WO2012137699A1 - Appareil optique, appareil d'exposition, et procédé de fabrication d'un dispositif - Google Patents

Appareil optique, appareil d'exposition, et procédé de fabrication d'un dispositif Download PDF

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Publication number
WO2012137699A1
WO2012137699A1 PCT/JP2012/058817 JP2012058817W WO2012137699A1 WO 2012137699 A1 WO2012137699 A1 WO 2012137699A1 JP 2012058817 W JP2012058817 W JP 2012058817W WO 2012137699 A1 WO2012137699 A1 WO 2012137699A1
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Prior art keywords
optical axis
optical
pupil
optical system
peripheral edge
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PCT/JP2012/058817
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English (en)
Japanese (ja)
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白石　雅之
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株式会社ニコン
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
    • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
    • G02B17/0647—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using more than three curved mirrors
    • G02B17/0663—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using more than three curved mirrors off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70216—Mask projection systems
    • G03F7/70233—Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems

Definitions

  • the present invention relates to an optical apparatus, an exposure apparatus, and a device manufacturing method. More specifically, the present invention relates to an exposure apparatus that transfers a circuit pattern on a mask onto a photosensitive substrate by using a plurality of reflecting mirrors using, for example, EUV light.
  • an exposure apparatus When manufacturing a device such as a semiconductor element, an exposure apparatus is used that transfers a circuit pattern formed on a mask (reticle) onto a photosensitive substrate (for example, a wafer coated with a resist) via a projection optical system.
  • a projection optical system of an exposure apparatus is a refractive optical system composed of a plurality of light transmitting members (lenses and the like), and its pupil (exit pupil) and all optical elements are rotationally symmetric with respect to the optical axis. Therefore, the aperture stop is disposed at the position of the pupil in a posture parallel to the mask pattern surface and the wafer transfer surface, and the aperture stop (light transmission portion) of the aperture stop is formed in a circular shape centering on the optical axis. preferable.
  • EUV exposure apparatus an exposure apparatus using EUV (Extreme UltraViolet) light having a wavelength of about 5 to 40 nm
  • EUV exposure apparatus When EUV light is used as the exposure light, there is no transmissive optical material and refractive optical material that can be used. Therefore, a reflective mask is used, and a reflective optical system (an optical system composed only of a reflective member) is used as a projection optical system. Will be used.
  • a two-mirror type reflection optical system composed of a convex reflecting mirror having a central opening and a concave reflecting mirror having a central opening has been proposed.
  • this two-mirror projection optical system an effective imaging region having an outer shape centered on the optical axis can be obtained.
  • the mask pattern surface and the wafer transfer surface are inclined with respect to the surface orthogonal to the optical axis, the optical system is rotationally symmetric with respect to the optical axis. Therefore, the aperture stop and the central shielding plate have a circular shape centered on the optical axis, and are arranged along a plane orthogonal to the optical axis.
  • a six-mirror reflective optical system composed of six (or more) reflecting mirrors has been proposed.
  • the effective imaging region is formed away from the optical axis, and the optical system is rotationally asymmetric with respect to the optical axis.
  • the direction of the light beam passing through the pupil of the optical system is inclined with respect to the optical axis by the amount that the effective imaging region is away from the optical axis. Therefore, the optimum shape of the aperture of the aperture stop is not a circle parallel to the mask pattern surface and the wafer transfer surface, but a three-dimensional closed curve connecting the minimum circles of confusion of the light beam for each direction of the pupil (Patent Document 1). See).
  • a projection optical system having a large image-side numerical aperture is required in order to improve resolution.
  • a central shielding type that shields the center of the pupil is used.
  • a projection optical system is employed. In this case, if a simple planar circular or elliptical plate is used as the central shielding plate as in the prior art, the shapes of the pupils are different from each other at each point (each image height) in the effective imaging region. Good optical performance cannot be ensured.
  • the present invention has been made in view of the above-described problems, and is an optical apparatus that includes a central shielding type projection optical system having a plurality of reflecting mirrors, and that can ensure good optical performance.
  • the purpose is to provide.
