Color-corrected imaging illumination optical unit for use in a lithographic projection exposure apparatus

Abstract

The color-corrected imaging illumination optical unit (20) is useful for use in a lithography projection exposure apparatus, in particular for imaging an illumination-adjusted field (16a) via an imaging beam path (23) into an object field (14) of a downstream projection optical unit in a manner compatible with the downstream projection optical unit. The illumination optical unit (20) has at least seven and up to twelve lens elements (L1-L9) in the imaging beam path (23). The illumination optical unit (20) has a total transmittance for illumination light of at least 85%. This results in an illumination optical unit that can be used to increase the throughput of a projection exposure apparatus to which it is attached and to achieve high illumination quality.

Description

[Technical Field]

[0001] This patent application claims priority from German Patent Application No. 10 2023 200 548.4, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a color-corrected imaging illumination optical unit for use in a lithographic projection exposure apparatus. The invention also relates to an optical system within such an illumination optical unit, an illumination system comprising such an illumination optical unit, a projection exposure apparatus comprising such an illumination system, a method for producing a structured part using such a projection exposure apparatus, and a structured part produced using such a method. [Background technology]

[0003] Illumination optical units of the type mentioned in the introduction are known from DE-A 196 53 983, US Pat. No. 5,982,558, US Pat. No. 7,551,361, DE-A 101 13 612 and WO 2009 / 095052.

[0004] German Patent Application No. 103 02 765 discloses an optical device with lens elements made of uniaxially refractive material. German Patent Application No. 10 2015 218 328 discloses an optical system for field imaging and / or pupil imaging. German Patent Application No. 10 2008 015 775 discloses a color-corrected lithography lens. German Patent Application No. 10 2017 207 582 discloses a projection lens, a projection exposure apparatus, and a projection exposure method. Summary of the Invention

[0005] The object of the invention is to develop an illumination optical unit of the type mentioned in the introduction in such a way that it is possible to increase the throughput of the projection exposure apparatus to which it is attached and to achieve a high illumination quality.

[0006] According to the invention, this object is achieved by a color-corrected imaging illumination optical unit having the features set forth in claim 1.

[0007] According to the present invention, it has been found that an illumination optical unit having 7 to 12 lens elements and a total transmittance of at least 85% leads to both high throughput and good error correction potential due to the number of optical lens element surfaces of the illumination optical unit. The total transmittance of the illumination optical unit for illumination light may be at least 88%, at least 90%, or at least 91%. The illumination optical unit may be rotationally symmetrical about the optical axis. The illumination adjustment field of the illumination optical unit may be preset via a REMA diaphragm of the projection exposure apparatus. The adjustment field is then located in the alignment plane relative to the REMA diaphragm. Details regarding the effect of such a REMA diaphragm are described in the aforementioned documents. The object field of the illumination optical unit may have a diameter greater than 10 mm corrected for imaging aberrations. The diameter of the object field corrected for imaging aberrations may be greater than 25 mm, greater than 50 mm, or greater than 100 mm. The diameter of the object field corrected for imaging aberrations may be in the region of 120 mm.

[0008] The illumination optical unit may include exactly seven lens elements. Alternatively, the illumination optical unit may also include exactly eight lens elements, exactly nine lens elements, exactly ten lens elements, exactly eleven lens elements, or exactly twelve lens elements. In addition to the lens elements, the illumination optical unit may also include at least one plane-parallel optical component, for example a filter component.

[0009] The aspherical form of the illumination optical unit according to claim 2 allows for an improvement in illumination quality. At least three, four, or at least five of the lens elements may be aspherical lens elements. It is also possible for all lens elements of the illumination optical unit to be aspherical lens elements. An aspherical lens element is a lens element having at least one aspherical surface. It is also possible for both the entrance surface and the exit surface of the aspherical lens element to have an aspherical form.

[0010] The design according to claim 3 is suitable for a corresponding light source of a projection exposure apparatus, in particular for an i-line light source of a mercury vapor source. The illumination optical unit may also be suitable for other UV or DUV wavelengths, for example 248 nm or 193 nm.

