WO2006131093A1

WO2006131093A1 - Method and device for reflection of radiation in the euv or x-ray wavelength range and method for producing a material having a refractive index sutiable therefor

Info

Publication number: WO2006131093A1
Application number: PCT/DE2006/000931
Authority: WO
Inventors: Hartmut Hillmer; Martin Rohrbach
Original assignee: Universität Kassel
Priority date: 2005-06-10
Filing date: 2006-05-30
Publication date: 2006-12-14
Also published as: DE102005027422A1

Abstract

A description is given of a method for reflection of radiation (5) in the EUV or X-ray wavelength range with the application of at least one reflective interface (3) a first material (2) having a first refractive index (n1) being provided on a side of the interface (3) that is intended for the incidence of the radiation (5) , and a second material (1) having a second refractive index (n2) being provided on that side of the interface (3) which is remote from the incident radiation (5), and a preselected angle (αi) of incidence being used for the incident radiation (5). According to the invention, in the case the wavelength range of the radiation (5) used, the first refractive index (n1) is greater than the second refractive index (n2). Moreover, for the radiation (5) an angle (αi) of incidence is chosen which is greater than 0 and is less than the angle (αc) of total reflection at most by an amount such that the total reflectivity at the interface (3) for the wavelength range chosen is greater than at an angle of incidence αI = 0°. In addition, a description is given of a method for producing a material which is particularly well suited to the method according to the invention, and a device suitable for EUV lithography and for the masking technique (Figure 1).

Description

Method and device for reflection of radiation in the EUV or X-ray wavelength range and method for producing a material with a suitable refractive index

The invention relates to methods and apparatus of the genera specified in the preambles of claims 1, 15 and 19.

Due to the need for further miniaturization of semiconductor devices, particularly integrated circuits, semiconductor technology faces challenges not previously known. Today, mass production of wafers for semiconductor chips is predominantly carried out with exposure machines which use electromagnetic radiation (UV light) in wavelength ranges around 248 nm and enable structures just below 100 nm. To even smaller structures such. B. to produce smaller gate lengths in field effect transistors, a jump to significantly shorter wavelength ranges for lithography must be completed for the next generation of chips. International committees have decided to develop lithographic processes for the EUV wavelength range (Extreme Ultra Violet or extremely soft X-ray light), ie for the wavelength range of approx. 10 nm to 14 nm, despite the difficulties and costs involved in the same order of magnitude (eg Lutz Aschke, Stefan Mengel, Jenspeter Rau in "Lithography on the Limit", c't 2003, Issue 13, pp. 198 to 207). A central role in the application of future EUV lithography processes is played by the exposure machines, also called steppers, and the masks used therein, in particular reflection masks, by means of which the patterns of integrated circuits or the like are imaged in a photoresist layer on a wafer. Since no lenses are available for radiation in the wavelength range from 10 nm to 14 nm, this image must be carried out according to the previous state of knowledge with reflective mirrors, built up in the manner of Bragg or DBR mirrors from layer stacks with up to one hundred thin layers are. However, there is the disadvantage that such mirrors reflectivity or reflectivities of a maximum of about 0.7 (= 70%) have. Is therefore z. B. a stepper with eleven or more mirrors needed, which should be the case in the rule, then results in a total reflectivity of only (0.7) ^π = 0.02 or 2%. As a result, just 2 watts from a 100 W radiation source arrive on the wafer, which is far from sufficient for economic applications.

Considerable efforts have therefore already been made to provide mirrors with higher reflectivities (eg DE 198 30 449 A1, US Pat. No. 6,229,652 Bl, US Pat. No. 6,228,512 Bl, US Pat. No. 6,449,086 Bl, DE 100 11 548 C2, DE 101 55 711 A1, DE 102 41 330 A1, DE 103 09 084 A1). However, none of these efforts has so far led to mirrors with reflectivities that even come close to 0.8 (= 80%) and therefore at eleven mirrors could at least lead to a total reflectivity of about 0.086 (8.6%). Therefore, in the future either higher exposure times per step and thus higher production costs per chip have to be accepted, or it must be attempted to create more powerful, especially for the EUV-suitable, strong plasma radiation sources.

