JP2005037896A - Projection optical system, exposure apparatus and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catadioptric projection optical system that can easily secure a space near a reticle, simplifies mechanical structure and minimize the influence of a coating on a plane mirror. <P>SOLUTION: The catadioptric projection optical system has a 1st imaging optical system having at least one lens and forming a 1st intermediate image of a 1st object, a 2nd imaging optical system having at least one lens and at least one concave mirror and forming a 2nd intermediate image of the 1st object, and a 3rd imaging optical system having at least one lens and forming the image of the 1st object on the 2nd object in order from the 1st object side, and forms the image of the 1st object on a 2nd object. Assuming that the system has at least one deflection reflecting member, and the paraxial magnification of the 1st imaging optical system is β1 and the paraxial magnification of the 2nd imaging optical system is β2, 0.70<¾β1 β2¾<3 is met. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection optical system, a projection exposure apparatus using the projection optical system, and a device manufacturing method, and more particularly to a catadioptric projection optical system using a reflecting mirror in a projection optical system that projects and exposes a reticle pattern onto a wafer. .

  In a photolithography process for manufacturing a semiconductor integrated circuit, a projection exposure apparatus that projects and exposes a pattern drawn on a mask or a reticle onto a wafer coated with a photoresist or the like via a projection optical system is used. ing. In recent years, with the progress of higher integration of integrated circuits, the required specifications and required performance for projection exposure optical systems have become increasingly severe.

  In order to obtain high resolution in the projection exposure optical system, it is necessary to shorten the exposure wavelength or increase the NA. When the exposure wavelength is shortened to obtain a high resolution and the exposure wavelength reaches a wavelength region such as 193 nm (ArF) or 157 nm (F2), it is high when a transmission optical element other than a quartz lens or a fluorite lens is used. Since the transmittance cannot be obtained, the lens materials that can be used to obtain a predetermined light amount are limited to quartz and fluorite. As an optical system of a projection exposure apparatus that uses light in a wavelength region such as 193 nm and 157 nm, for example, all disclosed in JP-A-10-79345 and the like are composed of refractive lenses, and the number of lenses is large and the total glass thickness is large. When a large optical system is used, the amount of light absorbed in the optical system increases, so that the exposure amount on the wafer decreases, which causes a decrease in throughput. In addition, problems (thermal aberration) such as focal position fluctuation and aberration fluctuation due to heat absorption of the lens (the lens temperature rises by absorbing light) occur. Further, although a quartz lens and a fluorite lens can be used at an exposure wavelength of 193 nm, it is difficult to correct chromatic aberration because the difference in dispersion value between them is not so large. A plurality of achromatic lenses having an erasing surface are required. When there are a plurality of such achromatic lenses in the optical system, the total glass material thickness of the optical system is increased, and the above-described problems such as a decrease in transmittance and generation of thermal aberration become more remarkable. As for fluorite, it is difficult to manufacture a fluorite having characteristics that can withstand the design performance of the projection optical system, and it is difficult to manufacture a fluorite having a large diameter. This makes color correction more difficult and increases costs. Furthermore, when the exposure wavelength is 157 nm, the only lens material that can be used is fluorite, and it is difficult to correct chromatic aberration with only a single material. As described above, since it becomes difficult to construct a projection optical system only with a refractive system, by using a mirror in the optical system, an attempt is made to solve the above-mentioned problems such as a decrease in transmittance and correction of chromatic aberration. Various proposals have been made.

For example, a reflection projection optical system composed only of a reflection system is disclosed in Japanese Patent Application Laid-Open Nos. 9-2111332 and 10-90602. Further, a catadioptric projection optical system combining a reflective system and a refractive system is disclosed in US Pat. No. 5,650,877, Japanese Patent Laid-Open No. 62-210415, Japanese Patent Laid-Open No. 62-258414, and Japanese Patent Laid-Open No. Hei 2- No. 66510, JP-A-3-282527, JP-A-5-188298, JP-A-6-230287, JP-A-10-3039, JP-A-2001-47114, JP-A-8-62502 This is disclosed in Japanese Patent Laid-Open No. 2002-83766.
JP-A-10-079345 JP 09-211132 A Japanese Patent Laid-Open No. 10-090602 US Pat. No. 5,650,877 JP-A-62-210415 Japanese Patent Laid-Open No. 62-258414 Japanese Patent Laid-Open No. 02-066651 Japanese Patent Laid-Open No. 03-282527 JP 05-188298 A Japanese Patent Laid-Open No. 06-230287 JP-A-10-003039 JP 2001-047114 A JP 08-065022 A JP 2002-083766 A

  When constructing a projection optical system including a reflection system corresponding to such shortening of the exposure wavelength and high NA, it is natural that correction of chromatic aberration is possible, and it is ideally sufficient on the image plane. It is desirable to have a simple configuration in which a large imaging region can be obtained and a sufficient image-side working distance can be secured. If a sufficiently large imaging region width is obtained on the image plane, the scanning projection exposure apparatus is advantageous in terms of throughput, and exposure fluctuations can be suppressed. If a sufficient working distance on the image side can be secured, it is preferable for configuring an autofocus system of the apparatus, a transfer system of the wafer stage, and the like. With a simple configuration, the mechanical barrel and the like are not complicated, and there are advantages in assembly and manufacturing.

  Examining the conventional example from the above viewpoint, first, in US Pat. No. 5,650,877, a mangin mirror and a refractive member are arranged in an optical system, and an image of a reticle is exposed on a wafer. However, this optical system has the disadvantages that the central part of the pupil is shielded (broken out) at all angles of view and the exposure area cannot be made large. Further, if the exposure area is increased, the light shielding at the center of the pupil increases, which is not preferable. Further, the refractive surface of the Mangin mirror forms a beam splitting surface, and the amount of light is halved each time it passes through the surface. On the image plane (wafer surface), there is a problem that the amount of light is reduced to about 10%. In addition, in Japanese Patent Application Laid-Open Nos. 9-213332 and 10-90602, a configuration using only a reflection system is basically used, but there is a problem that aberration (Petzbar sum) is deteriorated and mirror arrangement is difficult. Due to problems and the like, it is difficult to secure a sufficient imaging region width on the image plane. In addition, a concave mirror with high power in the vicinity of the image plane has an image forming function, so it is difficult to increase the NA, and since the convex mirror is placed immediately before the concave mirror, sufficient image-side operation is possible. There is a problem that the distance cannot be secured. Japanese Patent Application Laid-Open Nos. 62-210415 and 62-258414 apply a Cassegrain-type or Schwarzschild-type mirror system, and provide an aperture in the center of the mirror to cause a pupil in the middle. We have proposed an optical system that contributes only to the periphery of the pupil for imaging, but there is a concern about the effect of pupil hollowing on the imaging performance, and trying to reduce pupil hollowing will inevitably cause Since the power increases, the incident / reflection angle to the mirror also increases, and when the NA is further increased, the diameter of the mirror is remarkably increased. In JP-A-5-188298 and JP-A-6-230287, the configuration is complicated due to bending of the optical path, and the concave mirror bears most of the power of the optical group that forms the intermediate image into the final image. Therefore, it is difficult to increase the NA due to the structure, and the magnification of the lens system arranged between the concave mirror and the image plane is a positive sign in the reduction system, so that a sufficient image-side working distance cannot be secured. In addition, it is difficult to secure the imaging region width because of the necessity of dividing the optical path, and the footprint is not preferable because the optical system is enlarged.

  In JP-A-2-66510 and JP-A-3-282527, since the optical path is first divided by a beam splitter, the lens barrel structure becomes complicated. When a beam splitter having a large diameter is required and this is a prism type, the light amount loss is large due to its thickness. When the NA is high, the diameter is further increased, so that the light loss is further increased. When the beam splitter is a flat plate type, there is a problem in that astigmatism and coma aberration are generated even on axial rays. In addition, generation of asymmetrical aberration due to heat absorption and generation of aberration due to characteristic changes on the light beam splitting surface are caused, and it is difficult to produce a beam splitter with high accuracy on the manufacturing surface.

  Japanese Patent Application Laid-Open Nos. 10-3039 and 2000-47114 are two-time imaging catadioptric optical systems that form an intermediate image once, and have a reciprocating optical system including a concave mirror and an object (reticle). ), And a second imaging optical system that forms the intermediate image on the second object (wafer) surface. In Japanese Patent Application Laid-Open No. 10-3039, a first plane mirror for deflecting the optical axis and the light beam is disposed in the vicinity of the intermediate image. The bent optical axis is deflected substantially parallel to the reticle stage and deflected again by the second plane mirror, or imaged onto the second object without the second plane mirror. Japanese Patent Laid-Open No. 2000-47114 discloses that a light beam from a first object (reticle) is refracted by a positive lens and immediately deflected by a first plane mirror and reflected by a reciprocating optical system including a concave mirror. The deflected light beam is again deflected by the second plane mirror in the first imaging optical system, and an intermediate image is formed. The intermediate image is projected onto the second object (wafer) by the second imaging optical system. Therefore, in both publications, the first object plane (reticle), the lens, the plane mirror, and the deflected light beam are inevitably disposed, and the first object plane (reticle) and the reticle stage; Interference with the lens and the flat mirror becomes a problem, and it is difficult to secure a sufficient space.

