side surfaces 3eb and 3ec recessed in a V shape. It is also called a K prism because of its cross-sectional shape along the YZ plane. Sides 3eb and 3ec that are concave in a V shape of the prism 3e are defined by two planes PN1 and PN2 that intersect to form an obtuse angle. The two planes PN1 and PN2 are both orthogonal to the YZ plane and have a V shape along the YZ plane.

The inner surfaces of the two side surfaces 3eb and 3ec that are in contact with the tangent lines (straight lines extending in the X direction) P3 between the two planes PN1 and PN2 function as reflecting surfaces R1a and R2a. That is, the reflective surface R1a is located on the plane PN1, the reflective surface R2a is located on the plane PN2, and the angle formed by the reflective surfaces R1a and R2a is an obtuse angle. As an example, the angle between the reflecting surfaces R1a and R2a is 120 degrees, the angle between the incident surface IP of the prism 3e perpendicular to the optical axis AXa and the reflecting surface R1a is 60 degrees, and the prism 3e perpendicular to the optical axis AXa. The angle formed by the exit surface OP and the reflecting surface R2a can be 60 degrees.

In the prism 3e, the side surface 3ea to which the main body 3aa of the spatial light modulator 3a is attached is parallel to the optical axis AXa, and the reflection surface R1a is on the light source 1 side (upstream side of the exposure apparatus: left side in FIG. 4). Further, the reflection surface R2a is located on the afocal lens 4 side (downstream side of the exposure apparatus: right side in FIG. 4). More specifically, the reflective surface R1a is obliquely arranged with respect to the optical axis AXa, and the reflective surface R2a is obliquely symmetrical with respect to the optical axis AXa symmetrically with the reflective surface R1a with respect to a plane passing through the tangent line P3 and parallel to the XZ plane. It is installed. As will be described later, the side surface 3ea of the prism 3e is an optical surface facing the surface on which the plurality of mirror elements SE are arranged in the main body 3aa of the spatial light modulator 3a.

The reflecting surface R1a of the prism 3e reflects the light incident through the incident surface IP toward the spatial light modulator 3a. The spatial light modulator 3a is disposed in the optical path between the reflecting surface R1a and the reflecting surface R2a, and reflects the light incident through the reflecting surface R1a. The reflecting surface R2a of the prism 3e reflects the light incident through the spatial light modulator 3a and guides it to the front lens group 4a of the afocal lens 4 through the exit surface OP. In FIG. 4, in order to facilitate understanding of the description, the optical path is developed so that the optical axis AXa extends linearly on the rear side of the front lens group 4a. 4 shows an example in which the prism 3e is integrally formed by one optical block, the prism 3e may be configured by using a plurality of optical blocks.

The spatial light modulator 3a emits the light incident through the reflecting surface R1a with spatial modulation according to the incident position. As shown in FIG. 5, the main body 3aa of the spatial light modulator 3a includes a plurality of minute mirror elements (optical elements) SE arranged two-dimensionally. For ease of explanation and illustration, FIG. 4 and FIG. 5 show a configuration example in which the spatial light modulator 3a includes 4 × 4 = 16 mirror elements SE. Are provided with a number of mirror elements SE.

Referring to FIG. 4, among the light beams incident on the prism 3 e along the direction parallel to the optical axis AXa, the light beam L1 is the mirror element SEa of the plurality of mirror elements SE, and the light beam L2 is the mirror element SEa. Each incident on a different mirror element SEb. 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 3a, in the reference state (hereinafter referred to as “reference state”) in which the reflection surfaces of all the mirror elements SE are set parallel to the XY plane, the reflection surfaces along the direction parallel to the optical axis AXa. The light beam incident on R1a passes through the spatial light modulator 3a, and is then reflected by the reflecting surface R2a in a direction parallel to the optical axis AXa. The spatial light modulator 3a corresponds to the air conversion length from the incident surface IP of the prism 3e to the exit surface OP through the mirror elements SEa to SEd, and the incident surface IP when the prism 3e is not disposed in the optical path. The air-converted length from the position to the position corresponding to the exit surface OP is configured to be equal. Here, the air conversion length is the optical path length in the optical system converted into the optical path length in the air with a refractive index of 1, and the air conversion length in the medium with the refractive index n is 1 / the optical path length. multiplied by n. The optical path length from the spatial light modulator 3a to the reflection surface R2a is equal to the optical path length from the spatial light modulator 3b to the reflection surface R2b.

