Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
  • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70216—Mask projection systems
  • G03F7/70233—Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B13/00—Optical objectives specially designed for the purposes specified below
  • G02B13/14—Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
  • G02B13/143—Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation for use with ultraviolet radiation
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
  • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
  • G02B17/0647—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using more than three curved mirrors
  • G02B17/0657—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror using more than three curved mirrors off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70216—Mask projection systems
  • G03F7/70225—Optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements

Definitions

• the invention relates to a lens, in particular a projection objective, preferably a microlithography projection objective.
• the objective according to the invention is also suitable for microscopy or use in inspection systems.
• the lenses are in the entire wavelength range, i. also usable for wavelengths> 193 nm.
• a particularly preferred, but not the exclusive field of application is the use as a microlithography projection objective in
• Microlithography projection exposure equipment in particular for wavelengths ⁇ 193 nm.
• dioptric lenses use refractive elements, for example lens elements to image light from an object plane into an image plane.
• Catalytic lenses use reflective elements, such as mirror elements to image light from an object plane into an image plane, and catadioptric objectives use both refractive and reflective elements to image light from an object plane into an image plane.
• high angles of incidence occur on at least some of the mirrors of the high-aperture projection objective.
• high angles of incidence lead to strong reflection losses and to phases which can not or only with difficulty be corrected, end differences of s- and p-polarized light.
• high incidence angles or very large incidence angle variations occur over the mirror.
• US Pat. No. 6,750,948 B2 proposes a microlithography projection system in which at least one mirror has an opening, so that obscuration of the pupil occurs.
• a disadvantage of this system is that the mirrors of the first sub-objective according to US 2004/0114217 have broken mirrors, i. Mirrors with an opening are.
• a disadvantage of a system with broken mirrors in the first partial objective is that it is unsuitable for large fields as in EUV lithography, since all mirrors are arranged close to the pupil and therefore there is no possibility of correcting field-dependent aberrations such as telecentricity and distortion.
• LEDs are also developed for the UV range, generate so strong chromatic aberrations that they can not be used as a light source in conventional refractive lithography systems.
• Light-emitting diodes so-called LEDs in the blue, in particular in the UV range, emit wavelengths of, for example, 365 nm, 280 nm or 227 nm.
• the bandwidth of these light-emitting diodes is between +/- 20 nm and +/- 50 nm.
• the light output powers are up to 10OmW.
• the object of the invention is therefore to overcome the disadvantages of the prior art.
• a high-aperture objective in particular a projection lens is to be specified, which is characterized on the one hand by low angles of incidence, on the other hand should be given in a particularly preferred embodiment, a sufficient working distance of physically to the image plane nearest mirror.
• a telecentric beam guidance on the image side.
• second aspect of the invention also a
• System can be specified, with which structures smaller than 50 nm can be resolved. This should apply in particular to systems which are operated with wavelengths ⁇ 193 nm, in particular ⁇ 157 nm, very particularly ⁇ 100 nm.
• a system is to be specified, which allows the use of a broadband light source (eg LEDs), or which the use of various discrete Light wavelengths eg at 633nm and 248nm possible.
• a broadband light source eg LEDs
• various discrete Light wavelengths eg at 633nm and 248nm possible.
• the microlithography projection objective according to the invention is preferably subdivided into a first partial objective which has at least one mirror and a second partial objective which has at least two further mirrors.
• an objective in particular a microlithography projection objective having a first partial objective which has at least one mirror and a second partial objective which has a primary concave mirror and a secondary partial objective
• Concave mirror has dissolved, wherein the mirror of the first partial objective has no opening for the passage of a beam tuft, which passes through the projection lens from the object side to the image side.
• at least two mirrors of the second partial objective are designed as concave mirrors, namely as primary and secondary concave mirrors
• a "mirror” is always understood to mean the optically used region of the mirror surface.
• the optically used region is the region onto which the light rays which pass through the objective from the object plane to the image plane impinge, due to the configuration of the two mirrors of the second partial objective as
• the primary concave mirror has a distance from the image plane, which is more than 12 mm, in particular more than 15 mm.
• the distance of the primary concave mirror from the image plane is understood to be the distance of the vertex of the mirror surface of the primary concave mirror from the image plane. Particularly preferably, this distance is more than 12 mm, in particular more than 15 mm, particularly preferably more than 30 mm, in particular more than 60 mm.
• the projection system has a picture-side numerical aperture NA, the NA> 0.4, preferably NA> 0.5, most preferably NA> 0.6, more preferably NA> 0.7.
• the primary concave mirror may be designed as a manganese mirror.
• the incident light beam passes through a lens material, such as CaF 2 at wavelengths of 157 nm or SiO 2 at 193 nm, and is reflected on the back of the lens, which may be provided with a reflective coating. In this way, it is possible to form a very thick and thus stable mirror, which has only a very small distance from the image plane in which the object to be illuminated is arranged.
• the at least one mirror of the first partial objective has a reflective surface, on which the beam tuft, which passes through the microlithography projection objective from the object plane to the image plane, and the reflective surface forms a first off-axis segment.
• the objectives in particular microlithography projection objectives according to the invention, have an axis of symmetry, which is also referred to as an optical axis.
• the mirrors are rotationally symmetrical to the optical axis.
• An off-axis segment or a so-called off-axis segment of a mirror is understood to mean a mirror segment which is only a part of the axis rotationally symmetrical about this axis Mirror surface, namely an off-axis part of the mirror comprises.
• the microlithography In addition to the first partial objective, which designates the so-called field group of the objective, and the second partial objective, which is also referred to as a relay group, in an advantageous embodiment the microlithography
• Projection objective a third partial objective which is formed in the light path from the object plane to the image plane after the first partial objective and before the second partial objective.
• the third partial lens is also referred to as a so-called transfer group.
• a projection lens which is composed of a total of three partial lenses or three sub-groups, the first partial objective, the so-called field group, the object on a first intermediate image.
• the first partial objective lies in that part of the overall objective which has a low aperture
• shading-free beam guidance is also achieved when using off-axis or so-called off-axis mirror segments.
• off-axis segments in the first partial objective field-dependent aberrations such as telecentricity and distortion can be corrected because the off-axis segments can be arranged close to the field.
• an accessible pupil plane can be formed in the first partial objective, which is arranged either directly on a mirror or between two mirrors of the first partial objective and in which an aperture diaphragm and a shading element defining the pupil obscuration can be arranged.
• the arrangement of the shading element for the pupil obscuration in a pupil plane achieves a field-independent pupil obscuration.
• Shading element not arranged in a pupil plane, so would result in a field-dependent pupil obscuration.
• a field dependent pupil obscuration but is unsuitable for the use of the projection objective in the microlithography for lithographic images, as this field-dependent variation of the resolution is generated.
• the first partial objective comprises more than two, namely four mirrors, wherein in particular the mirror sequence concave-convex-convex-concave of the four mirrors of the first partial objective is of particular advantage.
• the mirror sequence of the four mirrors of the first partial objective can also be convex-concave-convex-concave.
• the radius of curvature of the first mirror is chosen to be very large, in particular greater than 10,000 mm.
• the mirror sequences plan-concave-convex-concave or concave-concave-convex-concave are also possible for the four mirrors of the first partial objective.
• the first partial objective may comprise six mirrors. Different mirror sequences are conceivable for the six mirrors of the first partial objective.
• the mirror sequence is convex-concave-convex-concave-concave-convex, in a second embodiment convex-concave-concave-convex-convex-concave, in a third embodiment concave-concave-convex-concave-convex- concave, in a fourth embodiment concave - convex-concave - concave - convex - concave, and in a fifth embodiment concave - convex - concave - convex - convex - concave possible.
• the radius of curvature of the first mirror of the first partial objective is chosen to be very large, preferably greater than 10,000 mm. Therefore, subsequent mirror sequences in the first partial objective are also possible, since the first mirror can be formed either flat or convex or concave: concave - concave - convex - concave - concave - convex plan - concave - convex - concave - condave - convex convex - concave - convex - concave - convex - concave flat - concave - convex - concave - convex - concavex - concave convex - concave - concave Concave - Concave - Concave Plan - Convex - Concave - Concave - Concave - Convex - Concavex - Concavex - Concavex - Concavex
• Object level to reach the image plane second mirror in the first part of the objective it is advantageous to form the second mirror in the first part of the objective in the light path from the object plane to the image plane as a concave mirror.
• the objective in particular the microlithography projection objective, comprises a third partial objective, which is also referred to as a transfer group.
• the third partial objective preferably consists of at least two mirrors, in a particularly advantageous embodiment of exactly two mirrors.
• This third partial objective has the task of transforming the low-aperture objective part into a high-aperture objective part, that is to say the objective of the invention. H. essentially to set the imaging scale or imaging factor. It is particularly advantageous if one of the two mirrors of the transfer group is convex and the other is concave. If the mirrors of the transfer group of the third mirror and the fourth mirror are referred to, this means that preferably either the third mirror is convex and the fourth mirror is concave or the third mirror is concave and the fourth mirror is convex.
• the microlithography projection system is configured such that the first partial objective focuses on the object plane to a first intermediate image, the third
• Partial lens the first intermediate image on a second intermediate image and the second partial objective images the second intermediate image in the image plane.
• the openings ie the mirror bores
• the intermediate images of the system are formed between individual partial objectives in the vicinity of the mirror bores. It is particularly advantageous if the first intermediate image is physically in the vicinity of the fourth mirror and the second intermediate image is physically in the vicinity of the third mirror.
• the distance of the respective intermediate image from the vertex of the mirror surface has a distance measured along the optical axis of less than 1/10 of the overall length of the objective.
• the length of the lens is understood to be the distance along the optical axis from the object plane to the image plane.
• the third partial objective produces the second intermediate image, which is generally inaccessible to the image plane due to the preferred position on the third mirror.
• the second intermediate image is preferably imaged by the second partial objective in the image plane such that an under
• the diameters of the third mirror and the secondary concave mirror are not very different from each other as in US 2004/0114217 A1, but essentially of the same order of magnitude.
• the diameters of the two mirrors differ only by a factor of 2 from each other.
• D1 denotes the diameter of the secondary concave mirror, d2 the diameter of the third mirror, z1 the distance of the second intermediate image from the mirror surface of the secondary concave mirror and z2 the distance of the second intermediate image from the mirror surface of the third mirror.
• the inventors have now found that if this condition is met, the obscuration of the system becomes minimal. In particular, an undesired enlargement of the pupil obscuration can be prevented.
• the two reflective front and rear surfaces of a substrate are used, wherein in the double mirror an aperture opening, for example. In the form of a hole is recessed.
• the two sides of the substrate are coated in such a double mirror respectively on the front and back with a highly reflective layer, for example.
• ⁇ 13 nm comprising 40 layer pairs of Mo / Si.
• the fourth last mirror is the third mirror, and the last mirror in the light path from the object plane to the image plane is the secondary concave mirror.
• Such a double mirror has the advantage that it can be made and taken like a lens.
• An embodiment in the form of two mirrors would also be possible. However, then both mirrors must be made of a material, which has a high rigidity (eg silicon carbide)
• the aperture opening of the double mirror in this case the bore, is of conical configuration.
• a mangin mirror can also be used.
• lower incident angles are achieved on the mirrors by forming the second mirror in the light path from the object plane to the image plane as a concave mirror.
• the aperture stops and the shading apertures of the system are arranged not in one place, but in two mutually conjugate aperture planes, the aperture planes in turn representing conjugate planes to the entrance pupil of the projection objective, i. H. so-called pupil levels are.
• both the shading aperture and the aperture diaphragm By arranging both the shading aperture and the aperture diaphragm away from a mirror, both optical and mechanical advantages result.
• An aperture or obscuration diaphragm arranged directly in front of a mirror will inevitably pass twice from the light beam, so that unavoidable vignetting will occur which will impair the imaging quality.
• an arrangement of an aperture or Obscuration diaphragm close to a mirror difficult because on the one hand the space required to limit each other and narrow and on the other hand, the mechanical position tolerances must be kept very tight. If the obscuration diaphragm is realized by means of an antireflection coating on a mirror-as disclosed in US Pat. No.
• microlithography projection objectives with a second partial objective which comprises two concave mirrors, are indicated, but which have only a first partial objective, which is referred to as a so-called field group.
