Optical components for use especially in the illumination system of a microlithographic projection exposure apparatus

Abstract

The invention relates to a group of optical components, in particular for use in an illumination device of a microlithographic projection exposure apparatus, comprising a first reflective component with a first reflective layer system and a second reflective component with a second reflective layer system, the first and second reflective components corresponding to each other in the shape of their optically active surface and for a given wavelength interval and a given angle of incidence of incident electromagnetic radiation, the spectral reflectance profile (r 1s (λ),r 1p (λ)) is the corresponding spectral reflectance profile (r 2s (λ),r 2p Unlike (λ), the spectral reflectance profile of the first reflective layer system relates to a set of optical components that describe the respective wavelength dependences of reflectance for s-polarized and for p-polarized radiation.

Description

[Technical field]

[0001] This application claims priority to German Patent Application No. 10 2021 210 491.6, filed September 21, 2021, the contents of which are incorporated herein by reference.

[0002] The invention relates to a group of optical components for use in particular in the illumination system of a microlithographic projection exposure apparatus. [Background technology]

[0003] Microlithography is used for the production of finely structured components, e.g. in integrated circuits or LCDs. The microlithography process is carried out in so-called projection exposure apparatus, which comprises an illumination system and a projection lens. In this case, the image of a mask (reticle), illuminated by the illumination system, is projected by the projection lens onto a substrate (e.g. a silicon wafer) that is covered with a light-sensitive layer (photoresist) and is placed in the image plane of the projection lens, in order to transfer the mask structure into the light-sensitive coating of the substrate.

[0004] In projection lenses designed for the EUV region, ie for example at wavelengths of about 13 nm or about 7 nm, mirrors are used as optical components for the imaging process due to the non-availability of suitable light-transmitting and refractive materials.

[0005] During operation of the projection exposure apparatus, it is necessary to set in the illumination system a specific polarization distribution in the pupil plane and / or in the reticle for the purpose of optimizing the imaging contrast, and it is also necessary to be able to carry out a change of the polarization distribution during operation of the projection exposure apparatus. Taking into account the so-called vector effect at relatively large values ​​of the numerical aperture (NA), the use of s-polarized light can therefore be advantageous in order to obtain the highest possible image contrast, especially in the case of projection exposure apparatuses imaging certain structures.

[0006] However, situations do occur during the operation of a projection exposure apparatus in which the use of unpolarized radiation is advantageous rather than operation with polarized radiation. By way of example, such a situation may arise when, despite high numerical aperture (NA) values, the structures to be imaged within the lithographic process are not linear structures or structures which otherwise define a preferred orientation, but structures without a preferred motion (e.g. contact holes). In this case, the use of linearly polarized radiation not only does not yield advantages, but may even prove to be disadvantageous as a result of the induction of undesired asymmetries.

[0007] In yet another related situation, when polarized radiation is supplied following the initial generation of unpolarized radiation by conventionally used EUV sources (e.g. plasma sources), in particular the necessary out-coupling of each undesired polarization component essentially results in losses of radiant flux, which further reduces the performance of the projection exposure apparatus.

[0008] Taking into account the above aspects, it is therefore also necessary in principle to be able to switch between an operating mode with polarized radiation and an operating mode with unpolarized radiation depending on the operating scenario of the projection exposure apparatus, in particular depending on the respective structure to be imaged.

[0009] However, the implementation of such a switch in a projection exposure apparatus designed to operate in EUV is made more difficult, firstly because the beam shape applicable for the beam input to or output from the illumination apparatus should be maintained from a practical point of view, and secondly because suitable transmissive polarization optical components, such as beam splitters, are not available in the relevant EUV wavelength range. However, polarization manipulation based on reflection below the Brewster angle, as is available in the EUV range, entails the introduction of one or more additional beam deflections and thus significant light losses, if at the same time an unchanged beam shape is to be ensured.

[0010] Regarding the prior art, reference is made, purely by way of example, to US Pat. No. 5,399,633, US Pat. No. 5,499,625, and non-patent document 1. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] DE 10 2008 002 749 A1 [Patent Document 2] DE 10 2018 207 410 A1 [Non-patent literature]

[0012] [Non-Patent Document 1] MY Tan et al.: "Design of transmission multilayer polarizer for soft X-ray using a merit function", OPTICS EXPRESS Vol. 17, No. 4 (2009), pp. 2586-2599 Summary of the Invention [Problem to be solved by the invention]

[0013] In view of the above, it is an object of the present invention to provide a group of optical components, in particular for use in an illumination system of a microlithographic projection exposure apparatus, which facilitates flexible switching between operation with polarized radiation and operation with unpolarized radiation without transmission losses. [Means for solving the problem]

[0014] This object is achieved by the features of independent claim 1.

