Imaging optical system and projection exposure installation for microlithography with an imaging optical system of this type

Abstract

An imaging optical system has a plurality of mirrors which image an object field in an object plane in an image field in an image plane. The imaging optical system has a pupil obscuration. The last mirror in the beam path of the imaging light between the object field and the image field has a through-opening for the passage of the imaging light. A penultimate mirror of the imaging optical system in the beam path of the imaging light between the object field and the image field has no through-opening for the passage of the imaging light. The result is an imaging optical system that provides a combination of small imaging errors, manageable production and a good throughput for the imaging light.

Claims

1. An imaging optical system, comprising: a plurality of mirrors configured to image an object field in an object plane into an image field in an image plane along a beam path of imaging light, wherein: the last mirror in the beam path of the imaging light between the object field and the image field has a through-opening to pass the imaging light; the penultimate mirror in the beam path of the imaging light between the object field and the image field is outside an imaging light bundle in front of the imaging field; and a reflective face of the penultimate mirror within an optically used region of the penultimate mirror has no through-opening to pass the imaging light.

2. The imaging optical system of claim 1, wherein a working spacing of the penultimate mirror in the beam path of the imaging light between the object field and the image field of the imaging light is at least 20 mm.

3. The imaging optical system of claim 1, wherein an angle of incidence of the imaging light on the penultimate mirror is at most 35.

4. The imaging optical system of claim 1, comprising an imaging beam path section between a third to last mirror in the beam path of the imaging light between the object field and the image field and the penultimate mirror in the beam path of the imaging light between the object field and the image field, wherein a portion of the imaging beam path in front of the imaging beam path section and an imaging light bundle in a region of the image field are guided on opposing sides of the imaging beam path section, respectively.

5. The imaging optical system of claim 1, comprising an imaging beam path section between a third to last mirror in the beam path of the imaging light between the object field and the image field and the penultimate mirror in the beam path of the imaging light between the object field and the image field, wherein a portion of the imaging beam path in front of the imaging beam path section and an imaging light bundle in a region of the image field are guided on the same side of the imaging beam path section.

6. The imaging optical system of claim 1, wherein a third to last mirror in the beam path of the imaging light between the object field and the image field and a sixth to last mirror in the beam path between the object field and the image field are arranged back to back.

7. The imaging optical system of claim 1, comprising an intermediate image in the beam path of the imaging light between the object field and the image field.

8. The imaging optical system of claim 1, comprising an intersection region between imaging beam path sections.

9. The imaging optical system of claim 1, wherein the imaging optical system has a numerical aperture of at least 0.3.

10. The imaging optical system of claim 1, wherein the image field is a rectangular field.

11. The imaging optical system of claim 1, wherein the imaging optical system is a microlithography projection optical system.

12. A projection exposure installation, comprising: an illumination system; and a projection optical system comprising the imaging optical system of claim 1, wherein the projection exposure apparatus is a microlithography projection exposure apparatus.

13. A method, comprising: providing a microlithography projection exposure comprising: an illumination system; and a projection optical system comprising the imaging optical system of claim 1; and using the projection exposure installation to project a structure on a reticle onto a light-sensitive layer of the wafer.

14. The imaging optical system of claim 1, wherein only the last mirror in the beam path of the imaging light between the object field and the image field has a reflective surface that surrounds a through-opening to pass the imaging light.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An embodiment of the disclosure will be described in more detail below with the aid of the drawings, in which:

(2) FIG. 1 schematically shows a projection exposure installation for EUV microlithography;

(3) FIG. 2 shows, in a meridional section, an embodiment of an imaging optical system, which can be used as a projection lens system in the projection exposure installation according to FIG. 1, the imaging beam path being shown (virtually) for the main beams and being shown for the upper and lower coma beam of a plurality of selected field points;

(4) FIGS. 3 to 21 show further embodiments of the imaging optical system in a view similar to FIG. 2.

DETAILED DESCRIPTION

(5) A projection exposure installation 1 for microlithography has a light source 2 for illumination light or imaging light 3. The light source 2 is an EUV light source which produces light in a wavelength range of, for example, between 5 nm and 30 nm, in particular between 5 nm and 15 nm. The light source 2 may, in particular, be a light source with a wavelength of 13.5 nm or a light source with a wavelength of 6.9 nm. Other EUV wavelengths are also possible. In general, any wavelengths, for example visible wavelengths or else other wavelengths, which can be used in microlithography and are available for the suitable laser light sources and/or LED light sources (for example 365 nm, 248 nm, 193 nm, 157 nm, 129 nm, 109 nm), are even possible for the illumination light 3 guided in the projection exposure installation 1. A beam path of the illumination light 3 is shown extremely schematically in FIG. 1.

(6) An illumination optical system 6 is used to guide the illumination light 3 from the light source 2 to an object field 4 in an object plane 5. The object field 4 is imaged in an image field 8 in an image plane 9 with the predetermined reduction scale using a projection optical system or an imaging optical system 7. The image field 8, in the x-direction, has an extent of 26 mm and, in the y-direction, an extent of 2 mm. The object field 4 and the image field 8 are rectangular. One of the embodiments shown in FIG. 2 ff. can be used for the projection optical system 7. The projection optical system 7 according to FIG. 2 reduces by a factor of 4. Other reduction scales are also possible, for example 5, 8 or else reduction scales which are greater than 8. The image plane 9, in the projection optical system 7 in the embodiments according to FIG. 2 ff. is arranged parallel to the object plane 5. Imaged here is a portion, which coincides with the object field 4, of a reflection mask 10, which is also called a reticle.