[0011] A refractive design of the illumination optical unit, i.e., a design without curved mirrors, has manufacturing advantages. Such a refractive design of the illumination optical unit may be configured with or without at least one flat deflection mirror.

[0012] Up to three different lens element materials in the illumination optical unit reduce manufacturing costs. The illumination optical unit particularly comprises up to two lens element materials, which further reduces manufacturing costs. Surprisingly, it has also been found that reducing the number of lens element materials still allows for sufficiently good color correction.

[0013] One of the lens element materials may be flint glass. One of the lens element materials may be crown glass. One of the lens element materials may be quartz glass. When two different lens element materials are used, this may involve, for example, a combination of flint glass and quartz glass.

[0014] The doublet according to claim 6 allows for good color correction along with a compact structure. The cross-sectional coordinate area of ​​the beam path coordinates along the optical axis of the illumination optical unit, where a plane perpendicular to the optical axis within this coordinate area intersects both the concave lens element of the doublet and the adjacent lens element, may have an extent of more than 5 mm, and may also have an extent of more than 10 mm, 15 mm, or 20 mm. This cross-sectional coordinate area is typically less than 50 mm. The illumination optical unit may comprise a multiple lens element doublet, in particular a multiple doublet as discussed above.

[0015] This applies in particular to a triplet as claimed in claim 7. The above explanation regarding claim 6 applies to the extent of at least one cross-sectional coordinate area. The illumination optical unit may comprise a plurality of lens element triplets, in particular a plurality of triplets as discussed above.

[0016] The separate cross-sectional coordinate areas according to claim 8 result in the biconcave lens elements fitting into the corresponding convex lens element surfaces of the adjacent lens elements on both sides. This results in a particularly compact structure with good color correction. The above explanation regarding claim 6 applies to the extent of the cross-sectional coordinate areas.

[0017] The narrowing of the overall beam as claimed in claim 9 reduces the size requirements for the plane deflection mirror.

[0018] The magnification effect according to claim 10 allows for good control of the illumination of the object field. The absolute magnification may be 4. The illumination optical unit may be designed without an intermediate image.

[0019] The advantages of the optical system according to claim 11, the illumination system according to claim 12, the projection exposure apparatus according to claim 13, the manufacturing method according to claim 14 and the structured component according to claim 15 correspond to the advantages already explained above for the illumination optical unit. The light source of the illumination system may be a mercury lamp, an excimer laser or an LED light source.

[0020] Structured components, in particular microchips, for example memory chips, can be produced.

[0021] Exemplary embodiments of the invention are described in more detail below with reference to the drawings. [Brief explanation of the drawings]

[0022] [Figure 1] 1 shows a schematic meridian section through the optical main group of a microlithographic projection exposure apparatus; [Figure 2] 1 shows a meridional section through a color-corrected imaging illumination optical unit for use in a projection exposure apparatus; [Figure 3] 3A and 3B each show a view similar to FIG. 2 of a further embodiment of a color-corrected imaging illumination optical unit for use in a projection exposure apparatus. [Figure 4] 3A and 3B each show a view similar to FIG. 2 of a further embodiment of a color-corrected imaging illumination optical unit for use in a projection exposure apparatus. [Figure 5] 3A and 3B each show a view similar to FIG. 2 of a further embodiment of a color-corrected imaging illumination optical unit for use in a projection exposure apparatus. [Figure 6] 3A and 3B each show a view similar to FIG. 2 of a further embodiment of a color-corrected imaging illumination optical unit for use in a projection exposure apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0023] The projection exposure apparatus 1 is illustrated schematically in a meridian section in Figure 1 with respect to its optical main group. This schematic shows the optical main group as a refractive optical element. The optical main group may be in the form of a diffractive or reflective component of an optical element, or a combined or sub-combined refractive / diffractive / reflective assembly.

[0024] To facilitate the description of positional relationships, an xyz coordinate system will be used below. In Fig. 1, the x-axis extends perpendicular to the plane of the drawing. The y-axis extends upwards in Fig. 1. In Fig. 1, the y-axis extends to the right, parallel to the optical axis 2 of the projection exposure apparatus 1. This optical axis 2 may optionally be folded back several times.

