JP5326733B2 - Illumination optical system, exposure apparatus, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system capable of adjusting pupil intensity distribution at each point on a plane to be illuminated to make the distribution almost uniform. <P>SOLUTION: The illumination optical system for illuminating a plane (M; W) to be illuminated with light from a light source (1) includes an optical integrator (8), a distribution forming optical system (3, 4, 7, 8) for forming pupil intensity distribution on an illumination pupil located behind the optical integrator, and at least two light shielding members (9) arranged at a position just in front of or behind the illumination pupil and extending along a plane almost parallel to the surface of the illumination pupil so as to intersect each other. The two light shielding members are constituted so that the dimming rate, caused by the light shielding members, for the light directing toward one point on the plane to be illuminated can increase as the point moves from the center to the perimeter of the plane to be illuminated. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  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 a device such as a semiconductor element, an imaging element, a liquid crystal display element, and a thin film magnetic head in a lithography process.

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

  The light from the secondary light source is 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.

  In order to accurately transfer the fine pattern of the mask onto the wafer, for example, an annular or multipolar (bipolar, quadrupolar, etc.) pupil intensity distribution is formed to improve the depth of focus and resolution of the projection optical system. The technique to make it is proposed (refer patent document 1).

US Patent Publication No. 2006/0055834

  In order to faithfully transfer the fine pattern of the mask onto the wafer, not only the pupil intensity distribution is adjusted to the desired shape, but also the pupil intensity distribution for each point on the wafer as the final irradiated surface is almost uniform. It is necessary to adjust to. If there is a variation in the uniformity of the pupil intensity distribution at each point on the wafer, the line width of the pattern varies from position to position on the wafer, and the fine pattern of the mask has the desired line width over the entire exposure area. It cannot be faithfully transferred onto the wafer.

  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 adjusting the pupil intensity distribution at each point on the irradiated surface almost uniformly. The present invention also provides an exposure apparatus that can perform good exposure under appropriate illumination conditions using an illumination optical system that adjusts the pupil intensity distribution at each point on the irradiated surface substantially uniformly. The purpose is to provide.

  In order to solve the above-described problem, according to a first aspect of the present invention, an illumination optical system that illuminates a surface to be irradiated with light from a light source has an optical integrator, and a pupil is placed on an illumination pupil on the rear side of the optical integrator. A distribution-forming optical system that forms an intensity distribution, and at least two light-shielding members that are disposed immediately before or after the illumination pupil and extend so as to intersect each other along a plane substantially parallel to the plane of the illumination pupil The at least two light shielding members are configured such that a light reduction rate by the at least two light shielding members of light directed to one point on the irradiated surface increases from the center to the periphery of the irradiated surface. An illumination optical system is provided.

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

  In the third embodiment of the present invention, using the exposure apparatus of the second embodiment, an exposure process 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 of the present invention, at least two light-shielding members extending so as to intersect each other along a plane substantially parallel to the plane of the illumination pupil are arranged at positions immediately before or immediately after the illumination pupil behind the optical integrator. In addition, the light reduction rate of the light directed to one point on the irradiated surface by the light blocking member increases from the center to the periphery of the irradiated surface. Accordingly, the pupil intensity distribution for each point on the illuminated surface is independently adjusted by the dimming action of the light shielding member having a required dimming rate characteristic that changes according to the incident position of light on the illuminated surface. Thus, it is possible to adjust the pupil intensity distribution for each point to distributions having substantially the same properties.

  As a result, in the illumination optical system of the present invention, for example, a correction filter that uniformly adjusts the pupil intensity distribution at each point on the irradiated surface and a light shielding member that independently adjusts the pupil intensity distribution for each point. Due to the cooperative action, the pupil intensity distribution at each point on the irradiated surface can be adjusted substantially uniformly. Thus, the exposure apparatus of the present invention can perform good exposure under appropriate illumination conditions using the illumination optical system that adjusts the pupil intensity distribution at each point on the irradiated surface almost uniformly. And by extension, a good device can be manufactured.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows the quadrupole secondary light source formed in an illumination pupil. It is a figure which shows the rectangular-shaped static exposure area | region formed on a wafer. It is a figure explaining the property of the quadrupole pupil intensity distribution which the light which injects into the center point P1 in a still exposure area | region forms. It is a figure explaining the property of the quadrupole pupil intensity distribution which the light which injects into the peripheral points P2 and P3 in a still exposure area | region forms. (A) is a light intensity distribution along the Z direction of the pupil intensity distribution with respect to the center point P1, and (b) is a diagram schematically showing the light intensity distribution along the Z direction of the pupil intensity distribution with respect to the peripheral points P2 and P3. It is. It is a 1st figure explaining the effect | action of a single fin member. It is a 2nd figure explaining the effect | action of a single fin member. It is a figure which shows the light attenuation rate characteristic of a single fin member. It is a figure which shows typically a mode that the pupil intensity distribution regarding the center point P1 is adjusted with a single fin member. It is a figure which shows typically a mode that the pupil intensity distribution regarding the peripheral points P2, P3 is adjusted with a single fin member. It is a 1st figure explaining the problem which generate | occur | produces when using the fin member extended substantially parallel to a X direction. It is a 2nd figure explaining the problem which generate | occur | produces when using the fin member extended substantially parallel to a X direction. It is a figure which shows the positional relationship of a quadrupole secondary light source formed in an illumination pupil, and a pair of light shielding member which comprises the light-shielding part concerning this embodiment. FIG. 13 is a diagram for explaining that the inconvenience shown in FIG. 12 is avoided by using a pair of light shielding members according to the present embodiment. FIG. 14 is a diagram illustrating that the inconvenience shown in FIG. 13 is avoided by using a pair of light shielding members according to the present embodiment. It is a figure explaining the influence of the parallax in this embodiment. It is a figure explaining the influence of the parallax in the comparative example of this embodiment. It is a figure which shows the structure of the light-shielding part concerning the 1st modification of this embodiment. It is a figure which shows the structure of the light-shielding part concerning the 2nd modification of this embodiment. It is a figure which shows the structure of the light-shielding part concerning the 3rd modification of this embodiment. It is a figure which shows the structure of the light-shielding part concerning the 4th modification of this embodiment. It is a figure which shows the structure of an example of a correction filter. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

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

  Referring to FIG. 1, in the exposure apparatus of the present embodiment, exposure light (illumination light) is supplied from a light source 1. As the light source 1, for example, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. The light beam emitted from the light source 1 is converted into a light beam having a required cross-sectional shape by the shaping optical system 2 and then enters the afocal lens 4 via the diffractive optical element 3 for annular illumination, for example.

