EUV collector for use in an EUV projection exposure system

Abstract

The invention relates to an EUV collector (24) for use in an EUV projection exposure system. The EUV collector (24) is designed to guide useful EUV light (3) from a source region (19) to a collecting region (26). The EUV collector (24) has at least one reflection surface region (28) which has the shape of a section of an ellipsoid with two ellipsoid focal points (F1, F2). The source region (19) is arranged in the region of one of the ellipsoid focal points (F1) and the collecting region (26) is arranged in the region of the other of the ellipsoid focal points (F2). For useful light beam paths emanating from the source region (19), the reflection surface region (28) has a maximum collection angle Ω of at least 90°. Alternatively or additionally, the reflection surface region (28) has at least two reflection surface partial regions which are detachably connected to one another and each represent partial regions of a shape of a section of an ellipsoid having two ellipsoid focal points (F1, F2).

Description

[0001] EUV collector for use in an EUV projection exposure system

[0002] The content of the German patent application DE 102024210928.2 is incorporated herein by reference.

[0003] The invention relates to an EUV collector for use in an EUV projection exposure system. Furthermore, the invention relates to an illumination system with such a collector, an optical system with such an illumination system, a projection exposure system with such an optical system, a manufacturing method for producing a micro- or nano-structured component, and a micro- or nano-structured component produced by this method.

[0004] An EUV collector of the type mentioned above is known from US 9,754,695 B2, WO 2011 / 138259 A1, WO 2024 / 132708 A1, and DE 102019200698 A1. US 2007 / 0114468 discloses a collector for an EUV light source. DE 102013218132A1 discloses a collector for transferring EUV illumination light from a radiation source area to an illumination optic. DE 102022203745 A1 discloses an EUV collector for an EUV projection exposure system. DE 102010039965 A1 discloses an EUV collector for an EUV projection exposure system.

[0005] It is an object of the present invention to further develop an EUV collector of the type submitted in such a way that its useful light throughput is improved.

[0006] This problem is solved according to the invention by an EUV collector with the features specified in claim 1. According to the invention, it was discovered that with an EUV collector having at least one ellipsoidal reflective surface area, it is possible to select arrangements and designs of the ellipsoidal basic shape of the reflective surface area that result in a large maximum collecting angle compared to the prior art. A correspondingly advantageous and high useful light throughput is the consequence. Surprisingly, it has been found that the requirements associated with such a design of the EUV collector, namely that a source-side ellipsoidal focal point lies relatively close to the reflective surface area, are manageable. The useful light collecting angle is defined in a meridional plane of the EUV collector between an optical axis of the collector and the respective useful light beam emanating from the source area.The optical axis of the collector and its reflective surface area is a connecting line between the two ellipsoidal focal points of the ellipsoidal shape of the reflective surface area. The maximum collecting angle of the reflective surface area can be greater than 90°, at least 95°, at least 100°, at least 105°, at least 110°, at least 115°, at least 120°, at least 125°, at least 130°, at least 135°, at least 140°, at least 145°, at least 150°, at least 155°, at least 160°, at least 165°, and at least 170°. This collecting angle is typically less than 178°. For stray light diffraction, at least one reflective surface area of ​​the EUV collector can have at least one diffraction structure.For the design of corresponding diffraction structures, reference is made in particular to DE 102019200698 Al. The base body of the EUV collector can be made of a material with particularly high thermal stability and / or particularly high thermal conductivity. Examples of such materials are SiSiC or aluminum. Alternative materials for this base body are copper, alloys containing copper and / or aluminum, or powder metallurgy alloys of copper and aluminum oxide.Alternatively or additionally possible materials for the base body of the EUV collector, which are characterized by high thermal stability and thermal conductivity, are reflective materials such as molybdenum, tantalum, nickel, ceramic materials such as aluminum oxide, aluminum silicate, zirconium oxide, silicon carbide, aluminum nitride, beryllium oxide, metal alloys such as copper-molybdenum, copper-chromium-zirconium, nickel-chromium, iron-nickel-chromium, non-metallic materials such as graphite, quartz glass and transition metals such as tungsten.

[0007] Particularly good useful light throughput results in an embodiment of the EUV collector according to claim 2, where the large maximum collecting angle is present for all planes containing the optical axis.

[0008] An EUV collector according to claim 3 has manufacturing advantages.