The surface on which the plurality of mirror elements SE of the spatial light modulator 3a are arranged is positioned at or near the rear focal position of the condenser lens 3d, and is positioned at or near the front focal position of the afocal lens 4. Yes. Accordingly, a light beam having a cross section having a shape (for example, a rectangular shape) corresponding to the characteristics of the diffractive optical element 3c is incident on the spatial light modulator 3a. The light reflected by the plurality of mirror elements SEa to SEd of the spatial light modulator 3a and given a predetermined angular distribution forms predetermined light intensity distributions SP1 to SP4 on the pupil plane 4c of the afocal lens 4. That is, the front lens group 4a of the afocal lens 4 determines the angle that the plurality of mirror elements SEa to SEd of the spatial light modulator 3a gives to the emitted light in the far field region (Fraunhofer diffraction region) of the spatial light modulator 3a. The position is converted to a position on a certain surface 4c.

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 (luminance distribution) of the secondary light source formed by the cylindrical micro fly's eye lens 8 is the light intensity distribution SP1 formed on the pupil plane 4c by the spatial light modulator 3a and the front lens group 4a of the afocal lens 4. Distribution according to SP4. As shown in FIG. 5, the spatial light modulator 3 a is a large number of minute reflective elements that are regularly and two-dimensionally arranged along one plane with a planar reflective surface as the upper surface. A movable multi-mirror including a mirror element SE.

Each mirror element SE is movable, and the inclination of the reflection surface, that is, the inclination angle and the inclination direction of the reflection surface are independently controlled by the action of the drive unit 3ab that operates according to a command from a control unit (not shown). . Each mirror element SE can be rotated continuously or discretely by a desired rotation angle with two directions (X direction and Y direction) parallel to the reflecting surface and orthogonal to each other as rotation axes. . That is, it is possible to two-dimensionally control the inclination of the reflection surface of each mirror element SE.

In addition, when the reflection surface of each mirror element SE is discretely rotated, the rotation angle is set in a plurality of states (for example,..., −2.5 degrees, −2.0 degrees,... 0 degrees, +0. It is better to perform switching control at 5 degrees... +2.5 degrees,. Although FIG. 5 shows a mirror element SE having a square outer shape, the outer shape of the mirror element SE 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 so as to reduce the gap between the mirror elements SE (a shape that can be closely packed). Further, from the viewpoint of light utilization efficiency, the interval between two adjacent mirror elements SE can be minimized.

In this embodiment, as the spatial light modulators 3a and 3b, for example, spatial light modulators that continuously change the directions of a plurality of mirror elements SE 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 SE arranged two-dimensionally may be controlled so as to have a plurality of stages discretely.

Thus, in the first spatial light modulator 3a, the attitude of the plurality of mirror elements SE is changed by the action of the drive unit 3ab that operates according to the control signal from the control unit, and each mirror element SE is in a predetermined direction. Set to As shown in FIG. 6, the light reflected by the plurality of mirror elements SE of the first spatial light modulator 3 a at a predetermined angle is applied to the pupil surface of the afocal lens 4, for example, in the Z direction centering on the optical axis AX. Two circular light intensity distributions 41a and 41b spaced apart from each other are formed.

Similarly, in the second spatial light modulator 3b, the posture of the plurality of mirror elements SE of the main body 3ba is changed by the action of the drive unit 3bb that operates according to the control signal from the control unit, and each mirror element SE is changed. Each is set in a predetermined direction. As shown in FIG. 6, the light reflected by the plurality of mirror elements SE of the second spatial light modulator 3b at a predetermined angle is applied to the pupil plane of the afocal lens 4, for example, in the X direction with the optical axis AX as the center. Two circular light intensity distributions 41c and 41d are formed at a distance from each other.

In the present embodiment, the reflecting surface R1a is obliquely arranged at a first angle with respect to the optical axis AXa, and the reflecting surface R1b is a second angle having the same size as the first angle with respect to the optical axis AXa. It is obliquely installed.

In this embodiment, since the optical path length from the spatial light modulator 3a to the reflecting surface R2a and the optical path length from the spatial light modulator 3b to the reflecting surface R2b are equal to each other, from the pupil surface 4c of the afocal lens 4 The optical path lengths to the spatial light modulators 3a and 3b can be made equal.

