DE10329141A1 - Extreme ultraviolet illumination system for microlithography, propagates chief ray between pupil and field facet mirrors, and between pupil facet mirror and reflective element, such that propagated ray are opposite and parallel - Google Patents

Abstract

The chief light ray (6) propagates from the field facet mirror (3) to pupil facet mirror (5), and the chief ray (8) propagates from pupil facet mirror to reflective element (19) positioned in a plane of field facet mirror, such that the chief ray are in opposite direction from one another and parallel to each other. Independent claims are also included for the following: (1) projection exposure system; and (2) method of producing microelectronic component.

Description

The The invention relates to a lighting system, in particular for lithography with wavelengths ≤ 193 nm, where the lighting system at least one light source, a collector and a double-facetted optical component and one EUV projection exposure system is assigned.

Around the structure widths for To be able to further reduce electronic components, in particular in the submicron range, it is necessary to change the wavelength of the for the Microlithography of light used to reduce. It is conceivable the use of light with wavelengths ≤ 193 nm, for example lithography with soft X-rays, the so-called EUV lithography.

EUV lithography is one of the most promising future lithographic techniques. Wavelengths in the range of 11-14 nm, in particular 13.5 nm, are currently being discussed as wavelengths for EUV lithography with a numerical aperture of 0.2-0.3. The image quality in EUV lithography is determined on the one hand by the projection lens and on the other hand by the illumination system. The illumination system is intended to provide the most uniform possible illumination of the field plane in which the structure-carrying mask, the so-called reticle, is arranged. The projection lens images the field plane into an image plane, the so-called wafer plane, in which a light-sensitive object is arranged. Projection exposure equipment for EUV lithography are designed with reflective optical elements. The shape of the field of an EUV projection exposure apparatus is typically that of a ring field with a high aspect ratio of 2 mm (width) × 22-26 mm (arc length). The projection systems are usually operated in scanning mode, wherein the reticle in the field plane and the photosensitive object, typically a wafer, with a suitable photoresist in the image plane in each case are moved synchronously. Concerning EUV projection exposure equipment, reference is made to the following publications:
W. Ulrich, S. Beiersdörfer, HJ Mann, "Trends in Optical Design of Projection Lenses for UV and EUV Lithography" in Soft-X-Ray and EUV Imaging Systems, WM Kaiser, RHStulen (Hrsg), Proceedings of SPIE, Vol. 4146 (2000), pages 13-24 and
M.Antoni, W. Singer, J. Schultz, J.Wangler, I.Escudero-Sanz, B.Kruizinga, "Illumination Optics Design for EUV Lithography" in Soft X Ray and EUV Imaging Systems, WMKaiser, RHStulen (eds) , Proceedings of SPIE, Vol.4146 (2000), pages 25-34
the disclosure of which is incorporated in full in the present application.

When Lighting systems that meet the requirements of EUV lighting in special way, Lighting systems have emerged which are the generic ones Features of claim 1. A disadvantage of the known system however, is that the components of a common EUV lighting system for Collecting the light from the light source, the spectral filtering and for shaping a lit field in the field level also for the formation of an advantageous filling of the exit pupil of the lighting system occupy a large amount of space.

The The object of the invention is an EUV lighting system such that a spectrally pure and advantageously designed Illumination of the field plane and the exit pupil of the illumination system with simultaneous compact design and simplified possibility for cleaning of dirt-prone optical components is reached.

The Inventors have recognized that a particularly advantageous folding geometry for EUV lighting systems This consists of the beam path in the region of the double-faceted To fold elements in itself.

The Double faceted element receives light over one first beam path, which from the light source or an image the light source goes out and directs this into a second beam path forming a plurality of secondary light sources. Near this secondary Light sources is the second optical element with second Grid elements. The second optical element with second raster elements outgoing third beam path is in the direction of the first optical Elements with first grid elements steered. There is a first reflective optical element which according to the invention substantially in the plane of the first optical element with first raster elements and positioned directly adjacent to the first raster elements is. The first reflective optical element reflects that of the second optical radiation coming onto other optical elements, which, like the first reflective optical element itself, is part of the second optical component, which in particular for forming a advantageous illuminated field in the field level is used. typically, these are a second reflective optical element and a grazing-incidence mirror.

