JP2005504337A - Catadioptric reduction lens - Google Patents

Abstract

A combination of a very high image edge numerical aperture and a useful configuration allows for full achromaticity.
A catadioptric projection lens for imaging a pattern disposed on an object plane onto an image plane preferably includes a catadioptric first lens section having a concave mirror and a beam splitting surface while forming a real intermediate image. A physical beam splitter is preferably included between the object plane and the image plane, together with a second lens section that is preferably refractive and follows the beam splitter. A positive refractive power is placed in the optical near field of the object plane, which is placed at a working distance from the first optical surface of the projection lens. The beam splitter is at a low outer edge ray height, which constitutes a projection lens that is well corrected for longitudinal chromatic aberration while employing a small amount of material, especially the material needed to manufacture the beam splitter. Making it possible.
[Selection] Figure 1

Description

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【図面の簡単な説明】
【０１１５】
【図１】本発明の第１実施例による複数のレンズを示す断面図。
【図２】本発明の第２実施例による複数のレンズを示す断面図。
【図３】本発明の第３実施例による複数のレンズを示す断面図。
【図４】本発明の第４実施例による複数のレンズを示す断面図。
【図５】本発明の第５実施例による複数のレンズを示す断面図。
【図６】本発明の第６実施例による複数のレンズを示す断面図。
【図７】本発明の第７実施例による複数のレンズを示す断面図。
【図８】図７に描かれたビームディフレクタの近傍を示す詳細概念図。
【図９】本発明の第８実施例による複数のレンズを示す断面図。
【図１０】本発明の第９実施例による複数のレンズを示す断面図。
【符号の説明】
【０１１６】
１５ 第１セグメント
１６ 第２セグメント
１９ 偏向角度
１００ 反射屈折縮小レンズ
１０１ 物平面
１０２ 中間像
１０３ 像面
１０４ 反射屈折第１レンズセクション
１０５ 縮小第２レンズセクション
１０６ ビームスプリッタ
１０７ ビームスプリット表面
１０８ ミラー群
１０９ イメージング凹面鏡
１１０ 平板偏向ミラー
１１１ 入射板
１１３、１１４ 負レンズ
１１２、１１５ 正レンズ
１２３ 正メニスカスレンズ
１２４ 負レンズ
２００ 縮小レンズ
２０６ ビームスプリッタ
２０７ ビームスプリット表面
２０８ ミラー群
２０９ 凹面鏡
２１０ ビーム偏向ミラー
２１１ 入射エレメント
２１２ メニスカスレンズ【Technical field】
[0001]
The present invention relates to a catadioptric projection lens for imaging a pattern arranged on an object plane on an image plane.
[Background]
[0002]
This type of projection lens is used in projection exposure systems, particularly wafer scanners and wafer steppers, and is used for semiconductor devices and other types of microdevices, which can be used for patterning on photomasks and reticles. "Or" reticle ", but serves to project on a scaled scale with ultra-high resolution onto an object having a photosensitive coating.
[0003]
In order to produce a finer structure, it is desirable to increase the image edge numerical aperture (NA) of the projection lens and to use ultraviolet light having a shorter wavelength, preferably shorter than about 260 nm.
[0004]
However, materials that are sufficiently transparent in the wavelength range that can be used to produce the required optical elements, particularly crystalline quartz such as synthetic quartz glass, calcium fluoride, lithium strontium aluminum fluoride, and lithium fluoride. There is almost no monster. Because the Abbe numbers of these materials available are quite close to each other, it is difficult to provide a purely refractive system that is sufficiently well color corrected (corrected for chromatic aberration). This problem can be solved by using a purely refractive system, but producing such a mirror system involves considerable expense and effort.
[0005]
With respect to the aforementioned problems, catadioptric systems that combine refractive and reflective elements, particularly lenses and mirrors, are typically used to construct high resolution projection lenses of the aforementioned type.
[0006]
Whenever it involves imaging a reflective surface, it is beneficial to use a beam deflector if an image without obscuration and vignetting is to be achieved. Both systems with geometric beam splitters and systems with physical beam splitters are known. A system with geometric beam splitting achieved with the help of a pair of beam deflecting mirrors is disclosed in European Patent 0 898 434 corresponding to US patent application 09/364382. While systems with geometric beam splitting have the disadvantage that they are necessarily off-axis systems due to geometric beam splitting, using physical beam splitters can reduce the on-axis system. Make it configurable.
[0007]
A system with a physical beam splitter is known from EP 0475020 corresponding to US Pat. No. 5,052,763. The system has at least one catadioptric entrance system and a refractive exit system. The mask to be imaged is placed directly on a beam splitter configured in the form of a beam splitter cube (BSC) and deflects part of the light reflected by the catadioptric system into the refractive system. However, placing the object to be imaged directly on the beam splitter limits the opportunity to correct the entire system. Furthermore, the object end of this system is non-telecentric.
[0008]
Another catadioptric system with a physical beam splitter and an intermediate image is known from US Pat. No. 5,694,241, in which a lens group with positive refractive power is arranged between the object plane and the beam splitter. This is far from the object plane.
[0009]
In the catadioptric lens having no intermediate image, the first lens group is provided between the object plane and the physical beam splitter, the second lens group is provided between the physical beam splitter and the concave mirror, and the third lens. It is known from European patent application 0350955 corresponding to US patent application 4,953,960 that the group is provided between the physical beam splitter and the image plane. The lens group placed between the beam splitter and the concave mirror is intended to correct the low-order coma and spherical aberration of the concave mirror along with the Gaussian error, where a low negative refractive power is the longitudinal axis of the refractive group. It is sufficient to compensate for chromatic aberration.
[0010]
The catadioptric projection lens has a physical beam splitter, does not have an intermediate image, allows a high numerical aperture at the image end of at least 0.5, has both an advantageous configuration and low sensitivity to alignment errors, German patent No. 4203464, which corresponds to US patent application 5,402,267. This system is greatly characterized in that no lens group is disposed between the concave mirror and the beam splitter, and the concave mirror has an intensity reduction effect, that is, an image reduction magnification of intensity. Longitudinal chromatic aberration (CHL) may first be corrected by using a highly convergent beam of a beam splitter, resulting in a total achromaticity of longitudinal chromatic aberration. The beam in front of the concave mirror, ie through its first pass of the beam splitter, is almost or substantially collimated, while the beam following the concave mirror, ie through its second pass of the beam splitter, is usually highly focused. ing. The system stop is preferably located at the concave mirror and is defined by its perimeter. This stop is defined at the surface of the beam splitter facing the concave mirror or by inserting a stop between the concave mirror and the beam splitter. Another advantage provided by a highly focused beam following reflection at the concave mirror is that a slight refractive power must be provided following the beam splitter, resulting in a relatively small beam height in the vicinity. Means that the opposite effect on chromatic aberration due to the large beam height in the vicinity can be avoided.
[0011]
The advantage provided by this type of lens is counteracted by the disadvantages, i.e. the light incident on the beam splitting surface converges in a second pass, especially following reflection at the concave mirror, which occurs at that surface The range of incident angles is very wide, which places strict requirements on the quality of the beam split coating. The sharp convergence of the beam following reflection at the concave mirror means that there is little space available for the lens following the beam splitter, and there is little means to correct the aberrations that remain available. doing. Increasing the image edge numerical aperture further requires the use of a larger beam splitter cube and shifts the image plane to the beam splitter. Such a projection lens is also recognized as “aperture restriction”. Another of these disadvantages requires that they use relatively large beam splitters, which are expensive due to the limited availability of materials suitable for their manufacture.
[0012]
Basically the same problem arises in the case of projection lenses that are similarly configured and have similar beam paths, which are described in German patent application 4203464. In the following, for example, those projection lenses depicted in U.S. Patent Applications 6,118,596, 6,108,140, and 6,101,047 are included. A large angle of incidence on the beam splitter surface occurs in systems such as those depicted in US Pat. Nos. 5,808,805, 5,999,333, or 5,861,997, where the intermediate image is Formed in the vicinity of their beam splitting surfaces.
[0013]
A catadioptric projection lens has a physical beam splitter, does not have an intermediate image, the beam is slightly diverging in its first path of the beam splitting coating, and in the second path of its coating, i.e. at the concave mirror Following the reflection, it is collimated, which is intended to make it possible to avoid image quality degradation since the reflection of the beam splitting coating is dependent on the angle of incidence, and US patent application 5,771,125. Known from the issue. The light reflected by this coating is collimated by maintaining the refractive power of the lens group that includes the concave mirror relatively low. However, in the case of the system depicted in European patent application 0602923 corresponding to US patent application 5,715,084, the beam splitting coating in the first path is collimated with the aim of collimating the light incident on the coating. A lens is placed in front of the physical beam splitter. The beam converges following reflection by the concave mirror. Such a system requires the use of a large beam splitter.
[0014]
In the case of a catadioptric projection system with a physical beam splitter and no intermediate image, German patent application 4 417 489 corresponding to US patent application 5,742,436 describes at least one condenser lens, ie the beam at the object end. Scattering lens group having a positive refractive power for collimating the beam incident on the splitting coating, in order to minimize the angle of incidence on the beam splitting coating, in front of the physical beam splitter, and having a negative lens In the catadioptric lens section, following the physical beam splitter, ie between the beam splitter and the concave mirror, is proposed to compensate for the effect of the condenser lens in front of the beam splitter and to correct longitudinal chromatic aberration doing. Under this design, the beam is substantially collimated in both propagation directions through the beam splitter cube. The system stop usually follows the beam splitter cube in the light train. Since the beam is substantially collimated in both propagation directions through the beam splitter cube, problems due to the wide angle of incidence are avoided. Another advantage of the collimated beam in the second pass following reflection at this concave mirror is that there is sufficient space available on the side of the image of the beam splitter that includes means for correcting aberrations. The disadvantage of the arrangement with respect to German patent application 4174489 is that its overcorrected catadioptric lens section cannot adequately correct longitudinal chromatic aberration (CHL). This arrangement requires the use of a relatively large beam splitter, which is disadvantageous because of the limited availability of materials suitable for its manufacture.
