Illumination optical unit for projection lithography, and method for monitoring such an illumination optical unit

Abstract

An illumination optical unit (11) for projection lithography comprises a transmission facet mirror (6), an illumination specification facet mirror (7), and a monitoring device (28). The latter comprises at least one spatially resolving monitoring sensor (29) and a satellite facet (30) which belongs to the transmission facet mirror (6) and is associated with precisely one monitoring-transmission facet (21). The satellite facet (30) is oriented such that monitoring light (3) from a monitoring light source (2) is guided along a monitoring light channel (31) towards the monitoring sensor (29) via the satellite facet (30) and an illumination specification facet (25) to be monitored which is associated with the monitoring-transmission facet (21). The result is an illumination optical unit for which tilting of illumination specification facets of an illumination specification facet mirror can be effectively monitored.

Description

[0001] Illumination optics for projection lithography and method for monitoring such an illumination optics

[0002] This patent application claims priority from German patent application DE 10 2023 209 699.4, the contents of which are incorporated herein by reference.

[0003] The invention relates to an illumination optics system for projection lithography. Furthermore, the invention relates to a method for monitoring such an illumination optics system, an optical system comprising such an illumination optics system, a projection exposure system comprising such an optical system, a method for producing a micro- or nanostructured component using such a projection exposure system, and a micro- or nanostructured component produced using this method.

[0004] An illumination optics for projection lithography is known from DE 10 2015 208 512 Al and the references given therein.

[0005] It is an object of the present invention to further develop an illumination optics of the type mentioned at the outset such that a tilting of illumination preset facets of an illumination preset facet mirror can be effectively monitored.

[0006] This object is achieved according to the invention by an illumination optics with a monitoring device having the features specified in claim 1 and by a monitoring method having the features specified in claim 10. According to the invention, it was recognized that when using at least one satellite facet, tilts of the illumination specification facet to be monitored translate into corresponding displacements of the monitoring light channel, which is guided via the respective satellite facet. These displacements of the monitoring light channel can be detected by sensors as corresponding displacements of a light channel impact point on the spatially resolving monitoring sensor of the monitoring device and thus monitored. Location differences between a desired impact point of the monitoring light channel and an actual impact point of the monitoring light channel on the sensor are a measure of tilts of the illumination specification facet to be monitored.In particular, mechanical and / or, assuming appropriate actuators for the illumination specification facet, capacitive and / or thermal drifts of the illumination specification facets can be effectively monitored. The monitoring light source can be identical to the illumination light source, i.e., the light source that generates the illumination light for projection lithography. The transmission facet mirror can be arranged in a field plane of a beam path of the illumination light. Parallel processing of several monitoring light channels and thus simultaneous monitoring of several illumination specification facets can be provided by the monitoring device of the illumination optics. The illumination specification facet mirror can be arranged in or near a pupil plane of a beam path of the illumination light.Alternatively, the illumination-specifying facet mirror can be arranged at a distance from a pupil plane of a beam path of the illumination light. The transmission facets of the transmission facet mirror can be tiltable by actuators. This can be used to specify a respective illumination channel for the illumination light, which is guided to the object field via one of the transmission facets and an illumination-specifying facet assigned to this transmission facet via a respective tilt position.

[0007] The at least one monitoring sensor of the monitoring device can provide a sensor area in the range between 10 mm x 10 mm and 100 mm x 100 mm.

[0008] In particular, the illumination light source that generates the illumination light can be used as a monitoring light source.

[0009] For example, the monitoring system may include 10,000 satellite facets.

[0010] An embodiment of the illumination optics according to claim 2 enables monitoring of a corresponding plurality of illumination preset facets to be monitored, which are assigned to the satellite facets. Each illumination preset facet to be monitored can be assigned a satellite facet of the monitoring device via a corresponding monitoring transmission facet. Monitoring, in particular, of all illumination preset facets of the illumination optics via corresponding satellite facets of the monitoring device is possible.

[0011] A spatial proximity between the respective satellite facet and its associated monitoring / transmission facet according to claim 3 ensures that comparable drift causes, which arise, for example, due to far-field illumination of the transmission facet mirror, can be monitored. A distance between the satellite facet and its associated monitoring / transmission facet can correspond to a typical extension of a transmission facet. If the transmission facet mirror is designed in modules, the satellite facet, on the one hand, and its associated monitoring / transmission facet, on the other hand, can be selected such that both facets belong to the same module of the transmission facet mirror.

[0012] An arrangement of the at least one monitoring sensor according to claim 4 has proven advantageous due to corresponding installation space requirements. Two monitoring sensors can be arranged next to the shorter sides of the object field, i.e., next to the shorter field extensions of the object field, such that the object field lies between the two monitoring sensors.

[0013] The design of the monitoring device with a separate monitoring light source according to claim 5 can expand the processing capabilities of the monitoring device. The monitoring light beam path of the separate monitoring light source can be coupled into a light guide of the illumination optics in the area of ​​an intermediate focus. Alternatively or additionally, the illumination light source can be used as a monitoring light source.

[0014] Monitoring light of multiple wavelengths according to claim 6 enables parallel processing of the monitoring light channels assigned to these wavelengths. At least one spectrally selective monitoring sensor can be used here. A diffractive element, in particular a grating, can be part of the wavelength-selective monitoring sensor. Alternatively or additionally, a wavelength-selective coating, in particular an interference coating, can be part of the wavelength-selective monitoring sensor. The then wavelength-selective monitoring sensor can have a wavelength-dependent filter. Such a monitoring sensor can be designed in the manner of a Bayer sensor, i.e., in the manner of an image sensor that operates according to the concept of a Bayer matrix. Pixels of such an image sensor can be assigned different colors of a wavelength range to be covered, analogous to the RGB division of the Bayer matrix.

[0015] A transmission facet mirror and / or an illumination-presetting facet mirror according to claim 7 can be designed as a MEMS mirror. The division of the transmission facets and / or the illumination-presetting facets into several individual mirrors, in particular into several individual mirrors of a MEMS mirror device, increases the flexibility of use of the illumination optics. The advantages of the monitoring device are particularly evident when monitoring illumination-presetting facets, which in turn are constructed from a plurality of individual illumination-presetting mirrors.

[0016] With the aid of a monitoring device according to claim 8, effective tilt position monitoring of all individual illumination preset mirrors belonging to a lighting preset facet is possible. These individual illumination preset mirrors can be scanned via the monitoring scanning unit. Designing the monitoring light source as a light source grid according to claim 9 enables parallel processing for detecting tilts of individual illumination preset mirrors of a lighting preset facet to be monitored as an alternative or additional monitoring option instead of the aforementioned monitoring scanning unit. In the case of the light source grid, parallel processing by the monitoring device is then possible.