To achieve a particularly compact construction, the first and second and / or second and third beam paths are in opposite directions and run essentially parallel to one another. This means that the averaged heavy beam over all light rays of the first beam path and the averaged heavy beam have opposite directions over all light beams of the second beam path and run parallel to each other except for a slight deviation. Alternatively or additionally, this condition can also be fulfilled for the second and third beam path. As small deviations from the parallel course angle deviations of <12 ° are considered, but an angular deviation of ≤ 5 ° is preferable, since this is advantageous both for the space reduction as well as for an advantageous design of the grid elements.

Especially Therefore, an arrangement of the first reflective optical is preferred Elements in the central region of the first optical element with first raster elements. This is particularly advantageous if this area from the first beam path between the light source or an intermediate image of the light source and the first optical Element with first raster elements is not illuminated. As The inventors have realized this is the case when as a collector to collect the light from the light source grazing-incidence mirror be used, in particular in the form of a nested collector, which below a certain aperture no light input for the lighting system deliver. This can further be achieved through the use of central apertures or by combining central apertures with nested collectors be effected.

When Result thus arises in the region of the first optical element with first raster elements a substantially circular illumination, so that the first raster elements only in this illuminated area be attached and in their center an area is left out, in the invention according to the first reflective optical element for reflection of coming from the third beam path Light is attached.

In an advantageous embodiment of the invention is between the Collector and the first optical element with first raster elements a combination of a grating spectral filter and a diaphragm device used for spectral filtering in the lighting system. in this connection will typically be an image of the light source in the area of the aperture device trained, with the different diffraction orders spread out spatially. The picture the chosen one Diffraction order is then held in the subsequent beam path according to the invention used by the light source itself. Again, through the use occurs a collector that is only above a certain minimum aperture Collects light and advantageously equipped with a central panel is, the above-mentioned shading effect on the first optical Element with first raster elements on. So that also here the said space gain by the integral fold of the second and third beam path in the most preferred manner by the positioning of the first reflective optical element in the region of this central Shading succeeds.

In a further development of the inventive concept may be another Intermediate image of the light source in the region of the second optical element with second raster elements are generated. In a particularly preferred Embodiment of the invention, the beam path, starting from this image of the light source and the first optical element with incoming first raster elements, by one in the second optical Element with second grid elements attached passage or Aperture passed. Preferably, this passage is central in the second optical element attached with second raster elements. Thus lies with this embodiment a further internal fold in the beam path in the region of the double faceted one Elementes, wherein the first to the second and the second to the third Beam path in opposite directions and run essentially in parallel are. The substantially parallel beam paths result again from the consideration of the heavy jets, which essentially parallel or have only slight angular deviations. In an advantageous embodiment, these angular deviations are less as 5 °.

Further Variants are possible in which the first and second intermediate image by the light source itself is replaced or alternatively only a first intermediate image of the light source is formed and this in the region of the passage in the second optical element comes to rest with second raster elements.

The Insich folds according to the invention of the beam path in the region of the double-facetted element a particularly compact design of the lighting system. Next The space gain is due to the folding geometries shown possible, additional mechanical and electronic components and in particular cleaning chambers to use in advantageous positioning in the lighting system. The for this advantageous folding geometry formed images of the light source can additionally through the use of grating spectral filters and apertures for the spectral Filtering of the illumination light can be used.

The Invention will be described below by way of example with reference to the drawings become.

It demonstrate:

1 EUV illumination system, wherein the first reflective optical element of the second opti component in the area of the central shading of the first optical element with raster elements;

2 first optical element with first raster elements and Zentralabschattung;

3 an illumination system having the first reflective optical element of the second optical component positioned in the central shading of the first optical element with first raster elements and a first intermediate image of the light source in the plane of the second optical element having second raster elements and a beam path passing through this element;

4 Illumination system with an analogue beam path as in 3 and an additional normal incidence concave mirror after the first intermediate image of the light source and the formation of a second intermediate image of the light source in the region of the second optical element with second raster elements.