The light having a quadrupolar light intensity distribution 41 formed on the pupil plane of the afocal lens 4 is incident on the incident surface of the cylindrical micro fly's eye lens 8 and the illumination pupil at or near the rear focal plane of the cylindrical micro fly's eye lens 8. A quadrupole light intensity distribution corresponding to the light intensity distributions 41a to 41d is formed at the position where the aperture stop 9 is disposed. 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.

That is, the afocal lens 4, the zoom lens 7, and the cylindrical micro fly's eye lens 8 are based on the illumination optical system (2 to 12) based on the light flux that has passed through the first spatial light modulator 3a and the second spatial light modulator 3b. The distribution forming optical system that forms a predetermined light intensity distribution on the illumination pupil of (1) is configured. The afocal lens 4 and the zoom lens 7 constitute a condensing optical system disposed in the optical path between the cylindrical micro fly's eye lens 8 serving as an optical integrator and the spatial light modulation unit 3.

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, since the spatial light modulation unit 3 including the pair of spatial light modulators 3a and 3b in which the postures of the plurality of mirror elements SE individually change is used, the operation of the first spatial light modulator 3a is performed. Thus, the first light intensity distribution formed on the illumination pupil and the second light intensity distribution formed on the illumination pupil by the action of the second spatial light modulator 3b can be freely and quickly changed.

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 3a and a second light intensity distribution formed on the illumination pupil by the action of the second spatial light modulator 3b. The luminance distribution can be changed freely and quickly. As a result, in the present embodiment, by changing the shape and size of the first light intensity distribution and the second light intensity distribution, various illumination conditions for the shape and size of the illumination pupil luminance distribution are realized. can do.

Further, in this embodiment, since the spatial light modulation unit 3 including the pair of spatial light modulators 3a and 3b is used, the reflection of the mirror element SE is compared with the case where the spatial light modulator is used alone. The energy per unit area of light incident on the surface is reduced (for example, halved). As a result, in the spatial light modulation unit 3 of the present embodiment, the reflectance of the mirror element SE is unlikely to decrease even when light irradiation is performed over a long period of time, and a required function is stably exhibited over a required period. be able to.

As described above, in the illumination optical system (2 to 12) that illuminates the mask M as the irradiated surface based on the light from the light source 1 in the present embodiment, the spatial light modulation unit that stably exhibits a required function. 3 can be used to realize a variety of illumination conditions for the shape and size of the illumination pupil luminance distribution. 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 particular, in the present embodiment, the arrangement surface where the plurality of mirror elements SE of the first spatial light modulator 3a are arranged and the arrangement surface where the plurality of mirror elements SE of the second spatial light modulator 3b are arranged are parallel. In addition, the reflecting surfaces of the plurality of mirror elements SE of the first spatial light modulator 3a are opposed to the reflecting surfaces of the plurality of mirror elements SE of the second spatial light modulator 3b. With this configuration, the distance between the pair of light beams incident on the pair of prisms 3e and 3f and the distance between the pair of light beams emitted from the pair of prisms 3e and 3f can be reduced. As a result, the optical system (condensing lens 3d, afocal lens 4 and the like) before and after the pair of prisms 3e and 3f can be downsized, and the spatial light modulation unit 3 and the illumination optical system (2 to 12) can be downsized. Can be planned.

In the present embodiment, since the diffractive optical element 3c is used as the light splitter, the uniformity of the intensity of light incident on the spatial light modulators 3a and 3b in the spatial light modulation unit 3 can be improved. There is an advantage. Further, even if the position of the light beam incident on the diffractive optical element 3c changes, the angle of the light beam immediately after the diffractive optical element 3c does not change, so that the position of the light beam incident on the spatial light modulators 3a and 3b hardly changes. There is an advantage.

In the present embodiment, the first light intensity distribution by the first spatial light modulator 3a and the second light intensity distribution by the second spatial light modulator 3b are formed at different locations in the illumination pupil. The 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). May be.