[0025] The projection exposure apparatus 1 comprises a radiation source 3 which generates working light in the form of an illumination or imaging beam 4. The wavelength of the working light 4 is in the deep ultraviolet (DUV) range, for example in the range of 100 nm to 200 nm, or in the ultraviolet (UV) range of 200 nm to 400 nm. Alternatively, the working light 4 may have a wavelength in the extreme ultraviolet (EUV) range, in particular in the range of 5 nm to 30 nm. Exemplary wavelengths of the beam source 3 are 365 nm, 248 nm, or 193 nm. Depending on the radiation source 3 used, the working wavelength spectrum employed may be narrowband, but may also have a larger broadband capacity, for example if a mercury discharge lamp is used.

[0026] An illumination optical unit 5 of the projection exposure apparatus 1 guides the used light 4 from the radiation source 3 into an object plane 6 of the projection exposure apparatus 1. An object in the form of a reticle 7 to be imaged by the projection exposure apparatus 1 is arranged in the object plane 6. The reticle 7 is illustrated by dashed lines in Figure 1. The reticle 7 is carried by a holder, not illustrated, which allows a controlled scanning or stepwise displacement.

[0027] As a first optical main group, the illumination optical unit 5 first comprises a pupil-forming optical unit 8. This functions to generate a predetermined intensity distribution of the used light 4 in a downstream pupil plane 9. The pupil-forming optical unit 8 further functions as a setting device for presetting various illumination settings. For example, corresponding setting devices with adjustable optical components or exchangeable diaphragms are known to those skilled in the art. The pupil-forming optical unit 8 converts the radiation source 3 into multiple secondary light sources in the pupil plane 9. The pupil-forming optical unit 8 may additionally have a field-forming function. Faceted elements, honeycomb elements, and / or diffractive optical elements may be used in the pupil-forming optical unit 8. The pupil plane 9 is optically conjugate with a further pupil plane 10 of a projection lens 11 of the projection exposure apparatus 1. The projection lens 11 is arranged downstream of the illumination optical unit 5 between the object plane 6 and the image plane 12. A wafer 13 is arranged in the image plane 12 and is illustrated in FIG. 1 by a dashed line. The wafer 13 is carried by a not-described holder that allows controlled scanning or stepwise displacement. An object field 14 in the object plane 6 is imaged by the projection lens 11 onto an image field 14a in the image plane 12.

[0028] A field lens element group 15 as a further main optical group of the illumination optical unit 5 is located downstream of the pupil plane 9, which is arranged behind the pupil forming optical unit 8. An intermediate image plane 16, conjugate with the object plane 6, is arranged behind the field lens element group 15. The field lens element group 15 is therefore a condenser group. At the intermediate image plane 16 there is a diaphragm 17 for presetting the peripheral boundary of the object field 14. The diaphragm 17 is also called a REMA diaphragm (reticle masking system for narrowing the reticle 7).

[0029] The intermediate image plane 16 is imaged to the object plane 6 by a lens group 18, also referred to as a REMA lens element group or REMA lens, which constitutes a further main optical group of the illumination optical unit 5. The lens group 18 is a color-corrected imaging illumination optical unit.

[0030] A further pupil plane 19 is between the field planes 16 and 6 .

[0031] FIG. 2 shows a meridional section through an embodiment of an imaging illumination optical unit 20 which can be used in the projection exposure apparatus 1 as a REMA lens instead of the lens group 18 .

[0032] The illumination optical unit 20 functions to image the illumination adjustment field 16a in the intermediate image plane 16 preset by the diaphragm 7 into the object field 14 of the downstream projection optical unit 11 in a manner compatible with the downstream projection optical unit 11.

[0033] 2 illustrates the trajectories of the respective main beams 21 and peripheral pupil-bounding beams 22, starting from two spaced-apart field points. This depicts the imaging beam path of the illumination light 4.

[0034] The illumination optical unit 20 has, in the imaging beam path 23 between the illumination adjustment field 16a and the object field 14, a total of nine lens elements L1 to L9 numbered in the order in which they impinge on the imaging beam path 23.

