JP2007266511A - Optical system, exposure apparatus, and adjustment method of optical characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure technology capable of correcting a non rotational symmetry aberration in a reproducible state without the possibility of causing a damage to an optical member. <P>SOLUTION: A projection optical system with a concave mirror 22 includes: a probe 27a arranged in a state that can be pressed into contact with the concave mirror 22; a coarse adjustment mechanism wherein a coarse adjustment micrometer 26A drives a plate spring 28a to drive the probe 27a in a direction pressed into contact with a projection 22a of the concave mirror 22; and an inching mechanism that controls a force of the probe 27a applied to the projection 22a by using an inching micrometer 26B to drive the plate spring 28b, after the probe 27a is pressed into contact with the projection 22a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical system having an optical member, and can be applied to, for example, a projection optical system of an exposure apparatus. Further, the present invention relates to an exposure technique using the optical system and a technique for adjusting optical characteristics.

For example, in a lithography process, which is one of the manufacturing processes of a semiconductor device, a pattern formed on a reticle (or photomask or the like) is applied on a wafer (or glass plate or the like) coated with a resist via a projection optical system. An exposure apparatus such as a stepper or a scanning stepper is used to transfer the image onto the surface.
The projection optical system mounted on these exposure apparatuses is assembled and adjusted so that various aberrations are within a predetermined allowable range. At this time, for example, even if rotational aberrations such as distortion aberration and magnification error and low-order aberration components remain, these aberrations are not affected by normal imaging characteristic correction mechanisms (for example, mounted on the projection optical system) It can be corrected by a mechanism that controls the position and tilt angle of a predetermined lens in the optical axis direction. On the other hand, when a non-rotationally symmetric aberration component such as astigmatism on the optical axis (hereinafter referred to as “center astigmatism”) remains, The correction is difficult.

In order to correct such non-rotationally symmetric aberration components, a mechanism has been proposed in which non-rotationally symmetric stress is applied from the side surface to a predetermined lens in the projection optical system (for example, a patent). Reference 1). In order to correct non-rotationally symmetric aberration components, a mechanism has also been proposed in which a predetermined lens is housed in a deformable ring and the lens is deformed via the ring by an external force. (For example, refer to Patent Document 2).
Special Table 2002-519843 JP 2000-195788 A

  A conventional correction mechanism for non-rotationally symmetric aberration components such as a center ass has deformed a predetermined lens by a non-rotationally symmetric stress from the side surface. Therefore, when the stress is increased, the lens may be damaged. In addition, since it is difficult to accurately predict the deformation state of the lens due to the stress from the side surface, it is difficult to perform aberration correction in a reproducible state.

Recently, a catadioptric system and a reflection system including a mirror such as a concave mirror have been developed as a projection optical system, but the correction target by the conventional correction mechanism is a lens, and the mirror is not a correction target. .
In view of such problems, the present invention provides an optical system capable of correcting non-rotationally symmetric aberrations without causing damage to optical members such as lenses and mirrors and in a reproducible state. With the goal.

  It is another object of the present invention to provide an exposure technique that can correct non-rotationally symmetric aberration in a reproducible state using the optical system.

  The optical system according to the present invention is an optical system having an optical member (22). The optical system includes an abutting member (27a) that is disposed away from the optical member and can abut against the optical member, and the abutting member is optical A first drive mechanism (28a, 26A) that drives in a direction to contact the member, and a second that controls the force that the contact member applies to the optical member after the contact member contacts the optical member. And a drive mechanism (28b, 26B).

According to the present invention, by controlling the force applied to the optical member by the abutting member, there is no risk of damage to the optical member, and the optical member is non-rotationally symmetric and minute in a reproducible state. An amount of elastic deformation (strain) can be applied, whereby non-rotationally symmetric aberrations can be corrected.
An exposure apparatus according to the present invention includes an illumination optical system that illuminates a pattern with an exposure beam, and a projection optical system (PL) that projects an image of the pattern onto an object. At least one of the projection optical systems includes the optical system of the present invention.

  The image formation characteristic adjustment method according to the present invention is a method for adjusting the image formation characteristic of the projection optical system, and measures the rotationally asymmetric optical characteristic of the projection optical system (PL) including the optical system of the present invention. In order to correct the optical characteristics measured in one step and the first step, the abutting member abuts on the optical member by the first driving mechanism, and then the abutting member by the second driving mechanism. Has a second step of controlling the force applied to the optical member.

  In addition, although the reference numerals in parentheses attached to the predetermined elements of the present invention correspond to members in the drawings showing an embodiment of the present invention, each reference numeral of the present invention is provided for easy understanding of the present invention. The elements are merely illustrative, and the present invention is not limited to the configuration of the embodiment.

Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings. In this example, the present invention is applied when exposure is performed using a catadioptric projection optical system.
FIG. 1 is a partially cutaway view showing an exposure main body of the exposure apparatus of this example. In FIG. 1, the exposure apparatus of this example includes an exposure light source (not shown), an illumination optical system ILS, and a projection. An optical system PL, a reticle stage system, and a wafer stage system are provided, and an exposure main body including the projection optical system PL, the reticle stage system, and the wafer stage system is supported by a frame mechanism.

  The frame mechanism of this example includes a base member 1 made of a frame caster installed on the floor, three (for example, four) first columns 2 installed on the base member 1, A second column 4 is provided on one column 2 via vibration isolators 3A and 3B (actually, three or four are arranged). The vibration isolator 3A, 3B is an active vibration isolator combining a mechanical damper such as an air damper and an electromagnetic damper such as a voice coil motor. A flat support plate portion 4a is provided at the bottom of the second column 4, and a projection optical system PL, which will be described later, is mounted on a U-shaped opening at the center of the support plate portion 4a.

An exposure light source (not shown) of this example is installed in the vicinity of the frame mechanism. The exposure light source is an ArF excimer laser light source (oscillation wavelength 193 nm). In addition, a KrF excimer laser light source (wavelength 248 nm), an F ₂ laser light source (oscillation wavelength 157 nm), or a solid-state laser (YAG laser, semiconductor laser, etc.) Other harmonic generators can be used. Illumination light IL for exposure emitted from an exposure light source (not shown) is uniformly applied to a reticle R (mask) on which a transfer pattern is formed via a beam matching unit (not shown) and an illumination optical system ILS. Illuminate. The illumination optical system ILS includes a first condenser lens 11, an optical path, in addition to a beam shaping optical system (not shown), an optical integrator (a homogenizer or a homogenizer), an aperture stop of the illumination system, a relay lens system, and a field stop, respectively. A bending mirror 12 and a second condenser lens 13 are provided, and the illumination optical system ILS is housed in a sub-chamber 14 serving as an airtight chamber.