In the above-described embodiment, the diffractive optical element 3c is used as a light splitter that divides incident light into two lights. However, the present invention is not limited to this. For example, as shown in FIG. 7, a configuration in which an incident light beam is divided into two light beams using a prism unit 3g having a pair of prism members 3ga and 3gb is also possible. The modification of FIG. 7 has a configuration similar to that of the embodiment of FIG. 2 except that a prism unit 3g is arranged instead of the diffractive optical element 3c and the condenser lens 3d. 7, elements having the same functions as those shown in FIG. 2 are denoted by the same reference numerals as those in FIG.

The prism unit 3g functioning as a light splitter in the modification of FIG. 7 has, in order from the light source side (left side in the figure), a plane facing the light source side and a concave and V-shaped refraction on the mask side (right side in the figure). The first prism member 3ga having a surface and the second prism member 3gb having a flat surface facing the mask and a convex and V-shaped refracting surface facing the light source. The concave refracting surface of the first prism member 3ga is composed of two planes, and the intersection line (ridge line) extends along the X direction. The convex refracting surface of the second prism member 3gb is formed complementary to the concave refracting surface of the first prism member 3ga. That is, the convex refracting surface of the second prism member 3gb is also composed of two planes, and the line of intersection (ridge line) extends along the X direction. In the modified example of FIG. 7, the prism unit 3g as a light splitter is configured by the pair of prism members 3ga and 3gb. However, the light splitter may be configured by using at least one prism. Furthermore, various forms are possible for the specific configuration of the optical splitter.

In the above-described embodiment and the modification of FIG. 7, the plurality of mirror elements SE of the first spatial light modulator 3a are arranged close to the prism 3e, and the plurality of mirror elements SE of the second spatial light modulator 3b. Is arranged close to the prism 3f. In this case, the prisms 3e and 3f serve as cover members for the plurality of mirror elements SE, and the durability of the spatial light modulators 3a and 3b can be improved.

Further, in the above-described embodiment and the modification of FIG. 7, when a light beam having a rectangular cross section is incident on the diffractive optical element 3 c or the prism unit 3 g, the prisms 3 e and 3 f are reduced in size, and consequently the spatial light modulation unit 3. In order to reduce the size, the incident light beam can be divided in the short side direction of the rectangular cross section. In other words, the incident light beam can be divided in a plane whose normal is the longitudinal direction of the effective regions of the spatial light modulators 3a and 3b in the spatial light modulation unit 3.

Further, in the above-described embodiment and the modification of FIG. 7, the reflecting surface R1a on the incident side of the prism 3e directs the light that has passed through the diffractive optical element 3c or the prism unit 3g as an optical splitter toward the first spatial light modulator 3a. The reflecting surface R1b on the incident side of the prism 3f is a second deflecting surface that deflects the light that has passed through the diffractive optical element 3c or the prism unit 3g toward the second spatial light modulator 3b. It is composed. The diffractive optical element 3c or prism unit 3g, the reflecting surface R1a, and the reflecting surface R1b divide the incident light into two lights (generally a plurality of lights), and the first light is the first spatial light modulator 3a. And a divided light guide member for guiding the second light to the second spatial light modulator 3b.

The reflecting surface R2a on the exit side of the prism 3e constitutes a third deflecting surface that deflects the light that has passed through the first spatial light modulator 3a toward the afocal lens 4 that is the subsequent optical system, and the exit surface of the prism 3f. The reflection surface R2b on the side constitutes a fourth deflection surface that deflects the light having passed through the second spatial light modulator 3b toward the afocal lens 4. The first to fourth deflection surfaces may deflect the light by total reflection at the interface between the prism and the gas, or may deflect the light by the action of a reflection film provided at the interface. Various configurations are possible for the specific configuration of the first deflection surface to the fourth deflection surface, the specific configuration of the divided light guide member, and the specific configuration of the spatial light modulation unit.

Hereinafter, with reference to FIG. 8 and FIG. 9, the structure of the principal part of two modifications of the spatial light modulation unit provided with the divided light guide member having the form of one prism will be described. In the modification of FIG. 8, a prism 3h having a triangular prism shape as a whole and a triangular cross section along the XY plane is used as the divided light guide member. The prism 3h has a pair of side surfaces 3ha and 3hb that are symmetrical with respect to a plane that includes the optical axis AX and is parallel to the XY plane. The side surface 3ha functions as a surface reflecting surface R1a that reflects incident light toward the main body 3aa of the first spatial light modulator 3a, and the side surface 3hb directs incident light toward the main body 3ba of the second spatial light modulator 3b. It functions as a reflective surface R1b that reflects. In the prism 3h, the incident light is divided into two lights along the ridge line between the reflecting surfaces R1a and R1b.