[0009] Passage openings according to claims 4 to 6 have proven to be advantageous in the use of the EUV collector, in particular with a plasma generator, which is described for example in DE 102019200698 Al.

[0010] An embodiment of the EUV collector according to claim 7 enables precise guidance of the EUV useful light. A cooling device according to claim 8 can prevent thermal overload of the reflective surface area. The cooling device can be designed as an active and / or passive cooling device. The cooling device can be designed to guide a cooling medium, in particular through a base body of the EUV collector. Such a cooling medium can be circulated in a cooling medium circuit.

[0011] The aforementioned problem is also solved by an EUV collector with the features specified in claim 9.

[0012] In this design, an ellipsoidal basic shape of the reflection surface area is complemented by two detachably connected reflection surface sub-areas. These sub-areas can then be exchanged independently of each other, for example, if this is necessary for degradation purposes.

[0013] Details discussed above in connection with the EUV collector according to claims 1 to 8 may also be present in the EUV collector according to claim 9.

[0014] The EUV collector according to claim 9 may in turn have through-openings according to claims 4 to 7. A cooling device may also be present in the EUV collector according to claim 9.

[0015] The advantages of a large collecting angle according to claim 10 correspond to those already explained above in connection with the EUV collector according to claim 1. An interchangeable module design according to claim 11 facilitates the replacement of the reflective surface sub-area whose reflective surface is closest to the source area focal points. At least one further reflective surface sub-area can then be designed to remain in place, i.e., be stationary, such that, after the exchange of the replaceable reflective surface sub-area via the collector interchangeable module, it again complements this replaced reflective surface sub-area to form the complete EUV collector with an ellipsoidal reflective surface basic shape. With such a design, through-openings can be present in the replaceable reflective surface sub-area and / or in the stationary reflective surface sub-area. Active cooling can be implemented, in particular, in the replaceable reflective surface sub-area.

[0016] The advantages of a lighting system according to claim 12 correspond to those already explained above with reference to the EUV collector according to the invention.

[0017] The lighting system can be designed to remove stray light at designated stray light removal points, such as beam dumps. Alternatively or additionally, the distribution of the useful light, particularly in specific sections of the lighting system's beam path, for example in the area of ​​the pupil plane, can be ensured by using collector sections with different diffraction or reflection properties.

[0018] The advantages of an optical system according to claim 13, a projection exposure system according to claim 14, a manufacturing method according to claim 15 and a micro- or nano-structured component according to claim 16 correspond to those already explained above with reference to the collector according to the invention.

[0019] The projection exposure system can be used to manufacture, in particular, a semiconductor component, for example a memory chip.

[0020] Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. This drawing shows:

[0021] Fig. 1 schematically shows a projection exposure system for EUV microlithography;

[0022] Fig. 2 Details of a light source of the projection exposure system in the vicinity of an EUV collector with a large useful light collecting angle for guiding EUV useful light from a plasma source area to a field facet mirror of an illumination optic of the projection exposure system, wherein the EUV collector is shown in a medial section;

[0023] Fig. 3 shows a meridional section through a reflective surface of an embodiment of the EUV collector with a large useful light collecting angle, with some parameters for describing an ellipsoidal shape of the reflective surface highlighted, wherein the EUV collector can be used in the projection exposure system according to Fig. 1; Fig. 4 shows, in a representation similar to Fig. 3, another embodiment of an EUV collector with a large useful light collecting angle, which is enlarged again compared to the embodiment according to Fig. 3;

[0024] Fig. 5 Main components for guiding EUV useful light from a source area of ​​an EUV light source to an illumination optic of the projection exposure system, wherein a further embodiment of an EUV collector with a large useful light collecting angle with two detachably connected reflective surface sub-areas is shown, each representing sub-areas of an ellipsoidal segment; and

[0025] Fig. 6. in a representation similar to Fig. 5, main components of a guide for the EUV useful light using a further embodiment of an EUV collector with two detachably connected reflective surface sub-areas, wherein, in comparison to Fig. 6, the EUV collector has a larger useful light collecting angle.