  The illumination light IL that has passed through the reticle R is subjected to a pattern of the reticle R on a wafer W (photosensitive member) coated with a resist via a projection optical system PL made of a catadioptric optical system, for example, 1/4, 1 / An image reduced at a magnification of 5 or the like is formed. The optical path of the illumination light IL in the illumination optical system ILS and the illumination light IL in the projection optical system PL is a gas having a high transmittance with respect to light in the vacuum ultraviolet region (hereinafter referred to as “transparent gas”). Some dry air, nitrogen, or a rare gas (such as helium) is supplied.

  Hereinafter, the Z-axis is taken in parallel to the optical axis AX1 of the optical system on the reticle R side of the projection optical system PL of this example, and the Y-axis is taken in parallel to the plane of FIG. 1 in a plane perpendicular to the Z-axis. A description will be given taking the X axis perpendicular to the paper surface. The projection optical system PL is placed on the support plate portion 4a by the flange portion 44a, and the inside thereof is hermetically sealed as an example. Further, the mounting surface (XY plane) of the reticle R and the mounting surface (XY plane) of the wafer W substantially coincide with the horizontal plane, and the Z axis is substantially parallel to the vertical direction. The exposure apparatus of this example is a scanning exposure type, and the scanning direction of the reticle R and the wafer W during the scanning exposure is the Y direction.

  The reticle R is held on a reticle stage 15 via a reticle holder (not shown), and the reticle stage 15 can move on the reticle base 16 at a constant speed in the Y direction, and in the X, Y, and rotational directions. The reticle base 16 is mounted on the second column 4 so that it can be displaced by a small amount. At the time of exposure, the pattern area of the reticle R is illuminated by a rectangular (slit) illumination area elongated in the X direction. The positions and rotation angles of the reticle stage 15 in the X and Y directions are measured by a laser interferometer 17, and based on the measured values and control information from a main control system (not shown) that controls the overall operation of the apparatus. A drive device (not shown) including a linear motor or the like drives the reticle stage 15. A reticle stage system is composed of the reticle stage 15, the reticle base 16, the laser interferometer 17, and its driving device.

  On the other hand, the wafer W is held on the wafer stage 32 via the wafer holder 31, and the wafer stage 32 can be moved on the wafer base 33 at a constant speed in the Y direction, and can be moved stepwise in the X and Y directions. The wafer base 33 is mounted on the base member 1 via active vibration isolation devices 38A and 38B (actually, three or four are disposed) similar to the vibration isolation devices 3A and 3B. It is placed on top. Then, on the wafer W, a pattern image of the reticle R is formed in a rectangular exposure area elongated in the X direction so as to optically correspond to the rectangular illumination area on the reticle R. The position and rotation angle of the wafer stage 32 in the X and Y directions are measured by a laser interferometer 34. Based on the measured values and control information from a main control system (not shown), a driving device including a linear motor and the like. (Not shown) drives the wafer stage 32. A wafer stage system is constituted by the wafer stage 32, the wafer base 33, the laser interferometer 34, and the driving device thereof.

  In addition, a focus / leveling mechanism for adjusting the position in the Z direction (focus position) of the wafer W and the tilt angles around the X axis and the Y axis is incorporated in the wafer stage 32. On the lower side surface of the projection optical system PL, a projection optical system 35A for projecting a plurality of slit images obliquely on the surface of the wafer W, and the reflected light from the wafer W is received to re-image the slit images. An oblique incidence type multi-point focal position detection system (autofocus sensor) is provided which includes a light receiving optical system 35B for detecting a lateral shift amount of the re-imaged image. Based on the focus position information at a plurality of (three or more) measurement points on the wafer W measured by the focus position detection system (35A, 35B), the focus / leveling mechanism continues during the exposure. The surface of W is focused on the image plane of the projection optical system PL. The projection optical system 35A and the light receiving optical system 35B are attached to a sensor column 36 attached to the bottom surface of the flange portion 44a of the projection optical system PL.

  The permeable gas is supplied to the sub-chamber 14 and the projection optical system PL from a gas supply device (not shown) via an air supply pipe (not shown) and an air supply pipe 20A, respectively. The gas in the optical system PL is collected by a gas supply device (not shown) via the exhaust pipe 21D and the exhaust pipe 21A. A part of the recovered gas may be supplied again to the airtight chamber after removing impurities. As a result, the illuminance of the illumination light IL on the wafer W is kept high, so that high throughput can be obtained.

  At the time of exposure, alignment is performed using an alignment sensor (not shown), and then an image of a part of the pattern of the reticle R is projected onto one shot area on the wafer W via the projection optical system PL, and then the reticle R is projected. And the operation of synchronously scanning the wafer W in the Y direction and the operation of moving the wafer W stepwise in the X and Y directions are repeated in a step-and-scan manner. As a result, the pattern image of the reticle R is exposed on the entire shot area of the wafer W.

Next, the configuration of the projection optical system PL of this example and the supporting method thereof will be described in detail.
In FIG. 1, a projection optical system PL composed of the catadioptric optical system of this example is a refractive first imaging optical system G1 for forming a first intermediate image of a pattern of a reticle R arranged on a first surface. And a second intermediate image that is composed of the concave mirror 22 and the two negative-power lenses L8 and L9 and is approximately the same size as the first intermediate image (the first intermediate image is an approximately equal-magnification image of the reticle pattern 2). The second image forming optical system G2 for forming the next image) and the final image of the reticle pattern (reduced image of the reticle pattern) on the wafer W disposed on the second surface using light from the second intermediate image. And a refraction-type third imaging optical system G3.

  Further, in the optical path between the first imaging optical system G1 and the second imaging optical system G2, the light from the first imaging optical system G1 is secondly combined in the vicinity of the position where the first intermediate image is formed. A reflecting surface A (first optical path bending mirror) for deflecting toward the image optical system G2 is disposed. In addition, in the optical path between the second imaging optical system G2 and the third imaging optical system G3, the light from the second imaging optical system G2 is connected in the vicinity of the formation position of the second intermediate image. A reflecting surface B (second optical path bending mirror) for deflecting toward the image optical system G3 is disposed. In the present embodiment, as the reflecting surfaces A and B, two reflecting surfaces formed on one optical path folding mirror FM are used. The first intermediate image and the second intermediate image are in the optical path between the reflecting surface A and the second imaging optical system G2, and in the optical path between the second imaging optical system G2 and the reflecting surface B, respectively. Formed.