5 Illumination system with an analogue beam path as in 4 and a cleaning chamber between the first intermediate image and the second intermediate image of the light source

6 Arrangement of the first reflective optical element in the immediate vicinity of the first optical element with first raster elements and opposite to the intermediate image of the light source.

7 Arrangement of the first reflective optical element in the immediate vicinity of the first optical element with first raster elements and positioned on the side of the intermediate image of the light source.

8th EUV lithography system for microlithography;

In 8th The typical structure of an EUV lithography system for microlithography is shown. A reticle or a mask 104 is doing so at the field level 13 a projection exposure system positioned and by means of a reduction optics on the image plane 130 which typically includes a wafer provided with a photosensitive material 106 located. 7 shows an example of a projection lens consisting of six individual mirrors 128.1 to 128.6 , Also shown is an ideally telecentric illumination of the image plane 130 , ie the main ray of a ray bundle, which from a field point of the field plane 13 goes out, cuts the picture plane 130 perpendicular. Furthermore, the projection lens points 126 an entrance pupil that generally coincides with the exit pupil of the illumination system.

8th further shows the typical construction of an EUV lighting system which is a light source 1 for wavelengths ≤ 193 nm. Preferably, ArF excimer lasers with a light wavelength of λ = 193 nm or F ₂ lasers which provide a wavelength of λ = 157 nm are used for this purpose. However, laser-plasma X-ray sources which have a wavelength of λ = 5 to 20 nm are particularly preferred. Alternatively, a synchotron source with wavelengths λ = 10 to 15 nm can be used.

The of the light source 1 outgoing radiation is in a first collector unit 9 collected. 8th shows in a schematically simplified manner a nested collector, which is composed of several collector shells and is designed as a Woltersystem with two reflections. In such a collector mirror systems are used, which consist for example of a combination of hyperboloidal and ellipsoidal mirror and whose principle is mentioned in the literature for the first time in the annals of physics 10, 94-114, 1952, the disclosure of this document is fully in the present Registration is included.

This first collector unit 9 acts collimating and forms an intermediate image Z of the light source. In an advantageous embodiment of the invention is between this intermediate image Z and the light source 1 a grid element 200 used for spectral filtering of the illumination system. In general, a spectrally pure illumination of the field level 13 desired, but it is often not possible to use narrow-band light sources or laser systems for this purpose, since otherwise from the light source 1 to be taken light output would decrease too much. Instead, a certain spectral dispersion is allowed and additional elements with filtering effect are used in the lighting system.

This in 8th schematically illustrated grid element 200 based on a spectral separation by diffraction of the light and by sorting out unwanted diffraction orders, in the present case, in particular, light of the 0 diffraction order with a wavelength above 100 nm is rejected. For this purpose, one or more physical diaphragms in the diaphragm plane are preferably arranged after the grating element 200 in the region of the first intermediate image Z of the light source that forms 202 arranged, which are formed in a particularly preferred embodiment as staggered and cooled panels.

A particularly preferred spectral filtering is achieved in that in addition to the grating spectral filter 200 at least one mirror is used with a multilayer system. Such a mirror may for example be part of the collector. By adding a matched mirror with a multilayer system, the useful wavelength of 13.5 nm and wavelengths above 100 nm can be extracted from the emission of the light source. In combination with a grating spectral filter 200 , which is set so that just the wavelength range of 7 to 13.5 nm is selected, results in a spectrally particularly pure illumination.

Since the grid element 200 is in the first collector unit in the subsequent convergent beam path, the optical effect of the grating is observed. One way to avoid the resulting difficulties is to use a grid element 200 , which consists of several individual lattices. These single lattices are applied on a curved support surface. By way of example, these individual gratings can be formed as blazed gratings which have reflective layers of ruthenium or other metallic layers such as palladium or rhodium, with a high efficiency η (-1) for the reflectivity of typical wavelengths of λ = 13.5 nm. In particular, irradiation with wavelengths greater than 100 nm can be suppressed by means of such a grating-diaphragm combination, so that not only the improved quality of the illumination but also the thermal stress on all components of the EUV illumination system and the subsequent projection exposure apparatus and the mask used 11 in the field level 13 reduced.