(7) The imaging by the projection optical system 7 takes place on the surface of a substrate 11 in the form of a wafer, which is carried by a substrate holder 12. FIG. 1 schematically shows, between the reticle 10 and the projection optical system 7, a beam concentration 13 of the illumination light 3 running therein, and, between the projection optical system 7 and the substrate 11, a beam concentration 14 of the illumination light 3 leaving the projection optical system 7. A numerical aperture (NA) on the image field side of the projection optical system 7 in the embodiment according to FIG. 2 is 0.50. This is not represented to scale in FIG. 1.

(8) To facilitate the description of the projection exposure installation 1 and the various embodiments of the projection optical system 7, a Cartesian xyz-coordinate system is given in the drawing, from which the respective position reference of the components shown in the figures emerges. In FIG. 1, the x-direction runs perpendicular to the plane of the drawing and into it. The y-direction extends to the right and the z-direction downward.

(9) The projection exposure installation 1 is of the scanner type. Both the reticle 10 and the substrate 11 are scanned during operation of the projection exposure installation 1 in the y-direction. A stepper type of the projection exposure installation 1, in which a stepwise displacement of the reticle 10 and the substrate 11 in the y-direction takes place in between individual exposures of the substrate 11, is possible.

(10) FIG. 2 shows the optical design of a first embodiment of the projection optical system 7. FIG. 2 shows the beam path of three respective individual beams 15, which issue from five object field points spaced apart from one another in the y-direction in FIG. 2. The three individual beams 15, which belong to one of these five object field points, are in each case associated with three different illumination directions for the two object field points. Main beams 16, which run through the centre of a pupil in a pupil plane 17 of the projection optical system 7, are drawn in FIG. 2 only for graphical reasons as these are not real, but virtual imaging beam paths of the projection optical system 7 because of a central pupil obscuration of the projection optical system 7. These main beams 16 firstly run divergently, proceeding from the object plane 5. This is also called a negative back focal distance of an entry pupil of the projection optical system 7 below. The entry pupil of the projection optical system 7 according to FIG. 2 is not located within the projection optical system 7, but in the beam path in front of the object plane 5. This makes it possible, for example, to arrange a pupil component of the illumination optical system 6 in the entry pupil of the projection optical system 7 in the beam path in front of the projection optical system 7, without further imaging optical components having to be present between this pupil component and the object plane 5.

(11) The projection optical system 7 according to FIG. 2 has a total of six mirrors, which are numbered consecutively by M1 to M6 in the order of their arrangement in the beam path of the individual beams 15, proceeding from the object field 4. FIG. 2 shows the calculated reflection faces of the mirrors M1 to M6 or M5, M6. Only a small region of these calculated reflection faces is used, as can be seen in the view of FIG. 2. Only this actually used region of the reflection faces is actually present in the real mirrors M1 to M6. These useful reflection faces are carried in a known manner by mirror bodies.

(12) All six mirrors M1 to M6 of the projection optical system 7 are designed as free-form faces which cannot be described by a rotationally symmetrical function. Other embodiments of the projection optical system 7 are also possible, in which at least one of the mirrors M1 to M6 has a free-form reflection face of this type.

(13) A free-form face of this type may also be produced from a rotationally symmetrical reference face. Free-form faces of this type for reflection faces of the mirrors of projection optical systems of projection exposure installation for microlithography are known from US 2007-0058269 A1.

(14) The free-form face can be described mathematically by the following equation:

(15) $\begin{array}{cc}Z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-\left(1+k\right)c^2{r}^2}}+\underset{j=2}{\overset{N}{.Math.}}{C}_j{X}^m{Y}^n& \left(1\right)\end{array}$
wherein there applies:

(16) $\begin{array}{cc}j=\frac{{\left(m+n\right)}^2+m+3n}{2}+1& \left(2\right)\end{array}$
Z is the rising height (sagitta) of the free-form face at the point x, y
(x.sup.2+y.sup.2=r.sup.2).
c is a constant, which corresponds to the vertex curvature of a corresponding asphere. k corresponds to a conical constant of a corresponding asphere. C.sub.j are the coefficients of the monomials X.sup.mY.sup.n. Typically, the values of c, k and C.sub.j are determined on the basis of the desired optical properties of the mirror within the projection optical system 7. The order of the monomial, m+n, may be varied as desired. A monomial of a higher order may lead to a design of the projection optical system with improved image error correction, but is more complex to calculate. m+n may adopt values of between 3 and more than 20.

(17) Free-form faces can also be described mathematically by Zernike polynomials, which are described, for example, in the manual of the optical design programme CODE V. Alternatively, free-form faces may be described with the aid of two-dimensional spline surfaces. Examples of this are Bezier curves or non-uniform rational basis splines (NURBS). Two-dimensional spline surfaces may, for example, be described by a network of points in an xy-plane and associated z-values or by these points and gradients associated with them. Depending on the respective type of spline surface, the complete surface is obtained by interpolation between the network points using, for example, polynomials or functions, which have specific properties with regard to their continuity and differentiability. Examples of this are analytical functions.

(18) The mirrors M1 to M6 have multiple reflection layers to optimise their reflection for the impinging EUV illumination light 3. The reflection can be optimised all the better, the closer the impingement angle of the individual beams 15 on the mirror surface lies to the perpendicular incidence. The projection optical system 7 has small reflection angles overall for all the individual beams 15.