Starting from this prior art, the technical problem of the present invention is generally to increase the reflectivity as noticeably as possible, in particular in the wavelength range of about 10 nm to 14 nm or even down to the X-ray range, in order thereby for the application of Method and Devices of the types described at the beginning to provide mirror reflectivities in the value range between 0 and 1, which approach as close as possible to 1. In this case, the increased reflectivities or the reflective components having them can be used independently of whether they are z. B. for mirrors, reflection or transmission masks in lithography or for other purposes.

To solve this problem, the characterizing features of claims 1, 15, 16 and 20 serve.

The invention is based on the recognition that the above-described problems are at least partly due to the fact that in the art tacitly assumed that the reflection at a reflective interface with an angle of incidence of about 0 ° must be possible (z. B. DE 102 41 330 Al), because even at angles of incidence of 10 ° or more such a steep drop in reflectivity occurs (eg, 101 55 711 Al) that larger angles of incidence must be avoided. In contrast, the invention proposes to exploit the possible total reflection in the transition from an optically denser medium into an optically thinner medium. Since the transition into an optically thinner medium, the exceeding of a critical angle has the consequence that entry into the thinner medium is no longer possible, at each total reflecting interface a reflectivity of one (= 100%) or at least almost reach one, so that a high radiation energy can be transmitted to the wafer even when using a plurality of mirrors. Apart from that, the invention provides the significant advantage that the mirrors of EUV lithography systems no longer have to consist of complicated layer bodies, since in principle even a single layer is sufficient for achieving the total reflection.

Further advantageous features of the invention will become apparent from the dependent claims.

The invention is described below with reference to the accompanying drawings and in Connection with exemplary embodiments explained in more detail. Show it:

Figure 1 is a schematic diagram of the inventive method for the reflection of radiation in the EUV wavelength range.

Fig. 2 to 6 different applications for the inventive method;

FIGS. 7 and 8 schematically show two preferred embodiments of an optical component according to the invention, which can be used in the method according to FIG. 1;

FIGS. 9 and 10 show the results of theoretical model calculations with respect to the total reflection of moldybdenum at a wavelength of 13.4 nm;

Fig. 11, 12 and 13, 14 the results of the Fig. 9 and 10 corresponding model calculations, but for ruthenium or rhodium;

FIG. 15 means for polarizing the radiation reflected according to the invention;

FIG. 16 schematically shows the general course of the refractive index and the extinction coefficient as a function of the frequency;

FIG. 17 schematically shows an enlarged detail from FIG. 16 for explaining a preferred production of an optical material which is particularly suitable for the purposes of the invention; and

Fig. 18 and 19 schematically each a lithography system, which is equipped with reflective components according to the invention.

Fig. 1 shows a reflective optical component in the form of a mirror with a layer 1, which is surrounded by a medium 2. The layer 1 and the medium 2 form, inter alia, an interface 3 which is flat here and intended for reflection of electromagnetic radiation in a wavelength range between 10 nm and 14 nm (EUV range). A radiation source 4 is provided on a side intended for the incidence of the radiation on the boundary surface 3, preferably a plasma light source which generates an incident beam 5 with a wavelength lying in the EUV range or a corresponding wavelength band. The beam 5 is reflected at the interface 3 and leaves it as a reflected beam 6. A normal 7 to the interface 3 forms with the incident beam 5 an angle of incidence Ce ₁ , the same reflection angle a _{ between the normal 7 and the reflected beam 6 results. The medium 2 is formed by a first material with a first refractive index% and lies on that side of the interface 3 on which the radiation source 4 and the incident light beam 5 are located. In contrast, the layer 1 is formed by a second material having a second refractive index n ₂ and arranged on the side facing away from the incident beam 5 side of the interface 3. In all of this, it is assumed that the first material (eg air, vacuum or a fluid) has a refractive index n _x _> _. 1, whereas the second material has a refractive index n ₂ <1.

