TW201626111A - Illumination optical unit for illuminating an illumination field and projection exposure apparatus comprising such an illumination optical unit - Google Patents

Abstract

An illumination optical unit serves to illuminate an illumination field in which an object to be imaged is arrangeable. The illumination optical unit comprises at least one facet mirror and one deflection mirror assembly (5b) in the beam path of an illumination light beam (22) upstream of the facet mirror. The deflection mirror assembly (5b) is embodied in such a way that it deflects a centroid ray (Sin, Sout) of the illumination light beam (22) by at least 10 DEG. The deflection mirror assembly (5b) has at least two mirrors (23, 24) for grazing incidence. These each reflect a dedicated partial beam (25, 26) of the overall illumination light beam (22). What emerges is an illumination optical unit which can be adapted to various light source configurations with little outlay.

Description

Illumination optical unit for illuminating an illumination field and projection exposure apparatus comprising such illumination optical unit [Related patent reference]

The priority of the German patent application DE 10 2014 223 454.9 is incorporated herein by reference.

The invention relates to an illumination optical unit for illuminating an illumination field, an object to be imaged being configurable therein. Furthermore, the present invention relates to an illumination system including such an illumination optical unit, an optical system including the illumination optical unit and an imaging optical unit for imaging an illumination field in an image field, a projection exposure apparatus including the optical system, A method for producing a microstructure or nanostructure component and a component produced by the method.

An illumination optical unit as an assembly of a projection exposure apparatus is disclosed in US 2005/0207039 A1, US 2003/0095623 A1, US 2005/0093041 A1, US 2005/0094764 A1, and US 2005/0274897 A1.

It is an object of the present invention to develop an illumination optical unit that is adaptable to a variety of light source configurations and that is inexpensive.

According to the invention, this object is achieved by an illumination optical unit comprising the features set forth in claim 1 of the scope of the patent application.

Due to its deflecting effect on the centroid ray, the deflecting mirror assembly is capable of accommodating light sources having different centroid ray distributions of the illumination beam emitted by the light source. The deflecting mirror assembly can receive an emitted illumination beam having a centroid ray distribution predefined by the configuration of the light source and deflect it into a subsequent illumination optical unit having at least one facet mirror Reflected centroid ray distribution. The centroid ray deflection by the deflecting mirror assembly can be at least 15° or at least 20°. A deflection angle of, for example, 19°, 20° or 25° is also possible. By designing the reflective surface of the mirror for grazing incidence of the deflecting mirror assembly, it is also possible to change more illumination parameters depending on the individual light source configuration, so that these match the subsequent illumination optical unit . In particular, the deflecting mirror assembly can be used to adjust the light spread of the light source to an acceptable light spread of the subsequent illumination optical unit. The deflecting mirror assembly can be implemented to have high reflection efficiency. Mirrors for tangential incidence can be implemented as curved mirrors, especially concave curved mirrors. The reflective surface of the mirror for tangential incidence can be implemented as an aspherical surface. The reflective surface of the mirror for tangential incidence can be implemented as a freeform surface that cannot be described by a rotationally symmetric surface. The deflecting mirror assembly can be disposed downstream of one of the collectors of the illumination light collecting the light source.

The configuration as described in claim 2 will enable a particularly advantageous embodiment of the deflecting mirror assembly. The deflecting mirror assembly can be configured to be a small distance from the intermediate focus. For example, the distance between the intermediate focus and the deflecting mirror assembly can be less than one-third or one-fifth of the optical path between the intermediate focus and the next facet mirror of the illumination optics unit.

The specific embodiment described in claim 3 of the patent application enables the use of a deflecting mirror assembly having a light source providing a corresponding maximum numerical aperture of 0.3 at an intermediate focus. Deflection The mirror assembly can be implemented to cover a numerical aperture of, for example, an intermediate focus of 0.22.