  The optical system shown in FIG. 13 of Japanese Patent Application Laid-Open No. 2002-83766 and the optical systems shown in FIGS. 7 and 9 of Japanese Patent Application Laid-Open No. 8-62502 are three-time imaging catadioptric optical systems that form an intermediate image twice. A first imaging optical system for forming a first intermediate image of a first object (reticle); a second imaging optical system for forming a second intermediate image from the first intermediate image and having a concave mirror; And a third imaging optical system that forms an intermediate image of 2 on the second object plane (wafer). Since the second imaging optical system has a concave mirror, it has a reciprocating optical system. In the former optical system of NA0.75 in FIG. 13 of Japanese Patent Laid-Open No. 2002-83766, a plane mirror (reflection block) is disposed in the vicinity of the first and second intermediate images, and the optical axes of the first and third imaging optical systems. Thus, the first object (reticle) and the second object (wafer) are arranged in parallel. However, for higher NA, there is a problem that the total length (distance between the first object and the second object) becomes large due to aberration correction. In addition, since it is necessary to arrange a plane mirror (reflection block) for deflecting the light beam in the vicinity of the position of the first and second intermediate images, the influence of dust and scratches on the two plane mirror surfaces on the imaging performance Is big. In addition, since the reduction magnification is greatly increased in the first imaging optical system, the NA of the first intermediate image is equal to the reduction magnification in the first intermediate image with respect to the object side NA of the first object (reticle). As a result, the incident angle range to the plane mirror becomes large. This becomes a more serious problem with higher NA. That is, since the first imaging optical system bears too much reduction magnification due to the further high NA, the incident angle range to the plane mirror becomes very large, and the reflection intensity of P and S due to the influence of the film of the plane mirror. As a result, a large difference occurs. The optical system of NA 0.45 to 0.5 in FIGS. 7 and 9 of the latter Japanese Patent Laid-Open No. 8-62502 is also a catadioptric projection optical system that forms an image three times, that is, an intermediate image twice. It is. In the case of this type of projection optical system, it is necessary to use another plane mirror in order to arrange the first object (reticle) and the second object (wafer) in parallel. In that case, as described in the aforementioned publication, a mirror must be arranged in the first imaging optical system, and if it is arranged in the vicinity of the first intermediate image, the above-mentioned Japanese Patent Application Laid-Open No. 2002-83766. The arrangement is similar to that of the optical system shown in FIG. Further, the reduction magnification in the first imaging optical system and the second imaging optical system places a heavy burden on the overall reduction magnification, and the attempt to achieve further higher NA results in the former JP-A-2002-83766. It becomes a fatal problem like the optical system of No. 1 publication.

  Therefore, the present invention provides a projection optical system capable of easily securing a space near the first object (reticle), having a simple mechanical configuration, and minimizing the influence of a film on a plane mirror, and the projection An object of the present invention is to provide a projection exposure apparatus and a device manufacturing method using an optical system.

In order to solve the above-described problem, a projection optical system according to one aspect of the present invention includes at least one optical path along the optical path from the first object side (in the order in which light emitted from the first object side passes). A first imaging optical system having a lens and forming a first intermediate image of the first object; at least one lens and at least one concave mirror; and forming a second intermediate image of the first object. A second imaging optical system and at least one lens, a third imaging optical system for forming an image of the first object on the second object, and an image of the first object Is a catadioptric projection optical system that forms an image on the second object, having at least one deflecting / reflecting member, the paraxial magnification of the first imaging optical system being β1, and the second imaging optical When the paraxial magnification of the system is β2,
0.70 <| β1 · β2 | <3.0
It is characterized by satisfying. Preferably,
0.80 <| β1 · β2 | <2.0
It is still better to meet.

further,
0.70 <| β1 | <2.0
0.70 <| β2 | <2.0
It is characterized in that at least one of them is satisfied. More preferably,
0.80 <| β1 | <1.5
0.80 <| β2 | <1.5
It is even better if at least one of them is met.

A projection optical system according to another aspect of the present invention is a projection optical system that projects an image of a first object onto a second object, and at least one lens in order from the first object side. A first imaging optical system for forming a first intermediate image of the first object, at least one lens and at least one concave mirror, and a second intermediate image of the first object A second imaging optical system to be formed; and a third imaging optical system having at least one lens and forming an image of the first object on the second object. When the paraxial magnification of the optical system is β1, the paraxial magnification of the second imaging optical system is β2, and the numerical aperture on the first object side of the projection optical system is NAo,
3.5 <| β1 · β2 | / NAo <20
It is characterized by satisfying. Where
4.0 <| β1 · β2 | / NAo <10
It is desirable to satisfy

When the numerical aperture on the second object side of the projection optical system is NA,
1. 1 <NA <1.6
It is desirable to satisfy

When the Petzval sum of the first imaging optical system is P1, the Petzval sum of the second imaging optical system is P2, and the Petzval sum P3 of the third imaging optical system,
P1> 0, P2 <0, P3> 0
It is characterized by satisfying.

In addition, the second imaging optical system has one concave mirror, the effective diameter of the one concave mirror is φM1, and the most off-axis principal ray emitted from the first object is incident on the concave mirror. When the height from the optical axis of the first imaging optical system is hM1,
0 ≦ | hM1 / φM1 | <0.10
It is characterized by satisfying.

The first deflecting / reflecting member that reflects the reflected light from the concave mirror of the second imaging optical system and the first deflecting / reflecting member are arranged at an angle of approximately 90 degrees, and the first deflecting / reflecting member A second deflecting / reflecting member that reflects the reflected light and guides the reflected light to the second object side, between the optical axis of the first imaging optical system, the second deflecting / reflecting member, and the second object. Y is the distance from the optical axis of the optical system, φGr2_max is the maximum effective diameter in the second imaging optical system, and φL3B_max is the maximum effective diameter in the optical system between the second deflection reflecting member and the second object. And when
0.2 <(φGr2_max + φL3B_max) / (2Y) <0.9
It is characterized by satisfying.

A first deflecting / reflecting member that reflects the reflected light from the concave mirror of the second imaging optical system; a principal ray from the off-axis of the first object; and a reflecting surface of the first deflecting / reflecting member. When the angle between the normal and is θp,
20 ° <θp <45 °
It is characterized by satisfying. Here, it is preferable to configure so as to satisfy 30 ° <θp <44 °.

  Further, it is preferable that the concave mirror is disposed to face the first object.

  Further, in the optical path from the concave mirror of the second imaging optical system to the second object plane, two of the deflection reflection members are arranged, and each of the two deflection reflection members has The normals of the reflecting surfaces are preferably substantially at an angle of 90 degrees with respect to each other normal.

  Further, the deflecting reflecting member is a reflecting mirror.

  A catadioptric projection optical system that forms an image of the first object on the second object after forming an intermediate image of the first object twice, and an optical path from the first object side. (In the order in which light emitted from the first object passes), a first imaging optical system having at least one lens, a first deflecting / reflecting member, and a refractive lens in order from the first object side Group, and a concave mirror (having a first deflecting / reflecting member, a refractive lens group, and a concave mirror in order from the side closer to the first object, that is, from the side closer to the first object regardless of the optical path) An imaging optical system, a third imaging optical system having at least one lens and a second deflecting / reflecting member having a normal that is substantially 90 degrees with respect to the normal of the first deflecting / reflecting member The first object and the concave mirror are arranged to face each other, and The light beam from one imaging optical system is reflected in the order of the concave mirror and the first deflecting / reflecting member and guided to the third imaging optical system, and the first deflecting / reflecting member reflects the first deflecting / reflecting member. The light beam from the member is deflected and guided to the second object.

  A catadioptric projection optical system that forms an image of the first object on the second object after forming an intermediate image of the first object twice, and an optical path from the first object side. (In the order in which light emitted from the first object side passes), the first imaging optical system having at least one lens, the first deflecting / reflecting member in order from the first object side, refraction A lens group and a concave mirror (having a first deflecting reflection member, a refractive lens group, and a concave mirror in order from the side closer to the first object, that is, from the side closer to the first object regardless of the optical path) A second imaging optical system, and a third imaging optical system having at least one lens. The first object and the concave mirror are arranged to face each other, and the light beam from the first imaging optical system to the concave mirror And the light flux reflected by the first deflecting / reflecting member intersect with each other. It is characterized in that it has arranged in a predetermined angle direction reflecting member with respect to the optical axis of the second imaging optical system.

  The exposure apparatus according to the present invention may be any one of the above, wherein an illumination optical system that illuminates the first object with light from a light source, and projects light from the first object onto the second object. And the catadioptric projection optical system described above.

  According to another aspect of the present invention, there is provided a device manufacturing method comprising: an exposure step of exposing the second object using the exposure apparatus described above; and a developing step of developing the exposed second object. Yes.

  According to the catadioptric projection optical system of the present invention, it is possible to easily solve the problem of the space between the first object plane (reticle) and the lenses and reflection mirrors constituting the optical system, and it is important for increasing the NA. A high-NA catadioptric optical system capable of suppressing the influence of the reflecting mirror film, which is a serious problem, without shielding the pupil and obtaining a sufficiently large imaging region width on the image plane, and the projection A projection exposure apparatus and a device manufacturing method using an optical system can be obtained.

  A catadioptric projection optical system as one aspect of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to these examples, and each component may be alternatively substituted and a laser is used as the light source as long as the object of the present invention is achieved. However, it is not necessarily limited to this, and a lamp such as a mercury lamp or a xenon lamp can also be used. In the drawings, the same members are denoted by the same reference numerals, and redundant description is omitted. Here, FIG. 1 is a schematic view of a catadioptric projection optical system as one aspect of the present invention. 101 is a first object (reticle), 102 is a second object (wafer), and AX1 to AX3 are optical axes of the optical system. The optical system here includes a first imaging optical system Gr1, a second imaging optical system Gr2, and a third imaging optical system Gr3 in the order in which light rays pass from the object side. The first imaging optical system Gr1 forms an image of the first object 101 (first intermediate image IMG1), and a light beam from the first intermediate image IMG1 has a second connection having a concave mirror M1 and a reciprocating optical system portion L2. A second intermediate image IMG2 is formed by the image optical system Gr2. At this time, the light beam and the optical axis AX1 reflected in the direction of the first object 101 by the reciprocating optical system portion L2 of the second imaging optical system Gr2 are deflected by the first deflecting / reflecting member FM1. The third imaging optical system Gr3 forms an image of the intermediate image IMG2 on the second object 102 with a predetermined magnification. At that time, the light beam reflected from the first deflection reflection member FM1 is deflected by the second deflection reflection member FM2 included in the third imaging optical system. Accordingly, the optical axis AX2 is deflected like the optical axis AX3.

  By adopting the three-fold imaging optical system in this way and deflecting the light beam by the concave mirror M1 included in the second imaging optical system Gr2 and the deflecting reflecting members FM1 and FM2, the first object 101, the lens, and the deflection In addition to avoiding interference with reflecting members, etc., the three-time imaging optical system has a small distance between object images and a small effective diameter. An optical system can be achieved.