[0015] The optical component group according to the invention, which is particularly suitable for use in an illumination system of a microlithographic projection exposure apparatus, comprises: a first reflective component having a first reflective layer system; a second reflective component having a second reflective layer system; the first reflective component and the second reflective component have corresponding optically effective surfaces; For a given wavelength interval and a given angle of incidence of the incident electromagnetic radiation, the spectral reflectance profile (r 1s (λ),r 1p (λ)) is the corresponding spectral reflectance profile (r 2s (λ),r 2p Unlike (λ), the spectral reflectance profile of the first reflective layer system represents the respective wavelength dependence of reflectance for s-polarized and for p-polarized radiation.

[0016] In particular, the invention is based on the idea of ​​replacing a reflective component located in the light beam path of an EUV illumination device with another reflective component having the same surface shape but a different reflective layer system, thereby realizing flexible switching in the illumination device between polarized and non-polarized operating modes depending on the application scenario and depending on the respective structure to be imaged in the lithography process, thereby avoiding additional beam deflections.

[0017] Within the meaning of the present application, an illuminator is understood to mean an optical system that illuminates a reticle with a defined spatial and angular distribution by appropriately reshaping the radiation of a real or virtual light source. In particular, an EUV illuminator according to the invention can receive the radiation of a plasma (i.e. a real light source) via a collector. In yet another embodiment, the EUV illuminator can also receive radiation from an intermediate focus (i.e. a virtual light source).

[0018] In accordance with the present invention, by providing two different interchangeable reflective components having different spectral reflectance profiles for s-polarized and p-polarized radiation but otherwise corresponding surface shapes, as described below, the overall shape of the beam path within the illumination system remains unchanged even after exchanging one component for the other to switch between polarized and unpolarized operation (i.e., switching between polarized and unpolarized illumination systems), and therefore no additional beam deflection with associated undesirable light losses is required.

[0019] In this case, the invention is based in particular on the insight gained by the inventor on the basis of comprehensive simulations that the spectral emission profile provided by each reflective layer system of a reflective component exchanged according to the invention, which applies respectively to s-polarized radiation and p-polarized radiation, can be shifted in a targeted manner by appropriate adaptation (e.g. thickness scaling of the individual layers forming the stack of the reflective layer system) to the relevant "transmission spacing" of the entire optical system (i.e. in particular the subsequent optical components in the beam path of the illumination device).

[0020] This targeted adjustment or shift of the spectral reflectance profiles applicable to s-polarized radiation and p-polarized radiation can furthermore be performed, in particular in the case of reflective components used in the "polarized operation" of an illumination or projection exposure apparatus, such that the respective maximum reflectance values ​​of the spectral reflectance profile applicable to s-polarized radiation, but not of the spectral reflectance profile applicable to p-polarized radiation, are located within the above-mentioned transmission interval of the optical system. In contrast, this targeted adjustment or shift of the spectral reflectance profiles applicable to s-polarized radiation and p-polarized radiation can be performed in the case of reflective components used in the "non-polarized operation" of an illumination or projection exposure apparatus, such that the respective maximum reflectance values ​​of both spectral reflectance profiles (i.e. both the spectral reflectance profile for p-polarized radiation and the spectral reflectance profile for p-polarized radiation) are located within the above-mentioned transmission range.

[0021] According to one embodiment, the first reflective layer system satisfies the following conditions: (λ 0 -Δλ 0 / 2)≧λ 1sl ,(λ 0 +Δλ 0 / 2)≦λ 1sr and (λ 0 -Δλ 0 / 2)≦λ 1pl or (λ 0 +Δλ 0 / 2)≧λ 1pr So that the wavelength λ 0is the width Δλ 0 For a given wavelength interval [(λ 0 -Δλ 0 / 2),(λ 0 +Δλ 0 / 2)], where the reflection profile of the first reflective layer system (r 1s (λ),r 1p (λ) 1sl and λ 1pl denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance of at least 50% of the maximum reflectance, and λ 1sr and λ 1pr denotes the longest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