The effect of the deflection mirror assembly variation (e.g., increased or decreased as described in claim 4), the effective numerical aperture of the intermediate focus enables the use of, for example, a light source having a relatively small numerical aperture (which is unbiased) The mirror assembly is provided in the intermediate focus region in combination with an illumination optical unit disposed downstream thereof, in contrast to which the illumination optical unit can process the numerical aperture of the relatively large intermediate focus. Next, it is possible to use an illumination optical unit designed for a type of light source having a numerical aperture of relatively high intermediate focus, wherein the illumination optical unit can also provide a relatively low intermediate focus by using a deflecting mirror assembly. A numerical aperture source is used together. The increased effective numerical aperture available after reflection of the deflecting mirror assembly can be, for example, 0.2 or 0.22. This also applies to the opposite case where the illumination system (which is expected to have a relatively small numerical aperture (e.g., 0.16)) can therefore operate using a light source that provides a relatively large numerical aperture (e.g., 0.22). Here is a specific application. The divergence of the partial illumination light beam corresponds to an effective numerical aperture after reflection of the deflecting mirror assembly, which is increased by at least 10% compared to a numerical aperture of the intermediate focus. Basically, the effective numerical aperture of the partial illumination light beam can also be as large as the numerical aperture of the intermediate focus. This can be achieved by implementing the mirror of the deflecting mirror assembly as a planar mirror.

More than two mirrors for tangential incidence, as described in claim 5, enable specific adjustment of the parameters of the sub-beams reflected by these mirrors. In particular, a specific adjustment of the far field geometry consisting of the far field of the partial beam is possible. The deflecting mirror assembly can have three mirrors, four mirrors, five mirrors, six mirrors, eight mirrors, ten mirrors, or more.

The specific embodiment described in claim 6 of the patent application enables a relatively simple design of a tangentially incident mirror. In this way it is possible to use a relatively large number of mirrors to mirror the far field intensity distribution, the far field downstream of the deflecting mirror assembly is less than using a smaller number of mirrors. The case of mapping the far field intensity distribution is more similar to the original, unmapped far field. Optimized in the original far field intensity distribution A relatively small switching angle of at least one of the facets of the facet mirror is required, which can be maintained even after reflection of the deflecting mirror assembly.

A hyperboloid mirror as described in claim 7 (i.e., a mirror whose reflective surface is implemented as a section of a hyperboloid) will result in a beam of the deflecting mirror assembly in the reflected portion of the beam. There is a corresponding effect on the parameters. This hyperboloid embodiment is suitable for increasing and decreasing the effective numerical aperture.

The spaced configuration of the mirror for tangential incidence as described in claim 8 will increase the mounting space available for the adjacent mirrors of the deflecting mirror assembly.

The illumination system of claim 9 and claim 10, wherein the optical system of claim 11 is the projection exposure apparatus of claim 12, as claimed in claim 13 The production method described in the item and the advantages of the microstructure or nanostructure assembly as described in claim 14 correspond to the advantages already explained in the foregoing with reference to the illumination optical unit according to the invention. An EUV source can be used as an illumination source. In particular, the components produced are semiconductor wafers, such as memory chips.