8th also sketches a lighting system, which as a double-faceted lighting system according to the US 6,198,793 B1 is formed, the content of this document is fully incorporated in the present application. Such a system comprises a first optical element with first raster elements 3 , which is also called field facet mirror 3 referred to as. The beam path is followed by a second optical element with second raster elements 5 which is usually pupil facet mirror 5 is called.

Field and pupil facet mirror 3 . 5 serve to illuminate a field in the field level 13 and the design of the illumination in the exit pupil of the illumination system. The effect of each field honeycomb is to form an image of the light source 1 is formed, wherein formed by the different inclination angle of the field facets a plurality of so-called secondary light sources. As in 8th shown, that of the first intermediate image Z of the light source 1 Outgoing and widening beam path through the field facets in the area of the pupil facet mirror 5 be focused on the secondary light sources. The necessary collimating effect of the field facets can be achieved either by concave shaping of the mirror carrier of the plurality of field facets and by a corresponding tilting of the field facets. Of the subsequent optical elements, these secondary light sources are imaged as tertiary light sources in the exit pupil of the illumination system.

Furthermore, each field honeycomb will pass through the facets of the pupil facet mirror 5 and the subsequent optical elements of the second optical component, which in the example 8th from the three optical elements first reflective optical element 19 , Second Reflective Optical Element 21 and the grazingincidence mirror 23 exist, in the field level 13 displayed. The superimposed images of the field facets serve to illuminate a mask 11 in the field level 13 , where typically, starting from rectangular or arcuate field facets, an illumination in the field plane 13 in the form of a ring field segment arises. In general, the microlithography system is designed as a scanning system, so that the mask 11 in the field level 13 and a wafer 106 in the picture plane 130 be moved synchronously to effect an illumination or an exposure.

In 8th is also the heavy jet 4 drawn as a connecting line of the geometric centers of all optical surfaces. The heavy beam between field facet mirror 3 and pupil facet mirror 5 with the reference number 6 and the heavy beam between pupil facet mirror 5 and first optical element 19 with the reference number 8th are inclined to each other with an angle of about 10 °.

When using nested reflectors 9 of the above kind, only light above a certain numerical aperture can be collected. Consequently, the field facet mirror, as in FIG 2 shown, no facets in its central area, as this region is not illuminated. 2 also shows the summary of the plan facets to several blocks 500.1 to 500.10 that group around this shaded area.

Without the field-forming, gracing-incidence mirror 23 For example, the field facets may also trivially have a shape corresponding to the ring field shape, ie be arcuate.

Even with normal-incidence collectors, the formation of a central shading 502 in the Illumination of field facets possible. This results, for example, from a light source which itself produces a central shading, so that no facets are arranged here in the central region of the field facet mirror.

To 1 is inside the nested collector 9 a central aperture 204 used, which blocks the stray light in the central region of the collector and additionally ensures that on the field facet mirror 3 a central area is shaded. According to the invention, this serves in 2 central shading shown 502 to that first reflective optical element 19 the second optical component 7 to absorb what is in 1 is shown in a schematic way. Herein lies the difference to the beam path according to 8th as commonly used in an EUV lighting system.

In detail shows 1 after the intermediate image of the light source Z, a first beam path 14 from the intermediate image of the light source to the field facet mirror 3 , a second beam path 15 from the field facet mirror 3 to the pupil facet mirror 5 which is essentially opposite to the third beam path 16 from the pupil facet mirror 5 to the first reflective optical element 19 , which is located in the central shading of the field facet mirror 3 located. Here is the first reflective optical element 19 associated with the second optical component. The subsequent beam path is substantially coincident to that of 8th in which via the second reflective optical element 21 and the grazing-incidence mirror 23 the beam path to the field level 13 steered and the field illumination is formed.