  • the optical system has a plurality of reflecting mirrors disposed between the first surface and the second surface, and the image of the first surface is converted into the first surface.
  • a diaphragm member that defines the outer shape of the luminous flux;
  • a shielding part for shielding a part of the luminous flux
  • the diaphragm member has an inner peripheral edge having a different height in the optical axis direction of the optical system,
  • the shielding unit has an outer peripheral edge having different heights in the optical axis direction.
  • an illumination system for illuminating a predetermined pattern installed on the first surface with light from a light source, and a photosensitive substrate installed on the second surface with the predetermined pattern.
  • An exposure apparatus comprising: an optical apparatus according to a first embodiment for projecting.
  • the exposure apparatus of the second embodiment exposing the predetermined pattern to the photosensitive substrate; Developing the photosensitive substrate having the predetermined pattern transferred thereon, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the photosensitive substrate; And processing the surface of the photosensitive substrate through the mask layer.
  • a device manufacturing method is provided.
  • the optical apparatus according to the present invention is an optical apparatus having a central shielding type projection optical system having a plurality of reflecting mirrors, and has a substantially uniform pupil shape at each point in the effective imaging region, and has good optics. Performance can be ensured. Further, in the exposure apparatus of the present invention, an optical apparatus having good optical performance can be used and, for example, EUV light can be used as exposure light to perform good projection exposure with high resolution.
  • the central shielding type projection optical system that shields the center of the pupil is adopted as a projection optical system capable of improving the resolution.
  • the first mirror from the wafer side (the sixth reflecting mirror M6 of this embodiment to be described later) is considered when going back the optical path from the wafer to the mask side.
  • the diameter of the MU increases according to the numerical aperture (NA) of the light beam incident on the wafer, and the second mirror from the wafer side (corresponding to the fifth reflecting mirror M5 in this embodiment) MP avoids the large mirror MU.
  • NA numerical aperture
  • MP avoids the large mirror MU.
  • the central shielding type projection optical system is adopted to allow the central shielding of the pupil
  • the light beam received by the first mirror MU from the wafer side is reflected on the wafer side when considering the optical path back from the wafer to the mask side.
  • the light flux can be traced back so as to pass through the central opening of the mirror MU when tracing to the third mirror MM via the second mirror MP.
  • the central opening portion of the mirror MU corresponds to the central shielding region of the pupil.
  • an optical design is facilitated by forming a ring-shaped pupil by providing a shielding region at the center of the pupil.
  • the outer periphery of the pupil is large according to the numerical aperture on the image side, but there is an ineffective portion at the center of the pupil, so although the outer periphery of the pupil is large and the whole is effective, the large image A fine pattern can be accurately transferred with high resolution according to the side numerical aperture.
  • the shielding area at the center of the pupil is preferably as small as possible and should be kept to the minimum necessary size.
  • the shielding area at the center is irregular and the shape of the shielding area is different for each point in the effective imaging area.
  • the central shielding plate is a small circular flat plate.
  • a support bar for holding is attached to the central shielding plate, and is supported by members on the outer periphery.
  • the support bar is attached along an orientation having a small influence on the resolution (imaging).
  • imaging imaging
  • a part of the diffracted light is unintentionally shielded by the support bar, so the support bar that is as thin as possible is used.
  • a central shielding plate obtained by simply cutting a flat plate into a circle or an ellipse is merely arranged in the vicinity of the pupil.
  • the optical presence of the central shielding plate defines (forms) the inner periphery of the annular pupil. Therefore, it is preferable that the central shielding plate defines the inner periphery of the pupil in a shape corresponding to the predetermined NA so that the aperture stop defines the outer periphery of the pupil in a shape corresponding to the predetermined NA.
  • the projection optical system of the EUV exposure apparatus has an inner peripheral edge having a different height in the optical axis direction of the projection optical system, and a diaphragm member that defines the outer shape of the light beam, and the projection optical system And a shielding portion that shields a part of the light beam and has outer peripheral edges having different heights in the optical axis direction.
  • the inner peripheral edge of the diaphragm member has a height in the optical axis direction of the projection optical system that changes along the direction of the pupil, and the outer peripheral edge of the shielding portion is the height in the optical axis direction of the projection optical system.