1‧‧‧Projection exposure device

2‧‧‧Light source

3‧‧‧Lights

4‧‧‧Transmission optical unit

5‧‧‧ concentrator

5a‧‧‧Intermediate focus

5b‧‧‧ deflecting mirror assembly

6‧‧‧Transmission kneading mirror

6a‧‧‧Edge contour

7‧‧‧Lighting preset facet mirror

8‧‧‧Lighting optical unit

9‧‧‧Photomask

10‧‧‧ object plane

11‧‧‧Projection optical unit

12‧‧‧物场

12a‧‧‧Photomask Holder

12b‧‧‧Object displacement drive

13‧‧‧object side numerical aperture

14‧‧‧Image field side numerical aperture

15‧‧‧Optical components

16‧‧‧Optical components

17‧‧‧Image field

18‧‧‧ image plane

19‧‧‧ Wafer

20‧‧‧Retainer

21‧‧‧ Wafer Displacement Driver

22‧‧‧ illumination beam

23‧‧‧GI mirror

24‧‧‧GI mirror

25‧‧‧Partial beam

26‧‧‧Partial beam

27‧‧‧Outer edge ray

28‧‧‧ Far field

29‧‧‧Mirror plane

30‧‧‧Mirror plane

31‧‧‧Outer edge contour

32‧‧‧Half ring

33‧‧‧ half ring

34‧‧‧ deflecting mirror assembly

35‧‧‧Installation space

36‧‧‧Installation space

37‧‧‧ deflecting mirror assembly

38‧‧‧ deflecting mirror assembly

39‧‧‧GI mirror

40‧‧‧GI mirror

41‧‧‧GI mirror

42‧‧‧GI mirror

43‧‧‧Partial beam

44‧‧‧Partial beam

45‧‧‧Partial beam

46‧‧‧Partial beam

47‧‧‧ Far field

48‧‧‧Mirror plane

49‧‧‧Mirror plane

50‧‧‧Mirror plane

51‧‧‧Mirror plane

52‧‧‧ part of the ring

53‧‧‧ part of the ring

54‧‧‧Partial ring section

55‧‧‧ part of the ring

56‧‧‧ arrow

‧‧‧‧ deflection angle

S _in ‧‧‧centroid ray

S _out ‧‧‧centroid ray

Z‧‧‧ Ring Center

Exemplary embodiments of the present invention will be explained in more detail below based on the drawings. 1 shows a very simplified longitudinal section of a projection exposure apparatus for EUV lithography, comprising a light source, an illumination optical unit and a projection optical unit; FIG. 2 shows a partial enlarged view of the area II of FIG. a deflecting mirror assembly of the illumination optics unit in the beam path of the illumination beam downstream of the intermediate focus; FIG. 3 shows another embodiment of the deflecting mirror assembly that marks the spatial requirements of the various illumination-optical components; 4 shows another configuration example of a deflecting mirror similar to the deflecting mirror assembly of FIG. 3, which may be used in place of the deflecting mirror assembly of FIGS. 2 and 3; Figure 5 shows another embodiment of a deflecting mirror assembly having four deflecting mirrors similar to Figure 2; Figure 6 is shown schematically in the optical path downstream of the deflecting mirror assembly of Figure 2. The far field of the light source; and Figure 7 shows schematically the far field of the light source in the optical path downstream of the deflecting mirror assembly of Figure 5.

The projection exposure apparatus 1 for lithography, which is schematically shown in FIG. 1 in a meridional section, includes a light source 2 to provide illumination light 3. Light source 2 is an EUV source that produces light having a wavelength in the range of 5 nm and 30 nm. Here, the light source may be an LPP (Laser Excitation Plasma) source, a DPP (Gas Discharge Excited Plasma) source, or a source based on synchrotron radiation, such as a free electron laser (FEL).

The transmission optical unit 4 is used to guide the illumination light 3 starting from the light source 2. The transmission optical unit comprises a concentrator 5 (which is shown only for its reflection effect in Figure 1) and a transmission facet mirror 6 (which is also referred to as a first facet mirror). The concentrator 5 can be a Wolter type concentrator. The concentrator 5 can also be implemented as an elliptical mirror. The intermediate focus 5a (refer to FIG. 2) of the illumination light 3 is disposed between the concentrator 5 and the transmission facet mirror 6. For example, in the region of the intermediate focus 5a, the numerical aperture of the illumination light 3 is NA = 0.16 or 0.22. The NA at the intermediate focus 5a is at most 0.3 and may also have a value in the range of 0.17, 0.18 or 0.19, for example.

The deflecting mirror assembly 5b (which will be explained in more detail below) is disposed directly downstream of the intermediate focus 5a in the beam path of the illumination light 3.