(19) The optical design data of the reflection faces of the mirrors M1 to M6 of the projection optical system 7 can be inferred from the following tables. The first of these tables gives, for the optical surfaces of the optical components and for the aperture diaphragm, the respective reciprocal value of the vertex curvature (radius) and a spacing value (thickness), which corresponds to the z-spacing of adjacent elements in the beam path, proceeding from the object plane. The second table gives the coefficients C, of the monomials X.sup.mY.sup.n in the free-form face equation given above for the mirrors M1 to M6. Nradius is in this case a standardisation factor. According to the second table, the amount is still given in mm, along which the respective mirror, proceeding from a mirror reference design, has been decentred (Y-decentre) and rotated (X-rotation). This corresponds to a parallel displacement and a tilting in the free-form face design method. The displacement takes place here in the y-direction and the tilting is about the x-axis. The rotation angle is given in degrees here.

(20) TABLE-US-00001 Surface Radius Spacing value Operating mode Object plane INFINITE 815.666 M1 1153.305 615.656 REFL M2 222.516 319.520 REFL M3 382.480 319.520 REFL M4 558.747 1485.905 REFL M5 701.517 770.248 REFL M6 875.932 810.223 REFL Image plane INFINITE 0.000

(21) TABLE-US-00002 Coef- ficient M1 M2 M3 M4 M5 M6 K 2.605966E+00 5.961575E01 1.802738E+00 4.147176E01 5.283440E+00 8.773495E03 Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2 9.076785E06 2.333474E03 9.771997E05 1.351961E04 3.072793E04 3.218741E05 Y2 1.262804E05 2.351151E03 4.280681E04 2.063652E04 4.778011E05 1.825268E05 X2Y 5.547212E08 1.113508E06 1.714986E06 4.601654E08 7.454541E07 3.779820E09 Y3 7.260181E08 9.449646E07 1.271140E06 8.751761E08 2.182587E07 4.618324E09 X4 2.717367E10 5.643202E09 1.100027E10 2.753993E11 1.011144E10 1.051777E11 X2Y2 4.717758E10 1.285056E08 1.176444E08 6.509076E11 5.621785E10 2.181974E11 Y4 1.535374E10 5.716571E09 8.317888E09 1.255759E10 1.083353E10 7.220214E12 X4Y 4.620639E14 2.908858E12 2.838235E11 5.428510E14 3.027549E13 2.004008E15 X2Y3 1.354365E13 2.499768E12 4.853945E11 1.768342E14 3.032599E12 4.901143E15 Y5 9.758474E14 8.026135E12 2.371972E11 1.039111E13 6.346065E12 6.164413E15 X6 1.650739E19 1.746162E14 4.622947E14 4.561474E17 1.475643E15 4.982818E18 X4Y2 1.411917E16 4.021338E14 1.679149E13 4.396111E16 2.334912E15 7.006257E18 X2Y4 4.293001E16 3.421095E14 2.624283E13 4.785171E16 2.028609E14 2.259935E18 Y6 3.538529E16 1.283163E14 3.276365E14 9.873439E16 1.117653E14 8.963014E19 X6Y 2.078486E19 1.183867E16 3.132075E16 2.806498E19 1.669547E17 3.910845E21 X4Y3 2.392439E19 3.921710E16 1.722114E16 3.083030E19 2.773189E17 1.616941E20 X2Y5 3.774411E19 4.353032E16 4.633354E16 1.078201E18 2.004813E17 1.540131E20 Y7 7.122980E18 3.967812E17 6.639885E16 2.211631E18 8.876500E17 4.032079E21 X8 1.403258E22 5.276488E20 1.503485E18 1.126741E22 3.102183E20 3.780424E24 X6Y2 1.352342E21 5.134116E19 9.187180E18 4.302896E22 3.184593E20 4.432214E24 X4Y4 2.843591E21 8.052424E19 1.538670E17 9.478150E22 1.108150E20 1.149988E24 X2Y6 3.933427E21 2.988855E19 7.353139E18 1.034931E20 1.498632E19 1.296327E24 Y8 1.881220E20 5.733234E19 1.441529E18 2.416028E21 4.165554E19 1.440139E24 X8Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y3 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y5 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y7 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Nradius 1.000000E+00 1.000000E+00 1.000000E+00 1.000000E+00 1.000000E+00 1.000000E+00

(22) TABLE-US-00003 Coef- Image ficient M1 M2 M3 M4 M5 M6 plane Y-decentre 4.633 32.903 307.827 405.254 609.190 503.476 0.000 X-rotation 2.685 19.040 11.876 4.571 7.815 3.906 0.000

(23) The mirrors M1, M2, M4 and M6 are configured as concave mirrors. The radius of curvature of the mirror M2 is so large that it almost looks like a planar mirror in FIG. 2. The mirrors M3 and M5 are configured as convex mirrors.

(24) The mirrors M1 and M6 and M3 and M6 are arranged back to back with regard to the orientation of their reflection faces.

(25) The optically used regions of the mirrors M1 to M5 have no through-opening within the optically used region for the passage of imaging light, in other words are not obscured. The mirror M5, in other words the penultimate mirror in the beam path of the illumination light 3 between the object field 4 and the image field 8, also has no through-opening for the passage of the imaging light or illumination light 3. The mirror M5, in other words, has an uninterrupted used reflection face.