[0026] A projection exposure system 1 for microlithography has a light source 2 for illumination light or imaging light 3, which will be explained in more detail below. The light source 2 is an EUV light source that generates light in a wavelength range, for example, between 5 nm and 30 nm, and in particular between 5 nm and 15 nm. The illumination or imaging light 3 is also referred to below as EUV working light. The light source 2 can, in particular, be a light source with a wavelength of 13.5 nm or a light source with a wavelength of 6.9 nm. Other EUV wavelengths are also possible. A beam path of the illumination light 3 is shown in a highly schematic way in Fig. 1.If EUV useful light with a wavelength of 13.5 nm is to be used within the projection exposure system 1, for example a wavelength component in the range of 6.9 nm is an out-of-band false light wavelength component.

[0027] To guide the illumination light 3 from the light source 2 to an object field 4 in an object plane 5, an illumination optic 6 is used. The latter comprises, as illumination optic mirrors, a field facet mirror FF (shown highly schematically in Fig. 1) and a pupil facet mirror PF (also shown highly schematically) located downstream in the beam path of the illumination light 3. Between the pupil facet mirror PF, which is arranged in a pupil plane 6a of the illumination optic, and the object field 4, a field-shaping mirror 6b for grazing incidence (Gl mirror, grazing incidence mirror) is arranged in the beam path of the illumination light 3. Such a Gl mirror 6b is not strictly necessary.

[0028] The pupil facets of the pupil facet mirror PF (not shown in detail) are part of a transmission optic that superimposes the field facets of the field facet mirror FF (also not shown) onto the object field 4 and, in particular, images them. A previously known embodiment can be used for the field facet mirror FF on the one hand and the pupil facet mirror PF on the other. Such an illumination optic is known, for example, from the

[0029] DE 102009045 096 AL With a projection optic or imaging optic 7, the object field 4 is mapped onto an image field 8 in an image plane 9 with a predetermined reduction scale. Projection optics suitable for this purpose are known, for example, from DE 102012202675 AL.

[0030] To facilitate the description of the projection exposure system 1, a Cartesian xyz coordinate system is shown in the drawing, from which the respective positional relationships of the components depicted in the figures can be derived. In Fig. 1, the x-direction runs perpendicular to the drawing plane and into it. The y-direction runs to the left in Fig. 1, and the z-direction runs upwards in Fig. 1. The object plane 5 runs parallel to the xy-plane.

[0031] Object field 4 and image field 8 are rectangular. Alternatively, object field 4 and image field 8 can also be curved, specifically partially ring-shaped. Object field 4 and image field 8 have an xy aspect ratio greater than 1. This means that object field 4 has a longer object field dimension in the x-direction and a shorter object field dimension in the y-direction. These object field dimensions run along the field coordinates x and y.

[0032] For the projection optics 7, one of the embodiments known from the prior art can be used. Here, a section of a lithography mask in the form of a reflection mask 10, also referred to as a reticle, is imaged, coinciding with the object field 4. The reticle 10 is supported by a reticle holder 10a. The reticle holder 10a is moved by a reticle displacement drive 10b. The image by the projection optics 7 is projected onto the surface of a substrate 11 in the form of a wafer, which is supported by a substrate holder 12. The substrate holder 12 is moved by a wafer or substrate displacement drive 12a.

[0033] Figure 1 schematically shows a beam 13 of the illumination light 3 entering the projection optic 7 between the reticle 10 and the projection optic 7, and a beam 14 of the illumination light 3 exiting the projection optic 7 between the projection optic 7 and the substrate 11. The image-side numerical aperture (NA) of the projection optic 7 is not shown to scale in Figure 1.

[0034] Projection exposure system 1 is of the scanner type. Both the reticulum 10 and the substrate 11 are scanned in the y-direction during operation of projection exposure system 1. A stepper type of projection exposure system 1 is also possible, in which the reticulum 10 and the substrate 11 are moved stepwise in the y-direction between individual exposures of the substrate 11. These movements are synchronized with each other by appropriate control of the movement drives 10b and 12a.

[0035] Fig. 2 shows details of the light source 2 and a subsequent guide for the EUV utility light 3.

[0036] Light source 2 is an LPP source (laser-produced plasma). To generate the plasma, tin droplets 15 are produced as a continuous droplet sequence by a tin droplet generator 16, which is part of light source 2. The tin droplets 15 constitute a plasma medium of the plasma source. The trajectory of the tin droplets 15 is perpendicular to a main beam direction 17 of the EUV useful light 3. The tin droplets 15 travel freely between the tin droplet generator 16 and a tin collector 18, passing through a plasma source region 19. The EUV useful light 3 is emitted from the plasma source region 19. Within the plasma source region 19, the arriving tin droplet 15 is stimulated by pump light 20 from a pump light source 21. The pump light source 21 can be an infrared laser source in the form of, for example, a CCE laser.Another IR laser source is also possible for the pump light or pump radiation, in particular a solid-state laser, for example an Nd:YAG laser.

