Field facet mirror for an illumination optics unit for EUV projection lithography

Abstract

A field facet mirror for an illumination optics unit for EUV projection lithography is embodied for arrangement in the region of a field plane of the illumination optics unit. The field facet mirror has a plurality of field facets (25T) for the reflective transfer of illumination light (16) from a light source towards an object field with a predetermined distribution of an illumination light intensity over a field height of the object field. At least some of the field facets are embodied as partial field illumination facets (25T). These have a partial field illumination facet reflection portion (31) for the reflective transfer of the illumination light (16TF) as used illumination light from the light source towards a partial object field portion of the object field that is smaller than the object field. Furthermore, the respective partial field illumination facet (25T) has an output-coupling facet reflection portion (32) for the reflective transfer of the illumination light (16AK) as output-coupled illumination light from the light source towards at least one output-coupling component. Firstly the partial field illumination facet reflection portion (31) and secondly the output-coupling facet reflection portion (32) represent component parts of the respective partial field illumination facet (25T) that are fixed with respect to each other. This yields a field facet mirror, by means of which a challenging specification of an illumination intensity distribution over at least one object field coordinate is achieved without unwanted consequential effects.

Description

[0001] Field facet mirror for an illumination optics unit for EUV projection lithography

[0002] The present patent application claims the priority of German patent application DE 10 2024 211 125.2, the content of which is incorporated by reference herein.

[0003] The invention relates to a field facet mirror for an illumination optics unit for EUV projection lithography. The invention also relates to an optical assembly having such a field facet mirror, an illumination optics unit having such an optical assembly, an optical system having such an illumination optics unit and a projection exposure apparatus having such an optical system. The invention moreover relates to a method for producing a microstructured or nanostructured component using such a projection exposure apparatus and a microstructured or nano structured component produced using such a method.

[0004] A field facet mirror of the type set forth at the outset is known from WO 2011 / 154 244 Al and from WO 2009 / 132 756 Al. Further embodiments of an illumination optics unit for EUV projection lithography are known from WO 2023 / 208 557 Al. DE 10 2014 219 649 Al discloses an arrangement of an energy sensor module in a projection exposure apparatus. DE 10 2013 202 948 Al discloses an illumination system for an EUV lithography device and a facet mirror therefor. DE 10 2015 215 948 Al discloses an obscuration device for an optical system in a projection exposure apparatus. A problem addressed by the present invention is that of developing a field facet mirror of the type set forth at the outset, in such a way that a challenging specification of an illumination intensity distribution over at least one object field coordinate is achieved therewith without unwanted consequential effects.

[0005] According to the invention, this problem is solved by a field facet mirror having the features specified in Claim 1.

[0006] According to the invention, it was recognized that a reflective output coupling of illumination light by way of an output-coupling facet reflection portion of the respective partial field illumination facet on the one hand leads to the possibility of finely specifying an illumination intensity over an object field over at least one object field coordinate, as in principle already known from WO 2009 / 132 756 Al, and on the other hand also provides the possibility of avoiding disadvantages connected to absorbing partial field illumination facets.

[0007] The illumination light is guided over an illumination beam path by way of the partial field illumination facet reflection portion. The illumination light is guided over an output-coupling beam path, which deviates from the illumination beam path, by way of the output-coupling facet reflection portion.

[0008] The arrangement or embodiments of the reflection portions as fixed component parts of one and the same partial field illumination facet yields a precise and defined guidance of the output-coupled illumination light as well, and so the latter may be routed away in a targeted maimer and / or may be assigned to a further use, for example for monitoring purposes, possibly even over relatively long paths. A partial field illumination facet according to the invention may comprise multiple partial field illumination facet reflection portions and / or multiple output-coupling facet reflection portions, which all represent component parts of one and the same partial field illumination facet that are fixed with respect to one another.

[0009] As a result of firstly the partial field illumination facet reflection portion and secondly the output-coupling facet reflection portion of the respective partial field illumination facet each representing component parts of the respective partial field illumination facet that are fixed with respect to each other, there is a fixed angular relationship between firstly the partial field illumination facet reflection portion and secondly the output-coupling facet reflection portion of this partial field illumination facet.

[0010] The reflection portions of the respective partial field illumination facet may be one-piece component parts of one and the same monolithic partial illumination facet. Alternatively, the reflection portions may be fixed relative to each other on a joint carrier of the respective partial field illumination facet, for example screwed to each other on a carrier element of the respective partial field illumination facet.