Under these conditions, the beam 5 is totally reflected at an impact point 8 on the interface 3, provided that the angle of incidence a _x ≥ a _c , where a _{c is} the critical angle from which the total reflection begins. A consequence of the total reflection is that the intensity of the reflected beam 6 is practically the same as the intensity of the incident beam 5, since in total reflection, in principle, no refraction occurs in the optically thinner, second material of the layer 1.

Analogous conditions result in the embodiments according to Fig. 2 to 5, in which the same parts have the same, possibly additionally provided with a letter reference numerals. A difference to Fig. 1 is only that there are other geometric relationships. In Fig. 2 z. B. a curved interface 3a is provided. Fig. 3 shows two at an angle of 90 °. other standing, respectively planar boundary surfaces 3b and 3c. FIG. 4 shows three boundary surfaces 3d, 3e and 3f which adjoin one another at obtuse angles. Fig. 5 shows a cube corner with three at 90 ° adjacent boundary surfaces 3g, 3h and 3i. With reference to the radiation source 4, all interfaces 3 are formed as transitions from a material with U ₁ ≥ 1 into a material with n ₂ <1, ie as transitions from an optically denser to an optically thinner medium. In addition, the angles of incidence of the beams 5 impinging on these boundary surfaces 3 are each chosen such that total reflection results and, in addition, in FIGS. 3 and 5 the incident electromagnetic radiation is reflected in parallel. The points of impact of the beams 5 on the interfaces 3 are designated in FIGS. 2 to 5 by the reference numerals 8a to 8m.

Finally, FIG. 6 shows an exemplary embodiment in which, between the layer 1 and the surrounding medium 2, a boundary surface 3j which differs in a different way from FIG. 2 is present. This is designed such that incident beams 5 coming from the radiation source 4 are reflected at impact points 8n to 8s and then focused as reflected beams 6 all at a point 9. Again, all involved angles of incidence a _v to a ₅ above a critical angle a _c , which results from the material pairing used in the individual case or the refractive indices Ei ₁ and n ₂ and total reflection has the consequence.

The embodiment according to Fig. 7 differs from that of Fig. 1 in that the layer 1 is not formed as a comparatively thick disk, but as a very thin zone Ia applied to a carrier body or a carrier substrate 10 (eg., Silicon) is. This has the advantage that the circumstances under comparatively expensive material having a refractive index n ₂ <1 can be cost-saving applied as a thin film on a thick, solid support material and combined therewith to form a reflective optical component. Moreover, the embodiment of Fig. 7 is used in the same manner as described above for the embodiment of Fig. 1. The embodiment according to Fig. 8 corresponds to that according to Fig. 7 with the difference that on the thin layer Ia is still a transparent for the EUV wavelength range protective or cover layer 11 is applied, on the radiation source 4 side facing. In the layer 11 may be z. B. also act as an immersion liquid. This results in a component with three layers 10, Ia and 11. The cover layer 11 consists of a third material having a third refractive index n ₃ , which is preferably significantly greater than the refractive index n ₂ . As a result, the beam 5 incident at an angle of incidence β is refracted at an interface 12 between the cover layer 11 and the surrounding medium 2 relative to an incidence solder 14 before it strikes an interface 3k between the two layers 11 and 1a, which is shown in FIG however, for the sake of simplicity is not shown. According to the invention, the incident beam 5 in this case is preferably directed onto the boundary surface 12 at such an angle of incidence that a beam 15 penetrating the cover layer 11 in FIG. 8 strikes the boundary surface 3k at an angle of incidence which is equal to or greater than as the critical angle of total reflection. As a result, as in the case of FIGS. 1 to 7, it is achieved that the reflected beam 6 has practically the same intensity as the incident beam 5, provided that the cover layer 11 is adequately selected by suitable choice of the third material, ensuring that it reflects and possibly absorbs it Share is small. Theoretically, in this embodiment, the refractive index n _{3 could} also be smaller than the refractive index U ₁ and the angle of incidence β so chosen that it is smaller than the angle of total reflection at a point of impact on the boundary surface 12. For practical purposes are z. B. Materials for which n ₂ <U ₁ <n ₃ applies. In addition, the three layers Ia, 10 and 11 are suitably connected to a compact, designed as a multi-layer body component firmly together.