[0017] The advantages of a monitoring method according to claim 10 correspond to those explained above with reference to the illumination optics with the monitoring device. The monitoring of the illumination preset facets to be monitored can be carried out sequentially and / or in parallel. During monitoring, a monitoring scanning unit can be used for the sequential monitoring of corresponding illumination preset facets and / or individual illumination preset mirrors, as already explained above. During monitoring, a light source grid of a monitoring light source can be used, as also already explained above, for the parallel tilt position monitoring of a plurality of illumination preset facets and / or a plurality of individual illumination preset mirrors. Cross-correlation techniques can be used for comparison within the framework of the monitoring method.

[0018] The monitoring process can be performed parallel to the operational operation of the illumination optics. Alternatively or additionally, the monitoring process can be performed during operational breaks of the projection exposure system, to which the illumination optics belongs. The monitoring process can be used, in particular, to monitor static alignment errors, manufacturing or indication errors, as well as general misalignments of the illumination facets to be monitored. Alternatively or additionally, dynamic tilt position deviations can be monitored, for example, the effect of thermal effects and / or a service life-related change in the illumination facets or a facet actuator.

[0019] When measuring and comparing the impact points, diffraction effects that may occur along the monitoring light channels can be taken into account.

[0020] The assignment method according to claim 11 specifies boundary conditions that can improve the quality of the monitoring result. As long as a minimum distance between predetermined target points of incidence of different monitoring light channels on the monitoring sensor is maintained, the corresponding monitoring light channels can be reliably distinguished when evaluating the comparison result of the monitoring method and thus clearly assigned to the satellite facets and thus to the lighting specification facets to be monitored. As long as a maximum distance between the satellite facet and its assigned monitoring transmission facet is maintained, it is ensured that distance-related deviations between the tilt position influences on the satellite facet on the one hand and on its assigned monitoring transmission facet on the other hand are not undesirably high.

[0021] Advantages of an optical system according to claims 12 and 13, a projection exposure apparatus 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 illumination optics according to the invention and the monitoring method according to the invention.

[0022] The substrate can be a wafer. In particular, a structured semiconductor component, in particular a microchip, such as a memory chip, can be produced.

[0023] Embodiments of the invention are explained in more detail below with reference to the drawings, in which:

[0024] Fig. 1 shows a highly schematic meridional section of a projection exposure system for EUV microlithography with a light source, an illumination optics and a projection optics, with an insert showing a plan view of an object field of the projection exposure system;

[0025] Fig. 2 schematically and also in meridional section a beam path of selected individual beams of illumination light within the illumination optics according to Fig. 1, starting from an intermediate focus up to a reticle or object arranged in the object plane of the projection optics in the region of the illumination or object field;

[0026] Fig. 3 is a plan view of a first facet mirror of the illumination optics, which is arranged in a field plane of the illumination optics and in an illumination far-field of the light source and is also referred to as a transmission facet mirror or as a field facet mirror, wherein an array arrangement of individual mirror units, each formed from a sub-array of individual mirrors of the first facet mirror (not visible in Fig. 3), is shown;

[0027] Fig. 4 shows, in comparison to Fig. 3, an enlarged, exemplary and more detailed, but still schematic, one of the individual mirror units, designed as a sub-array of the individual mirrors;

[0028] Fig. 5 is a plan view of an illumination presetting facet mirror of the illumination optics, which is arranged at a distance from a pupil plane of the illumination optics and is also referred to as a second facet mirror;

[0029] Fig. 6 schematically shows the illumination optics of the projection exposure system including a monitoring device, wherein an illumination channel for illuminating the object via a transmission facet of the transmission facet mirror and an illumination specification facet of the illumination specification facet mirror is shown in dotted lines and a monitoring light channel for applying light to a monitoring sensor of the monitoring device via a satellite facet of the transmission facet mirror and the illumination specification facet of the illumination channel is shown in solid lines;

[0030] Fig. 7 shows a further embodiment of the illumination optics with components of a further embodiment of the monitoring device, comprising a monitoring light source for monitoring light that is separate from the light source for the illumination light and is guided along a monitoring light channel via a satellite facet of the transmission facet mirror;

[0031] Fig. 8 shows in perspective a further embodiment of the illumination optics with a further embodiment of the monitoring device, comprising three monitoring light sources, each generating monitoring light of a specific wavelength, wherein the wavelengths generated by the monitoring light sources differ;

[0032] Fig. 9 shows, in a representation similar to Fig. 6, a further embodiment of the monitoring device with a monitoring scanning unit which is in signal connection with an actuator of the satellite facet highlighted in Fig. 9;

[0033] Fig. 10 shows, in a representation similar to Fig. 3, a plan view of the transmission facet mirror, highlighting a distribution of individual transmission mirrors used to illuminate the object with a specific illumination setting and individual transmission mirrors not used for this illumination, each of which is distributed over an entire usable area of ​​the transmission facet mirror;

[0034] Fig. 11 shows a plan view of the object field of the projection exposure system, which in this case is rectangular, and to the right and left of this a sensor surface of a spatially resolving monitoring sensor of the monitoring device, wherein points of incidence of monitoring light channels in the manner of the monitoring light channel according to Fig. 6 on the sensor surfaces are shown schematically;

[0035] Fig. 12 shows one of the sensor surfaces of the monitoring device, wherein a distribution of impact points of the monitoring light channels is shown in the manner of Fig. 11 after carrying out an assignment method of satellite facets to illumination specification facets to be monitored, wherein the assignment method leads to a sufficient spatial distance between the impact points;

[0036] Fig. 13 shows, in a representation similar to that of Fig. 9, an embodiment of the monitoring device with a monitoring light source which is designed as a light source grid, wherein all light sources of the light source grid are activated and wherein a monitoring light channel of the monitoring device is illustrated, starting from a center of the light source grid;

[0037] Fig. 14 shows, in a representation similar to Fig. 13, an operating situation of the monitoring device according to Fig. 13, wherein only a single light source of the light source grid is active.

[0038] A projection exposure system 1 for microlithography, shown in Figure 1 in a highly schematic and meridional section, has a light source 2 for illumination light 3. The light source 2 is an EUV light source that generates light in a wavelength range between 5 nm and 30 nm. This can be an LPP (laser-produced plasma) light source, a DPP (discharge-produced plasma) light source, or a synchrotron radiation-based light source, for example, a free-electron laser (FEL).