In the example shown is the heavy jet 6 between field facet mirrors 3 and pupil facet mirror 5 exactly parallel to the heavy jet 8th between pupil facet mirror 5 and first optical element. The heavy beams 6 and 8th are in opposite directions and do not need to be exactly parallel, but may differ as far as the positioning of the first optical element 19 within the central shading 502 the field facet mirror 3 allowed. It is particularly advantageous if the heavy beams 6 and 8th each other have an angle of not greater than 5 °.

The inclusion of a first reflective optical element 19 in the central shading 502 of the field facet mirror 3 allows a particularly compact design. Furthermore, due to the substantially parallel beam guidance between field facet mirror and pupil facet mirror, a particularly simple assignment of the field facets to the pupil facets is possible, whereby the buildability and coating of the double-facetted element is facilitated. A further advantage is that the angle of inclination of the facet surfaces and the angles of incidence at the surface are reduced as a result of the resulting smaller deflection angle of the pupil facets. This increases the reflectivity while reducing possible mutual Abschattungsverluste. The reduced space also has a positive effect on the volume, which is lower, which is particularly advantageous for EUV exposure systems, which yes the system must be evacuated.

Due to the invention folding geometry a particularly compact design of the lighting system is possible. At the trained intermediate images, it is also possible to make a separation of the illumination system in compartments and so to realize a modular design of the lighting system. A separation light source with the collector and the spectral filter and the aperture arrangement in a separate compartment 300 makes it possible to limit the emanating from the light source pollution spatially. The optical elements of the double-facetted element and the second optical component in such a design result in a particularly compact and structurally simplified module, which adjoins the illumination module in the region of the intermediate image. In this case, different atmospheres can be set in these two modules, whereby the risk of emanating from the light source pollution can be limited to the subsequent optical components.

3 shows a further development of the idea according to the invention, in which the intermediate image Z of the light source is formed in a region which is in direct proximity to the rear side of the second optical element with second raster elements. In this case, it is possible to use components for collecting the light of the light source and for spectral filtering, which correspond to those from 1 correspond. Exemplary here is the use of a nested reflector 9 with a centrally positioned aperture 204 and a Spektralgitterfilter 200 with associated physical aperture in the aperture plane 202 shown. By forming an intermediate image on the back adjacent to the pupil facet mirror 5 and through a limited passage through the pupil facet mirror 5 It is possible that through the intermediate image of the light source to Feldfacettenspiegel 3 extending first heavy jet 4 opposite to the second of the field facet mirror 3 reflected back heavy jet 6 form and thus in addition to the folding of the invention between the second, between Feldfacettenspiegel 3 and pupil facet mirror 5 extending beam path with heavy beam 6 , and the third, from the pupil facet spiece gel 5 back reflected beam path with heavy beam 8th to achieve yet another third inner fold in the area of the double-facetted element. Alternatively, of course, only a folding of the shear beam 4 and 6 take place when the first optical element 19 not in the central shading of the field facet mirror 3 is arranged.

In addition to a further reduction of the installation space, the passage in the pupil facet mirror can be 5 for the first beam path 4 also as a physical aperture for filtering out unwanted diffraction orders. Thus, only the desired and the spectral grating 200 reflected spectral range through the passage in the pupil facet mirror 5 directed. Here, as in the embodiments described above, the field facet mirror 3 and pupil facet mirror 5 be designed so that the resulting thermal load is low. For example, a cooling can be provided for this purpose.

Special advantage of the embodiment 3 with the double convolution of the beam path is that now both the field and the pupil facets have lower angles of inclination and lower angles of incidence occur. Thus, the reflection losses are lower and there are fewer mutual shadowing of individual, adjacent facets with, for example, different angles of inclination. The channel assignment between field and pupil facets is therefore subject to fewer restrictions.

Also, in such a system, the distances between field and pupil facets are more likely to be interpreted as being approximately equal in length, as opposed to, for example 8th where they are different in length due to the oblique beam path. In the advantageous embodiment 3 Thus, with the same radii of curvature of the facet mirrors, the variation of the image scales with which the individual field facets of the field facet mirror also vary 3 in the field level 13 be imaged, lower. The system is thus better correctable.