(26) In the imaging beam path between the mirrors M4 and M5, the individual beams 15 pass through a through-opening 18 in the mirror M6. The mirror M6 is used around the through-opening 18. The mirror M6 is thus an obscured mirror.

(27) The pupil plane 17, in the imaging beam path in the projection optical system 7, lies between the mirrors M2 and M3. The pupil plane 17 also lies in the imaging beam path between the object field 4 and the through-opening 18 of the mirror M6. An obscuration stop or diaphragm for central shading of a pupil of the projection optical system 7 may be arranged in the pupil plane 17. The obscuration diaphragm thus shades the central region of the imaging light 3 in the pupil plane 17 which does not contribute to the imaging of the object field 4 because of the through-opening 18.

(28) An intermediate image plane 19 of the projection optical system 7 is located in the imaging beam path between the mirrors M4 and M5. The associated intermediate image is located adjacent to the through-opening 18 in the mirror M6. As a result it is possible to make this through-opening 18 small in comparison to the used reflection face of the mirror M8. A central pupil obscuration, in other words the ratio of an area blanked by the through-opening 18 or the obscuration diaphragm in the pupil plane 17 within an exit pupil of the projection optical system 7 relative to an overall face of this exit pupil, is 4.4% in the projection optical system 7.

(29) A working spacing d.sub.w between the image plane 9 and the portion closest to the image plane of a used reflection face of the mirror M5 is 22 mm. A ratio of this working spacing d.sub.w to the overall length of the projection optical system 7, in other words to the spacing between the object field 4 and the image field 8, is 1.3%.

(30) A further pupil plane 20 of the projection optical system 7 is located in the imaging beam path in the region of the mirror M5. A diaphragm may also be arranged here.

(31) The angle of incidence of the individual beams 15 on the mirror M3 in the meridional plane, which is shown in FIG. 2, is a maximum of 34.5.

(32) An imaging beam path section 21 runs between the third to last mirror M4 in the imaging beam path and the penultimate mirror M5 in the imaging beam path. This imaging beam path section 21 begins at the reflection on the mirror M4 and ends at the reflection on the mirror M5. The imaging beam path in the projection optical system 7 in front of the imaging beam path section 21, in other words the imaging beam path between the object field 4 and the mirror M4, on the one hand, and an imaging light bundle 22 in the region of the image field 8, on the other hand, are guided on the same side of the imaging beam path section 21. Accordingly, the object field 4 and the penultimate mirror M5 are arranged on different sides of a main plane 23 which extends centrally through the image field 8 and is perpendicular to the meridional plane, in other words the plane of the drawing of FIGS. 2 to 4.

(33) FIG. 3 shows a further embodiment of the projection optical system 7. Components, which correspond to those of the projection optical system 7 according to FIG. 2, have the same reference numerals and are not discussed again in detail.

(34) The optical design data of the projection optical system 7 according to FIG. 3 can be inferred from the following tables, which correspond to the tables on the projection optical system 7 according to FIG. 2 with respect to their structure.

(35) TABLE-US-00004 Surface Radius Spacing value Operating mode Object plane INFINITE 986.270 M1 815.021 716.283 REFL M2 1692.737 1034.499 REFL M3 805.634 904.485 REFL M4 1745.655 1800.135 REFL M5 186.402 695.651 REFL M6 818.011 795.967 REFL Image plane INFINITE 0.000

(36) TABLE-US-00005 Coef- Image ficient M1 M2 M3 M4 M5 M6 plane K 1.238679E01 1.791231E+01 1.198325E+00 2.530823E01 1.020467E02 5.662681E02 X2 1.225388E04 1.219365E03 9.215303E04 2.476431E04 1.451018E03 6.707230E06 Y2 3.086233E04 3.281365E04 2.291446E04 5.508666E05 1.225948E03 2.358417E06 X2Y 3.520023E08 2.237558E06 4.383580E08 5.980784E10 1.944652E06 5.208464E10 Y3 3.914904E09 8.665292E08 3.997990E07 5.130872E09 9.275351E07 5.831866E09 X4 5.262082E11 5.336536E08 2.120561E11 2.198962E11 7.191540E09 6.478133E13 X2Y2 1.459216E10 7.004312E10 5.077070E10 1.326969E10 1.229590E08 1.283249E12 Y4 1.690794E10 3.956379E10 6.068550E10 2.595291E11 4.780182E09 3.237182E12 X4Y 2.099690E14 1.842852E11 1.225213E13 1.180341E13 1.310535E11 2.534706E15 X2Y3 3.021789E14 1.362668E11 4.690792E13 1.357904E13 1.637678E11 8.678287E16 Y5 1.894306E13 2.933573E13 6.894643E12 5.680668E14 6.265372E12 1.795660E15 X6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y3 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y5 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y7 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y3 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y5 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y7 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Nradius 1.000000E+00 1.000000E+00 1.000000E+00 0.000000E+00 1.000000E+00 1.000000E+00 Y-decentre 28.611 158.244 344.671 406.391 114.284 227.166 0.000 X-rotation 1.129 0.021 3.156 6.560 9.217 4.608 0.000

(37) In the projection optical system 7 according to FIG. 3, the mirror M5, in comparison to the projection optical system 7 according to FIG. 2, is present mirrored about the main plane 23. The penultimate mirror M5 and the object field 4 are arranged on the same side of the main plane 23. The imaging beam path between the object field 4 and the mirror M2, on the one hand, and the imaging light bundle 22 in the region of the image field 8 of the projection optical system 7 according to FIG. 3, on the other hand, are guided on different sides of the imaging beam path section 21. The imaging beam path section 21 and a further imaging beam path section 24 between the mirrors M2 and M3 intersect in the imaging beam path of the projection optical system 7 according to FIG. 3.