[0039] A transmission optics system 4 is used to guide the illumination light 3, emanating from the light source 2. This system has a collector 5, shown in Fig. 1 only with regard to its reflective effect, and a transmission facet mirror 6, which will be described in more detail below and is also referred to as a first facet mirror or a field facet mirror. An intermediate focus 5a of the illumination light 3 is arranged between the collector 5 and the transmission facet mirror 6. A numerical aperture of the illumination light 3 in the region of the intermediate focus 5a is, for example, NA = 0.182. Downstream of the transmission facet mirror 6 and thus the transmission optics system 4 is an illumination specification facet mirror 7, which is also referred to as a second or further facet mirror and will also be explained in more detail below. The optical components 5 to 7 are components of an illumination optics system 11 of the projection exposure system 1.

[0040] The transmission facet mirror 6 is arranged in a field plane of the illumination optics 11.

[0041] The illumination-presetting facet mirror 7 of the illumination optics 11 is arranged at a distance from the pupil planes of the illumination optics 11. Such an arrangement is also referred to as a specular reflector. Alternatively, the illumination-presetting facet mirror 7 can also be arranged in the region of a pupil plane of the illumination optics 11 and is then referred to as a pupil facet mirror.

[0042] Downstream of the illumination preset facet mirror 7 in the beam path of the illumination light 3 is a reticle 12, which is arranged in an object plane 9 of a downstream projection optics 10 of the projection exposure system 1. The projection optics 10 is a projection lens. The illumination optics 11 illuminates an object field 8 on the reticle 12 in the object plane 9 in a defined manner. The object field 8 simultaneously represents an illumination field of the illumination optics 11. In general, the illumination field is designed such that the object field 8 can be arranged in the illumination field.

[0043] The illumination preset facet mirror 7, like the transmission facet mirror 6, is part of a pupil illumination unit of the illumination optics and serves to illuminate an entrance pupil 12a in a pupil plane 12b of the projection optics 10 with the illumination light 3 having a preset pupil intensity distribution. The entrance pupil 12a of the projection optics 10 can be arranged in front of the object field 8 or after the object field 8 in the illumination beam path.

[0044] Fig. 1 shows the case in which the entrance pupil 12a is arranged after the object field 8 in the illumination beam path. In this case, the pupil distance PA of the second facet mirror 7 from the pupil plane 12b results from the sum of the z-distance PA1 of the second facet mirror 7 to the object plane 9 and the z-distance PA2 of the object plane 9 to the pupil plane 12b. The following therefore applies: PA = PA1 + PA2. The pupil distance PA can alternatively also be measured in the beam direction. To facilitate the representation of positional relationships, a Cartesian xyz coordinate system is used below. In Fig. 1, the x-direction runs perpendicular to the plane of the drawing. The y-direction runs to the right in Fig. 1. The z-direction runs downwards in Fig. 1. The coordinate systems used in the drawing each have x-axes that run parallel to one another.The course of a z-axis of these coordinate systems follows a respective main direction of the illumination light 3 within the respective figure under consideration.

[0045] The object field 8 has an arcuate or partially circular shape and is bounded by two parallel circular arcs and two straight side edges that run in the y-direction with a length yo and are spaced apart by a distance xo in the x-direction. The aspect ratio xo / yo is 13 to 1. An insert in Fig. 1 shows a plan view of the object field 8 (not to scale). One boundary shape 8a is arcuate. In an alternative and equally possible object field 8, its boundary shape is rectangular, also with an aspect ratio xo / yo.

[0046] During a projection exposure, the reticle 12 is displaced along an object displacement direction y through the object field 8.

[0047] The projection optics 10 is only partially and highly schematically indicated in Fig. 1. Shown are an object-field-side numerical aperture 13 and an image-field-side numerical aperture 14 of the projection optics 10. The image-field-side numerical aperture 14 can be in the range between 0.2 and 0.8 and can be, for example, 0.3, 0.33, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, or even 0.75. Between the indicated optical components 15, 16 of the projection optics 10, which can be designed, for example, as mirrors reflecting the EUV illumination light 3, there are further optical components of the projection optics 10 (not shown in Fig. 1) for guiding the illumination light 3 between these optical components 15, 16.

[0048] The projection optics 10 projects the object field 8 into an image field 17 in an image plane 18 on a wafer 19, which, like the reticle 12, is supported by a holder (not shown in detail). Both the reticle holder and the wafer holder can be displaced in both the x-direction and the y-direction via corresponding displacement drives. The installation space required for the wafer holder is shown in Fig. 1 at 20 as a rectangular box. The installation space required 20 is cuboid-shaped with an extension in the x-, y-, and z-directions that depends on the components to be accommodated therein. The installation space requirement 20 has, for example, an extension of 1 m in the x-direction and in the y-direction, starting from the center of the image field 17. In the z-direction, the installation space requirement 20 also has an extension of, for example, 1 m, starting from the image plane 18.

[0049] The illumination light 3 must be guided in the illumination optics 11 and the projection optics 10 in such a way that it is guided past the installation space requirement 20 in each case.

[0050] The transmission facet mirror 6 has a plurality of transmission facets 21, which are also referred to as first facets. The transmission facet mirror 6 can be designed as a MEMS mirror. The transmission facets 21 are individual transmission mirrors ES that can be switched between at least two tilt positions (see, for example, Figs. 7 and 8), which are designed as micromirrors. The transmission facets 21 can be designed as micromirrors that can be tilted about two mutually perpendicular axes of rotation. Of these transmission facets 21, a row with a total of nine transmission facets 21 is schematically shown in the yz section according to Fig. 2, which are indexed from left to right with 2h to 2b in Fig. 2. In fact, the transmission facet mirror 6 has a significantly larger number of transmission facets 21. The individual transmission mirrors ES are grouped into the transmission facets 21 (cf.(See also, for example, Figures 7 and 13). These transmission facets 21 are also referred to as single-mirror groups, virtual field facets, or virtual facet groups.

[0051] Each of the transmission facets 21 guides a portion of the illumination light 3, also referred to as an illumination light sub-beam, via an illumination channel for partial or complete illumination of the object field 8. Via this illumination channel and an illumination light sub-beam 3i guided over it, each of the individual mirror groups or transmission facets 21 is assigned exactly one illumination preset facet 25 of the illumination preset facet mirror 7. In principle, each of the illumination preset facets 25 can in turn be constructed from a plurality of individual mirrors ES (see, for example, Fig. 7). The illumination preset facets 25 are also referred to below as second facets. If the second facet mirror 7 is arranged in the region of a pupil plane of the illumination optics 11, the illumination preset facets 25 are also referred to as pupil facets.