[0015]
EP 1102100 describes a catadioptric reduction lens that corresponds to US patent application 09/711256, but differs from the configuration depicted in DE 4417489, in particular it sufficiently corrects longitudinal chromatic aberration. Making it possible. The system includes a first lens section having a positive refractive power, a physical beam splitter having a beam splitting surface, a second lens section disposed between the physical beam splitter and the concave lens, the beam splitter and its image plane. The third lens section is disposed between the object plane and the image plane in that order. At least two lenses having negative refractive power are repositioned in the second lens section. The high negative power concentration provides the advantage of sufficiently correcting longitudinal chromatic aberration, especially near the concave mirror, both between the object plane and the first lens section and between the third lens section and the image plane. Allows the construction of a system with working distance, which allows its application to microlithography. This system makes it possible to provide a highly collimated beam for the purpose of limiting the angle of incidence on the beam splitting surface through the beam splitting surface in both propagation directions in the vicinity of the beam splitting surface, and This makes it possible to largely avoid the aforementioned disadvantages in which the incident angle varies widely. This patent describes an embodiment with an intermediate image and is associated with a numerical aperture NA that rises to about NA = 0.7. The disadvantage associated therewith is that a relatively large amount of material is lacking in a suitable amount and is needed to produce a beam splitter.
[0016]
In particular, US Pat. No. 6,377,338 shows a system having a physical beam splitter that is inherited from a crystalline fluoride source.
[0017]
In the case of the system with the aforementioned physical beam splitter, its respective beam splitting surface is inclined at an angle of 45 ° with respect to the segment of the optical axis perpendicular to the image plane. Any deflection or bending mirror can be present, particularly in the second lens section, but is tilted at an angle of 45 ° with respect to the optical axis. For the purpose of folding the optical axis at the correct angle, this makes it possible to achieve an orthogonal or parallel arrangement of the object plane and the image plane, both preferred, but the latter arrangement is particularly advantageous for scanner operation.
[Patent Document 1]
US patent application 09/364382
[Patent Document 2]
European Patent 0989434
[Patent Document 3]
US Pat. No. 5,052,763
[Patent Document 4]
European Patent No. 0475020
[Patent Document 5]
US Pat. No. 5,694,241
[Patent Document 6]
US Patent Application No. 4,953,960
[Patent Document 7]
European Patent Application 0350955
[Patent Document 8]
German patent application 4203464
[Patent Document 9]
US Patent Application No. 5,402,267
[Patent Document 10]
US Patent Application No. 6,118,596
[Patent Document 11]
US Patent Application No. 6,108,140
[Patent Document 12]
US Patent Application No. 6,101,047
[Patent Document 13]
US Pat. No. 5,808,805
[Patent Document 14]
US Pat. No. 5,999,333
[Patent Document 15]
US Pat. No. 5,861,997
[Patent Document 16]
US Patent Application No. 5,771,125
[Patent Document 17]
US Patent Application No. 5,715,084
[Patent Document 18]
European Patent Application No. 0602923
[Patent Document 19]
US Patent Application No. 5,742,436
[Patent Document 20]
German patent application 4174489
[Patent Document 21]
European patent 1102100
[Patent Document 22]
US patent application 09/711256
[Patent Document 23]
German patent 4417489
[Patent Document 24]
US Pat. No. 6,377,338
DISCLOSURE OF THE INVENTION
[Problems to be solved by the invention]
[0018]
One object of the present invention is to provide a catadioptric lens having a physical beam splitter that avoids the disadvantages of the prior art. In particular, it can be fully achromatic in combination with a very high image edge numerical aperture and beneficial construction. This object should be achieved using a small amount of material, in particular to manufacture a beam splitter and components located in the vicinity of the beam splitter. An advantageous configuration should preferably be obtained, especially in the vicinity of the object plane.
[Means for Solving the Problems]
[0019]
As a solution to these and other objects, the present invention provides a catadioptric projection lens having the features set forth in claim 1. Advantageous embodiments thereof are set forth in the dependent claims. The wording of all claims forms part of this specification and is embodied by reference to the content of this specification.
【The invention's effect】
[0020]
All colors can be erased in combination with a very high image edge numerical aperture and useful construction.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021]
The catadioptric projection lens according to the present invention is configured to image a pattern arranged in the object plane on the image plane, and includes a catadioptric first lens section comprising a concave mirror and a beam split coating between the object plane and the image plane. Having a physical beam splitter. The second lens section is preferably configured to be a refractive system and is placed following the beam splitter.
[0022]
According to one aspect of the invention, the object plane is located at a working distance from the first optical surface of the projection lens. The positive refractive power is placed in the optical near field of the object plane. The beam splitter is arranged in a zone where the outer edge ray height is low. At least one real intermediate image is preferably formed.
[0023]
The object plane of the projection lens or the unobstructed (free) working distance between the reticle surface and the first optical component should preferably exceed 30 mm, in particular it may exceed 35 mm and may damage the projection lens. It is possible in a simple manner to handle the reticle without any problems and to keep the reticle area and the entrance surface of the projection lens gas-assisted cleaning or cleanliness.
[0024]
The positive refractive power present in the optical near field of the object plane allows a telecentric configuration of the object end of the projection lens, which is particularly beneficial with respect to defocus errors. Here, the “object near-field optical near field” is a zone where the beam outer edge ray height is particularly less than about 30% of the outer edge ray height in the vicinity of the concave mirror.
[0025]
Placing the beam splitter in the vicinity of the lower outer edge ray height makes it possible to construct a projection lens in accordance with the present invention having a very small beam splitter compared to the prior art. This is particularly convenient for projection lenses intended for use at operating wavelengths shorter than about 260 nm, in particular operating wavelengths of 193 nm or 157 nm or shorter. Transparent materials, especially crystalline fluorides such as calcium fluoride, magnesium fluoride, lithium calcium aluminum fluoride, lithium strontium aluminum fluoride, lithium fluoride, or barium fluoride, are for use at operating wavelengths in this range. Can be used to manufacture the optical components of any of the above, none of which can be manufactured with the high purity and uniformity required by large solid blocks, but only with currently available technology Can be manufactured in such a block, which is limited in practice by the availability of a sufficiently large chunk of material to perform an optical configuration using this material. This applies in particular to materials used to manufacture physical beam splitters, which are often configured in the form of beam splitter cubes (BSC) or other solid blocks of material. A configuration in which means for using a small beam splitter is provided is thus very practical.
[0026]
The desired region or zone of low outer edge ray height for placing the beam splitter is the region where the beam split surface is orthogonal to the optical axis, which varies from about 20% to about 70% of the outer edge ray height at the concave mirror. Preferably characterized by projection onto a plane perpendicular to the optical axis perpendicular to the axis. The dimension of the beam splitter along the direction perpendicular to the optical axis can thus be kept below 70% or below 50% of the diameter of the concave mirror.
[0027]
It is particularly advantageous if the beam splitter is arranged in the vicinity of an intermediate image where a low beam height occurs. The beam splitter is preferably closer to the intermediate image than the object plane. It is beneficial if the intermediate image is outside the beam splitter in order to avoid overheating of the beam splitter material due to the high radiant energy density. In this manner, the beam splitter can be placed in a region where the outer edge ray height is low, where the outer edge ray height is preferably the outer edge ray height at the concave mirror for both passages of the beam splitter. Should be less than about 70%.
[0028]
According to another aspect of the invention, the beam splitting surface is arranged at an angle of inclination with respect to the segment of the optical axis that runs perpendicular to the object plane different from 45 °, where there is a difference between the angle of inclination and 45 °. Should preferably exceed the maximum difference that would otherwise occur due to machine tolerances. In particular, the absolute value of the difference between the tilt angle and 45 ° may range from about 1 ° to about 10 °. The angle at which the optical axis is bent at a beam split surface tilted at such an angle is thus substantially different from a right angle, which is a new degree of freedom when designing a projection lens of the type described above. In particular, the mask placed in the object plane must be adapted at the reticle stage for holding in the vicinity of the object plane and for transport if necessary. Tilting the beam splitting surface in that manner allows the angle of incidence on the beam splitting surface to be shifted to the extent that it is readily manufactured and an optically effective beam splitter coating is available.
[0029]
This particular tilted orientation of the beam splitter surface is independent of other properties of the invention, other beam splitters than those specifically described in this patent application, such as systems having or lacking intermediate images, object edges This is useful for all projection lenses that have a system with or without a working distance and / or a system with a refractive power distribution.
[0030]
This tilt angle is preferably such that the deflection angle included between the optical axis segment orthogonal to the object plane and the optical axis segment extending from the beam splitter to the second lens section is greater than 90 °, The angle may then range from about 92 ° to about 110 °. This moves the physical beam splitter much closer to the object plane and keeps it relatively small, while at the same time the lens side arm supporting the concave mirror physically enters the space that fits the device for handling the mask. Making it possible to avoid.
[0031]
Projection lenses according to the present invention may be designed to have various bends in their beam path, where at least one deflection mirror is present before or after the first transmission optical component of the second lens section. It may be provided that it is assigned to a lens section. In the case of a beam splitter surface that is tilted at an angle different from 45 °, the deflection mirror should be tilted at an inclination angle with respect to the optical axis different from 45 °, where an inclination angle greater than 45 °, for example 46 °. Both tilt angles in the range from 55 to 55 and tilt angles less than 45 °, for example in the range from 35 ° to 44 °, are feasible. It is particularly beneficial if the tilt angle of the deflecting mirror is adjusted to match the tilt angle of the beam splitting surface so that the image plane is parallel or perpendicular to the object plane, where parallel placement is used for scanner operation. preferable.