[0022] According to one embodiment, the second reflective layer system satisfies the following conditions: (λ 0 -Δλ 0 / 2)≧λ 2sl ,(λ 0 +Δλ 0 / 2)≦λ 2sr and (λ 0 -Δλ 0 / 2)≧λ 2pl ,(λ 0 +Δλ 0 / 2)≦λ 2pr So that the wavelength λ 0 is the width Δλ 0 For a given wavelength interval [(λ 0 -Δλ 0 / 2),(λ 0 +Δλ 0 / 2)], where the reflection profile of the second reflective layer system (r 2s (λ),r 2p (λ) 2sl and λ 2pl denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance of at least 50% of the maximum reflectance, and λ 2sr and λ 2pr denotes the longest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

[0023] Advantageously, both reflective layer systems have a common spacing [(λ 0 -Δλ 0 / 2),(λ 0 +Δλ 0 / 2)].

[0024] Thus, according to one embodiment, the first reflective layer system satisfies the following conditions: (λ 0 -Δλ 0 / 2)≧λ 1sl ,(λ 0 +Δλ 0 / 2)≦λ 1sr and (λ 0 -Δλ 0 / 2)≦λ 1pl or (λ 0 +Δλ 0 / 2)≧λ 1pr and the second reflective layer system satisfies the following condition: (λ 0 -Δλ 0 / 2)≧λ 2sl ,(λ 0 +Δλ 0 / 2)≦λ 2sr and (λ 0 -Δλ 0 / 2)≧λ 2pl ,(λ 0 +Δλ 0 / 2)≦λ 2pr So that the wavelength λ 0 is the width Δλ 0 For a given wavelength interval [(λ 0 -Δλ 0 / 2),(λ 0 +Δλ 0 / 2)], where the reflection profile of the first reflective layer system (r 1s (λ),r 1p (λ)) and the reflection profile of the second reflective layer system (r 2s (λ),r 2p (λ)1sl , λ 1pl , λ 2sl , and λ 2pl denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance of at least 50% of the maximum reflectance, and λ 1sr , λ 1pr , λ 2sr , and λ 2pr denotes the longest wavelength at which s-polarized radiation and p-polarized radiation, respectively, are reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

[0025] JPEG2024533994000002.jpg27153

[0026] According to one embodiment, the wavelength interval [(λ 0 -Δλ 0 / 2),(λ 0 +Δλ 0 The degree of polarization of the first reflective layer system, defined as the ratio of reflectivities for s-polarized radiation and p-polarized radiation integrated over 1 / 2), is at least 1.5 times greater than the degree of polarization of the second reflective layer system.

[0027] JPEG2024533994000003.jpg22153

[0028] In embodiments of the invention, both the first and the second reflective component can be facet mirrors, in particular a pupil facet mirror with multiple pupil facets or a field facet mirror with multiple field facets. In yet other embodiments, both the first and the second reflective component can also comprise at least one mirror facet of a facet mirror, in particular a pupil facet mirror or a field facet mirror.

[0029] In yet another embodiment, both the first and second reflective components may be collector mirrors.

[0030] In yet other embodiments, both the first reflective component and the second reflective component may include at least one micromirror of a specular reflector.

[0031] According to one embodiment, the first and second reflective components are designed for an operating wavelength below 30 nm, in particular below 15 nm.

[0032] Further refinements of the invention can be taken from this description and the dependent claims.

[0033] The invention is explained in more detail below on the basis of exemplary embodiments shown in the attached drawings. [Brief description of the drawings]