  Here, the second imaging optical system Gr2 has a concave mirror M1, and also has a reciprocating optical system portion (L2 in the figure) through which the light beam reciprocates. The concave mirror M1 is the same as the first imaging optical system Gr1 and is on one linear optical axis AX1, and is disposed so that the concave surface faces the reticle surface. The light beam reflected by the concave mirror M1 in the second imaging optical system Gr2 passes through the reciprocating optical system portion L2 in the second imaging optical system Gr2, and then the optical axis AX1 is changed to AX2 by the first deflection reflecting member. Bend 90 degrees. At this time, the deflecting / reflecting member is set to a predetermined axis with respect to the optical axis so that the light beam from the first imaging optical system to the concave mirror and the light beam reflected from the concave mirror and reflected by the deflecting / reflecting member intersect each other. It is arranged with an angle. The light beam reflected by the first deflecting / reflecting member FM1 is arranged by bending the optical axis AX2 by 90 degrees like AX3 by the second deflecting / reflecting member FM2 arranged in the third imaging optical system Gr3. . In this way, the first object 101 and the second object 102 are arranged in parallel by bending the optical axis twice by two deflecting and reflecting members. Accordingly, the first deflecting reflecting member and the second deflecting reflecting member in FIG. 1 are disposed with an angle difference of 90 degrees relative to the reflecting surface. FIG. 1 shows a state where a light beam emitted from an object height off the axis of the first object 101 is imaged on the second object surface 102, but the present invention is directed to the optical axis AX1 of the first object. The light beam emitted from the off-axis object height within a certain range is used. At this time, a pattern of a rectangular slit area that does not include the optical axis or an arc-shaped slit area (exposure area) that does not include the optical axis is exposed on the second object 102.

  The first imaging optical system Gr1 has a negative focal length, and has at least one lens. The second imaging optical system Gr2 has a positive focal length, and has at least one lens and a concave mirror M1. The third imaging optical system Gr3 has a negative focal length and has at least one lens. The chromatic aberration and the positive Petzval sum generated by the first imaging optical system Gr1 and the third imaging optical system Gr3 are corrected by the concave mirror M1 and the lens of the second imaging optical system Gr2.

  In the embodiment of the present invention, the focal length of the first imaging optical system Gr1 is negative, the focal length of the second imaging optical system Gr2 is positive, and the focal length of the third imaging optical system Gr3 is negative. It is not limited to this. The first to third imaging optical systems may each have a focal length that is negative, positive, or infinite. Therefore, all combinations of the three focal lengths (negative, positive, and infinity) that the first to third imaging optical systems can take are conceivable.

Further, when the paraxial imaging magnification of the first imaging optical system Gr1 is β1, and the paraxial imaging magnification of the second imaging optical system Gr2 is β2, it is preferable that the following conditional expression is satisfied.
0.70 <| β1 · β2 | <3.0 to (1)
If the lower limit value of conditional expression (1) is not satisfied, the combined magnification of the first imaging optical system Gr1 and the second imaging optical system Gr2 becomes too small, resulting in one of the following states (A) to (C). It is not preferable.
(A) A light beam that is reflected by the light beam deflecting / reflecting member FM1 and travels in the direction of the third imaging optical system Gr3, and a light beam that enters the second imaging optical system Gr2 from the first imaging optical system Gr1. (B) The paraxial magnification β2 of the second image-forming optical system Gr2 becomes too much a reduction magnification, and asymmetric aberrations are particularly generated in the reciprocating optical system portion. The imaging performance is deteriorated.
(C) Especially in an optical system having a high NA, the incident angle range of light incident on the deflecting / reflecting member for the purpose of deflection becomes large. This is because the first and second imaging optical systems bear a considerable reduction magnification, and the spread of the light beam emitted from the first object, that is, the object side NA is increased by the reduction magnification by the first and second imaging optical systems. This is because the incident angle range of the light beam incident on the first deflecting / reflecting member is increased. As a result, there is a large difference in the reflection intensity between P and S due to the influence of the reflection film of the deflecting reflection member. This is particularly noticeable in a catadioptric projection optical system having multiple imaging with NA of 0.8 or more, more specifically NA of 0.85 or more.

  If the upper limit value of the conditional expression (1) is exceeded, the combined magnification of the first and second imaging optical systems is too large. Considering the case where the first object 101 is reduced and projected onto the second object 102, The absolute value of the paraxial imaging magnification β3 of the three-imaging optical system Gr3 becomes too small, making it difficult to correct aberrations. In addition, the effective diameter of the lens near the second intermediate image IMG2 becomes too large.

More preferably, the following conditional expression should be satisfied.
0.80 <| β1 · β2 | <2.0 to (2)
Further, it is preferable that the following conditional expression is satisfied.
0.70 <| β1 | <2.0 to (3)
0.70 <| β2 | <2.0 to (4)
If the lower limit of conditional expression (3) is not satisfied, the imaging magnification β1 of the first imaging optical system Gr1 becomes too small, and the light beam near the first intermediate image IMG1, which is the image of the first object 101, The deflecting / reflecting member FM1 interferes and the light beam is scattered. If the upper limit is exceeded, the first intermediate image IMG1 becomes too large, the effective diameter of the lens in the vicinity of the first intermediate image IMG1 becomes large, and the magnification in the other imaging optical systems Gr2, 3 This is not preferable because it increases the burden. If the conditional expression (4) is not satisfied, the magnification will deviate greatly from the same magnification. Therefore, since the second imaging optical system Gr2 has a reciprocating optical system having a strong power, the symmetry is greatly lost, and it becomes difficult to correct the asymmetric aberration.

More preferably, the following conditional expression should be satisfied.
0.80 <| β1 | <1.5 to (5)
0.80 <| β2 | <1.5 to (6)
By satisfying conditional expressions (5) and (6), the magnification burden of the first to third imaging optical systems can be made more appropriate, and an optical system with a smaller effective diameter and better performance can be obtained. It is easy to achieve. If the magnification β1 of the first imaging optical system is equal to or greater than 1, the light beam separation between the first deflecting / reflecting member FM1 and the light beam having the lowest angle of view of the first imaging optical system Gr1 becomes easier. There is also an advantage that the maximum angle of view can be lowered.

Further, the positive Petzval sum generated by the refractive optical system portions of the first imaging optical system Gr1 and the third imaging optical system Gr3 has a negative refractive power of the reciprocating optical system portion in the second imaging optical system Gr2. It can be completely corrected by the negative Petzval sum generated by the lens unit L2 and the concave mirror M1. At this time, the Petzval sum P1 of the first imaging optical system, the Petzval sum P2 of the second imaging optical system, and the Petzval sum P3 of the third imaging optical system are P1> 0, P2 <0, P3> 0 to ( 7)
By satisfying the above conditions, the imaging optical system having the concave mirror M1 and the reciprocating optical system portion L2 can be arranged as the second imaging optical system, and a symbolic optical system having a small field curvature is achieved. It becomes possible. If the conditional expression (7) is not satisfied, the concave mirror M1 and the reciprocating optical system portion L2 are arranged as the first or third imaging optical system. In the former case, the reflected light beam from the concave mirror M1 is the first. Therefore, physical interference between the first object (for example, the reticle), the returned light beam and the nearby lens is likely to occur, and the mechanical configuration becomes difficult. In the latter case, the concave mirror M1 is used in the final image forming system (third image forming optical system), and the light beam cannot be separated if an attempt is made to achieve a high NA optical system.

Moreover, when it has an arrangement as shown in FIG. 1, it is preferable to satisfy the following conditional expression.
0.2 <(φGr2_max + φL3B_max) / (2Y) <0.9 to (8)
Here, the distance between the optical axes AX1 and AX3 is Y, φGr2_max is the maximum effective diameter in the second imaging optical system Gr2, and φL3B_max is the second deflecting / reflecting member FM2 and the second object in the third imaging optical system Gr3. The maximum effective diameter in the lens unit L3B located between the lens 102 and the lens 102 is shown. If the lower limit value of conditional expression (8) is not satisfied, the distance between the optical axes AX1 and AX3 will be too large, and the effective diameter of the third imaging optical system Gr3 will be excessively large. When the upper limit is exceeded, the distance between the optical axes AX1 and AX3 is too short, and the lens or concave mirror M1 of the second imaging optical system Gr2 interferes with the lens group L3B of the third imaging optical system Gr3, or the lens barrel. Can no longer be configured.

Further, when the effective diameter of the concave mirror M1 is φM1, and the height of the most off-axis principal ray from the optical axis AX1 in the concave mirror M1 is hM1,
−0.10 <hM1 / φM1 <0.10 to (9)
It is preferable that Thus, by arranging the concave mirror M1 of the second imaging optical system Gr2 in the vicinity of the pupil, it is possible to avoid the occurrence of astigmatism and the like.

  The catadioptric optical system of the present invention has at least one deflecting / reflecting member. In the case of having two deflecting and reflecting members, it is preferable to arrange one in the second imaging optical system Gr2 and one in the third imaging optical system Gr3. In particular, the light beam from the first imaging optical system Gr1 is preferably reflected so as to be reflected by the concave mirror M1 after being incident on the second imaging optical system Gr2, and then reflected by the first deflecting / reflecting member. That is, after the light beam from the first object 101 forms the first intermediate image IMG1 by the first imaging optical system Gr1, it is reflected by the concave mirror M1 after entering the reciprocating optical system portion L2 in the second imaging optical system Gr2. Then, it is preferable to arrange the first deflecting / reflecting member so as to reflect the light beam incident on L2 again and emitted from L2.

  If the deflecting / reflecting member is disposed in the vicinity of the first intermediate image IMG1 on which the light beam from the first imaging optical system Gr1 forms an image before entering the second imaging optical system Gr2, the concave mirror M1 becomes the first mirror. It becomes impossible to arrange in parallel with the object 101. Then, when the direction of gravity is matched with the optical axis AX1, the deterioration of the imaging performance due to the self-weight deformation of the concave mirror M1 and the reciprocating optical system L2 having strong refractive power or the suppression of the lens barrel or the like becomes remarkable. . Two deflecting / reflecting members may be included in the third imaging optical system Gr3. In that case, the first deflecting / reflecting member FM1 is disposed immediately after the second imaging optical system Gr2 forms the intermediate image IMG2 or after passing through the lens.

  The second deflecting / reflecting member FM2 is disposed in a space until the light beam reflected by the first deflecting / reflecting member FM1 reaches the second object. In that case, it is possible to downsize the deflecting / reflecting member by having at least one lens (preferably having a positive refractive power) between the first deflecting / reflecting member FM1 and the second deflecting / reflecting member FM2. This is desirable because it can be done, but it is not necessary.