Incidentally, it is clear to those skilled in the art that the apparent from Fig. 7 and Fig. 8 layer structure can also be realized in the embodiments of Fig. 2 to 6. The first material used in all exemplary embodiments is preferably a material with n _t ≥ 1, in particular air with n «1, unless the use of a vacuum or a suitable fluid is preferred. For the second material are preferably materials such as molybdenum, ruthenium, rhodium or palladium, all of which have a refractive index n ₂ <1 in the wavelength range between 10 nm and 14 nm.

The advantages which can be achieved by the invention can be seen in particular from FIGS. 9, 10 and 11, 12 and 13 and 14. FIGS. 9, 11 and 13 show the dependencies of the reflectivity on the angle of incidence of the electrical radiation for the materials Molybdenum, ruthenium and rhodium in a linear scale, while the same dependencies are shown in Figs. 10, 12 and 14 with a logarithmic plot of reflectivity. In this case, a refractive index n << 0.9199 for molybdenum, n <0.8859 for ruthenium and n »0.8734 for rhodium are assumed, each at a wavelength of the incident radiation (beam 5 in FIG. 1) of λ = The absorption coefficients γ in the three cases at the specified wavelength γ are "61000 cm ^{" 1} for molybdenum, γ "168800 cm ^{" 1} for ruthenium and γ "300000 cm ^{" 1} for rhodium 14, the solid lines represent the reflectivities for a transverse electric wave TE and the dashed lines the reflectivity for a transverse magnetic wave TM of the electromagnetic radiation, and corresponding dependencies and advantages can be obtained with new materials described below with reference to FIGS Figs. 16 and 17 explained methods or otherwise tailor made.

As shown in FIGS. 9 and 10 for molybdenum, a comparatively low total reflectivity is present at an incident angle Oi ₁ = 0 °. With larger angles of incidence, the reflectivity of the TE wave steadily increases, while the reflectivity of the TM wave gradually drops to the so-called Brewster angle a _B. In the case of molybdenum, the Brewster angle, where the reflectivity for the TM wave is minimal and practically zero, is about 42.6 °. From this angle, the reflectivity of the TM wave increases steep and continuous, whereby it first at a point 16 in Fig. 10, which corresponds to an angle of incidence Ce ₁ »51.4 °, reaches the same value that it has at the angle of incidence Qi ₁ = 0 °. For the purposes of the present application, the angle at point 16 is referred to as angle a _G. If the angle of incidence «; increased even more, then the two TE and TM waves rise sharply until they reach the critical angle αj _j = a _c , occurs at the total reflection, as already explained with reference to Fig. 1. At the critical angle a _c and all larger angles of incidence a _{ until reaching the maximum possible angle of incidence a- _t = 90 °, the total reflection, here by an air / molybdenum interface 3 in conjunction with a radiation incident on the air side with the wavelength λ = 13.4μm is generated, practically 100%.

Corresponding conditions are shown in Fig. 11 and 12 for ruthenium and Fig. 13, 14 for rhodium. The only differences are the Brewster angles α _B , the angles a _G and the critical angles a _c , as can be seen from the following table:

For the purposes of the present invention, it is derived from FIGS. 9 to 14 that even at slightly smaller angles than the respective critical angle a _c , significantly higher reflectivities can be achieved than for the previously intended angle of incidence Ot ₁ 0 ° applies. In particular, at angles of incidence Ct ₁ > a _G , the total reflectivity, as shown in Fig. 9, 11 and 13, greater than the total reflectivity at a _{ = 0 °. However, Figs. 9, 11 and 13 also show that the total reflectivity decreases steeply at values for a- _v which are only slightly smaller than the critical angles a _λ = α _c . Therefore, only those angles of incidence are considered appropriate for the application of the method according to the invention, which are so little below a _c that the total reflectivity is well above 80%, such. B. Fig. 10 right from point 16 shows. This would be achieved if z. For example, eleven mirrors of the type described may be used in a stepper such that at least 8.5% (at 80% reflectivity per element) or 31.5% (at 90% reflectivity per element) of the existing radiant energy is present in the wafer which would be a significant step forward from the 2% previously thought possible. In addition, using angles of incidence between a _c and a _G , by using multilayer bodies having multiple total reflecting interfaces, reflectivities of nearly 100% may be achieved.

As the curves of Figs. 10, 12 and 14 further show, the reflectivity of the materials molybdenum, ruthenium and rhodium is at the critical angle o; _{c is} the total reflection, which is calculated from the given refractive indices, not exactly one, but slightly smaller. This is a consequence of the fact that the radiation penetrates slightly into the material despite total reflection and therefore the absorption at the critical angle a _{c is} not zero. However, calculations show that at an angle of incidence j j of the beam 5 (Fig. 1), which is slightly larger than the critical angle a _c , the proportion attributable to absorption of the radiation decreases very rapidly. If the angle of incidence z. B. a _λ = a _c + 0.1 °, then the intensity of the radiation in the layer 2 (Fig. 1), starting from the interface 3, at a depth of 200 nm already to 1% and at a depth of 500 nm already dropped to 1% o of the radiation occurring. Even more favorable conditions arise at even greater angles of incidence. This means that in total reflection, the penetration depth of the radiation into the layer 1 (Fig. 1) is extremely small and therefore the proportion attributable to the absorption can be largely neglected, even if the extinction factor γ as shown in Fig. 9 to 14 is considerable. The low penetration depth thus prevents the emergence of a remarkable absorption, so to speak.

A resulting, further advantage of the invention is that the thickness of the layer 1 can be chosen comparatively small. It only has to be so large that the total reflection, which is physically a surface effect, can take place. Layer thicknesses of at least 30 nm are hitherto regarded as completely sufficient. For this reason too, the exemplary embodiment according to FIG. 7 is considered best at present, according to which the layer 1a is formed only as a thin film on a carrier substrate 10. Apart from that, an absorption of the order of 1% or 2% would still lead to a reflectivity of about 98%, which means a huge jump compared to the previously possible 70%.

FIG. 15 shows schematically a highly reflecting surface of a layer 1 according to the invention adjacent to an interface 3 according to FIG. 1. In this surface, elements 17 in the form of ribs, lines, lines, trenches or the like are formed with the target, the reflected one Beam 6 (Figure 1) to be polarized in a preselected manner. These elements 17 suitably have dimensions which are smaller than the wavelengths or wavelength ranges used and can also be produced by nanotechnological self-organization. On the total reflectivity of the interface 3, the elements 17 have no influence. A certain degree of polarization could also be obtained by using a plurality of interfaces of the type described one behind the other.

Fig. 16 shows schematically and in general form the course of the refractive indices (refractive indices) and the extinction coefficients of a solid layer as a function of the frequency, for. As for the material silicon or molybdenum. It can be seen that it can be recycled at frequencies f _x and f ₄ comes to absorption maxima due to resonances which od at the molecular, ionic, atomic or electron oscillations. Like.. The largest frequency f _j caused by an electron oscillator is particular to the purposes of the invention significant because it corresponds to wavelengths in the described EUV range and can lead to refractive indices of n <1. Are strikingly in fig. 16 also the great variations in the refractive indices, wherein the turning points of the n-curve at the frequencies f] to f ₄ are. In Fig. 17 is shown with a solid line 18, the course of the refractive index n greatly enlarged. It is assumed for the illustrated example that there is a comparatively broad frequency band f _UG to f _0G above the frequency fj, which is shown in FIG. 17 with a thick line 19 and leads to refractive indices which are significantly less than 1. For the purposes of the invention, this frequency band f _UG to f _{0G would} therefore be particularly well suited. A less suitable material for the same frequency band is shown in Fig. 17 with a dashed line 20.