[0052] A single-mirror group or transmission facet 21 is a group of individual mirrors ES of the first facet mirror 6, which is imaged into the object field 8 by the same second facet 25. For further details of possible embodiments of the transmission facet mirror 6 and the projection optics 10, reference is made to WO 2010 / 099 807 A.

[0053] The illumination preset facet mirror 7 is part of an optical system via which transmission facets 21 are imaged at least in sections or subfields of the object field 8. At least some of the illumination preset facets 25 may illuminate only a partial area or subfield of the object field 8. These subfields are very individually shaped and also depend on the desired illumination direction distribution (pupil shape) in the object field 8, i.e., the illumination setting. The illumination preset facets 25 are therefore illuminated by very differently shaped virtual field facets, the shape of which corresponds precisely to the shape of the respective subfield to be illuminated. Each illumination preset facet 25 also contributes to different areas of the pupil depending on its location in the object field 8.

[0054] The illumination preset facet mirror 7 can be designed as a MEMS mirror, particularly when each of the illumination preset facets 25 is constructed from a plurality of individual mirrors ES. The illumination preset facets 25 are micromirrors that can be switched between at least two tilt positions. The illumination preset facets 25 are designed as micromirrors that can be tilted two-dimensionally and, in particular, can be tilted continuously and independently about two mutually perpendicular tilt axes, i.e., can be set to a multitude of different tilt positions. An example of a predefined assignment of individual transmission facets 21 to the illumination preset facets 25 is shown in Fig. 2. The illumination preset facets 25 assigned to the transmission facets 2h to 2b are indexed according to this assignment.Due to this assignment, the lighting preset facets 25 are illuminated from left to right in the order 25e, 25s, 25s, 254, 25i, 25?, 25s, 252 and 25g.

[0055] The indices 6, 8 and 3 of the facets 21, 25 belong to three illumination channels VI, VIII and III, which illuminate three object field points OF1, OF2, OF3, numbered from left to right in Fig. 2, from a first illumination direction. The indices 4, 1 and 7 of the facets 21, 25 belong to three further illumination channels IV, I, VII, which illuminate the three object field points OF1 to OF3 from a second illumination direction. The indices 5, 2 and 9 of the facets 21, 25 belong to three further illumination channels V, II, IX, which illuminate the three object field points OF1 to OF3 from a third illumination direction. The illumination channels I to IX are assigned corresponding illumination light sub-beams 3i to 39.

[0056] The illumination directions assigned to the illumination channels VI, VIII, III, the illumination channels IV, I, VII and the illumination channels V, II, IX are identical. The assignment of the transmission

[0057] The relationship between facets 21 and the illumination specification facets 25 is therefore such that, in the figuratively illustrated illumination example, a telecentric illumination of the object field 8 results.

[0058] The illumination of the object field 8 via the transmission facet mirror 6 and the illumination preset facet mirror 7 can be carried out in the manner of a specular reflector. The principle of the specular reflector is known from US 2006 / 0132747 A1.

[0059] Fig. 3 shows a plan view of an embodiment of the first facet mirror 6. This has a regular array arrangement of individual mirror units 26, which are bordered by a square in Fig. 3. Each of the individual mirror units 26 is designed as a sub-array of N x M individual mirrors ES. This sub-array has a plurality of array rows that extend along a row direction corresponding to an angle bisector of the xy coordinate system.

[0060] Some of the adjacent array rows are offset from one another by a portion of the extent of one of the individual mirror units 26, in particular by half of this extent of the respective individual mirror unit 26 along the array row. Depending on the design of the facet mirror 6, such an offset can be omitted entirely, resulting in an array arrangement composed entirely of rows and columns. Alternatively, all array rows can be offset from one another. Different offset amounts between different, adjacent array parts are also possible depending on the design of the facet mirror 6 and the requirements placed on the positioning of the individual mirror units 26. The first facet mirror 6 is designed for arrangement in a useful range of a far field of the light source 2.

[0061] Fig. 4 shows one of the individual mirror units 26, still schematically but in greater detail. It shows a subdivision of the individual mirror unit 26 into the sub-array of, in this case, 6 x 6 individual mirrors ES. In the embodiment shown, each of the individual mirror units 26 therefore has 36 individual mirrors ES. In the example according to Fig. 4, N = 6 and M = 6 applies to the N x M sub-array arrangement. N and M can be the same, can be different and can each be in the range between 2 and 64, for example 4, 8, 16, 32 or 64. Values ​​other than powers of two are also possible for N and M, for example 25 or 50. A 12 x 12 or a 24 x 24 sub-array is also possible, for example.

[0062] In the embodiment shown in Fig. 3, the first facet mirror 6 has an arrangement of the individual mirror units 26 within a circular envelope. Alternatively, the first facet mirror 6 can also have the individual mirror units 26 within an elliptical, rectangular, or even polygonal envelope.

[0063] Each of the individual mirror units 26 can contain several complete or partial individual mirror groups, which guide the illumination light 3 to different second facets 25 and are imaged in the object field 8 in an overlapping manner. The individual mirror groups, i.e., the transmission facets 21, can extend over several of the individual mirror units 26. Fig. 5 again shows a top view of an embodiment of the second facet mirror 7.

[0064] The second facets 25 of the second facet mirror 7 each have a circular edge and are in the form of a hexagonal closest packing. As an alternative to circular-edged second facets 25, rectangular or polygonal, in particular hexagonal, edges can also be provided. The second facets 25 can themselves be designed as individual mirror units in the manner of the individual mirror units of the first facet mirror 6 and, in this case, can be divided into a plurality of individual mirrors in the manner of individual mirrors ES. In principle, the structure of the second facet mirror 7 can correspond to the structure of the first facet mirror 6 with regard to the subdivision into individual mirrors and individual mirror units.

[0065] In the embodiment according to Fig. 5, each of the second facets 25 can also be designed as a monolithic facet.

[0066] The second facets 25 of the second facet mirror 7 are arranged within an elliptically edged envelope. Alternatively, other envelope shapes are also possible here, for example, a circular envelope, a rectangular envelope, or even a polygonally edged envelope.