• the field group comprises only so-called off-axis mirror segments.
• These lenses do not have a third partial lens, i. no transfer group with mirrors having a passage for a bundle of tufts. The advantage of such lenses is that through the
• the effect of the transfer group namely the switching from the low-aperture field group to the high-aperture aperture group, is accomplished by field and aperture group itself.
• the field group comprises six mirrors, the mirror sequence is, for example, concave-concave-convex-concave-convex-concave or concave-convex-concave-convex-convex-concave.
• a lens is specified with which it is possible to resolve structures having a feature size in the range of 50 nm and less at a wavelength ⁇ 193 nm, ie in particular 193 nm, 157 nm or at a wavelength of about 100 nm ,
• This second aspect of the invention is achieved by a system wherein the system is constructed such that the image-side numerical aperture NA is greater than 0.7.
• the numerical aperture is greater than 0.72, preferably greater than 0.80, most preferably 0.90.
• An objective according to the second further aspect of the invention preferably has more than eight mirrors, in particular at least ten mirrors.
• an objective according to the second aspect of the invention may comprise an image field, wherein at least one image field dimension or image field dimension is greater than 1 mm.
• a system with a high numerical aperture is characterized in that the largest angle of incidence of the main beam to a central field point on all mirrors is less than 30 °
• the system comprises two subsystems, a first subsystem and a second subsystem.
• the first subsystem comprises only mirrors without a central opening, which is preferably arranged off-axis to a main axis of the projection lens. These mirrors are therefore formed by so-called off-axis segments.
• the first subsystem is also called a field group.
• the second subsystem comprises at least one mirror with a central opening.
• the second subsystem is also referred to as an aperture group.
• the invention includes the array of eight mirrors subdivided into a first six-mirror sub-lens subsystem and a second two-mirror sub-lens subsystem.
• the mirror sequence of the field group is preferably concave-concave-concave-concave-convex-convex-concave. Because the field group comprises eight mirrors, field-dependent aberrations can be corrected very well.
• the aperture group in the first embodiment according to the further aspect of the invention comprises two concave mirrors.
• the field group comprises six mirrors with the mirror sequence concave-concave-convex-concave-convex-concave.
• the array is divided into a first partial lens subsystem having four mirrors and a second partial objective subsystem having two mirrors.
• the aperture group comprises a first partial objective subsystem consisting of two concave mirrors and a second one
• Partial objective subsystem consisting of two concave mirrors. Overall, a total of three intermediate images are formed in the lens according to the second embodiment.
• the second embodiment is characterized in that a very high aperture at very low angles of incidence is achieved. Thus, the angle of incidence of the main beam is the central field point in the second
• Embodiment according to the further aspect of the invention less than 30 °. Furthermore, the system according to the second embodiment of the second further aspect of the invention is characterized by large drift paths between the mirrors.
• the field group comprises six mirrors.
• the mirror sequence in the field group is: convex-concave-concave-convex-convex-concave.
• the aperture group is also divided into a first partial objective subsystem and a second partial objective subsystem.
• the mirror sequence in the aperture group is: convex-concave-concave-concave.
• the lens has two intermediate images. The lens is characterized in particular by a very high aperture.
• a system with at least eight mirrors wherein the system is constructed such that the image-side numerical aperture NA is greater than 0.5, in particular greater than 0.7, wherein in the beam path between the object plane and image plane maximally an intermediate image is formed.
• the system has two partial lenses and the second partial lens has at least one mirror which has an opening for the passage of a ray bundle.
• these systems are characterized in that the largest angle of incidence of the main beam to a central field point on all mirrors is less than 30 °, preferably less than 26 °.
• the first subsystem comprises only mirrors without a central opening, which is preferably arranged off-axis to a main axis of the projection objective. These mirrors are then formed by so-called off-axis segments.
• the first subsystem is also called a field group.
• the second subsystem preferably comprises at least one mirror with a central opening.
• the second subsystem is also referred to as an aperture group.
• the field group comprises six mirrors with the mirror sequence convex-concave-concave-convex-convex-concave and has a central shading in the pupil, the area is less than 12% of the total illuminated pupil.
• the advantage of this embodiment lies in the very low shading of the pupil.
• Another advantage of this embodiment is that the entrance pupil has a negative cutting width. This makes it possible to dispense with two mirrors in the lighting system, whereby the transmission for the entire system is increased.
• the field group comprises six mirrors with the mirror sequence concave-concave-convex-concave-concave-convex, wherein the radius of curvature of the first mirror is so large that it can alternatively be designed flat or convex.
• the cutting width of the first mirror is so large that it can alternatively be designed flat or convex.
• Entrance pupil is designed positively in this example, so that particularly small angles of incidence on the mirror surfaces in the Feldgrupppe occur, which are ⁇ 26 °.
• a transmissive mask i. H. a transmission mask
• a beam splitter or semitransparent mirror can be installed in the beam path.
• the aperture group in a preferred embodiment comprises two mirrors.
• the first mirror of the aperture group is a convex mirror and the second mirror of the aperture group is a concave mirror.
• exactly one intermediate image is formed between the field group and the aperture group.
• the aperture is in the optical path between the first mirror of the aperture group, i. H. the seventh mirror and the second mirror of the aperture group, d. H. the eighth mirror arranged.
• the aperture diaphragm it is possible to interpret this as an iris diaphragm, since there is enough adjacent space available.
• the aperture can also be arranged in the field group near or on a mirror.
• an illumination system illuminates a structure-carrying mask (reticle), which is imaged by the projection objective onto a photosensitive substrate.
• reticle structure-carrying mask
• Projection exposure systems are well known from the prior art, for example, for the EUV lithography from US 5,212,588, US 5,003,567, US 6,452,661 or US 6,195,201 and for lithography with wavelengths ⁇ 193 nm from US 6,512,641 and EP 1069448.
• double-faceted illumination systems are preferred, in particular those in which the field facets of the field facet mirror have the shape of the field to be illuminated in the reticle plane, ie. H. when to be illuminated annular field in the field facet plane, the field facets are annular.
• a field-shaping mirror is not needed in such a system.
• Microstructured semiconductor devices are fabricated in a variety of unique, very complex process steps.
• An essential process step relates to the exposure of photosensitive substrate (wafers), for example, provided with photoresist silicon substrates.
• the corresponding reticle is imaged by the projection objective onto the wafer.
• the lenses described in the invention, in particular the described projection lenses have taken together the advantages shown in the following section individually or in combination.
• An advantage of the described catoptric projection objectives is their very large image-side numerical aperture.
• the projection lenses may have a large image-side numerical aperture and relatively low angles of incidence of the radiation impinging on the reflective elements of the projection lens. Accordingly, intensity variations of the radiation reflected by the reflective elements can be reduced compared to projection lenses in which the radiation impinges on one or more reflective elements in a wide angular range. The reduced intensity variations cause a better image quality to be achieved. Furthermore, certain have
• Embodiments of the projection lenses shown here a large image-side numerical aperture and a relatively large working distance, which leads to sufficient space z. B. is provided for the wafer days, and the image plane is easily accessible.
• the image side working distance may be 15mm or more.
• the projection objectives are telecentric on the image side.
• the projection objectives may include mirrors having openings for the passage of radiations formed such that only a small amount of radiation is emitted
• Obscurations of the pupil occur. Certain embodiments are characterized by a very large resolution.
• the projection lenses can resolve structures with structure widths ⁇ 50 nm. This high resolution can be achieved in the projection lenses according to the invention together with a high image-side numerical aperture. Preferred are the
• Projection lenses designed for the use of short wavelengths, for example. Wavelengths between 10 nm and 30 nm.
• the projection lenses provide a low aberration image.
• the projection lenses have a wavefront error of 10 m ⁇ or less.
• the distortions are corrected to values better than 1 nm.
• the projection objectives may comprise one or more pupil planes, which may be designed to be accessible for introducing an aperture stop or an obscuration stop or shadowing stop in the pupil plane.
• the projection lenses described herein may be configured for operation at a variety of different wavelengths, for example wavelengths in the visible region of the light or UV wavelengths. Most preferably, the embodiments are designed for operation at EUV wavelengths. In a further embodiment of the invention
• Embodiments may be designed for use at one or more wavelengths or in a wavelength range.
• very low angles can be present at the reticle with a relatively high image-side aperture.
• radiation of the illumination system may impinge on the reticle at angles ⁇ 10 ° or less, for example about 7 °, with respect to the optical axis, the projection objective having a picture-side numerical aperture of 0.4 or more.
• the projection lenses have features that allow for a reduction in the complexity of the lighting system.
• the position of the entrance pupil of the projection objective can lie in the light path in front of the object plane.
• principal rays emanating from different field points are divergent with respect to each other and with respect to the optical axis.
• the projection lenses may have a relatively large workspace close to the position where the optical axis intersects the object plane.
• this allows the arrangement of components, in particular components of the illumination system near the reticle.
• this can be achieved by designing the projection lens so that the mirror that is physically closest to the object plane is positioned relatively far from the optical axis.
• it may be that the beam that travels from the reticle to the first mirror of the projection lens intersects with the beam traveling from the second mirror to the third mirror of the projection lens.
• Fig. 1 a schematic view of a microlithography projection exposure apparatus
• Fig. 1 b beam cone which impinges on an object in an image plane
• FIG. 1c shows a section of a mirror surface onto which a plurality of rays of a radiation passing through the projection objective impinge.
• Fig. 1d Example of a mirror of an opening for the passage of a Beam tuft has
• Fig. 1e Example of a mirror having no opening of a beam tuft.
• Fig. 1f Example of a partial objective in a Meridionalebene
• Fig. 1g Example of an alternative partial objective in a Meridionalebene
• Fig. 1 h partial lens, which consists of mirrors with an opening in one
• Fig. 1 i Alternative example of a partial objective constructed of mirrors comprising an opening in a meridian plane
• Fig. Ij embodiment of a projection lens with Obskurations- or
• Fig. 1 k embodiment of a projection lens with shading in the light path between two mirrors
• Fig. 1 l-m Design of a projection lens with shading in the light path between two mirrors and fastening device
• Fig. 1 n Example of a ring field, as it is formed, for example, in the image plane
• Fig. 1o Definition of the image-side free working distance
• Fig. 1 p embodiment of a projection lens with crossed
• FIG. 19 Illumination system with a microlithography projection objective with obscured pupil.
• FIGS. 1a to 1p general terms used in a variety of embodiments and referring to a variety of embodiments are described in detail with reference to the figures.
• FIG. 1a shows a microlithography projection exposure apparatus 2100.
• the microlithography projection exposure apparatus comprises a light source 2110, an illumination system 2120, a projection objective 2101 as well as a support structure or work surface 2130. Further, a Cartesian Coordinate system shown.
• the radiation of the light source 2110 is supplied to an illumination system 2120.
• the illumination system 2120 influences the radiation emanating from the light source 2110, for example, in which the radiation is homogenized or by directing a radiation beam 2122 of the radiation onto a mask 2140 which is positioned in an object plane 2103.
• the illumination system 2120 influences the radiation emanating from the light source 2110, for example, in which the radiation is homogenized or by directing a radiation beam 2122 of the radiation onto a mask 2140 which is positioned in an object plane 2103.
• Projection objective 2101 images the radiation reflected by the mask 2140 onto a substrate surface 2150 positioned in an image plane 2102.
• the pencil of rays on the image side of the projection objective 2101 is identified by reference numeral 2152.
• the substrate 2150 is supported by a support structure 2130, the support structure 2130 moving the substrate 2150 relative to the projection objective 2101 so that the projection objective 2101 images the mask 2140 onto different areas of the substrate 2150.
• the projection objective 2101 comprises an optical axis 2105. As shown in FIG. 1 a, the projection objective 2101 images part of the mask 2140 which does not encompass the optical axis of the projection objective 2101 into an image plane 2102. In alternative embodiments, not shown, objects that lie on the optical axis HA of the projection objective can also be imaged into the image plane 2102.
• the light source 2110 is selected to provide electromagnetic radiation at an operating wavelength ⁇ at which the microlithography projection exposure apparatus 2100 is operated.
• the light source 2110 is a laser light source, such as a laser plasma source for emission of EUV radiation, or a KrF laser for wavelengths at 248 nm or an ArF laser at 193 nm.