(38) In the projection optical system 7 according to FIG. 3, the mirror M2 is configured as a convex mirror. Because of the very large radius of curvature of the mirror M2, the latter appears virtually to be a planar mirror in FIG. 3.

(39) The intermediate image plane 19, in the projection optical system 7 according to FIG. 3, lies practically precisely at the level of the through-opening 18 in the mirror M6.

(40) The central pupil obscuration in the projection optical system 7 according to FIG. 3 is 4.0%. The working spacing d.sub.w between the image plane 9 and the portion of the used reflection face of the mirror M5 closest to the image plane is 85 mm. A radio of this working spacing d.sub.w to the overall length of the projection optical system 7 according to FIG. 3 is 3.7%. The angle of incidence of the individual beams 15 on the mirror M5 in the meridional plane, which is shown in FIG. 3, is a maximum of 16.9.

(41) FIG. 4 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 and 3 have the same reference numerals and are not discussed again in detail.

(42) The optical design data of the projection optical system 7 according to FIG. 4 can be inferred from the following tables, which correspond to the tables on the projection optical system 7 according to FIGS. 2 and 3 with regard to their structure.

(43) TABLE-US-00006 Surface Radius Spacing value Operating mode Object plane INFINITE 485.884 M1 573.309 385.884 REFL M2 856.474 1014.613 REFL M3 619.480 508.729 REFL M4 601.504 1294.117 REFL M5 256.986 685.388 REFL M6 838.548 785.387 REFL Image plane INFINITE 0.000

(44) TABLE-US-00007 Coef- Image ficient M1 M2 M3 M4 M5 M6 plane K 5.356880E02 8.027989E02 2.215137E+00 5.038784E01 4.907814E02 1.120410E01 Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2 4.675062E04 2.669898E05 1.839305E03 2.126518E04 9.700568E04 7.232599E06 Y2 1.320900E03 5.452804E04 7.818071E04 4.431611E04 8.012468E04 1.044012E05 X2Y 1.229247E06 4.121203E07 2.381957E06 9.694733E08 1.199882E06 5.510251E09 Y3 7.423640E08 8.613636E08 4.979224E08 2.077214E08 1.739231E07 1.476529E09 X4 2.550932E10 5.351417E11 1.281481E08 4.388472E11 2.188996E09 2.529523E13 X2Y2 2.178964E10 2.067816E10 8.488864E09 1.254954E10 2.292180E09 2.688243E13 Y4 8.677437E10 8.009019E10 1.878436E09 1.372181E10 1.320127E09 1.277954E12 X4Y 3.215827E13 1.670802E13 1.372762E10 4.754789E14 6.365774E12 2.679463E16 X2Y3 1.228117E12 3.874349E13 2.437182E11 1.718101E13 6.070058E12 1.679816E15 Y5 1.148542E13 2.500543E13 1.577671E12 5.427575E13 6.442309E12 1.838497E15 X6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y3 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y5 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y7 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8Y 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y3 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y5 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y7 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y9 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X8Y2 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X6Y4 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X4Y6 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 X2Y8 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Y10 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 Nradius 1.000000E+00 0.000000E+00 1.000000E+00 1.000000E+00 1.000000E+00 1.000000E+00 Y-decentre 172.287 276.185 336.270 167.562 379.550 267.210 0.000 X-rotation 3.535 5.840 10.868 13.825 9.306 4.657 0.000

(45) The imaging beam path between the intermediate image plane 19 and the image field 8, in the projection optical system 7 according to FIG. 4, corresponds to that of the projection optical system 7 according to FIG. 3.

(46) The object field 4 and the mirror M5 are arranged on different sides of the main plane 23.

(47) The mirrors M1 and M4 on the one hand, and the mirrors M3 and M6, on the other hand, in the projection optical system 7 according to FIG. 4, are arranged back to back.

(48) The mirrors M1, M3 and M6 are concave. The mirror M5 is convex. The mirrors M2 and M4 have a radius of curvature which is so great that they appear virtually to be a planar mirror in FIG. 4.

(49) In the projection optical system 7 according to FIG. 4, an aperture diaphragm may be arranged in the region of the pupil plane 17 between the mirrors M2 and M3.

(50) The central pupil obscuration, in the projection optical system 7 according to FIG. 4, is 4.0%. The working spacing d.sub.w between the image plane 9 and the portion of the used reflection face of the mirror M5 closest to the image plane is 85 mm in the projection optical system according to FIG. 4. A ratio of this working spacing d.sub.w to the overall length of the projection optical system 7 according to FIG. 4 is 4.25%. The angle of incidence of the individual beams 15 on the mirror M5 in the meridional plane, which is shown in FIG. 4, is a maximum of 15.9.