  The first imaging optical system G1 has an optical axis AX1 parallel to the Z axis, and the optical axis of the third imaging optical system G3 coincides with an optical axis (reference optical axis) obtained by extending the optical axis AX1. Is set to In this example, the optical axis AX1 is positioned along the direction of gravity (ie, the vertical direction). As a result, the reticle R and the wafer W are arranged in parallel to each other along a plane orthogonal to the direction of gravity, that is, a horizontal plane. In addition, all the lenses constituting the first imaging optical system G1 and all the lenses constituting the third imaging optical system G3 are also arranged in parallel to the horizontal plane along the reference optical axis.

On the other hand, the optical axis AX2 of the second imaging optical system G2 is set to be orthogonal to the optical axis AX1 (reference optical axis). Further, the optical axis AX1 of the first imaging optical system G1 and the third imaging optical system at the intersection line C (strictly, the intersection line of the virtual extension surface) C of the two reflecting surfaces A and B of the optical path bending mirror FM. The optical axis of G3 is set to intersect.
In FIG. 1, the first imaging optical system G1 is configured by arranging a lens L2, a lens L3, a lens L4, a lens L5, a lens L6, and a lens L7 in this order from the reticle R side. Further, between the lens L2 and the reticle R, a plane parallel plate L1 (included in the first imaging optical system G1) that functions as a lid for the internal space of the projection optical system PL is disposed. The second imaging optical system G2 includes a negative lens L8, a negative lens L9, and a concave mirror 22 in order from the reticle side (that is, the incident side) along the light traveling path. Yes. The third imaging optical system G3 includes a lens L10, a lens L11, an aperture stop AS, a lens L12, and a lens L13 arranged in this order from the reticle side along the light traveling direction. Yes. As the projection optical system PL, in addition to the configuration shown in FIG. 1, a catadioptric system having a plurality of optical systems having optical axes intersecting each other as disclosed in, for example, Japanese Patent Laid-Open No. 2000-47114 is also available. Can be used.

In this example, synthetic quartz or fluorite (CaF ₂ crystal) is used as the optical material of all refractive optical members (lens components) constituting the projection optical system PL. The optical path bending mirror FM is formed by depositing a metal film such as aluminum or a dielectric multilayer film on two orthogonal side surfaces (reflection surfaces) of a triangular prism-shaped member. Instead of forming the first and second optical path bending mirrors (reflecting surfaces A and B) on one member, the two plane mirrors may be held so as to be orthogonal to each other. The concave mirror 22 is formed, for example, by depositing a metal film such as aluminum or a dielectric multilayer film on the reflective surface of a composite material of silicon carbide (SiC) or SiC and silicon (Si). At this time, it is preferable to coat the entire concave mirror 22 with silicon carbide or the like in order to prevent degassing. Further, as the material of the concave mirror 22, a low expansion material such as Corning's ULE (Ultra Low Expansion: trade name) or beryllium (Be) may be used. When beryllium is used, it is preferable to coat the entire concave mirror 22 with silicon carbide or the like.

  As described above, in this example, the optical axis AX1 of the first imaging optical system G1, the optical axis AX2 of the second imaging optical system G2, and the third connection are formed on the intersection line C of the reflecting surfaces A and B. The optical axis of the image optical system G3 is set so as to intersect at one point (reference point). The reflecting surface A and the reflecting surface B constitute two surfaces (with a ridge line sandwiched between them) of one optical path folding mirror FM having a triangular prism shape whose cross section is a right-angled isosceles triangle shape. As a result, the optical axes of the three imaging optical systems G1 to G3 and the ridgeline of the optical path bending mirror FM can be positioned with respect to one reference point, so that the stability of the optical system is increased, and mechanical design and optical adjustment are performed. Is easy. In addition, since the optical axis AX2 of the second imaging optical system G2 is set to be orthogonal to the common optical axis (optical axis AX1) of the first imaging optical system G1 and the third imaging optical system G3, Optical adjustment with higher accuracy can be easily performed, and the optical system has higher stability.

  Further, the plane parallel plate L1 and the lenses L2 to L7 of the first imaging optical system G1 constituting the projection optical system PL are respectively connected via the annular lens frames 42A, 42B, 42C, 42D, 42E, 42F, and 42G. It is held in cylindrical divided lens barrels 41A, 41B, 41C, 41D, 41E, 41F, 41G, and the divided lens barrels 41A to 41G are connected along the optical axis AX1 while maintaining airtightness. As shown in, for example, Japanese Patent Application Laid-Open No. 7-86152, two divided lens barrels adjacent to the divided lens barrels 41A to 41G (the same applies to the following divided lens barrels) face each other (not shown). The flanges are connected by fixing them at three or more locations with bolts. The lens frames 42A to 42G respectively hold the upper surface and the lower surface of the outer peripheral portion of the plane parallel plate L1 and the flange portions of the outer peripheral portions of the lenses L2 to L7 at a plurality of locations (three or more locations). Hold the object. In this case, the lens frame 42A and the plane-parallel plate L1 are closed in a state where the upper end portion of the divided lens barrel 41A is kept airtight, but the above permeable gas is circulated through the other lens frames 42B to 42G. A plurality of openings are formed. An air supply pipe 20A for supplying a permeable gas is connected to the upper divided barrel 41B.

  Similarly, the lenses L10 to L13 of the third imaging optical system G3 are held in the cylindrical divided lens barrels 41H, 44, 41I, and 41J through the annular lens frames 42H, 42K, 42I, and 42J, respectively. ing. The aperture stop AS is held in a divided lens barrel 41K sandwiched between the divided lens tubes 44 and 41I, and the divided lens tubes 41H, 44, 41K, 41I, and 41J are connected in a state of maintaining airtightness. . The split lens barrel 44 that holds the lens L11 is provided with a flange portion 44a, and the projection optical system PL is placed on the support plate portion 4a by the flange portion 44a. In this case, the lens frame 42J and the lens L13 are closed in a state where the lower end portion of the split lens barrel 41J is kept airtight, but the other lens frames 42H, 42K, and 42I are used for circulating a permeable gas. A plurality of openings are formed. An exhaust pipe 21A for exhausting the gas inside the projection optical system PL is connected to the lowermost divided lens barrel 41J.