[0011] Angles between the reflection portions according to Claim 4 were found to be particularly suitable for an effective separation of the illumination beam path from the output-coupling beam path. The angle between the partial field illumination facet reflection portion and the output-coupling facet reflection portion of a respective partial field illumination facet may lie in the range of between 100 mrad and 500 mrad and may for example lie in the range of between 200 mrad and 300 mrad. The angle between firstly the respective, at least one partial field illumination facet reflection portion and secondly the respective, at least one out- put-coupling facet reflection portion of the partial field illumination facet in question may give rise to a concave partial field illumination facet, or else a convex partial field illumination facet in an alternative. To the extent that multiple partial field illumination facet reflection portions and / or multiple output-coupling facet reflection portions form exactly one partial field illumination facet, this may also give rise to a partly concave and partly convex topography of the partial field illumination facet.

[0012] A tiltability of the at least one partial field illumination facet according to Claim 5 opens up advantages relating to field facets that are tiltable between different switching or tilt positions that were already explained in the prior art, for example in WO 2011 / 154 244 Al. A specification of different illumination settings, for example, is possible. On account of the fact that firstly the partial field illumination facet reflection portion and secondly the output-coupling facet reflection portion of the respective partial field illumination facet represent component parts of this partial field illumination facet that are fixed with respect to each other, a tilt of the respective partial field illumination facet leads to the simultaneous tilt of both the associated partial field illumination facet reflection portion and the output-coupling facet reflection portion through the same tilt angle.

[0013] The advantages of an optical assembly according to Claim 6 correspond to those which were already explained above in the context of the field facet mirror. A light trap according to Claim 7 enables reliable routing away of the illumination light via the output-coupling beam path. In an alternative to a light trap, the output-coupling component may also be used as a monitoring component for monitoring purposes, for example as a measurement structure for determining a layer degradation, or else as a monitoring sensor.

[0014] An embodiment of the light trap according to Claim 8 allows multiple out- put-coupling beam paths to be routed away via one and the same light trap. In the extreme case, exactly one light trap can be used for all output-coupling beam paths. A group-by-group assignment of certain groups of out- put-coupling beam paths to a specific light trap in each case is also possible.

[0015] A plurality of output-coupling components according to Claim 9 allows a flexible use of output-coupled illumination light. For example, separate light traps may be used for different output-coupling beam paths. As soon as a plurality of output-coupling components are provided, at least one out- put-coupling component may be designed as a light trap and a further one of the output-coupling components may be designed as a monitoring component.

[0016] An embodiment of an output-coupling component according to Claim 10 additionally reduces the number of output-coupling components required.

[0017] The advantages of an illumination optics unit according to Claim 11 correspond in principle to those which were already explained above in the context of the field facet mirror and the optical assembly. In addition to the relay facets that ensure a reflective transfer of the illumination light from the partial field illumination facet reflection portions, the illumination optics unit may also comprise further relay facets for optionally additional reflective transfer of the illumination light from further field facets, which are not embodied as partial field illumination facets, towards the object field. The relay facet mirror may be embodied as a pupil facet mirror with pupil facets arranged in the pupil plane of the illumination optics unit. The relay facet mirror may be embodied on the basis of a MEMS (microelectromechanical system) mirror. The relay facet mirror may be a component part of a specular reflector. Regarding the "specular reflector" aspect, reference is made to WO 2023 / 208 557 Al. The further mirror in the region of which the output-coupling component may be arranged in a variant of the illumination optics unit may be an illumination-light-guiding mirror between the relay facet mirror, i.e. the pupil facet mirror or the further mirror of the specular reflector for example, and the object field. In principle, such a further mirror may also be arranged between the field facet mirror and the relay facet mirror, i.e. the pupil facet mirror and a further mirror of the specular reflector for example.

[0018] The advantages of an illumination optical unit according to Claim 12 initially also correspond to those which were already explained above with reference to the field facet mirror and the optical assembly. In the region of the relay mirror, an embodiment of the output-coupling component may be embodied as monitoring unit, monitoring test structure and / or monitoring sensor in particular.

[0019] A combination of the illumination optics units according to Claims 11 and 12 is also possible.

[0020] The advantages of an optical system according to Claim 13, a projection exposure apparatus according to Claim 12, a production method according to Claim 15 and a microstructured or nanostructured component according to Claim 16 correspond to those which have already been explained above with reference to the specification method according to the invention.