  The afocal lens 4 is set so that the front focal position thereof and the position of the diffractive optical element 3 substantially coincide with each other, and the rear focal position thereof substantially coincides with the position of the predetermined surface 5 indicated by a broken line in the drawing. System (non-focal optical system). The diffractive optical element 3 is formed by forming a step having a pitch of about the wavelength of exposure light (illumination light) on the substrate, and has a function of diffracting an incident beam to a desired angle. Specifically, the diffractive optical element 3 for annular illumination has a function of forming an annular light intensity distribution in the far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. Have

  Therefore, the substantially parallel light beam incident on the diffractive optical element 3 is emitted from the afocal lens 4 with a ring-shaped angular distribution after forming a ring-shaped light intensity distribution on the pupil plane of the afocal lens 4. In the optical path between the front lens group 4a and the rear lens group 4b of the afocal lens 4, a correction filter 6 is disposed at or near the pupil position. The correction filter 6 has a shape of a plane parallel plate, and a dense pattern of light-shielding dots made of chromium, chromium oxide or the like is formed on the optical surface thereof. That is, the correction filter 6 has a transmittance distribution with different transmittances depending on the incident position of light. The specific operation of the correction filter 6 will be described later.

  The light passing through the afocal lens 4 passes through a zoom lens 7 for varying a σ value (σ value = mask-side numerical aperture of the illumination optical system / mask-side numerical aperture of the projection optical system), and is a micro fly as an optical integrator. The light enters the eye lens (or fly eye lens) 8. The micro fly's eye lens 8 is, for example, an optical element composed of a large number of micro lenses having positive refracting power arranged vertically and horizontally and densely, and by performing etching treatment on a parallel plane plate, a micro lens group is formed. It is configured.

  Each micro lens constituting the micro fly's eye lens is smaller than each lens element constituting the fly eye lens. Further, unlike a fly-eye lens composed of lens elements isolated from each other, a micro fly-eye lens is formed integrally with a large number of micro lenses (micro refractive surfaces) without being isolated from each other. However, the micro fly's eye lens is the same wavefront division type optical integrator as the fly eye lens in that lens elements having positive refractive power are arranged vertically and horizontally. As the micro fly's eye lens 8, for example, a cylindrical micro fly's eye lens can be used. The configuration and action of the cylindrical micro fly's eye lens are disclosed in, for example, US Pat. No. 6,913,373.

  The position of the predetermined surface 5 is disposed at or near the front focal position of the zoom lens 7, and the incident surface of the micro fly's eye lens 8 is disposed at or near the rear focal position of the zoom lens 7. In other words, the zoom lens 7 arranges the predetermined surface 5 and the incident surface of the micro fly's eye lens 8 substantially in a Fourier transform relationship, and consequently the pupil surface of the afocal lens 4 and the incident surface of the micro fly's eye lens 8. Are arranged almost conjugate optically.

  Accordingly, on the incident surface of the micro fly's eye lens 8, for example, a ring-shaped illumination field centered on the optical axis AX is formed in the same manner as the pupil surface of the afocal lens 4. The overall shape of the annular illumination field changes in a similar manner depending on the focal length of the zoom lens 7. The incident surface (that is, the unit wavefront dividing surface) of each microlens in the micro fly's eye lens 8 is a rectangular shape having a long side along the Z direction and a short side along the X direction, for example. It has a rectangular shape similar to the shape of the illumination area to be formed above (and thus the shape of the exposure area to be formed on the wafer W).

  The light beam incident on the micro fly's eye lens 8 is two-dimensionally divided, and an illumination field formed on the incident surface of the micro fly's eye lens 8 at the rear focal plane or a position in the vicinity thereof (and hence the position of the illumination pupil). A secondary light source having substantially the same light intensity distribution as the light source, that is, a secondary light source (pupil intensity distribution) composed of a ring-shaped substantial surface light source centered on the optical axis AX. A light shielding portion 9 is disposed on the rear focal plane of the micro fly's eye lens 8 or in the vicinity thereof. The configuration and operation of the light shielding unit 9 will be described later.

  An illumination aperture stop (not shown) having a ring-shaped opening (light transmitting part) corresponding to a ring-shaped secondary light source on the rear focal plane of the micro fly's eye lens 8 or in the vicinity thereof if necessary. ) Is arranged. The illumination aperture stop is configured to be detachable with respect to the illumination optical path, and is configured to be switchable with a plurality of aperture stops having apertures having different sizes and shapes. As an aperture stop switching method, for example, a well-known turret method or slide method can be used. The illumination aperture stop is disposed at a position 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 that has passed through the micro fly's eye lens 8 and the light shielding unit 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 microlens of the micro fly's eye lens 8 is formed on the mask blind 11 as an illumination field stop. The light that has passed through the rectangular opening (light transmission portion) of the mask blind 11 passes through the imaging optical system 12 including the front lens group 12a and the rear lens group 12b, and the mask M on which a predetermined pattern is formed. Are illuminated in a superimposed manner. That is, the imaging optical system 12 forms an image of the rectangular opening of the mask blind 11 on the mask M.

  A pattern to be transferred is formed on the mask M held on the mask stage MS, and a rectangular shape having a long side along the Y direction and a short side along the X direction in the entire pattern region ( The pattern area of the slit shape is illuminated. The light transmitted through the pattern area of the mask M forms an image of the mask pattern on the wafer (photosensitive substrate) W held on the wafer stage WS via the projection optical system PL. That is, a rectangular stationary image having a long side along the Y direction and a short side along the X direction on the wafer W so as to optically correspond to the rectangular illumination area on the mask M. A pattern image is formed in the exposure area (effective exposure area).

  Thus, according to the so-called step-and-scan method, the mask stage MS and the wafer stage WS along the X direction (scanning direction) in the plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, As a result, by moving (scanning) the mask M and the wafer W synchronously, the wafer W has a width equal to the dimension in the Y direction of the static exposure region and corresponds to the scanning amount (movement amount) of the wafer W. A mask pattern is scanned and exposed to a shot area (exposure area) having a length.

  In the present embodiment, as described above, the secondary light source formed by the micro fly's eye lens 8 is used as a light source, and the mask M arranged on the irradiated surface of the illumination optical system (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 pupil intensity 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 micro fly's eye lens 8 is relatively large, the overall light intensity distribution formed on the incident surface of the micro fly's eye lens 8 and the overall light intensity distribution of the entire secondary light source (pupil intensity distribution). ) And a high correlation. For this reason, the light intensity distribution on the incident surface of the micro fly's eye lens 8 and the surface optically conjugate with the incident surface can also be referred to as a pupil intensity distribution. In the configuration of FIG. 1, the diffractive optical element 3, the afocal lens 4, the zoom lens 7, and the micro fly's eye lens 8 are distribution forming optics that form a pupil intensity distribution in the illumination pupil behind the micro fly's eye lens 8. The system is configured.