• light sources other than those described herein can be used
• Laser light sources such as light-emitting diodes (LED), emit the radiation in the blue or UV range of the electromagnetic spectrum, for example at 365 nm, 280 nm or 227 nm.
• LED light-emitting diodes
• the operating wavelength ⁇ of the microlithography projection exposure apparatus is in the ultraviolet or extreme ultraviolet (EUV) region of the electromagnetic spectrum.
• the operating wavelength can be 400 nm or less, 300 nm or less, in particular 200 nm or less, very particularly 100 nm or less.
• the operating wavelength can be in the range of 193 nm, preferably in the range of 157 nm, very particularly preferably in the EUV wavelength range, in particular in the region of 13 nm.
• the illumination system 2120 includes optical components that provide a collimated beam having a substantially homogeneous intensity profile
• the lighting system 2120 further includes optics to direct the beam tuft 2122 onto the mask 2140.
• the illumination system 2120 further includes components that provide a particular polarization profile of the beam.
• the image plane 2103 has a distance L to the object plane 2102, which is also referred to as the overall length BL of the projection objective 2101. In general, this length depends on the specific configuration of the projection objective 2101 and the wavelength at which the microlithography projection exposure apparatus 2100 is operated. In the described embodiments, the overall length is in the range of one meter to about three meters, preferably in the range of about 1, 5 m to 2.5 m.
• the overall length is less than 2 m, for example. Less than 1, 9 m, preferably less than 1, 8 m, more preferably less than 1, 7 m, more preferably less than 1, 6 m, particularly preferably less than 1, 5 m.
• the projection lens 2101 has an imaging factor related to the ratio of the dimensions of the field in the object plane 2103 to the corresponding dimensions of the imaged field in the image plane 2102.
• the projection lenses used in lithography equipment are reduction projection lenses, i. that the dimensions of the image are smaller than those of the object.
• the projection lens 2101 may generate a field in the image plane 2102 whose dimensions are a factor of 2x or more, preferably 3x or more, more preferably 4x or more, most preferably 5x or more, particularly preferably 6x or more, preferably 7x or more preferably 8x or more, more preferably 9x or more, most preferably 10x or more, compared with the dimensions in the object plane 2103.
• projection lenses may also be developed that have an enlarged image or image of the same size as the object provide.
• the marginal rays 2152 of the light pencil which depict the objects in the image plane 2102 are shown.
• the marginal rays 2152 define a beam cone.
• the angle of the beam cone is related to the image-side numerical aperture (NA) of the projection lens 2101.
• NA image-side numerical aperture
• the image-side numerical aperture can be expressed as
• ⁇ max is the angle defined by the marginal rays of the projection lens 2101.
• projection objectives 2101 have a relatively high image-side numerical aperture NA.
• the image-side numerical aperture NA of the projection objective 2101 is more than 0.4, in particular more than 0.45, in particular more than 0.5, in particular more than 0.55, in particular more than 0.6, in particular more than 0 , 65, in particular more than 0.7, in particular more than 0.75, in particular more than 0.8, in particular more than 0.85, in particular more than 0.9.
• the resolution of the projection lens 2101 varies depending on the wavelength ⁇ and the image-side numerical aperture NA.
• the resolution of a projection lens can be related to the wavelength and to the image-side numerical aperture by the following formula
• R denotes the minimum dimension of the projection objective that can be resolved
• k is a dimensionless one
• the process factor k varies depending on various factors, for example the polarization properties of the resist material. Typically, k ranges from 0.4 to 0.8, but k may also be below 0.4 and greater than 0.8, for specific applications.
• the projection objective 2101 has a relatively high resolution, ie, the value of R is relatively small.
• R may have a value of 150 nm or less, preferably 130 nm or less, even more preferably 100 nm or less, particularly preferably 75 nm or less, very preferably 1 50 nm or less, preferably 40 nm or less, especially preferably 35 nm or less, more preferably 32 nm or less, in particular 30 nm or less, preferably 28 nm or less, in particular 25 nm or less, particularly preferably 22 nm or less, preferably 20 nm or less, particularly preferably 18 nm or less, in particular 17 nm or less, very preferably 16 nm or less , in particular 15 nm or less, particularly preferably 14 nm or less, very preferably 13 nm or less, in particular 12 nm or less, preferably 11 nm or less, particularly preferably 10 nm or less.
• the quality of an image formed by the projection lens 2001 can be quantified in various ways.
• images may be characterized or quantified based on the measured or calculated deviations of the image from ideal conditions that can be achieved with Gaussian optics. These deviations are generally known as aberrations.
• One measure used to quantify the deviation of a wavefront from the ideal or desired shape is the "root-mean-square" wavefront error, the so-called RMS value W RM s-W RM s, for example. as defined in "Handbook of optics", Vol. 1, 2 nd , edited by Michael Bass (McGraw Hill), Inc. 1995 on page 35.3.
• W RM s-W RM s the so-called RMS value
• the projection lens 2101 has very small values for W RM s of the image in the image plane 2102. For example. can one
• Projection lens 2101 has a W RM s value of about 0.1 - ⁇ or less, in particular less than 0.07 ⁇ , particularly preferably less than 0.06 ⁇ , in particular less than 0.05 ⁇ , preferably less than 0.045 - ⁇ , in particular less than 0.04- ⁇ , very particularly preferably less than 0.035- ⁇ , particularly preferably less than 0.03- ⁇ , particularly preferably less than 0.025- ⁇ , particularly preferably less than 0.02- ⁇ , in particular preferably less than 0.15- ⁇ , more preferably less than 0.01 - ⁇ .
• Another measure that can be used to evaluate the quality of an image is the field curvature or field curvature, the so-called field curvature.
• the field curvature is defined as the peak-to-valley value of the axial focal plane position as a function of the field point.
• the projection objective 2101 has a relatively small field curvature for images in the image plane 2102.
• the projection objective 2101 has an image-side field curvature of less than 20 nm, preferably less than 15 nm, more preferably less than 12 nm, more preferably less than 10 nm, most preferably less than 9 nm, preferably less than 8 nm, preferably less than 7 nm, more preferably less than 6 nm, more preferably less than 5 nm, most preferably less than 4 nm, more preferably less than 3 nm, preferably less than 2 nm, most preferably less than 1 nm.
• the distortion is defined as the maximum absolute value of the field-point-dependent storage of the pixel from the ideal pixel position in the image plane.
• the projection objective has a relatively small distortion of 10 nm or less, preferably 9 nm or less, more preferably 8 nm or less, particularly preferably 7 nm or less, most preferably 6 nm or less, particularly preferably 5 nm or less, in particular 4 nm or less, preferably 3 nm or less, very preferably 2 nm, preferably 1 nm or less.
• the projection objective 2101 comprises a plurality of mirrors arranged such that the radiation passing from a mask 2140 to a substrate 2150 is reflected such that an image of the mask 2140 on the surface of the substrate 2150 is formed.
• a projection lens Specific embodiments of a projection lens are as described in the following description educated. Generally speaking, the number, size and structure of the mirrors are determined by the desired optical properties of the projection objective 2101 and the physical constraints of the projection exposure apparatus 2100.
• the number of mirrors in the projection lens 2101 may vary. Typically, the number of mirrors is linked to different requirements for the optical properties of the objective.
• the projection lens 2101 has at least four mirrors, preferably at least five mirrors, more preferably at least six mirrors, more preferably at least seven mirrors, most preferably at least eight mirrors, preferably at least nine mirrors, more preferably at least ten mirrors, most preferably at least eleven mirrors, more preferably at least twelve mirrors.
• the projection objective 2101 in which mirrors of the objective are arranged between the object plane and the image plane, has an even number of mirrors, for example four mirrors, six mirrors, eight mirrors or even ten mirrors.
• the projection objective 2101 generally includes one or more mirrors with positive optical power. In other words, this means that the reflecting portion of the mirror, ie the effective area of the mirror, has a concave surface and is accordingly called a concave mirror or concave mirror.
• the projection objective 2101 may comprise two or more, for example, three or more, in particular four or more, very particularly five or more, in particular six or more concave mirrors.
• the projection lens 2101 may also include one or more mirrors having negative optical power. This means that one or more of the mirrors have a reflective section, ie a useful area with a convex surface. Such mirrors are also referred to as convex mirrors or convex mirrors.
• the projection lens 2101 have two or more, in particular three or more, especially four or more, in particular five or more, especially six or more convex mirror.
• the mirrors are in such a way
• Projection lenses 2101 arranged that the radiation emanating from the object plane 2103, one or more intermediate images formed.
• Embodiments of the invention have one or more intermediate images and comprise two or more pupil planes.
• the preferred embodiments have one or more intermediate images and comprise two or more pupil planes.
• Embodiment is arranged at least in one of these pupil planes physically accessible an aperture diaphragm.
• the mirrors are designed such that a large portion of the light of the operating wavelength ⁇ of the projection lens, which under a
• the mirrors can be designed such that they have, for example, more than 50%, preferably more than 60%, very preferably more than 70%, particularly preferably more than 80%, very particularly preferably more than 90% of the radiation incident on the surface a wavelength ⁇ are reflected.
• the mirrors include a multilayer stack, called a multilayer stack, of layers of different material, the stack being configured to substantially reflect radiation of wavelength ⁇ incident on the surface.
• a film of the stack has an optical thickness of about -.
• Stacks may comprise 20 or more, preferably 30 or more, more preferably 40 or more, most preferably 50 or more layers.
• the material chosen to form the multi-layer stacks is selected from the materials suitable for the operating wavelength ⁇ of the microlithography equipment.
• the multiple-layer system consists of alternating multiple layers of molybdenum and silicon or molybdenum and beryllium to form mirrors that reflect radiation in the wavelength range of 10 nm to 30 nm, for example at a wavelength ⁇ of 13 nm or 11 nm.
• the mirrors are made of quartz glass coated with a single layer of aluminum. This, in turn, is overcoated, that is to say overcoated with dielectric layers comprising materials such as MgF 2 , LaF 2 , Al 2 O 3 , for example for wavelengths of approximately 193 nm.
• the proportion of radiation reflected from a mirror varies as a function of the angle of incidence of the radiation on the mirror surface. Since the imaging radiation propagates through a catoptric projection lens along a variety of different paths, the angle of incidence of the radiation on each mirror can vary. This is shown in FIG. 1c, which shows part of a mirror 2300 in meridional section, that is to say in the meridional plane.
• the meridional plane is a plane of the projection lens that includes the optical axis.
• the mirror 2300 includes a concave reflective mirror surface 2301.
• the imaging radiation impinging on the surface 2301 along different paths includes, for example, the paths represented by the beams 2310, 2320, 2330.
• the beams 2310, 2320, and 2330 are incident on a part of the mirror surface 2301.
• the normal to the surface of the mirror are different in this area of the mirror surface 2301.
• the direction of the surface normals in this area are represented by the straight lines 2311, 2321 and 2331, which are corresponding to the beams 2310, 2320 and 2330.
• the rays 2310, 2320, and 2330 strike the surface at the angles ⁇ 2 3io, ⁇ 2320, and ⁇ 23 3o.
• the angles of incidence of the imaging rays can be represented in a variety of ways.
• One possible representation is the maximum angle of the rays impinging on each mirror in the meridional section of the projection objective 2101. This maximum Angle is denoted by ⁇ max .
• the angle ⁇ max of different mirrors of the projection lens 2101 may vary.
• the maximum value ⁇ m a ⁇ (max) for all mirrors of the projection objective 2101 is 75 ° or less, preferably 70 ° or less, more preferably 65 ° or less, more preferably 60 ° or less, preferably 55 ° or less, in particular 50 ° or less, in particular 45 ° or less.
• the maximum angle ⁇ ma ⁇ (max) is relatively small.
• the maximum angle ⁇ m ax (max) 40 ° or less, preferably 35 ° or less, more preferably 30 ° or less, in particular 25 ° or less, particularly preferably 20 ° or less, in particular 15 ° or less, in particular 13 ° or less, more preferably 10 ° or less.
• ⁇ CR angle of incidence of the main ray of the central field point of the field to be illuminated in the object plane on each mirror in the meridional section.
• ⁇ CR main beam angle
• ⁇ cR (max) in the projection lens can be defined as the maximum principal ray angle of the central field point.