  • the shape of the aperture of the aperture stop i.e., the inner peripheral edge of the aperture stop (aperture member) is the minimum confusion of the light flux having a predetermined NA (first numerical aperture greater than the second numerical aperture) for each direction of the pupil. It is the same as that defined by a three-dimensional closed curve connecting circles.
  • the curve that defines the outer peripheral edge of the shielding portion is defined by a three-dimensional closed curve as in the case of the inner peripheral edge of the aperture stop.
  • NA 0.6; first numerical aperture
  • a light beam having the same NA that is emitted from each point in the effective imaging region does not intersect at the same point in the vicinity of the pupil, but becomes a light beam having a certain minimum circle of confusion.
  • the height of this minimum circle of confusion varies depending on the orientation of the pupil, and is particularly greatly distorted in the sagittal direction and the meridional direction of NA. That is, instead of simply drawing an ellipse on a plane or drawing a curve on a plane that is not parallel to the mask pattern surface and the wafer transfer surface, each point in the effective imaging region has the same NA in each direction.
  • the closed curve that connects the height of the minimum circle of confusion of the luminous flux produced by the scattered light beam for each direction of the pupil is not on the same plane.
  • FIG. 1 is a diagram schematically showing how a light beam passes through a pupil of a projection optical system of an EUV exposure apparatus.
  • the projection optical system has, for example, a first reflecting mirror M1, a second reflecting mirror M2, a third reflecting mirror M3, a fourth reflecting mirror M4, and a fifth reflecting mirror in the optical order from the mask toward the wafer. It is assumed that it is composed of six mirrors, M5 and a sixth reflecting mirror M6. It is assumed that the first pupil is in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2, and the second pupil is in the optical path from the fifth reflecting mirror M5 to the sixth reflecting mirror M6. is doing.
  • the light from the mask is reflected by the first reflecting mirror M1, and the light beam travels from the bottom (from the wafer side) to the top (to the mask side) from the first reflecting mirror M1 toward the second reflecting mirror M2. pass. Further, light from the fourth reflecting mirror M4 (corresponding to the third mirror MM from the wafer side) is reflected by the fifth reflecting mirror M5 (corresponding to the second mirror MP from the wafer side), and from the fifth reflecting mirror M5. The light beam passes from the bottom to the top toward the sixth reflecting mirror M6 (corresponding to the first mirror MU from the wafer side).
  • the Z axis is set parallel to the optical axis of the projection optical system
  • the Y axis is set parallel to the scanning direction (scanning direction) of the mask and wafer
  • the X axis is orthogonal to the scanning direction. It is set parallel to the scanning orthogonal direction (non-scanning direction).
  • the pupil is not necessarily in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2 and in the optical path from the fifth reflecting mirror M5 to the sixth reflecting mirror M6.
  • the light beam passing through the pupil does not always go from the bottom to the top.
  • the principal ray 21 is a ray whose NA is equal to 0, and with the point 231 where the ray having 0 NA emitted from each point in the effective imaging region converges most in the vicinity of the pupil, A representative height in the optical axis direction of the pupil of the principal ray 21, that is, a reference height is used. Due to the characteristics of the optical system, light rays of the same NA that are emitted from each point in the effective imaging region do not converge to one point in the vicinity of the pupil, and a minimum circle of confusion is obtained.
  • rays of the same NA emitted from each point in the effective imaging region in each of the azimuths are near the pupil.
  • the heights are as shown by reference numerals 232, 233, 234, and 235, respectively.
  • a circle indicated by reference numeral 22 in FIG. 1 represents a predetermined NA at the reference height 231.
  • the projection optical system of a typical EUV exposure apparatus In the design example (an example in which the effective imaging region is separated from the optical axis and symmetric with respect to the Y axis), the height 232 of the minimum circle of confusion of a predetermined NA light flux passing through the + Y direction of the pupil in the optical axis direction was found to be on the ⁇ Z direction side with respect to the reference height 231.