[0067] Fig. 6 schematically shows an embodiment of the illumination optics 11. Components and functions corresponding to those already explained above with reference to Figs. 1 to 5 have the same reference numerals and will not be discussed in detail again. Fig. 6 illustrates, in dotted lines, the course of an illumination channel 27 between the light source 2 or the intermediate focus 5a, a selected transmission facet 21 of the transmission facet mirror 6, an illumination preset facet 25 assigned to this transmission facet 21, and the object field 8 on the reticle 12. The illumination preset facet 25 is assigned to the monitoring facet 21 via the illumination channel 27.The transmission facet 21 is transferred into the object field 8 via the illumination channel 27 in such a way that either the illumination channel 27 illuminates the entire object field 8 or a partial field of the object field 8, depending on the grouping selection of the individual mirrors ES, which, as an individual mirror group, belong to the respective transmission facet 21. Such a grouping of the individual mirrors ES, which in particular results in the edge contour of the transmission facet 21 according to Figure 6, is not shown in Figure 6.

[0068] Fig. 6 also illustrates a monitoring device 28 of the illumination optics 11. The monitoring device 28 includes a spatially resolving monitoring sensor 29, which is designed as a PSD, CMOS, or CCD array with a plurality of sensor pixels, for example, 10,000 x 10,000 sensor pixels. The spatially resolving monitoring sensor 29 can also have a significantly smaller number of sensor pixels, for example, 10 x 10, 100 x 100, or 1,000 x 1,000. An aspect ratio of the number of pixels other than one is also possible. In general, a quadrant detector can also be used as the monitoring sensor 29.

[0069] The monitoring device 28 also includes a satellite facet 30 in the form of, for example, exactly one individual mirror or a plurality of selected individual mirrors of the transmission facet mirror 6. The satellite facet 30 can be tilted independently by actuators about tilt axes parallel to the coordinates x and y.

[0070] Fig. 6 shows a monitoring light channel 31 from the light source 2 or the intermediate focus 5a via the satellite facet 30, the illumination specification facet 25, which simultaneously guides the illumination channel 27 according to Fig. 6, to an impact point or impact area 32 on the monitoring sensor 29. A typical diameter of the impact point of the monitoring light channel 31 on the monitoring sensor 29 can be 1 mm.

[0071] The object field 8 has a longer field extension along the x-field dimension and a shorter field extension along the y-field dimension. The monitoring sensor 29 is arranged at a distance from the object field 8 along the x-field dimension and, in the embodiment shown in Fig. 6, is located to the right of the shorter object field side of the object field 8. The monitoring sensor 29 can be arranged in the object plane 9; however, this is not mandatory. The monitoring sensor 29 can also be arranged at a distance from the object plane 9, for example, closer to the illumination specification facet mirror 7 than the reticle 12 or, alternatively, further away from it.

[0072] Due to the guidance via the same illumination preset facet 25, the satellite facet 30 is assigned to the transmission facet 21 highlighted in Fig. 6, which therefore represents a monitoring transmission facet 21. This assignment requires an orientation of the satellite facet 30 such that monitoring light, in this case the illumination light 3 generated by the light source 2, is guided from the light source 2, which then immediately represents a monitoring light source, via the satellite facet 30 and the illumination preset facet 25 highlighted in Fig. 6 as the illumination preset facet to be monitored along the monitoring light channel 31 to the monitoring sensor 29.

[0073] Tilts drx, dry of the illumination preset facet 25, which guides both the illumination channel 27 and the monitoring light channel 31, simultaneously lead to a displacement of the illumination channel 27 and the monitoring light channel 31, namely displacements dx along the x-coordinate and dy along the y-coordinate. The respective displacement dx, dy on the monitoring sensor 29 is a measure of the tilt dry, drx of the illumination preset facet 25 to be monitored about tilt axes parallel to the x and y coordinate axes. Accordingly, dy=f(drx) and dx=f(dry).

[0074] From the displacements dx, dy that can be measured via the monitoring sensor 29 between a target point of incidence 32s, which is predetermined, for example, within the scope of a calibration process, and the respectively measured actual point of incidence 32i of the monitoring light channel 31 on the monitoring sensor 29, it is possible to infer the actual tilts dry and drx of the monitored lighting specification facet 25.

[0075] When monitoring the lighting specification facets 25 of the lighting specification facet mirror 7 using the monitoring device 28, the following procedure can be followed:

[0076] First, satellite facets 30 are assigned to illumination preset facets 25 to be monitored. This can be done by assigning the satellite facets 30 to transmission facets 21, which, on the one hand, via the transmission facet 21 and the illumination channel 27 used for projection exposure and, on the other hand, via the satellite facet 30 and the monitoring light channel 31, apply light to the same illumination preset facet 25 to be monitored.

[0077] Depending on the boundary conditions of the assignment step, the satellite facet 30 can be closely adjacent to the monitoring / transmission facet 21 assigned to it. A maximum distance that can be specified here can, for example, be the typical dimension of a monitoring / transmission facet 21. An assignment can, for example, be made with the boundary condition that the satellite facet 30 to be assigned is present on the same individual mirror unit 26 as at least a plurality of individual mirrors ES of the monitoring / transmission facet 21 to be assigned. It is also possible to use a multiple of the typical dimension of a monitoring / transmission facet for the method, as long as the spatial relationship between the monitoring / transmission facet and the satellite mirror is known with sufficient precision. A group of individual mirrors can therefore also be used as the monitoring / transmission facet 21.As an advantage, a larger distance between the satellite facet 30 and the monitoring transmission facet 21 associated with it allows the monitoring sensor 29 to be integrated into the scanner at a greater distance from the reticle 12.

[0078] After the assignment has been completed, the monitoring light, for example, the illumination light 3, is guided along the monitoring light channel 31 via the respective satellite facet 30 and the assigned illumination preset facet 25, and an actual point of incidence 32i of the monitoring light channel 31 on the monitoring sensor 29 is measured with spatial resolution. The actual point of incidence 32i is then compared with the predetermined target point of incidence 32s.

[0079] This comparison is performed using an evaluation device 33 of the illumination optics 11. The evaluation device 33 is in signal communication with a central control device 34 of the projection exposure system 1.

[0080] Depending on the comparison result of the monitoring process, compensatory countermeasures can be initiated. This can be done via the control device 34. If displacements of the impact points can be attributed to thermal drifts, thermal or mechanical compensation measures can also be taken.