[0035] Lens elements L1 and L2 form, in the vicinity of the adjusted field of view 16a, a condenser lens element group of the illumination optical unit 20. The lens elements of this condenser lens element group of the illumination optical unit 20 are made of the same lens element material.

[0036] The lens elements L3 to L6 form a lens element group near the pupil plane 19, which is close to the pupil of the illumination optical unit 20.

[0037] Lens elements L7-L9 form a field lens element group of illumination optical unit 20 in the vicinity of object field .

[0038] In front of the object field 14, the gradation filter F of the illumination optical unit 20 is located downstream of the lens element L9. The gradation filter F is a static neutral density filter with an absorbing layer. The gradation filter F ensures uniformity of the illumination intensity of the object field 14 or image field 14a.

[0039] The illumination optical unit 20 has a total transmittance for the illumination light 4 of at least 90.0%.

[0040] The illumination optical unit 20 is designed for illumination light 4 having a wavelength of 365 nm.

[0041] The illumination optical unit 20 is of refractive design and does not have any mirrors that have a beam-influencing effect. In the described embodiment, the illumination optical unit 20 does not actually have any plane deflection mirrors either. There is space for such a plane deflection mirror between lenses L6 and L7, so that in further embodiments of the illumination optical unit that include such a plane deflection mirror, the imaging beam path 23 may be folded.

[0042] The lens elements L3-L5 form a triplet 24. The lens element L4 of the triplet between them has a biconcave design and is fitted between the two convex lens element surfaces of each of the adjacent lens elements L3 and L5 of the triplet. This alignment is such that, with respect to coordinate areas za and zb of the beam path coordinates along the optical axis 2 of the illumination optical unit 20, planes perpendicular to the optical axis 2 in the respective coordinate areas za and zb (the respective xy planes at the area boundaries za and zb are illustrated by dashed lines in FIG. 2) intersect both the biconcave lens element L4 and one of the adjacent lens elements L3 and L5 of the triplet 24. The two coordinate areas, za where the lens elements L4 and L3 intersect and zb where the lens elements L4 and L5 intersect, are spaced apart from each other along the optical axis 2. The coordinate areas za and zb have an extent along the optical axis 2 in the range of 1 mm to 50 mm, in particular in the range of 5 mm to 25 mm. The coordinate area za extends within an area of ​​20 mm. The coordinate area zb extends within an area of ​​5 mm.

[0043] Illumination optical unit 20 provides a 4x magnification between adjusted field of view 16a and object field 14.

[0044] The object field 14 has a diameter of approximately 120 mm, corrected for imaging aberrations. The diameter of the object field 14, corrected for imaging aberrations, is greater than 10 mm, greater than 25 mm, greater than 50 mm, and greater than 100 mm.

[0045] The distance between the intermediate image plane 16 and the object plane 6 is 1200 mm.

[0046] Lens elements L1, L2, L3, L5, L6, L7, and L8 are made of crown glass (FK5) having a refractive index in the range of 1.50 at the illumination light wavelength. Lens elements L4 and L9 are made of flint glass (LLF1) having a refractive index in the range of 1.58 at the illumination light wavelength. Lens elements L1 to L9 of illumination optical unit 20 are made of exactly two different lens element materials, in particular one crown glass and one flint glass.

[0047] The following table shows the design data for the illumination optical unit 20 according to FIG.

[0048] In the first column, the first table for FIG. 2 shows the optical surfaces of the illumination optical unit numbered from left to right.

[0049] “Surfaces 1 and 2” form an intermediate image surface 16 .

[0050] "Surfaces 3 and 4" describe the entrance and exit surfaces of lens element L1.

[0051] "Surfaces 5 and 6" describe the entrance and exit surfaces of lens element L2. The exit surface of lens element L2 is in the form of an aspheric surface, the aspheric coefficients of which are given by the aspheric formula p(h)=[((1 / r)h 2 ) / (1+SQRT(1-(1+K)(1 / r) 2 h 2 ))]+C1·h 4 +C2·h 6 +... As tabulated in Table 2 for FIG.

[0052] "Surfaces 7 and 8" describe the entrance and exit surfaces of lens element L3.