[0032]
At least one lens of another type of optical component may be disposed between the beam splitting surface and a deflection mirror disposed in the second lens section. The space between the beam splitting surface and the deflection mirror followed by the optical train can be kept without optical components, but this allows the deflection mirror to be moved in the immediate vicinity of the beam splitting surface, which Can be used to minimize the lateral offset of the object plane. Furthermore, many projection lenses have a tilted segment of the optical axis that follows the beam splitting surface, i.e. neither vertical nor horizontal. The lens placed along that segment must be tilted in this way, i.e. its lens axis must be tilted. Avoiding such tilted lenses facilitates the design of their mounting and simplifies the alignment of such projection lenses.
[0033]
Several types of projection lenses of the present invention are characterized by imaging a pattern in which they are arranged in the object plane onto an image plane, forming at least one real intermediate image, where preferably Exactly one real intermediate image is formed. A projection lens having at least one intermediate image has at least one additional field plane in addition to its object plane and image plane, and at least one conjugate aperture in addition to its system stop, It means that many degrees of freedom are available for correcting imaging errors, for example, embodying a corrected aspheric surface with its optical components. This intermediate image is preferably freely accessible, for example because the field stop can be embodied in its vicinity. In the case of a freely accessible intermediate image, there is no optical material in the associated intermediate image plane, so material problems due to high radiant energy are largely eliminated.
[0034]
In many embodiments, the intermediate image is in the refractive optical second lens section, and at least one lens of the second lens section, in particular at least one positive lens, is located between the beam splitting surface and the intermediate image. Is done. This has a beneficial effect on the correction state of the intermediate image.
[0035]
According to another aspect of the invention, the object plane is located at a working distance from the first optical surface of the projection lens. There is substantially no positive refractive power in the space between the object plane and the beam splitter. The projection lens forms at least one intermediate image. The positive refracting power is placed in the object plane and / or in the optical near field of the intermediate image, and the beam splitter is placed in the region of low outer edge ray height.
[0036]
The advantages and beneficial dimensions of the freely accessible working area are described above. Placing the positive refractive power in the optical near field of the object plane supports reaching the vicinity of the beam splitter located in the vicinity of the intermediate image at a low outer edge ray height.
[0037]
Embodiments where the object end is non-telecentric are also feasible. This makes it possible, for example, to adapt them to an illumination system whose exit end is non-telecentric. This, as a result, makes it possible to change the magnification of the image of the mask positioned in the vicinity of the object plane with minimal axial adjustment.
[0038]
Since positive refractive power does not need to be provided in the space between the object plane and the beam splitter, a projection lens without an independent lens arranged between the object plane and the beam splitter is feasible, This keeps the design of this particular section very compact and allows a beam splitter with a small volume to be placed close to the object plane, where the edge beam height is low. The positive refracting power can be provided, for example, in the space between the beam splitter and the concave mirror, preferably in the optical near field of the object plane, in particular the edge ray height at least at one positive lens. Less than about 30% of the outer edge ray height at the concave mirror, which supports achieving object end telecentricity. Only a single positive lens should preferably be provided there.
[0039]
As an alternative or in addition thereto, positive refractive power can be placed following the beam splitter, but the outer edge ray height is low in that region. Here, the outer edge ray height can be made smaller than about 30% of the outer edge ray height of the concave mirror. In embodiments where the intermediate image is located well behind the beam splitter, the positive refractive power can be placed between the beam splitter and the intermediate image, preferably in the form of a single positive lens.
[0040]
In one embodiment, no positive lens is placed in either the space between the object plane and the beam splitter or the space between the beam splitter and the concave mirror. This makes it possible to adopt a simple design of the catadioptric lens section, which can be constructed without employing a positive lens.
[0041]
The imaging possibilities of the types of projection lenses described here reflect the polarization properties of their optical components, i.e. their light source, the optical material employed for their manufacture, the thin film of their coating, and their numerical aperture. It depends heavily on making full use. Calcium fluoride crystals have become available on the one hand, but have a more convenient stress birefringence coefficient (SBC) that drops to less than 1 nm / cm in addition to its better uniformity and better transmission . The value of the stress birefringence coefficient at a short wavelength, for example 157 nm, should not greatly exceed that value for the purpose that the quality of the resulting image is not limited there. With respect to stress birefringence, it is also beneficial, and it is also effective if the beam splitter block volume is kept as small as possible in order to keep the inherent birefringence interference contribution within acceptable limits. It is. Several versions of the projection lens according to the invention are optimized in this respect. For example, no refractive component such as a spherical or aspheric lens is placed between the object plane or the reticle and the beam splitter at all in order to allow the minimum distance between the object plane and its beam splitter to be maintained. Then it is beneficial. The planar parallel λ / 4 plate required and disposed therein has a negligible thickness and can, for example, be optically contacted on the entrance surface of the beam splitter. Access to the object plane supports a small beam splitter volume. It is also beneficial if the illumination system does not supply telecentric light and instead its chief ray is concentrated from the edge of the image field to the center of the beam splitter, for example in the case of a concentric entrance aperture . This makes it possible to both reduce the length of the prism upper end of the beam splitter block and reduce the axial offset between the object plane and the center of the image plane.
[0042]
In particular, in conjunction with the above means, it is beneficial if the material employed in the manufacture of the beam splitter is lithium fluoride or, if necessary, mixed lithium fluoride based crystals. In addition to its high transparency, the advantage of adopting lithium fluoride or similar material is that the absorption edge of UV light occurs at shorter wavelengths than, for example, calcium fluoride. The intrinsic birefringence coefficient is, for example, about half that of calcium fluoride, so that the polarization characteristics of the entire optical system are improved. Each of the aforementioned means is convenient when employed by itself, but combining all of them can, for example, reduce the intrinsic birefringence contribution to about 1/3 that of the known configuration. To.
[0043]
The advantages of placing the beam splitter in the region of low outer edge ray height and the preferred lower edge ray height are discussed above. It is particularly beneficial if the beam splitter is placed in the vicinity of the intermediate image, where a low edge ray height occurs. Preferably, the beam splitter is approximately midway between the object plane and the intermediate image and can be moved closer to the object plane if necessary. It is beneficial if the intermediate image is outside the beam splitter in order to avoid overheating of the beam splitter material due to high radiant energy density. It may be provided to arrange the beam splitter in a region with a low outer edge ray height, wherein the outer edge ray height is preferably approximately about the outer edge ray height at the concave mirror for both passages of the beam splitter. Should be less than 70%.
[0044]
Regardless of the design configuration in the vicinity of the beam splitter, it has been found beneficial to place a strong negative refractive power in the catadioptric lens section between the beam splitter and the concave mirror. This can be achieved by placing one or more negative lenses in the area, but it is preferred if at least two negative lenses are provided. In many embodiments, it is possible to concentrate a strong negative refractive power in that region by providing only a lens having a negative refractive power between the beam splitter and the concave mirror, that is, without a positive lens. Doing so makes it possible to reduce the number of lenses employed in that area. Less than 4 lenses, in particular less than 3 lenses, can be provided in order to save lens material and to simplify the production of projection lenses.
[0045]
In some embodiments, it is provided that no lens having a positive refractive power is provided in the vicinity of the concave lens, and the outer edge ray height within this neighborhood is the outer edge ray height at the concave lens. Preferably less than 70%. This allows for a more “loose” design of negative lenses that provide negative refractive power in that region, since they must also correct for the undercorrection introduced by the positive lens.
[0046]
The intensity of the negative power concentrated between the beam splitter and the concave mirror acts during both paths of the beam splitter, but should preferably be chosen to match the power of the other lens sections. The lens section positioned between the beam splitter and the concave mirror is overcorrected due to longitudinal chromatic aberration to substantially compensate for color undercorrection by other lens sections. At least 70% compensation, preferably more than 85%, is feasible for some embodiments.
[0047]
Positive refractive power can be provided in various ways within the optical near field of the object plane. Positive refractive power can be provided, for example, by placing a positive lens between the object plane and the beam splitter, but it has a small diameter in the region due to its accessibility to the object plane. sell. At most one positive lens is often provided in that region. Placing a positive refractive power in front of the beam splitter entrance surface can be used to reduce the divergence of rays coming from the object plane to some extent, where changes in the incident angle of the incident light are beam splitting. Because it is relatively small near the surface, it is a well collimated beam. In the preferred embodiment, to the point where the angle at the beam splitting surface between the outer edge ray and the optical axis is less than about 8 °, preferably less than 5 ° due to at least one direction of propagation through the beam splitting surface. The beam may be collimated for at least one direction of propagation through the beam splitting surface.
[0048]
In some embodiments, the isolated lens is not located between the object plane and the beam splitter. This keeps the design very compact in that particular section and allows the beam splitter to be placed close to its object plane, where the outer edge ray height is low. Positive refracting power is in the space between the beam splitter and the concave mirror, more particularly in the optical near field of the object plane, especially when the edge ray height at the at least one positive lens is the edge ray height at the concave mirror. It can be placed at a position less than about 30% of the height. Here, preferably only one positive lens is provided.
[0049]
Alternately or additionally, positive refracting power can be placed in the vicinity of the intermediate image, where the edge beam height is low. Within that vicinity, the outer edge ray height may be less than about 30% of the outer edge ray height at the concave mirror. For embodiments in which the intermediate image is located a sufficiently large distance behind the beam splitter, the positive refractive power is preferably between the beam splitter and the intermediate image, preferably in the form of a single positive lens. Can be arranged.