Corresponding considerations also apply to layers Ia produced from a liquid film in FIGS. 7 and 8. Furthermore, in the future a nanosystem technology actuation of components of an array for the reduction of the refractive index in a range far below one is conceivable.

With regard to the technical application of the method according to the invention which makes use of the total reflection, for example in a stepper, it may be desirable to provide materials with the smallest possible critical angles a _{c of} the total reflection. According to the invention, it is therefore further proposed to provide materials known _{per se} by material science, chemical and physical methods having a refractive index which is significantly less than unity in a frequency band f _UG to f _0G , in particular in the wavelength range of 10 nm to 14 nm of interest here is. That could be z. B. be achieved in that in a material in which the highest frequency fj is in the averted EUV range, the associated oscillator is attenuated. In this case, the material would be suitable for existing EUV lithography equipment. Another possibility would be to use a material that is in a different wavelength range, for. B. in the X-ray region or z. B. 7 nm according to Fig. 16 and 17 is formed, ie correspondingly low refractive indices | n | <1 or | n | <4 1, and the lithography To set up a new facility for this new wavelength, if this results in better results than in the EUV area.

In both cases, by suitable material design and / or shift the frequency band to be used (eg. B. _UG f to f _OG close to f _x zoom in Fig. 17) tailored completely new materials and. Suitable for this purpose are numerous procedures, which include the alloying includes, in the well-known materials such. As molybdenum can be applied. Physically and chemically, this requires the chemical nature, the atoms or molecules (eg the masses) used in the layer, the bonding conditions (effective masses of all electrons and corresponding "spring constants") or the technological production parameters (eg optimization of the Pressure, sputtering angle, temperature, deposition rate or the like in making an alloy). In this case, it is achieved by the design of the material that results in the smallest possible refractive index in the selected frequency band and therefore a comparatively small critical angle a _{c of} the total reflection is obtained. Since, however, according to Fig. 16, a large absorption occurs in the region of f _x , the design must also aim at achieving the smallest possible absorption, theoretical model calculations may help, such. B. in Fig. 9 to 14 is shown.

Method for design of novel materials with significantly smaller refractive indexes than those known to date, in addition to the alloying with various elements, the displacement of the frequency band f _UG - f _0G and explained above, the optimized production methods also completely novel manufacturing processes, and the tailoring of novel classes of materials include. In this case, the smallest possible wavelengths in the EUV or X-ray range should again preferably be striven for as small a refractive index as possible in order to obtain comparatively small critical angles of total reflection, which would be expedient for many practical applications. A concrete method for producing such a material may, for. Example, in that first a material is selected, which has a resonant frequency f _y in the vicinity of the selected wavelength range. Subsequently, z. For example, the material properties are modified by alloying, wherein by stepwise changing certain parameters, the refractive index in a selected wavelength range (eg, f _UG to f _0G ) to a value as far as possible below 1 of z. B. to bring 0.5 <n <l. To reduce the influence of the spectral absorption measures can also be taken to the leading to the frequency f _t oscillator, z. B. an electrical binding state, to de-steam. In this way, ultimately, a material or a combination of materials can be found that meets the requirements. As starting materials for this molybdenum, ruthenium, rhodium and palladium are currently considered to be most suitable.