  Further, as shown in FIG. 1, it is desirable that there is no lens between the light beams incident on the reciprocating optical system portion L2 of the second imaging optical system Gr2 after forming the first intermediate image IMG1, that is, between IMG1 and L2. . If a lens is present in a space other than the reciprocating optical system portion L1 after the first intermediate image IMG1 is formed, it may be difficult to place the deflecting / reflecting member FM1 and the lens too close to each other. However, even if they are close to each other, they may be arranged as long as the mechanical configuration is possible.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2. The L2 has a negative refractive power and has at least one refractive lens having a negative refractive power. The second imaging optical system Gr2 preferably includes at least one lens (preferably two or more) having a negative refractive power and having a concave surface facing the first object 101. The reciprocating optical system portion L2 preferably has at least one lens having an aspherical surface. If an aspheric surface is not used, it is preferable to share power using a plurality of lenses for the reciprocating optical system portion L1. Of course, even when an aspherical surface is used, it is possible to better suppress the occurrence of aberrations in the reciprocating optical system portion by using a plurality of aspherical surfaces. The concave mirror may be aspherical.

  The second imaging optical system Gr2 may include at least one lens other than the reciprocating optical system portion L2 and the concave mirror M1. Specifically, there is a second intermediate image IMG2 between the first deflecting / reflecting member FM1 and the second deflecting / reflecting member FM2, and a lens between the first deflecting / reflecting member FM1 and the second intermediate image IMG2. Is present. In that case, the effective diameter of the lens near the second intermediate image IMG2 can be reduced.

  The third imaging optical system Gr3 includes at least one refractive member, and includes a lens group L3A having a positive refractive power and a lens group L3B having at least one refractive member and having a positive refractive power. Then, an image of the second intermediate image IMG2 is formed on the second object 102. At this time, a lens group having a negative refractive power may be included in the L3B group. Also, by arranging the second deflecting / reflecting member between the lens groups L3A and L3B, the first object 101 and the second object 102 can be arranged in parallel. Of course, a second deflecting / reflecting member may be disposed between the second intermediate image IMG2 and the lens unit L3A.

  The deflecting / reflecting member is composed of a deflecting / reflecting mirror. The shape of the mirror may be a flat plate shape or a part of a cube shape. Further, a reflection mirror using the back surface reflection of glass may be used. A beam splitter may be used. In that case, off-axis luminous flux can be used from on-axis.

Further, as shown in the arrangement of FIG. 1, the light beam from the first imaging optical system Gr1 to the concave mirror M1 and the light beam reflected from the concave mirror M1 and then reflected from the first deflecting reflection member intersect. One deflecting / reflecting member may be arranged with a predetermined angle with respect to the optical axis. With this arrangement, the incident angle of the chief ray incident on the first deflecting / reflecting member FM1 can be reduced, so that the maximum incident angle on the first deflecting / reflecting member FM1 can be reduced. . The following conditional expression is preferably satisfied.
20 ° <θp <45 ° (10)
In the equation (10), θp is an angle formed between the principal ray from the off-axis of the first object and the normal line of the reflecting surface of the first deflecting / reflecting member FM1. If the lower limit value of conditional expression (10) is not satisfied, the angle formed between the normal line of the reflecting surface of the deflecting reflecting member and the principal ray becomes too small, the deflecting reflecting member becomes too large, or the refractive power of the surrounding lenses is reduced. The performance deteriorates because it has to be strengthened abnormally. If the upper limit value is exceeded, the angle of the light beam input to the deflecting / reflecting member becomes large, so that the film characteristics deteriorate as described above. More preferably, it is preferable to configure so as to satisfy the following expression (11).
30 ° <θp <44 ° to (11)
The first deflecting / reflecting member FM1 prevents the optical path from the first imaging optical system Gr1 and reaching the concave mirror M1 from intersecting the optical path reflected by the first deflecting / reflecting member and reaching the second deflecting / reflecting member. Can also be arranged. That is, it may be arranged as shown in FIG.

  The first object 101 and the second object 102 are preferably arranged in parallel, but this need not be the case. That is, as shown in FIG. 8, the optical system may be configured without the second deflecting / reflecting member FM2.

  The aperture stop 103 is preferably arranged in the lens unit L3B of the third imaging optical system Gr3. Further, the principal ray of the first imaging optical system Gr1 may be arranged near the intersection with the optical axis AX1 simultaneously or independently.

  In FIG. 1, the optical axes AX1 and AX2 and the optical axes AX2 and AX3 are arranged orthogonally, but as shown in FIG. 2, the optical axes AX1 to AX3 are not necessarily orthogonal. Desirably, the deflecting and reflecting members FM1 and FM2 are arranged so that their reflecting surfaces have an angle difference of 90 degrees. This is because the first object 101 and the second object 102 can be arranged in parallel if they are arranged with a relative angle difference of 90 degrees. However, when it is not necessary to arrange the first object 101 and the second object 102 in parallel, it is not necessary to have an angle difference of 90 degrees relatively, so an arbitrary angle may be taken.

  Further, in order to prevent the magnification from changing even if the second object plane fluctuates in the optical axis direction, it is preferable that at least the image plane side is configured to be telecentric. The imaging optical system of the present invention is particularly effective when it has a very high NA of 0.8 or more, and further NA of 0.85 or more.

  The optical system of the present invention can have an aberration correction mechanism. For example, the first imaging optical system Gr1 can have a mechanism for moving the lens in the optical axis direction and / or moving the lens in the direction perpendicular to the optical axis or other direction (decentering the lens). . The second image forming optical system Gr2 and the third image forming optical system Gr3 may have a similar aberration correction mechanism. Further, aberration correction may be performed by providing a mechanism for deforming the concave mirror M1.

  In addition, a so-called immersion configuration is adopted in which the space between the second object surface 102 and the final glass surface of the optical system (between the second object surface 102 and the lens L326 in FIG. 3 described later) is filled with liquid. Good.

  A field stop may be provided in the vicinity of the intermediate imaging IMG1 and IMG2. A field stop may be provided in the vicinity of the second object plane 102. In particular, when a diffractive optical element is used in the optical system and the vicinity of the second object surface is configured by immersion as described above, a diaphragm for limiting the field of view is provided on the final glass surface of the optical system, When a field stop is disposed in the vicinity thereof (for example, between the final glass surface and the second object surface 102), flare light generated in the diffractive optical element or the like (flare light generated due to other than the diffractive optical element) Can be prevented from reaching the second object plane.

  Further, the second object plane can be formed by immersion without using a diffractive optical element in the optical system. When configuring an immersion optical system, it is necessary to minimize the influence of the liquid characteristics on the imaging performance of the optical system regardless of the presence or absence of the diffractive optical element. The distance on the optical axis between the surface and the second object surface 102 is desirably 5 mm or less. More preferably, it is 1 mm or less.

  Examples of the present invention will be described below.

  FIG. 3 shows a specific configuration of the projection optical system according to Example 1 of the present invention. Here, the projection optical system projects the pattern of the first object (original image having a drawing pattern such as a reticle and mask) onto the second object plane, and the first imaging optical system and second imaging It has an optical system and a third imaging optical system. The first embodiment relates to a projection optical system. However, the present invention is not limited to this, and can also be applied to an optical apparatus having this projection optical system, particularly an exposure apparatus. The present invention can also be applied to a device manufacturing method using an exposure apparatus having an optical system.

  The first imaging optical system in FIG. 3 includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having a positive refractive power includes a meniscus negative lens L111 having a concave surface directed toward the first object side along the light traveling direction from the first object 101 side, and is substantially disposed on the first object side. A substantially plano-convex aspherical positive lens L112 having a flat surface, a substantially plano-convex positive lens L113 having a convex surface facing the first object side, and two meniscus-shaped lenses having a convex surface facing the first object side. It consists of positive lenses L114 and L115. The refractive lens unit L1B having a positive refractive power includes a meniscus aspheric negative lens L116 having a concave surface facing the first object side, and two meniscus positive lenses having a concave surface facing the first object side. L117, L118, a substantially plano-convex positive lens L119 with a substantially flat surface facing the first object side, and a substantially plano-convex aspherical positive lens L120 with a convex surface facing the first object side.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1 along the traveling direction of light from the first imaging optical system. Then, in order from the first object side, a substantially plano-concave lens L211 having a concave surface facing the first object side, a meniscus aspheric lens L212 having a concave surface facing the first object side, and a concave surface facing the first object side. It consists of a concave mirror M1 directed.

  After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. good. In this embodiment, a plane reflecting mirror is used as the deflecting reflecting member.

  The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens unit L3A having a positive refractive power includes a substantially plano-convex aspherical positive lens having a substantially flat surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2. L311 includes two meniscus positive lenses L312 and L313 having a convex surface facing the second intermediate image IMG2. The refractive lens unit L3B having positive refractive power includes a meniscus positive lens L314 having a concave surface directed toward the second object 102, a biconcave aspheric negative lens L315, and a convex surface directed toward the second object. A meniscus negative lens L316, a meniscus aspheric negative lens L317 with a concave surface facing the second object side, a meniscus positive lens L318 with a convex surface facing away from the second object side, a substantially flat surface A substantially plano-convex aspherical positive lens L319 directed to the second object side, a meniscus negative lens L320 having a concave surface directed opposite to the second object side, an aperture stop 103, and a biconvex aspherical surface A positive lens L321, a meniscus positive lens L322 with a concave surface facing the second object side, a substantially planoconvex aspherical positive lens L323 with a substantially flat surface facing the second object side, and a concave surface facing the second object side For Aspheric positive lens L324 of a meniscus shape, a negative lens having a meniscus shape with its concave surface oriented toward the second object side L325, a positive lens of a plano-convex shape with its plane to the second object plane L326, becomes more.

  Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3. In this embodiment, the deflecting / reflecting member FM2 is a plane reflecting mirror, and bends the light beam reflected from the first deflecting / reflecting member in a predetermined direction.

  In the present embodiment, the first imaging optical system Gr1 is composed of the L1A group and the L1B group having positive refractive power, but is not limited to this optical arrangement. For example, a positive / negative / positive three-group structure, a negative / positive / negative four-group structure, or another structure may be used. Further, the third imaging optical system Gr3 has an optical arrangement such as L3A having a positive refractive power and L3B having a positive refractive power, but is not limited thereto. The L3B group may have a lens group having a negative refractive power, or may have another configuration.

  In this embodiment, the projection magnification is 1/4, the reference wavelength is 157 nm, and fluorite is used as the glass material.