Further, a cylindrical divided lens barrel 43 having an opening in the + Y direction is connected between the two divided lens barrels 41G and 41H, and an optical path bending mirror is connected to a protrusion in the divided lens barrel 43 via a holding frame 43a. FM is fixed. In this example, the first partial lens barrel 7 is composed of 13 divided lens barrels 41A to 41K, 43, and 44.
The lenses L8 and L9 of the second imaging optical system G2 are held in the cylindrical divided lens barrels 45 and 41L via holding frames 46A and 46B, respectively, and the concave mirror 22 has a holding member 48 on the back side. Held by. On the back surface of the concave mirror 22, three protrusions provided at equal intervals around the optical axis of the concave mirror 22 are formed. The split lens barrel 47 has three clamp mechanisms (not shown) that sandwich the protrusions. The clamp mechanism includes a flexure member that absorbs stress (for example, thermal deformation of the concave mirror 22 due to absorption of exposure light) generated between the concave mirror 22 and the split lens barrel 47. With this clamping mechanism, the optical performance of the concave mirror 22 can be maintained satisfactorily. The divided lens barrels 45, 41L, 47 are connected along the optical axis AX2 while maintaining airtightness. In this case, the distal end portion in the −Y direction of the divided lens barrel 45 is connected so as to seal the opening provided in the divided lens barrel 43 of the first partial lens barrel 7. Further, the back surface of the holding member 48 that holds the concave mirror 22 is sealed with a film-like cover (not shown), and the holding frames 46A and 46B are formed with a plurality of openings for allowing the permeable gas to flow. The transmissive gas is supplied with the optical path of the second imaging optical system G2 being substantially sealed. A third partial lens barrel 8 is constituted by the three divided lens barrels 45, 41L, 47, and this partial lens barrel 8 is connected to the first partial lens barrel 7 so as to be orthogonal to the + Y direction. Yes.

  Next, a correction mechanism for correcting non-rotationally symmetric aberrations such as center ass as the imaging characteristics of the projection optical system PL of this example will be described. The correction mechanism of this example is a small amount of distortion (for example, about ± 100 nm) in the optical axis direction independently at a plurality of positions (for example, 9 positions) of the peripheral portion of the concave mirror 22 that is an optical member in the projection optical system PL. It is a mechanism that gives non-rotationally symmetric local deformation. The distortion applied to the concave mirror 22 by the correction mechanism of this example is a distortion that is almost proportional to the applied force within the range of elastic deformation, and is a reproducible deformation. Further, although the optical axis AX1 (parallel to the Z axis) of the projection optical system PL of this example is parallel to the vertical line, the concave mirror 22 to which the distortion is applied is set horizontally, and the optical axis of the concave mirror 22 is substantially horizontal. Parallel. In this way, a desired distortion can be easily applied to the horizontally placed concave mirror 22 by applying a slight force.

  As shown in FIG. 1, a convex portion 22 a having a predetermined width is provided on the entire circumference of the side surface of the rotationally symmetric concave mirror 22. In addition, the side surface of the concave mirror 22 on the reflection surface side with respect to the convex portion 22 a is accommodated in the front portion 47 a of the split lens barrel 47, and the holding member 48 is accommodated in the rear portion 47 b of the split lens barrel 47. The flange portion (not shown) of the front end portion of the split lens barrel 47 is connected to the flange portion (not shown) of the rear end portion of the split lens barrel 41L.

  FIG. 2 is a perspective view showing the split lens barrel 47 that holds the concave mirror 22 in FIG. 1. In FIG. 2, the same configuration for applying distortion to the side surfaces of the concave mirror 22 at nine positions on the back surface of the concave mirror 22 is shown. The minute amount deformation mechanisms 49A, 49B, 49C, 49D, 49E, 49F, 49G, 49H, and 49I are fixed. As shown in FIG. 1, the minute amount deformation mechanisms 49 </ b> A to 49 </ b> I are fixed to a mounting surface 48 c provided on the outer peripheral portion of the flat plate portion 48 a of the holding member 48 by a plurality of bolts (not shown).

  In the example of FIG. 2, three sets of minute amount deformation mechanisms 49A to 49C, 49D to 49F, and 49G to 49I, each of which is arranged at a small angular interval, are arranged at equal angular intervals. In addition, nine minute amount deformation mechanisms 49 </ b> A to 49 </ b> I may be arranged at equiangular intervals around the optical axis of the concave mirror 22. Further, the number of minute amount deformation mechanisms 49A to 49I may be any number as long as it is plural. However, if the number of minute deformation mechanisms 49A to 49I is about nine or more, a substantially non-rotationally symmetric distortion can be imparted to the concave mirror 22, so that non-rotationally symmetric aberration can be corrected with high accuracy.

  FIG. 3 is a diagram in which a part of one minute deformation mechanism 49A in FIG. 2 is representatively cut away. In FIG. 3, a notch 47c provided on the rear inner surface of the split lens barrel 47 in FIG. A support portion 48b of the holding member 48 is fixed inside by a bolt (not shown), and a minute amount deformation mechanism 49A is fixed to a mounting surface 48c of the holding member 48 by a bolt (not shown). The minute amount deformation mechanism 49A includes a substantially U-shaped frame 23 in which two support portions 23a and 23b are connected, and a coarse motion direct acting micrometer (hereinafter referred to as a coarse motion micrometer) fixed to the support portion 23a. 26A, a direct acting micrometer for fine movement (hereinafter referred to as a fine movement micrometer) 26B fixed to the convex portion 23c on the inner surface of the support portion 23b, and three plates inside the frame 23. A movable plate 24 supported so as to be movable in the optical axis direction (Y direction) of the concave mirror 22 via springs 25A, 25B, 25C, a load sensor 27 fixed to the movable plate 24 with a bolt 50, a micrometer 26A, and 26B is fixed to the load sensor 27 with a bolt 53 in order to connect the respective spindle portions 26Aa and 26Ba to the load sensor 27 (or the movable plate 24). The and a coupling member 28.