[0050]
In some embodiments, one or more aspheric surfaces are provided, which combine good monochromatic light correction, or high imaging accuracy, with low aberrations, while keeping the use of materials at very high numerical apertures. Is the purpose of reaching. Many aspheric surfaces are usually provided, but only eight should preferably be provided. It is beneficial if at least three aspheric surfaces are arranged in the second lens section following the beam splitter. It is particularly convenient if at least one aspheric surface is arranged in the vicinity of the stop surface from the point of view of requiring correction of spherical aberration and coma. In this case, if the ratio of the outer edge ray height at the surface to the aperture radius at the stop is in the range of about 0.8 to about 1.2, ie the outer edge ray height at the aspheric surface is A particularly effective correction is obtained if it is approximately equal to the maximum outer edge ray height occurring in the vicinity.
[0051]
In order to be able to effectively correct distortions and other field aberrations, it is beneficial to provide at least one aspheric surface in the field zone. For designs with an intermediate image, the points in the vicinity of the viewing zone are in the vicinity of the object plane, in the vicinity of the image plane, and in the vicinity of at least one intermediate image. These field surfaces located close to the field plane preferably have a ratio of the outer edge ray height above them to the associated system stop radius of less than about 0.8, preferably less than 0.6. It is characterized from that.
[0052]
If at least one aspheric surface is located in the vicinity of the field plane and at least one aspheric surface is located in the vicinity of the metering stop, it is useful to be able to adequately correct all the above mentioned imaging errors. is there.
[0053]
Embodiments having at least one intermediate image have at least one other field plane in addition to the system stop and at least one conjugate stop plane in addition to the object plane and the image plane, which is effective. This means that there is an additional degree of freedom to embody a non-spherical surface.
[0054]
In some embodiments, an advantageous configuration, particularly a reduction in the overall length of the projection lens, is facilitated by providing one or more deflection mirrors. Preference is given to arranging the deflection mirror following the physical beam splitter of the second lens section. The implementation of the deflection mirror allows the reticle (positioned in the object plane) and the wafer (positioned in the image plane) to be oriented parallel to each other, which is particularly desirable for scanner operation. In many embodiments, a deflecting mirror can be provided close to the beam splitter in order to allow a part of the lens to be designed compactly, so that between the physical beam splitter and the deflecting mirror that follows in the optical column. Does not have a lens. This also reduces the number of lenses to be mounted vertically (placed straight), which in the preferred embodiment can be less than 4 and in particular less than 3.
[0055]
The foregoing and other arrangements will be apparent from the claims, specification and drawings, each of the related independent arrangements being embodied in the present invention, other areas of implementation and in its own patentable embodiments. , Alone or in the form of a subset combination. Embodiments of the invention have been described with reference to the drawings.
[0056]
In the following description of the preferred embodiment of the present invention, the term "optical axis" refers to a sequence of straight lines or straight line segments passing through the center of curvature of the associated optical element, where the optical axis is bent by a deflecting mirror or other reflective surface. It is done. If the direction and distance are directed towards the image plane or towards the substrate to be illuminated, they are referred to as the “image edge” direction or distance and if they extend towards the object. If it is directed along that segment of the existing optical axis, it should be designated as the “object end”. In the case of the example shown here, the object may be an integrated circuit or other pattern, for example a mask (reticle) that supports the grating. In the example represented here, the image of the object is projected onto a wafer covered with a layer of photoresist that functions as a substrate. However, other types of substrates such as liquid crystal display components or substrates for optical gratings are also feasible.
[0057]
Next, the configurations of the various embodiments which are identical or corresponding are usually given the same reference numerals in all cases for the sake of clarity. The surface numbers in the various embodiments correspond to the surface numbers appearing in the associated table.
【Example】
[0058]
The configuration of a catadioptric reduction lens 100 according to the present invention is depicted in FIG. 1 based on its first embodiment, and a pattern image on a reticle or the like placed on the object plane 101 is placed on the image plane 103. It serves to project on a reduced scale, for example a 4: 1 scale, during which exactly one real intermediate image 102 is generated. The lens 100 has a catadioptric first lens section 104 followed by a purely refractive second lens section 105 disposed between the object plane and the image plane. The catadioptric lens section 104 comprises a physical beam splitter 106 having a plate beam splitter surface 107 that is tilted with respect to the optical axis and a mirror group 108 that includes an imaging concave mirror 109.
[0059]
The second reduced lens section 105 has a flat plate deflecting mirror 110 inclined at an angle of 45 ° with respect to the optical axis, and in parallel with reflection at the beam splitting surface 107, an object plane 101 parallel to the wafer disposed on the image plane 103. Can be tilted, which simplifies the operation of the mask and wafer in scanning mode and follows the intermediate image 102. As an alternative to this angular layout, the second lens section may have a linear layout with no deflection mirrors, or may be based on that version with one or more deflection mirrors.
[0060]
As can be seen from FIG. 1, light from the illumination system (not shown) is incident on the projection lens from that side of the object plane 101 away from the image plane, and within that course it is It passes through a mask arranged on an object plane arranged at an object end working distance exceeding 30 mm in front of the plane parallel plate 111 forming the element. This system is configured so that it has a preferred polarization axis before the light is incident on the projection lens, which in particular emits partially polarized light whose illumination device in front of the projection lens has a predetermined degree of polarization. It can be achieved by configuring as follows. If necessary, for the purpose of having depolarization near the reticle, the vicinity of the object plane 101 may be placed between two optical elements, the first of which converts incident partially polarized light into circularly polarized light. Subsequently, the reticle converts circularly polarized light into mainly linearly polarized light. These optical elements may be laid out in a sandwich arrangement with respect to the reticle and may be formed, for example, from a quarter wave plate.
[0061]
After passing through the incident plate 111, this light is mainly linearly polarized immediately before entering the beam splitter 106, but is projected onto the positive lens 112 disposed immediately before the beam splitter 106. Thus, the divergent rays coming from the object are collected and collimated so that variations within the incident angle (also referred to as the incident angle) in the vicinity of the beam splitter do not become too large on the first pass. The incident angle varies by approximately ± 10 ° from an angle of approximately 45 ° between the beam splitter surface and the optical axis. Within the beam splitter, light passes through its flat beam splitting surface 107, which is tilted with respect to the optical axis at an angle of about 45 °, and in this example it is p-polarized with respect to the plane of incidence. It is configured to transmit light and pass it toward the concave mirror 109. After passing through the beam splitter, it passes through a quarter wave plate (not shown), passes through a pair of large diameter negative lenses 113, 114 placed in the immediate vicinity of the concave mirror 109, and enters the concave mirror 109. Hits the surface. Following its reflection by the concave mirror, the circularly polarized light in the vicinity of the concave mirror passes through the quarter wave plate, which reconverts it to linearly polarized light, and its polarization axis once again becomes And 90 ° with respect to the polarization axis. The beam splitting surface 107 then reflects this s-polarized light, and the light reflected by the concave mirror is deflected towards the refractive second lens section following the beam splitter. Here, the light first passes through a positive lens 115 disposed in the immediate vicinity of the beam splitter, which is disposed between the beam splitter and the intermediate image 102 and is spaced from the intermediate image. The deflection mirror 110 deflects light coming from the intermediate image toward the other optical components 116-130 of the refractive lens section, which images the intermediate image 102 on the image plane 103.
[0062]
The optical data for the lens and other elements of this example are summarized in Table 1, with the leftmost column indicating the number of the specified surface that is refraction, reflection, or other involved, and the second column. Indicates the radius r [mm] of the surface, the third column indicates whether the surface involved is an aspheric surface (AS), and the fourth column is the distance d [mm] between the surface involved and the next surface. The parameter is referred to as the “thickness” of the optical element following the surface, column 5 indicates the material used to manufacture the optical element, and column 6 indicates the refractive index of the material. Column 7 shows the effective (usable) radius of the surface. The eighth column shows the names of some surfaces.
[0063]
In the case of the embodiment depicted in FIG. 1, eight surfaces, namely surfaces 4, 11 or 13, 28, 31, 42, 47, 49 and 51, are aspheric. Table 2 shows the data associated with these aspheric surfaces so that their shape can be calculated using the following equation:
[0064]
p (h) = [((1 / r) h ² ) / (1 + SQRT (1- (1 + K) (1 / r) ² h ² ))] + C1 ・ h ^Four -C2 ・ h ⁶ + ....,
Where r is the local radius of curvature of the surface and h is the distance from the optical axis to the point above it. p (h) represents the distance of the point from the vertex of the surface, measured along the z direction, that is, along the optical axis. The constants K, C1, C2, etc. are shown in Table 2.
[0065]
The optical system 100 can be reproduced using this data, but is designed for use at an operating wavelength of about 157 nm, so that all lenses made with calcium fluoride are 1. It has a refractive index n of 55841. This system has an object field size of 26 mm × 7 mm. The numerical aperture NA at the edge of the image is 0.85.
[0066]
Some advantageous configurations of this system are described in more detail below. In the depicted embodiment, the beam splitter 106 has a pair of right angle prisms that are coupled in the vicinity of the beam splitting surface 107 that together form a beam splitter cube (BSC). In other embodiments, shapes other than this cube shape may be provided. A thin optical coating passes on the first pass incident light, e.g. light that is p-polarized with respect to the entrance plane, and reflects s-polarized light coming from the concave mirror, whose polarization axis is rotated up to 90 °, It is provided in the vicinity of the beam split surface. This beam splitter is thus a polarizing beam splitter, and this light loss is minimized compared to the case of using a reflective film that partially transmits in the vicinity of the beam splitting surface. is there.
[0067]
In another embodiment, the beam split coating provided on the beam splitting surface is such that light coming from the object plane is first reflected towards a concave mirror that can be placed at the end of the second lens section opposite the beam splitter cube. Configured to be. The light reflected by the concave mirror to the beam split coating is then passed through the second lens section, which rotates its polarization axis. FIG. 2 and Tables 3 and 4 show an example (second example) of that type of projection lens 100 ′, as far as the optical surface type and arrangement are concerned, the example depicted in FIG. 1 otherwise. Not at all different.