  • the heights 233 and 234 in the optical axis direction of the minimum circle of confusion of a predetermined NA light beam passing through the ⁇ X direction and the + X direction of the pupil are on the + Z direction side of the reference height 231.
  • the difference between the height 232 and the heights 233 and 234 is the height 233 and 234. It should match the difference from height 235. However, in practice, the difference between the height 232 and the heights 233 and 234 is 4 mm, the difference between the heights 233 and 234 and the height 235 is 5 mm, and the difference between the two is different. This is because when a contour curve obtained by connecting the heights of the minimum circles of confusion of a light beam having a predetermined NA with respect to each direction of the pupil is projected from the X direction, the projection of the contour is not a straight line but a curved line.
  • the inner peripheral edge of the aperture stop is not on the same plane in order to improve the optical performance.
  • the aperture stop that defines the outer shape (outer periphery) of the light beam having the first numerical aperture that passes through the pupil, but also a part of the light beam that passes through the pupil, that is, the second numerical aperture smaller than the first numerical aperture. The same holds true for the shielding part that shields the luminous flux.
  • the line connecting the positions in the optical axis direction of the minimum circle of confusion formed by the light beams corresponding to “the same NA” in each direction of the pupil is a three-dimensional closed curve that is not on the same plane. It merely describes drawing, and does not limit whether the light beam corresponding to “the same NA” is a light beam that defines the outer periphery of the pupil or a light beam that defines the inner periphery of the pupil.
  • FIG. 2 is a drawing schematically showing a configuration of the exposure apparatus according to the embodiment of the present invention.
  • FIG. 3 is a diagram showing the positional relationship between the arc-shaped effective imaging region formed on the wafer and the optical axis. 2, the Z axis along the optical axis AX direction of the projection optical system PO, that is, the normal direction of the exposure surface (transfer surface) of the wafer W that is a photosensitive substrate, and the paper surface of FIG.
  • the Y axis is set in the direction parallel to the X axis, and the X axis is set in the direction perpendicular to the paper surface of FIG.
  • the 2 includes, for example, a laser plasma X-ray source as a light source LS for supplying exposure light.
  • a laser plasma X-ray source as a light source LS for supplying exposure light.
  • a discharge plasma light source or another X-ray source can be used.
  • the light emitted from the light source LS enters the illumination optical system IL via a wavelength selection filter (not shown) arranged as necessary.
  • the wavelength selection filter has a characteristic of selectively transmitting only EUV light having a predetermined wavelength (for example, 13.5 nm) from light supplied from the light source LS and blocking transmission of other wavelength light.
  • the EUV light that has passed through the wavelength selection filter passes through the collimator optical system 1 having the shape of a concave reflecting mirror, becomes a substantially parallel light beam, and is guided to an optical integrator 2 that includes a pair of fly-eye mirrors 2a and 2b.
  • the first fly-eye mirror 2a is configured by, for example, arranging a large number of concave mirror elements having an arcuate outer shape vertically and horizontally and densely.
  • the second fly's eye mirror 2b is configured by, for example, arranging a large number of concave mirror elements having a rectangular shape close to a square shape vertically and horizontally and densely.
  • a substantial surface light source having a predetermined shape is formed in the vicinity of the exit surface of the optical integrator 2, that is, in the vicinity of the reflection surface of the second fly-eye mirror 2b (the position of the illumination pupil).
  • the light from the substantial surface light source passes through the condenser optical system 3 having a concave reflecting mirror shape and the deflecting member 4 having a planar reflecting surface, and is then emitted from the illumination optical system IL (1 to 4).
  • the position of the illumination pupil of the illumination optical system IL where a substantial surface light source is formed is the position of the entrance pupil of the projection optical system PO or a position optically conjugate with the entrance pupil of the projection optical system PO.
  • the light emitted from the illumination optical system IL passes through the arc-shaped opening (light transmitting portion) of a field stop (not shown) disposed substantially parallel to and in close proximity to the reflective mask M.
  • An arcuate illumination area is formed on the top.
  • the light source LS and the illumination optical system IL constitute an illumination system for Koehler illumination of the mask M provided with a predetermined pattern.