  In place of the diffractive optical element 3 for annular illumination, a plurality of diffractive optical elements (not shown) for multipole illumination (two-pole illumination, four-pole illumination, octupole illumination, etc.) are set in the illumination optical path. Polar lighting can be performed. A diffractive optical element for multipole illumination forms a light intensity distribution of multiple poles (bipolar, quadrupole, octupole, etc.) in the far field when a parallel light beam having a rectangular cross section is incident. It has the function to do. Accordingly, the light beam that has passed through the diffractive optical element for multipole illumination is incident on the incident surface of the micro fly's eye lens 8 from, for example, an illumination field having a plurality of predetermined shapes (arc shape, circular shape, etc.) centered on the optical axis AX. To form a multipolar illuminator. As a result, the same multipolar secondary light source as the illumination field formed on the incident surface is also formed on or near the rear focal plane of the micro fly's eye lens 8.

  Moreover, instead of the diffractive optical element 3 for annular illumination, a normal circular illumination can be performed by setting a diffractive optical element (not shown) for circular illumination in the illumination optical path. The diffractive optical element for circular illumination has a function of forming a circular light intensity distribution in the far field when a parallel light beam having a rectangular cross section is incident. Therefore, the light beam that has passed through the diffractive optical element for circular illumination forms, for example, a circular illumination field around the optical axis AX on the incident surface of the micro fly's eye lens 8. As a result, a secondary light source having the same circular shape as the illumination field formed on the incident surface is also formed on or near the rear focal plane of the micro fly's eye lens 8. Also, instead of the diffractive optical element 3 for annular illumination, various forms of modified illumination can be performed by setting a diffractive optical element (not shown) having appropriate characteristics in the illumination optical path. As a switching method of the diffractive optical element 3, for example, a known turret method or slide method can be used.

  In the following description, in order to facilitate understanding of the operational effects of the present embodiment, a quadrupole pupil as shown in FIG. It is assumed that an intensity distribution (secondary light source) 20 is formed. In order to facilitate understanding of the principle of the present invention, a single fin member (light shielding member having a plate-like shape) 90 extending substantially parallel to the X direction is used instead of the light shielding portion 9 according to the present embodiment. It is assumed that the quadrupole pupil intensity distribution 20 is arranged immediately after the formation surface. Further, in the following description, the term “illumination pupil” simply refers to the illumination pupil in the rear focal plane of the micro fly's eye lens 8 or in the vicinity thereof.

  Referring to FIG. 2, a quadrupole pupil intensity distribution 20 formed on the illumination pupil has a pair of arc-shaped substantial surface light sources (hereinafter simply referred to as “a” and “a”) spaced apart in the X direction across the optical axis AX. 20a, 20b) and a pair of arcuate substantial surface light sources 20c, 20d spaced apart in the Z direction across the optical axis AX. The X direction in the illumination pupil is the short side direction of the rectangular microlens of the micro fly's eye lens 8 and corresponds to the scanning direction of the wafer W. The Z direction in the illumination pupil is the long side direction of the rectangular microlens of the micro fly's eye lens 8 and corresponds to the scanning orthogonal direction (Y direction on the wafer W) perpendicular to the scanning direction of the wafer W. ing.

  On the wafer W, as shown in FIG. 3, a rectangular still exposure region ER having a long side along the Y direction and a short side along the X direction is formed. Correspondingly, a rectangular illumination area (not shown) is formed on the mask M. Here, the quadrupole pupil intensity distribution formed on the illumination pupil by light incident on one point in the still exposure region ER has substantially the same shape without depending on the position of the incident point. However, the light intensity of each surface light source constituting the quadrupole pupil intensity distribution tends to differ depending on the position of the incident point.

  Specifically, as shown in FIG. 4, in the case of a quadrupole pupil intensity distribution 21 formed by light incident on the central point P1 in the still exposure region ER, the surface light source 21c and the surface light source 21c spaced apart in the Z direction and The light intensity of 21d tends to be higher than the light intensity of the surface light sources 21a and 21b spaced apart in the X direction. On the other hand, as shown in FIG. 5, in the case of a quadrupole pupil intensity distribution 22 formed by light incident on peripheral points P2 and P3 spaced from the central point P1 in the still exposure region ER in the Y direction, The light intensities of the surface light sources 22c and 22d spaced in the Z direction tend to be smaller than the light intensities of the surface light sources 22a and 22b spaced in the X direction.

  In general, regardless of the outer shape of the pupil intensity distribution formed on the illumination pupil, the pupil intensity distribution related to the center point P1 in the still exposure region ER on the wafer W (the pupil formed on the illumination pupil by the light incident on the center point P1). As shown in FIG. 6A, the light intensity distribution along the Z direction of the intensity distribution has a concave curve distribution that is the smallest at the center and increases toward the periphery. On the other hand, the light intensity distribution along the Z direction of the pupil intensity distribution related to the peripheral points P2 and P3 in the static exposure region ER on the wafer W is the largest at the center and toward the periphery as shown in FIG. It has a decreasing convex curve distribution.

  The light intensity distribution along the Z direction of the pupil intensity distribution does not depend much on the position of the incident point along the X direction (scanning direction) in the still exposure region ER, but the Y direction in the still exposure region ER. There is a tendency to change depending on the position of the incident point along the (scanning orthogonal direction). As described above, when the pupil intensity distribution (pupil intensity distribution formed on the illumination pupil by the light incident on each point) on each point in the still exposure region ER on the wafer W is not substantially uniform, for each position on the wafer W. Further, the line width of the pattern varies, and the fine pattern of the mask M cannot be faithfully transferred onto the wafer W with a desired line width over the entire exposure region.

  In the present embodiment, as described above, the correction filter 6 having a transmittance distribution with different transmittance according to the incident position of light is disposed at or near the pupil position of the afocal lens 4. The pupil position of the afocal lens 4 is optically conjugate with the incident surface of the micro fly's eye lens 8 by the rear lens group 4b and the zoom lens 7. Therefore, the light intensity distribution formed on the incident surface of the micro fly's eye lens 8 is adjusted (corrected) by the action of the correction filter 6, and as a result, formed on the rear focal plane of the micro fly's eye lens 8 or the illumination pupil in the vicinity thereof. The pupil intensity distribution to be adjusted is also adjusted.