(51) In the following table, characteristics of the projection optical system

(52) (PO) according to FIGS. 2, 3 and 4 are summarised again:

(53) TABLE-US-00008 PO accord- PO accord- PO accord- ing to ing to ing to FIG. 2 FIG. 3 FIG. 4 NA 0.5 0.5 0.5 Image field size 2 26 2 26 2 26 y times x [mm mm] Reduction scale 4 4 4 Pupil obscuration 4.4 4.0 4.0 (exit pupil) [%] Overall length [mm] 1726 2300 2000 max. angle of incidence of 28.8 10.2 11.5 the central main beam [] max. angle of incidence in 34.5 16.9 15.9 the meridional section Main beam angle in the 8 8 8 reticle for central field point [] Spacing of the centre of 22 85 85 the mirror M5 from the image plane [mm]

(54) The main beam is the main beam 16 of a central point of the object field 4. This central point is defined as the point which is located in the centre between the two edge object field points in the meridional section.

(55) FIG. 5 shows a further embodiment of the projection optical system 7. Components, which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 4 have the same reference numerals and are not discussed again in detail.

(56) The imaging beam path between the object field 4 and the image field 8 in the projection optical system 7 according to FIG. 5 is reminiscent of the imaging beam path of the embodiment according to FIG. 4. In comparison to the imaging beam path of the configuration according to FIG. 4, that according to FIG. 5 with regard to the guidance of the imaging beams between the object field 4 and the mirror M4, appears mirrored about a plane lying virtually parallel to the xz-plane. In the imaging beam path of the projection optical system 7 according to FIG. 5, a part of the imaging beam path adjacent to the mirror M3 lies on the same side of the imaging beam path section 21 as the imaging light bundle 22 in the region of the image field 8. In the embodiment according to FIG. 5, a pupil plane 17 lies in the imaging beam path between the mirrors M2 and M3 and an intermediate image plane 19 lies between the mirrors M4 and M5.

(57) The projection optical system 7 according to FIG. 5 has a numerical aperture NA on the image side of 0.33. The image field 8 has an extent of 26 mm in the x-direction and of 2.5 mm in the y-direction. The image field 8 is rectangular. A wave front error of the projection optical system 7 according to FIG. 5 is in the region between 0.2 and 0.5 (rms, Root Mean Square). This wave front error is given for a wavelength , of 13.5 nm.

(58) FIG. 6 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 5 have the same reference numerals and will not be discussed again in detail.

(59) The imaging beam path between the object field 4 and the image field 8 in the projection optical system 7 according to FIG. 6 is comparable to the imaging beams path in the embodiment according to FIG. 5. The numerical aperture on the image side and the image field size and the image field form correspond to that which was described above in conjunction with the embodiment according to FIG. 5.

(60) The projection optical system 7 according to FIG. 6 has a numerical aperture NA on the image side of 0.33. The image field 8 has an extent of 26 mm in the x-direction and 2.5 mm in the y-direction. The image field 8 is rectangular.

(61) The projection optical system 7 according to FIG. 6 has an overall length of 1180 mm between the object plane 5 and the image plane 9.

(62) The pupil plane 17 in the imaging beam path between the mirrors M2 and M3 is accessible from all sides in the embodiment according to FIG. 6.

(63) A maximum angle of incidence on the mirror M4 may be 21 in the embodiment according to FIG. 6. The angle of incidence is a maximum angle of incidence here on the mirror M4 in the plane of the drawing of FIG. 6.

(64) FIG. 7 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 6 have the same reference numerals and will not be discussed again in detail.

(65) In the projection optical system 7 according to FIG. 7, the imaging beam path between the object field 4 and the mirror M4 in total runs on the side of the imaging beam path section 21 opposing the imaging light bundle 22 between the mirrors M4 and M5.

(66) In the imaging beam path of the embodiment according to FIG. 7, no overall intersecting imaging beam path sections are present between the object field 4 and the mirror M4. The fact that individual beams of the imaging beam path sections intersect in the reflection path during the reflection on the mirrors M1 to M4 does not represent intersecting imaging beam path sections overall of the imaging beam path.

(67) An imaging beam path section 25 extending between the mirrors M3 and M4 is guided past the mirror M6 in the embodiment according to FIG. 7. A further intermediate image plane 26 in the imaging beam path section 25 lies in the region of this guiding past. The projection optical system 7 according to FIG. 7 thus has, in addition to the intermediate image plane 19, which lies close to the through-opening 18 in the imaging beam path, the further intermediate image plane 26. Thus, two intermediate images are present in the imaging beam path between the object field 4 and the image field 8 in the projection optical system 7 according to FIG. 7.

(68) FIG. 8 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 7 have the same reference numerals and will not be discussed again in detail.

(69) In the projection optical system 7 according to FIG. 8, a portion of the imaging beam path associated with the reflection on the mirror M3 is guided on the side of the imaging beam path section 21 opposing the imaging light bundle 22.

(70) An intermediate image plane 26 lies in an imaging beam path section 27 between the mirrors M1 and M2. The second intermediate image plane 19 is arranged, as in the above-described embodiments, in the region of the through-opening 18.

(71) In the imaging beam path of the embodiment according to FIG. 8, the imaging beam path section 24 between the mirrors M2 and M3, intersects an imaging beam path section 28 between the object field 4 and the mirror M1 in a first intersection region 29. The imaging beam path section 21 between the mirror M4 and M5 in turn intersects the imaging beam path section 24 between the mirrors M2 and M3 in a further intersection region 30.

(72) The projection optical systems according to FIGS. 8 to 17 may have a numerical aperture NA of 0.33. An image field size of these projection optical systems may be 2.5 mm in the x-direction and 26 mm in the y-direction.