  • the mask M is held by a mask stage MS that can move along the Y direction so that the pattern surface extends along the XY plane.
  • the movement of the mask stage MS is measured by a laser interferometer (not shown).
  • a laser interferometer not shown.
  • an arcuate illumination region symmetric with respect to the Y axis is formed.
  • the light from the illuminated mask M forms a pattern image of the mask M on the wafer W, which is a photosensitive substrate, via the projection optical system PO.
  • an arc-shaped effective imaging region ER that is symmetric with respect to the Y axis is formed.
  • an arc-shaped effective imaging region ER is formed in contact with the image circle IF in a circular region (image circle) IF centered on the optical axis AX.
  • the arc-shaped effective imaging region ER is a part of a ring-shaped region centered on the optical axis AX.
  • an arcuate illumination area symmetric with respect to the Y axis is formed so as to optically correspond to the arcuate effective imaging area ER.
  • the wafer W is held by a wafer stage WS that can move two-dimensionally along the X and Y directions such that the exposure surface extends along the XY plane.
  • the movement of the wafer stage WS is measured by a laser interferometer (not shown) as in the mask stage MS.
  • scan exposure scan exposure
  • scan exposure is performed while moving the mask stage MS and the wafer stage WS along the Y direction, that is, while relatively moving the mask M and the wafer W along the Y direction with respect to the projection optical system PO.
  • the pattern of the mask M is transferred to one exposure region of the wafer W.
  • the moving speed of the wafer stage WS is set to 1/4 of the moving speed of the mask stage MS, and synchronous scanning is performed. Further, the pattern of the mask M is sequentially transferred to each exposure region of the wafer W by repeating the scanning exposure while moving the wafer stage WS two-dimensionally along the X direction and the Y direction.
  • the projection optical system PO forms a first intermediate image of a pattern at a position optically conjugate with the pattern surface of the mask M along a single optical axis AX extending linearly.
  • 1 reflective optical system G1 and a second reflective optical system G2 for forming a final reduced image (intermediate image) of the pattern of the mask M on the wafer W. That is, a surface optically conjugate with the pattern surface of the mask M is formed in the optical path between the first reflection optical system G1 and the second reflection optical system G2.
  • the first reflective optical system G1 includes a first reflecting mirror M1 having a concave reflecting surface, a second reflecting mirror M2 having a concave reflecting surface, and a convex reflecting surface in the order of incidence of light from the mask M. And a fourth reflecting mirror M4 having a concave reflecting surface.
  • the second reflecting optical system G2 is configured by a fifth reflecting mirror M5 having a convex reflecting surface and a sixth reflecting mirror M6 having a concave reflecting surface in the order of incidence of light from the fourth reflecting mirror M4. ing.
  • Openings M5a and M6a are provided at the centers of the reflecting surfaces of the fifth reflecting mirror M5 and the sixth reflecting mirror M6, respectively.
  • An aperture stop AS and a shielding part SH are provided in the vicinity of the pupil in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2. There is no aperture stop other than the aperture stop AS in the optical path of the projection optical system PO, and the numerical aperture of the projection optical system PO is determined by the restriction of the light flux by the aperture stop AS.
  • the projection optical system PO light from the illumination area on the arc away from the optical axis AX on the pattern surface (first surface) of the mask M is reflected by the concave reflecting surface of the first reflecting mirror M1 and the second reflecting mirror M2. Are sequentially reflected by the concave reflecting surface, the convex reflecting surface of the third reflecting mirror M3, and the concave reflecting surface of the fourth reflecting mirror M4 to form an intermediate image of the mask pattern.
  • the light from the intermediate image formed through the first reflecting optical system G1 passes through the opening M6a of the sixth reflecting mirror M6 and is reflected by the convex reflecting surface of the fifth reflecting mirror M5. 6 is incident on the concave reflecting surface of the reflecting mirror M6.
  • the light reflected by the sixth reflecting mirror M6 passes through the opening M5a of the fifth reflecting mirror M5, and then, on the surface (second surface) of the wafer W, the arc-shaped effective imaging region ER separated from the optical axis AX. Then, a reduced image of the mask pattern is formed.