[0037] The pump light 20 can have an IR wavelength in the range between 10.1 pm and 10.7 pm. Depending on the design of the pump light source 21, the pump light 20 can alternatively or additionally also have a wavelength in the range of 1 pm, for example, 1.064 pm.

[0038] It is also possible to use a different pump light wavelength, which then represents a false light wavelength, in the IR, NIR, VIS, UV or DUV wavelength range.

[0039] In addition to the EUV useful light 3, the plasma source area 19 also emits other, undesired stray light wavelength components in the form of stray light radiation. This stray light radiation has a stray light wavelength that differs from the useful light wavelength of the EUV useful light 3 by at least 10%. The stray light wavelength can be the pump light 20. Alternatively or additionally, the stray light wavelength can be an EUV wavelength, a DU V wavelength, a UV wavelength, a VIS wavelength, a NIR wavelength, or an out-of-band EUV wavelength.

[0040] The pump light 20 is directed into the plasma source area 19 via a mirror 22, which can be a controllably tiltable mirror, and a focusing lens 23. The pump light causes the tin droplet 15 arriving in the plasma source area 19 to be transformed into a plasma emitting the EUV useful light 3. A beam path of the EUV useful light 3 between the plasma source area 19 and the field facet mirror FF is shown in Fig. 2, insofar as the EUV useful light is reflected by a collector mirror 24, which is hereinafter also referred to as the EUV collector 24. The EUV collector 24 has a central aperture 25 for the pump light 20, which is focused via the focusing lens 23 towards the plasma source area 19.The collector 24 is designed as an ellipsoidal mirror and transfers the EUV useful light 3 emitted by the plasma source area 19, which is arranged at one ellipsoidal focal point, to an intermediate focus 26 of the EUV useful light 3, which is arranged at the other ellipsoidal focal point of the collector 24. The intermediate focus 26 is also referred to as the collecting area for the EUV useful light 3.

[0041] Exemplary embodiments of the EUV collector 24, which has a large collecting angle for the EUV useful light 3, are explained below in connection with Figures 3 ff.

[0042] The base body of the EUV collector 24 can be made of SiSiC or aluminum. Alternative materials for this base body include copper, alloys containing copper and / or aluminum, or powder metallurgy alloys of copper and aluminum oxide. Other possible materials for the base body of the EUV collector 24, characterized by high thermal stability and thermal conductivity, include reflective materials such as molybdenum, tantalum, and nickel; ceramic materials such as aluminum oxide, aluminum silicate, zirconium oxide, silicon carbide, aluminum nitride, and beryllium oxide; metal alloys such as copper-molybdenum, copper-chromium-zirconium, nickel-chromium, and iron-nickel-chromium; non-metallic materials such as graphite and quartz glass; and transition metals such as tungsten.

[0043] In addition to the through-hole 25, the base body of the EUV collector 24 has further through-holes 25a and 25b. Through-hole 25a serves to allow the tin droplets 15 to pass from the tin droplet generator 16 to the source area 19. Through-hole 25b serves to allow the tin droplets 15, or debris generated in the source area 19 in the forward direction of the tin trajectory, to pass from the source area 19 to the tin collector 18. Through-holes 25a and 25b are arranged perpendicular to the main beam direction 17, respectively, at the level of the plasma source area 19 and the focal point of the EUV collector 24 located there.

[0044] The base body of the EUV collector can be actively cooled. For this purpose, the base body of the EUV collector 24 is in thermal contact with a cooling device 24a, which is shown schematically in Fig. 2. The cooling device 24a can include cooling channels in the base body of the EUV collector 24 through which a cooling medium is circulated. The cooling medium can be circulated in a closed loop via such cooling channels. Alternatively or additionally to active cooling, the cooling device 24a can have at least one heat sink for the passive dissipation of heat energy from the base body of the EUV collector 24. Such a heat sink can have an enlarged surface area and can, for example, have cooling fins.