In other words, the prism 3h serving as the divided light guide member has a first deflection surface R1a that deflects the incident light toward the first spatial light modulator 3a and the incident light toward the second spatial light modulator 3b. And deflects incident light into first light and second light along a ridge line between the first deflection surface R1a and the second deflection surface R1b. The light that has passed through the first spatial light modulator 3a is reflected by the reflection surface (third deflection surface) R2a of the planar reflecting mirror 3j and is emitted from the spatial light modulation unit 3. The light that has passed through the second spatial light modulator 3b is reflected by the reflecting surface (fourth deflecting surface) R2b of the planar reflecting mirror 3k and is emitted from the spatial light modulating unit 3.

Here, the first deflection surface R1a is obliquely arranged at a first angle with respect to the optical axis of the illumination optical system, and the second deflection surface R1b has a first angle and size with respect to the optical axis of the illumination optical system. It is inclined at the same second angle. Also in the modification of FIG. 8, the optical path length from the first spatial light modulator 3a to the third deflection surface R2a and the optical path length from the second spatial light modulator 3b to the fourth deflection surface R2b are equal to each other. It has become.

Further, in the modification of FIG. 8, the surface on which the ridgeline of the prism 3 h that can be regarded as a divided light guide member can be used as a light dividing surface that divides incident light into a plurality of lights. A first optical path that reaches the subsequent optical system (for example, the lens 4c) through the first spatial light modulator 3a, and a subsequent optical system (for example, the lens 4c) from this light splitting surface through the second spatial light modulator 3b. A light transmitting member that changes the polarization state of incident light is not disposed in the second optical path that reaches the second optical path. Thereby, the control of the polarization state in the pupil intensity distribution formed on the illumination pupil plane can be made better.

In the modification of FIG. 9, the split light guide member includes a prism 3m having a square columnar cross section along the XY plane. The prism 3m has a pair of side surfaces 3ma and 3mb that are symmetrical with respect to a plane that includes the optical axis AX and is parallel to the XY plane. The side surface 3ma functions as a reflection surface R1a that reflects incident light toward the main body 3aa of the first spatial light modulator 3a, and the side surface 3mb reflects incident light toward the main body 3ba of the second spatial light modulator 3b. Functions as the reflecting surface R1b. In the prism 3m, incident light is divided into two lights along the ridge line between the reflecting surface (first deflecting surface) R1a and the reflecting surface (second deflecting surface) R1b.

The light that has passed through the first spatial light modulator 3a and the second spatial light modulator 3b is incident on prismatic prisms 3n and 3p as illustrated. The side surface 3na of the prism 3n functions as a third deflection surface R2a that deflects the light that has passed through the first spatial light modulator 3a toward the subsequent optical system, and the side surface 3pa of the prism 3p has passed through the second spatial light modulator 3b. It functions as a fourth deflection surface R2b that deflects light toward the subsequent optical system. That is, the light that has passed through the first spatial light modulator 3 a and the second spatial light modulator 3 b is deflected by the third deflection surface R 2 a and the fourth deflection surface R 2 b and is emitted from the spatial light modulation unit 3. In the modification of FIG. 8 and the modification of FIG. 9, various shapes are possible for the shape of the cross section along the XY plane of the prisms 3 h, 3 m, 3 n, and 3 p.

Here, the first deflection surface R1a is obliquely arranged at a first angle with respect to the optical axis of the illumination optical system, and the second deflection surface R1b has a first angle and size with respect to the optical axis of the illumination optical system. It is inclined at the same second angle. Also in the modification of FIG. 9, the optical path length from the first spatial light modulator 3a to the third deflection surface R2a and the optical path length from the second spatial light modulator 3b to the fourth deflection surface R2b are equal to each other. It has become.