  The load sensor 27 of this example includes a probe 27a extending parallel to the optical axis of the concave mirror 22, and a strain gauge type sensor unit 27b for detecting a force (load) applied to the probe 27a in the ± Y direction. Load cell. That is, the load sensor 27 is a tension compression type capable of detecting a force in the ± Y direction. Then, by processing the signal detected by the sensor unit 27b by the signal processing system 55, the force applied to the probe 27a in the ± Y direction is, for example, a stroke of about ± 150 g weight and a resolution of about 1 g weight or less. Is detected. The force detected by the load sensor 27 is a reaction force from the convex portion 22a of the concave mirror 22 with which the probe 27a abuts (contacts).

  Furthermore, a substantially U-shaped tip member 29 is connected to the tip portion of the probe 27a so as to sandwich the convex portion 22a of the concave mirror 22 in the Y direction. Hemispherical contact portions 54A and 54B are fixed to the ± Y-direction portions of the tip member 29 facing the convex portions 22a. In FIG. 3 (the same applies to FIGS. 5 and 6 below), the distance (gap) g between the contact portions 54A and 54B is expressed to be considerably large with respect to the thickness t of the convex portion 22a for easy understanding. However, in practice, as an example, the gap g is only about 0.1 to 0.3 mm larger than the thickness t. In this configuration, when the probe 27a is displaced in the −Y direction or the + Y direction, the contact portion 54A or 54B contacts the convex portion 22a, respectively. In this example, a strain in the ± Y direction is applied to the convex portion 22a by a force in the ± Y direction applied from the probe 27a and the tip member 29 to the convex portion 22a, and the reaction force from the convex portion 22a at that time is applied to the load sensor 27. The signal processing system 55 obtains the deformation amount of the convex portion 22a by multiplying the reaction force by a coefficient obtained in advance.

  The deformation amount (or the reaction force itself) thus obtained is displayed on, for example, a display unit (not shown) provided in the signal processing system 55, and is not shown as detection data if necessary. Supplied to a computer for data processing. As an example, the thickness t of the protrusion 22a is set so as to be deformed by about 1 nm in the Y direction when the force from the probe 27a is 1 g. In this case, if the stroke of the force from the probe 27a is about ± 100 g weight, a distortion of about ± 100 nm can be given to the convex portion 22a.

  The connecting member 28 includes a plate spring portion 28a having a high rigidity and a plate spring portion 28b having a low rigidity. The open end of the former plate spring portion 28a is a spindle of the coarse movement micrometer 26A by a bolt 51 and a nut 52. The open end of the latter leaf spring portion 28b is fixed to the tip of the spindle portion 26Ba of the fine movement micrometer 26B. As an example, as shown in FIG. 4, the leaf spring portion 28 a is formed of a substantially square flat plate spring, and the leaf spring portion 28 b has a substantially rectangular area that is about a fraction of the area of the leaf spring portion 28 a. It consists of a flat plate spring. As a result, even if the drive amounts of the micrometers 26A and 26B are the same, the displacement of the movable plate 24 and the probe 27a in the Y direction in conjunction with the drive amount of the spindle portion 26Aa of the coarse movement micrometer 26A in the Y direction is reduced. The displacement is greater than the displacement associated with the drive amount of the spindle portion 26Ba of the fine movement micrometer 26B in the Y direction.

  That is, a coarse movement mechanism that roughly displaces the probe 27a in, for example, the Y direction is configured from the coarse movement micrometer 26A and the leaf spring portion 28a, and the probe 27a is narrow in the Y direction from the fine movement micrometer 26B and the leaf spring portion 28b. A fine movement mechanism that displaces with high accuracy within the stroke is configured. In this case, if the contact portion 54A (or 54B) is in contact with the convex portion 22a, the force applied to the convex portion 22a from the probe 27a by 10 g by operating the coarse movement micrometer 26A or the fine movement micrometer 26B. Alternatively, it can be controlled in units of about 1 g weight. In this example, as an example, until the contact portion 54A (or 54B) of the tip member 29 contacts the convex portion 22a, the probe 27a is driven toward the convex portion 22a using the coarse movement mechanism, and the contact portion After 54A (or 54B) comes into contact with the convex portion 22a, the force applied from the probe 27a to the convex portion 22a is controlled using the fine movement mechanism. As a result, the force or distortion applied to the convex portion 22a can be controlled with high accuracy.

In this case, as shown in FIG. 2, in the minute amount deformation mechanisms 49A to 49I, the coarse movement mechanism including the coarse movement micrometer 26A and the fine movement mechanism including the fine movement micrometer 26B are along the radial direction from the center of the concave mirror 22. Are arranged.
Further, the micrometers 26A and 26B of this example are manually operated. However, the micrometers 26A and 26B are electric types, and the deformation amount detected based on the deformation amount of the convex portion 22a (or the reaction force from the convex portion 22a) detected by the load sensor 27 and the signal processing system 55. You may control operation | movement of micrometer 26A and 26B by a closed loop system so that (reaction force) may become a predetermined target value.

  Further, in FIG. 3, two leaf springs 25A and 25B among the three leaf springs 25A to 25C are triple-folded and highly flexible, and the movable plate 24 and the support portion 23b The other leaf springs 25C connect the upper end portion of the movable plate 24 in the + Y direction and the support portion 23a. The support 23b is formed with a notch 23d for avoiding mechanical interference with the leaf spring 25A. By the link mechanism, the movable plate 24 and the probe 27a move in parallel to the support portion 23b, that is, in parallel to the Y axis. As shown in FIG. 4, openings 25Aa and 25Ba are formed in the leaf springs 25A and 25B, respectively, through which the fine movement micrometer 26b is passed. Further, the split lens barrel 47 is formed with an opening 47d for passing the tip member 29, and the holding member 48 is formed with a notch 48f for passing the spindle portions 26Aa and 26Ba of the micrometers 26A and 26B. ing.

Next, an example of an assembly method of the minute amount deformation mechanism 49A of FIG. 3 will be described with reference to an exploded perspective view of FIG.
In FIG. 4, after the movable plate 24 is connected to the frame 23 via plate springs 25 </ b> A to 25 </ b> C, the coarse movement micrometer 26 </ b> A and the fine movement micrometer 26 </ b> B are attached to the support portions 23 a and 23 b of the frame 23, respectively. The sensor portion 27b of the load sensor 27 is provided with four long hole portions 27c and two long hole portions 27d (one is not shown) for the bolts 50 and 53. The connecting member 28 is provided with arm portions 28c and 28d having the same width as the sensor portion 27b so as to be orthogonal to the leaf spring portions 28a and 28b, and the leaf spring portions 28a and 28b are respectively bolts. Openings 28f and 28g for 51 are provided, and an opening 28e for passing the probe 27a is provided at an intermediate position between them. In addition, screw holes that are screwed into the bolts 53 are provided at the distal ends of the arm portions 28c and 28d.