[0045] The EUV collector 24 has a collector area designed such that, in a desired target state, the suppression of the pump light 20 reaching the intermediate focus 26 is better than 1 x 10'. 4and especially in the 1 x 10' range 5 This suppression is achieved by diffracting the stray light using a collector grating structure. Examples of such grating structures, or other types of diffraction structures, are known from DE 102019200698 A.

[0046] The field facet mirror FF is arranged in the beam path of the EUV useful light 3 after the intermediate focus 26 in the area of ​​a femfield of the EUV useful light 3.

[0047] The EUV collector 24 and other components of the light source 2, which may include the tin droplet generator 16, the tin collector 18, and the focusing lens 23, are arranged in a vacuum housing 27. The vacuum housing 27 has a through-opening 28 in the area of ​​the intermediate focus 26. In the area where the pump light 20 enters the vacuum housing 27, the latter has a pump light inlet window 29. Parts of the cooling device 24a may also be arranged outside the vacuum housing 27, contrary to the schematic representation in Fig. 2.

[0048] The EUV collector 24 has a reflective surface area in the form of a reflective surface 28, which is not shown completely in Fig. 2, but rather as broken in its surface areas beyond the through-openings 25a, 25b. The reflective surface area, or reflective surface 28, of the EUV collector 24 has the shape of a segment of an ellipsoid with two ellipsoid focal points. The source area 19 lies at one of the ellipsoid focal points and the collection area 26 at the other of the ellipsoid focal points of this ellipsoidal shape of the reflective surface 28.

[0049] The reflective surface 28 has a maximum collecting angle of at least 90° for useful light beams emanating from the source area 19. Depending on the design of the EUV collector 24, this maximum collecting angle can also be larger and can be, for example, at least 95°, at least 100°, at least 105°, at least 110°, at least 115°, or even at least 120°. Depending on the design of the EUV collector 24, the maximum collecting angle can also be greater than 120°. This maximum collecting angle is not shown in Fig. 2 due to the fractional representation of the reflective surface 28 and the base body of the EUV collector 24.

[0050] The parameters of an ellipsoidal shape of the reflecting surface or reflecting surface area 28 of the EUV collector 24 are explained in more detail below with reference to Fig. 3. The figure shows the basic ellipsoidal shape of the reflecting surface area 28 with focal points Fi, F2 and semi-axes a,b. A reflecting surface actually used for reflecting the EUV useful light 3 is shown as a solid line, while a supplementary area completing the entire ellipsoid, which does not exist in reality, is shown as a dashed line.

[0051] The source area 19 lies in the region of focus Fi. The collecting area 26 lies in the region of the second focus F2 of the ellipsoid. The through-holes 25, 25a, and 25b are omitted in Figures 3f.

[0052] Figure 3 shows selected individual beams of the EUV illuminant 3, which are guided from the first focal point Fi to the second focal point F2. In particular, one individual beam 3 is shown. ma x, which represents the maximum collecting angle of the reflective surface area 28 for useful light beams emanating from the source area or the focal point Fi. This collecting angle is labelled Q in Fig. 3 and lies in the meridional plane, i.e., in the plane of the drawing in Fig.

[0053] 3 spanned between the main beam direction 17, which is also called the optical axis oA, i.e. between a connecting line between the two ellipsoid focal points Fi, F2, and this maximum collecting angle single beam 3 max.

[0054] In the embodiment according to Fig. 3, the maximum collecting angle Q is approximately 145°.

[0055] The following applies to the ratio of the semi-axes a (major semi-axis) and b (minor semi-axis) of the ellipsoid defining the reflection area 28:

[0056] a / b ~ 1.73

[0057] Depending on the design of the EUV collector 24, the maximum collecting angle Q is greater than 120°.

[0058] The reflective surface area 28 is rotationally symmetric about the optical axis oA with respect to its basic reflection shape, i.e., rotationally symmetric about the connecting line between the two ellipsoid focal points Fi, F2. The maximum convergence angle £1 is therefore greater than 120° for all planes that contain the optical axis oA and in which a useful light ray 3 passes.

[0059] Furthermore, Fig. 3 shows an angle of incidence α of the EUV useful light 3 collected by the reflection surface area 28 into the illumination optics 6 following the collection area 26, which are only schematically indicated in Fig. 3, i.e., for example, the angle of incidence α towards the field facet mirror FF. The following applies to this angle of incidence α:

[0060] a = 180° - Q

[0061] In the embodiment according to Fig. 3, the reflective surface area 28 is entirely contiguous, i.e., it is a single piece and represents, for example, a reflective coating on a one-piece base body.