[0053] "Surfaces 9 and 10" describe the entrance and exit surfaces of lens element L4.

[0054] "Surfaces 11 and 12" describe the entrance and exit surfaces of lens element L5. The entrance surface of lens element L5, in turn, is in the form of an aspheric surface, the aspheric coefficients of which are tabulated in Table 3 for FIG. 2.

[0055] "Surface 13" describes the location of the plane relative to the pupil stop, i.e., pupil plane 19. In illumination optical unit 20, pupil plane 19 is between lens elements L5 and L6.

[0056] "Surfaces 14 and 15" describe the entrance and exit surfaces of lens element L6. The exit surface of lens element L6, in turn, is in the form of an aspheric surface, the aspheric coefficients of which are tabulated in Table 4 for FIG. 2.

[0057] "Surface 16" illustrates a possible placement location for a plane deflection mirror not illustrated in FIG.

[0058] "Surfaces 17 and 18" describe the entrance and exit surfaces of lens element L7. The entrance surface of lens element L7, in turn, is in the form of an aspheric surface, the aspheric coefficients of which are tabulated in Table 5 for FIG. 2.

[0059] "Surfaces 19 and 20" describe the entrance and exit surfaces of lens element L8.

[0060] "Surface 21 and surface 22" describe the entrance and exit surfaces of lens element L9. The exit surface of lens element L9, in turn, is in the form of an aspheric surface, the aspheric coefficients of which are tabulated in Table 6 for FIG. 2.

[0061] "Surfaces 23 and 24" describe the entrance and exit faces of a graduated filter F similarly made of crown glass.

[0062] "Faces 25 and 26" describe the entrance and exit faces of reticle 7, which has a substrate of fused silica (Suprasil).

[0063] Lens elements L1 to L9 are rotationally symmetric about optical axis 2. A total of five of the nine lens elements are in the form of aspherical lens elements. In each of these five aspherical lens elements, in each case exactly one of the two optical surfaces is in the form of an aspherical surface, the other one of the two optical surfaces of the respective lens element is in the form of a spherical surface.

[0064] The illumination optical unit 20 does not have an intermediate image plane. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6]

[0065] With reference to Figure 3, a description of a further embodiment of an illumination optical unit 25 which can be used instead of the illumination optical unit 20 as a REMA lens in the projection exposure apparatus 1 is given below. Components and functions which correspond to components and functions already described above with reference to Figures 1 and 2, in particular with reference to Figure 2, have the same reference numerals and will not be discussed in detail again.

[0066] The illumination optical unit 25 has a total of ten lens elements L1 to L10. A gradation filter F is then placed in the imaging beam path 23 between the last lens element L10 and the reticle 7.

[0067] The illumination optical unit 25 has a total transmittance of 90.0%.

[0068] Lens elements L1, L5, and L10 are made of flint glass (LLF1), and the other lens elements L2-L4 and L6-L9 are made of crown glass (FK5).

[0069] The lens elements L1 to L3 form a group of condenser lens elements of the illumination optical unit 25 in the vicinity of the adjusted field of view 16a.

[0070] The lens elements L4 to L8 form a lens element group near the pupil plane 19 of the illumination optical unit 25.

[0071] Lens elements L9 and L10 form a field lens element group near object field 14.

[0072] Lens elements L4 and L5 form a doublet 24a of lens elements. Concave lens element L5 is fitted to the adjacent convex lens element surface of lens element L4 of the doublet such that, for a coordinate area za, it then holds that a plane perpendicular to the optical axis 2 of the illumination optical unit 25 in this coordinate area za intersects both the concave lens element L5 of the doublet and the adjacent lens element L4.

[0073] In the illumination optical unit 25, there are also two different lens element materials in the case of the condenser lens element group L1-L3.

[0074] The optical design data for the illumination optical unit 25 is provided by the following design tables, which correspond in structure to the tables for FIG.

[0075] The exit surface of lens element L1, the entrance surface of lens element L6, the entrance surface of lens element L9, and the exit surface of lens element L10 are aspheric in form, and their aspheric coefficients are tabulated in Tables 2-5 for FIG.