4 shows an evolution of in 3 illustrated inventive idea of a further convolution of the illumination geometry in the region of the double-facetted element. In this case, a first intermediate image of the light source Z1 in the region of the diaphragm plane 202 formed, so that by means of a physical aperture spectral filtering can be made. From there, the light passes, for example, via a normal incidence concave mirror with collimating effect 400 in a second intermediate image of the light source Z2, which on the back and in the immediate vicinity of the pupil facet mirror 5 lies. As a result, a double-folded optical path in the region of the double-facetted element is advantageously achieved, as well as a separate spectral filtering in conjunction with the first intermediate image of the light source. Thus, on the one hand, the thermal stress on the construction of the pupil facet mirror 5 The other is through the use of the normal incidence concave mirror 400 a further space-saving and thus advantageous folding of the beam path in the lighting system possible. The disadvantage of a reduction of the illumination intensity by the use of a further mirror, in particular one which is designed as a normal incidence mirror, is outweighed by several advantages. Furthermore, the additional normal-incidence mirror 400 which, as the first mirror coated with a multilayer, performs wavelength filtering and experiences high thermal load and contamination, is cooled more easily and can also be designed to be movable in a cleaning device for regular cleaning.

This is important because in particular the first and last optical surfaces of refractive systems, for example, are particularly at risk of contamination, because these are in the immediate vicinity z. B. to a source, a Mask or to be exposed wafer. About these can Impurities are introduced into the optical system. The High-energy radiation of the light sources ≤ 193 nm cause, for example the residual oxygen content is transformed by the radiation into ozone which, in turn, the surfaces of the optical elements, d. H. whose coating can attack and destroy.

Further can by residual gas concentrations such. B. hydrocarbons in the surrounding atmosphere the optical surface Contaminations on the optical surface form, z. B. by crystal formation or layers z. As carbon or carbon compounds.

The contamination may depend on the illuminance. In EUV lithography, one can use sources that emit a broadband spectrum. Even after a spectral filtering, z. B. with a grating spectral filter, there is a wide range of high-energy radiation. Particularly high is the load in the first optical components to the first multilayer mirror in an EUV system, since up there except the radiation at z. B. 13.5 nm, the broadband radiation of the source is present and thus the radiation exposure is maximum. The reflection loss on the first normal-incidence mirror in an illumination system of an EUV projection exposure apparatus is greatest because this mirror receives the greatest power density of the light source, but essentially only selectively due to the multiple coating at 13.5 nm. Any other radiation emitted by the EUV source is thus converted into absorption power. Carbon or carbon compounds are removed by periodically cleaning the mirrors, for example, by incorporating argon and oxygen under an RF plasma. With regard to the cleaning of contaminated optics, reference is made to the following publication:
F. Eggenstein, F. Senf, T. Zeschke, W. Gudat, "Cleaning of contaminated XUV-optics at Bessy II", Nuclear Instruments and Methods in Physics Research A 467-468 (2001) p 325-328
the disclosure of which is incorporated in full in the present application.

A However, such cleaning of the mirror is necessary at short intervals. As a result, the machine times are greatly reduced. So For example, it may be necessary to have the first normal-incidence Mirror in an EUV projection exposure system after about 20 To clean the operating hours again. This cleaning takes for example about 2 hours, that is 10% of the usage time.

The folding invention allows good accessibility of the first multilayer mirror and the formation of a compact cleaning chamber 410 as in 5 shown, with the cleaning chamber 410 from the chamber, such as the vacuum chamber of the remaining optical subsystem atmospheric, z. B. is separated by vacuum technology. In the separate from the rest of the optical subsystem cleaning chamber 410 For cleaning purposes, a certain gas concentration, eg. For example, preferably an oxygen concentration and / or an argon concentration, or a gas stream and other means for cleaning, such as a UV light source, an RF antenna for generating a high-frequency plasma, electrodes for applying fields or mechanical cleaning agents are introduced.