  The numerical aperture on the image side is NA = 0.87, and the distance between the object images (the first object plane to the second object plane) is L = 1484 mm. In addition, aberration correction is performed in an image height range of about 4.25 to 16.63 mm, and a rectangular exposure region of at least 26 mm in the length direction and about 6 mm in width can be secured. The aperture stop 103 is disposed between L320 and L321.

  Further, a lateral aberration diagram of this example is shown in FIG. Here, the drawing with Y = 4.25 shows a lateral aberration diagram of light from an off-axis region with an image height of 4.25 mm in the first object, and Y = 16.625 is the first figure. The lateral aberration figure of the light from the off-axis area | region whose image height in an object of 1 is 16.625 mm is shown. FIG. 5 shows the reference wavelengths of 157.6 nm and ± 0.6 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  In the present embodiment, only fluorite is used as the glass material to be used, but other glass materials such as barium fluoride and magnesium fluoride may be used simultaneously or independently. In the case of using the 193n wavelength (ArF), quartz and fluorite may be used at the same time, or only quartz may be used. Further, other glass materials may be used.

The following (Tables 1 and 2) show the configuration specifications of the numerical embodiment of Example 1. In the table, i is a surface number along the traveling direction of light from the first object 101, ri is a radius of curvature of each surface corresponding to the surface number, and di is a surface interval between the surfaces. The lens glass material CaF2 has a refractive index of 1.56 with respect to the reference wavelength λ = 157.6 nm. Further, the refractive indexes of the wavelengths of +0.6 pm and −0.6 pm with respect to the reference wavelength are 1.55999853 and 1.560000147, respectively. In addition, the shape of the aspherical surface is
^{X = (H 2/4)} / (1 + ((1- (1 + k) · (H / r) 2)) 1/2) + AH 4 + BH 6 + CH 8 + DH 10 + EH 12 + FH 14 + GH 16
Shall be given in Here, X is the amount of displacement in the optical axis direction from the lens apex, H is the distance from the optical axis, ri is the radius of curvature, k is the conic constant, and A, B, C, D, E, F, and G are aspherical surfaces. It is a coefficient.

  The specific lens configuration of Example 2 is shown in FIG. The first imaging optical system in the figure includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having a positive refractive power includes a meniscus negative lens L111 having a concave surface directed toward the first object side along the light traveling direction from the first object 101 side, and is substantially disposed on the first object side. A substantially plano-convex aspherical positive lens L112 facing the plane, a substantially plano-convex positive lens L113 having a convex surface facing the first object side, a biconvex positive lens L114, and a convex surface facing the first object side. It is composed of a meniscus positive lens L115 directed toward it. The refractive lens unit L1B having a positive refractive power includes a meniscus aspheric negative lens L116 having a concave surface facing the first object side, and three meniscus positive lenses having a concave surface facing the first object side. L117, L118, and L119 and a substantially plano-convex aspherical positive lens L120 having a convex surface facing the first object side.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1. Then, along the traveling direction of light from the first imaging optical system Gr1, a substantially plano-convex positive lens L211 having a convex surface facing the concave mirror M1, and a meniscus negative lens L212 having a concave surface facing the first object side. , A substantially plano-concave lens L213 with the concave surface facing the first object side, a meniscus aspheric lens L214 with the concave surface facing the first object side, and a concave mirror M1 with the concave surface facing the first object side. After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. The second intermediate image IMG2 may be positioned between the reciprocating optical system portion L2 and the deflecting / reflecting member FM1. In this embodiment, a plane reflecting mirror is used as the deflecting reflecting member.

  The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens unit L3A having a positive refractive power includes a substantially plano-convex aspherical positive lens having a substantially flat surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2. L311 includes two meniscus positive lenses L312 and L313 having a convex surface facing the second intermediate image IMG2. The refractive lens unit L3B having positive refractive power includes a meniscus positive lens L314 having a concave surface directed toward the second object 102, a biconcave aspheric negative lens L315, and a concave surface directed toward the second object. A meniscus aspheric negative lens L316, a substantially planoconvex positive lens L317 with the convex surface facing away from the second object side, a biconvex aspheric positive lens L318, and a concave surface as the second object side Is a negative meniscus lens L319 facing toward the opposite side, an aperture stop 103, a biconvex aspherical positive lens L320, a negative meniscus lens L321 with a concave surface facing the second object side, and a concave surface facing the second object. Two meniscus positive lenses L322, L323 facing toward the second side, two meniscus aspherical positive lenses L324, L325 facing toward the second object side, concave surface facing toward the second object side Negative meniscus lens L326, a positive lens of a plano-convex shape with its plane to the second object plane L327, becomes more. Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3. In this embodiment, the deflecting / reflecting member FM2 is a plane reflecting mirror, and bends the light beam reflected from the first deflecting / reflecting member in a predetermined direction.

  In the present embodiment, the first imaging optical system Gr1 is composed of the lens groups L3A and L3B having positive refractive power, but is not limited to this configuration. For example, a positive / negative / positive three-group configuration or other configurations may be used.

  In this embodiment, the projection magnification is 1/4, the reference wavelength is 157 nm, and fluorite is used as the glass material. The numerical aperture on the image side is NA = 0.86, and the distance between the object images (the first object surface to the second object surface) is L = 1425 mm. In addition, aberration correction is performed in an image height range of about 3.25 to 16.5 mm, and a rectangular exposure region of at least 26 mm in the length direction and about 7 mm in width can be secured. The aperture stop 103 is disposed between L320 and L321.

  Further, FIG. 6 shows a lateral aberration diagram of this example. Here, the drawing with Y = 3.25 shows a lateral aberration diagram of light from the off-axis region where the image height of the first object is 3.25 mm, and Y = 16.5 is the first figure. FIG. 3 shows a lateral aberration diagram of light from an off-axis region with an image height of 16.5 mm in one object.

  FIG. 6 shows the reference wavelengths of 157.6 nm and ± 0.6 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  The following (Tables 3 and 4) show the configuration specifications of the numerical embodiment of Example 2. The explanation of the symbols in the table is the same as (Tables 1 and 2), and is omitted here.

Next, a catadioptric projection optical system as another aspect of the present invention will be described with reference to the accompanying drawings. As described above, the same members as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted here. In the optical system of FIG. 1 (which may be the optical system of FIGS. 2, 7 and 8), the paraxial imaging magnification of the first imaging optical system Gr1 is β1, and the proximity of the second imaging optical system Gr2. When the axial imaging magnification is β2 and the numerical aperture on the first object side is NAo, the following conditional expression should be satisfied.
3.5 <| β1 · β2 | / NAo <20 to (12)
Conditional expression (12) defines the value of the combined paraxial magnification of the first and second imaging optical systems with respect to the numerical aperture NAo on the first object side. If the lower limit of conditional expression (12) is not satisfied, the combined magnification of the first imaging optical system Gr1 and the second imaging optical system Gr2 with respect to the numerical aperture on the first object side will be too small. Then, the light beam reflected by the light beam deflecting / reflecting member FM1 and separated toward the third imaging optical system Gr3 and the light beam incident on the second imaging optical system Gr2 from the first imaging optical system Gr1 are separated. The paraxial magnification β2 of the imaging optical system Gr2 is extremely reduced, and the occurrence of asymmetric aberrations particularly in the reciprocating optical system portion is large, and the imaging performance is deteriorated. In particular, in an optical system having a high NA, the incident angle range of light incident on a deflecting / reflecting member for the purpose of deflection becomes large. This is because the first and second imaging optical systems bear a considerable reduction magnification, so that the spread of the light beam emitted from the first object, that is, the numerical aperture NAo on the first object side becomes the first and second imaging. This is because the incident angle range of the light beam incident on the first deflecting / reflecting member is increased because the optical system increases the reduction magnification. As a result, there is a large difference in the reflection intensity between P and S due to the influence of the reflection film of the deflecting reflection member. This is particularly noticeable in a catadioptric projection optical system having multiple imaging with NA of more than 1, particularly NA of 1.10 or more, more specifically NA of 1.20 or more, in an immersion optical system. The immersion optical system refers to the final surface (image surface side, second object side surface) and second surface of the final element of the optical system (the optical element closest to the image plane of the projection optical system, the second object side). The optical system adopts a configuration in which the surface of the object 102 (for example, a wafer) is filled (immersed) with a liquid. In other words, the immersion optical system is a liquid between the final surface of the final element of the optical system (the surface on the image surface side of the optical element closest to the image surface) and the second object surface (image surface). This is an optical system designed on the assumption that it is satisfied by the above. When performing exposure in a state where the space between the final surface of the final element and the second object surface is filled with pure water mainly in an exposure apparatus or the like. The optical system is used for projecting and exposing an object (pattern) such as a reticle onto an object such as a wafer. If the upper limit value of conditional expression (20) is exceeded, the first object 101 becomes the second object 102 because the combined magnification of the first and second imaging optical systems is too large with respect to the numerical aperture on the first object side. When the projection is reduced, the absolute value of the paraxial imaging magnification β3 of the third imaging optical system Gr3 becomes too small, and aberration correction becomes difficult. In addition, the effective diameter of the lens near the second intermediate image IMG2 becomes too large.

More preferably, the following conditional expression should be satisfied.
4.0 <| β1 · β2 | / NAo <10 to (13)
The optical system defined by the conditional expressions (12) and (13) is not limited to the optical system shown in FIG. This is particularly effective when the first, second, and third imaging optical systems are provided, the second imaging optical system has a concave mirror, and the optical system has a deflecting / reflecting mirror.

The immersion optical system should satisfy the following conditional expression.
1. 1 <NA <1.6 to (14)
If the lower limit value of conditional expression (22) is not satisfied, it will be difficult to obtain the resolving power expected when the immersion optical system is configured with respect to the catadio system. If the upper limit is exceeded, the effective diameter of the immersion optical system becomes too large, making it difficult to manufacture a lens.

More preferably, the following conditional expression should be satisfied.
1. 2 <NA <1.5 to (15)
The conditional expressions (12) to (15) described here may be used in combination with the conditional expressions described above.

  In the following, further embodiments of the present invention will be described.