• This angle ⁇ c R ( m a x) can be relatively low, for example, the maximum angle ⁇ c R ( m a x ) in the projection lens less than 35 °, preferably less than 30 °, more preferably less than 25 °, in particular less than 15 °, in particular less than 13 °, particularly preferably less than 10 °, preferably less than 8 ° or very preferably less than 5 °.
• Each mirror in the projection objective 2101 may further be characterized by a range of angles of incidence in the meridonal section of the projection objective 2101.
• the range in which the angle ⁇ varies on each mirror is referred to as ⁇ .
• ⁇ is defined by the difference between an angle ⁇ ( max ) and ⁇ (m j n ), where ⁇ ( m j n) is the minimum angle of incidence of the imaging rays on a mirror surface in the meridional section of the projection objective 2101 and ⁇ ( maX ) is the maximum value of the incident imaging rays on a mirror surface, as previously defined.
• the range ⁇ varies for each mirror in the projection lens 2101.
• ⁇ may be relatively small.
• ⁇ may be less than 10 °, preferably less than 8 °, particularly preferably less than 5 °, very preferably less than 3 °, in particular less than 2 °.
• ⁇ may be relatively large.
• ⁇ may be 20 ° or more, in particular 25 ° or more, particularly preferably 30 ° or more, particularly preferably 35 ° or more, very particularly 40 ° or more.
• the maximum value for ⁇ , the value ⁇ max, the maximum value of the angular variation on a mirror for all mirrors in the projection lens 2101 be relatively low.
• the value ⁇ max may be less than 25 °, in particular less than 20 °, very particularly less than 15 °, in particular less than 12 °, in particular less than 10 °, in particular less than 8 °, in particular less than 7 ° less than 6 °, more preferably less than 5 °, most preferably less than 4 °.
• catoptric projection lenses are designed to take into account the obscuration of the light path caused by the reflective elements, as opposed to transmissive elements used in dioptric systems.
• the mirrors are configured and arranged so that rays propagate through the projection lens in a light path through a transmissive
• the mirrors in a projection lens 2101 can therefore be divided into two groups:
• Mirrors with no openings An example of a mirror 2600 comprising an opening for the passage of a jet tuft is shown in Figure 1d.
• the mirror 2600 includes an aperture 2610.
• the mirror 2600 may be disposed in the projection lens 2101 such that the optical axis 2105 intersects the aperture 2610.
• the mirror 2600 is circular in shape with a diameter D. In general, D is determined by the design of the projection lens 2101.
• D is 1500 mm or less, preferably 1400 mm or less, more preferably 1300 mm or less, especially 1200 mm or less, very particularly 1100 mm or less, most preferably 1000 mm or less, particularly preferably 900 mm or less, very particularly preferably 800 mm or less, very preferably 700 mm or less, in particular 600 mm or less, preferably 500 mm or less, very particularly 400 mm or less, very preferably 300 mm or less, in particular 200 mm or less, very preferably 100 mm or less.
• the mirrors of the projection lens 2101 may include an aperture of circular or non-circular shape.
• Mirrors which are not of circular shape may have a maximum dimension which is less than 1500 mm, preferably less than 1400 mm, in particular less than 1300 mm, preferably less than 1200 mm, in particular less than 1100 mm, preferably less than 1000 mm , in particular less than 900 mm, preferably less than 800 mm, in particular less than 700 mm, preferably less than 600 mm, in particular less than 500 mm, preferably less than 400 mm, in particular less than 300 mm, preferably less than 200 mm, in particular less than 100 mm.
• the opening 2610 is, for example, circular with a diameter Do. Th depends on the design of the projection objective 2101 and is generally dimensioned to provide a sufficiently large aperture for the passage of radiation from the object plane 2103 to the image plane 2102.
• the opening can also be non-circular. Examples of non-circular openings include polygonal openings such as a square opening, a rectangular opening, a hexagonal opening, an octagonal opening and non-circular arcuate openings, for example elliptical openings or irregular curved openings.
• Openings of non-circular shape may have a maximum diameter of 0.75D or less, more preferably 0.5D or less, preferably 0.4D or less, more preferably 0.3D or less, preferably 0.2D or less, especially 0.1 D or less, preferably 0.05 D or less.
• mirrors may include non-circular openings having a maximum dimension of about 50 mm or less, preferably 45 mm or less, more preferably 40 mm or less, preferably 35 mm or less, in particular 30 mm or less, preferably 25 mm or less , in particular 20 mm or less, preferably 15 mm or less, in particular 10 mm or less, in particular 5 mm or less.
• the apertures may be formed in different mirrors of the same shape or different shape. Furthermore, the openings for the passage of radiation in different mirrors may have the same dimension or different dimensions.
• FIG. 1e An example of a mirror 2660 that does not include an aperture is shown in FIG. 1e.
• the mirror 2660 has the shape of a ring segment.
• the mirror 2660 corresponds in shape to a segment of a circular mirror 2670 having a diameter D.
• the mirror 2660 has a maximum dimension in the x direction given by M x .
• M x may be 1500 mm or less, preferably 1400 mm or less, in particular 1300 mm or less, in particular 1200 mm or less, preferably 1100 mm or less, in particular 1000 mm or less, preferably 900 mm or less, in particular 800 mm or less, preferably 700 mm or less, in particular 600 mm or less, in particular 500 mm or less, preferably 400 mm or less, in particular 300 mm or less, preferably 200 mm or less, in particular 100 mm or less.
• the mirror 2660 is symmetric with respect to the meridian 2675.
• the mirror 2660 has a dimension M x along the meridian 2675.
• M y may be less than or greater than M x .
• M x is in the range of 0.1 M x , preferably 0.2 M x or more, in particular 0.3 M x or more, in particular 0.4 M x or more, preferably 0.5 M x or more, in particular 0, 6 M x or more, preferably 0.7 or more, in particular 0.8 M x or more, very preferably 0.9 M x or more.
• M y may be 1, 1 M x or more, preferably 1, 5 M x or more, or in the range of 2 M x 10 M x .
• M y may be about 1000 mm or less, preferably 900 mm or less, more preferably 800 mm or less, preferably 700 mm or less, more preferably 600 mm or less, preferably 500 mm or less, more preferably 400 mm or less, especially 300 mm or less , in particular 200 mm or less, preferably 100 mm or less.
• Mirrors that do not include an aperture may be arranged so that the optical axis 2105 intersects the mirror or else that the optical axis 2105 does not intersect the mirror.
• the projection lens 2100 can include mirrors of different shapes and sizes, depending on the design.
• the maximum dimension of each mirror of the projection lens may be 1500 mm or less, preferably 1400 mm or less, in particular 1300 mm or less, preferably 1200 mm or less, in particular 1100 mm or less, especially 1000 mm or less, in particular 900 mm or less, preferably 800 mm or less, in particular 700 mm or less.
• the projection lens 2101 includes a group of mirrors, for example, 2 or more mirrors, 3 or more mirrors, 4 or more mirrors, 5 or more mirrors, 6 or more mirrors that have no opening and that are arranged to be one Mapping object, for example, in an image plane 2102 or in an intermediate image plane.
• the projection objective 2101 comprises groups or groups of mirrors
• the group of mirrors is referred to as a partial objective or subsystem.
• the projection lens 2101 may include more than one sub-objective.
• the projection objective may comprise two partial objectives, three partial objectives, four partial objectives or more than four partial objectives.
• An example of a partial objective is the partial objective 2400 shown in FIG. 1f.
• the partial objective 2400 comprises mirrors 2410, 2420, 2430 and 2440 arranged in such a way as to image the radiation from an object plane 2403, which corresponds to the object plane 2103 or an intermediate image plane, into an image plane 2402 corresponding to the image plane 2102 or an intermediate image plane.
• the reflective surfaces of the mirrors 2410, 2420, 2430, and 2440 are portions of axially symmetric surfaces in which the remainder of the mirror surface has been removed to provide a path for the imaging radiation.
• the parts of the mirrors are the portions of the mirror surface to which radiation impinges. They are also referred to as useful areas.
• the first mirror in the path of the radiation which passes through the projection lens, ie in the beam path or light path, is present mirror 2420 which is closest to, ie in the vicinity of the plane 2402, while the second mirror in the light path, ie Beam path of the mirror 2410 is the closest to, that is, located near the plane 2403.
• the mirrors forming sub-objective 2400, ie mirrors 2460, 2470, 2480 and 2490, are portions of axially symmetric surfaces in which the remainder of the mirror surface would be removed to provide an optical path for the imaging beam path (s), ie In the present case, only the areas of the mirrors are shown that reflect light, the so-called. Nutz Schemee.
• the third mirror in the beam path, the mirror 2480 is closest to the plane 2452, whereas the second mirror in the beam path or the light path of the mirror 2460 is closest to the plane 2403.
• a partial objective may also be formed from mirrors that include an aperture.
• a partial objective 2500 is shown that consists of mirrors 2510, 2520 in which the mirror 2510 has an opening 2511.
• the partial objective 2500 is constructed in such a way that it images rays into an image plane 2502, which may correspond, for example, to the image plane 2102 or an intermediate image plane.
• FIG. 1 i shows another example of a partial objective constructed on mirrors which comprise an opening.
• This partial objective is referred to as partial objective 2550.
• the partial objective 2550 comprises mirrors 2560 and 2570.
• the mirror 2560 comprises an opening 2561 and mirror 2570 comprises an opening 2571.
• the partial objective 2550 is designed such that it images radiation or light into an image plane 2552, the image plane forming the image plane Image plane 2102 or an intermediate image plane corresponds. Partial lenses that use mirrors that have an aperture cause part of the pupil of the partial objective to obscure. Accordingly, embodiments of a projection lens 2101 having such a partial objective have an obscured pupil.
• the extent to which the pupil of the projection objective 2101 is obscured can be characterized by the value R O bs, which indicates the proportion of the aperture radius of the projection objective 2101 that is obscured in the pupil plane in a meridional section or in the meridional plane of the projection objective 2101 , Due to the rotational symmetry of the system with respect to the optical axis, it is sufficient to calculate the obscuration radius in the meridional plane.
• the projection objective 2100 may have a very low pupil obscuration.
• R Obs may be 30% or less, preferably 25% or less, more preferably 22% or less, preferably 20% or less, more preferably 18% or less, preferably 15% or less, more preferably 12% or less preferably 10% or less of Aperturradius amount.
• the projection lens 2101 includes one or more pupil planes that are physically accessible to.
• Light obscuring element z. B. to arrange a shading diaphragm substantially in the pupil plane, wherein the pupil plane intersects the optical axis 2105.
• An arrangement of an obscuration diaphragm or a shading diaphragm in a pupil position can lead to a field-independent obscuration of the pupil.
• the shading diaphragms are preferably formed of a material or consist of a coating which does not reflect radiation at the operating wavelength ⁇ , that is to say the coating. H.
• the material absorbs incident radiation
• the shading diaphragm is designed such that no scattered radiation enters the system.
• a mirror 2910 is shown which is disposed substantially in a pupil plane of the projection lens 2101 and has an obscuration aperture 2912 on the mirror surface.
• the obscuration diaphragm 2912 can, for example, consist of a non-reflective coating for radiation at a wavelength ⁇ .
• the obscuration stop 2912 blocks radiation propagating along certain beam paths. This is illustrated in Fig. 1j by the rays 2921, 2922 and 2923. Rays 2921 and 2923 intersect the reflective portion of mirror 2910, whereas beam 2922 intersects shading panel 2912. Accordingly, by the mirror 2910, radiation propagating along the path 2921 and 2923 is incident on an im
• the obscuration stop may be disposed between the mirrors in the projection lens 2101.
• an obscuration stop may be placed in a pupil plane that does not coincide with planes of other mirrors arranged in the projection objective.
• a shading shutter 2926 is placed between the mirrors 2910 and 2920 to block radiation propagating along certain beam paths between the mirrors.
• the obscuration orifice may be placed with the aid of an auxiliary beam 2928 that passes through an opening 2924 of the mirror.
• FIG. 11 to 1 m Another type of attachment is indicated in Figures 11 to 1 m.