[0034] [Figure 1a] FIG. 2 shows a diagram illustrating the different values ​​of reflectivity for s- and p-polarized light that can be obtained by changing the layer parameters of the reflective layer system. [Figure 1b] FIG. 2 shows a diagram illustrating the different values ​​of reflectivity for s- and p-polarized light that can be obtained by changing the layer parameters of the reflective layer system. [Figure 1c] FIG. 2 shows a diagram illustrating the different values ​​of reflectivity for s- and p-polarized light that can be obtained by changing the layer parameters of the reflective layer system. [Figure 1d] FIG. 2 shows a diagram illustrating the different values ​​of reflectivity for s- and p-polarized light that can be obtained by changing the layer parameters of the reflective layer system. [Diagram 2] 4 shows a typical wavelength-dependent profile of intensity corresponding to an exemplary transmission interval of an optical system. [Diagram 3] Figure 3a shows the wavelength-dependent profile of the reflectance of one reflective layer system for s-polarized and p-polarized light, respectively, and Figure 3b shows the wavelength-dependent profile of the reflectance of another reflective layer system for s-polarized and p-polarized light, respectively. [Figure 4]Figure 4a shows a wavelength-dependent profile of the reflectance of one reflective layer system over a larger wavelength range, with an exemplary transmission interval highlighted to illustrate the basic concepts of the present invention, and Figure 4b shows a wavelength-dependent profile of the reflectance of another reflective layer system over a larger wavelength range, with an exemplary transmission interval highlighted to illustrate the basic concepts of the present invention. [Diagram 5] FIG. 1 shows a diagram explaining the terms used within the present application. [Figure 6a] FIG. 13 shows layer thicknesses for an exemplary periodic layer system versus incident angle, depicting the layers with minimum and maximum rp for the full range of rs. [Figure 6b] FIG. 13 shows layer thicknesses for an exemplary periodic layer system versus incident angle, depicting the layers with minimum and maximum rp for the full range of rs. [Figure 6c] FIG. 13 shows layer thicknesses for an exemplary periodic layer system versus incident angle, depicting the layers with minimum and maximum rp for the full range of rs. [Figure 6d] FIG. 13 shows layer thicknesses for an exemplary periodic layer system versus incident angle, depicting the layers with minimum and maximum rp for the full range of rs. [Figure 6e] FIG. 13 shows layer thicknesses for an exemplary periodic layer system versus incident angle, depicting the layers with minimum and maximum rp for the full range of rs. [Figure 6f] FIG. 13 shows layer thicknesses of a periodic layer system for exemplary angles of incidence, based on layers with minimum and maximum rp for the full range of rs. [Figure 7]FIG. 7a shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7b shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7c shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7d shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7e shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7f shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7g shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. FIG. 7h shows a diagram of the area obtainable for an exemplary periodic or aperiodic stack in the rs-rp diagram as a function of the angle of incidence. [Figure 8] 1 shows a schematic and highly simplified view of a possible construction in principle of a lighting device; [Figure 9] 1 shows a schematic diagram illustrating an exemplary implementation of the invention in a pupil facet mirror; [Figure 10] 4 shows a schematic diagram illustrating a further possible realization of the invention in a segment of a pupil facet mirror; [Figure 11] 13 shows schematic diagrams illustrating further realization possibilities at the individual pupils of the pupil facet mirror; [Figure 12a] 3 shows a schematic diagram illustrating a further possible realization of the invention in a field facet mirror; [Figure 12b] 3 shows a schematic diagram illustrating a further possible realization of the invention in a field facet mirror; [Figure 13] 1 shows a schematic diagram of a basic possible structure of a projection exposure apparatus designed to work with EUV; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Common to the embodiments of the invention described below is the basic idea of ​​providing reflective optical components with different spectral reflection profiles such that for a given wavelength interval, one of the two components is suitable for a polarized mode of operation and the other of the two components is suitable for a non-polarized mode of operation, where said wavelength interval can be the transmission interval of the respective optical system (e.g. an illumination system of a microlithography projection exposure apparatus) for which the reflective optical component according to the invention is intended, which is typically determined by the reflection profiles of the remaining optical components in the optical system (e.g. optical components downstream with respect to the light beam path).

[0036] In the following, the principle underlying said targeted adjustment of each reflective layer system of a reflective optical component according to the invention for polarizing and non-polarizing operation respectively is first explained with reference to the diagrams in FIGS.

[0037] In principle, a given reflecting layer system for a given angle of incidence and a given wavelength spectrum of electromagnetic radiation will give a specific value r of reflectance for s-polarized radiation. s and a specific value r for the reflectance of p-polarized radiation p Thus, according to FIG. 1a, the reflective layer system includes r s -r p It can be represented on a diagram as a single point.

[0038] For a given material of each individual layer in the reflective layer system, r s and r p The value of also varies with each layer thickness, so that by changing these layer thicknesses, different value pairs (r s ,r p ) can be provided. As a result, it is possible to provide a reflective layer system having different value pairs (r s ,r p 1b, for example, by providing a plurality of corresponding reflective layer systems each having a r s -r p It is possible to cover a specific area of ​​the figure. s -r pThe specific design of this "obtainable area" in the figure can be further varied by changing the material combination of the individual layers in the reflective layer system, and for that purpose, FIG. 1c shows the r s -r p 4 shows exemplary further possible shapes of the obtainable area of ​​the diagram.