  Therefore, with the probe 27a passed through the opening 28e of the connecting member 28, the arm portions 28c and 28d are attached to the side surface of the sensor portion 27b, and the arm portions 28c and 28d (bolts for the arm portion 28d are used with the bolts 53). (Not shown) is fixed to the sensor portion 27b. And the connection part 29a of the front-end | tip member 29 is fixed to the front-end | tip part of the probe 27a. Next, the sensor portion 27 b (the load sensor 27 and the connecting member 28 are integrated at this stage) is fixed to the movable plate 24 via the four bolts 50. Thereafter, with the bolt 51 passed through the nut 52 being passed through the openings 28f and 28g of the leaf spring portions 28a and 28b, the bolt 51 is tightened into the screw holes of the spindle portions 26Aa and 26Ba, thereby causing the leaf spring portions 28a and 28b. To the micrometers 26A and 26B. This completes the assembly of the minute amount deformation mechanism 49A of FIG.

Next, an example of how to use the minute amount deformation mechanism 49A of FIG. 3 will be described with reference to FIGS. In this case, in the main control system (not shown) in advance, the convex portion 22a of the concave mirror 22 necessary for correcting the predetermined non-rotationally symmetric aberration of the projection optical system PL in FIG. It is assumed that a target value of the deformation amount (distortion amount) is obtained.
First, in FIG. 3, when the target value of the deformation amount is a value in the direction of the reflecting surface MP (−Y direction) (the sign at this time is +), the operator, for example, loads the load sensor 27. While detecting the deformation amount of the convex portion 22a (or the reaction force from the convex portion 22a) via the signal processing system 55, the coarse motion micrometer 26A is operated to drive the probe 27a in the -Y direction. Then, when the detected deformation amount exceeds the predetermined minimum detection amount, the operation of the coarse movement micrometer 26A is stopped. In this state, as shown in FIG. 5, the + Y direction side contact portion 54A of the tip member 29 is in contact with the convex portion 22a. Thereafter, the operator operates the fine movement micrometer 26B to drive the probe 27a in the −Y direction until the detected deformation amount of the convex portion 22a reaches the target value.

  On the other hand, in FIG. 3, when the target value of the deformation amount is a value in the back surface direction (+ Y direction) of the concave mirror 22, the operator deforms the convex portion 22 a via the load sensor 27 and the signal processing system 55. While detecting the amount, the coarse movement micrometer 26A is operated to drive the probe 27a in the + Y direction. When the absolute value of the detected deformation amount exceeds a predetermined minimum detection amount, the operation of the coarse movement micrometer 26A is stopped. In this state, as shown in FIG. 6, the contact portion 54 </ b> B on the −Y direction side of the tip member 29 is in contact with the convex portion 22 a. Thereafter, the operator operates the fine movement micrometer 26B to drive the probe 27a in the + Y direction until the detected deformation amount of the convex portion 22a reaches the target value. By this operation, a desired deformation amount (distortion amount) in the ± Y direction can be given to the convex portion 22a with high accuracy and reproducibility.

  Next, an example of an operation for correcting the center ass using the aberration correction mechanism of FIG. 2 will be described. As a premise, in FIG. 1, in order to measure the center ass of the projection optical system PL, as shown in the enlarged view of FIG. 8A, line-and-arrays arranged at a predetermined pitch in the X direction and the Y direction are used. A test reticle on which space patterns (hereinafter referred to as “L / S patterns”) 60X and 60Y are formed is loaded on the reticle stage 15 instead of the reticle R in FIG. Then, an unexposed wafer W coated with a resist is loaded on the wafer stage 32. Next, the centers of the L / S patterns 60X and 60Y in FIG. 8A are moved to the exposure center of the projection optical system PL in FIG. 1, and the position of the wafer W in the Z direction is gradually changed by the wafer stage WST. The images of the L / S patterns 60X and 60Y are exposed to a series of shot areas on the wafer W via the projection optical system PL while performing step movement in the X direction and the Y direction. Next, the wafer W is developed, and the focus position F1 of the wafer W when the image of the L / S pattern 60X is transferred with the highest resolution and the image of the L / S pattern 60Y are transferred with the highest resolution. When the focus position F2 of the wafer W at this time is obtained, the difference (= F1-F2) becomes the center ass.

  When the center area exceeds a predetermined allowable range, the wavefront 61 in FIG. 8B is shown on the optical member (for example, the concave mirror 22) in the vicinity of the pupil plane PLP of the projection optical system PL in FIG. In addition, a wavefront that is originally concentric (for example, a wavefront of light emitted from one point on the object plane) is, for example, an ellipse that is elongated in the X direction. Note that the Y direction in FIG. 8B corresponds to the Z direction in FIG. Therefore, in order to return the wavefront to a substantially concentric shape, the concave mirror 22 is deformed in this example.

  FIG. 7 shows the concave mirror 22, and the concave mirror 22 maintains a rotationally symmetric shape in a state where aberration correction is not performed. On the other hand, in order to correct the aberration as shown in FIG. 8B, as an example, in FIG. 7, the convex portion 22a is deformed in the −Y direction by three minute amount deformation mechanisms 49A, 49E, and 49I. Thus, the concave mirror 22 is slightly deformed in a non-rotational symmetry. As a result, a non-rotationally symmetric aberration such as the center as shown in FIG. 8B can be corrected.

  Further, for example, in the state where the displacement in the Y direction of the convex portion 22a of the concave mirror 22 by the minute amount deformation mechanisms 49A to 49I is changed in various ways, for example, aberration such as center astigmatism using the measurement pattern of FIG. By measuring the amount of occurrence, the amount of deformation required in the Z direction of the convex portion 22a by the minute amount deformation mechanisms 49A to 49I can be obtained from the amount of occurrence of aberration during actual aberration correction. Therefore, the non-rotationally symmetric aberration of the projection optical system PL can be quickly corrected by the minute amount deformation mechanisms 49A to 49I. By correcting the non-rotationally symmetric aberration of the projection optical system PL in this way, the reticle pattern can be transferred onto the wafer with high accuracy in the subsequent exposure process.