[0068]
Instead of this type of beam splitter, a physical beam splitter can also be implemented by inserting a parallel plane plate or other optical element having a similar effect into the beam path inclined at a predetermined angle therefrom. For example, a beam splitter plate having a free-form correction surface that corrects imaging errors such as axial coma and axial astigmatism is also feasible.
[0069]
Compared to many common configurations, the beam splitter 106 is small, which means that a small amount of material is required for its manufacture. This is due to the fact that in this particular embodiment the beam splitter is placed in a region where the outer edge ray height is low, where it is placed close to both the object plane and the intermediate image. It is immediately obvious from what is done. In the depicted example, the outer edge ray height at the beam splitter that projects onto the plane orthogonal to the optical axis at the point where the beam split surface 107 intersects the optical axis is 70% of the outer edge ray height at the concave mirror. Smaller, especially less than about 40%. A small beam splitter volume is also favorably affected by the relatively strong refractive power being placed in the optical near field of the object plane 101. This refracting power is provided in part by a positive lens 112 placed in front of the beam splitter that collimates the diverging light beam coming from the object, and a slightly divergent beam onto the lower edge light beam height and the first pass of the beam splitter. Provide both. This positive lens 112 also preferably affects the telecentricity of the object end of the projection lens. Another positive lens 115 is located near the intermediate image, where the outer edge ray height is less than about 30% of the outer edge ray height at the concave mirror. This positive lens favors a low outer edge ray height within the refractive lens section, which allows the adoption of this section configuration to save material. These positive lenses 112, 115 also favorably affect the correction state of the intermediate image 102, where they correct, for example, distortion.
[0070]
Since the optical system includes the intermediate image 102, there are two conjugate stop planes, one of which is located near the concave mirror 109 and the second stop plane (surface 41) is freely accessible, Is located between the positive meniscus lens 124 and the negative lens 125 in the second lens section that guides the light into the optical column. Because of its accessibility, the latter lens should preferably be used as a system stop. The aspherical surface (surface 42) is preferably used to correct spherical aberration and coma in the case of an aspherical surface (surface 11 or 13) placed precisely in the vicinity of the concave mirror. It is also arranged in the immediate vicinity. This particular embodiment effectively corrects for distortion and other field aberrations. It is also provided with a near-field aspheric surface (aspheric surface arranged near the field plane), for example the entrance surface 4 of the first positive lens 112 of the projection lens.
[0071]
The color collection of the projection lens is preferably influenced by a pair of negative lenses 113, 114 having a large outer edge ray height just in front of the concave mirror 109, and a large amount of negative refractive power is placed between the beam splitter and the concave mirror. Provided in the lens section. In the case of the depicted example, the absolute value of the combined negative power of these negative lenses 113, 114 is more than twice the reciprocal of the distance between the object plane and the concave mirror. There is no positive lens in this lens section, which allows the design of these negative lenses such that their refractive surface has the desired relatively low curvature. A further advantage with regard to mechanical stability and the desired design of the projection lens arises from the fact that two lenses are included in the projection lens arm that supports the concave mirror 109.
[0072]
It is beneficial for chromatic aberration that the lens section located between the beam splitter and the concave mirror is overcorrected, where in the depicted example the overcorrection is in front of another lens section, ie the beam splitter. 70% of the under-collection of the entire lens arrangement following the positive lens 112 and the beam splitter, and even 80% to 90% can be compensated.
[0073]
The specifications of the projection lens 100 "of the third embodiment depicted in FIG. 3 are described in Tables 5 and 6, where the optical elements and optical surface numbering appearing there are depicted in FIGS. 3 corresponds to that used in the case of the embodiment, one of the main differences between the embodiment depicted in FIG. The axial distance between the beam splitter and the beam splitter followed by the lens in the optical train is much larger than those in the previous embodiment, which is the horizontal side including the object plane 101 and the mirror group 108 (all projection lenses are (When assembled) makes it possible to increase the measured distance along the arm input axis, which makes the space more available and in that area embodies the components of the reticle stage More simple This advantage can be obtained at the expense of a slight increase in the volume of the beam splitter 106. However, in this embodiment as well, the volume of the beam splitter remains small. There, in particular, the radius of the beam splitter, measured along the direction perpendicular to the optical axis, can be much less than 70% or 60% of the radius of the concave mirror 109.
[0074]
Various configurations also include shifting the intermediate image 102 away from the beam splitter, i.e., near the deflecting mirror, and placing a positive lens 115 positioned between these components at a long distance from the beam splitter. to enable.
[0075]
The fourth embodiment shown in FIG. 4 and Tables 7 and 8 represents another embodiment of a dual telecentric projection lens according to the present invention, which is 26 mm × 7 mm for a 4 × image reduction magnification. It has an image field at the image edge to be measured and a numerical aperture NA of NA = 0.85 at the image edge for total color collection. The numbering of the optical elements and optical surfaces corresponds to that of the previous embodiment. The main difference between this embodiment and the previous embodiment is that the first positive lens 115 following the beam splitter 106 is placed behind rather than in front of the deflecting mirror 110 and is therefore placed horizontally. This preserves the interference space between the beam splitter and the deflecting mirror without a lens. This embodiment provides the advantage of simpler lens placement, and a scheme that ensures a stable placement over time if they are placed in a horizontal arrangement (in the case of a vertical optical axis) rather than a vertical arrangement This is because it is easier than usual to place the lens mechanically.
[0076]
From the fifth embodiment shown in FIG. 5 and Tables 9 and 10, it can be seen that in the present invention there is no optical element in the space between the object plane 101 and the entrance surface of the beam splitter, especially without an isolated lens. I understand. In this particular embodiment, all the positive refractive power provided in the optical near field of the object plane is provided by a single positive lens 112, which is advantageous, inter alia, for telecentricity at the object end. This is arranged following the exit surface of the beam splitter facing the concave mirror between the beam splitter and the mirror group. This lens is passed twice, but provides that the chief ray height along the optical axis between the concave mirror 109 and the refractive second lens section is relatively low within that section, which results in A relatively small lens radius makes it possible to save lens material. The positive lens 112 may also be relatively small because it is located in the vicinity where the outer edge ray height is low (less than 30% of the outer edge ray height at the concave mirror). In addition, adjusting the refractive power of the positive lens 112 can affect the position of the intermediate image 102, which in the illustrated embodiment is a beam splitting surface 107 in the beam splitter 106. In the vicinity.
[0077]
The sixth embodiment of the reduction lens 200 depicted in FIG. 6 and Tables 11 and 12 is designed with respect to the present invention to be able to keep the range of angles of incidence on the beam splitting surface narrow for at least one propagation direction. It also expresses that it is possible. An incident element 211 having only a weak optical effect is followed by a meniscus lens 212 having a positive refractive power, and its bent surfaces 3 and 4 are bent toward the image plane. The lens is positioned a short distance before the entrance surface of the beam splitter 206, which mainly contributes to greatly collimating the light incident on the beam splitter surface 207 of the first pass, where air In the first pass physical beam splitter, the angle between the outer edge ray and the optical axis is less than about 10 °, in particular less than about 5 °. The nearly parallel beam that passes through the beam splitter and goes to the concave mirror 209 is expanded by three negative lenses 215, 213, 214, one of which (215) is placed near the beam splitter and the other two (213, 214) is arranged in the mirror group 208 located immediately before the concave mirror 209. This lens 215 provides the advantage of expanding the convergent beam reflected by the concave mirror 209, but is intended to cause a relatively small change in the angle of incidence on the beam splitter surface as it returns to the beam splitting surface 207. . A lens group having a positive lens 216 and a meniscus lens 217-219 disposed immediately before the intermediate image 202 is disposed between the beam splitter 206 and the beam deflection mirror 210, and greatly corrects third-order and higher-order distortions. . The light beam reflected by the deflecting mirror is focused on the plane of the wafer by the multi-lens final lens section. This arrangement also provides a freely accessible stop surface 49 in the reflective lens section, which is located near the wafer.
[0078]
For this particular configuration, the beam splitting surface is, of course, adapted to match the polarization state of the light incident on the system, and the beam splitter is employed reflecting on the first pass and transmitting on the second pass. It has become so.
[0079]
Another layout of the catadioptric reduction lens 100 in accordance with the present invention is depicted in FIG. 7 based on the seventh embodiment and placed on the object plane 101 while creating exactly one real intermediate image 102. A pattern of a reticle or the like is imaged on the image plane 103 on a reduced scale, for example a 4: 1 scale. The lens 100 has a catadioptric first lens section 104 followed by a purely refractive second lens section 105 disposed between the object plane and the image plane. The catadioptric lens section 104 comprises a physical beam splitter 106 having a mirror group 108 including a flat beam splitter surface 107 and an imaging concave mirror 109 tilted with respect to the optical axis.
[0080]
The demagnifying second lens section 105 has a flat deflecting mirror 110 that is tilted with respect to the optical axis, which, with respect to reflection at the beam splitter surface 107, is in an object plane 101 parallel to the wafer located in the image plane 103. It is possible to tilt the placed mask, which simplifies handling the mask and wafer placed in front of the intermediate image 102 in scan mode. It is also feasible to have a configuration without a deflection mirror or one or more deflection mirrors.
[0081]
The layout between the object plane 101 and the beam splitter 106 is similar to that depicted in FIGS. 1-4, which has a plane parallel entrance plate 111 and a positive lens 112, where the latter is a curved surface. Is a meniscus lens bent toward the object plane.