[0081] Fig. 7 shows a further embodiment of a monitoring device 35, which can be used alternatively or in addition to the monitoring device 28 in a corresponding embodiment of the illumination optics 11 of the projection exposure system 1. Components and functions corresponding to those already explained above with reference to Figures 1 to 6, and in particular with reference to Figure 6, bear the same reference numerals and will not be discussed in detail again.

[0082] The illumination optics 11 according to Figure 7 is depicted as a specular reflector. Shown as an example are principal rays 36 guided via individual mirrors ES of the illumination-specifying facet mirror 7, as well as marginal rays 37 delimiting an illumination angle distribution to one side and marginal rays 38 delimiting the illumination angle distribution to the other side. This is illustrated in the fundamentally schematic representation according to Figure 7 by the fact that the principal rays 36 meet at a center of the entrance pupil 12a of the illumination optics 11. Accordingly, the marginal rays 37 on the one hand and 38 on the other hand meet in the beam path of the illumination light 3 after the object field 8 at opposite edge points of the entrance pupil 12a.

[0083] The illumination-presetting facet mirror 7 is arranged at a distance from the entrance pupil plane 12b of the projection optics 10, not shown in Figure 7. The entrance pupil 12a of the projection optics 10 is not accessible as an arrangement plane for the illumination-presetting facet mirror 7, since it lies in the beam path after the object field 8.

[0084] Figure 7 also shows two illumination channels 27i and 272, each limited by two individual beams, which are used to illuminate the reticle 12. The illumination channel 27i is limited by one of the main beams 36 and one of the marginal beams 37. The illumination channel 27i is guided, starting from the intermediate focus 5a, via a transmission facet 2h and an illumination preset facet

[0085] 251 towards the object field 8. The illumination channel 272, which is in turn limited by a main beam 36 and by a marginal beam 38 assigned to the opposite illumination angle, is guided via a transmission facet 2 h and an illumination specification facet

[0086] 252 towards object field 8.

[0087] The transmission facets 2h, 2h are formed from a group of individual mirrors ES of the transmission facet mirror 6. In the illustration, for example, 14x6 individual mirrors are selected. Other groupings are also possible, in particular groupings comprising a few to several hundred individual mirrors.

[0088] The illumination preset facet 251 is formed from 2x2 individual mirrors ES of the illumination preset facet mirror 7. In contrast, the illumination preset facet 252 is formed from 4x4 individual mirrors ES of the illumination preset facet mirror 7. Depending on the image shape and scale of a plasma image of the light source 2, it is also possible to assemble the illumination preset facets from other numbers or groupings of individual mirrors; in particular, 3x3 individual mirrors, 5x5, 6x6, or 7x7. Furthermore, it may be useful to use non-square groups, for example, 3x4, 3x5, 4x5, 4x6, 4x7, 5x7, or 6x7 individual mirrors. In the case shown in Figure 7, the lighting default facet 252 is significantly larger than the lighting default facet 251.

[0089] The monitoring device 35 according to Figure 7 has a monitoring light source 39 separate from the illumination light source 2. This can be designed, for example, as a laser diode.

[0090] The monitoring light source 39 is designed such that it generally allows illumination of the entire transmission facet mirror 6. A wavelength conversion screen 40 is arranged in the beam path of the monitoring light source 39.

[0091] The monitoring light source 39 can be a monochromatic laser diode. The wavelength conversion screen 40 can be a phosphor screen, for example, a screen comprising YAG aluminum phosphor.

[0092] The monitoring device 35 has two monitoring sensors 29i and 292, which are arranged on either side of the object field 8 at a distance in the x-coordinate direction, i.e., perpendicular to the object displacement direction y of the projection exposure system 1. Furthermore, it is also possible to arrange additional monitoring sensors 29i at a distance from one another in the x-direction in order to increase the effectively usable sensor area of ​​the monitoring device 35 and to measure more illumination preset facets simultaneously. Furthermore, it is also possible to place exactly one monitoring sensor 29, spaced from the object field 8 in the object displacement direction y.

[0093] A monitoring light channel 31 is shown in Figure 7 between the wavelength conversion screen 40, a satellite facet 30, designed as a single mirror ES on the transmission facet mirror 6, the illumination specification facet 252 and the monitoring sensor 292 of the monitoring device 35.

[0094] Due to the exposure to the same illumination preset facet 252, the monitoring light channel 31 shown in Figure 7 and the satellite facet 30 exposed by it are assigned to the illumination channel 272 and thus to the monitoring transmission facet 2h and the illumination preset facet 252 to be monitored. As already explained above in connection with the embodiment according to Figure 6, tilts drx, dry of the illumination preset facet 252 are transmitted into displacements dy, dx of the point of incidence 32 of the monitoring light channel 31 on the monitoring sensor 292.

[0095] By suitable tilt angle assignments of the individual mirrors ES on the facet mirrors 6 and 7, it can be ensured that the monitoring light 41 of the monitoring light source 39 does not undesirably impact the object field 8.

[0096] With reference to Figure 8, a further embodiment of the illumination optics 11 and a monitoring device 42 is described below, which can be used alternatively or in addition to the monitoring devices 28, 35 explained above. Components and functions corresponding to those already explained above with reference to Figures 1 to 7, and in particular with reference to Figures 6 and 7, bear the same reference numerals and will not be discussed in detail again.

[0097] Components or functional units of the illumination optics 11, which are shown in Figure 8, are the intermediate focus 5a, the transmission facet mirror 6, the illumination specification facet mirror 7 and, in this case, the arc-shaped object field 8. The schematic, perspective illustration in Figure 8 shows exemplary arrangements of the individual mirrors ES of the transmission facet mirror 6 on the one hand and the illumination specification facet mirror 7 on the other. Highlighted on the transmission facet mirror 6 are two transmission facets 2h and 2h, each of which is composed of a group of 18 individual mirrors ES. The assignment of the individual mirrors ES to the respective transmission facets 2h, 2h is such that an envelope of these transmission facets 2h, 2h is adapted in its shape to the arc shape of the object field 8.Illumination channels (not shown in detail) guide the illumination light from the intermediate focus 5a, on the one hand, via the transmission facet 2h and an illumination preset facet 251 assigned to the illumination preset facet mirror 7, as well as via the transmission facet 2h and an illumination preset facet 252 assigned to the illumination preset facet mirror 7, superimposed on one another, to illuminate the entire object field 8. The assigned illumination preset facets 251, 252 each contain four individual mirrors ES in a 2x2 arrangement. Other NxM arrangements of the individual mirrors ES are also possible, with N and M each regularly lying in the range between 1 and 10.