[0021] The component can be produced with an extremely high structural resolution. In this way, it is possible for example to produce a semiconductor chip having an extremely high integration or storage density.

[0022] Exemplary embodiments of the invention are explained in more detail below with reference to the drawing, in which:

[0023] Fig. 1 schematically shows a meridional section through a projection exposure apparatus for EUV projection lithography;

[0024] Fig. 2 schematically shows a plan view of a far field of the source optics unit - an illumination intensity - in the region of an arrangement plane of a field facet mirror of an illumination optics unit in the projection exposure apparatus, with three field facets of the field facet mirror being highlighted by way of example;

[0025] Fig. 3 shows a perspective view of an arrangement of field facets, including field facet carriers, of an embodiment of the field facet mirror, with two of the field facets being embodied as partial field illumination facets by way of example;

[0026] Fig. 4 schematically shows a beam path for guiding a chief ray of a central field point from an intermediate focal plane to an object field, this being an alternative guide to the light guidance according to Fig. 1, wherein beam paths of the chief ray are illustrated firstly in a maimer reflected off a partial field illumination facet reflection portion of a field facet embodied as a partial field illumination facet and secondly in a manner reflected off an output-coupling facet reflection portion of the same partial field illumination facet, wherein illumination light is guided from the output-coupling facet reflection portion towards an output-coupling component in the form of a light trap, which is embodied as a joint light trap for multiple tilt positions of the partial field illumination facet;

[0027] Fig. 5 shows an enlarged detail from Fig. 4 in the region of a reflection of the illumination light off the partial field illumination facet;

[0028] Fig. 6 again shows in an illustration similar to Fig. 4 how light is guided from the intermediate focus to the object field, wherein a further embodiment of an output-coupling component in the form of multiple individual light traps is shown, to which the illumination light is guided in a respective tilt position of the partial field illumination facet reflection portion and hence of the partial field illumination facet; and

[0029] Fig. 7 again shows in an illustration similar to Fig. 4 how the illumination light is guided from the intermediate focus towards the object field, wherein an alternative embodiment of an outputcoupling component in place of a light trap is illustrated, to which the illumination light is guided via respective partial field illumination facet reflection portions and assigned facets of a second facet mirror (pupil facet mirror) of an illumination optics unit of the projection exposure apparatus, wherein this variant of the output-coupling component is embodied as a plurality of monitoring units that are arranged in the region of a mirror of the illumination optics unit in the projection exposure apparatus disposed downstream of the second facet mirror.

[0030] Fig. 1 schematically shows a microlithographic projection exposure apparatus 1 in a meridional section. The projection exposure apparatus 1 includes a light or radiation source 2. An illumination system 3 of the projection exposure apparatus 1 has an illumination optics unit 4 for exposing an illumination field coinciding with an object field 5 in an object plane 6. The illumination field may also be larger than the object field 5. In this case, an object in the form of a reticle 7 that is arranged in the object field 5 and held by an object or reticle holder 8 is exposed. The reticle 7 is also referred to as lithography mask. The object holder 8 is displaceable in an object displacement direction by means of an object displacement drive 9. A projection optics unit 10 serves for imaging the object field 5 into an image field 11 in an image plane 12. A structure on the reticle 7 is imaged onto a light-sensitive layer of a wafer 13 that is arranged in the region of the image field 11 in the image plane 12. The wafer 13 is held by a wafer holder 14. By way of a wafer displacement drive 15, the wafer holder 14 is displaceable parallel to the object displacement direction in a maimer synchronized with the object holder 8.

[0031] The radiation source 2 is an EUV radiation source with emitted used radiation in the range of between 5 nm and 30 nm. This may be a plasma source, for example a GDPP (gas discharge-produced plasma) source or an LPP (laser-produced plasma) source. A radiation source based on a synchrotion or on a free election laser (FEL) may also be used for the radiation source 2. A person skilled in the art finds information about such a radiation source in US 6,859,515 B2, for example. EUV radiation 16 that emanates from the radiation source 2, in particular the used illumination light that illuminates the object field 5, is focused by a collector 17. A corresponding collector is known from EP 1 225 481 A. Downstream of the collector 17, the EUV radiation 16 propagates through an intermediate focus IF in the region of an intermediate focal plane 18 before the EUV radiation 169 is incident on a field facet mirror 19. The field facet mirror 19 is a first facet mirror of the illumination optics unit 4. The field facet mirror 19 has a plurality of reflective field facets, which are not depicted in Fig. 1. The field facet mirror 19 is arranged in a field plane of the illumination optics unit 4, from where imaging into the object plane 6 takes place.