  However, the correction filter 6 uniformly adjusts the pupil intensity distribution for each point in the still exposure region ER on the wafer W without depending on the position of each point. As a result, by the action of the correction filter 6, for example, adjustment is made so that the quadrupole pupil intensity distribution 21 with respect to the center point P <b> 1 becomes substantially uniform, and thus the light intensities of the surface light sources 21 a to 21 d become substantially equal to each other. In this case, however, the difference in light intensity between the surface light sources 22a and 22b and the surface light sources 22c and 22d in the quadrupole pupil intensity distribution 22 with respect to the peripheral points P2 and P3 becomes larger.

  That is, in order to adjust the pupil intensity distribution relating to each point in the static exposure region ER on the wafer W almost uniformly by the action of the correction filter 6, the pupil intensity relating to each point may be adjusted by means other than the correction filter 6. It is necessary to adjust the distribution to distributions having the same properties. Specifically, for example, in the pupil intensity distribution 21 related to the center point P1 and the pupil intensity distribution 22 related to the peripheral points P2 and P3, the magnitude relationship between the light intensities of the surface light sources 21a and 21b and the surface light sources 21c and 21d and the surface light sources 22a and 22a. It is necessary to match the magnitude relationship of the light intensity between 22b and the surface light sources 22c and 22d at substantially the same ratio.

  In the present embodiment, in order to make the properties of the pupil intensity distribution related to the center point P1 and the properties of the pupil intensity distribution related to the peripheral points P2 and P3 substantially coincide, the surface light sources 22a and 22b in the pupil intensity distribution 22 related to the peripheral points P2 and P3. The light shielding part 9 is provided as an adjusting means for adjusting the light intensity of the light source 22c and 22d to be smaller than the light intensity of the surface light sources 22c and 22d. However, as described above, in order to facilitate understanding of the principle of the present invention, a configuration including a single fin member 90 having a dimming action according to the same principle as the light shielding unit 9 according to the present embodiment is considered. To do. 7 and 8 are diagrams for explaining the operation of the single fin member 90. FIG. FIG. 9 is a diagram illustrating the light attenuation rate characteristic of the single fin member 90.

  As shown in FIG. 2, the plate-shaped fin member 90 is positioned substantially parallel to the X direction so as to correspond to a pair of surface light sources 20a and 20b spaced in the X direction across the optical axis AX. Has been. Specifically, the fin member 90 has, for example, a shape of a parallel plane plate having a rectangular outer shape, and its thickness direction (Z direction) is substantially parallel to the plane of the illumination pupil (XZ plane), and They are arranged such that the width direction (Y direction) is substantially parallel to the direction of the optical axis AX. That is, the thickness direction of the fin member 90 substantially coincides with the long side direction of the rectangular unit wavefront dividing surface of the micro fly's eye lens 8.

  Therefore, in the quadrupole pupil intensity distribution 20, light from the surface light sources 20 a and 20 b is affected by the fin member 90, but light from the surface light sources 20 c and 20 d is not affected by the fin member 90. In this case, as shown in FIG. 7, the light reaching the center point P 1 in the static exposure region ER on the wafer W, that is, the light reaching the center point P 1 ′ of the opening of the mask blind 11 is illuminated by the illumination pupil of the fin member 90. Since the incident angle is 0 with respect to the XZ plane on the side end face, the amount of light blocked by the fin member 90 is small. In other words, the attenuation rate of the light from the surface light sources 21a and 21b of the pupil intensity distribution 21 with respect to the center point P1 by the fin member 90 becomes a value close to 0%.

  On the other hand, as shown in FIG. 8, the light reaching the peripheral points P2 and P3 in the static exposure region ER on the wafer W, that is, the light reaching the peripheral points P2 ′ and P3 ′ of the opening of the mask blind 11 is Since the light is incident at an incident angle ± θ on the XZ plane on the end face on the illumination pupil side of 90, the amount of light blocked by the fin member 90 is relatively large. In other words, the light attenuation rate by the fin member 90 of the light from the surface light sources 22a and 22b of the pupil intensity distribution 22 regarding the peripheral points P2 and P3 is a relatively large value according to the magnitude of the absolute value of the incident angle ± θ. become.

  In this way, the light attenuation rate by the fin member 90 of light directed to one point on the stationary exposure region ER that is the irradiated surface is as shown in FIG. 9 with respect to the XZ plane on the end face of the fin member 90 on the illumination pupil side. It is configured to increase in accordance with the magnitude of the absolute value of the incident angle, that is, to increase from the center to the periphery of the static exposure region ER. More specifically, the fin member 90 extends along the long side direction (Z direction: Y direction on the static exposure region ER) of the rectangular unit wavefront dividing surface of the micro fly's eye lens 8 in the static exposure region ER. The dimming rate increases from the center to the periphery.

  7 and 8, reference numeral B1 indicates the outermost point (see FIG. 2) along the X direction of the surface light source 20a (21a, 22a), and reference numeral B2 indicates the surface light source 20b (21b, 21b, 21a, 22a). 22b) shows the outermost point along the X direction (see FIG. 2). Further, in order to facilitate understanding of the explanation related to FIGS. 7 and 8, the point of the outermost edge along the Z direction of the surface light source 20c (21c, 22c) is indicated by reference numeral B3, and the surface light source 20d (21d, 21d, The point of the outermost edge along the Z direction of 22d) is indicated by reference numeral B4. However, as described above, the light from the surface light source 20c (21c, 22c) and the surface light source 20d (21d, 22d) does not receive the dimming action of the fin member 90.

  Thus, in the pupil intensity distribution 21 related to the center point P1, the light from the surface light sources 21a and 21b receives the dimming action of the fin member 90, but the light intensity hardly changes. Since the light from the surface light sources 21c and 21d does not receive the dimming action of the fin member 90, the light intensity does not change. As a result, as shown in FIG. 10, the pupil intensity distribution 21 related to the center point P1 is slightly adjusted to a pupil intensity distribution 21 ′ having substantially the same properties as the original distribution 21 even when the fin member 90 is dimmed. It is only done. That is, also in the pupil intensity distribution 21 ′ adjusted by the fin member 90, the light intensity of the surface light sources 21c and 21d spaced in the Z direction is higher than that of the surface light sources 21a ′ and 21b ′ spaced in the X direction. Properties greater than light intensity are maintained.