In the modification of FIG. 9, the surface on which the ridgeline of the prism 3m that can be regarded as a divided light guide member can be used as a light dividing surface that divides incident light into a plurality of lights. A first optical path that reaches the subsequent optical system (for example, the lens 4c) through the first spatial light modulator 3a, and a subsequent optical system (for example, the lens 4c) from this light splitting surface through the second spatial light modulator 3b. The light transmissive members 3n and 3p arranged in the second optical path to reach are light transmissive members that maintain the polarization state of incident light. Thereby, the control of the polarization state in the pupil intensity distribution formed on the illumination pupil plane can be made better. As such a light transmission member that maintains the polarization state of incident light, for example, quartz glass can be applied.

In the modification shown in FIG. 8 and FIG. 9, a light splitter that divides incident light, a first deflection surface that deflects the divided light toward the first spatial light modulator 3a, and another divided light beam. Since it also serves as the second deflection surface that deflects light toward the second spatial light modulator, there is an advantage that the spatial light modulation unit 3 itself can be made very small. Therefore, when the spatial light modulation unit 3 according to these modifications is incorporated in place of the illumination luminance distribution generation element (for example, diffractive optical element) in the existing exposure apparatus, the modification of the existing exposure apparatus is minimized. Can do.

Also, a spatial light modulation unit may be formed from the pair of prisms 3e and 3f and the pair of spatial light modulators 3a and 3b in the above-described embodiment. In this case, the reflecting surface R1a of the prism 3e and the reflecting surface R1b of the prism 3f can be regarded as a light splitter that divides incident light into first light and second light, and the reflection of the prism 3e. The surface R1a can be regarded as a first deflecting surface that deflects the first light toward the first spatial light modulator 3a, and the reflecting surface R1b of the prism 3f sends the second light to the second spatial light modulator 3b. It can be regarded as a second deflecting surface that deflects toward. In this case, the reflecting surface R2a of the prism 3e can be regarded as a third deflecting surface that deflects the light that has passed through the first spatial light modulator 3a toward the subsequent optical system, and the reflecting surface R2b of the prism 3f is the first reflecting surface R2b. It can be regarded as a fourth deflecting surface that deflects the light that has passed through the two spatial light modulator 3b toward the subsequent optical system.

In this case, the air conversion length from the incident surface IP of the prism 3e (3f) to the exit surface OP through the mirror element of the first spatial light modulator 3a is incident when the prism 3e (3f) is not disposed in the optical path. Since it is configured to be equal to the air-converted length from the surface IP to the position corresponding to the exit surface OP, it is necessary to install an existing illumination intensity distribution generating element (for example, a diffractive optical element) in an existing exposure apparatus. The modification of the exposure apparatus can be minimized, and in particular, the optical system can be made without modification.

In the above-described embodiments and modifications, the first deflection surface R1a or its extension surface and the second deflection surface R1b or its extension surface form an acute angle so that the projection is directed toward the incident light. Is arranged. This configuration enables a compact design of the spatial light modulation unit 3.

In the above-described embodiment and each modification, in the reference state of the spatial light modulators 3a and 3b, the traveling direction of the incident light to the divided light guide members (3c to 3f; 3e to 3g; 3h; 3m); The traveling direction of the emitted light emitted from the third deflection surface R2a and the traveling direction of the emitted light emitted from the fourth deflection surface R2b are configured to be parallel to each other. Further, the traveling direction of the emitted light from the third deflection surface R2a in the reference state and the traveling direction of the emitted light from the fourth deflection surface R2b in the reference state are parallel to the optical axis AX of the illumination optical system (in some cases Match). With this configuration, the optical path is coaxial (in some cases parallel) between the upstream and downstream of the spatial light modulation unit 3, so that, for example, a conventional illumination optical system and optical system using a diffractive optical element to form an illumination pupil luminance distribution. The system can be shared.

Moreover, in the above-mentioned embodiment and each modification, when the spatial light modulation unit 3 is configured to be detachable with respect to the illumination optical path, the cables connected to the main bodies 3a and 3b of the spatial light modulator are smooth. The spatial light modulation unit 3 can be moved not in the Z direction but in the X direction so as not to hinder the insertion / removal operation.

In the above-described embodiment and each modification, 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. Yes. 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.

Further, in the above-described embodiment and each modification, a configuration in which light having different polarization states is incident on the plurality of spatial light modulators 3a and 3b may be employed. In this case, in the embodiment shown in FIG. 2 and the modification shown in FIG. 7, for example, a polarizing optical member may be disposed in the optical path of a pair of light beams incident on the pair of prisms 3e and 3f. Here, the polarizing optical member may be provided on the incident surface IP of the pair of prisms 3e and 3f.