  Further, the non-rotationally symmetric aberration of the projection optical system PL occurs even under illumination conditions in which the illumination area of the reticle R is non-rotationally symmetric or the light quantity distribution on the pupil plane such as dipole illumination is non-rotationally symmetric. There are things to do. In such a case, the non-rotationally symmetric aberration generated during exposure can be corrected by driving the minute amount deformation mechanisms 49A to 49I (micrometers 26A and 26B) with a drive motor.

Next, it is as follows when the structure of said embodiment and a part of its effect | action are put together.
1) In the concave mirror 22 in the projection optical system PL of FIG. 1, as shown in FIG. 3, a probe 27a arranged so as to be able to come into contact with the concave mirror 22 and a direction in which the probe 27a is brought into contact with the concave mirror 22 The coarse movement mechanism including the coarse movement micrometer 26A that is driven to the right and the abutment portion 54A or 54B at the tip of the probe 27a abuts on the convex portion 22a of the concave mirror 22, and then the force applied by the probe 27a to the convex portion 22a is controlled. And a fine movement mechanism including a fine movement micrometer 26B. Therefore, the force applied to the convex portion 22a can be controlled with high accuracy, and the convex portion 22a is only elastically deformed. The deformation is reproducible, and the risk of damaging the convex portion 22a and the concave mirror 22 is substantially reduced. Absent. Accordingly, it is possible to correct non-rotationally symmetric aberration in a reproducible state.

2) The probe 27a is provided with a sensor unit 27b for measuring the reaction force from the concave mirror 22. Therefore, by controlling the force while monitoring the force applied to the convex portion 22a, the deformation amount of the convex portion 22a can be controlled with high accuracy.
Without providing the sensor portion 27b, for example, the reaction force from the convex portion 22a and the deformation amount of the convex portion 22a can be roughly calculated from the driving amounts of the coarse movement micrometers 26A and 26B.

3) Since the sensor unit 27b is a strain gauge type sensor, the load sensor 27 can be compactly assembled, and a large number of minute amount deformation mechanisms 49A and the like can be easily arranged around the concave mirror 22.
As a detection method of the load sensor 27, in addition to the strain gauge method, a method of detecting strain of the silicon substrate, a method using a piezoelectric element, or the like can be used.

4) The portion of the concave mirror 22 where the probe 27a comes into contact is in the convex portion 22a at the peripheral portion of the concave mirror 22, and the tip portion of the probe 27a has contact portions 54A and 54B arranged so as to sandwich the convex portion 22a. The provided tip member 29 is fixed. Accordingly, a force in the ± Y direction can be applied to the convex portion 22a, and aberration correction can be performed with high accuracy.
The tip member 29 may be omitted, and the tip of the probe 27a may be brought into direct contact with the rear surface of the convex portion 22a or the peripheral edge of the concave mirror. In this case, as the load sensor 27, a compression type that can detect only the reaction force in the + Y direction can be used.

  5) The coarse movement mechanism of the above embodiment has a coarse movement micrometer 26A that displaces the other end of the leaf spring portion 28a, one end of which is fixed to the probe 27a (load sensor 27), and the fine movement mechanism is the probe 27a. (Load sensor 27) has a fine movement micrometer 26B that is fixed at one end and displaces the other end of the leaf spring portion 28b, which is less rigid than the leaf spring portion 28a, via the leaf spring portions 28a and 28b. Thus, the probe 27a can be easily driven.

In place of the micrometers 26A and 26B, other displacement mechanisms such as a cam mechanism and a rack and pinion mechanism can be used. Further, in order to make the rigidity of the leaf springs 28a and 28b different, the thickness may be changed together with the size or the same size.
6) In FIG. 3, since the probe 27a (load sensor 27) is connected to the support portion 23b by a link mechanism made up of leaf springs 25A and 25B, the probe 27a is connected to the support portion 23b and eventually to the optical axis of the concave mirror 22. It can be moved in parallel. Therefore, a force parallel to the optical axis can always be applied to the convex portion 22a of the concave mirror 22 in a reproducible state.

  7) The concave mirror 22 in FIG. 1 is rotationally symmetric. As shown in FIG. 2, in the minute amount deformation mechanisms 49A to 49I, a coarse movement mechanism including a coarse movement micrometer 26A and a fine movement mechanism including a fine movement micrometer 26B. Are arranged along the radial direction from the center of the concave mirror 22. With this arrangement, a large number of minute amount deformation mechanisms 49 </ b> A to 49 </ b> I can be arranged compactly with respect to the concave mirror 22. In this configuration, it goes without saying that the coarse movement micrometer 26A may be arranged on the inner side and the fine movement micrometer 26B may be arranged on the outer side.

However, the shape of the optical member to be corrected may be non-rotationally symmetric.
8) Various non-rotationally symmetric aberrations can be corrected by disposing the minute amount deformation mechanisms 49A to 49I at a plurality of positions on the peripheral portion of the concave mirror 22.
9) In the exposure apparatus of FIG. 1, forces from the minute amount deformation mechanisms 49A to 49I are applied to the concave mirror 22 in the projection optical system PL. Therefore, the non-rotationally symmetric aberration of the projection optical system PL can be corrected.

  For example, the displacement distribution of at least one peripheral edge of a plurality of lenses (or the concave mirror 22 may be included together) near the pupil plane of the projection optical system PL is independently controlled by the correction mechanism of the above embodiment. By doing so, it is possible to correct the non-rotationally symmetric aberration with higher accuracy. It is also possible to control the displacement distribution of the peripheral portion of the optical member in the vicinity of the object plane or the image plane of the projection optical system PL, thereby correcting various non-rotationally symmetric aberrations. is there.

The present invention is also applicable to controlling the displacement distribution of a lens or mirror in an illumination optical system (or illumination optical system and projection optical system).
10) The projection optical system PL of FIG. 1 includes a first partial barrel 7 having an optical axis substantially parallel to the vertical direction, and a second partial barrel 8 having an optical axis intersecting the partial barrel 7. The optical member having the above and to which a force is applied by the correction mechanism is a concave mirror 22 disposed in the second partial barrel 8. That is, since the concave mirror 22 is placed horizontally, a desired slight deformation can be applied with a small force applied from the minute amount deformation mechanisms 49A to 49I.