  On the other hand, in the pupil intensity distribution 22 relating to the peripheral points P2 and P3, the light from the surface light sources 22a and 22b is subjected to the dimming action of the fin member 90, and the light intensity is reduced. Since the light from the surface light sources 22c and 22d does not receive the dimming action of the fin member 90, the light intensity does not change. As a result, the pupil intensity distribution 22 relating to the peripheral points P2 and P3 is adjusted to a pupil intensity distribution 22 'having a property different from that of the original distribution 22 by the dimming action of the fin member 90, as shown in FIG. That is, in the pupil intensity distribution 22 ′ adjusted by the fin member 90, the light intensity of the surface light sources 22c and 22d spaced in the Z direction is light of the surface light sources 22a ′ and 22b ′ spaced in the X direction. It changes to a property larger than strength.

  Thus, due to the dimming action of the fin member 90, the pupil intensity distribution 22 relating to the peripheral points P2 and P3 is adjusted to a distribution 22 'having substantially the same properties as the pupil intensity distribution 21' relating to the center point P1. Similarly, the pupil intensity distribution for each point arranged along the Y direction between the center point P1 and the peripheral points P2 and P3, and hence the pupil intensity distribution for each point in the still exposure region ER on the wafer W is also the center. The distribution is adjusted to a distribution having substantially the same property as the pupil intensity distribution 21 ′ relating to the point P1. In other words, the pupil intensity distribution for each point in the still exposure region ER on the wafer W is adjusted to a distribution having substantially the same property by the dimming action of the fin member 90. In other words, the fin member 90 has a required dimming rate characteristic necessary for adjusting the pupil intensity distribution regarding each point to a distribution having substantially the same property.

  As described above, in the configuration of the illumination optical system (2 to 12) shown in FIG. 1, when the single fin member 90 extending substantially parallel to the X direction is disposed immediately after the pupil intensity distribution forming surface (that is, the illumination pupil). Fin having a required light attenuation rate characteristic that changes in accordance with the incident position of light on the static exposure region ER on the wafer W and independently adjusting the pupil intensity distribution for each point in the static exposure region ER By the cooperative action of the member 90 and the correction filter 6 that uniformly adjusts the pupil intensity distribution for each point in the still exposure region ER, the pupil intensity distribution for each point can be adjusted substantially uniformly.

  However, when the fin member 90 extending substantially parallel to the short side direction of the rectangular unit wavefront dividing surface 8a of the micro fly's eye lens 8 as shown in FIG. there is a possibility. In FIG. 12, only a part of the unit wavefront dividing surface 8a of the micro fly's eye lens 8 is shown, and the small light source 23 (schematically shaped oval shape with hatching) corresponding to all the unit wavefront dividing surfaces 8a illustrated. Is shown). 12, the single fin member 90 is slightly tilted with respect to the X direction (in FIG. 12, the tilt angle is exaggerated for easy understanding of the explanation. In the case of being arranged at a certain angle), as shown in the right side of FIG. 12, a single unit is used for the light from the small light source 23 formed corresponding to the black unit wavefront dividing plane 8a. The fin member 90 exhibits a dimming effect. In other words, among a series of unit wavefront dividing surfaces 8a opposed to a single fin member 90 indicated by a broken line in the drawing on the right side of FIG. 12, a relatively large number of unit wavefront dividing surfaces 8a that do not receive a dimming action are single. The fin member 90 continuously exists along the longitudinal direction.

  As a result, as shown in FIG. 13, in the quadrupole pupil intensity distribution 24 related to a certain point in the static exposure region ER on the wafer W, a pair of surface light sources spaced apart in the X direction across the optical axis AX. Of the 24 a and 24 b, for example, one surface light source 24 b may not be able to receive the desired dimming action of the fin member 90. In FIG. 13, the dimming effect on the surface light sources 24a and 24b of the three fin members 90 extending substantially parallel to the X direction is schematically represented by line segments extending in the X direction. In FIG. 13, all the three fin members 90 exhibit the desired dimming effect on the surface light source 24a, and the fin members 90 at both ends exhibit the desired dimming effect on the surface light source 24b. Illustrates the state in which the fin member 90 at the center hardly exhibits a dimming action. In this case, the surface light source 24b cannot be adjusted to a desired light intensity, and as a result, the light intensity balance is lost between the surface light sources 24a and 24b spaced in the X direction across the optical axis AX. .

  2, in addition to the single fin member 90, one or a plurality of fin members (for example, fin members having the same configuration as the single fin member 90) that extend substantially parallel to the X direction are arranged. However, like the single fin member 90, the plurality of fin members parallel to each other have a light attenuation rate characteristic that increases the light attenuation rate from the center to the periphery of the static exposure region ER. Further, in FIG. 2, the single fin member 90 is rotated by an appropriate angle (for example, an arbitrary angle of 45 degrees or less) around the optical axis AX so that the single fin member 90 extends in a direction intersecting the X direction. However, the single fin member 90 inclined with respect to the X direction is dimmed from the center of the static exposure region ER to the periphery in the same manner as the single fin member 90 extending substantially parallel to the X direction. It has a light attenuation rate characteristic that increases the rate. In other words, from the center of the static exposure region ER by appropriately setting the number and orientation of fin members arranged along a plane substantially parallel to the plane of the illumination pupil (XZ plane) at a position immediately after the illumination pupil. It is possible to secure a desired dimming rate characteristic such that the dimming rate increases toward the periphery, and by extension, the pupil intensity distribution for each point in the still exposure region ER can be independently adjusted as desired.

  Therefore, in the present embodiment, as shown in FIG. 14, a pair of light shielding members 9 a and 9 b arranged at positions immediately after the illumination pupil and extending so as to intersect each other along a plane substantially parallel to the plane of the illumination pupil. The light shielding part 9 is provided. Hereinafter, in order to simplify the description, the pair of light shielding members 9a and 9b have the same configuration (for example, the same form of plates extending along a plane perpendicular to the paper surface of FIG. 14), and in the X direction. It is assumed that they are inclined by the same angle. That is, the pair of light shielding members 9a and 9b is inclined with respect to the X direction by a required angle appropriately selected in an angular range overlapping with the pair of surface light sources 20a and 20b spaced apart in the X direction with the optical axis AX interposed therebetween. Thus, it shall be symmetrically arrange | positioned regarding the axis line which passes along the optical axis AX and extends to a X direction.

  In this case, as shown in the upper diagram of FIG. 15, one light shielding member 9a is inclined relatively greatly with respect to the X direction (in FIG. 15, the inclination angle is larger than the angle shown in FIG. 14 for easy understanding of the explanation). 15 corresponds to the black unit wavefront dividing planes 8a that are scattered substantially continuously along the longitudinal direction of the light shielding member 9a as shown in the lower drawing of FIG. Thus, the light reducing effect is exerted on the light from the small light source 23 formed. Similarly, the other light-shielding member 9b is also arranged with a relatively large inclination with respect to the X direction. Therefore, as shown in the lower diagram of FIG. 15, the dots are substantially continuous along the longitudinal direction of the light-shielding member 9b. A dimming action is exerted on the light from the small light source 23 formed corresponding to the existing black unit wavefront dividing surface 8a. In other words, in the series of unit wavefront dividing surfaces 8a facing the pair of light shielding members 9a and 9b indicated by broken lines in the lower diagram of FIG. Inconveniences, such as those that may occur when using fin members that extend substantially parallel to the X direction, are avoided.