[0062] Fig. 4 shows another embodiment of a reflective surface area 28 of the EUV collector 24. Components, functions and parameters corresponding to those already explained above with reference to Figures 1 to 3 and in particular with reference to Fig. 3 bear the same reference numbers and are not discussed again in detail.

[0063] An ellipsoidal basic shape of the reflection surface area 28 according to Fig. 4 has a principal axis ratio a / b of approximately 4.1. This results in a larger collecting angle Q of approximately 165° compared to the embodiment according to Fig. 3. The angle of incidence a for the illumination optics 6 is then approximately 15° for the reflection surface area 28 according to Fig. 4. Fig. 5 shows another embodiment of a reflection surface area 28 of the EUV collector 24. Components, functions, and parameters that correspond to those already explained above with reference to Figures 1 to 4 bear the same reference numbers and are not discussed again in detail.

[0064] The reflective surface area 28 of the EUV collector 24 according to Fig. 5 is divided into two parts and has two detachably connected reflective surface sub-areas 28a and 28b, which are detachably connected to each other via a separation or joining plane 29. In the embodiment according to Fig.

[0065] 5 the optical axis oA is perpendicular to the separation / joining plane 29.

[0066] The reflecting surface sub-areas 28a and 28b each represent a segment of an ellipsoid with two ellipsoid focal points Fi and F2. The ellipsoid focal points Fi and F2 coincide for both reflecting surface sub-areas 28a and 28b.

[0067] The source area 19 is located in an operating position of the collector 24 according to Fig. 5 in the area of ​​the first focal point Fi and the collection area 26 is located in the area of ​​the second focal point F2.

[0068] The through-openings 25, 25a and 25b are also not shown in the illustration according to Fig. 5. These could be arranged accordingly, as explained above in connection with Fig. 2.

[0069] The EUV collector 24 according to Fig. 5 also has a maximum collecting angle Q greater than 120°, which in the embodiment according to Fig. 5 is approximately 145°. The reflective surface section 28a, whose reflective surface is closest to the source area focal point Fi, is designed to be interchangeable as part of a collector exchange module. For example, such a collector exchange module 30 can have an exchange drive 31, which serves to replace the reflective surface section 28a currently in the operating position with a replacement reflective surface section corresponding to this reflective surface section 28a, which is stored in a reflective surface section magazine 32. The drive movement of the exchange drive 31 can be at least partially about a pivot axis 33, which is indicated in Fig. 5 and which can, for example, run parallel to the separation / joining plane 29.

[0070] The further reflection surface sub-area 28b, which is located further away from the source area focal point Fi compared to the replaceable reflection surface sub-area 28a, can be designed in a stationary position in the EUV collector 24 according to Fig. 5 such that, after the exchange of the collector exchange module 30, it again complements the exchange reflection surface sub-area 28b to form the entire ellipsoidal reflection surface of the EUV collector 24.

[0071] Fig. 6 shows a further embodiment of a reflective surface area 28 of the EUV collector 24. Components, functions and parameters corresponding to those already explained above with reference to Figures 1 to 5 and in particular with reference to Fig. 5 bear the same reference numerals and are not discussed again in detail.

[0072] An ellipsoidal basic shape of the reflective surface area 28 of the EUV collector 24 according to Fig. 6 corresponds to the embodiment according to Fig. 4, so that the EUV collector according to Fig. 6 again has a collecting angle λ1 in the range of 165° and an angle of incidence α into the illumination optics 6 in the range of 15°. The reflective surface area 28 is further subdivided into the interchangeable reflective surface sub-area 28a and the stationary reflective surface sub-area 28b, between which the separation / joining plane 29 is located.

[0073] The penetration openings or substrate designs and cooling techniques can be present in the EUV collectors 24 according to Figures 3 and 6 in the same way as described above in connection with, for example, Figure 2.

[0074] To produce a micro- or nanostructured component, the projection exposure system 1 is used as follows: First, the reflection mask 10 or the reticle and the substrate or wafer 11 are provided. Then, a structure on the reticle 10 is projected onto a photosensitive layer of the wafer 11 using the projection exposure system 1. Developing the photosensitive layer then creates a micro- or nanostructure on the wafer 11, thus producing the microstructured component.