A Arrangement of the optical component to be cleaned in a separate Vacuum chamber has the advantage that the mirror by admixture a certain oxygen concentration during operation constantly itself can be cleaned and a complete cleaning only after longer periods becomes necessary. Due to the arrangement in a separate vacuum chamber, the remaining System, for example, before possible harmful Influences of Cleaning protected.

As in 4 shown by the inventive counter-rotating beam paths an advantageous space design, which, for example, to form a cleaning chamber 410 can be used. Outlined here 4 the beam path after the second intermediate image of the light source Z2. This corresponds to that embodiment, which in 3 was presented. In particular, a folding according to the invention by the opposition of the second beam path with heavy jet 6 from the field facet mirror 3 to the pupil facet mirror 5 in relation to the third beam path with heavy beam 8th from the pupil facet mirror 5 to the subsequent first reflective optical element 19 by positioning this first said reflective optical element 19 in the area of the central shading of the field facet mirror 3 reached. In 4 is indicated that this first reflective optical element also has a small offset to the center of the field facet mirror 3 can have.

In 5 a further embodiment of the invention is shown. Here, the second intermediate image Z2 of the light source 1 although adjacent and preferably in the plane of the pupil facet mirror 5 trained, the heavy jet 4 but not through a passage in the pupil facet mirror 5 guided. According to the invention, the heavy jets run 6 and 8 substantially parallel. Advantageously, these extend at an angle of not greater than 5 °.

Of course, only the first or second intermediate image of the light source Z1 or Z2 in the Pupillenfacettenplatte 5 come to rest, and the first reflective optical element 19 are adjacent or even spaced from the field facet mirror so that only the first beam path between intermediate image Z1 or Z2 of the source and field facet plate 3 and the pupil facet plate 5 run in opposite directions and almost parallel to each other. In the context of the invention, it is further provided, the first reflective optical element 19 also outside the central shading of the field facet mirror 3 but it continues to be essentially at the level of the field facet mirror 3 and in direct proximity to the first raster elements of the field facet mirror 3 is arranged. Such an arrangement is in the 6 and 7 shown. They also show that the intermediate image Z of the light source, which is here alternatively for the light source or for a second or further intermediate image of the light source, with a small offset to the center of the pupil facet mirror 5 but still in its immediate vicinity, can be positioned. The spacing can advantageously be chosen such that the angle of incidence of the heavy beam across all the beams at the facet mirrors is not more than 6 °, ie, the angles of incidence are reduced, whereby a simpler buildability and higher reflectivity can be achieved. Is the distance between the plane of the field facet plate or the first reflective optical Element and the plane of the pupil facet plate or the intermediate image of the source Z in about one meter, it follows that the centers of each adjacent optical elements is not greater than about 100mm, ie the center of the pupil facet plate 5 is less than about 100mm from the source Z intermediate image, or the center of the first reflective optical element is less than about 100mm from the center of the field facet plate so that angles of incidence of less than 6 ° are established.

Next the an EUV lighting system with a folded according to the invention Beam path, the invention also provides a projection exposure system for the EUV lithography with such a folded beam path and a method for producing microelectronic components for Available.

1

light source

3

first optical element with first raster elements

(Field facet mirror)

4, 6, 8

heavy beams

5

second optical element with second

grid elements

(Pupil facet mirror)

7

second optical component

9

first collector unit

11

structure-bearing mask

13

field level

14

first Beam path to the first optical element with

first grid elements

15

second Beam path from the first optical element with

first Raster elements to the second optical

element with second raster elements

16

third Beam path from the second optical element with

second Raster elements for the first reflective

optical element

17

secondary light source

18

passage through the second optical element with

second grid elements

19

first reflective optical element

21

second reflective optical element

23

grazing-incidence mirror

25

exit pupil of the lighting system

26

Beam tufts from second optical element with

second Raster elements to the second optical

component

27

exit pupil of the lighting system

30

first raster elements

32

second raster elements

102

second collector unit

104

mask

106

With a photosensitive material provided wafer

126

projection lens

128.1, 128.2, 128.3

mirror of the projection lens

128.4, 128.5, 128.6

130

image plane

200

grid element

202

stop plane

204

cover in the first collector unit

400

normal incidence concave mirror

410

cleaning chamber

500.1, 500.2, 500.3

Blocks with first raster elements

500.4, 500.5, 500.6

500.7, 500.8, 500.9

500.10

502

central shadowing

Z

intermediate image the light source

Z1

first Intermediate image of the light source

Z2

second Intermediate image of the light source

Claims (17)