The illumination preset facet mirror 7 is arranged downstream of the transport facet mirror 6 and therefore also downstream of the transport optical unit 4. The optical components 5 to 7 are members of the illumination optical unit 8 of the projection exposure apparatus 1. In a specific embodiment of the illumination optics unit 8, the illumination preset facet mirror 7 can be arranged in the pupil plane of the illumination optics unit 8 or in its region, while in the illumination optics In another embodiment of the element 8, the illumination preset facet mirror 7 can also be configured to be at a distance from the pupil plane of the illumination optics unit 8.

The mask 9 is disposed in the object plane 10 of the projection optical unit 11 downstream of the projection exposure apparatus 1, and is disposed downstream of the illumination preset pupil mirror 7 in the beam path of the illumination light 3. The projection optical unit 11 is shown in a very simplified manner in FIG. 1 by a dashed boundary line, which in each case is a projection lens.

To simplify the description of the positional relationship, a Cartesian xyz-coordinate system will be used below. In Figure 1, the x-direction extends perpendicular to the plane of the drawing and extends in the figure. In Figure 1, the y-direction extends to the right. In Figure 1, the z-direction extends downward. The coordinate systems used in the figures each have an x-axis extending parallel to each other. The z-axis range of these coordinate systems follows the individual main directions of the illumination light 3 in the individual considered pattern.

The illumination optics unit 8 serves to illuminate the object field 12 on the reticle 9 in the object plane 10 in a defined manner. The actual illuminated illumination field may be larger than the object field 12 or may coincide with the object field 12. The object field 12 has an arcuate or partially circular shape and is constrained by two mutually parallel arcs and two straight edge edges, the two edges extending in the y direction with a length y ₀ and spaced apart from each other in the x direction x ₀ . The aspect ratio x ₀ /y ₀ is 13 to 1. In the alternative and also possible object field 12 example, the edge profile is rectangular rather than curved.

The reticle 9 is supported by the reticle holder 12a, which is coupled back to the object displacement driver 12b. By the object displacement driver 12b, the reticle holder 12a can be displaced in a controlled manner along the y-direction along with the reticle 9.

The projection optical unit 11 is only partially and briefly shown in FIG. The object side numerical aperture 13 and the image field side numerical aperture 14 of the projection optical unit 11 are shown. Other optical components (not shown in FIG. 1) for guiding the projection optical unit 11 of the illumination light 3 between the optical components 15, 16 are tethered to the optical components 15, 16 shown in the projection optical unit 11. In the meantime, it can be implemented as a mirror that reflects EUV illumination light 3, for example.

The projection optical unit 11 images the object field 12 on the wafer 19 (which is the same as the photomask 9 The image field 17 of the image plane 18 is carried by the holder 20 and is functionally coupled to the wafer displacement driver 21. The mask holder 12a and the wafer holder 20 are movable in the x direction and the y direction by the displacement drivers 12b, 21.

The transmission facet mirror 6 has a plurality of transmission facets, which are not shown in the drawings. The transmission facet mirror 6 can be implemented as a MEMS mirror. The transport planes are grouped into a plurality of transport pupil groups during the projection operation, which are not described in any more detail.

In general, the transmission facet mirror 6 has a region that is struck by the illumination light 3 and may have an x/y aspect ratio of less than one. Furthermore, the value y/x of the aspect ratio can be at least 1.1 or even larger.

In a specific embodiment of the illumination optics unit having the illumination preset facet mirror 7 disposed in the pupil plane, the x/y appearance ratio of the transmission face group has at least an x/y appearance ratio to the object field 12. The same size. In the illustrated implementation, the x/y appearance ratio of the transmission face group is greater than the x/y appearance ratio of the object field 12. The transmission face group has a form of a local circular curved group edge similar to the edge form of the object field 12. Further details regarding the design of the transmission facet mirror 6 can be found in WO 2010/099 807 A.

Each of the transmission face groups directs the illumination light 3 of the portion to partially or completely illuminate the object field 12.