[0075] During operation of the projection exposure system 1, the condition of the EUV collector 24, in particular its local distribution of reflectivity across the collector surface, is monitored. If the monitoring reveals a degradation of the EUV collector 24 beyond a predefined tolerance value, especially for IR suppression, the EUV collector 24 or the reflective surface section 28a can be replaced.

Claims

Patent claims 1. EUV collector (24) for use in an EUV projection exposure system (1), wherein the EUV collector (24) is designed to guide EUV useful light (3) from a source area (19) to a collection area (26), wherein the EUV collector (24) has at least one reflection surface area (28) having the shape of a section of an ellipsoid with two ellipsoid focal points (Fi, F2), wherein the source area (19) is located in the region of one of the ellipsoid focal points (Fi) and the collection area (26) is located in the region of the other of the ellipsoid focal points (F2), wherein the reflection area (28) for useful light beam paths emanating from the source area (19) has a maximum collecting angle £1 which is at least 90°.

2. EUV collector according to claim 1, characterized in that the maximum collecting angle £1 for all planes containing the optical axis (oA) and in which a useful light beam passes is at least 90°.

3. EUV collector according to claim 2, characterized in that the reflection surface area (28) is rotationally symmetric about the connecting line (oA) between the two ellipsoid focal points (Fi, F2).

4. EUV collector according to one of claims 1 to 3, characterized in that the reflective surface area (28) has at least one has a passage opening (25, 25a, 25b) for the passage of pump radiation (20) and / or plasma medium (15) of an EUV plasma source to generate a plasma in the source area (19).

5. EUV collector according to claim 4, characterized in that the at least one passage opening (25) for the passage of the pump radiation (20) is arranged in the area of ​​a point of intersection of a connecting line (oA) between the two ellipsoid focal points (Fi, F2) through a basic shape of the ellipsoid.

6. EUV collector according to claim 4 or 5, characterized in that the at least one passage opening (25a, 25b) for the passage of the plasma medium (15) is arranged at a distance from a point of intersection of the connecting line (oA) between the two ellipsoid focal points (Fi, F2) through a basic shape of the ellipsoid.

7. EUV collector according to one of claims 1 to 6, characterized by exactly one contiguous reflective surface area (28).

8. EUV collector according to one of claims 1 to 7, characterized in that the reflective surface area (28) is operatively connected to a cooling device (24a).

9. EUV collector (24) for use in an EUV projection exposure system (1), wherein the EUV collector (24) is designed to guide EUV useful light (3) from a source area (19) to a collection area (26), wherein the EUV collector (24) has a reflective surface area (28) with at least two reflective surface sub-areas (28a, 28b) that are detachably connected to each other, each of which represents a sub-area of ​​a shape of a section of an ellipsoid with two ellipsoid focal points (Fi, F2), wherein both ellipsoid focal points for the at least two reflection surface sub-areas (28a, 28b) coincide, the source area (19) being located in the area of ​​one of the ellipsoid focal points (Fi) of the reflection surface sub-areas (28a, 28b) and the collecting area (26) being located in the area of ​​the other of the ellipsoid focal points (F2) of the reflection surface sub-areas (28a, 28b).

10. EUV collector according to claim 9, characterized in that the reflection surface area (28) for useful light beam paths emanating from the source area (19) has a maximum collecting angle £1 which is at least 90°.

11. EUV collector according to claim 9 or 10, characterized in that the reflecting surface sub-area (28a) whose reflecting surface is closest to the source area focal point (Fi) is designed to be interchangeable as part of a collector interchangeable module (30).

12. Lighting system with an EUV collector (24) according to one of claims 1 to 11 and with a lighting optic (6) for illuminating an object field (4) in which an object (10) to be imaged can be arranged, with the EUV useful light as the illumination light (3).

13. Optical system with an illumination system according to claim 12 and with a projection optic (7) for imaging the object field (4) into an image field (8) in which a substrate (11) can be arranged onto which a section of the object (10) to be imaged is to be imaged.

14. Projection exposure system (1) with an optical system according to claim 13 and with an EUV light source (2).

15. Method for manufacturing a structured component comprising the following process steps: Providing a reticulum (10) and a wafer (11), projecting a structure on the reticulum (10) onto a photosensitive layer of the wafer (11) using the projection exposure system according to claim 14, - Creating a micro- and / or nanostructure on the wafer (11).

16. Structured component, manufactured according to a method according to claim 15.

Images