• an obscuration stop 2930 is placed between the mirrors 2910 and 2920 with the obscuration stop being held by a retainer ring 2932 whose inner diameter is larger than the aperture of the projection objective in the pupil plane in which the obscuration stop 2930 is located.
• the obscuration shutter 2930 is held on an annular frame member 2932 by means of radial suspensions 2934.
• the suspensions 2934 are designed to block non-significant radiation or light.
• a shading stop which is arranged substantially in a pupil plane, can be removed or exchanged with another shading stop without having to exchange a mirror of the projection objective.
• the obscuration apertures may be disposed on transmissive optical elements.
• transmissive optical elements For example, at operating wavelengths where materials exist that are sufficiently transmissive and have sufficient mechanical strength, an obscuration stop can be held on a transmissive flat element.
• the shading apertures can be realized by coating or placing an obscuration stop on a flat glass element of sufficient size that the flat glass segments are held by the body of the objective 2101.
• Obscuration apertures can be used in embodiments in which at least one mirror of the projection objective 2101 has an opening for the passage of radiation.
• the size of the obscuration apertures may vary. In certain embodiments, the
• Obscuration diaphragm is selected such that it has the smallest possible size that must be provided in order to provide a substantially field-independent obscuration of the exit pupil of the projection objective.
• the obscuration shutter may have a radial dimension of about 60% or less, more preferably 55% or less, more preferably 50% or less, more preferably 45% or less, most preferably 40% or less, in particular 35% or less, in particular 30% or less, in particular 25% or less, especially 20% or less of the radius of the pupil aperture.
• the shape of the field of the projection lens 2101 may vary.
• the field may have an arcuate shape, for example, the shape of a segment of a ring, a so-called ring field.
• a projection lens may have the partial lenses formed of mirrors without an aperture, such as the partial lenses 2400 and 2450 described above, in the form of a ring field.
• FIG. 1f shows a ring segment 2700 or ring field. This ring segment 2700 can be characterized by an x-dimension D x , a y-dimension D y and a radial dimension D r .
• D x and D y correspond to the dimension of the field or to the dimension of the field along the x-direction and the y-direction. These quantities are given in the following description.
• D r corresponds to the ring radius measured from the optical axis 2105 to the inner boundary of the field 2700.
• the ring field segment 2700 is symmetrical with respect to the plane parallel to the yz plane, as indicated by the line 2710.
• the size of D x , D y and D r is variable and depends on the design of the projection lens 2101.
• D x is greater than D y .
• the relative size of the field dimensions D x , D y, and D r in the object plane 2103 and the image plane 2102 vary depending on the magnification or reduction of the projection lens 2101. In some embodiments, D x in the image plane 2103 is relatively large.
• D x in the image plane 2101 may be greater than 1 mm, preferably greater than 3 mm, in particular greater than 4 mm, preferably greater than 5 mm, in particular greater than 6 mm, in particular greater than 7 mm, preferably greater than 8 mm, in particular greater than 9 mm, preferably greater than 10 mm, in particular greater than 11 mm, preferably greater than 12 mm, in particular greater than 13 mm, preferably greater than 14 mm, in particular greater than 15 mm, preferably greater than 18 mm, in particular greater than 20 mm, preferably larger than 25 mm.
• D y in the image plane 2102 can be in the range of 0.5 mm to 5 mm, for example up to 1 mm, preferably up to 2 mm, in particular up to 3 mm, very particularly preferably up to 4 mm.
• D r in the image plane 2102 is in the range of 10 mm to 50 mm.
• D r may be, for example, 15 mm or more, for example 20 mm or more, in particular 25 mm or more, preferably 30 mm or more in the image plane 2102.
• the central field point 2705 for the ring field 2700 is shown.
• the projection objective 2101 can have a maximum field dimension or field dimension of more than 1 mm, in particular more than 3 mm, preferably more than 4 mm, in particular more than 5 mm, preferably more than 6 mm, in particular more than 7 mm. preferably more than 8 mm, in particular more than 9 mm, preferably more than 10 mm, in particular more than 11 mm, preferably more than 12 mm, in particular more than 13 mm, preferably more than 14 mm, in particular more than 15 mm, preferably more than 18 mm, in particular more than 20 mm or more than 25 mm in the image plane 2102 amount.
• the embodiment of the projection lens 2101 has a relatively large image-side free working distance.
• the image-side free working distance refers to the shortest distance between the image plane 2102 and the mirror surface of the mirror, which is arranged geometrically closest to the image plane 2102. This is shown in FIG. 10, which shows a mirror 2810, which is arranged geometrically closest to the image plane 2102. The radiation is reflected by the surface 2811 onto the mirror 2810.
• the image-side free working distance refers to the shortest distance between the image plane 2102 and the mirror surface of the mirror, which is arranged geometrically closest to the image plane 2102. This is shown in FIG. 10, which shows a mirror 2810, which is arranged geometrically closest to the image plane 2102. The radiation is reflected by the surface 2811 onto the mirror 2810.
• the image-side free working distance refers to the shortest distance between the image plane 2102 and the mirror surface of the mirror, which is arranged geometrically closest to the image plane 2102. This is shown in FIG. 10, which shows a mirror 2810, which is arranged
• D w Working distance is denoted by D w .
• D w is 25 mm or more, preferably 30 mm or more, in particular 35 mm or more, preferably 40 mm or more, in particular 45 mm or more, preferably 50 mm or more, in particular 55 mm or more, preferably 60 mm or more, especially 65 mm or more.
• a relatively large working distance is desirable because it allows the surface of the substrate 2150 to be in the Image plane 2102 can be arranged without the one side of the mirror 2810, which is indicative of the image plane 2102, is touched.
• the object-side free working distance refers to the shortest of the distance between the object plane 2103 and the plane of the reflective side of the mirror in the projection lens 2101, which is geometrically located closest to the object plane 2103.
• the projection lens 2101 has a large object-side free working distance.
• the projection lens 2101 may have an object-side free working distance of 50 mm or more, preferably 100 mm or more, more preferably 150 mm or more, preferably 200 mm or more, more preferably 250 mm or more, preferably 300 mm or more, especially 350 mm or more , in particular 400 mm or more, preferably 450 mm or more, preferably 500 mm or more, in particular 550 mm or more, preferably 600 mm or more, in particular 650 mm or more, preferably 700 mm or more, preferably 750 mm or more, in particular 800 mm or more, preferably 850 mm or, in particular 900 mm or more, in particular 950 mm or more, in particular 1000 mm or more.
• a relatively large object-side free working distance may be advantageous in embodiments in which the space between the projection objective 2101 and the object plane 2103 must be accessible.
• the mask 2140 is reflective, it is necessary to illuminate the mask from the side facing the objective 2101. Therefore, there should be enough space between the projection lens 2101 and the object plane 2103 to illuminate the mask by the illumination system 2120 at a certain illumination angle.
• a large object-side free working distance allows flexibility in the design of the remainder of the microlithography projection objective, for example, by providing sufficient space for attaching other components of the projection objective 2101 and the support structure for the mask 2140.
• the mirror that is closest to the object plane 2103 is positioned to be a long distance from the optical axis 2105.
• FIG. 1 p Such a system is shown in Figure 1 p.
• the system shown in FIG. 1 p comprises four mirrors 2941 to 2944, wherein mirror 2941 is arranged closest to the object plane 2103.
• the minimum distance between the mirror 2941 and the optical axis 2105 is the distance 2946.
• the distance 2946 may be 50 mm or more, preferably 60 mm or more, in particular 70 mm or more, very particularly 80 mm or more, in particular 90 mm or more, very particularly 100 mm or more, in particular 110 mm or more, especially 120 mm or more, in particular 130 mm or more, very particularly 140 mm or more, in particular 150 mm or more, in particular 160 mm or more, in particular 170 mm or more, in particular 180 mm or more, in particular 190 mm or more, in particular 200 mm or more, in particular 210 mm or more, in particular 220 mm or more, in particular 230 mm or more, in particular 240 mm or more, in particular 250 mm or more, in particular 260 mm or more, in particular 270 mm or more, in particular 280 mm or more, especially 290 mm or more, more preferably 300 mm or more.
• the distance to the optical axis 2946 is relatively large, as this provides a very large space near the location where the optical axis 2105 intersects the object plane 2103.
• This space can be used to arrange other components of the exposure system or of the lithographic tool, such as, for example, one or more optical components of the illumination system, for example a gracing-incidence mirror, a so-called reflective gracing-incidence element.
• Projection lens are shown, following the light path 2947.
• the rays intersect or hit the mirrors in the following order: mirror 2942, mirror 2941, mirror 2943 and mirror 2944.
• the light path 2947 intersects with itself in the meridional plane between the mirrors 2941 and 2943 before being reflected at the mirror 2942.
• the projection lens 2101 is configured such that
• Principal rays from the reticle 2140 either converge to or diverge from or parallel to the optical axis 2105.
• the position of the entrance pupil of the projection objective 2101 with respect to the object plane 2103 may vary depending on the design of the projection objective.
• the object plane 2103 lies between the projection lens 2101 and the entrance pupil of the projection objective 2101.
• the entrance pupil may be positioned between the object plane 2103 and the projection objective 2101.
• the illumination system 2120 may be arranged such that the exit pupil of the illumination system is arranged substantially at the location of the entrance pupil of the projection objective 2101.
• the illumination system 2120 includes a telescope system that projects the exit pupil of the illumination system to the location of the entrance pupil of the projection objective 2101.
• the exit pupil of the illumination system 2120 is placed in the area of the entrance pupil of the projection objective 2101, without a telescope system being present in the illumination system. For example.
• Illumination system 2120 with the entrance pupil of the projection objective, without the need for a telescope system in the illumination system.
• the projection lens 2101 can be designed using commercially available optical design programs such as ZEMAX, OSLO, Code V. Starting with the definition of the wavelength, the field size and the numerical aperture, the optical properties can be optimized are required for a projection lens, such as the wavefront error, the telecentricity, the uniformity and the distortion.
• optical design programs such as ZEMAX, OSLO, Code V.
• the magnification is sixfold, i. the image is 6 times smaller in the image plane than the object and the resolution is 15 nm.
• the image-side WRMS 0.024 ⁇ and the image field curvature, ie the field curvature 3 nm.
• the overall length of the system is 1745 mm.
• the projection objective according to the invention comprises three partial objectives, the first partial objective 100, the second partial objective 200 and the third partial objective 300.
• the first partial objective comprises a total of four mirrors, S1, S2, S5 and S6. Seen in the light path from the object plane 10 to the image plane 20, the mirror S1 is a concave mirror, the mirror S2 is a convex mirror, the seventh mirror S5 is a convex mirror, and the mirror S6 is a concave mirror.
• the imaging factor of the first partial lens is 1.77x.
• An aperture stop B is arranged on the mirror S5.
• the object plane in which, for example, the reticle comes to rest is denoted by 10.
• the optical axis about which the individual mirror segments are rotationally symmetric is designated HA and the total length of the system from the object plane 10 to the image plane 20, which is also referred to as the overall length, is BL.
• the first partial objective is also referred to as a field group and comprises at least two mirrors, the mirror S1 and the mirror S2.
• Mirror S1 and mirror S2 are like Fig. 1 shows off-axis mirror segments so-called off-axis mirror segments that allow the correction of field-dependent aberrations.
• the first partial objective 100 is followed by a transfer group, referred to herein as the third partial objective 300, comprising two mirrors, the mirror S3 and the mirror S4, where S3 is a convex mirror and S4 is a concave mirror.
• an intermediate image Z1 is formed in or near the concave mirror S4, and an intermediate image Z2 of the projection objective is physically formed in the vicinity of the convex mirror S3.
• the imaging factor of the third partial objective which is also referred to as a transfer group, is 2.88x.
• the third partial objective is followed by a so-called relay group, which is also referred to as the second partial objective 200 and has an imaging factor of 1.18x.
• the second partial objective 200 in the present case comprises two mirrors, which are both designed as concave mirrors. These mirrors are therefore also referred to as primary concave mirror SK1 and secondary concave mirror SK2.
• the mirror S3 includes an aperture opening A1
• the secondary concave mirror SK2 includes an aperture opening A2, the primary concave mirror an aperture aperture A3, and the mirror S4 an aperture aperture A4.
• the mirrors S3, S4 SK1 and SK2 mirrors with an opening through which a beam tuft passes in the sense of the application.