[0032] The EUV radiation 16 is also referred to hereinafter as used light, illumination light or as imaging light.

[0033] Downstream of the field facet mirror 19, the EUV radiation 16 is reflected off a pupil facet mirror 20. The pupil facet mirror 20 is a second facet mirror of the illumination optics unit 4. The pupil facet mirror 20 is arranged in a pupil plane of the illumination optics unit 4. The pupil facet mirror 20 has a plurality of reflective pupil facets. The field facets of the field facet mirror 19 are imaged into the object field 5 overlaid on one another with the aid of the pupil facets of the pupil facet mirror 20 and an imaging optical assembly downstream thereof in the form of a transfer optics unit 21 having mirrors 22, 23 and 24, denoted by the order in the beam path. The last mirror 24 of the transfer optics 21 is a grazing incidence mirror. Depending on the embodiment of the illumination optics unit 4, the transfer optics unit 21 may also comprise fewer than three mirrors, for example exactly one mirror. This mirror or at least one of the mirrors of the transfer optics unit 21 may be embodied as a correction mirror for correcting illumination properties of the illumination optics unit 4. In certain embodiments of the illumination optics unit 4, the transfer optics unit 21 may also be omitted entirely such that the second facet mirror 20 represents the last optical component guiding the illumination light 16 upstream of the object field 5. In that case, the pupil facet mirror 20 is the only component of the transfer optics unit 21.

[0034] In order to facilitate the description of positional relationships, Fig. 1 plots a Cartesian xyz-coordinate system as a global coordinate system for the description of the positional relationships of components of the projection exposure apparatus 1 between the object plane 6 and the image plane 12. In Fig. 1, the x-axis extends perpendicularly to the plane of the drawing into the latter. In Fig. 1, the y-axis extends to the right and parallel to the displacement direction of the object holder 8 and of the wafer holder 14. In Fig. 1, the z-axis extends downwards, i.e. perpendicular to the object plane 6 and to the image plane 12.

[0035] The x-dimension over the object field 5 or the image field 11 is also referred to as the field height. The object displacement direction extends parallel to the y-axis.

[0036] Local Cartesian xyz-coordinate systems are plotted in the further figures. The x-axes of the local coordinate systems extend parallel to the x-axis of the global coordinate system according to Fig. 1. The xy-planes of the local coordinate systems represent arrangement planes of the components in each case presented in the figure. The y- and z-axes of the local coordinate systems are accordingly tilted through a certain angle about the respective x-axis.

[0037] Examples of various facet arrangements for the field facet mirror 19 and the pupil facet mirror 20 are known from WO 2016 / 128 253 Al, WO 2009 / 100 856 Al, US 6,438,199 Bl and

[0038] US 6,658,084 B2.

[0039] The field facet mirror 19 has a multiplicity of field facets 25 with an arcuate design. These are arranged, in groups, in field facet blocks on a field facet carrier. Overall, the field facet mirror 19 has a plurality of field facet blocks, in which three, five or ten of the field facets 25 are combined in groups.

[0040] In an alternative, the field facet mirror 19 may also comprise rectangular field facets 25, which again are arranged, in groups, in field facet blocks.

[0041] At least some of the field facets 25 are embodied as partial field illumination facets; this will still be explained below, especially in the context of Fig. 3 et seq.

[0042] Pupil facets 29 of the pupil facet mirror 20 are arranged in the region of an illumination pupil of the illumination optics unit 4. The pupil facets 29 are arranged on a pupil facet carrier of the pupil facet mirror 20. A spatial distribution of pupil facets 29, on which the illumination light 16 is incident via the field facets 25, within the illumination pupil specifies an actual illumination angle distribution in the object field 5. Each of the field facets 25 serves to transfer some of the illumination light 16, i.e. an illumination light component beam 16i, from the light source 2 towards one of the pupil facets 29.

[0043] The field facets 25 in each case are first facets of the illumination optics unit 4 in the beam path of the illumination light 16. Accordingly, the pupil facets 29 are second facets of the illumination optics unit 4 in the beam path of the illumination light 16.