[0082]
After passing through the incident plate 111, this light is mainly linearly polarized just before it enters the beam splitter 106, but is incident on a positive lens 112 placed just before the beam splitter 106, which In particular, divergent rays coming from an object are collected and collimated, but the change in incident angle near the beam splitter is not too great on the first pass. The angle of incidence is in the range of ± 10 ° around a tilt angle 18 normal to the beam splitting surface 107 with respect to the segment 15 of the optical axis perpendicular to the object plane. The inclination angle 18 is about 49 ° (see FIG. 8). Within the beam splitter, the light passes through its flat beam splitting surface 107, which in this particular example is about 98 ° toward the concave mirror 109 for incident light, for example s-polarized with respect to the incident surface. The reflection angle 19 is configured to reflect. The optical axis is bent at this angle, although its segment 16 passing between the beam splitting surface 107 and the concave mirror 109 is inclined in this way towards the image plane away from the object plane. The light reflected by the beam splitting surface passes through a quarter-wave plate (not shown), passes through a pair of large-diameter negative lenses 113 and 114 disposed in the immediate vicinity of the concave mirror 109, and enters the concave mirror. It hits 109 reflective surfaces. Following its reflection by the concave mirror, the light is circularly polarized in the vicinity of the concave mirror and passes through a quarter wave plate, which reconverts it to linearly polarized light, whose polarization axis once again becomes its It is rotated up to 90 ° with respect to the original polarization axis. The beam splitting surface 107 then transmits this p-polarized light because the light reflected by the concave mirror is directed towards the refractive second lens section following the beam splitter.
[0083]
As soon as it exits the beam splitter, the light hits the deflecting mirror 110 following the beam splitter, where there are no optical components in the space between the two. This deflection mirror is tilted with respect to the beam path, and the deflection angle 20 is through which the optical axis is bent at the deflection mirror 110 but between 180 ° between the first segment 15 and the second segment 16 of the optical axis. The size of the deflection angle 19 is subtracted. In this particular case, the angle 20 is about 92 °, which orients the optical axis segment 15, which is perpendicular to the object plane parallel to the optical axis segment 17 perpendicular to the image plane 103. is there. The deflection mirror 110 is immediately followed by a positive lens 115 that further collects the convergent light at the deflection mirror, and is intended to produce an intermediate image 102 following the lens in the optical train. As can be seen from FIG. 7, the lens can be a prefix cone, ie a semi-lens or a partial lens, for the purpose of simplifying placing it near the beam splitter. The intermediate image is on the outside, so that the positive lens 115 is thus arranged in the refractive second lens section 105. These optical components 116-130 follow the intermediate image in the light train and serve to image the intermediate image on the image plane 103 and correct any imaging errors that appear in the vicinity of the intermediate image 102.
[0084]
The optical data for this example lens and other elements are summarized in Table 13. In the embodiment depicted in FIG. 7, eight surfaces, namely surfaces 4, 11 or 13, 30, 33, 44, 49, 51, and 53, are aspheric. Table 14 shows the relevant data for these aspheric surfaces.
[0085]
The optical system 100 can be reproduced using this data, but all propagation optical components designed for use at an operating wavelength of about 157 nm and thus manufactured using calcium fluoride are 1. It has a refractive index n of 55841. This system has an object field size of 26 mm × 7 mm. The numerical aperture NA at the edge of the image is 0.85.
[0086]
Some advantageous configurations of this system are described in more detail below. Unlike the conventional beam splitter, the beam splitter 106 differs from 90 ° by a large margin, in particular 90 °, because the beam splitting surface is tilted with respect to the segment 15 of the optical axis perpendicular to the object plane which is significantly greater than 45 °. Allows different beam deflections beyond 0 °, which places the beam splitter block 106 relatively close to the object plane without the concave mirror group 108 physically intervening near the reticle stage (not shown). Which extends into the object plane for the purpose of holding the reticle to be placed in the object plane 101 and scanning it across the object plane. Its proximity to the object plane also allows the beam splitter to be placed in a region with a low outer edge ray height, which makes it possible to use a beam splitter with a small volume. The resulting reflection angle at their beam splitting surfaces is different from that of conventional beam splitters because the average angle of incidence on the beam splitter surface shifts to a larger angle of incidence, which is Create new degrees of freedom in the area of coating design. With respect to the distribution of the incident angles, the relationship at the deflecting mirror 110 immediately following the beam splitter is reversed because it deflects the incident light much less than 90 °, ie about 82 °. is there. The deflecting mirror may thus be covered with a reflective coating, which is designed with an average incident angle of about 41 °, which is probably a more desirable coating design, and perhaps a conventional 45 ° mirror is used. Allows higher reflectivity to be reached. A desirable tilt angle is, for example, in the range of about 35 ° to about 42 ° -44 °.
[0087]
In the depicted embodiment, the beam splitter 106 has a pair of angle prisms that are coupled together to form the beam splitting surface 107 and, despite its deviation from the cube shape, “ A trapezoidal beam splitter cube, referred to as a beam splitter cube "(BSC), is formed. In other embodiments, beam splitters having other shapes may also be provided, but for the purpose of saving material, a shape whose volume is optimized so that the total volume slightly exceeds the maximum irradiation volume is preferred. Polarizing beam splitters of the type described here are preferred, since light loss in the vicinity of the beam splitting surface is minimized compared to the case of partial transmission through the reflective coating.
[0088]
There is no lens in the space between the beam splitter 106 and the deflecting mirror 110, which gives the advantage of simple lens equipment. This is because if they are mounted in a horizontal arrangement (in the case of a vertical optical axis) rather than a vertical arrangement, lenses that are mechanically installed in a manner that guarantees a stable arrangement over time is usually easier. is there. Furthermore, due to the inclination of the second segment 16 of the optical axis, special placement is required here, in order to be able to place a lens tilted off-axis. However, it is avoided in the case of the depicted embodiment.
[0089]
In another embodiment, the beam split coating provided in the vicinity of the beam splitting surface is on the extension of the first segment 15 of the optical axis where the light coming from the object plane is located on the side of the beam splitter opposite the object plane. It is configured to be sent first towards the concave mirror placed. The light that is reflected back to the beam splitter is then reflected towards the second lens section, followed by rotation of its polarization axis. The beam splitting surface can be tilted with respect to the optical axis at an angle different from 45 °, but also in this type of embodiment, the segment 15 of the optical axis that traverses the beam path is tilted away from and parallel to the object plane. Instead of running, it starts at the beam splitter cube.
[0090]
Regarding the size of the beam splitter, its arrangement in the vicinity of the low outer edge ray height, intermediate image, aspheric surface, and color collection, those descriptions made for the first embodiment are described in this seventh embodiment. Applied with no exceptions or similar concepts.
[0091]
An alternative configuration of a catadioptric reduction lens 100 according to the present invention is depicted in FIG. 9, wherein a scaled image of a pattern on a reticle or the like placed on the object plane 101 is reduced to the image plane 103; For example, it plays the role of projecting on a 4: 1 scale, during which exactly one real intermediate image 102 is generated. The lens has a catadioptric first lens section 104 followed by a purely refractive second lens section 105.
[0092]
This projection lens has a flat plate deflecting mirror 110 inclined at an angle of 45 ° with respect to the optical axis, and is arranged on an object plane 101 parallel to the wafer arranged on the image plane 103 in cooperation with reflection on the beam splitting surface 107. It is possible to tilt the mask. As an alternative to this angular layout, the second lens section may have a linear layout with no deflection mirrors, or may be based on that version with one or more deflection mirrors. The angle of incidence of the beam splitting surface is much larger or much smaller than 45 °, for example, differing therefrom by an amount in the range of about 1 ° to about 10 °, which is also feasible, for example the side supporting the concave mirror The arm can be tilted, which leaves more free space available in the vicinity of the reticle surface.
[0093]
As can be seen from FIG. 9, light from an illumination system (not shown) is incident on the projection lens from that side of the object plane 101 away from the image plane, and within that course it is the first optical of the projection lens. It passes through a mask arranged on an object plane arranged at an object end working distance exceeding 30 mm in front of the plane parallel plate 111 forming the element. This system is configured so that it has a preferred polarization axis before the light is incident on the projection lens, which in particular emits partially polarized light whose illumination device in front of the projection lens has a predetermined degree of polarization. It can be achieved by configuring as follows. A version using circularly polarized incident light with a λ / 4 plate sandwich arrangement for the reticle (see FIG. 1) is also feasible.
[0094]
After passing through the incident plate 111, this light is polarized mainly linearly just before entering the beam splitter 106, and since no lens is disposed between the beam splitter and the object plane, the light is immediately applied to the beam splitter 106. Hit it. Within the beam splitter, the light strikes its flat beam split surface 107, which is tilted with respect to an optical axis at an angle of about 45 °, which in this embodiment is configured to reflect incident light, which Is, for example, s-polarized with respect to the entrance surface and deflects it towards the concave mirror 109. After passing through the beam splitter, it passes through a quarter wave plate (not shown), passes through a pair of large diameter negative lenses 113, 114 placed in the immediate vicinity of the concave mirror 109, and enters the concave mirror 109. Hits the reflective surface. Following its reflection by the concave mirror, the circularly polarized light in the vicinity of the concave mirror passes through the quarter wave plate, which reconverts it to linearly polarized light, and its polarization axis once again becomes its And 90 ° with respect to the polarization axis. The beam splitting surface 107 then reflects this p-polarized light, and the light reflected by the concave mirror is passed towards the refractive second lens section following the beam splitter. The light coming from the beam splitter is deflected by the deflecting mirror 110 towards the other optical components 115-129 of the refractive lens section, where the first lens 155 of the second lens section has a positive refractive power, In front of the intermediate image, which is in a freely accessible position within the segment of the second lens section without the lens.
[0095]
The optical data for these lenses and other elements of this example are summarized in Table 15. In the embodiment shown in FIG. 9, eight surfaces, ie 9 or 11, 19, 27, 30, 39, 44, 46, 46 and 48, are aspheric. Table 16 shows the relevant data for these aspheric surfaces.