• the mirror S3, S4, SK1, SK2 in the context of this application from a second sub-objective, which has only mirror with an opening for the passage of a beam tuft.
• the resulting radius providing the field-independent obscuration is 43% of the aperture radius.
• the mirrors S1, S2, S5 and S6 form a first sub-objective which does not have a mirror with an opening for the passage of a beam tuft, ie no pierced mirror.
• the distance A between the vertex V3, ie the vertex of the primary concave mirror SK1 and the image plane 20, ie the image-side working distance greater than 12 mm is preferred due to the formation of the mirror 20 closest to the image plane 20 as a concave mirror greater than 15 mm, more preferably greater than 40 mm.
• the object-side free working distance is 100 mm.
• the second partial objective 200 images the second intermediate image Z 2 into the image plane 20.
• the third partial objective connects the lower-aperture objective part to the high-aperture objective part.
• the third partial objective is therefore also called a transfer group.
• the maximum angle of incidence ⁇ c R ( max ) of the main beam to the central field point is on the mirrors S1, S2, S3, S4, S5, S6, SK1, SK2 ⁇ maX (max) 33.8 °.
• the maximum angle of incidence of each beam on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 38.6 °.
• the maximum angle range ⁇ max of the incident rays on each mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 12 °.
• the size of the largest mirror in the meridional section, ie in the meridional plane is 669 mm.
• the size of the largest mirror in the x-direction is 675 mm.
• optical data of the system according to FIG. 1q can be taken from the following table 1.
• Mirror 1 refers to the mirror S1 Mirror 2: the mirror S2 Mirror 3: the mirror S5 Mirror 4: the mirror S6
• Mirror 7 the primary concave mirror SK1
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 1 represents the optical data and the second part of Table 1 represents the aspheric constants of the respective mirror surfaces.
• the operating wavelength ⁇ is 13.5 nm.
• the resolution of the lens is 17 nm and the overall length is 1711 mm.
• the image-side W RM s is 0.044 ⁇ and the image-side field curvature is 12 nm.
• the obscuration radius, which ensures field-independent obscuration, is 36% of the aperture radius.
• the image-side free working distance is 69 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ c R (m a x) of the main beam to the central field point on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 19.4 °.
• the maximum angle of incidence ⁇ max (max) of any beam on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 21, 8 °.
• the maximum angle range ⁇ max of the incident rays on each mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 15 °.
• the largest mirror has a dimension in the meridional section of 385 mm and. the size of the largest mirror in the x-direction is 616 mm.
• Mirror 1 refers to the mirror S1
• Mirror 7 the primary concave mirror SK1
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 2 represents the optical data and the second part of Table 2 represents the aspherical constants of the respective mirror surfaces.
• the size of the field represented by the objective according to FIG. 2 is 13 ⁇ 1 mm 2 in the image plane.
• the aperture diaphragm B in the exemplary embodiment shown in FIG. 2 is on the convex mirror the transfer group - this is the mirror S3 - arranged.
• three partial objectives 100, 300 and 200 are formed.
• the partial objective 100 comprises the mirrors S1, S2, S5 and S6 and forms an intermediate image Z1 in or near the mirror S4.
• the second partial objective 200 comprises the mirrors SK1 and SK2 and the third partial objective 300 comprises the mirrors S3 and S4.
• the third partial lens forms an intermediate image Z2 in or near the mirror S3.
• FIG. 3 shows a similar 8-mirror system as in FIG. 2, but the magnification or the imaging factor in the exemplary embodiment in FIG. 3 is 5 ⁇ d. H. the image is reduced 5 times compared to the object.
• the field to be imaged, i. H. Image field has a size of
• the image-side free working distance is 69 mm and the object-side free working distance 104 mm.
• the maximum angle of incidence ⁇ c R (ma ⁇ ) on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 of the main beam to the central field point is 23.1 °.
• the maximum angle of incidence ⁇ maX (max) of each beam onto a mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 26.6 °.
• the maximum incidence range ⁇ max on any mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 16 °.
• the size of the largest mirror in the meridional section is 394 mm and the size of the largest mirror in the x-direction is 669 mm.
• the obscuration radius which provides field independent obscuration, is 35% of the aperture radius.
• the mirrors S3, S4, SK1 and SK2 include openings. The mirrors are designed so that three partial lenses are formed.
• the first partial objective comprises the mirrors S1, S2, S5 and S6 and forms an intermediate image Z1 in or near the mirror S5.
• the second partial objective 300 comprises two mirrors SK1 and SK2.
• the third partial objective comprises two mirrors S3 and S4.
• the diaphragm is formed on the third mirror S3.
• Mirror i refers to the mirror S1
• the first part of Table 3 represents the optical data and the second part of Table 3 represents the aspheric constants of the respective mirror surfaces.
• the resolution is 17 nm, the length of the system 1508 mm.
• the image-side W RM s is 0.006 ⁇ , the image-side field curvature is 2 nm.
• the resulting obscuration radius, which provides field-independent obscuration, is 31% of the aperture radius.
• the image-side free working distance is 69 mm and the object-side working distance 102 mm.
• ⁇ CR ( ma ⁇ ) of the main beam to the central field point on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 20 °.
• the maximum angle of incidence ⁇ maX (m ax ) of any beam on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 22.3 °.
• the maximum incidence range ⁇ max on any mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 13.6 °.
• the size of the largest mirror in the meridonal section is 396 mm and the size of the largest mirror in the x-direction is 575 mm.
• the mirror sequence in the light path from the object plane 10 to the image plane 20 is as follows:
• the mirrors S3, S4, SK1 and SK2 include openings.
• the mirrors S1, S2, S5 and S6 do not include openings.
• the first partial objective 100 comprises the mirrors S1, S2, S5 and S6.
• the first partial objective forms an intermediate image Z1 in the vicinity of the mirror S5.
• the second partial objective 200 comprises the mirrors SK1, SK2 and the third partial objective comprises the mirrors S3 and S4.
• the third partial objective 300 forms an intermediate image Z2.
• the system has three pupil levels and two intermediate images. At least one of the pupil planes is accessible to the placement of an aperture stop.
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 4 represents the optical data and the second part of Table 4 represents the aspherical constants of the respective mirror surfaces.
• the aperture stop B is disposed on the mirror S3 in the transfer group.
• the size of the field is in the embodiment of Figure 4 18-1 mm 2 .
• the resolution of the system is 17 nm, the overall length is 2000 mm.
• the image-side W RM s is 0.033 ⁇ and the image-side field curvature 7nm.
• the image-side free working distance is 61 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ c R (max) on a mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 of the main beam to the central field point is 15.9 °.
• the maximum angle of incidence ⁇ maX (ma ⁇ ) of each beam on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 17.9 °.
• the maximum range ⁇ max of the angles of incidence on each mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 10.6 °.
• the size of the largest mirror in the meridional section, ie in the meridional plane is 574 mm and the size of the largest mirror in the x direction 602 mm.
• the first partial objective 100 is the so-called field group comprising the mirrors S1, S2, S5 and S6 of essentially the same design as in the exemplary embodiments according to FIGS. 2, 3 and 4.
• the mirrors S1, S2, S5 and S6 have the following mirror sequence: convex-concave-convex-concave, d. H. the first mirror S1 in the light path from the object plane to the image plane has a convex mirror surface, the second mirror in the light path from the image plane to the object plane - the mirror S2 - has a concave mirror surface, the third mirror in the light path from the object plane 10 to the image plane 20 - Mirror S5 - has a convex
• Mirror surface and the fourth mirror in the light path from the object plane 10 to the image plane 20 - the mirror S6 - has a concave mirror surface.
• the optical path in the paper plane ie in the meridional plane spanned by the y, z direction, crosses over in the exemplary embodiments 2, 3, 4 and 5 in the first partial lens 100.
• the second partial objective 200 comprises the mirrors SK1 and SK2 and the third
• Partial objective the so-called transfer group, the mirrors S3 and S4.
• the mirrors S3, S4, SK1 and SK2 include openings, and the mirrors S1, S2, S5 and S6 do not include openings.
• the radius of the first mirror in the light path from the object plane to the image plane i. H. the radius of the mirror S1 is very large, for example. In the embodiment of Figure 5 is greater than 10 m.
• the first mirror S1 is thus formed almost flat and could not only be convex, in alternative embodiments also have a flat surface or a concave surface.
• the resulting obscuration radius which provides field independent obscuration, is 21% of the aperture radius.
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 5 represents the optical data and the second part of Table 5 represents the aspherical constants of the respective mirror surfaces.
• FIG. 6 a shows a further exemplary embodiment of an 8-mirror system in which the first partial objective 100, that is to say the field group, has the same mirror sequence as the preceding exemplary embodiments, but differences also arise. So is.
• the mirror sequence of the four mirrors S1, S2, S5 and S6 of the first partial objective 100 is convex-concave-convex-concave.
• the beam path in the first partial objective 100 does not intersect. Due to the different beam guidance in the first part of the objective 100, the first mirror S1 in the embodiment shown in FIG 6a not alternatively plan or concave.
• the resolution of the system is 14 nm, the length is 2500 mm.
• the image-side WRM S is 0.017 ⁇ .
• the image-side field curvature is 1 nm.
• the resulting obscuration radius, which provides field-independent obscuration, is 22% of the aperture radius.
• the image-side free working distance is 55 mm, the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ cR (m a ⁇ ) on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 of the main beam to the central field point is 28.3 °.
• the maximum angle of incidence ⁇ ma ⁇ (max) of each beam on the mirrors S1, S2, S3, S4, S5, S6, SK1 and SK2 is 36.6 °.
• the maximum angle range ⁇ max of the incident rays on each mirror S1, S2, S3, S4, S5, S6, SK1 and SK2 is 16.6 °.
• the size of the largest mirror in meridonal section is 778 mm.
• the size of the largest mirror in the x-direction is 806 mm.
• the system comprises three partial lenses, a first partial objective 100, a second partial objective 300 and a third partial objective 200.
• the first partial objective 100 comprises the mirrors S1, S2, S5 and S6 and forms an intermediate image Z1 near the mirror S4.
• the second partial objective comprises the mirrors SK1 and SK2 and the third partial objective comprises the mirrors S3, S4 and forms an intermediate image Z2.
• the mirrors S3, S4, SK1 and SK2 include openings, the mirrors S1, S2, S5 and S6 do not include openings.
• the mirror sequence in the light path from the object plane 10 to the image plane 20 is as follows:
• Mirror i refers to the mirror S1
• Mirror 7 the primary concave mirror SK1
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 6a represents the optical data and the second part of Table 6a represents the aspherical constants of the respective mirror surfaces.
• the objective shown in FIG. 6b has, in contrast to that shown in FIG Objectively no transfer group, but only a field group, ie, a first partial objective 100 and a second partial objective 200, which is also referred to as a relay group.
• the relay group comprises two concave mirrors SK1 and SK2.
• the field group includes mirrors SP1, SP2, SP3, SP4, SP5 and SP6.
• the mirror sequence of the six mirrors of the field group SP1, SP2, SP3, SP4, SP5 and SP6 of the first partial objective 100 is concave-concave-convex-concave-convex-concave. All SP1, SP2, SP3, SP4, SP5 and SP6 of the array are off-axis mirror segments. None of the mirrors has an opening for the passage of a jet tuft.
• the system shown in FIG. 6b has two intermediate images ZWISCH1 and ZWISCH2.
• the diaphragm B is arranged in the first subsystem 100 on or near the second mirror SP2. However, it can also be placed in this system between the two concave mirrors of the aperture group, since there is a conjugated diaphragm plane.
• the resolution is 14 nm, the image-side W RM s 0.018 ⁇ , the image-side field curvature 2 nm.
• the image-side free working distance is 15 mm and the object-side free working distance 100 mm.
• the resulting obscuration radius which provides field independent obscuration, is 22% of the aperture radius.
• the maximum angle of incidence ⁇ c R (m a x ) on the mirrors SP1 to SP8 of a main beam to a central field point is 30.1 °.
• the maximum angle of incidence ⁇ ma ⁇ (max) of each beam on a mirror SP1 to SP8 is 31, 5 °.
• the maximum incident angle range ⁇ ma ⁇ of the incident rays on any mirror SP1 to SP8 is 29 °.