  Therefore, in the present embodiment, unlike the case where one or a plurality of fin members 90 extending substantially parallel to the X direction are used, as shown in FIG. In the polar pupil intensity distribution 24, the pair of light shielding members 9a and 9b exerts a required dimming action on the pair of surface light sources 24a and 24b spaced apart in the X direction across the optical axis AX. The lack of light intensity balance between the surface light sources 24a and 24b is avoided. In FIG. 16, the dimming effect on the surface light sources 24a and 24b of the pair of light shielding members 9a and 9b arranged to be inclined with respect to the X direction is schematically represented by line segments inclined with respect to the X direction. .

  In the present embodiment, the pair of light shielding members 9a and 9b constituting the light shielding unit 9 is disposed at a position immediately after the illumination pupil, which is a surface on which the pupil intensity distribution is formed, and has a predetermined dimension in the optical axis AX direction. It has a plate shape. Therefore, as shown in FIG. 17, due to the effect of so-called parallax, the position of the dimming action on the pupil intensity distribution of the pair of light shielding members 9 a and 9 b becomes the position of the point of interest in the still exposure region ER on the wafer W. Accordingly, the position shifts in the Z direction. It can be easily estimated from FIGS. 7 and 8 regarding the single fin member 90 that the position of the dimming effect on the pupil intensity distribution of the pair of light shielding members 9a and 9b is shifted due to the influence of parallax.

  In FIG. 17, the position of the light-reducing effect on the pupil intensity distribution of the pair of light shielding members 9a and 9b is schematically represented by line segments 9aa and 9ba inclined with respect to the X direction, respectively. Specifically, as shown in the center diagram of FIG. 17, a pair of light shielding members 9a for the quadrupole pupil intensity distribution 25 (25a to 25d) formed by the light incident on the center point P1 in the still exposure region ER. , 9b are hardly affected by the parallax. Therefore, the surface light sources 25a and 25b spaced apart in the X direction are subjected to a required dimming action by the pair of light shielding members 9a and 9b.

  On the other hand, as shown in the left and right diagrams of FIG. 17, a quadrupole pupil formed by light incident on a peripheral point P2 or P3 spaced from the center point P1 in the still exposure region ER in the Y direction. The dimming positions 9aa and 9ba of the pair of light shielding members 9a and 9b with respect to the intensity distribution 26 (26a to 26d) or the pupil intensity distribution 27 (27a to 27d) are displaced in the Z direction due to the influence of parallax. That is, as shown in the diagram on the left side of FIG. 17, out of the surface light sources 26a and 26b spaced apart in the X direction, the surface light source 26a is subjected to the light reducing action by the light shielding member 9b, but the light reducing action by the light shielding member 9a. There is a possibility of not receiving. On the contrary, the surface light source 26b is subjected to the dimming action by the light shielding member 9a, but may not be dimmed by the light shielding member 9b.

  Further, as shown in the right side of FIG. 17, of the surface light sources 27a and 27b spaced in the X direction, the surface light source 27a is subjected to the light reducing action by the light shielding member 9a, but the light reducing action by the light shielding member 9b. There is a possibility of not receiving. On the contrary, the surface light source 27b is subjected to the dimming action by the light shielding member 9b, but may not be dimmed by the light shielding member 9a. However, in the present embodiment, as is apparent with reference to FIG. 17, the pair of light shielding members 9a and 9b are arranged so as to intersect with each other, and therefore enter an arbitrary point in the still exposure region ER. In the quadrupole pupil intensity distribution formed by light, the dimming effect on a pair of surface light sources spaced in the X direction is the same even when affected by parallax, and thus a pair of surfaces spaced in the X direction. There is no lack of balance of light intensity among the light sources.

  Incidentally, in the comparative example using only one light shielding member 9a, as shown in FIG. 18, the dimming effect on a pair of surface light sources spaced in the X direction may be completely different due to the influence of parallax. There is. That is, as shown in the center diagram of FIG. 18, the surface light sources 25a and 25b are subjected to the required dimming action by the light shielding member 9a with almost no influence of the parallax. However, as shown on the left side of FIG. 18, the surface light source 26b is subjected to the dimming action by the light shielding member 9a, but the surface light source 26a may not be dimmed by the light shielding member 9a. Further, as shown in the right side of FIG. 18, the surface light source 27a is subjected to the dimming action by the light shielding member 9a, but the surface light source 27b may not be dimmed by the light shielding member 9a. Thus, the possibility of lacking the balance of light intensity between a pair of surface light sources facing each other due to the influence of parallax is in addition to one light shielding member 9a, one or more light shielding members extending substantially parallel to the light shielding member 9a. The same applies even if a fin member (for example, a fin member having the same configuration as the light shielding member 9a) is disposed.

  As described above, in the illumination optical system (2 to 12) of the present embodiment, a pair of light shields arranged at positions immediately after the illumination pupil and extending so as to intersect each other along a plane substantially parallel to the plane of the illumination pupil. A light-shielding portion 9 composed of members 9a and 9b is provided. As a result, inconveniences that may occur when using a single fin member 90 that extends substantially parallel to the X direction or one or more fin members that are tilted in substantially the same direction with respect to the X direction. While avoiding, it has a required dimming rate characteristic that changes in accordance with the incident position of light on the static exposure region ER on the wafer W, and independently distributes the pupil intensity distribution for each point in the static exposure region ER. By cooperating with the pair of light shielding members 9a and 9b to be adjusted and the correction filter 6 for uniformly adjusting the pupil intensity distribution for each point in the still exposure region ER, the pupil intensity distribution for each point is adjusted substantially uniformly. can do.

  Therefore, the exposure apparatus (1 to WS) of the present embodiment uses the illumination optical system (2 to 12) that adjusts the pupil intensity distribution at each point in the static exposure region ER on the wafer W almost uniformly. Therefore, it is possible to perform good exposure under appropriate illumination conditions according to the fine pattern of the mask M. As a result, the fine pattern of the mask M is faithfully applied on the wafer W with a desired line width over the entire exposure region. Can be transferred to.