Note that the optical member to be deformed may be placed vertically (the optical axis is in the vertical direction).
11) The imaging characteristic adjusting method of the above embodiment includes a step of measuring the rotationally asymmetric imaging characteristic of the projection optical system PL, and a coarse motion mechanism for correcting the imaging characteristic measured in that step. After the probe 27a (tip member 29) comes into contact with the concave mirror 22, the step of controlling the force applied to the concave mirror 22 by the probe 27a (tip member 29) by the fine movement mechanism is included. Therefore, the imaging characteristics can be corrected with high accuracy.

  In the exposure apparatus of the above-described embodiment, an illumination optical system and a projection optical system composed of a plurality of lenses and mirrors are incorporated into the exposure apparatus main body and optical adjustment is performed, so that a reticle stage or wafer stage composed of a large number of mechanical parts Can be manufactured by attaching a wire to a main body of the exposure apparatus, connecting wiring and piping, and performing general adjustment (electrical adjustment, operation check, etc.). The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Further, when a semiconductor device is manufactured using the exposure apparatus of the above-described embodiment, the semiconductor device includes a step of designing a function and performance of the device, a step of manufacturing a reticle based on this step, and a wafer from a silicon material. Forming, aligning with the projection exposure apparatus of the above embodiment to expose the pattern of the reticle onto the wafer, forming a circuit pattern such as etching, device assembly step (dicing process, bonding process, packaging process) Including) and an inspection step.

  In the present invention, when correcting the aberration of the projection optical system of a batch exposure type exposure apparatus such as a stepper or an immersion type exposure apparatus disclosed in, for example, International Publication (WO) No. 99/49504. Can also be applied. The present invention can also be applied to the case where aberration correction of a projection optical system of an exposure apparatus that uses extreme ultraviolet light (EUV light) having a wavelength of about several nm to 100 nm as an exposure beam is performed.

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

  When the present invention is applied to an exposure apparatus, non-rotationally symmetric aberrations can be corrected quickly, various patterns can be transferred onto the substrate with high accuracy, and devices with fine patterns can be highly accurate. Can be manufactured.

It is the figure which notched a part which shows the main-body part of the exposure apparatus of an example of embodiment of this invention. It is a perspective view which shows the micro deformation | transformation mechanism 49A-49I with which the concave mirror 22 in FIG. 1 was mounted | worn. It is the figure which notched the part which shows the minute amount deformation | transformation mechanism 49A in FIG. FIG. 4 is an exploded perspective view showing a minute amount deformation mechanism 49A of FIG. 3. In FIG. 3, it is a figure of the principal part which shows the state which contacted the contact part 54A of + Y direction to the concave mirror 22. FIG. In FIG. 3, it is a figure of the principal part which shows the state which contact | abutted the contact part 54B of -Y direction to the concave mirror 22. FIG. It is a perspective view which shows an example of the deformation | transformation state of the concave mirror 22 at the time of performing non-rotationally symmetric aberration correction. (A) is an enlarged plan view showing an example of a pattern for center ass measurement, and (B) is a diagram showing an example of wavefront aberration on the pupil plane of the projection optical system.

Explanation of symbols

R ... reticle, W ... wafer, ILS ... illumination optical system, PL ... projection optical system, 7 ... first partial barrel, 8 ... second partial barrel, 22 ... concave mirror, 23 ... frame, 24 ... movable plate 25A, 25B ... leaf spring, 26A, 26B ... micrometer, 27 ... load sensor, 27a ... probe, 28 ... coupling member, 28a, 28b ... leaf spring part, 29 ... tip member, 47 ... split lens barrel, 48 ... Holding member, 49A to 49I ... minute amount deformation mechanism, 54A, 54B ... contact portion

Claims (11)

In an optical system having an optical member,
A contact member disposed away from the optical member and capable of contacting the optical member;
A first drive mechanism for driving the contact member in a direction to contact the optical member;
An optical system comprising: a second drive mechanism that controls a force that the contact member applies to the optical member after the contact member contacts the optical member.   The optical system according to claim 1, further comprising a sensor that measures a reaction force from the optical member to the contact member.   The optical system according to claim 2, wherein the sensor is a sensor using a strain gauge. The part of the optical member with which the contact member abuts is at the periphery of the optical member,
The contact member includes a first contact portion disposed on one side with the peripheral edge portion interposed therebetween, and a second contact portion disposed on the other side with the peripheral edge portion interposed therebetween,
The first drive mechanism relatively moves the first contact portion and the second contact portion to contact the first contact portion on one side of the peripheral portion, and Abutting the second abutting portion on the other side;
The second drive mechanism further includes the first contact portion and the second contact portion after the first contact portion and the second contact portion contact the peripheral portion by the first drive mechanism. 4. The optical system according to claim 1, wherein a force applied to the optical member is controlled by relatively moving the portion. The first drive mechanism includes a first leaf spring having one end connected to the contact member, and a first displacement mechanism that displaces the other end of the first leaf spring,
The second drive mechanism includes a second plate spring having one end connected to the contact member and having a lower rigidity than the first plate spring, and a second plate spring that displaces the other end of the second plate spring. The optical system according to claim 1, further comprising a displacement mechanism.   6. The optical system according to claim 1, further comprising a link mechanism that moves the abutting member in parallel with the optical axis of the optical member.   The shape of the optical member is rotationally symmetric, and the first and second drive mechanisms are arranged along the radial direction from the center of the optical member. The optical system described. The shape of the optical member is rotationally symmetric,
8. The deformation mechanism of the optical member including the abutting member and the first and second driving mechanisms is disposed at a plurality of locations on the peripheral edge of the optical member. The optical system according to one item. In an exposure apparatus having an illumination optical system that illuminates a pattern with an exposure beam, and a projection optical system that projects an image of the pattern onto an object,
An exposure apparatus, wherein at least one of the illumination optical system and the projection optical system includes the optical system according to any one of claims 1 to 8. The projection optical system has a first partial lens barrel having an optical axis substantially parallel to the vertical direction, and a second partial lens barrel having an optical axis intersecting the first partial lens barrel,
The exposure apparatus according to claim 9, wherein the optical member of the optical system is a concave mirror disposed in the second partial barrel. A method for adjusting the imaging characteristics of a projection optical system,
A first step of measuring rotationally asymmetric optical properties of a projection optical system including the optical system according to any one of claims 1 to 8;
In order to correct the optical characteristics measured in the first step, the contact member is brought into contact with the optical member by the first drive mechanism, and then the contact member is moved into the optical member by the second drive mechanism. And a second step of controlling a force applied to the image forming method.

Images