[0076] Next, there is a space between lens elements L8 and L9 for the planar deflection mirror, which is reported as "Surface 20" in Table 1 for FIG. 3, for example.

[0077] In Table 1 for Figure 3, pupil plane 19, where the pupil stop may be located, is reported as "Surface 15." In illumination optical unit 25, pupil plane 19 is between lens elements L6 and L7.

[0078] "Faces 27 and 28" then represent the locations of the entrance and exit faces of reticle 7. [Table 7] [Table 8] [Table 9] [Table 10] [Table 11]

[0079] With reference to Figure 4, a description of a further embodiment of an illumination optical unit 26 which can be used instead of the illumination optical unit 20 as a REMA lens in the projection exposure apparatus 1 is given below. Components and features which correspond to components and features already described above with reference to Figures 1 to 3, in particular with reference to Figures 2 and 3, have the same reference numerals and will not be discussed in detail again.

[0080] The illumination optical unit 26 has a total of 11 lens elements L1 to L11. zA plane deflection mirror M, which deflects the light by 90°, is disposed between lens elements L9 and L10.

[0081] Lens elements L1-L3 form a condenser lens element group of illumination optical unit 26. Lens elements L7-L9 form a pupil-proximal lens element group of illumination optical unit 26. Pupil plane 19 is located just before lens element L7 in the imaging beam path.

[0082] Between these lens element groups is a lens element group including lens elements L4-L6, which in turn form a lens element triplet including a biconcave lens element L5, which is fitted between the two convex lens elements L4 and L6 such that the cross-sectional coordinate area za, zb is then generated in accordance with what was described above in relation to FIG. 2.

[0083] Lens elements L1, L5, L7, L10, and L11 are made of flint glass (LLF1), while lens elements L2-L4, L6, L8, and L9 are made of crown glass (FK5).

[0084] The illumination optical unit 26 has a total transmittance of 88.5%.

[0085] The following table shows the design data for the illumination optical unit 26 according to FIG.

[0086] The exit surface of lens element L1, the entrance surface of lens element L7, and the exit surface of lens element L11 are aspheric in shape, and their coefficients are tabulated in Tables 2-4 of FIG.

[0087] In Table 1 for FIG. 4, “plane 15” describes pupil plane 19 .

[0088] "Surface 22" depicts the placement surface for mirror M.

[0089] "Faces 29 and 30" denote the entrance and exit faces of reticle 7. [Table 12] [Table 13] [Table 14] [Table 15]

[0090] With reference to Figure 5, a description of a further embodiment of an illumination optical unit 27 which can be used instead of the illumination optical unit 20 as a REMA lens in the projection exposure apparatus 1 is given below. Components and features which correspond to components and features already described above with reference to Figures 1 to 4, in particular with reference to Figures 2 and 4, have the same reference numerals and will not be discussed in detail again.

[0091] The illumination optical unit 27 has a total of 11 lens elements L1 to L11.

[0092] Lens elements L1-L3 form a condenser lens element group, lens elements L4-L9 form a near-pupil lens element group, and lens elements L10 and L11 form a field lens element group.

[0093] Lens element L1 is made of silica glass (SILUV) with high ultraviolet transmittance. Lens elements L2-L4, L7, L9, and L11 are made of crown glass (FK5). Lens elements L5, L6, L8, and L10 are made of flint glass (LLF1).

[0094] Overall, the lens elements L1 to L11 of the illumination optical unit 27 are therefore made of three different materials.

[0095] A 90° turning mirror M is positioned between lens elements L9 and L10.

[0096] The illumination optical unit 27 has a total transmittance of 88.1%.

[0097] The following table shows the design data for the illumination optical unit 27 according to FIG.

[0098] The fused silica material of lens element L1 has a refractive index of approximately 1.47 at the wavelength of the illumination light.

[0099] The entrance surface of lens element L2, the entrance surface of lens element L9, and the exit surface of lens element L11 are aspheric in form, and their coefficients are shown in Tables 2-4 for FIG.

[0100] In Table 1, “Surface 17” represents pupil surface 19.