  In the present embodiment, it is conceivable that the light amount distribution on the wafer (irradiated surface) W is affected by, for example, the dimming action (adjusting action) of the light shielding unit 9. In this case, the illuminance distribution in the still exposure region ER or the shape of the still exposure region (illumination region) ER can be changed as necessary by the action of the light quantity distribution adjusting unit having a known configuration. Specifically, as the light amount distribution adjusting unit for changing the illuminance distribution, configurations described in Japanese Patent Application Laid-Open Nos. 2001-313250 and 2002-1000056 (and US Pat. Nos. 6,771,350 and 6927836 corresponding thereto). And techniques can be used. Further, as the light amount distribution adjusting unit for changing the shape of the illumination area, the configuration and method described in the pamphlet of International Patent Publication No. WO2005 / 048326 (and the corresponding US Patent Publication No. 2007/0014112) are used. Can do.

  In the above-described embodiment, the pair of light shielding members 9a and 9b in which the members actually intersect each other at or near the position of the optical axis AX is used. However, the present invention is not limited to this. For example, as shown in FIG. 19, a pair of light shielding members 9c and 9d disposed to face the surface light source 20a and a pair of light shielding members disposed to face the surface light source 20b. Obviously, the use of the members 9e and 9f provides the same effects as those of the above-described embodiment. Here, the light shielding members 9c and 9f correspond to a part of the light shielding member 9a, and the light shielding members 9d and 9e correspond to a part of the light shielding member 9b. It is clear that the same effects as those of the above-described embodiment can be obtained even if the inclination angles of the light shielding members 9c to 9f with respect to the X direction are appropriately changed.

  That is, the light-shielding portion according to the present invention has at least two light-shielding members extending so as to intersect each other along a plane substantially parallel to the surface of the illumination pupil, and the light-shielding portion for light directed to one point on the irradiated surface. It is important that the dimming rate due to is increased from the center to the periphery of the irradiated surface. Here, for example, two light-shielding members (a pair of light-shielding members 9c and 9d in FIG. 19 or a pair of light-shielding members 9e and 9f) arranged substantially symmetrically with respect to a predetermined axis passing through the optical axis actually intersect each other. It is not necessary that the extension lines in the longitudinal direction intersect with each other. As described above, various configurations are possible for the configuration of the light shielding unit 9.

  As an example, as shown in FIG. 20, a light-shielding portion 9 having a mesh shape along a plane substantially parallel to the plane of the illumination pupil can be used. The light shielding unit 9 is arranged so as to act on the light from the surface light source 20a and has a mesh shape, and is arranged so as to act on the light from the surface light source 20b. A second light shielding member group 9h having a shape. The first light shielding member group 9g and the second light shielding member group 9h are configured substantially symmetrically with respect to, for example, an axis extending through the optical axis AX in the Z direction and an axis extending through the optical axis AX in the X direction.

  In this case, the light shielding member 9j as a unit member constituting the mesh-shaped first light shielding member group 9g and the second light shielding member group 9h can be considered as a member corresponding to one side of one rectangular mesh, It can also be considered as a member extending in a straight line connecting each side of a plurality of adjacent meshes. In any case, the light shielding member 9j has, for example, a plate-like shape extending along a plane perpendicular to the paper surface (XZ plane) in FIG. 20, and intersects with each other along a plane substantially parallel to the plane of the illumination pupil. Are arranged as follows. The light-shielding part 9 having the configuration shown in FIG. 20 is obtained, for example, by subjecting a metal plate 91 having a rectangular outer shape to electrical discharge machining, etching, or the like.

  As shown in FIG. 21, for example, when transferring a pattern with a relatively small pitch, a quadrupole pupil intensity distribution 20 (20a to 20d) having a relatively large outer diameter (relatively large illumination NA) is formed. When transferring a pattern having a relatively large pitch, a quadrupole pupil intensity distribution 28 (28a to 28d) having a relatively small outer diameter (relatively small illumination NA) may be formed. In this case, in the first light-shielding member group 9g and the second light-shielding member group 9h of the light-shielding portion 9, by adopting a configuration in which the dimension of the light-shielding member 9j in the optical axis AX direction (Y direction) varies depending on the position, a pair of surfaces In addition to exhibiting the required dimming action for the light sources 20a and 20b, the required dimming action can also be exhibited for the pair of surface light sources 28a and 28b.

  Specifically, in the configuration of FIG. 21, the pair of surface light sources 28a and 28b is larger than the dimension of the light shielding member in the optical axis AX direction of the light shielding member groups 9ga and 9ha arranged facing the pair of surface light sources 20a and 20b. The dimension of the light shielding member in the optical axis AX direction in the light shielding member groups 9gb and 9hb arranged to face each other is set smaller. In other words, the dimension of the light shielding member 9j arranged near the optical axis AX in the optical axis AX direction is set smaller than the dimension of the light shielding member 9j arranged away from the optical axis AX in the optical axis AX direction. Has been.

  Alternatively, as shown in FIG. 22, in the first light shielding member group 9g and the second light shielding member group 9h of the light shielding unit 9, by adopting a configuration in which the roughness of the mesh of the light shielding member group varies depending on the position, a pair of surfaces is obtained. In addition to exhibiting the required dimming action for the light sources 20a and 20b, the required dimming action can also be exhibited for the pair of surface light sources 28a and 28b. Specifically, in the configuration of FIG. 22, the light shielding disposed opposite to the pair of surface light sources 28a and 28b rather than the mesh of the light shielding member groups 9gc and 9hc disposed facing the pair of surface light sources 20a and 20b. The mesh of the member groups 9gd and 9hd is set to be coarser. In other words, the mesh of the light shielding member groups 9gd and 9hd disposed near the optical axis AX is set to be coarser than the mesh of the light shielding member groups 9gc and 9hc disposed away from the optical axis AX.

  In the above description, the operational effects of the present invention are described by taking, as an example, modified illumination in which a quadrupole pupil intensity distribution is formed on the illumination pupil, that is, quadrupole illumination. However, the present invention is not limited to quadrupole illumination. For example, annular illumination in which an annular pupil intensity distribution is formed, multipolar illumination in which a multipolar pupil intensity distribution other than quadrupole is formed, and the like. In contrast, it is apparent that the same effects can be obtained by applying the present invention.

  Further, in the above description, the light shielding unit 9 is arranged immediately after the rear focal plane of the micro fly's eye lens 8 or the illumination pupil in the vicinity thereof. However, the present invention is not limited to this, and the light-shielding portion 9 can be disposed immediately before the rear focal plane of the micro fly's eye lens 8 or the illumination pupil in the vicinity thereof. Further, the light is blocked immediately before or immediately after another illumination pupil behind the micro fly's eye lens 8, for example, immediately before or immediately after the illumination pupil between the front lens group 12a and the rear lens group 12b of the imaging optical system 12. The part 9 can also be arranged. In addition, when the light-shielding part 9 is arrange | positioned in the position of an illumination pupil, since the light-shielding part 9 has a dimension along an optical axis direction, it considers that the light-shielding part 9 is arrange | positioned immediately before and after an illumination pupil. Can do.