[0096]
Some advantageous configurations of this system are described in more detail below. In the depicted embodiment, the beam splitter 106 has a pair of right angle prisms connected in the vicinity of the beam splitting surface 107 forming a beam splitter cube (BSC). In other embodiments, shapes other than this cube shape may be provided. In another embodiment, the beam splitter coating provided in the vicinity of the beam splitter surface 107 is initially directed toward a concave mirror placed on the side of the beam splitter cube where the light coming from the object plane faces away from the object plane. Configured to be sent. The light reflected by the concave mirror and returning to the beam splitter cube is reflected toward the second lens section and rotates its polarization axis.
[0097]
Instead of this type of beam splitter, a physical beam splitter can also be implemented by inserting a parallel plane plate or other optical element having a similar effect into the beam path inclined at a predetermined angle therefrom. For example, a beam splitter plate having a free-form correction surface that corrects imaging errors such as axial coma and axial astigmatism is also feasible.
[0098]
Compared to many common configurations, the beam splitter 106 is small, which means that a small amount of material is required for its manufacture. This is due to the fact that in this particular embodiment the beam splitter is placed in a region where the outer edge ray height is low, where it is placed close to both the object plane and the intermediate image. It is immediately obvious from what is done. In this particular example, the outer edge ray height at the beam splitter that projects onto the plane orthogonal to the optical axis at the point where the beam split surface 107 intersects the optical axis is 70% of the outer edge ray height at the concave mirror. Smaller, especially less than about 40%. This is favorably influenced by the absence of a lens placed between the object plane and the image plane, and the beam splitter can be moved relatively close to the image plane, i.e. in the vicinity where the outer edge ray height is low. . The catadioptric section 104 does not include any positive lens, only the negative lens, ie the two lenses 113, 114 are arranged between the beam splitter and the concave mirror 109. The total positive power of this section is provided by the concave mirror 109. The catadioptric section 104 thus has a two lens arrangement, which is particularly beneficial for projection lens assembly, mechanical stability, material requirements, alignment, and transmission.
[0099]
The first positive lens 115 following the object plane is located in the second lens section and in the near field of the intermediate image, where the outer edge ray height is less than about 30% of the outer edge ray height at the concave mirror. . This positive lens prefers a low outer edge ray height in the refractive lens section, which allows the use of a section configuration that saves material. This positive lens 115 also preferably influences the correction state of the intermediate image 102, where it corrects, for example, distortion.
[0100]
The first positive lens 115 following the beam splitter 106 is arranged following the deflecting mirror 110 and thus can be placed horizontally, but this maintains the intervening space between the beam splitter and the deflecting mirror without a lens. This embodiment offers the advantage of simpler lens placement, a scheme that ensures a safe placement over the long term if they are placed in a horizontal arrangement (in the case of a vertical optical axis) rather than a vertical arrangement It is easier than usual to place the lens mechanically.
[0101]
The projection lens is non-telecentric at its object end, where the angle of the chief ray that is not parallel to the optical axis at the object plane can be advantageously influenced by a suitable choice of the refractive power of the positive lens 115. Yes, this makes it possible to adapt it to illumination systems with non-telecentric emission. Discrete from the telecentricity of the object edge can be beneficial where a reflective mask is used.
[0102]
The non-telecentric object end beam path therefore focuses the chief ray from the image field end to the center of the beam splitter, but allows for a particularly compact and low volume beam splitter configuration. Since no refractive component is placed between the object plane and the beam splitter, the beam splitter can be moved by the object plane, which is advantageous for small beam splitter volumes. In that case, which is the same as or similar to the embodiment depicted in FIG. 9, the beam splitter is manufactured from lithium fluoride, which can be replaced by mixed lithium fluoride based crystals if necessary. Lithium fluoride has a much lower intrinsic stress birefringence coefficient than calcium fluoride, which can also be used, but this can optimize the polarization properties of the beam splitter configuration, where It is particularly advantageous in conjunction with the small beam splitter volume used, which makes it possible to keep the length of the optical path short in the slightly birefringent material and thus keep the associated retardation small. . In addition, using a small beam splitter volume in conjunction with a deflecting mirror placed immediately following the beam splitter allows the segment of the optical axis to pass through the center of the object plane and the segment of the optical axis to pass through the center of the image plane. It is advantageous to maintain a short axial distance between the two, which facilitates simple coupling of such a projection lens into a wafer stepper.
[0103]
Since the optical system includes the intermediate image 102, there are two conjugate stop surfaces, one of which is located in the vicinity of the concave mirror 109, the second stop surface (surface 38) is freely accessible, and the light Located between the positive meniscus lens 123 and the negative lens 124 in the second lens section that follows in the row. Because of its accessibility, the latter lens should preferably be used as a system stop. The aspheric surface (surface 39) can be used to correct spherical and coma aberrations, preferably as in the case of an aspheric surface (surface 9 or 11) placed precisely in the vicinity of the concave mirror. It is also placed in the immediate vicinity of the stop. This particular embodiment also makes it possible to effectively correct distortions and other field aberrations. This is because a near-field aspheric surface, for example, the incident surface 19 of the first positive lens 115 of the projection lens is also provided.
[0104]
The color collecting properties of the projection lens are particularly preferably influenced by the pair of negative lenses 113, 114, which immediately exceed the concave mirror 109 and have a large negative refractive power in the lens section located between the beam splitter and the concave mirror. It has a large outer edge ray height. In this particular example, the absolute value of the negative refractive power of these coupled negative lenses 113, 114 exceeds twice the mutual distance between the object plane and the concave mirror. There are no positive lenses in this lens section, which makes it possible to configure them so that the refractive surfaces of these negative lenses have the desired relatively low curvature. A further advantage with respect to the greater mechanical stability and desirable configuration of the projection lens arises from the fact that only two lenses must be included in that arm of the projection lens that supports the concave mirror 109.
[0105]
It is useful if the lens section located between the beam splitter and the concave mirror is overcorrected due to chromatic aberration, and in this particular example, the overcorrection is the overcorrection of all lens sections following the beam splitter. 70% or even 80% to 90% can be guaranteed, or the overcorrection can be overcorrected.
[0106]
The ninth embodiment shown in FIG. 10 and Tables 17 and 18 represents another embodiment of a dual telecentric projection lens according to the present invention, which has dimensions of 26 mm × 7 mm for four times image reduction magnification. The wafer edge image field of view and the image edge numerical aperture NA for all achromatics have NA = 0.85. The numbering of the optical elements and optical surfaces corresponds to those in the above embodiment.
[0107]
Once again, it can be seen that the space between the object plane 101 and the entrance surface of the beam splitter is kept without optical elements, in particular without isolated lenses. In this particular embodiment, all the positive power provided in the optical near field of the object plane is provided by a single positive lens 112, which is a beam directed to the concave splitter of the beam splitter and mirror group. It is placed following the exit surface of the splitter. This positive lens provides the object-end telecentricity of the projection lens and eliminates the full field dependence of the angle of incidence on the beam splitting surface 107. Light rays from various fields thus enter the beam split coating at essentially the same angle, which simplifies its construction and thereby helps to provide a uniform optical effect. The maximum angle of incidence on the first path of the beam splitter decreases in the range of approximately ± 15 °. The second positive lens 112 is passed twice, but the chief ray height along the optical path between the concave mirror 109 and the second lens section is relatively low in the second lens section, which results in comparison This makes it possible to save lens material because of the small size of the lens.
[0108]
For this particular configuration, the beam splitting surface can, of course, be adapted to match the polarization state of the light incident on the system, but the beam splitter can propagate on the first path and reflect on the second path. To be used.
[0109]
All embodiments have a number of features, only a few of which are described below. These systems are typically double telecentric so that defocus errors on the reticle and wafer edges are avoided. Non-telecentric incidence is beneficial where a reflective mask or object is used and can be performed in conjunction with the present invention, but this will adapt the refractive power of the first lens or lens group close to the matching object plane. Where the design principles underlying the present invention remain unchanged. A numerical aperture of NA = 0.85 is achieved with a field size of 26 mm × 7 mm in all cases.
[0110]
Any embodiment is a plane-parallel or nearly plane-parallel plate, i.e. an optical element with little or no optical effect, so that its first optical element immediately follows the optical plane and / or its final optical element is of the image plane. It is possible to have it in front of it, which makes the projection lens relatively resistant to changes in the refractive index of the flushing gas due to pressure fluctuations and, if necessary, physical damage.
[0111]
The catadioptric section has a magnification of about 1. The main contribution to the total reduction (4: 1) for all these projection lenses is generated by the second lens section, which is purely refractive with their reduction magnification, and the positive lens is more aperture stop than the negative lens. Located following the face. Other full image magnification / reduction magnifications, eg, large reduction magnifications, can be changed, particularly by forming a change to the second lens section.
[0112]
The change in incident angle is small for all deflecting mirrors, where the range of their change should preferably be less than 30 °. In particular, their angle of incidence is in all cases limited to the range of about 30 ° to about 60 °, which also allows the use of simple, highly uniform mirrors with a reflective coating. In the case of beam deflection embodiments greater or less than 90 °, it can be seen that this is effective because of the beam deflection that occurs at the beam splitter, which is due to its structure or beam deflection at one or more beam deflection mirrors, This is immediately possible in conjunction with the present invention. However, the stated range of incident angles should be adjusted accordingly.
[0113]
It is particularly effective if the maximum lateral dimension of the beam splitter block is less than 70% of the concave mirror diameter, often less than about 50%. All embodiments make it possible to use a beam splitter block having a bulk material other than a cube shape, for example a positive or incorrect minimum shape. In particular, the shape of the beam splitter blocks can be adapted to the beam path within the beam splitter so that there are essentially no unirradiated zones. The block whose volume is optimized may have, for example, a cube shape.