  • the reflecting surfaces of all the reflecting mirrors M1 to M6 are formed in a rotationally symmetric surface shape with respect to the optical axis AX.
  • the projection optical system PO is an optical system telecentric on the wafer side (image side). In other words, the chief ray reaching each point in the effective imaging region ER of the projection optical system PO is substantially perpendicular to the image plane. With this configuration, good image formation is possible even if the wafer W is uneven within the depth of focus of the projection optical system PO.
  • FIG. 4 and 5 are diagrams schematically showing a state in which the light beam passes through the pupil of the projection optical system of the exposure apparatus according to the present embodiment.
  • FIG. 6 is a cross-sectional view of the aperture stop and the shielding unit arranged in the vicinity of the pupil of the projection optical system. 4 to 6, as in the case of FIG. 1, the Z axis of the XYZ orthogonal coordinate system is set parallel to the optical axis AX of the projection optical system PO, and the Y axis is parallel to the scanning directions of the mask M and the wafer W. And the X axis is set parallel to the scanning orthogonal direction. Further, it is assumed that the optical axis AX extends in the vertical direction, the XY plane is a horizontal plane, and the projection optical system PO is designed symmetrically with respect to the Y axis.
  • an aperture stop (aperture member) AS that defines the shape is provided. 4 and 5, reference numeral 12 indicates the principal ray of the light beam 11 passing through the pupil.
  • the aperture stop AS is formed by providing an opening portion Asa having a predetermined shape on a metal plate previously formed into a required curved shape.
  • the aperture stop AS is formed by forming a predetermined shape of an opening portion Asa on a flat metal plate and then forming the aperture stop ASa into a required curved surface.
  • the inner peripheral edge ASb of the aperture stop AS (that is, the contour of the aperture portion Asa) is defined by a three-dimensional closed curve connecting the minimum circles of confusion of the first numerical aperture NA1 with respect to each direction of the pupil, and is in the direction of the optical axis AX.
  • the height in the (Z direction) changes in a curved line along the direction of the pupil.
  • the first numerical aperture NA1 is an image-side numerical aperture corresponding to the outer shape of the light beam 11 to be defined by the aperture stop AS when passing through the pupil.
  • a region where a light beam corresponding to the first numerical aperture NA1 passes through the pupil is schematically indicated by a circle 13.
  • a shielding part SH that shields a part of the light beam 11 is provided.
  • the shielding part SH is formed by giving a predetermined outer shape (contour) to a metal plate that has been previously formed into a required curved surface shape.
  • shielding part SH is formed by shape
  • the outer peripheral edge SHa of the shielding part SH is defined by a three-dimensional closed curve connecting minimum circles of confusion formed by the light flux having the second numerical aperture NA2 smaller than the first numerical aperture NA1 in each direction of the pupil, and the direction of the optical axis AX The height of the curve changes along the direction of the pupil.
  • the second numerical aperture NA2 is an image-side numerical aperture corresponding to the outer shape of the central portion of the light beam 11 to be shielded by the shielding portion SH when passing through the pupil.
  • a region where a light beam corresponding to the second numerical aperture NA2 passes through the pupil is schematically indicated by a circle 14.
  • the shielding part SH is held at a required position from an outer peripheral member such as a lens barrel (not shown) by a support bar (not shown), for example.
  • the support bar of the shielding part SH is made of a thin member that minimizes the influence on the optical performance of the projection optical system PO, and the direction in which the main diffracted light will pass (X-axis direction, Y-axis direction, etc.) It is arranged along the direction avoiding.
  • the form of the support bar may be a cantilever system or a double-support system, and it is only necessary that the outer peripheral edge SHa of the supported shielding part SH is disposed at a required position (optically optimal position).
  • the light beam that has passed through the aperture stop AS and the shielding part SH has an annular shape. Further, as clearly shown in FIG. 6, the aperture stop AS and the shielding portion SH are arranged at different positions along the optical axis AX. Note that a curved line 15 indicated by a broken line in FIG. 6 indicates an envelope surface (three-dimensional curved surface) of pupils that collect equal NA lines (three-dimensional curve).