EUV illumination system for lithography with wavelengths ≤ 193 nm with 1.1 of a light source ( 1 ); 1.2 a collector ( 9 ) for collecting the light source ( 1 ) outgoing radiation; 1.3 a double-faceted optical component comprising a first optical element with first raster elements ( 3 ) and a second optical element with second raster elements ( 5 ); 1.4 a second optical component, which follows the double faceted optical component and at least one first reflective optical element ( 19 ); 1.5 a first beam path ( 14 ) between the light source ( 1 ) or an intermediate image of the light source and the first optical element with first raster elements ( 3 ); 1.6 a second beam path ( 15 ) between the first optical element with first raster elements th ( 3 ) and the second optical element with second raster elements ( 5 ); 1.7 a third beam path ( 16 ) between the second optical element with second raster elements ( 5 ) and the first reflective optical element ( 19 ); characterized in that first and second beam path ( 14 . 15 ) and / or second and third beam path ( 15 . 16 ) are guided in opposite directions and essentially in parallel. EUV lighting system according to claim 1, characterized that the angular deviation of the opposing and essentially parallel guided Beam paths <12 °, preferably <6 ° and especially preferably ≤ 5 °. EUV lighting system according to one of claims 1 to 2, characterized in that the first reflective optical element ( 19 ) substantially in the plane of the first optical element with first raster elements ( 3 ) and substantially directly adjacent to the first raster elements. EUV lighting system according to claim 3, characterized in that the raster elements of the first optical element with first raster elements ( 3 ) around the first reflective optical element ( 19 ) are arranged around. EUV lighting system according to one of claims 1 to 4, characterized in that the collector ( 9 ) a central shading ( 502 ) having. EUV lighting system according to claim 5, characterized in that the collector ( 9 ) has at least one grazing-incidence mirror above a certain threshold value of the aperture radiation from the light source ( 1 ) collects. EUV lighting system according to claim 6, characterized in that the collector ( 9 ) is constructed as a nested collector according to the Woltersystem. EUV lighting system according to one of claims 5 to 7, characterized in that the first reflective optical element ( 19 ) substantially in the central shading of the first optical element with first raster elements ( 3 ) is arranged. EUV lighting system according to one of claims 1 to 8, characterized in that the first beam path ( 14 ) through a passage ( 18 ) in the second optical element with second raster elements ( 5 ) to be led. EUV lighting system according to one of claims 1 or 9, characterized in that in the direct vicinity of the second optical element with second raster elements ( 5 ) An intermediate image of the light source is formed. EUV illumination system according to one of claims 1 to 10, characterized in that for spectral filtering a grating spectral filter ( 200 ) in conjunction with a physical diaphragm positioned in the region of an intermediate image of the light source ( 1 ) is used to select a desired diffraction order. EUV illumination system according to claim 11, characterized in that as a physical diaphragm for selecting a desired diffraction order a passage in the second optical element with second raster elements ( 5 ) is used. EUV illumination system according to claim 13, characterized in that, by means of a normal-incidence concave mirror following the physical diaphragm which is used for the selection of a desired diffraction order, another intermediate image of the light source ( 1 ) is formed, that in the immediate vicinity of the second optical element with second raster elements ( 5 ) is positioned. EUV lighting system according to claim 1-13, comprising a normal-incidence concave mirror, which is movable. EUV lighting system according to claim 1-14, comprising a normal-incidence concave mirror, which is located in a cleaning chamber. Projection exposure apparatus, characterized that the projection exposure system is an EUV lighting system according to one the claims 1 to 15. Method for exposing to the production of microelectronic Components, characterized in that a projection exposure apparatus, an EUV lighting system according to one of claims 1 to 15, is used.