8 and 9, for example, a polarizing optical member may be disposed in the optical path between the prism 3h serving as a divided light guide member and each of the spatial light modulators 3a and 3b. In addition, as the reflection film provided on the reflection surface (the first deflection surface R1a or the second deflection surface R1b) of the prism 3h, a reflection film that gives a phase difference between mutually orthogonal polarization components is applied to each spatial light modulator. You may change the polarization state of the light which goes to 3a, 3b. In this case, a reflective film that gives a phase difference between polarization components orthogonal to each other can be regarded as a polarizing optical member.

As the polarizing optical member described above, a phase member such as a wave plate or an optical rotator, a polarizer, or the like can be used. The polarizing optical member is disposed on at least one of the optical path between the divided light guide member and the first spatial light modulator 3a and the optical path between the divided light guide member and the second spatial light modulator 3b. It only has to be done.

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. 10 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 10, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the 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. 11 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 11, in the manufacturing process of the liquid crystal device, 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 of step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

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

In the above-described embodiment, ArF excimer laser light (wavelength: 193 nm) or KrF excimer laser light (wavelength: 248 nm) is used as the exposure light. However, the present invention is not limited to this, and other appropriate laser light sources are used. For example, the present invention can also be applied to an F ₂ laser light source that supplies laser light having a wavelength of 157 nm.

In the above-described embodiment, 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, a wavefront division type micro fly's eye lens (fly 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, a condensing lens is arranged on the rear side of the zoom lens 7 so that its front focal position 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 (27)