[0039] Thus, according to FIG. 1d, if in a plurality of provided reflective layer systems corresponding combinations of different materials of the individual layers are permitted or present, a corresponding combination of the associated accessible areas occurs.

[0040] In principle, therefore, after simulation of a multiple reflective layer system or a reflective optical component formed therewith, it is possible to obtain a uniquely defined layer structure according to the intended application or mode of operation. s -r p An appropriate selection of the defined points of the diagram can be made and the correspondingly manufactured reflective optical components can be exchanged as required. Again, depending on the usage scenario, this selection can alternatively be made in order to maximize the total reflectance provided by the reflective layer system or to provide a particular degree of polarization (corresponding to the ratio of reflectances obtained for s-polarized and p-polarized radiation, respectively).

[0041] In this connection, it should be noted that, for example, according to Figs. 1b to 1d, the practical or preferred value pair (r s ,r p ) are located at each edge of the obtainable region. Therefore, these situations are s -r p This can be attributed to the generally unfavorable nature of the points in the diagram, because the points or corresponding value pairs (r s ,r p ) is easily possible to find.

[0042] The reflective layer systems used according to the invention can be both periodic and aperiodic layer systems. In order to provide different spectral reflection profiles for both s-polarized and p-polarized radiation, the corresponding layer designs are appropriately modified so that each reflectance r s and r p The wavelength-dependent profile of finally has a shape suitable for polarized or unpolarized operation, respectively.

[0043] First, Fig. 2 shows the typical shape of the spectral radiant flux of an EUV radiation source. This curve is cut off outside the wavelength range that actually reaches the image plane or wafer plane in the optical system or illuminator when considering the respective spectral reflection profiles of the remaining optical components. The two cut-off wavelengths can only be approximately specified, since the spectral transmission profile of the optical system or illuminator usually only gradually approaches zero.

[0044] FIG. 5 shows a plot of the spectral reflectance profile r(λ), where the maximum reflectance r m is the wavelength λ m The shortest wavelength at which radiation is reflected with a reflectance of at least 50% of the maximum reflectance is called λ l The longest wavelength (r m / 2 reflectance) is r As shown in.

[0045] 3a and 3b show the respective wavelength dependence curves of reflectivity for s-polarized and p-polarized light for two exemplary reflective layer systems, in this example a non-periodic Mo-Si layer system. In this case, the relevant multilayer design shows the resulting reflectivity r for p-polarized radiation. p is selected from a number of simulated layer designs such that is minimum for the reflective layer system shown in Fig. 3a and is maximum for the reflective layer system shown in Fig. 3b. The qualitatively different curves of wavelength-dependent reflectance, which are easily discernible from a comparison of Fig. 3a and Fig. 3b, then become of practical relevance when considered over a relatively large wavelength range according to Fig. 4a and Fig. 4b, respectively.

[0046] As is evident from Figures 4a and 4b, the reflectivity peaks obtained for s-polarized light and p-polarized light, respectively, have different widths, and as expected, the peak in the wavelength-dependent profile of reflectivity for s-polarized light is wider than that for p-polarized light. Here, the reflectivity r p With these two "extreme" layer designs and by taking advantage of these circumstances, in the reflective layer system shown in FIG. 4b both peaks (i.e. for s-polarized and p-polarized light) are located within the transmission interval, whereas in the reflective layer system shown in FIG. 4a the maximum reflectance value for s-polarized light is located within the transmission interval but not for p-polarized light (rather according to FIG. 4a, for p-polarized light the downward slope of the corresponding peak in the reflectance curve is located within the transmission interval).

[0047] As a result, the reflective layer system shown in Fig. 4a has a substantially stronger polarizing effect on incident electromagnetic radiation than the one shown in Fig. 4b, in other words, the reflective layer system shown in Fig. 4a is suitable for an operation mode with polarized radiation, whereas the reflective layer system shown in Fig. 4b is suitable for an operation mode with unpolarized radiation.