[0098] A monitoring light source 43 of the monitoring device 42 is designed to generate monitoring light 4h, 4h, and 4h, each of different wavelengths. The monitoring light 4h, for example, of a medium wavelength, emanates from a source location 441 of the monitoring light source 43 adjacent to the intermediate focus 5a and is guided along a monitoring light channel 3h via a satellite facet 30i, the illumination preset facet 252, to an impingement point 32i on the monitoring sensor 29i. The satellite facet 30i is thus assigned to the illumination preset facet 252 to be monitored.

[0099] The monitoring light source 43 further generates monitoring light 4h of a shorter wavelength than monitoring light 4h, which is guided along a monitoring light channel 3h from a source location 442, again adjacent to the intermediate focus 5a, to a satellite facet 302 and the illumination preset facet 251 to an impingement point 322 on the monitoring sensor 292. The satellite facet 302 is assigned to the illumination preset facet 25i to be monitored.

[0100] A third monitoring light channel 313, shown in Figure 8, is used to further monitor an individual mirror ES3 on the illumination specification facet mirror 7. It emanates from a source location 443, again adjacent to the intermediate focus 5a. Monitoring light 4h, which emanates from this third source location 443, has a wavelength that is longer than the wavelengths of monitoring light 4h and 4h, so that the three different wavelengths of monitoring light 4li, which emanates from the source locations 44i, can be spectrally discriminated by the monitoring device 42.

[0101] The monitoring light channel 3h runs from the source location 443 to another satellite facet 303 on the transmission facet mirror 6, via the individual mirror ES3 to be monitored on the illumination specification facet mirror 7, to another point of incidence 323 on the monitoring sensor 292. The satellite facet 303 is assigned to the individual mirror ES3 to be monitored. In contrast to the mirror groups ESi and ES2, ES3 is not exposed to light that must be imaged into the reticle 8. Such a configuration is useful for specifically measuring the tilt angle behavior of an individual mirror such as ES3, independent of scanner operation, since exactly one image 323 of this mirror is imaged onto the sensor. In contrast, in cases 32i and 322, there are 4 (2x2) image overlays of the images from 2h and 2h on the monitoring sensors 29 in this example.The measured images 32i and 322 are therefore averaged over the tilt angle deviations of the involved mirror groups 251 and 252.

[0102] The monitoring sensors 29i of the monitoring device 42 can be designed to be spectrally selective, so that these monitoring sensors 29i, 29i can determine, based on the wavelength of the monitoring light 4h, which point of incidence 32i belongs to which monitoring light channel 3li. In particular, parallel processing of an evaluation of the points of incidence 2li is possible using the monitoring device 42, so that the steps explained above in connection with the monitoring method—"guiding monitoring light 4li, measuring a target point of incidence 32; and comparing the actual point of incidence 32i with a predetermined target point of incidence"—can be performed in parallel.

[0103] Spectral selectivity or color decomposition via the 29i monitoring sensors makes it possible to capture several superimposed images simultaneously.

[0104] The monitoring light source 43 can be an RGB light source. The number of monitoring light channels 31i, each with different monitoring light wavelengths, can also be greater than three and can, for example, be in the range between three and 20 or even greater. In principle, monitoring light 41 of a different wavelength can be used for each lighting preset facet 25i to be monitored, so that all lighting preset facets 25i can be detected simultaneously with a correspondingly spectrally discriminating monitoring sensor 29.Groups of monitoring light channels 4 li, each with the same wavelength, which belong to monitoring light channels 3 li, whose target points of incidence on the monitoring sensor 29 differ spatially sufficiently, can also be formed, so that, for example, when using three wavelengths of the monitoring light 41 and 300 lighting specification facets 25i to be monitored, 100 lighting specification facets each with the same wavelength of the monitoring light 41 can be monitored.

[0105] The monitoring sensors 29i, 292, particularly in the monitoring device 42, can be CMOS sensors with a colored Bayer matrix adapted to the wavelengths of the monitoring light source 43. Bayer matrices are known, for example, from the technical article "Review of Bayer Pattern Color Filter Array (CFA) demosaicing with new quality assessment algorithms" by RA Maschal Jr., et al., ARL-TR-5061, January 2010.

[0106] Figure 9 shows, in a representation comparable to Figure 6, a further embodiment of a monitoring device 45, which can be used alternatively or in addition to one of the monitoring devices explained above. Components and functions corresponding to those already explained above with reference to Figures 1 to 8, and in particular with reference to Figure 6, bear the same reference numerals and will not be discussed in detail again.

[0107] In a lighting setting that is to be monitored by means of the monitoring device 45, a lighting specification facet 25 includes four individual mirrors ESi to ES4 which, when grouped together, form the lighting specification facet 25, corresponding, for example, to the lighting specification facets 25i of the embodiment according to Figure 8.

[0108] In the monitoring device 45, the satellite facet 30 is controlled by the control device 34 of the monitoring device 45, and is actuator-tiltable by tilt angles drx and dry, analogous to what was explained above, for example, in connection with the lighting specification facet 25 of the monitoring device 28 according to Figure 6. The control device 34 includes a monitoring scanning unit 46, which is in signal communication with the actuators of the satellite facet 30 used by the monitoring device 45.

[0109] When guiding the monitoring light 3 along the monitoring light channel 31, the monitoring scanning unit 46 controls the satellite facet 30 such that all four individual mirrors ESi to ES4 of the illumination specification facet 25 are scanned during the monitoring process of this illumination specification facet 25, which is illustrated in Figure 9 by arrows between the individual mirrors ESi to ES4.

[0110] As the scan progresses, impact points 32ESI to 32ES4 are assigned to the respective individual mirrors ESi to ES4, of which two impact locations 32ESI and 32ES2, assigned to the individual mirrors ESi and ES2, are shown in Figure 9. Based on these measured impact points 32ES, a comparison can then be made with the corresponding target impact points of the illumination specification facet 25. Figure 10 illustrates how many individual mirrors ES are available as satellite facets 30 in a typical illumination setting used for projection exposure. A top view of the transmission facet mirror 6 is shown, with those individual mirrors ES that are used in the set illumination setting being highlighted by an x ​​symbol.In addition to these used individual mirrors ES, there are 6 unused individual mirrors ES distributed practically evenly across the entire surface of the transmission facet mirror, which can be used as satellite facets 30 within the framework of one of the monitoring methods described above. The number of individual mirrors ES that can be used as satellite facets 30 is generally greater than the number of illumination preset facets 25 to be monitored, so that, in principle, all illumination preset facets used in a lighting setting can be monitored with regard to their current tilt position using the monitoring methods described above.