  A specific lens configuration of Example 3 is shown in FIG. The first imaging optical system in the figure includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having a positive refractive power includes a meniscus negative lens L111 having a concave surface directed toward the first object side along the light traveling direction from the first object 101 side, and is substantially disposed on the first object side. A substantially plano-convex aspherical positive lens L112 having a flat surface, a biconvex positive lens L113, a substantially plano-convex positive lens L114 having a convex surface facing the first object, and a convex surface facing the first object. It is composed of a meniscus positive lens L115 directed toward it. The refractive lens unit L1B having a positive refractive power includes a substantially planoconvex negative lens L116 having a concave surface facing the first object side, and two meniscus positive lenses having a concave surface facing the first object side. L117, L118, a substantially plano-convex positive lens L119 having a substantially flat surface facing the first object side, and a substantially plano-convex aspherical positive lens L120 having a convex surface facing the first object side.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1. Then, along the traveling direction of the light from the first imaging optical system Gr1, a substantially plano-concave negative lens L211 having a concave surface directed to the first object side, and a meniscus shape having a concave surface directed to the first object side. An aspherical concave lens L212 and a concave mirror M1 with the concave surface facing the first object side. After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. good. In this embodiment, a plane reflecting mirror is used as the deflecting reflecting member.

  The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens group L3A having a positive refractive power includes a meniscus positive lens L311 having a concave surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2, and a second intermediate lens. The lens includes a substantially plano-convex positive lens L312 having a substantially flat surface facing the image IMG2 side, and a substantially plano-convex L313 having a substantially flat surface facing the second deflection reflecting member FM2. The refractive lens unit L3B having a positive refractive power includes a meniscus positive lens L314 having a concave surface facing the second object 102, a substantially plano-concave negative lens L315 having a concave surface facing the second object 102, Bi-concave aspheric negative lens L316, two meniscus positive lenses L317, L318 with the convex surface facing away from the second object side, substantially plano-convex with the substantially flat surface facing the second object side Aspherical positive lens L319 having a shape, a substantially planoconcave negative lens L320 having a concave surface facing away from the second object side, and a substantially planoconvex aspherical positive surface having a substantially flat surface facing the second object side. Lens L321, aperture stop 103, a substantially plano-convex positive lens L322 having a convex surface facing away from the second object 102, and a substantially plano-convex shape having a convex surface facing away from the second object 102 Spherical positive lens L323, concave surface facing the second object side Aspheric positive lens L324 of a meniscus shape, a positive lens L325 planoconvex shape that is planar to the second object 102 side. Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3. In this embodiment, the deflecting / reflecting member FM2 is a plane reflecting mirror, and bends the light beam reflected from the first deflecting / reflecting member in a predetermined direction.

  In the present embodiment, a so-called immersion optical system configuration is adopted in which the space between the final lens L325 and the second object 102 is filled with a liquid. In this embodiment, pure water is used as the liquid, but other liquids may be used. Further, the refractive index of the liquid is not limited to that used in this embodiment. A liquid having a refractive index of about 1.6 may be used. When the same configuration is adopted in F2, for example, PFPE or the like may be used, or any other liquid that can be used may be used. The final lens may be a flat plate. Further, a plane plate may be used between the first object 101 and the first lens L101.

  In this embodiment, the aperture stop 103 is placed between the lenses L321 and L322, but the position is not limited to this.

  In this embodiment, the projection magnification is 1/4, the reference wavelength is 193 nm, and quartz is used as the glass material. The numerical aperture on the image side is NA = 1.20, and the distance between the object images (the first object surface to the second object surface) is L = 1663.38 mm. In addition, aberration correction is performed in an image height range of about 3.38 to 17 mm, and a rectangular exposure area of at least 26 mm in the length direction and about 7.5 mm in width can be secured. Note that the slit shape of the exposure region is not limited to a rectangle, and an arc shape or other shapes may be used. The aperture stop 103 is disposed between L321 and L322.

  Further, FIG. 13 shows a lateral aberration diagram of this example. Here, the drawing with Y = 3.38 shows a lateral aberration diagram of light from the off-axis region where the image height of the second object is 3.38 mm, and Y = 17.0 is 2 is a lateral aberration diagram of light from an off-axis region having an image height of 17.0 mm in the object 2. FIG. 13 shows the reference wavelengths of 193.0 nm and ± 0.2 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  Further, when the glass material to be used has a wavelength of 193 nm (ArF), quartz and fluorite may be used at the same time, or only quartz may be used as in this embodiment. Further, other glass materials may be used as long as they can be used. At the wavelength of 157 nm (F2), fluorite may be used, or other glass materials such as barium fluoride and magnesium fluoride may be used simultaneously or independently.

  A specific lens configuration of Example 4 is shown in FIG. The first imaging optical system in the figure includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having positive refractive power includes a meniscus negative lens L111 having a concave surface directed toward the first object side along the light traveling direction from the first object 101 side, and a biconvex aspherical positive surface. Lens L112, two biconvex positive lenses L113 and L114, a meniscus positive lens L115 with a convex surface facing the first object side, a substantially planoconvex negative lens with a concave surface facing the first object side L116. The refractive lens unit L1B having a positive refractive power includes a meniscus negative lens L117 having a concave surface facing the first object side, a meniscus positive lens L118 having a concave surface facing the first object side, and a first lens It consists of a substantially plano-convex positive lens L119 with a substantially flat surface facing the object side and a substantially plano-convex aspherical positive lens L120 with a convex surface facing the first object side. In this embodiment, fluorite is used in the first imaging optical system.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1. Then, along the traveling direction of the light from the first imaging optical system Gr1, a biconcave negative lens L211, a meniscus aspherical concave lens L212 with the concave surface facing the first object side, and the concave surface as the first object Consists of a concave mirror M1 directed to the side. After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. good. In this embodiment, a plane reflecting mirror is used as the deflecting reflecting member.

  The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens group L3A having a positive refractive power includes a meniscus positive lens L311 having a concave surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2, and a second intermediate lens. The lens includes a substantially plano-convex positive lens L312 having a substantially flat surface facing the image IMG2 side, and a substantially plano-convex L313 having a substantially flat surface facing the second deflection reflecting member FM2. The refractive lens unit L3B having a positive refractive power includes a meniscus positive lens L314 having a concave surface facing the second object 102, a substantially plano-concave negative lens L315 having a concave surface facing the second object 102, A biconcave aspheric negative lens L316, a meniscus positive lens L317 with the convex surface facing away from the second object side, and a substantially plano-convex positive lens with the substantially flat surface facing the second object side 102 L318, a biconvex aspherical positive lens L319, a substantially planoconcave negative lens L320 with the concave surface facing away from the second object side, a biconvex aspherical positive lens L321, an aperture stop 103, both A convex positive lens L322, a substantially plano-convex aspherical positive lens L323 with the convex surface facing away from the second object 102, and a meniscus aspherical positive lens L324 with the concave surface facing the second object side , The second plane A positive lens L325 plano-convex toward the object 102 side. Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3. In this embodiment, the deflecting / reflecting member FM2 is a plane reflecting mirror, and bends the light beam reflected from the first deflecting / reflecting member in a predetermined direction.

  Also in this embodiment, a configuration of a so-called immersion optical system in which the space between the final lens L325 and the second object 102 is filled with a liquid is adopted.

  In this embodiment, the projection magnification is 1/4, the reference wavelength is 193 nm, and quartz and fluorite are used as the glass material. The numerical aperture on the image side is NA = 1.30, and the distance between the object images (the first object surface to the second object surface) is L = 1759 mm. Aberration correction is performed in the image height range of about 3.0 to 14.0 mm, and a rectangular exposure area of at least 17 mm in the length direction and about 8.1 mm in width can be secured. The aperture stop 103 is disposed between L321 and L322.

  Further, a lateral aberration diagram of this example is shown in FIG. Here, the drawing with Y = 3.0 shows a lateral aberration diagram of light from the off-axis region where the image height of the second object is 3.0 mm, and Y = 14.0 is the first figure. The lateral aberration figure of the light from the off-axis area | region whose image height in the object of 2 is 14.0 mm is shown. FIG. 14 shows the reference wavelengths of 193.0 nm and ± 0.2 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  A specific lens configuration of Example 5 is shown in FIG. The first imaging optical system in the figure includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having a positive refractive power includes a meniscus negative lens L111 having a concave surface facing the first object side along the light traveling direction from the first object 101 side, and a convex surface facing the first object side. Meniscus-shaped aspherical positive lens L112, biconvex positive lens L113, and two meniscus positive lenses L114 and L115 having a convex surface facing the first object side. The refractive lens unit L1B having a positive refractive power includes a meniscus negative lens L116 having a concave surface facing the first object side, and two meniscus positive lenses L117 having a concave surface facing the first object side. L118, a substantially planoconvex positive lens L119 having a substantially flat surface facing the first object side, and a substantially planoconvex aspherical positive lens L120 having a convex surface facing the first object side.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1. Then, along the traveling direction of light from the first imaging optical system Gr1, a meniscus negative lens L211 having a concave surface directed toward the first object side, and a meniscus aspherical surface having the concave surface directed toward the first object side. The concave lens L212 includes a concave mirror M1 having a concave surface directed toward the first object side. After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. good. In this embodiment, a plane reflecting mirror is used as the deflecting reflecting member.

  The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens group L3A having a positive refractive power includes a meniscus positive lens L311 having a concave surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2, and a second intermediate lens. The lens includes a substantially plano-convex positive lens L312 having a substantially flat surface facing the image IMG2 side, and a substantially plano-convex L313 having a substantially flat surface facing the second deflection reflecting member FM2. The refractive lens unit L3B having a positive refractive power includes a meniscus positive lens L314 having a concave surface directed toward the second object 102, a biconcave aspheric negative lens L315, and a convex surface opposite to the second object side. Two meniscus positive lenses L316 and L317 facing toward the side, a substantially plano-convex aspherical positive lens L318 whose substantially plane faces toward the second object side 102, and a concave surface opposite to the second object side A negative meniscus lens L319 facing toward the surface, a substantially plano-convex aspherical positive lens L320 facing substantially flat toward the second object side 102, an aperture stop 103, and a convex surface facing away from the second object 102. A substantially planoconvex positive lens L321, a substantially planoconvex aspherical positive lens L322 with the convex surface facing away from the second object 102, and a meniscus aspherical surface with the concave surface facing the second object side. Positive lens L323, flat The a positive lens L324 plano-convex toward the second object 102 side. Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3.

  Also in this embodiment, a so-called immersion optical system configuration is adopted in which the gap between the final lens L324 and the second object 102 is filled with a liquid.