[0048] The realization of the above-mentioned concept according to the invention in a reflective layer system in the form of an aperiodic multilayer system allows the two parameters of the width and position of each peak in the wavelength-dependent reflectance profile to be influenced independently of one another by changing the layer design. For a given layer design, the width and position of the peaks for s-polarized and p-polarized light cannot be selected completely independent of one another, since the values ​​corresponding to s-polarized and p-polarized light are correlated. However, as already explained on the basis of Figs. 4a and 4b, this is not necessary either. In contrast, when the invention is realized in a reflective layer system in the form of a periodic layer system with two given different layer materials ("bilayers") alternately arranged in a periodic manner, essentially only the position of the peak can be freely selected, and only a limited influence can be made on the width of the peak.

[0049] Tables 1 to 1 exemplarily show non-periodic layer designs for systems made of molybdenum silicon (MoSi) or ruthenium silicon (RuSi). sWhen fixed at r = 0.7, each table shows the maximum and minimum r p The layer design with each is shown.

[0050] For example angles of incidence, Figures 6a-h show the layer thicknesses of the periodic layer system, where the minimum and maximum r p A layer having r s In this case, the minimum and maximum r p A layer having r s 6a and 6d are respectively shown for the entire range of r p 6b and 6e show the respective individual layer thicknesses. p The long dashed line shows the thickness of silicon when the maximum r p The thickness of molybdenum or ruthenium in the case of is shown by a short dashed line. p The thickness of silicon in the case of the minimum r p The thickness of molybdenum or ruthenium in this case is represented by a dashed double-dashed line. Figures 6c and 6f show each period thickness, i.e. the sum of the two individual thicknesses (molybdenum and silicon or ruthenium and silicon).

[0051] Figures 7a to 7h show s -r p The range achievable for MoSi or RuSi with periodic or aperiodic stacks in the figure is shown as a function of the angle of incidence. The two interchangeable components do not necessarily correspond in material combination (MoSi or RuSi) and / or structure (periodic or aperiodic arrangement). Especially at angles sufficiently different from the Brewster angle of 0° and about 45°, r s -r p The range of choices available in the diagram is enormous.

[0052] [Table 1] (RuSi; angle of incidence 60°; r s =0.7;r p minimum The silicon layer of layer 1 is positioned directly on the substrate. The ruthenium layer of layer 50 forms the entrance surface for the EUV radiation. [Table 1-1] [Table 1-2]

[0053] [Table 2] (RuSi; angle of incidence 60°; r s =0.7;r p maximum The silicon layer of layer 1 is positioned directly on the substrate. The ruthenium layer of layer 50 forms the entrance surface for the EUV radiation. [Table 2-1] [Table 2-2]

[0054] [ 表3 ] (MoSi;入射角25°;rs =0.7;r p minimum The silicon layer of layer 1 is positioned directly on the substrate. The molybdenum layer of layer 50 forms the entrance surface for the EUV radiation. [Table 3-1] [Table 3-2]

[0055] [Table 4] (MoSi; angle of incidence 25°; rs=0.7; rp max. The silicon layer of layer 1 is positioned directly on the substrate. The molybdenum layer of layer 50 forms the entrance surface for the EUV radiation. [Table 4-1] [Table 4-2]

[0056] The concept according to the present invention of replacing at least one reflective component positioned in the light beam path with a component having a corresponding surface shape but a different reflective layer system in order to change the operating mode between "polarized" and "non-polarized" can in principle be realized for different components of an optical system or lighting device.

[0057] First, Fig. 8 shows a schematic and highly simplified view of a possible basic structure of an illumination device of a microlithography projection exposure apparatus designed to operate in the EUV wavelength range. In this case, EUV radiation generated by an EUV radiation source 802 (e.g. a plasma source) reaches, after reflection on a collector mirror 803, via an intermediate focus 801, a field facet mirror 810 having a number of independently adjustable field facets (e.g. for setting different illumination settings). From the field facet mirror 810, the EUV radiation is incident on a pupil facet mirror 820 and then on a reticle 830 located in the object plane of a projection lens (not shown in Fig. 8) arranged downstream in the optical beam path.

[0058] The invention is not limited to the structure of the illumination device shown in Fig. 8. Thus, in further embodiments, one or more further optical elements, for example in the form of one or more deflection mirrors, can also be arranged in the beam path.

[0059] A possible embodiment of the "component exchange" according to the invention will now be described with reference to the purely schematic illustrations of Figs.