(73) FIG. 9 shows a further embodiment of the projection optical system 7. Components which correspond to those which were already described above with reference to the projection optical system 7 from FIGS. 2 to 8 have the same reference numerals and will not be discussed again in detail.

(74) The imaging beam path in the embodiment of the projection optical system 7 according to FIG. 9 substantially corresponds to the imaging beam path of the embodiment according to FIG. 8. A difference lies in the guidance of the imaging beam path section 28: this imaging beam path section 28 between the object field 4 and the mirror M1, in the embodiment according to FIG. 9, does not only intersect the imaging beam path section 24 between the mirrors M2 and M3, but also the imaging beam path section 25 between the mirrors M3 and M4 and the imaging beam path section 21 between the mirrors M4 and M5. An intersection region 31 of the intersection last mentioned between the imaging beam path section 28 and the imaging beam path section 21 in portions overlaps with the intersection regions 29 and 30. In the imaging beam path of the embodiment according to FIG. 9, the intersection regions 29 and 30 also overlap one another.

(75) An intersection region 32 of the intersection between the imaging beam path sections 28 and 25 is separated from the intersection regions 29 and 30 and partially overlaps with the intersection or crossing region 31.

(76) FIG. 10 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 9, have the same reference numerals and will not be described in detail again.

(77) An imaging beam path of the embodiment of the projection optical system 7 according to FIG. 10, apart from an arrangement mirrored about an xz-plane, is similar to the imaging beam path of the embodiment according to FIG. 2. In contrast to the imaging beam path according to FIG. 2, in the embodiment according to FIG. 10, the mirror M3 is located closer to the mirror M6 than the mirror M1. In the embodiment of the projection optical system 7 according to FIG. 2, the situation is precisely vice versa: there, the mirror M1 is closer to the mirror M6 than the mirror M3. In addition, in the embodiment of the projection optical system 7 according to FIG. 10, the mirror M2 is located significantly closer to the object plane 5 than the mirror M4.

(78) In the imaging beam path section 24 between the mirrors M2 and M3, in the embodiment according to FIG. 10, a diaphragm or stop 33 may be arranged in the region of a pupil plane of the projection optical system 7 according to FIG. 10. The imaging beam path section 24 is freely accessible from all sides in the region of this arrangement of the diaphragm 33.

(79) FIG. 11 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 10 have the same reference numerals and are not discussed again in detail.

(80) The imaging beam path in the embodiment of the projection optical system 7 according to FIG. 11 corresponds to the imaging beam path of the embodiment according to FIG. 8. In the projection optical systems according to FIGS. 11 to 14, mirrors M1 to M6 may be used that have different radii of curvature in two directions that are orthogonal to one another, in other words, on the one hand, in the xz-plane and, on the other hand, in the yz-plane.

(81) The projection optical system 7 according to FIG. 11 is telecentric on the object side.

(82) FIG. 12 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described with reference to the projection optical system 7 from FIGS. 2 to 11 have the same reference numerals and will not be discussed again in detail.

(83) The imaging beam path in the embodiment of the projection optical system 7 according to FIG. 12 is similar to that of the embodiment according to FIG. 2, apart from a view which is mirror-inverted about an xz-plane. In contrast to the embodiment according to FIG. 2, in the embodiment of the projection optical system 7 according to FIG. 12, in the imaging beam path section 27 between the mirrors M1 and M2, there is an intermediate image in an intermediate image plane 26 in addition to the further intermediate image in the intermediate image plane 19, which is located adjacent to the through-opening 18. In the embodiment of the projection optical system 7 according to FIG. 12, the mirror M3 is located closer to the mirror M6 than the mirror M1. This also distinguishes the imaging beam path of the projection optical system 7 according to FIG. 12 from that of the embodiment according to FIG. 2, where the mirror M1 is closer to the mirror M6 than the mirror M3.

(84) The projection optical system 7 according to FIG. 12 is telecentric on the object side.

(85) FIG. 13 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 12 have the same reference numerals and are not discussed again in detail.

(86) The imaging beam path, in the embodiment of the projection optical system 7 according to FIG. 12, is similar to the imaging beam path of the embodiment according to FIG. 8. In contrast to the embodiment according to FIG. 8, in the imaging beam path of the projection optical system 7 according to FIG. 13, in the imaging beam path section 25 between the mirrors M3 and M4, there is an intermediate image in an intermediate image plane 26, in addition to the intermediate image plane 19, which is located in the region of the through-opening 18.

(87) The projection optical system 7 according to FIG. 13 is telecentric on the object side.

(88) FIG. 14 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 13 have the same reference numerals and are not discussed again in detail.

(89) The imaging beam path in the embodiment of the projection optical system 7 according to FIG. 14 is similar to the imaging beam path of the embodiment according to FIG. 9. In contrast to the embodiment according to FIG. 9, an intermediate image is present in the imaging beam path of the projection optical system 7 according to FIG. 14, in the imaging beam path section 25 between the mirrors M3 and M4 and not between the mirrors M1 and M2, in an intermediate image plane 26 in addition to the intermediate image plane 19, which is located in the region of the through-opening 18.

(90) FIG. 15 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 14 have the same reference numerals and will not be discussed again in detail.

(91) The imaging beam path of the projection optical system 7 according to FIG. 15, between the mirror M2 and the image field 8, is similar to the imaging beam path of the embodiment according to FIG. 5.