  • the positions of the pair of edge points facing the Y direction across the optical axis AX are different from each other, and the pair of the edge points facing the X direction across the optical axis AX are different.
  • the positions of the edge points in the optical axis AX direction are the same.
  • the inner peripheral edge ASb of the aperture stop AS provided in the vicinity of the pupil in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2 of the projection optical system PO corresponds to each pupil. It is defined by a three-dimensional closed curve connecting the minimum circle of confusion of the light beam having the first numerical aperture NA1 with respect to the azimuth. Further, the outer peripheral edge SHa of the shielding portion SH provided in the vicinity of the pupil in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2 has a light beam having a second numerical aperture NA2 smaller than the first numerical aperture NA1. It is specified by a three-dimensional closed curve connecting the minimum circles of confusion created in each direction.
  • the projection optical system PO of the present embodiment due to the cooperative action of the aperture stop AS and the shielding portion SH, the shape of the annular pupil is substantially uniform for each point in the effective imaging region ER, As a result, good optical performance can be ensured.
  • the projection optical system PO having good optical performance is used and EUV light is used as exposure light, it is possible to perform good projection exposure with high resolution.
  • the projection optical system PO is configured by the six reflecting mirrors M1 to M6, and the four reflecting mirrors M1 to M4 form the first imaging optical system (first reflecting optical system G1). Two reflecting mirrors M5 and M6 form a second imaging optical system (second reflecting optical system G2).
  • the present invention is not limited to this, and various forms are possible for the number of mirrors, the arrangement, the number of times of imaging, and the like.
  • the reflecting surfaces of the reflecting mirrors M1 to M6 of the projection optical system PO are formed in a rotationally symmetric surface shape.
  • the present invention is not limited to this, and the surface shape is not rotationally symmetric. May be.
  • both the aperture stop AS and the shielding part SH are provided in the vicinity of the pupil in the optical path from the first reflecting mirror M1 to the second reflecting mirror M2 of the projection optical system PO.
  • both the aperture stop AS and the shielding part SH may be provided in the vicinity of the pupil in the optical path from the fifth reflecting mirror M5 to the sixth reflecting mirror M6.
  • the aperture stop AS or the shielding part SH
  • the shielding part SH or the aperture stop AS
  • You may provide in the pupil vicinity in the optical path which leads to 6 reflector M6.
  • EUV light having a wavelength of 13.5 nm is used as an example.
  • the present invention is not limited to this.
  • EUV light having a wavelength of about 5 to 40 nm or other appropriate The present invention can be similarly applied to a projection optical system and an exposure apparatus that use light of various wavelengths.
  • variable pattern forming apparatus that forms a predetermined pattern based on predetermined electronic data can be used instead of a mask.
  • a spatial light modulation element including a plurality of reflection elements driven based on predetermined electronic data can be used.
  • An exposure apparatus using a spatial light modulator is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285, and US Patent Publication No. 2007/0296936 corresponding thereto.
  • a transmissive spatial light modulator may be used, or a self-luminous image display element may be used.
  • the exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done.
  • various optical systems are adjusted to achieve optical accuracy
  • various mechanical systems are adjusted to achieve mechanical accuracy
  • various electrical systems are Adjustments are made to achieve electrical accuracy.
  • the assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus.
  • the exposure apparatus may be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.
  • FIG. 7 is a flowchart showing a semiconductor device manufacturing process.
  • a metal film is vapor-deposited on a wafer W to be a substrate of the semiconductor device (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film.
  • 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).
  • step S48 processing step.
  • 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.
  • 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.
  • the exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as a photosensitive substrate.
  • a laser plasma X-ray source is used as a light source for supplying EUV light.
  • the present invention is not limited to this, and for example, synchrotron radiation (SOR) light is used as EUV light. You can also.
  • the present invention is applied to the projection optical system of the exposure apparatus.
  • the present invention is not limited to this, and a plurality of elements disposed between the first surface and the second surface are not limited thereto.