[0101] In Table 1, "Surface 22" represents the 90° deflection mirror M.

[0102] "Faces 29 and 30" represent the entrance and exit faces of reticle 7.

[0103] Lens elements L8 and L8 then form a doublet having a cross-sectional plane coordinate area za in accordance with what has been described above, particularly in relation to FIG. [Table 16] [Table 17] [Table 18] [Table 19]

[0104] With reference to Figure 6, a description of a further embodiment of an illumination optical unit 28 which can be used instead of the illumination optical unit 20 as a REMA lens in the projection exposure apparatus 1 is given below. Components and features which correspond to components and features already described above with reference to Figures 1 to 5, in particular with reference to Figures 2 and 5, have the same reference numerals and will not be discussed in detail again.

[0105] The illumination optical unit 28 has a total of 11 lens elements L1 to L11.

[0106] Lens elements L1-L5 form a condenser lens element group. Lens elements L7-L9 form a near-pupil lens element group. Lens elements L10 and L11 form a field lens element group. Lens elements L3-L5 then form a lens element triplet having two cross-sectional coordinate areas za, zb, in accordance with what has been described above, particularly in relation to FIG. 2.

[0107] Lens elements L1-L11 of illumination optical unit 28 are therefore made of two different lens element materials: quartz glass (SILUV) with high ultraviolet transmittance, and flint glass (LLF1) for lens elements L4, L6, and L9.

[0108] The illumination optical unit 28 has a total transmittance of 91.4%.

[0109] The pupil surface 19 is located between lenses L7 and L8, which form a quartz glass doublet. In combination with these, the following lens element L9 forms a narrowing lens element group in front of the deflection mirror M, which leads to a narrowing of the diameter of the total beam in the imaging beam path 22 by at least 25% compared to the maximum diameter of the total beam in the imaging beam path 22 before the narrowing. In the illumination optical unit 28, the maximum narrowing of the total beam is at the exit surface of lens element L9, which results in a narrowing of approximately 27% compared to the maximum diameter of the total beam present in the region of the pupil surface 19. This narrowing of the total beam reduces the size requirements for the deflection mirror M.

[0110] The following table shows the design data for the illumination optical unit 28 according to FIG.

[0111] The exit surfaces of lens element L2, lens element L8, and lens element L10 are aspheric in form, and their coefficients are shown in Tables 2-4 for FIG.

[0112] A deflecting mirror M is located between lens elements L9 and L10. [Table 20] [Table 21] [Table 22] [Table 23]

[0113] The etendue of the illumination optical unit described above is 820 mm 2 Depending on the embodiment of the illumination optical unit, the etendue is 700 mm 2 sr~1200mm 2 Another value in the range of sr, e.g., 750 mm 2 sr, 950mm 2 sr, or 1000mm 2 It may also have sr.

[0114] The point image quality lies in a spot diameter of less than 400 μm. To verify the point image quality, the generated point image is measured by the energy distribution of the imaging light sub-beams originating from the associated object point. The diameter of the point image is defined by the fact that 99.9% of the measured optical power of the imaging light sub-bundles lies within a point image circle having a diameter of the respective point image quality, i.e., a circle having a diameter of less than 400 μm in the presented case. The center point of each circle is the point at which the respective main beam originating from the assigned object point passes through the image plane 12 at a reference wavelength of 365.5 nm in the presented case.

[0115] Using the projection exposure apparatus 1, at least a part of the reticle 7 is imaged onto an area of ​​a photosensitive layer on the wafer 13 for the lithographic production of micro- or nanostructured components. Depending on whether the projection exposure apparatus 1 is in the form of a scanner or a stepper, the reticle 7 and the wafer 13 are moved in the y-direction synchronously in time, either continuously in a scanner operation or stepwise in a stepper operation.