1. A spatial light modulation unit that is used together with an illumination optical system that illuminates a surface to be irradiated based on light from a light source, and that forms a desired light intensity distribution on a pupil plane of the illumination optical system,
   A first spatial light modulator that has a plurality of optical elements that are two-dimensionally arranged and individually controlled, and that emits light by applying spatial light modulation to incident light;
   A second spatial light modulator that has a plurality of optical elements that are two-dimensionally arranged and individually controlled, and that emits light by applying spatial light modulation to incident light;
   The incident light is divided into a plurality of lights, a first light of the plurality of lights is guided to the first spatial light modulator, and a second light of the plurality of lights is modulated by the second spatial light modulation. A spatial light modulation unit, comprising: a divided light guide member that leads to a vessel.
2. The first spatial light modulator and the second spatial light modulator each have a plurality of two-dimensionally arranged mirror elements and a drive unit that individually controls and drives the postures of the plurality of mirror elements. The spatial light modulation unit according to claim 1.
3. The array surface on which the plurality of mirror elements of the first spatial light modulator are arranged is substantially parallel to the array surface on which the plurality of mirror elements of the second spatial light modulator are arranged, and the first 3. The spatial light modulation according to claim 2, wherein the reflection surfaces of the plurality of mirror elements of the spatial light modulator are opposed to the reflection surfaces of the plurality of mirror elements of the second spatial light modulator. unit.
4. 4. The spatial light modulation unit according to claim 2, wherein the drive unit continuously or discretely changes the directions of the plurality of mirror elements. 5.
5. The split light guide member splits the incident light into the first light and the second light, and the first spatial light modulator passes the first light passing through the light splitter. 2. A first deflection surface that deflects toward the first and a second deflection surface that deflects the second light that has passed through the optical splitter toward the second spatial light modulator. The spatial light modulation unit according to any one of 1 to 4.
6. The spatial light modulation unit according to claim 5, wherein the light splitter includes at least one prism.
7. The spatial light modulation unit according to claim 5, wherein the light splitter includes a diffractive optical element.
8. The divided light guide member includes a first deflection surface that deflects incident light toward the first spatial light modulator, and a second deflection surface that deflects incident light toward the second spatial light modulator. The incident light is divided into the first light and the second light along a ridge line between the first deflection surface and the second deflection surface. The spatial light modulation unit according to any one of the above.
9. The spatial light modulation unit according to claim 8, wherein the divided light guide member has a form of one prism.
10. The angle formed by the first deflection surface or its extension surface and the second deflection surface or its extension surface is an acute angle, according to any one of claims 5 to 9, Spatial light modulation unit.
11. 11. The spatial light according to claim 10, wherein the first deflection surface or its extension surface and the second deflection surface or its extension surface are arranged so as to be convex with respect to incident light. Modulation unit.
12. The first deflection surface is obliquely formed at a first angle with respect to the optical axis of the illumination optical system, and the second deflection surface forms a second angle with respect to the optical axis of the illumination optical system. The spatial light modulation unit according to any one of claims 5 to 11, wherein the spatial light modulation unit is obliquely arranged so that the magnitude of the first angle and the magnitude of the second angle are equal to each other.
13. A third deflecting surface that deflects light that has passed through the first spatial light modulator toward the subsequent optical system, and a fourth deflection that deflects light that has passed through the second spatial light modulator toward the subsequent optical system. The spatial light modulation unit according to claim 1, further comprising a surface.
14. The traveling direction of the incident light incident on the divided light guide member, the traveling direction in the reference state of the emitted light emitted from the third deflection surface, and the reference of the emitted light emitted from the fourth deflection surface The spatial light modulation unit according to claim 13, wherein the traveling directions in the state are parallel to each other.
15. The traveling direction of the exit light from the third deflection surface in the reference state and the traveling direction of the exit light from the fourth deflection surface in the reference state coincide with or parallel to the optical axis of the illumination optical system. The spatial light modulation unit according to claim 14, wherein
16. 16. The optical path length from the first spatial light modulator to the third deflection surface and the optical path length from the second spatial light modulator to the fourth deflection surface are equal to each other. The spatial light modulation unit according to any one of the above.
17. The divided light guide member includes a first deflection surface that deflects incident light toward the first spatial light modulator, and a second deflection surface that deflects incident light toward the second spatial light modulator. Have
    The spatial light modulation unit according to claim 1, wherein the first deflection surface and the second deflection surface are surface reflection surfaces.
18. A third deflecting surface that deflects light that has passed through the first spatial light modulator toward the subsequent optical system, and a fourth deflection that deflects light that has passed through the second spatial light modulator toward the subsequent optical system. And further comprising a surface,
    The spatial light modulation unit according to claim 17, wherein the third deflection surface and the fourth deflection surface are surface reflection surfaces.
19. A third deflecting surface that deflects light that has passed through the first spatial light modulator toward the subsequent optical system, and a fourth deflection that deflects light that has passed through the second spatial light modulator toward the subsequent optical system. And further comprising a surface,
    18. The spatial light modulation unit according to claim 17, wherein the third deflection surface and the fourth deflection surface are inner surface reflection surfaces.
20. The spatial light modulation unit according to any one of claims 1 to 19, wherein the spatial light modulation unit can be inserted into and removed from an optical path of the illumination optical system.
21. The split light guide member splits the incident light into the plurality of lights at a light splitting surface, a first optical path from the light splitting surface to the subsequent optical system through the first spatial light modulator, The light transmitting member disposed in the second optical path from the light splitting surface through the second spatial light modulator to the subsequent optical system is a light transmitting member that maintains the polarization state of incident light. The spatial light modulation unit according to claim 1, wherein the spatial light modulation unit is a unit.
22. Arranged in at least one of the optical path between the divided light guide member and the first spatial light modulator and the optical path between the divided light guide member and the second spatial light modulator. 21. The spatial light modulation unit according to claim 1, further comprising a polarizing optical member that emits light while changing a polarization state of the light.
23. In the illumination optical system that illuminates the illuminated surface based on the light from the light source,
    The spatial light modulation unit according to any one of claims 1 to 22,
    A distribution forming optical system that forms a predetermined light intensity distribution on an illumination pupil of the illumination optical system based on the light that has passed through the first spatial light modulator and the second spatial light modulator. Characteristic illumination optical system.
24. 24. The illumination optical system according to claim 23, wherein the distribution forming optical system includes an optical integrator, and a condensing optical system disposed in an optical path between the optical integrator and the spatial light modulation unit. system.
25. The projection pupil is used in combination with a projection optical system that forms a surface optically conjugate with the irradiated surface, and the illumination pupil is at a position optically conjugate with an aperture stop of the projection optical system. The illumination optical system according to 23 or 24.
26. 26. An exposure apparatus comprising the illumination optical system according to claim 23 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate.
27. An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to claim 26;
    Developing the photosensitive substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate;
    And a processing step of processing the surface of the photosensitive substrate through the mask layer.

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