  • the present invention can be similarly applied to an optical device that includes an optical system having a reflecting mirror and forms an image of the first surface on the second surface.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

L'invention concerne un appareil optique équipé d'un système optique de projection du type écran central comprenant une pluralité de miroirs réfléchissants, dans lequel la forme d'une pupille est grossièrement uniforme en chacun des points à l'intérieur d'une zone d'imagerie effective, et avec lequel de bonnes performances optiques peuvent être obtenues. Ledit appareil optique, qui est pourvu d'un système optique comprenant une pluralité de miroirs réfléchissants disposés entre une première face et une deuxième face, et qui forme une image de la première face sur la deuxième face, est également équipé d'un élément de diaphragme iris pour imposer la forme externe du flux lumineux, et d'une section d'écran pour couper une partie du flux lumineux. L'élément de diaphragme iris comprend un bord circonférentiel interne qui présente des hauteurs variables dans la direction de l'axe optique du système optique, et la section d'écran comprend un bord circonférentiel externe qui présente des hauteurs variables dans la direction de l'axe optique.
PCT/JP2012/058817 2011-04-05 2012-04-02 Appareil optique, appareil d'exposition, et procédé de fabrication d'un dispositif WO2012137699A1 (fr)

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JP2011-083251 2011-04-05

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DE102014223811A1 (de) 2014-11-21 2016-05-25 Carl Zeiss Smt Gmbh Abbildende Optik für die EUV-Projektionslithographie

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JP2001185480A (ja) * 1999-10-15 2001-07-06 Nikon Corp 投影光学系及び該光学系を備える投影露光装置
JP2004246343A (ja) * 2003-01-21 2004-09-02 Nikon Corp 反射光学系及び露光装置
JP2005086148A (ja) * 2003-09-11 2005-03-31 Nikon Corp 極端紫外線光学系及び露光装置
WO2006001291A1 (fr) * 2004-06-23 2006-01-05 Nikon Corporation Système optique de projection, dispositif d'exposition et méthode d'exposition
WO2009121541A1 (fr) * 2008-04-04 2009-10-08 Carl Zeiss Smt Ag Dispositif d'éclairage microlithographique par projection, et dispositif d'inspection d'une surface d'un substrat
WO2010032753A1 (fr) * 2008-09-18 2010-03-25 株式会社ニコン Diaphragme, système optique, appareil d'exposition et procédé de fabrication de dispositif électronique

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JP2001185480A (ja) * 1999-10-15 2001-07-06 Nikon Corp 投影光学系及び該光学系を備える投影露光装置
JP2004246343A (ja) * 2003-01-21 2004-09-02 Nikon Corp 反射光学系及び露光装置
JP2005086148A (ja) * 2003-09-11 2005-03-31 Nikon Corp 極端紫外線光学系及び露光装置
WO2006001291A1 (fr) * 2004-06-23 2006-01-05 Nikon Corporation Système optique de projection, dispositif d'exposition et méthode d'exposition
WO2009121541A1 (fr) * 2008-04-04 2009-10-08 Carl Zeiss Smt Ag Dispositif d'éclairage microlithographique par projection, et dispositif d'inspection d'une surface d'un substrat
WO2010032753A1 (fr) * 2008-09-18 2010-03-25 株式会社ニコン Diaphragme, système optique, appareil d'exposition et procédé de fabrication de dispositif électronique

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Publication number Priority date Publication date Assignee Title
DE102014223811A1 (de) 2014-11-21 2016-05-25 Carl Zeiss Smt Gmbh Abbildende Optik für die EUV-Projektionslithographie
EP3023824A1 (fr) 2014-11-21 2016-05-25 Carl Zeiss SMT GmbH Systeme catoptrique d'imagerie pour projection en lithographie euv
US9625827B2 (en) 2014-11-21 2017-04-18 Carl Zeiss Smt Gmbh Imaging optical unit for EUV projection lithography
US9835953B2 (en) 2014-11-21 2017-12-05 Carl Zeiss Smt Gmbh Imaging optical unit for EUV projection lithography
US10191386B2 (en) 2014-11-21 2019-01-29 Carl Zeiss Smt Gmbh Imaging optical unit for EUV projection lithography

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