The transmission pupil is a micromirror that can be switched at at least two tilted positions. The transmission face can be implemented as a micro-mirror that can be tilted about two mutually perpendicular axes of rotation. The transmission facets are arranged such that the illumination preset facet mirror 7 is illuminated with a predetermined edge form and a preset correlation between the transmission face and the illumination preset face of the illumination preset facet mirror 7 Also not shown in the figure. For details regarding specific embodiments of the illumination preset facet mirror 7 and the projection optics unit 11, reference is made to WO 2010/099807 A. The illumination preset facets are micromirrors that can be switched at at least two tilted positions. The illumination preset face can be implemented as a micromirror that can be tilted continuously and independently around two mutually perpendicular tilt axes, ie the illumination preset face can be placed in a plurality of different tilt positions, in particular when illuminated The preset facet mirror 7 is disposed in the illumination optical unit When the planes of the pupils are at a distance apart.

Figure 2 shows in detail the beam path of the illumination light 3 in the region of the deflecting mirror assembly 5b, which is arranged directly downstream of the intermediate focus 5a in this beam path. The deflecting mirror assembly 5b is disposed upstream of the transmitting facet mirror 6 in the beam path of the beam 22. The deflecting mirror assembly 5b is embodied such that it deflects the centroid rays of the illumination beam 22 by at least 10°. Centroid rays of the illumination beam incident on the deflecting member 5b of the reflector assembly 22 be marked as S _in FIG. 2 in. The centroid rays of the illumination beam 22 reflected by the deflecting mirror assembly 5b (i.e., exiting from the deflecting mirror assembly 5b) are designated _Sout in FIG. Figure 2 also shows the deflection angle a, which is the angle at which the centroid ray S is deflected when reflected by the deflecting mirror assembly 5b. In the particular embodiment of Figure 2, the deflection angle a is about 25°. Other deflection angles α of at least 10° are also possible, for example a deflection angle α of at least 15°, at least 20°, or a deflection angle α of more than 25° (for example equal to 30° or 35°).

The deflecting mirror assembly 5b of Figure 2 has two mirrors 23, 24 for tangential incidence, which is also referred to hereinafter as a GI (tangential incidence) mirror. The mirror for tangential incidence is such that the angle of incidence to illumination light 3 is greater than 45° and may be greater than 60°, 65° or 70° and may, for example, be in the region between 70° and 85° or at 70° and 88° or 89 Between the areas of the mirror. The GI mirrors 23, 24 are embodied as hyperbolic mirrors, i.e. they have a reflective surface corresponding to the section of the rotating hyperboloid. The GI mirrors 23, 24 have a coating that is highly reflective to the illumination light 3.

Each of the two GI mirrors 23, 24 reflects a dedicated partial beam 25, 26 of the overall illumination beam 22. The two partial beams 25, 26 are directly connected to each other downstream of the deflecting mirror assembly 5b in the beam path, i.e. their distance from each other is practically negligible.

The divergence of the overall illumination beam 22 after reflection by the deflecting mirror assembly 5b corresponds to an effective numerical aperture NA _eff which may be increased by at least 10% or by at least 10% compared to the numerical aperture at the intermediate focus 5a, or may be It is the same. This effective numerical aperture NA _{eff is} derived from the angle between the starting centroid ray S _out and the outer edge ray 27 of the overall illumination beam 22 after reflection by the deflecting mirror assembly 5b. Thus, the angle of the edge ray of the reflected illumination beam 22 relative to the centroid ray _Sout will constitute a measure of NA _eff . In the particular embodiment of Figure 2, the effective numerical aperture NA _eff has a value of 0.16.

Thus, the deflecting mirror assembly 5b not only causes centroid ray deflection (as explained above) but also increases or decreases the effective numerical aperture of the intermediate focus. After deflecting the mirror assembly 5b, it is possible to use the downstream optical component of the illumination optics unit 8, which is prepared for a light source having an intermediate focal point having a numerical aperture corresponding to one of the effective numerical apertures.