The invention is suitable, inter alia, for use in lithographic systems (steppers). Systems of this kind are known per se from DE 198 30 449 A1, DE 102 41 330 A1 and DE 103 09 084 A1, which are hereby incorporated by reference into the subject of the present application. A typical lithographic exposure apparatus of this type is shown schematically in FIGS. 18 and 19, according to which an electromagnetic radiation coming from a radiation source 21 is directed onto a wafer 23 by means of a plurality of mirrors 22, 22a. On this is a photoresist layer 24, on which a radiation path located in the mask 25 is usually shown reduced in size, which in Fig. 18 is a transmission and in Fig. 19 is a reflection mask. To simplify the illustration, only four of the generally at least ten mirrors 22, 22a are shown here. According to the invention, all mirrors 22, 22a corresponding to the components described above are provided with totally reflecting layers 1, 1a, and the angles of incidence are at all mirrors 22, 22a or their z. B. in the sense of Fig. 1 to 8 formed interfaces 3 and 3a to 3k chosen so that total reflection results. As a result, it is achieved that virtually 100% of the energy emitted by the radiation source 21 and not only the previously considered feasible about 2% thereof (at eleven mirrors 22) reach the wafer 23.

It is particularly expedient to also form the mask 25 according to FIGS. 18 and 19 in the manner described. For reflection and transmission masks, the greatest possible contrast between transparent and reflective mask parts 26 and 27 is desired. If the reflective mask parts 27 are formed in accordance with FIG. 1 and the rays coming from the radiation source 21 or from the last mirror 22a are directed at these mask parts 27 at an angle of incidence which is greater than the angle a _G according to FIGS. 9 to 14 Optimum reflectivity of the mask parts 27 is also ensured. If the angle of incidence is ex; > a _c , then total reflection occurs with the result that the mask parts 27 are practically opaque to the EUV rays.

The invention is not limited to the described embodiments, which can be modified in many ways. This applies in particular to the materials exemplified and the components produced with them. The wavelength range of 10 nm to 14 nm lying in the EUV range is also only an example, since other wavelength ranges can be achieved or adjusted if the features according to the invention are analogously modified. Furthermore, it is clear that instead of air or vacuum for the medium 2, other materials, in particular different fluids come into consideration. It would also be possible to provide other than the in Fig. 1 to 6 exemplified, geometric beam paths. Finally, it is understood that the various features may be applied in combinations other than those described and illustrated.

Claims

claims

1. A method for the reflection of radiation in the EUV or X-ray wavelength range using at least one reflective interface (3, 3a to 3k), by determining on a side of the interface (3, 3a to 3f) intended for the incidence of the radiation (5) 3k) a first material having a first refractive index (n _x ) and on the side facing away from the incident radiation of the interface (3, 3a to 3k) a second material having a second refractive index (n ₂ ) and for the incident radiation (5 ) a preselected angle of incidence (a) is used, characterized in that the materials are chosen such that for the wavelength range of the radiation (5) used the first refractive index (Xi ₁ ) is greater than the second refractive index (n ₂ ) and for the radiation (5) an angle of incidence (a) is selected which is greater than 0 and at most is so much smaller than the critical angle (α _c) of the total reflection that the Gesamtreflektivit t is greater than at the boundary surface (3, 3a to 3k) at an incident angle of (X ₁ = 0 °.

2. The method according to claim 1, characterized in that an angle of incidence Qj _{1 is} selected which is greater than an angle α _G > α _B , where α _{B is} the Brewster angle and a _{G is} an angle at which the reflectivity of the transverse magnetic wave (TM) of the radiation (5) is at least as large as at a .Einfallswinkel «i = 0 °.

3. The method according to claim 1 or 2, characterized in that as the angle of incidence (a) of the radiation (5) an angle is selected which is greater than the critical angle (a _c ) of the total reflection.

4. The method according to any one of claims 1 to 3, characterized in that as the first material air, vacuum or a fluid is used.

5. The method according to any one of claims 1 to 3, characterized in that as first material is a material with U ₁ > 1 is used.

6. The method according to claim 5, characterized in that as the first material, an immersion liquid is used.

7. The method according to any one of claims 1 to 6, characterized in that an optical component is used which has a carrier substrate (10) on which a thin layer (Ia) of the second material is applied.