  As the correction filter 6 in the above description, for example, those disclosed in JP-A-2005-322855 and JP-A-2007-27240 can be referred to. Further, an aperture stop plate 60 shown in FIG. 23 may be used in place of a correction filter having a dense pattern of light-shielding dots for providing a transmittance distribution with different transmittance depending on the light incident position. In FIG. 23, the aperture stop plate 60 includes four openings 61a to 61d formed at positions of a quadrupole pupil intensity distribution formed at the position of the aperture stop plate 60. And the opening parts 61b and 61c are provided with the light-shielding parts 62b and 62c. With this configuration, the light intensity of the light beam passing through the openings 61b and 61c is attenuated, and the pupil intensity distribution for each point in the still exposure region ER on the wafer W is reflected by the light beam passing through the openings 61b and 61c. The formed pupil intensity distribution is uniformly adjusted without depending on the position of each point. The aperture stop plate 60 can be formed by opening an opening in a light-shielding metal plate.

  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. 24 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 24, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the transfer of the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred is performed (step S46: development process). Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step).

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

  FIG. 25 is a flowchart showing manufacturing steps of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 25, 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 exposure apparatus of the above-described embodiment. In this pattern formation process, an exposure process for transferring the pattern to the photoresist layer using the exposure apparatus of the above-described embodiment and development of the plate P to which the pattern is transferred, that is, development of the photoresist layer on the glass substrate are performed. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

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

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

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD, etc.), micromachine, thin film magnetic head, and 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 a step-and-scan type exposure apparatus that scans and exposes the pattern of the mask M on the shot area of the wafer W. However, the present invention is not limited to this, and the present invention can also be applied to a step-and-repeat type exposure apparatus that repeats the operation of collectively exposing the pattern of the mask M to each exposure region of the wafer W.

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

1 Light Source 3 Diffractive Optical Element 4 Afocal Lens 6 Correction Filter 7 Zoom Lens 8 Micro Fly Eye Lens (Optical Integrator)
9 light shielding parts 9a, 9b light shielding member 10 condenser optical system 11 mask blind 12 imaging optical system M mask PL projection optical system AS aperture stop W wafer

Claims (19)

In the illumination optical system that illuminates the illuminated surface with light from the light source,
A distribution forming optical system having an optical integrator and forming a pupil intensity distribution in an illumination pupil on the rear side of the optical integrator;
Comprising at least two light shielding members arranged at positions immediately before or after the illumination pupil and extending so as to intersect each other along a plane substantially parallel to the plane of the illumination pupil;
The at least two light shielding members are configured such that a light reduction rate of the light directed to one point on the irradiated surface by the at least two light shielding members increases from the center to the periphery of the irradiated surface. Characteristic illumination optical system. The illumination optical system according to claim 1, wherein each of the at least two light shielding members has a plate shape. The optical integrator has an elongated rectangular unit wavefront dividing surface along a predetermined direction,
3. The illumination optical system according to claim 1, wherein the at least two light shielding members are configured such that the attenuation rate increases from a center to a periphery along the predetermined direction. The optical integrator has an elongated rectangular unit wavefront dividing surface along a predetermined direction,
The at least two light shielding members are positioned so as to act on light from a pair of regions spaced apart in a direction orthogonal to the predetermined direction across the optical axis of the illumination optical system in the illumination pupil. The illumination optical system according to any one of claims 1 to 3. 5. The illumination optical system according to claim 4, wherein the at least two light shielding members are arranged substantially symmetrically with respect to an axis extending in a direction orthogonal to the predetermined direction through the optical axis. In the illumination optical system that illuminates the illuminated surface with light from the light source,
A distribution forming optical system having an optical integrator and forming a pupil intensity distribution in an illumination pupil on the rear side of the optical integrator;
Comprising at least two light shielding members disposed in a position immediately before or after the illumination pupil and having a mesh shape along a plane substantially parallel to the plane of the illumination pupil ;
The at least two light shielding members are configured such that a light reduction rate of the light directed to one point on the irradiated surface by the at least two light shielding members increases from the center to the periphery of the irradiated surface. Characteristic illumination optical system. The at least two light shielding members are arranged so as to act on light from one of the pair of regions and have a mesh-like shape, and the other of the pair of regions. The illumination optical system according to claim 6, further comprising: a second light-shielding member group that is arranged so as to act on light from the first region and has a mesh shape. The illumination optical system according to claim 7, wherein the first light shielding member group and the second light shielding member group are configured substantially symmetrically with respect to an axis extending through the optical axis in the predetermined direction. The illumination optical system according to claim 7 or 8, wherein in the first light shielding member group and the second light shielding member group, the dimension of the light shielding member in the optical axis direction varies depending on the position. 10. The dimension in the optical axis direction of the light shielding member disposed near the optical axis is smaller than the dimension in the optical axis direction of the light shielding member disposed away from the optical axis. The illumination optical system described in 1. 9. The illumination optical system according to claim 7, wherein in the first light shielding member group and the second light shielding member group, the mesh of the light shielding member group varies depending on the position. The illumination optical system according to claim 11, wherein the mesh of the light shielding member group disposed near the optical axis is coarser than the mesh of the light shielding member group disposed away from the optical axis. The light intensity distribution adjusting unit for changing the illuminance distribution on the irradiated surface or the shape of the illumination area formed on the irradiated surface, further comprising: Lighting optics. The illumination optical system according to claim 13, wherein the light amount distribution adjusting unit corrects an influence on the light amount distribution on the irradiated surface by the light shielding member. 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. 15. The illumination optical system according to any one of 1 to 14. An exposure apparatus comprising the illumination optical system according to any one of claims 1 to 15 for illuminating a predetermined pattern, and exposing the predetermined pattern onto a photosensitive substrate. A projection optical system for forming an image of the predetermined pattern on the photosensitive substrate; and moving the predetermined pattern and the photosensitive substrate relative to the projection optical system along a scanning direction to The exposure apparatus according to claim 16, wherein the pattern is exposed by projection onto the photosensitive substrate. The exposure apparatus according to claim 17, wherein the predetermined direction in the optical integrator corresponds to a direction orthogonal to the scanning direction. An exposure step of exposing the predetermined pattern to the photosensitive substrate using the exposure apparatus according to any one of claims 16 to 18,
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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