[0060] Referring first to Figure 9, to effect a component exchange in accordance with the invention for the purpose of changing the mode of operation between "polarized" and "unpolarized", the pupil facet mirror (designated "920" in Figure 9) can be entirely replaced with another pupil facet mirror 920' (which, in accordance with concepts in accordance with the invention, has a different surface shape than pupil facet mirror 920 but not a different spectral reflectance profile or reflective layer system). This embodiment has the advantage that only a single component needs to be exchanged.

[0061] In yet another embodiment, shown in FIG. 10, it is also possible to replace individual segments of the pupil facet mirror 1020 (indicated as "1021" to "1024" in FIG. 10) with other segments (indicated as "1021'" to "1024'" in FIG. 10), each segment also comprising multiple pupil facets. This embodiment is advantageous in that it requires a relatively small number of elements to be realized as interchangeable. As shown in FIG. 11, in yet another embodiment, it is also possible to replace a single pupil facet (e.g. "1121" or "1122") of the pupil facet mirror 1120 with another pupil facet 1121' or 1122' (with the same surface shape but with a different design of the spectral reflectance profile or reflecting layer system, according to the concept according to the invention).

[0062] To the extent that reference has been made to pupil facet mirrors in the above embodiments, field facet mirrors can be realised in a similar manner.

[0063] 12a and 12b show, purely diagrammatically, yet another implementation option of the component exchange according to the invention. In this case, in an arrangement known per se from DE 10 200 13 136 A1, up to three field facet mirrors 1250, 1250', 1250'' can be arranged on an exchange device 1260 designed as a roller, the rotation of which allows a "switching" between said field facets 1250, 1250', 1250''. By tilting the axis of rotation, the respectively selected field facet 1250, 1250', 1250'' can be tilted so that the desired pupil facet of the pupil facet mirror is illuminated. In this case, according to the invention, the three field facets 1250, 1250', 1250'' located on a common roller are provided with different reflective layer systems.

[0064] 8, in yet another variant the reflective layer system can be attached to the collector mirror 803. An advantageous embodiment of the collector mirror for simplifying a highly precise exchange of the collector mirror is known from DE 10 2013 200 368 A1.

[0065] Fig. 13 shows a schematic diagram of an exemplary projection exposure apparatus designed to operate with EUV and in which the present invention can be implemented. According to Fig. 13, an illumination device 1380 of a projection exposure apparatus 1375 designed for EUV comprises a field facet mirror 1381 (with facets 1382) and a pupil facet mirror 1383 (with facets 1384). Light from a light source unit 1385 comprising a plasma source 1386 and a collector mirror 1387 is directed to the field facet mirror 1381. A first telescope mirror 1388 and a second telescope mirror 1389 are arranged in the optical path downstream of the pupil facet mirror 1383. A deflection mirror 1390 is arranged downstream in the optical path, which deflection mirror directs the incident radiation to an object field 1391 in an object plane OP of a projection lens 1395 comprising six mirrors M1 to M6. A reflective structure-bearing mask M is positioned at the location of the object field 1391, which is imaged onto an image plane IP using a projection lens 1395 (including six mirrors M1-M6).

[0066] Although the present invention has been described based on specific embodiments, multiple variations and alternative embodiments will become apparent to those skilled in the art, for example, by combining and / or substituting the features of the individual embodiments. Accordingly, as will be apparent to those skilled in the art, such variations and alternative embodiments are also encompassed by the present invention, and the scope of the present invention is limited only within the meaning of the appended claims and their equivalents.

Claims

1. A group of optical components, a first reflective component having a first reflective layer system; a second reflective component having a second reflective layer system; and the first reflective component and the second reflective component have optically effective surfaces corresponding to each other in shape; For a given wavelength interval and a given angle of incidence of incident electromagnetic radiation, the spectral reflectance profile (r １ｓ (λ), r １ｐ (λ)) is the corresponding spectral reflectance profile (r ２ｓ (λ), r ２ｐ (λ)), the spectral reflectance profile of the first reflective layer system represents the wavelength dependence of reflectivity for s-polarized and p-polarized radiation, The first reflective layer system is (l) ０ -No ０ / 2)≧λ １ｓｌ ,(l ０ +Dl ０ / 2)≦λ １ｓｒ and (l) ０ -No ０ / 2)≦λ １ｐｌ or (l ０ +Dl ０ / 2)≧λ １ｐｒ The wavelength λ ０ is the width Δλ ０ At a given wavelength interval [(λ ０ -Δλ ０ / 2), (λ ０ +Δλ ０ / 2)], wherein the reflection profile (r １ｓ (λ), r １ｐ (λ) １ｓｌ and λ １ｐｌ denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than 50% of the maximum reflectance, and λ １ｓｒ and λ １ｐｒ A family of optical components characterized by exhibiting the longest wavelengths at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