  In this embodiment, the projection magnification is 1/6, the reference wavelength is 193 nm, and quartz and fluorite are used as the glass material. Further, the numerical aperture on the image side is NA = 1.30, and the distance between the object images (the first object surface to the second object surface) is L = 1704.76 mm. In addition, aberration correction is performed in an image height range of approximately 2.75 to 13.75 mm, and a rectangular exposure area of at least 17 mm in the length direction and about 8 mm in width can be secured. The aperture stop 103 is disposed between L320 and L321.

  Further, a lateral aberration diagram of this example is shown in FIG. Here, the drawing described as Y = 2.75 shows a lateral aberration diagram of light from the off-axis region where the image height of the second object is 2.75 mm, and Y = 13.75 is the first figure. The lateral aberration figure of the light from the off-axis area | region whose image height in the object of 2 is 13.75 mm is shown. FIG. 15 shows the reference wavelengths of 193.0 nm and ± 0.2 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  The specific lens configuration of Example 6 is shown in FIG. The first imaging optical system in the figure includes a refractive lens group L1A having a positive refractive power and a refractive lens group L1B having a positive refractive power in order from the first object side. The refractive lens unit L1A having a positive refractive power includes a negative lens L111 having a substantially plano-concave shape with a concave surface facing the first object side along the light traveling direction from the first object 101 side, the first object side. A substantially plano-convex aspherical positive lens L112 having a convex surface facing the surface, a biconvex positive lens L113, and two substantially plano-convex positive lenses L114 and L115 having a convex surface facing the first object side. ing. The refractive lens unit L1B having positive refractive power includes a substantially meniscus negative lens L116 having a concave surface facing away from the first object side, and a meniscus negative lens having a concave surface facing the first object side. L117, a meniscus positive lens L118 having a concave surface facing the first object side, a biconvex positive lens L119, and a substantially plano-convex aspherical positive lens L120 having a convex surface facing the first object side Become.

  The second imaging optical system Gr2 includes a reciprocating optical system portion L2 having a negative refractive power and a concave mirror M1. Then, along the traveling direction of the light from the first imaging optical system Gr1, a substantially plano-concave negative lens L211 having a concave surface directed to the first object side, and a meniscus shape having a concave surface directed to the first object side. An aspherical concave lens L212 and a concave mirror M1 with the concave surface facing the first object side. After the light beam from the first imaging optical system Gr1 is incident on the reciprocating optical system part L2, is reflected by the concave mirror M1, and is incident on the reciprocating optical system part L2 again. The light beam is also bent by being bent 90 degrees to form a second intermediate image IMG2. The deflecting / reflecting member FM1 is disposed between the second and third imaging optical systems, but desirably is disposed between the second intermediate image IMG2 and the reciprocating optical system portion L2 as in the present embodiment. good. The third imaging optical system Gr3 includes a refractive lens group L3A having a positive refractive power and a refractive lens group L3B having a positive refractive power. The refractive lens group L3A having a positive refractive power includes a substantially plano-convex positive lens L311 having a substantially flat surface directed toward the second intermediate image IMG2 along the traveling direction of light from the second imaging optical system Gr2. It consists of a substantially plano-convex positive lens L312 with a substantially flat surface facing the second intermediate image IMG2, and a substantially plano-convex L313 with a substantially flat surface facing the second deflecting / reflecting member FM2. The refractive lens unit L3B having a positive refractive power includes a meniscus positive lens L314 having a concave surface directed toward the second object 102, a biconcave aspheric negative lens L315, and a convex surface opposite to the second object side. Two meniscus positive lenses L316 and L317 facing toward the side, a substantially plano-convex aspherical positive lens L318 whose substantially plane faces toward the second object side 102, and a concave surface opposite to the second object side A negative meniscus lens L319 facing toward the surface, a substantially plano-convex aspherical positive lens L320 facing substantially flat toward the second object side 102, an aperture stop 103, and a convex surface facing away from the second object 102. A substantially plano-convex positive lens L321, meniscus aspherical positive lenses L322 and L323 having a convex surface facing away from the second object 102, and a plano-convex shape having a flat surface facing the second object 102. Positive lens L3 Consisting of 4. Further, the second deflecting / reflecting member FM2 is disposed between the refractive lens groups L3A and L3B in the third imaging optical system Gr3.

  Also in this embodiment, a so-called immersion optical system configuration is adopted in which the gap between the final lens L324 and the second object 102 is filled with a liquid.

  In this embodiment, the projection magnification is 1/8, the reference wavelength is 193 nm, and quartz or fluorite is used as the glass material. The numerical aperture on the image side is NA = 1.35, and the distance between the object images (the first object plane to the second object plane) is L = 1753.2 mm. In addition, aberration correction is performed in the image height range of approximately 2.06 to 10.3 mm, and a rectangular exposure area of at least 13 mm in the length direction and about 5.9 mm in width can be secured. The aperture stop 103 is disposed between L320 and L321.

  Further, FIG. 16 shows a lateral aberration diagram of this example. Here, the drawing described as Y = 2.06 shows a lateral aberration diagram of light from the off-axis region where the image height of the second object is 2.06 mm, and Y = 10.3 is the first figure. The lateral aberration figure of the light from the off-axis area | region whose image height in the object of 2 is 10.3 mm is shown. FIG. 16 shows the reference wavelengths of 193.0 nm and ± 0.2 pm, and it can be seen that monochromaticity and chromatic aberration are corrected well.

  The following [Tables 5 and 6] show the configuration specifications of the numerical embodiment of Example 3 above, and [Tables 7 and 8] show the configuration specifications of the numerical embodiment of Example 4 above [Tables 9 and 10]. ] Shows the configuration specifications of the numerical embodiment of the fifth embodiment, and [Tables 11 and 12] show the configuration specifications of the numerical embodiment of the sixth embodiment in correspondence with the respective embodiments. The explanation of the symbols in the table is the same as (Tables 1 and 2), and is omitted here.

  The lens glass materials SiO2, CaF2 and liquid water (water, preferably pure water) have refractive indexes of 1.5609, 1.5018, and 1.437, respectively, with respect to the reference wavelength λ = 193.0 nm. Further, the refractive indexes of the wavelengths of +0.2 pm and −0.2 pm with respect to the reference wavelength are 1.56089968 and 1.56090031, respectively, in the case of SiO2, and 1.50179980, 1.50180019, respectively, in the case of CaF2. In the case of water, they are 1.436699576 and 1.437000424, respectively.

  Examples 1 to 6 described so far may be used in combination within a consistent range. That is, as described above, it is within the scope of the present embodiment to use any combination of conditional expressions. In addition, the numerical value corresponding to each conditional expression is as having shown in the table | surface which shows each Examples 1-6.

  The seventh embodiment is an example of an exposure apparatus to which the (catadioptric) projection optical system described in the first to sixth embodiments is applied.

  Hereinafter, an exemplary exposure apparatus 200 to which the projection optical system 230 of the present invention is applied will be described with reference to FIG. Here, FIG. 17 is a schematic block sectional view showing an exemplary embodiment of the exposure apparatus 200 as one aspect of the present invention, and therefore the projection optical system 230 is also shown in a simplified manner. Is a projection optical system according to the first to sixth embodiments. As shown in FIG. 17, the exposure apparatus 200 illuminates a mask (first object) 220 on which a circuit pattern is formed, and diffracted light generated from the illuminated mask pattern on a plate (second object). , A wafer) 240 and a stage 245 that supports the plate 240.

  The exposure apparatus 200 is a projection exposure apparatus that exposes a circuit pattern formed on the mask 220 to the plate 240 by, for example, a step-and-scan method or a step-and-repeat method. Such an exposure apparatus is suitable for a lithography process of sub-micron or quarter micron or less, and in the present embodiment, a step-and-scan type exposure apparatus (also referred to as “scanner”) will be described as an example. Here, the “step and scan method” means that the wafer is continuously scanned (scanned) with respect to the mask to expose the mask pattern onto the wafer, and the wafer is stepped after the exposure of one shot is completed. The exposure method moves to the next exposure area. The “step-and-repeat method” is an exposure method in which the wafer is stepped and moved to the exposure area of the next shot for every batch exposure of the wafer.

  The illumination device 210 illuminates the mask 220 on which a transfer circuit pattern is formed, and includes a light source unit 212 and an illumination optical system 214.

For the light source unit 212, for example, an F ₂ laser having a wavelength of about 157 nm, an ArF excimer laser having a wavelength of about 193 nm, or the like can be used as the light source. However, the type of the light source is not limited to the excimer laser. A 248 nm KrF excimer laser or YAG laser may be used, and the number of light sources is not limited. Further, an EUV light source or the like may be used. For example, if two solid-state lasers (which can be gas lasers) that operate independently are used, there is no mutual coherence between the solid-state lasers, and speckle caused by the coherence is considerably reduced. Further, the optical system may be swung linearly or rotationally to reduce speckle. When a laser is used for the light source unit 212, a light beam shaping optical system that shapes a parallel light beam from the laser light source into a desired beam shape and an incoherent optical system that makes a coherent laser beam incoherent are used. Is preferred. The light source usable in the light source unit 212 is not limited to a laser, and one or a plurality of lamps such as a mercury lamp and a xenon lamp can be used.

  The illumination optical system 214 is an optical system that illuminates the mask 220, and includes a lens, a mirror, an optical integrator, a stop, and the like. For example, a condenser lens, a fly-eye lens, an aperture stop, a condenser lens, a slit, and an imaging optical system are arranged in this order. The illumination optical system 214 can be used regardless of on-axis light or off-axis light. The optical integrator includes an integrator configured by stacking a fly-eye lens and two sets of cylindrical lens array (or lenticular lens) plates, and may be replaced by an optical rod or a diffractive element.

  The mask 200 is made of, for example, quartz, on which a circuit pattern (or image) to be transferred is formed, and is supported and driven by a mask stage (not shown). Diffracted light emitted from the mask 220 passes through the projection optical system 230 and is projected onto the plate 240. The mask 220 and the plate 240 are in an optically conjugate relationship. Since the exposure apparatus 200 of this embodiment is a scanner, the pattern of the mask 220 is transferred onto the plate 240 by scanning the mask 220 and the plate 240 at a speed ratio of the reduction ratio. In the case of a step-and-repeat type exposure apparatus (also called “stepper”), exposure is performed with the mask 220 and the plate 240 being stationary.