8. The method according to any one of claims 1 to 7, characterized in that an optical component is used, on the side facing away from the incident radiation (5) side of the interface (3, 3a to 3k) a layer of the second material and on the side facing the incident radiation (5) has a cover layer (11) of a third material having a third refractive index (n ₃ ) which is greater than the second refractive index (n ₂ ).

9. Method according to claim 8, characterized in that n ₂ <U ₁ <n ₃ applies to the third refractive index (n ₃ ).

10. The method according to any one of claims 1 to 9, characterized in that the incident radiation (5) with a arranged in air or vacuum and the radiation (5) directed to the first or third material radiation source (4) is generated.

11. The method according to any one of claims 1 to 10, characterized in that a material selected from the group consisting of molybdenum, ruthenium, rhodium and palladium as the second material.

12. The method according to any one of claims 1 to 11, characterized in that a multi-layer body is used which contains a plurality of, according to one or more of claims 1 to 11 formed interfaces (3, 3a to 3k).

13. The method according to any one of claims 1 to 12, characterized in that a polarization of the reflected radiation (6) is provided by the fact that in the reflective interface (3, 3a to 3k) by nanotechnology self-organization an aligned arrangement of elements (17) from the group ribs, lines, lines or ditches is attached.

14. The method according to claim 13, characterized in that the polarization of the radiation by use of a plurality of interfaces (3, 3a to 3k) is obtained according to one of claims 1 to 13.

15. A method for producing a material having a refractive index n <1 with respect to electromagnetic radiation in the EUV wavelength range, characterized in that a material is selected which, at least in the vicinity of a the EUV or X-ray wavelength range of the radiation associated frequency band has a resonant frequency (Y ₁ ), and that with the help of materials science methods the refractive index | n | for this resonance frequency (f _x ) of the inequality | n | <1, preferably | n | <ξ 1 is enough.

16. A method for producing a material having a refractive index n <1 to electromagnetic radiation in the EUV or X-ray wavelength range, characterized in that materials are created by material design, in particular by varying the production parameters and / or the material composition, at least in the Near a frequency band associated with the selected EUV or X-ray wavelength range of the radiation have a resonant frequency Cf ₁ ), and that among these materials is selected that material which at the resonant frequency (f _{ ) has a refractive index | n | that of the inequality | n | <1, preferably | n | <1 is enough.

17. The method according to claim 15 or 16, characterized in that the refractive index | n | is brought to a smaller value, that the

Resonant frequency Cf ₁ ) associated oscillator is attenuated.

18. The method according to any one of claims 15 to 17, characterized in that the material is prepared on the basis of a material from the group molybdenum, ruthenium, rhodium and palladium.

19. The method according to any one of claims 15 to 18, characterized in that from the material in the EUV or X-ray wavelength range reflective optical component is prepared by the material is applied as a thin layer on a solid support substrate (10).

20. An apparatus for reflecting radiation in the EUV or X-ray wavelength range with at least one reflective component (22, 22a, 25), in particular for lithography, characterized in that the component (22, 22a, 25) has at least one reflective interface ( 3, 3a to 3k) according to one or more of claims 1 to 14 and the radiation (5) is directed at an angle of incidence on the reflecting interface (3, 3a to 3k), which is greater than 0 and at most by less than the angle (ct _c ) of the total reflection is that the total reflectivity at the interface (3, 3a to 3k) is greater than at an angle of incidence of (X ₁ = 0 °.

21. The device according to claim 20, characterized in that it comprises a plurality of components (22, 22a, 25) with reflective boundary layers (3, 3a to 3k), wherein the radiation (5) at all interfaces (3, 3a to 3k ) is subjected to total reflection.

22. The device according to claim 20 or 21, characterized in that the reflective components (22, 22a, 25) each have a solid carrier substrate (10) which is provided with a thin, the interface (3, 3a to 3k) forming surface layer ,

23. Device according to one of claims 20 to 22, characterized in that at least one component (22, 22 a, 25) is a mirror or a mask.