(92) The imaging beam path section 27 between the mirrors M1 and M2, in the embodiment of the projection optical system 7 according to 15, is guided past both the mirror M6 and the mirror M4. Arranged adjacent to the mirror M4 in the imaging beam path section 27 is an intermediate image in an intermediate image plane 26 in addition to the intermediate image in the intermediate image plane 19, which is located close to the through-opening 18.

(93) FIG. 16 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 15 have the same reference numerals and will not be discussed again in detail.

(94) The imaging beam path of the projection optical system 7 according to FIG. 16 is similar to the imaging beam path according to FIG. 13. In contrast to the imaging beam path of the embodiment according to FIG. 13, in the projection optical system 7 according to FIG. 16, the imaging beam path section 24 between the mirrors M2 and M3 is guided past the mirror M6. In the embodiment according to FIG. 13, the mirrors M3 and M6 are arranged back to back.

(95) FIG. 17 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 16 have the same reference numerals and will not be discussed again in detail.

(96) The imaging beam path of the projection optical system 7 according to FIG. 17, from the mirror M3, is similar to the imaging beam path of the embodiment according to FIG. 13. In contrast to this, the imaging beam path section 28 between the object field 4 and the mirror M1 intersects the imaging beam path section 24 between the mirrors M2 and M3. A further difference between the embodiments according to FIGS. 17 and 3 is that in the embodiment according to FIG. 17 in the imaging beam path section 25 between the mirrors M3 and M4, an intermediate image is arranged in an intermediate image plane 26. This intermediate image is present in turn in addition to the intermediate image in the intermediate image plane 19 close to the through-opening 18.

(97) FIG. 18 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 17 have the same reference numerals and will not be discussed again in detail.

(98) The imaging beam path in the embodiment according to FIG. 18 between the object field 4 and the mirror M4 is guided in total on a side of the imaging beam path section 21 opposing the imaging light bundle 22 between the mirrors M4 and M5. The imaging beam path of the embodiment according to FIG. 18 differs in this regard from that of the embodiment of FIG. 2. The course of the imaging beam path between the object field 4 and the mirror M4 is otherwise reminiscent of the course of the imaging beam path in the projection optical system 7 according to FIG. 2. A further difference is that in the embodiment according to FIG. 18, a pupil plane 17 is arranged in the imaging beam path section 27 between the mirrors M1 and M2. Between these two mirrors, the imaging beam path section 27 is accessible in broad regions from all sides.

(99) The projection optical system 7 according to FIG. 18 has a numerical aperture NA on the image side of 0.33. The image field has an extent of 26 mm in the x-direction and of 2.5 mm in the y-direction. The image field 8 is rectangular.

(100) The projection optical system 7 according to FIG. 18 has a wave front error in the range between 0.03 and 0.10 (rms) over the image field 8.

(101) The mirrors M1 to M6 are designed as free-form faces of the tenth order.

(102) The mirror M6 has a diameter of 460 mm. The projection optical system 7 according to FIG. 18 has an overall length of 1630 mm between the object plane 5 and the image plane 9.

(103) The maximum angle of incidence on one of the mirrors M1 to M6 may be 17. The angle of incidence here is a maximum angle of incidence in the drawing plane of FIG. 18.

(104) The imaging beam path section 27 is guided past the mirror M6. The mirrors M3 and M6 are arranged back to back.

(105) FIG. 19 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 18 have the same reference numeral and will not be discussed again in detail.

(106) The imaging beam path in the embodiment of the projection optical system 7 according to FIG. 19 is similar to that of the embodiment according to FIG. 18.

(107) The projection optical system 7 according to FIG. 19 has a numerical aperture NA on the image side of 0.50. The image field has an extent of 26 mm in the x-direction and of 2.5 mm in the y-direction. The image field 8 is rectangular.

(108) The wave front error in the embodiment according to FIG. 19 is a maximum of 0.25 (rms) over the image field 8.

(109) The mirrors M1 to M6 are designed as free-form faces of the tenth order.

(110) The mirror M6 in the embodiment according to FIG. 19 has a diameter of 700 mm. The overall length of the projection optical system 7 according to FIG. 19 between the object plane 5 and the image plane 9 is 1800 mm.

(111) FIG. 20 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 19 have the same reference numerals and will not be discussed again in detail.

(112) The imaging beam path of the projection optical system 7 according to FIG. 20 corresponds to that of the embodiment according to FIG. 18.

(113) FIG. 21 shows a further embodiment of the projection optical system 7. Components which correspond to those which have already been described above with reference to the projection optical system 7 from FIGS. 2 to 20 have the same reference numerals and will not be discussed again in detail.

(114) The imaging beam path of the projection optical system 7 according to FIG. 21 corresponds to that of the embodiment according to FIG. 18.

(115) No back to back arrangements are present in the embodiments according to FIGS. 18 to 21 in the imaging beam path between the object field 4 and the mirror M4. In particular the mirrors M1 and M4 are not arranged back to back with respect to one another.

(116) To produce a microstructured or nanostructured component, the projection exposure installation 1 is used as follows: firstly, the reflection mask 10 or the reticle and the substrate or the wafer 11 are provided. A structure on the reticle 10 is then projected onto a light-sensitive layer of the wafer 11 with the aid of the projection exposure installation. By developing the light-sensitive layer, a microstructure or nanostructure is then produced on the wafer 11 and therefore the microstructured component.