[0044] For each of the illumination channels 16i, the transfer optics unit 21 in each case comprises one of the pupil facets 29 for transferring the illumination light component beam 16i from the respective field facet 25 towards the object field 5.

[0045] In each case one illumination light component beam 16i, of which two illumination light component beams 16i (i = 1,..., N; N: number or the field facets) are shown schematically in Fig. 1, is guided between the light source 2 and the object field 5 over exactly one of the field facets 25 and over exactly one of the pupil facets 29, in each case via an illumination channel.

[0046] Fig. 2 schematically shows a far field illumination intensity distribution, illustrated by way of isolines li of equal intensity, in an arrangement plane of the field facet mirror 19. In Fig. 2, three field facets 25A, 25B and 25c of the field facet mirror 19 are depicted by way of example. Moreover, in the field facet mirror arrangement plane according to Fig. 2, the far field is shadowed in the region of a centre Z. The isolines li extend rotationally symmetrically about the centre Z, ideally on concentric circular lines.

[0047] In the far field according to Fig. 2, the highest illumination intensity (isoline li) is located in the vicinity of the centre shadow Z. With increasing distance from the centre Z, the illumination intensity reduces continually to an intensity value h located radially on the outside. The illumination intensities used by impingement upon the field facets 25i may differ by more than 50% and may for example differ by a factor of 2, by a factor of 3, by a factor of 4, by a factor of 5 or by a still greater factor.

[0048] Fig. 3 illustrates a spatial arrangement of the field facets 25 of the field facet mirror 19 in a perspective illustration. The field facets 25 are carried by respective carrier elements 30. In principle, the field facet arrangement according to Fig. 3 is known from WO 2009 / 132 756 Al.

[0049] At least some of the field facets 25 are embodied as partial field illumination facets 25T. By way of example, such a partial field illumination facet 25T is illustrated, inter alia, right at the top in the facet column depicted far left in the facet arrangement according to Fig. 3. Since the partial field illumination facets 25T all have a similar construction, a description on the basis of one of these partial field illumination facets is sufficient.

[0050] An illumination intensity distribution over an x-object field coordinate can be influenced by way of the partial field illumination facets 25T. In particular, there may be an illumination intensity distribution over an x-field height a specification of an illumination intensity distribution over the x- field height. For example, a targeted illumination intensity homogeneity over the x-field height may be attained by selecting appropriate partial field illumination facets. This x-field height specification of an illumination intensity distribution may be effected in accordance with what is known from WO 2009 / 132 756 Al, for example.

[0051] The partial field illumination facet 25 has a partial field illumination facet reflection portion 31 for the reflective transfer of the illumination light 16 as used light from the light source 2 towards a partial object field portion 5T (cf. also Fig. 1) that is smaller than the entire object field 5. Furthermore, the partial field illumination facet 25 has an output-coupling facet reflection portion 32 for the reflective transfer of the illumination light 16 as output-coupled illumination light from the light source 2 towards at least one output-coupling component, as will be explained below.

[0052] Firstly the partial field illumination facet reflection portion 31 and secondly the output-coupling facet reflection portion 32 are component parts of the partial field illumination facet 25 that are fixed with respect to each other. In the embodiment according to Fig. 3, the two reflection portions 31, 32 are one-piece, monolithic component parts of one and the same partial field illumination facet 25T. Alternatively, it is possible to fix these two reflection portions 31, 32 with respect to each other and for example screw these, fixed to each other, onto the joint carrier element 30.

[0053] Each of the field facets 25 or 25 is embodied to be tiltable by way of an associated actuator system 26; in principle, this is already known from the prior art. In Fig. 3, such an actuator system 26 is indicated for exactly one field facet 25 with an associated carrier element 30. The field facet mirror 19 may comprise exactly one partial field illumination facet 25T. Alternatively, the field facet mirror 19 may comprise multiple partial field illumination facets 25T. For example, 1% to 20% of the field facets 25 may be embodied as partial field illumination facets 25 with the corresponding reflection surface portions 31, 32. In principle, the proportion of partial field illumination facets 25 relative to the total number of field facets 25 may also be greater than 20%. In individual cases, the majority of the field facets 25 may also be embodied as partial field illumination facets 25T, and for example all field facets 25 may be embodied as partial field illumination facets 25T.