• the size of the largest mirror in the meridonal section is 621 mm and the size of the largest mirror in the x-direction is 668 mm.
• the overall length of the system is 2000 mm.
• Mirror 7 the primary concave mirror SK1
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 6b represents the optical data and the second part of Table 6b represents the aspherical constants of the respective mirror surfaces.
• Table 6b Optical data for the system according to FIG. 6b:
• FIG. 6c shows a variant of the exemplary embodiment shown in FIG. 6b.
• the mirror sequence in the array with the mirrors SP1, SP2, SP3, SP4, SP5 and SP6 is the same as in the embodiment in Figure 6b, namely concave - concave - convex - concave - convex - concave.
• the aperture group consists of two concave mirrors SP7 and SP8. In contrast to
• the aperture diaphragm is not on the mirror SP2 but between the concave mirrors SP7 and SP8 of the aperture group.
• the mirror with the smallest axial distance along the main axis HA of the objective to the object plane 10 is not the second mirror SP2 of the field group but the fourth mirror SP4 of the field group.
• a particularly long drift path is provided between the fourth mirror SP4 and the fifth mirror SP5, which results in very small angles of incidence on the mirrors SP4 and SP5.
• the maximum angle of the main beam to the central field point occurs on the third mirror SP3 and is only 21 °.
• the resolution of the system is 14 nm.
• the image-side W RM s is 0.015 ⁇ and the image-side field curvature is 1 nm.
• the resulting obscuration radius, which provides field-independent obscuration, is 29 ° of the aperture radius.
• the image-side free working distance is 40 mm and the object-side free working distance 322 mm.
• the maximum angle ⁇ cR (max) of the main beam to the central field point on any mirror SP1 to SP8 is 21 °.
• the maximum angle ⁇ max (max) of any beam on any mirror SP1 to SP8 is 25.2 °.
• the maximum angle range ⁇ max on any mirror SP1 to SP8 is 24.9 °.
• the size of the largest mirror in the meridional section is 682 mm and the size of the largest mirror in the x-direction is 694 mm.
• the objective again comprises two partial objectives, a first partial objective comprising the mirrors SP1, SP2, SP3, SP4, SP5 and SP6 and a second partial objective comprising the mirrors SP7 and SP8.
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 6c represents the optical data and the second part of Table 6c represents the aspheric constants of the respective mirror surfaces.
• Table 6c Optical data for the system according to FIG. 6c:
• the objective shown in FIG. 6d has no transfer group, as in the embodiment of FIG. 6b, but only one field group, ie a first partial objective 100 and a second partial objective 200, which is also referred to as a relay group.
• the relay group, ie the second partial objective 200 comprises two concave mirrors SK1 and SK2.
• the field group, ie the partial objective 100 comprises the mirrors SP1, SP2, SP3, SP4, SP5 and SP6, which are designed as off-axis segments.
• the mirror sequence of the six mirrors of the array SP1, SP2, SP3, SP4, SP5 and SP6 of the first sub-objective 100 is concave-convex-concave-convex-convex-concave.
• the system shown in FIG. 6d comprises two intermediate images ZWISCH1 and BETWE2.
• the diaphragm B is arranged between the first concave mirror SK 1 and the second concave mirror SK 2 of the second partial objective 200.
• the aperture diaphragm can also be placed between the first and the second mirror or directly on the first or directly on the second mirror.
• the resolution is 14 nm and the length of the system, ie the length 2000 mm.
• the image-side W RM s is 0.025 ⁇ and the image-side field curvature, ie the field curvature 5 nm.
• the resulting obscuration radius which provides a field-independent obscuration, is 26% of the aperture radius.
• Working distance is 41 mm.
• the object-side working distance is 402 mm.
• the maximum angle of incidence ⁇ c R (m a x) on a mirror SP1 to SP8 of a main beam of a central field point is 26.1 °.
• the maximum angle of incidence ⁇ maX (max) of any beam on the mirrors SP1 to SP8 is 29.8 °.
• the maximum incident angle range ⁇ max to any mirror SP1 to SP8 is 21 °.
• the size of the largest mirror in the meridional section is 753 mm and the size of the largest mirror in the x-direction is 765 mm.
• the optical data of the system according to FIG. 6d can be taken from Table 6d:
• Mirror 7 the primary concave mirror SK1
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 6d represents the optical data and the second part of Table 6d represents the aspheric constants of the respective mirror surfaces.
• Table 6d Optical data for the system according to FIG. 6d:
• FIG. 6e shows a variant of the exemplary embodiment shown in FIG. 6d.
• the embodiment according to FIG. 6e has a similar mirror sequence in the field group, ie the first partial objective with the mirrors SP1, SP2, SP3, SP4, SP5 and SP6, like the exemplary embodiment according to FIG. 6d, namely concave-concave-concave-convex-convex-concave , wherein the radius of the mirror 2 (Mirror 2) is so large that this mirror can also be designed flat or convex.
• Intermediate image INTER1 lies within the array between mirrors SP2 and SP3 and physically at the bottom of mirror SP4.
• the beam cross section at the mirror SP4 can be kept very small and the field group has a particularly compact construction on.
• the embodiment is characterized by very low angles of incidence of the main beam to the central field point. The largest angle of incidence of the main beam to the central field point occurs on the mirror SP4 and is only 24 °. The length of the lens is 1974 mm.
• the resolution is 12 nm and the length of the system 1974 mm.
• the image-side WR MS is 0.021 ⁇ and the image-side field curvature 1 nm.
• the image-side free working distance is 41 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ c R (max ) on a mirror SP1 to SP8 of a main beam to a central field point is 22.9 °.
• the maximum angle of incidence ⁇ ma ⁇ ( m a x ) of any beam on a mirror SP1 to SP8 is 26.7 °.
• the maximum incident angle range ⁇ max to any mirror SP1 to SP8 is 23.3 °.
• the resulting obscuration radius, which provides field independent obscuration, is 23% of the aperture radius.
• the size of the largest mirror in the meridional section is 904 mm, the size of the largest mirror in the x-direction is 916 mm.
• optical data of the system according to FIG. 6e can be taken from Table 6e:
• Mirror 8 the secondary concave mirror SK2
• the first part of Table 6e represents the optical data and the second part of Table 6e the aspheric constants of the respective mirror surfaces.
• Table 6e Optical data for the system according to FIG. 6e
• the first partial objective 100 denotes the first partial objective, 200 the second partial objective and 300 the third partial lens.
• the first partial objective 100 comprises a mirror S10, a mirror S20, a mirror S50, a mirror S60, a mirror S70 and a mirror S80.
• the mirror S10 is a convex mirror with a very large radius of more than 10,000 mm. Because of this large radius, the mirror S1 can be made both flat and concave.
• the mirror S20 following in the light path is a concave mirror
• the mirror S70 is a convex mirror
• the mirror S80 is a concave mirror
• the mirror S90 is a concave mirror
• the mirror S100 is a convex mirror so that the mirror sequence is convex-concave-convex-concave - concave-convex results.
• the mirror sequences could also be concave-concave-convex-concave-concave-convex or plan-concave-convex-concave-concave-convex.
• the aperture diaphragm B is arranged on the mirror S20.
• the imaging factor of the first partial objective 100 is 1.85x
• the imaging factor of the third partial objective 300 is 3.38x
• the imaging factor of the second partial objective 200 is 1.3.
• the overall length of the system is 2508 mm.
• the resolution of the system is approximately 11 nm, the image-side field curvature less than 1 nm.
• the resulting obscuration radius, which provides field-independent obscuration, is 55% of the aperture radius.
• the image-side free working distance is 41 mm and the object-side free working distance 100 mm.
• the maximum angle ⁇ cR (max) incident on a mirror S10, S20, S30, S40, S50, S60, S70, S80, SK1 and SK2 of the main beam of a central field point is 32.9 °.
• the maximum angle of incidence ⁇ m ax (max) any beam on a mirror S10, S20, S30, S40, S50, S60, S70, S80, SK1 and SK2 is 45.1 °.
• the maximum incident angle range ⁇ max to any mirror S10, S20, S30, S40, S50, S60, S70, S80, SK1 and SK2 is 28 °.
• the size of the largest mirror in the meridional section is 932 mm and the size of the largest Mirror in x-direction 1034 mm.
• the mirrors S30, S40, S70, SK1 and SK2 include openings.
• the mirrors S10, S20, S50, S60, S80 have no openings.
• the first partial objective 100 comprises the mirrors S10, S20, S50, S60, S70 and S80.
• the first partial objective forms the intermediate image Z1 in a position between the mirror S40 and S70.
• the second partial objective comprises the mirrors SK1 and SK2 and the third partial objective comprises the mirrors S30 and S40.
• the system according to FIG. 7 and also FIG. 8 is characterized in that it is a pupil-obscured system with at least one mirror with an opening for the passage of a bundle of rays, wherein the aperture diaphragm B, which in the present case is arranged on the second mirror S20 is, in front of the intermediate image Z2 is arranged. Due to the fact that the aperture diaphragm is arranged in front of the last intermediate image (Z2), at least one intermediate image lies between the aperture diaphragm B and the image plane 20.
• Mirror 10 the secondary concave mirror SK2
• Table 7 gives the aspheric constants of the individual mirror surfaces.
• FIG. 8 shows a variation of the exemplary embodiment as shown in FIG.
• the wavefront is at a center Wavefront error Wrms of 0.024 ⁇ and the resolution is 11 nm and the length of the system 2511 mm.
• the image-side field curvature is 3 nm.
• the resulting obscuration radius which provides field-independent obscuration, is 55% of the aperture radius.
• the image-side free working distance is 40 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ CR (m a ⁇ ) on a mirror S10 to S80, SK1 and SK2 of a main beam to a central field point is 32.5 °.
• the maximum angle of incidence .theta..sub.M a x (a x m) of any ray on a mirror S10 to S80, SK1 and SK2 is 45.1 °.
• the maximum incident angle range ⁇ max to any mirror S10 to S80, SK1 and SK2 is 28.9 °.
• the size of the largest mirror in the meridional section is 933 mm, the size of the largest mirror in the x-direction is 1028 mm.
• the third partial objective both in FIG. 7 and in FIG. 8 is denoted by 300 and comprises the convex mirror S30 and the concave mirror S40.
• the first intermediate image is denoted by Z1, the second intermediate image by Z2.
• the second partial objective 200 comprises two concave mirrors, namely the primary concave mirror SK1 and the secondary concave mirror SK2.
• Concave mirror SK2 is the last mirror in the light path and the mirror S30 is the fourth-last-most mirror in the light path relative to the image plane 20.
• the system in FIG. 8 is subdivided into three partial objectives, a first partial objective 100, a second partial objective 200 and a third partial objective 300.
• the first partial objective 100 is subdivided into three partial objectives, a first partial objective 100, a second partial objective 200 and a third partial objective 300.
• the first partial objective 100 is subdivided into three partial objectives, a first partial objective 100, a second partial objective 200 and a third partial objective 300.
• Partial objective comprises the mirrors S10, S20, S50, S60, S70 and S80, the second partial objective the mirrors SK1 and SK2 and the third partial objective the mirrors S30 and S40.
• the mirror S10 is a convex mirror
• the mirror S20 is a concave mirror
• the mirror S50 is a convex mirror
• the mirror S60 is a concave mirror
• the mirror S70 is a concave mirror
• the mirror S80 is a convex mirror
• Mirror S30 is a convex mirror
• mirror S40 is a concave mirror
• mirror SK1 is a concave mirror
• mirror SK2 is a concave mirror.
• the mirrors S30, S40, S70, SK1 and SK2 include openings.
• the mirrors S10, S20, S50, S60 and S80 do not include openings.
• the aperture stop B is arranged on the second mirror.
• the resolution is 12 nm and the overall length of the system 2494 mm.
• the image-side W ms is 0.018 ⁇ and the image-side field curvature less than 1 nm.
• the resulting obscuration radius which provides field independent obscuration, is 26% of the aperture radius.
• the image-side free working distance is 40 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ c R ( ma ⁇ ) on a mirror S10 to S80, SK1 and SK2 of a main beam to a central field point is 32.7 °.
• the maximum angle of incidence ⁇ maX ( m a ⁇ ) of any beam on a mirror S10 to S80, SK1 and SK2 is 42.3 °.