Claims

1. A color-corrected imaging illumination optical unit (18; 20; 25; 26; 27; 28) for use in a lithographic projection exposure apparatus (1), comprising: the illumination optical unit (18; 20; 25; 26; 27; 28) is used to image the illumination-controlled field (16 a) into an object field (14) of a downstream projection optical unit (11) via an imaging beam path (23) in a manner adapted to the downstream projection optical unit (11), the illumination optical unit (18; 20; 25; 26; 27; 28) has at least seven and at most twelve lens elements (L1-L9; L1-L10; L1-L11) in the imaging beam path (23), The illumination optical unit (18; 20; 25; 26; 27; 28) is a color-corrected imaging illumination optical unit having a total transmittance for illumination light of at least 85%.

2. 2. The illumination optical unit according to claim 1, characterized in that at least three of the lens elements are in the form of aspherical lens elements (L2, L5, L6, L7, L9; L1, L6, L9, L10; L1, L7, L11; L2, L9, L11; L2, L8, L10).

3. 3. The illumination optical unit according to claim 1 or 2, characterized in that it is designed for illumination light (4) having a wavelength of 365 nm.

4. Illumination optical unit according to any one of claims 1 to 3, characterized by a refractive design of the beam-influencing parts (L1-L9; L1-L10; L1-L11) of the illumination optical unit.

5. 5. The illumination optical unit according to claim 1, wherein the lens elements (L1-L9; L1-L10; L1-L11) of the illumination optical unit (18; 20; 25; 26; 27; 28) are made from up to three different lens element materials.

6. 6. The illumination optical unit according to claim 1, characterized in that the concave lens element (L5; L8) is fitted into a convex lens element surface of the adjacent lens element (L4; L9) of the doublet in such a way that, for at least one specific coordinate region (za) of a beam path coordinate (z) along the optical axis (2) of the illumination optical unit (25; 27), a plane (xy) perpendicular to the optical axis (2) within the coordinate region (za) intersects both the concave lens element (L5; L8) and the adjacent lens element (L4; L9) of the doublet.

7. 6. The illumination optical unit according to claim 1, characterized in that a triplet (24a) of lens elements (L4, L5; L4, L3) is fitted to a convex lens element surface of an adjacent lens element (L4; L3) of the doublet in such a way that, for at least one specific coordinate region (za) of a beam path coordinate (z) along an optical axis (2) of the illumination optical unit (20; 26), a plane (xy) perpendicular to the optical axis (2) within the coordinate region (za) intersects both the concave lens element (L5; L4) of the doublet and the adjacent lens element (L4; L3).

8. 8. The illumination optical unit according to claim 7, characterized in that for two distinct coordinate regions (za, zb) of a beam path coordinate (z) along the optical axis (2) of the illumination optical unit (20; 26; 28) spaced apart from each other along the optical axis (2), it holds that a plane (xy) lying in the coordinate region (za, zb) intersects both a biconcave lens element (L4; L5; L4) of the triplet (24) and one of the adjacent lens elements (L3, L5; L4, L6; L3, L5).

9. 9. The illumination optical unit according to claim 1, characterized in that it comprises at least one plane deflection mirror (M), and in that the constriction of the diameter of the total beam is effected in the imaging beam path (23) upstream of the deflection mirror (M) by at least 25% compared to the maximum diameter of the total beam in the imaging beam path (23) upstream of the constriction.

10. 10. Illumination optical unit according to any one of claims 1 to 9, characterized by a magnification effect of at least a factor of 2 between the illumination adjustment field (16a) and the object field (14).

11. An optical system comprising an illumination optical unit according to any one of claims 1 to 10 and a projection optical unit (11) for imaging the object field (14) into an image field (14a).

12. An illumination system comprising an illumination optical unit according to any one of claims 1 to 10, a light source (3), and an entrance illumination optical unit (5) for illuminating the illumination-controlled field (14a).

13. 13. A projection exposure apparatus (1), comprising an illumination system according to claim 12, and comprising a projection optical unit (11) for imaging the object field (14) into an image field (14a).

14. A method for manufacturing a structured part, comprising the following steps: providing a wafer (13) at least partially affixed with a layer made of a photosensitive material; providing a reticle (7) having a structure to be imaged; Providing a projection exposure apparatus (1) according to claim 13, projecting at least a portion of the reticle (7) onto an area of ​​the layer of the wafer (13) using the projection exposure apparatus (1); A method comprising:

15. A structured component produced by the method of claim 14.

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