2. 2. The group of optical components according to claim 1, wherein the second reflective layer system satisfies the following conditions: (l) ０ -No ０ / 2)≧λ ２ｓｌ ,(l ０ +Dl ０ / 2)≦λ ２ｓｒ and (l) ０ -No ０ / 2)≧λ ２ｐｌ ,(l ０ +Dl ０ / 2)≦λ ２ｐｒ The wavelength λ ０ is the width Δλ ０ At a given wavelength interval [(λ ０ -Δλ ０ / 2), (λ ０ +Δλ ０ / 2)], wherein the reflection profile (r ２ｓ (λ), r ２ｐ (λ) ２ｓｌ and λ ２ｐｌ denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than 50% of the maximum reflectance, and λ ２ｓｒ and λ ２ｐｒ A family of optical components characterized by exhibiting the longest wavelengths at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

3. 2. The group of optical components according to claim 1, wherein the first reflective layer system satisfies the following conditions: (l) ０ -No ０ / 2)≧λ １ｓｌ ,(l ０ +Dl ０ / 2)≦λ １ｓｒ and (l) ０ -No ０ / 2)≦λ １ｐｌ or (l ０ +Dl ０ / 2)≧λ １ｐｒ and the second reflective layer system satisfies the following conditions: (l) ０ -No ０ / 2)≧λ ２ｓｌ ,(l ０ +Dl ０ / 2)≦λ ２ｓｒ and (l) ０ -No ０ / 2)≧λ ２ｐｌ ,(l ０ +Dl ０ / 2)≦λ ２ｐｒ The wavelength λ ０ is the width Δλ ０ At a given wavelength interval [(λ ０ -Δλ ０ / 2), (λ ０ +Δλ ０ / 2)], wherein the reflection profile (r １ｓ (λ), r １ｐ (λ)) and the reflection profile (r ２ｓ (λ), r ２ｐ (λ) １ｓｌ , λ １ｐｌ , λ ２ｓｌ , and λ ２ｐｌ denotes the shortest wavelength at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than 50% of the maximum reflectance, and λ １ｓｒ , λ １ｐｒ , λ ２ｓｒ , and λ ２ｐｒ A family of optical components characterized by exhibiting the longest wavelengths at which s-polarized radiation and p-polarized radiation are each reflected with a reflectance greater than or equal to 50% of the maximum reflectance.

4. 4. The optical component group according to claim 1, wherein the wavelength interval [(λ ０ -Δλ ０ / 2), (λ ０ +Δλ ０ a degree of polarization of the first reflective layer system, defined as the ratio of reflectivities for s-polarized radiation and p-polarized radiation integrated over [amount of reflection of the first reflective layer system relative to the polarization of the second reflective layer system], that is at least 1.5 times greater than the degree of polarization of the second reflective layer system.

5.

6. 4. The optical component group according to claim 1, wherein both the first reflective component and the second reflective component comprise at least one mirror facet of a faceted mirror (810).

7. An optical component group as described in claim 6, characterized in that both the first reflective component and the second reflective component include at least one mirror facet of a pupil facet mirror (820, 920, 1020, 1120) or a field facet mirror (810).

8. 4. The optical component group according to claim 1, wherein both the first reflective component and the second reflective component are faceted mirrors.

9. An optical component group as described in claim 8, characterized in that both the first reflective component and the second reflective component are pupil facet mirrors (820, 920, 1020, 1120) having multiple pupil facets or field facet mirrors (810) having multiple field facets.

10. The optical component group according to any one of claims 1 to 3, characterized in that both the first reflective component and the second reflective component are collector mirrors (803).

11. 4. The optical component group according to claim 1, wherein both the first reflective component and the second reflective component comprise specular reflector micromirrors.

12. 4. The optical component group according to claim 1, wherein the first and second reflective components are designed for an operating wavelength of less than 30 nm.

13. An optical component group as described in claim 12, characterized in that the first reflective component and the second reflective component are designed for an operating wavelength of less than 15 nm.

14. A group of optical components according to any one of claims 1 to 3, for use in an illumination device of a microlithography projection exposure apparatus.

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