[0054] Fig. 4 schematically shows a beam path of rays 16TF, 16AK of the illumination light 16 between the intermediate focus IF and the object field 5. Components and functions that correspond to those which have already been explained above with reference to Figs 1 to 3, and in particular with reference to Fig. 3, bear the same reference signs and will not be discussed in detail again.

[0055] An embodiment of the transfer optics unit 21 is shown schematically with exactly one further mirror 22 in the illumination beam path of the illumination light 16 downstream of the pupil facet mirror 20. Only one light channel is elucidated in Fig. 4; it is guided over exactly one field facet 25 and over exactly one pupil facet 29.

[0056] Fig. 5 shows an enlarged detail from Fig. 4 in the region where the two rays 16TF, 16AK are reflected off a field facet 25, embodied once again as a partial field illumination facet 25T, of the field facet mirror 19. An output- coupling beam path of the output-coupled ray 16AK deviates from an illumination beam path of the partial field illumination ray 16TF following the reflection off the partial field illumination facet 25T.

[0057] The partial field illumination ray 16TF is guided via the partial field illumination facet reflection portion 31 towards an associated pupil facet 29 of the pupil facet mirror 20 and, from there, guided via the further mirror 22 of the transfer optics unit 21 towards the object field 5.

[0058] The output-coupling facet reflection portion 32 is tilted through a tilt angle a relative to an arrangement plane 33 of a reflection surface of the partial field illumination facet reflection portion 31. Depending on the embodiment of the partial field illumination facet 25T, the tilt angle a may lie in the range of between 50 mrad and 1000 mrad and in particular in the range of between 100 mrad and 500 mrad, for example in the range of between 200 mrad and 300 mrad. This tilt angle may be the same as illustrated in Fig. 5, in which the output-coupling facet reflection surface portion 32 is raised in comparison with the partial field illumination facet reflection portion 31, or else such that the output-coupling facet reflection portion 32 is for example manufactured by removing material from a main body 34 of the partial field illumination facet 25T, i.e. realized in the form of a wedge- shaped cutout that is lowered down in comparison with the partial field illumination facet reflection portion 31.

[0059] There is an edge region 35 (cf. also Fig. 3), which may be a concave edge like in the embodiment according to Fig. 5 or else a convex edge, between the two reflection portions 31, 32. This edge region 35 extends along the y- axis, i.e. perpendicular to an x-field height of the partial field illumination facet 25T that is imaged into the x-object field coordinate. An x-position of the edge region 35 on the partial field illumination facet 25T may vary among different partial field illumination facets 25T. A ratio of the area between the partial field illumination facet reflection portion 31 and the output-coupling facet reflection portion 32 of the respective partial field illumination facet 25 may lie in the range of between 10: 1 and 1: 10, in particular in the range of between 5: 1 and 1:5, for example between 3: 1 and 1:3, depending on the embodiment of this partial field illumination facet 25T. A division in half between the reflection portions 31, 32 by way of the edge region 35 is also possible.

[0060] The output-coupled ray 16AK is guided by the output-coupling facet reflection portion 32 towards an output-coupling component 36, which is a light trap in the embodiment according to Figs 4 and 5.

[0061] The light trap 36 is arranged in the region of the second facet mirror 20.

[0062] Transverse to the output-coupling beam path of the ray 16AK, the light trap 36 has a trap area 37 that is more than twice the size of an area of incidence 38i of an illumination beam path channel that is guided via exactly one out- put-coupling facet reflection portion 32. In Fig. 4, the area of incidence 38i for the depicted output-coupled ray 16AK is depicted as a surface portion of the trap area 37 of the light trap 36.

[0063] A further area of incidence of a further illumination beam path channel, by means of which the output-coupled ray 16AK is guided via the output-coupling facet reflection portion 32 in a second tilt position of the partial field illumination facet 25 depicted in Figs 4 and 5, is depicted at 382, once again as a surface portion of the entire trap area 37 of the light trap 36. The extent of the trap area 37 transverse to the output-coupling beam path 16AK is more than twice the extent of the respective area of incidence 38i. Thus, in the embodiment according to Fig. 4, the light trap 36 is so large that the output-coupled illumination light 16AK is guided onto this light trap 36 independently of the respective tilt position of the output-coupling facet reflection portion 32 of the partial field illumination facet 25T.