• the maximum incident angle range ⁇ max to any mirror S10 to S80, SK1 and SK2 is 18.8 °.
• the size of the largest mirror in the meridional section is 858 mm, the size of the largest mirror in the x direction is 891 mm.
• the system according to FIG. 9 comprises three partial objectives.
• the first partial objective comprises the mirrors S10, S20, S50, S60, S70 and S80 and forms an intermediate image Z1 near or at the mirror S40.
• the second partial objective comprises the mirrors SK1 and SK2.
• the third partial objective comprises the mirrors S30 and S40 and forms an intermediate image Z2 between the mirror S30 and SK2.
• the mirror S10 is a convex mirror
• the mirror S20 is a concave mirror
• the mirror S50 is a concave mirror
• the mirror S60 is a convex mirror
• the mirror S70 is a convex mirror
• the mirror S80 is a concave mirror
• the mirror S40 is a convex mirror
• optical data of the system according to FIG. 9 can be taken from Table 9.
• Mirror 1 refers to the mirror S10 Mirror 2: the mirror S20 Mirror 3: the mirror S50 Mirror 4: the mirror S60 Mirror 5: the mirror S70 Mirror 6: the mirror S80
• the systems according to FIGS. 2, 3, 4, 5, 6, 7, 8 and 9 furthermore have the advantageous property that the objective, in particular the microlithography projection objective, is a first sub-objective, which does not have a mirror with an opening for the passage of a ray bundle comprising, ie, having no pierced mirror, and a second sub-objective, which has no mirror without an opening for the passage of a beam tuft comprises, and the geometric distance between the first sub-objective and the second sub-objective is at least 10% of a length of the projection system.
• the length of an objective is understood to be the distance along the optical axis HA from the object plane 10 to the image plane 20.
• the distance from the vertex or the vertex of the mirror of the first sub-objective, which has the smallest distance to the image plane, to the vertex of the mirror of the second sub-objective is defined by the geometric or spatial distance between the first sub-objective SUBO1 and the second sub-objective SUBO2. which has the smallest distance to the object plane understood.
• the mirror of the second super-objective which has the smallest distance to the object plane, is also referred to as the second mirror objective of the second sub-objective
• the mirror of the first sub-lens having the smallest distance to the image plane is referred to as the wafer-proximate mirror of the first sub-objective.
• the distance between the two sub-objectives SUBO1, SUBO2 is negative, since the two sub-objectives are spatially nested, i.e. the mirror S70 lies spatially in the area of the second sub-objective.
• Such an arrangement has the advantage that when the second mirror objective of the second sub-objective has only a small distance to the wafer-near mirror of the first sub-objective, the inner ring-field radius and thus the Obscuration can be kept small.
• FIGS. 2, 3, 4, 5, 6a, 9 as well as those shown in the following FIGS. 16, 17 and 18 are characterized by a negative intercept of the entrance pupil.
• a negative intercept of the entrance pupil means that the principal rays of the various field points in the direction of light from the object plane start diverging into the objective, i. in the light direction, run into it.
• This means that the entrance pupil of the projection objective in the light path from a light source of an illumination system to the object plane in which a reflective reticle is arranged is arranged in front of the object plane.
• Such projection lenses and projection exposure systems are shown for example in WO2004 / 010224, the disclosure content of which is fully included in the present application.
• the first subsystem 100 consists of 6 mirrors S10, S20, S50, S60, S70, S80 in the mirror sequence convex-concave-convex-concave-convex-concave.
• the aperture diaphragm B lies on the second mirror S20 of the first partial objective 100.
• the radius of the first mirror is so large that the mirror S10 can be formed not only convex but also flat or concave. Therefore, the following mirror sequences are also possible:
• the first subsystem 100 of this projection objective has an intermediate image Z3 which is arranged between the fourth and the fifth mirror, the mirrors S60 and S70, in the light path from the object plane to the image plane.
• the magnifications of the first sub-objective 100, the third sub-objective 300 and the second sub-objective 200 are respectively 2.78x, 2.24x and 1.29x.
• the exemplary embodiment according to FIG. 10 is characterized in that the angles of incidence of the main beam of the central field point of the field to be imaged in the field plane are particularly small in the present example. Furthermore, the system is characterized by the fact that the area fraction of obscuration in the pupil is only 10%.
• the same components as in Figures 7 and 8 are assigned the same reference numerals.
• the aperture diaphragm B lies on the second mirror S20.
• the resolution is 12 nm and the length of the system 2500 mm.
• the image-side W rms is 0.041 ⁇ .
• the image-side field curvature is 4 nm.
• the resulting obscuration radius, which provides field-independent obscuration, is 27% of the aperture radius.
• the image-side free working distance is 40 mm and the object-side free working distance 100 mm. The maximum
• Incident angle ⁇ c R (m a x) on a mirror S10 to S80, SK1 and SK2 of a main beam CR to a central field point is 20 °.
• the maximum angle of incidence ⁇ maX (m a x) of any beam onto a mirror S10 to S80, SK1 and SK2 is 27.7 °.
• the maximum incident angle range ⁇ max to any mirror S10 to S80, SK1 and SK2 is 20.9 °.
• the size of the largest mirror in the meridional section is 884 mm, the size of the largest mirror in the x-direction is 927 mm.
• the objective shown in FIG. 11 comprises three partial objectives, a first partial objective 100 with the mirrors S10, S20, S50, S60, S70 and S80, a second partial objective
• Partial objective with mirrors SK1 and SK2 and a third partial objective with mirrors S30 and S40.
• the mirrors In the light path from the object plane to the image plane, the mirrors have the following mirror sequence:
• the second part of Table 10 gives the aspherical constants of the individual mirror surfaces.
• the first partial objective 100 comprises six mirrors S10, S20, S50, S60, S70, S80 with the mirror sequence concave-convex-concave-concave-convex-concave.
• the mirrors SK1, SK2 of the second partial objective 200 are two concave mirrors.
• the mirror S30 is a convex mirror and the mirror S40 is a concave mirror.
• the aperture diaphragm B is in the embodiment of FIG 11 on the seventh in the light path mirror, d. H. the mirror S30, arranged and thus in the third part of the objective 300, d. H. relocated the transfer group.
• the resolution is 12 nm and the system length is 2246 mm.
• the image-side W rms is 0.3 ⁇ .
• the image-side field curvature is 27 nm.
• the resulting obscuration radius, which provides field independent obscuration, is 28% of the aperture radius.
• the image-side free working distance is 40 mm and the object-side free working distance 468 mm.
• the maximum angle of incidence ⁇ cR (max) on a mirror S10 to S80, SK1 and SK2 of a main beam to a central field point is 35.3 °.
• the maximum angle of incidence ⁇ ma ⁇ (m a x) of any beam on a mirror S10 to S80, SK1 and SK2 is 42.4 °.
• the maximum incident angle range ⁇ ma ⁇ on any mirror S10 to S80, SK1 and SK2 is 18.9 °.
• the size of the largest mirror in the meridional section is 836 mm, the size of the largest mirror in the x-direction is 834 mm.
• the optical data can be taken from Table 11.
• the first partial objective comprises six mirrors, namely the mirrors S10, S20, S50, S60, S70, S80.
• the mirror sequence is concave - convex - concave - convex - convex - concave.
• an intermediate image Z3 is formed here in the first subsystem, namely between the second mirror S20 in the light path from object to image and the third mirror S50 in the light path from
• the aperture diaphragm B is arranged on the mirror S10 in the illustrated embodiment.
• the resolution is 12 nm and the length of the system 2800 mm.
• the image side W m s is 0,052 ⁇ and the image side field radius 7 nm.
• the image side free working distance is 41 mm and the object side free working distance 729 mm.
• the maximum angle of incidence ⁇ c R (m a x) on a mirror S10 to S80, SK1 and SK2 of a main beam to a central field point is 35 °.
• the maximum angle of incidence ⁇ maX (max) of any beam on a mirror S10 to S80, SK1 and SK2 is 39.6 °.
• the maximum incident angle range ⁇ max to any mirror S10 to S80, SK1 and SK2 is 24.5 °.
• the size of the largest mirror in the meridional section is 871 mm, the size of the largest mirror in the x-direction is 918 mm.
• the mirrors S30, S40, SK1 and SK2 include openings, the mirrors S10, S20, S50, S60, S70 and S80 have no openings.
• Mirror 1 the mirror S10
• Mirror 2 the mirror S20
• Mirrqr 3 the mirror S50
• Mirror 10 the secondary concave mirror SK2
• Table 12 gives the aspheric constants of the individual mirror surfaces.
• FIGS. 11 and 12 are further characterized in that they are systems with six or more mirrors, wherein at least one mirror has no opening for the passage of a jet tuft and the mirror which has no opening and the has the smallest distance to the object plane 10, has a distance to the object plane, which is greater than 15% of the length of the lens.
• Such a large object-side working distance results in sufficient space for mechanical components, eg a reticle layer or additional optical components, eg optical filter elements, which are to achieve a field-dependent effect and therefore have to be arranged in the vicinity of a field plane.
• mechanical components eg a reticle layer or additional optical components, eg optical filter elements
• the mirror which has no opening and the smallest distance to the object plane along the optical axis, has the mirror S20.
• the distance of the mirror S20 to the object plane 10 is in turn defined by the distance of the vertex V20 of the mirror S20 to the object plane 10, the overall length as indicated above.
• FIG. 13 shows in detail the second subsystem 200 and the third subsystem 300 of the projection objectives described in the application.
• the intermediate image Z 2 is arranged at the location of the convex mirror 1000 of the third sub-objective 300.
• the intermediate image at the location of the convex mirror according to FIG. 13 leads to an area obscuration of 10% in the pupil of the projection objective. If, on the other hand, the intermediate image Z2 is arranged, as shown in FIG.
• FIG. 15 shows a system in which a manganese mirror is used instead of a mirror element 1020.
• a system with a manganese mirror has the advantage that the space required to mount the mirror is provided by the optical element 1100, through which the light must pass and the reflective surface, i. H. the mirror surface is located on the back of the optical element 1100. As a result, the mirror next to the wafer can be arranged very close to the image plane without impairing the stability.
• Light is required by the optical element 1100 and this must have a certain transparency so far.
• FIG. 16 shows an embodiment of a projection lens with a mangin mirror 1100.
• the first lens part 100 includes six mirrors S10, S20, S50, S60, S70, S80, the third lens part includes two mirrors S30 and S40 and the second objective part include two concave mirrors SK1 and SK2, and the primary concave mirror SK1 closest to the image plane is a mangin mirror 1100 as described above.
• Reduction of the system is 8x and the resolution 100 nm.
• the system length of 2500 mm.
• the image-side W rms is 0.023 ⁇ and the image-side field curvature 59 nm.
• the resulting Obskurationsradius is 28% of the aperture radius.
• the image-side optical free working distance is 10 mm and the object-side free working distance 100 mm.
• the maximum angle of incidence ⁇ c R ( max ) on a mirror S10 to S80, SK1 and SK2 of a main beam to a central field point is 37.6 °.
• the maximum angle of incidence ⁇ maX (max) of any beam onto a mirror S10 to S80, SK1 and SK2 is 49.4 °.
• the maximum incident angle range ⁇ max to any mirror S10 to S80, SK1 and SK2 is 22.4 °.
• the size of the largest mirror in the meridional section is 889 mm, the size of the largest mirror in the x-direction is 883 mm.
• the mirror sequence from the object plane 10 to the image plane 20 is as follows:
• the mirror SK1 is a mangin mirror as described above.
• the object-side working distance is 100 mm and the image-side working distance is 10 mm.
• the first partial objective comprises the mirrors S10, S20, S50, S60, S70 and S80 and forms an intermediate image Z1 near the mirror S40.
• the second partial objective comprises the mirrors SK1 and SK2.
• the third partial objective comprises the mirrors S30 and S40.
• the mirrors S30, S40, SK1 and SK2 include openings.
• the mirrors S10, S20, S50, S60, S70 and S80 do not include openings.
• optical data of the system according to FIG. 16 are given in Table 13.

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• 2005
  • 2005-12-22 WO PCT/EP2005/013841 patent/WO2006069725A1/de not_active Ceased
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