The individual rays of the illumination beam 22 are reflected exactly once by the GI mirrors 23, 24 of the deflecting mirror assembly 5b, respectively. Each of the individual rays is reflected by a single one of the GI mirrors 23, 24. Therefore, the same individual rays in the illumination beam 22 do not continuously strike the GI mirrors 23, 24.

Figure 6 shows the far field 28 of the light source 2, which is recorded in the area of the transmission facet mirror 6 in the xy plane view. Figure 6 also shows the edge profile 6a of the transmission facet mirror 6. Each of the two GI mirrors 23, 24 will cause a far field intensity distribution (i.e., a far field intensity distribution without the deflection effect of the GI mirrors 23, 24) occurring at the beginning to be parallel to one of the xz-planes, respectively. The mapping of the mirror plane. The two mirror planes are labeled 29 and 30 in Figure 6. The far-field distribution of the deflection effect of the approximately annular non-GI mirrors 23, 24 (the outer edge contour 31 of the far-field distribution is indicated by the dashed line in Fig. 6) is composed of two semi-rings 32, 33 (its ring The center Z is far from each other) constructed far field intensity distribution.

Other embodiments of the deflecting mirror assembly, which can be used to illuminate the optical unit 8 instead of the deflecting mirror assembly 5b shown in Figures 1 and 2, will be explained below using Figures 3 through 5 and Figure 7. Components corresponding to components that have been explained above with reference to Figures 1, 2, and 6 have the same component symbols and will not be discussed in detail.

The deflecting mirror assembly 34 shown in Fig. 3 is in principle identical to the deflecting mirror assembly 5b shown in Figs. 1 and 2, except for a slightly smaller deflection effect having a deflection angle α of about 20°. the design of.

Fig. 3 schematically shows an installation space 35 for the light source side assembly in the intermediate focus area and an installation space 36 for the left GI mirror 23 of Fig. 3. This installation space 36 is located Between the GI mirrors 23, 24, it is relatively limited.

Regarding its optical effect, that is, first with respect to the centroid ray deflection and then zooming in or out to the effective numerical aperture NA _eff with respect to the intermediate focus NA, another deflecting mirror assembly 37 shown in FIG. 4 corresponds to that shown in FIG. The mirror assembly 34 is deflected. In contrast to the deflecting mirror assembly 34, the GI mirror 24 on the right in FIG. 4 deflects away from the main component by a distance A from the illumination component partial beam 26 assigned to the other illumination light partial beam 25 in the y direction. . The two open cones of the partial beams 25, 26 will be spaced apart by this distance. Therefore, the installation space 36 available for the GI mirror 23 on the left-hand side in FIG. 4 will increase. Therefore, the partial light beams 25, 26 reflected by the GI mirrors 23, 24 are spaced apart from each other in the region of the mirrors 23, 24.

FIG. 5 shows another embodiment of a deflecting mirror assembly 38. This deflecting mirror assembly 38 has a total of four GI mirrors 39, 40, 41, 42 whose effect substantially corresponds to the effects of the two GI mirrors 23, 24 of the particular embodiment of Figures 2 through 4. Each of the GI mirrors 39-42 reflects the exclusive partial beam 43, 44, 45, 46 of the overall incident illumination beam 22. Each of these partial light beams 43 to 46 is deflected by a single one of the GI mirrors 39 to 42. Here, each individual ray system of the overall illumination beam 22 undergoes a single reflection.

In the deflecting mirror assembly 38, the deflection angle α is about 19°.