[0064] The light trap 36 may be embodied as a component that absorbs the output- coupled illumination light 16AK. The light trap 36 may be embodied with active or passive cooling. This may be implemented with the aid of a cooling module, for example with Peltier cooling or else with the aid of a coolant guided in a circuit in particular. In an alternative to that or in addition, the cooling module may comprise an enlarged surface for heat emission, in particular cooling ribs.

[0065] The light trap 36 may also be embodied in such a way that output-coupled illumination light 16AK, which is guided via output-coupling facet reflection portions 32 of different partial field illumination facets 31, is incident on one and the same light trap 36, i.e. onto the trap area 37 there.

[0066] The second facet mirror 20 is also referred to as relay facet mirror. The second facets 29 are also referred to as relay facets for the reflective transfer of the used light 16 from the partial field illumination facet reflection portions 31 towards the respective partial object field portion.

[0067] Fig. 6 shows a further embodiment of a light guide, which is comparable to that according to Fig. 4. In contrast to the embodiment according to Fig. 4, an output-coupling component 39 in the style of the output-coupling component 36 is embodied as an output-coupling component with multiple trap surfaces 37i, 372 that are separated from one another in the embodiment according to Fig. 6. The trap area 37i serves as area of incidence for the out- put-coupling beam path 16AK in the switching position of the partial field illumination facet 25 that is reproduced in Fig. 6 and that represents a first tilt position of the partial field illumination facet 25T. The further trap area 372 of the output-coupling component, i.e. of the light trap 39, serves as area of incidence for the output-coupled ray 16AK in a second tilt position of this partial field illumination facet 25T.

[0068] Depending on the embodiment, the light trap 39 may comprise more than two trap areas 37i, for example three, four, five, eight, ten, fifteen, twenty, thirty, fifty or even more trap areas 37i, wherein each of these trap areas 37i may be embodied to guide exactly one output-coupled illumination beam, which is guided via an output-coupling facet reflection portion 32 of a specific partial illumination facet 25T.

[0069] A further embodiment of an output-coupling component 40 is described hereinafter on the basis of Fig. 7; said output-coupling component can be used as an alternative or in addition to the variants of the output-coupling components 36 according to Fig. 4 and 39 according to Fig. 6. An illustration of a beam path in Fig. 7 between the intermediate focus IF and the object field 5 corresponds in principle to that according to Figs 4 and 6. Components and functions which were already explained above with reference to Figs 1 to 6, in particular with reference to Figs 4 to 6, are denoted by the same reference signs and are not discussed in detail again.

[0070] In the embodiment according to Fig. 7, the output-coupling component 40 is embodied as a plurality of monitoring units 4 li, wherein exactly two monitoring units 4h and 4h are illustrated in Fig. 7. These monitoring units 4 li are arranged in the region of the relay mirror 22, i.e. adjacent to but separate from the latter.

[0071] What is shown is an output-coupling beam path from a reflection off the output-coupling facet reflection portion 32 of the partial field illumination facet 25T illustrated in Fig. 7, for two switching positions of this partial field illumination facet 25T. Accordingly, Fig. 7 illustrates an output-coupled ray 25AKI for a first switching position for the partial field illumination facet 25T and an output-coupled ray 25AK2 for a second switching position of this partial field illumination facet 25T.

[0072] The output-coupled ray 25AKI is guided towards the monitoring unit 4h and the output-coupled ray 25AK2 is guided towards the monitoring unit 4h.

[0073] The monitoring units 4 li serve to monitor an impingement intensity or a layer degradation in the region of the relay mirror 22. The monitoring units 4 li might be monitoring samples that are coated in the same way as the relay mirror 23, or intensity or energy sensors for monitoring a corresponding intensity or energy present in the respective output-coupled ray 4 li. Hence, the output-coupling component 40 enables monitoring of a layer degradation and / or monitoring of a layer performance of the facet mirror 19, 20, or else a performance of the light source 2 or of the collector 17.

[0074] During the projection exposure with the aid of the projection exposure apparatus 1, a specified x-illumination intensity distribution over the object field 5 is initially set with the aid of the setting method explained above. Then, at least one part of the reticle 7 in the object field 5 is imaged onto a region of the light-sensitive layer onto the wafer 13 in the image field 11 for the lithographic production of a microstructured or nanostructured component, in particular of a semiconductor component, for example of a microchip. In this case, the reticle 7 and the wafer 13 are moved in a temporally synchronized maimer in the y-direction continuously in scanner oper- ation.