[0114]
The present invention has been described based on several selected exemplary embodiments, but on-axis providing telecentric object end and image end beam paths, sufficient working distance for micrography, and longitudinal chromatic aberration (CHL). It makes it possible to provide optical systems and to maintain a reasonable range of angles of incidence on the beam splitter surface, resulting in a small volume of material for manufacturing those physical beam splitters. These advantages can be achieved for high image end numerical apertures, where numerical aperture NAs above 0.7 or even 0.8 are feasible. These image edges can also be enlarged compared to that of a general design.
[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Brief description of the drawings]
[0115]
FIG. 1 is a cross-sectional view showing a plurality of lenses according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a plurality of lenses according to a second embodiment of the present invention.
FIG. 3 is a sectional view showing a plurality of lenses according to a third embodiment of the present invention.
FIG. 4 is a sectional view showing a plurality of lenses according to a fourth embodiment of the present invention.
FIG. 5 is a sectional view showing a plurality of lenses according to a fifth embodiment of the present invention.
FIG. 6 is a sectional view showing a plurality of lenses according to a sixth embodiment of the present invention.
FIG. 7 is a sectional view showing a plurality of lenses according to a seventh embodiment of the present invention.
FIG. 8 is a detailed conceptual diagram showing the vicinity of the beam deflector depicted in FIG. 7;
FIG. 9 is a sectional view showing a plurality of lenses according to an eighth embodiment of the present invention.
FIG. 10 is a sectional view showing a plurality of lenses according to a ninth embodiment of the present invention.
[Explanation of symbols]
[0116]
15 First segment
16 Second segment
19 Deflection angle
100 catadioptric reduction lens
101 object plane
102 Intermediate image
103 Image plane
104 Catadioptric first lens section
105 Reduced second lens section
106 Beam splitter
107 Beam split surface
108 mirrors
109 Imaging concave mirror
110 Plate deflection mirror
111 Incident plate
113, 114 Negative lens
112, 115 positive lens
123 positive meniscus lens
124 negative lens
200 reduction lens
206 Beam splitter
207 Beam splitting surface
208 mirrors
209 concave mirror
210 Beam deflection mirror
211 Incident element
212 Meniscus lens

Claims (41)

A catadioptric first lens section having a physical beam splitter having a concave mirror and a beam splitting surface that images a pattern positioned in the object plane onto the image plane, and a second lens section disposed subsequent to the beam splitter, Placed between the object plane and the image plane,
The object plane is located at a working distance from the first optical surface of the projection lens;
Positive refractive power is placed in the optical near field of the object plane,
A catadioptric projection lens in which the beam splitter is placed in a zone with a lower outer edge ray height. Projection lens according to claim 1, characterized in that it is designed to produce at least one real intermediate image, which is preferably freely accessible. Projection according to claim 1 or 2, characterized in that the outer edge ray height in the optical near field of the object plane and / or intermediate image is less than about 30% of the outer edge ray height at the concave mirror. lens. Within the zone of low outer edge ray height located in the beam splitter, the projection of the outer edge ray height onto a plane perpendicular to the optical axis where it intersects the optical axis is approximately equal to the outer edge ray height at the concave mirror. Projection lens according to any one of the preceding claims, characterized in that it is in the range of 10% to about 70%. The projection lens according to claim 2, wherein the beam splitter is disposed in the vicinity of the intermediate image. 8. A beam splitter according to any one of the preceding claims, characterized in that the beam splitter is arranged in a zone where the outer edge ray height for propagation in both directions is less than about 70% of the outer edge ray height at the concave mirror. Projection lens. The beam splitter is composed of a beam splitter block having a shape away from the cube shape, the shape is preferably rectangular and the dimensions are preferably optimized so that its volume is minimized. A projection lens according to any one of the preceding claims. A projection lens according to any one of the preceding claims, wherein the maximum extension of the beam splitter across the optical axis is less than 70% of the diameter of the concave mirror. A positive refracting power is arranged between the object plane and the beam splitter, preferably a distinct one lens having a positive refracting power is arranged between the object plane and the beam splitter. The projection lens according to claim 1. 9. Projection lens according to any one of the preceding claims, characterized in that the zone between the object plane and the beam splitter has essentially no positive refractive power. 9. The projection lens according to claim 1, wherein a lens that stands up freely is not disposed in a zone between the object plane and the beam splitter. Projection lens according to any one of the preceding claims, characterized in that the positive refractive power is arranged in the optical near field of the intermediate image and / or the object plane following the beam splitter. Projection according to any one of the preceding claims, characterized in that the intermediate image is arranged at a distance behind the beam splitter and the positive refractive power is arranged between the beam splitter and the intermediate image. lens. Any of the preceding claims, characterized in that, in the beam splitter, the angle in air between the outer edge ray and the optical axis is less than 10 °, preferably less than 5 °, along at least one propagation direction. The projection lens according to Item 1. Projection lens according to any one of the preceding claims, characterized in that the catadioptric lens section comprises only a lens having a negative refractive power between the beam splitter and the concave mirror. Projection lens according to any one of the preceding claims, characterized in that the catadioptric section comprises at least two lenses having a negative refractive power between the beam splitter and the concave mirror. Projection lens according to any one of the preceding claims, characterized in that the catadioptric section comprises less than 4, in particular less than 3, lenses between the beam splitter and the concave mirror. Part of the catadioptric lens section between the beam splitter and the concave mirror is overcorrected due to longitudinal chromatic aberration so that it is compensated for at least 70%, preferably more than 85% of the overcorrection of other lens components. A projection lens according to any one of the preceding claims, characterized in that The lens having a positive refractive power is not positioned in the near field of the concave mirror, and the outer edge ray height in the near field is preferably more than 70% of the outer edge ray height in the concave mirror. A projection lens according to any one of the preceding claims. The beam splitter surface is arranged with an inclination angle with respect to the segment of the optical axis perpendicular to the object plane different from 45 °, and the difference between the inclination angle and 45 ° is preferably in the range of about 1 ° to about 10 °. The projection lens according to claim 1, wherein the projection lens is provided. The tilt angle is set so that the deflection angle included between the segment of the optical axis perpendicular to the object plane and the segment of the optical axis arranged following the bending at the beam splitting surface exceeds 90 °. The projection lens according to claim 20. The second lens section is provided with at least one deflection mirror arranged at an inclination angle different from 45 ° with respect to the optical axis, preferably so that the inclination angle of the deflection mirror and the inclination angle of the beam splitting surface match each other. The projection lens according to claim 20 or 21, wherein the image plane is arranged either parallel or orthogonal to the object plane. Projection lens according to any one of the preceding claims, characterized in that at least one lens of the second lens section is arranged between the beam splitting surface and the intermediate image. Projection lens according to any one of the preceding claims, characterized in that a positive refractive power is arranged between the beam splitting surface and the intermediate image. All the transmission optical components, in particular all lenses and beam splitters, are manufactured from the same material, in particular from crystalline fluorides, preferably calcium fluoride, or synthetic quartz glass. The projection lens according to any one of the above. The projection lens according to claim 1, wherein the beam splitter consists essentially of lithium fluoride. Projection lens according to any one of the preceding claims, characterized in that it is telecentric at its image end, preferably telecentric at both the object end and the image end. Any of the preceding claims characterized by having an image edge numerical aperture greater than about 0.7, the image edge numerical aperture being preferably at least 0.8, in particular about 0.85. The projection lens according to Item 1. Projection lens according to any one of the preceding claims, characterized in that it is designed for the use of ultraviolet light at wavelengths shorter than about 260 nm, in particular at wavelengths of about 157 nm or about 193 nm. Projection lens according to any one of the preceding claims, characterized in that at least one optical component, in particular at least one lens, has at least one aspheric surface. At least one aspheric surface is provided in the vicinity of the plane of the at least one stop, and the ratio of the outer edge ray height at the aspheric surface to the radius of the aperture of the system stop is about 0.8 to about 1.2. Projection lens according to any one of the preceding claims, characterized in that the aspherical surface is preferably configured to be in range. At least one aspheric surface is provided in the vicinity of the object plane and / or in the vicinity of the image plane, and / or in the vicinity of at least one intermediate image, the height of the outer edge ray on the aspheric surface and the aperture at the system stop. Projection lens according to any one of the preceding claims, characterized in that the aspheric surface is preferably arranged such that the ratio of radii is less than about 0.8. At least one aspheric surface is arranged in the vicinity of the plane of the stop and at least one aspheric surface is arranged in the vicinity of the object plane and / or the image plane and / or at least one intermediate image Projection lens according to any one of the preceding claims. Projection lens according to any one of the preceding claims, characterized in that the system stop is arranged at a distance from the beam splitter, preferably in the second lens section of the reduction magnification. A projection lens according to any one of the preceding claims, characterized in that a freely accessible stop surface is provided. The first optical element positioned closest to the object plane and / or the final optical element positioned closest to the image plane are each formed from a substantially plane parallel plate, respectively. The projection lens according to claim 1. Projection lens according to any one of the preceding claims, characterized in that at least one total reflection deflection mirror is provided, in particular the second lens section comprises at least one deflection mirror. Projection lens according to any one of the preceding claims, characterized in that the first optical component of the second section following the beam splitter is a deflection mirror. 40. A projection exposure system, wherein the projection lens is configured for any one of claims 1-38 for use in microlithography having an illumination system and a catadioptric projection lens. 40. Projection exposure system according to claim 39, characterized in that the illumination system is designed to emit partially polarized light. Providing a mask having a specified pattern;
Irradiate this mask with ultraviolet light having a specified wavelength,
A semiconductor device or other device that projects an image of the pattern onto a photosensitive substrate disposed in the vicinity of the image plane of a projection lens that uses a catadioptric projection lens matched to any one of claims 1-38 Manufacturing method of type micro device.

Images