Figure 7 shows the far field 47 of the position at which the illumination light 3 is deflected by the deflecting mirror assembly 38 after transporting the facet mirror 6. Due to the mapping effect of the GI mirrors 39 to 42 on the four mirror planes 48, 49, 50 and 51 parallel to the xz-plane, the far field (which is again approximately circular at the beginning) is now composed of four corresponding maps or The folded partial annular portions 52, 53, 54 and 55 are constructed. The annular portions 52 to 55 of these portions are again disposed within the edge contour 6a of the transmission facet mirror 6. Compared to the far field 28 of FIG. 6, the far field intensity distribution of the far field 47 has a greater similarity to the originally approximate annular far field of the light source 2 downstream of the concentrator 5.

In Figures 6 and 7, arrows 56 (which are respectively emitted from the center of the far field distribution 28 or 47) mark a point of the far field distribution 28 or 47 which is transmitted by the illumination light 3 to the facet mirror 6 The edge contour 6a has the largest distance from this center. Since far field 47 has far field than far field 28 The annular initial intensity distribution has a greater degree of similarity, so the length of the arrow 56 is shorter when comparing the far fields 28 and 47. With regard to the kneading plane switching angle required on the transmission facet mirror 6, the far field 47 produced by the four GI mirrors 39 to 42 can be correspondingly more advantageous than the far field 28.

3‧‧‧Lights

5a‧‧‧Intermediate focus

5b‧‧‧ deflecting mirror assembly

22‧‧‧ illumination beam

23‧‧‧GI mirror

24‧‧‧GI mirror

25‧‧‧Partial beam

26‧‧‧Partial beam

27‧‧‧Outer edge ray

‧‧‧‧ deflection angle

S _in ‧‧‧centroid ray

S _out ‧‧‧centroid ray

Claims (14)

An illumination optical unit for illuminating an illumination field, wherein an object to be imaged is configurable, including at least one facet mirror, including a deflecting mirror assembly upstream of the facet mirror In a beam path of an illumination beam, wherein the deflection mirror assembly is embodied such that it deflects a centroid beam of the illumination beam by at least 10°, wherein the deflection mirror assembly has at least two mirrors For tangential incidence, each of which reflects a dedicated partial beam of the overall illumination beam. The illumination optical unit of claim 1, wherein the deflecting mirror assembly is disposed downstream of an intermediate focus in a beam path of the illumination beam. The illumination optical unit of claim 1 or 2, wherein the deflecting mirror assembly is embodied as a numerical aperture covering the intermediate focus of at most 0.3. An illumination optical unit according to any one of claims 1 to 3, wherein the divergence of the overall illumination beam corresponds to an effective numerical aperture after reflection of the deflection mirror assembly. The effective numerical aperture is reduced by at least 10% compared to a numerical aperture of the intermediate focus. The illumination optical unit of any one of clauses 1 to 4, wherein the deflecting mirror assembly has more than two mirrors for tangential incidence. An illumination optical unit according to any one of claims 1 to 5, wherein at least one of the mirrors for tangential incidence is embodied such that it causes a far field intensity distribution. Mapping. An illumination optical unit according to any one of claims 1 to 6, wherein at least one of the mirrors for tangential incidence is embodied as a hyperbolic mirror. An illumination optical unit according to any one of claims 1 to 7, wherein the partial light beams reflected by the mirrors for tangential incidence are in the region of the mirrors. They are separated by a distance. An illumination system comprising the illumination optical unit of any one of claims 1 to 8 and comprising a concentrator as a first optical component in a beam path of an illumination source to illuminate the illumination lightguide Lead to the middle focus. The illumination system of claim 9 is characterized by an illumination source. An optical system comprising the illumination optical unit of any one of claims 1 to 8 and comprising a projection optical unit for imaging at least a portion of the illumination field to an image field. A projection exposure apparatus comprising the optical system of claim 11 and comprising an illumination source. A method for generating a microstructured component, comprising the following method steps: Providing a reticle, providing a wafer having a coating that is sensitive to illumination light, - projecting at least a portion of the reticle with the aid of a projection exposure apparatus as described in claim 12 To the wafer, the photo-sensitive layer exposed on the wafer by the illumination light is developed. An assembly produced by the method of claim 13 of the patent application.