Claims

Claims1. Field facet mirror (19) for an illumination optics unit (4) for EUV projection lithography, embodied for arrangement in the region of a field plane of the illumination optics unit (4), having a plurality of field facets (25, 25 ) for the reflective transfer of illumination light (16) from a light source (2) towards an object field (5) with a predetermined distribution of an illumination light intensity over a field height (x) of the object field (5), wherein at least some of the field facets are embodied as partial field illumination facets (25 ) and comprise:— a partial field illumination facet reflection portion (31) for the reflective transfer of the illumination light (16TF) as used illumination light from the light source (2) towards a partial object field portion of the object field (5) that is smaller than the object field (5),— an output-coupling facet reflection portion (32) for the reflective transfer of the illumination light (16AK) as output-coupled illumination light from the light source (2) towards at least one output-coupling component (36; 39; 40), wherein firstly the partial field illumination facet reflection portion (31) and secondly the output-coupling facet reflection portion (32) represent component parts of the respective partial field illumination facet (25T) that are fixed with respect to each other.

2. Field facet mirror according to Claim 1, characterized in that firstly the partial field illumination facet reflection portion (31) and secondlythe output-coupling facet reflection portion (32) of the respective partial field illumination facet (25 ) are one-piece component parts of this partial field illumination facet (25T).

3. Field facet mirror according to Claim 2, characterized in that the respective partial field illumination facet (25T) has a monolithic embodiment.

4. Field facet mirror according to any of Claims 1 to 3, characterized by an angle (a) between the partial field illumination facet reflection portion (31) and the output-coupling facet reflection portion (32) in the range of between 50 mrad and 1000 mrad.

5. Field facet mirror according to any of Claims 1 to 4, characterized in that the partial field illumination facets (25 ) are embodied by way of an actuator system (26) to be tiltable between different tilt positions for the reflective transfer of the illumination light (16) in different directions.

6. Optical assembly having a facet mirror (19) according to any of Claims 1 to 5 and having the output-coupling component (36; 39; 40).

7. Optical assembly according to Claim 6, characterized in that the out- put-coupling component (36; 39) is embodied as a light trap.

8. Optical assembly according to Claim 7, characterized in that transverse to an output-coupling beam path (16AK) the light trap has a trap area (37) that is more than twice the size of an area of incidence (380of an illumination light beam path channel that is guided via exactly one output-coupling facet reflection portion (31).

9. Optical assembly according to any of Claims 6 to 8, characterized by a plurality of output-coupling components (370.

10. Optical assembly according to any of Claims 6 to 9, characterized in that one and the same output-coupling component (36) is embodied for the impingement of illumination light (16) that is guided via outputcoupling facet reflection portions (32) of different partial field illumination facets (25T.

11. Illumination optics unit having an optical assembly according to any of Claims 6 to 10, having a relay facet mirror (20) with a plurality of relay facets (29) for the reflective transfer of the illumination light (16) from the partial field illumination facet reflection portions (31) towards the partial object field portion, wherein the output-coupling component (36; 39) is arranged in the region of the relay facet mirror (20) or in the region of a further mirror (22, 23, 24) that follows the field facet mirror (19).

12. Illumination optics unit having an optical assembly according to any of Claims 6 to 10, having a relay mirror (22) downstream of the field facet mirror (19) in the beam path of the illumination light (16) and serving the reflective transfer of the illumination light (16) from the partial field illumination facet reflection portions (31) towards the partial object field portion,wherein the output-coupling component (40) is arranged in the region of the relay mirror (22).

13. Optical system having an illumination optics unit (4) according to Claim 11 or 12 and having a projection optics unit (10) for imaging the object field (5) into an image field (11).

14. Projection exposure apparatus (1) having an optical system according to Claim 13 and a light source (2) for generating the illumination light (16), having an object holder (8) with an object displacement drive (9) for displacing the object (7) in an object displacement direction (y), having a wafer holder (14) with a wafer displacement drive (15) for displacing a wafer (13) in a maimer synchronized with the object displacement drive (9).

15. Method for producing a microstructured and / or nanostructured component, including the following steps: providing a projection exposure apparatus (1) according to Claim14, providing a wafer (13), providing a lithography mask (7), projecting at least a part of the lithography mask (7) onto a region of a light-sensitive layer of the wafer (13) with the aid of the projection optics unit (10) of the projection exposure apparatus (1).

16. Component, produced by a method according to Claim 15.

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