  The projection optical system 230 includes an optical system including only a plurality of lens elements, an optical system (catadioptric optical system) having a plurality of lens elements and at least one concave mirror, a plurality of lens elements, and at least one kinoform. An optical system having a diffractive optical element such as an all-mirror optical system can be used. When correction of chromatic aberration is required, a plurality of lens elements made of glass materials having different dispersion values (Abbe values) can be used, or the diffractive optical element can be configured to generate dispersion in the opposite direction to the lens element. To do.

  The plate 240 is an object to be processed such as a wafer or a liquid crystal substrate, and is coated with a photoresist. The photoresist coating process includes a pretreatment, an adhesion improver coating process, a photoresist coating process, and a prebaking process. Pretreatment includes washing, drying and the like. The adhesion improver coating process is a surface modification process for improving the adhesion between the photoresist and the base (that is, a hydrophobic process by application of a surfactant), and an organic film such as HMDS (Hexmethyl-disilazane) is used. Coat or steam. Pre-baking is a baking (baking) step, but is softer than that after development, and removes the solvent.

  The stage 245 supports the plate 240. Since any structure known in the art can be applied to the stage 245, a detailed description of the structure and operation is omitted here. For example, the stage 245 can move the plate in the XY directions using a linear motor. The mask 220 and the plate 240 are synchronously scanned, for example, and the positions of the stage 245 and the mask stage (not shown) are monitored by a laser interferometer, for example, and both are driven at a constant speed ratio. The stage 245 is provided on a stage surface plate supported on a floor or the like via a damper, for example, and the mask stage and the projection optical system 230 are provided with a damper on a base frame placed on the floor or the like, for example. It is provided on a lens barrel surface plate (not shown) that is supported via the cable.

  In the exposure, the light beam emitted from the light source unit 212 illuminates the mask 220 by, for example, Koehler illumination by the illumination optical system 214. Light that passes through the mask 220 and reflects the mask pattern is imaged on the plate 240 by the projection optical system 230.

  Next, as an eighth embodiment, referring to FIGS. 18 and 19, an embodiment of a device manufacturing method using the above-described exposure apparatus (exposure apparatus having the projection optical system described in the first to sixth embodiments) is used. explain.

  FIG. 18 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, and the like). In the present embodiment, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in step 4. The assembly process (dicing, bonding), packaging process (chip encapsulation), and the like are performed. Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

  FIG. 19 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 1 to expose a circuit pattern on the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before. Thus, the device manufacturing method using the above-described exposure apparatus and the resulting device also constitute one aspect of the present invention.

It is a schematic block diagram of the catadioptric projection optical system of this invention. It is a schematic block diagram of the catadioptric projection optical system of another embodiment of this invention. 1 is an optical path diagram illustrating a catadioptric projection optical system according to a first embodiment of the present invention. It is an optical path diagram which shows the catadioptric projection optical system of the 2nd example of the present invention. It is an aberration diagram of the first embodiment of the present invention. It is an aberration diagram of the second embodiment of the present invention. It is a schematic block diagram of the catadioptric projection optical system of another embodiment of this invention. 1 is a schematic block cross-sectional view showing an exemplary embodiment of a projection optical system as one aspect of the present invention. It is an optical path diagram which shows the catadioptric projection optical system of the 3rd example of the present invention. It is an optical path diagram which shows the catadioptric projection optical system of 4th Example of this invention. It is an optical path diagram which shows the catadioptric projection optical system of the 5th example of the present invention. It is an optical path figure which shows the catadioptric projection optical system of 6th Example of this invention. It is an aberration diagram of the third embodiment of the present invention. It is an aberration diagram of the fourth embodiment of the present invention. It is an aberration diagram of the fifth example of the present invention. It is an aberration diagram of the sixth embodiment of the present invention. 1 is a schematic block sectional view showing an exemplary embodiment of an exposure apparatus as one aspect of the present invention. It is a flowchart for demonstrating manufacture of devices (semiconductor chips, such as IC and LSI, LCD, CCD, etc.). FIG. 19 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 18. FIG.

Explanation of symbols

101 First object plane 102 Second object plane 103 Aperture stop Gr1 First imaging optical system Gr2 Second imaging optical system Gr3 Third imaging optical system IMG1 First intermediate image IMG2 Second intermediate image FM1 First Deflection and reflection member FM2 Second deflection and reflection member L2 Reciprocating optical system portion of second imaging optical system L Distance between object images (distance measured along AX1 of first object and second object)
AX1, AX2, AX3 Optical axis

Claims (20)

Along the optical path from the first object side,
A first imaging optical system having at least one lens and forming a first intermediate image of the first object;
A second imaging optical system having at least one lens and at least one concave mirror and forming a second intermediate image of the first object;
A third imaging optical system having at least one lens and forming an image of the first object on the second object; and forming an image of the first object on the second object. A projection optical system for imaging,
Having at least one deflecting reflecting member;
When the paraxial magnification of the first imaging optical system is β1, and the paraxial magnification of the second imaging optical system is β2,
0.70 <| β1 · β2 | <3.0
Projection optical system characterized by satisfying A projection optical system that forms an image of the first object on a second object after forming an intermediate image of the first object twice;
Along the optical path from the first object side,
A first imaging optical system having at least one lens;
In order from the first object side, a second imaging optical system having a first deflecting / reflecting member, a refractive lens group, and a concave mirror,
A third imaging optical system having at least one lens and a second deflecting / reflecting member having a normal that is substantially 90 degrees with respect to the normal of the first deflecting / reflecting member;
The first object and the concave mirror are arranged opposite to each other;
The light beam from the first imaging optical system is reflected in the order of the concave mirror and the first deflecting / reflecting member and guided to the third imaging optical system, and the first deflecting / reflecting member causes the first deflecting / reflecting member to A projection optical system characterized in that a light beam from a deflecting reflecting member is deflected and guided to the second object. A projection optical system that forms an image of the first object on a second object after forming an intermediate image of the first object twice;
Along the optical path from the first object side,
A first imaging optical system having at least one lens;
In order from the first object side, a second imaging optical system having a first deflecting / reflecting member, a refractive lens group, and a concave mirror,
A third imaging optical system having at least one lens;
The first object and the concave mirror are arranged to face each other,
The deflecting / reflecting member is moved with respect to the optical axis of the second image-forming optical system so that the light beam from the first imaging optical system to the concave mirror and the light beam reflected by the first deflecting / reflecting member intersect each other. The projection optical system is arranged so as to form a predetermined angle. When the paraxial magnification of the first imaging optical system is β1, and the paraxial magnification of the second imaging optical system is β2,
0.70 <| β1 · β2 | <3.0
The projection optical system according to claim 2, wherein the projection optical system satisfies the following. 5. The projection optical system according to claim 1, wherein the following conditional expression is satisfied when a paraxial magnification of the first imaging optical system is β <b> 1.
0.70 <| β1 | <2.0 The projection optical system according to claim 1, wherein the following conditional expression is satisfied, where β2 is a paraxial magnification of the second imaging optical system.
0.70 <| β2 | <2.0 A projection optical system that projects an image of a first object onto a second object,
In order from the first object side, the image forming apparatus includes at least one lens, a first imaging optical system that forms a first intermediate image of the first object, at least one lens, and at least one concave mirror. And a second imaging optical system that forms a second intermediate image of the first object and at least one lens, and a third object that forms an image of the first object on the second object. An imaging optical system,
When the paraxial magnification of the first imaging optical system is β1, the paraxial magnification of the second imaging optical system is β2, and the numerical aperture on the first object side of the projection optical system is NAo,
3.5 <| β1 · β2 | / NAo <20
Projection optical system characterized by satisfying The projection optical system according to claim 7, wherein the following conditional expression is satisfied.
4.0 <| β1 · β2 | / NAo <10 The projection optical system according to claim 1, wherein the following conditional expression is satisfied, where NA is a numerical aperture on the second object side of the projection optical system.
1.1 <NA <1.6 When the Petzval sum of the first imaging optical system is P1, the Petzval sum of the second imaging optical system is P2, and the Petzval sum P3 of the third imaging optical system,
P1> 0, P2 <0, P3> 0
The projection optical system according to claim 1, wherein: The second imaging optical system has one concave mirror, the effective diameter of the one concave mirror is φM1, and the most off-axis principal ray emitted from the first object is incident on the concave mirror. When the height from the optical axis of one imaging optical system is hM1,
0 ≦ | hM1 / φM1 | <0.10
The projection optical system according to claim 1, wherein: The first deflecting / reflecting member that reflects the reflected light from the concave mirror of the second imaging optical system, and the reflected light from the first deflecting / reflecting member are disposed at an angle of approximately 90 degrees with the first deflecting / reflecting member. And a second deflecting / reflecting member for guiding the second object to the second object side,
The distance between the optical axis of the first imaging optical system and the optical axis of the optical system between the second deflecting / reflecting member and the second object is Y, and the maximum effective diameter in the second imaging optical system is φGr2_max, when the maximum effective diameter in the optical system between the second deflecting and reflecting member and the second object is φL3B_max,
0.2 <(φGr2_max + φL3B_max) / (2Y) <0.9
The projection optical system according to claim 1, wherein: A first deflecting / reflecting member that reflects reflected light from the concave mirror of the second imaging optical system;
When the angle between the principal ray from the off-axis of the first object and the normal line of the reflecting surface of the first deflecting reflecting member is θp,
20 ° <θp <45 °
The projection optical system according to claim 1, wherein: The projection optical system according to claim 13, wherein the following conditional expression is satisfied.
30 ° <θp <44 °   The projection optical system according to claim 1, wherein the concave mirror is disposed to face the first object.   16. The projection optical system according to claim 1, wherein two deflection reflection members are arranged in an optical path from the concave mirror of the second imaging optical system to the second object plane. system.   17. The projection optical system according to claim 16, wherein the normal line of each of the reflecting surfaces of the two deflecting reflection members forms an angle of substantially 90 degrees with respect to the normal line to each other.   The projection optical system according to claim 1, wherein the deflecting reflecting member is a reflecting mirror.   An illumination optical system that illuminates the first object with light from a light source, and a projection optical system according to any one of claims 1 to 18 that projects light from the first object onto the second object. An exposure apparatus comprising: 20. A device manufacturing method comprising: an exposure step of exposing the second object using the exposure apparatus according to claim 19; and a development step of developing the exposed second object.

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