[0111] Figure 11 shows, by way of example, the result of a parallel measurement, for example, using a monitoring device similar to that of monitoring device 42, which can be generated with a larger number of different monitoring light wavelengths 4E. The points of incidence 32, each associated with a monitoring light wavelength, are illustrated by different symbols on the monitoring sensors 29i and 292. The points of incidence 32, which are associated with different light wavelengths 4li, partially overlap one another. Here, a spectral selectivity of the monitoring device 42, as explained above, can come into play.

[0112] Figure 11 shows a plan view of an object field 8, in this case rectangular, between sensor surfaces of the two monitoring sensors 29i and 292. The x-extension of the sensor surfaces can be in the range between 10% and 100% of the x-extension of the object field, for example, 25% to 75%. The y-extension of the sensor surfaces of the monitoring sensors 29i, 292 is generally larger than the y-extension of the object field actually used for the instantaneous exposure and can, for example, have a y-extension that corresponds to an entire y-scan across the object field 8, or a multiple thereof; for example, 200% or 500%. The thus enlarged monitoring sensor 29i can also be implemented at a distance from the object field.

[0113] The sensor surfaces of the monitoring sensors 29i can be rectangular and, in particular, square.

[0114] Figure 12 shows, in a representation similar to Figure 11, a distribution of approximately 100 points of incidence 32 on the sensor surface of one of the monitoring sensors 29 of one of the previously described embodiments of the monitoring device. This arrangement of the points of incidence 32 has a minimum distance between predetermined target points of incidence of various monitoring light channels on the monitoring sensor 29, so that these points of incidence 32 can be differentiated even if the respective actual points of incidence deviate from the target points of incidence due to tilting of the monitored illumination preset facets 25.

[0115] Using a corresponding assignment algorithm, the satellite facets 30 can be assigned to the respective illumination preset facets 25 to be monitored, ensuring a corresponding spatial distribution of the points of incidence 32 with a sufficient minimum distance between two adjacent target points of incidence. Figures 13 and 14 show a further embodiment of a monitoring device 47 that can be used instead of the monitoring devices described above. Components and functions corresponding to those already explained above with reference to Figures 1 to 12, and in particular with reference to Figures 6 to 12, bear the same reference numerals and will not be discussed in detail again.

[0116] A monitoring light source 48 in the monitoring device 47 is designed as a light source grid with individual sources 49 arranged in an NxM grid. Figures 13 and 14 show a 6x6 grid of individual sources 49.

[0117] With the aid of such a light source grid, the monitoring device 47 can monitor tilt positions of several individual mirrors ES of an illumination preset facet 25 to be monitored in parallel processing with the same monitoring result as was described above in connection with Figure 9 in the context of sequential scan processing.

[0118] Figures 13 and 14 illustrate a monitoring light channel which leads from a center of the light source grid of the monitoring source 48 via a satellite facet 30 and an illumination specification facet 25 with a total of 6x6 individual mirrors ES to an impingement point 32 on the monitoring sensor 29. In the embodiment according to Figures 13 and 14, the illumination specification facet 25 is designed as a 6x6 grid of individual mirrors ES. Figure 13 shows the situation in which all individual sources 49 of the monitoring light source 48 are activated. Also shown is the situation in which the illumination specification facet 25 is arranged in a pupil plane of the illumination optics, so that a grid of corresponding source images 50 of the individual sources 49 is generated on the illumination specification facet 25. The position of this grid of source images 50 can be determined as part of a calibration measurement.The distances between the individual sources 49 can be dimensioned such that the source images 50 are each assigned to exactly one individual mirror ES of the illumination specification facet.

[0119] When all 36 individual sources 49 are activated, in the situation shown in Figure 13, all 36 individual mirrors ES of the illumination preset facet 25 to be monitored can in principle be monitored with regard to their points of incidence via the monitoring light channel 31 to the sensor 29. Parallel monitoring is thus possible, as an alternative to the scanning variant of monitoring using the monitoring scanning unit 46 described above in connection with Figure 9.

[0120] To measure individual mirrors ES of the illumination preset facet 25 to be monitored, the operating situation shown in Figure 14 can be created, in which exactly one selected individual source 49 of the monitoring light source 48 is activated, whereas all other 35 individual sources 49 are deactivated. The tilt angle of this assigned individual mirror ES can then be monitored via the resulting monitoring light channel 31 via the satellite facet 30 and the individual mirror ES at the location of the source image 50 of the activated individual source 49. When comparing the respective actual point of incidence with the respective predetermined target point of incidence, techniques known in optics as cross-correlation techniques can be used.Such a cross-correlation can be used to determine a displacement of a specific impact point 32 or also to determine displacements of a plurality of impact points 32 in parallel by determining and evaluating a cross-correlation signal of a recording of the monitoring sensor 29 with a corresponding plurality of impact points 32i, each of which belongs to a monitoring light channel 3li.

[0121] In parallel with monitoring the illumination optics 11 using a monitoring device described above, a useful projection exposure for imaging the reticle 12 onto the wafer 19 can be carried out using a preset illumination setting.

[0122] To produce a microstructured component, in particular a highly integrated semiconductor device, for example a memory chip, using the projection exposure system 1, the reticle 12 and the wafer 19 are first prepared. Subsequently, a structure on the reticle 12 is illuminated with the illumination light 3 using the illumination optics 11 and projected onto a light-sensitive layer on the wafer 19 using the projection optics of the projection exposure system 1. By developing the light-sensitive layer, a microstructure is then created on the wafer 19, and from this, the micro- or nano-structured component is created.

[0123] The component produced may be a microchip, in particular a memory chip.

Claims

Patent claims 1. Illumination optics (11) for projection lithography, comprising a transmission facet mirror (6) with a plurality of transmission facets (21) for guiding illumination light (3) from an illumination light source (2) via illumination channels (27) defined by the transmission facets (21), along an illumination light beam path, comprising an illumination specification facet mirror (7) with a plurality of actuator-tiltable illumination specification facets (25) for superimposingly guiding the illumination light (3) via the illumination channels (27) via one of the transmission facets (21) in each case and one illumination specification facet (25) assigned via the respective illumination channel (27) to an object field (8) in which an object (12) to be illuminated can be arranged, wherein the illumination specification facet mirror (7) is part of an optics via which the transmission facets (21) are imaged at least in sections of the object field (8),with a monitoring device (28; 35; 42; 45; 47) comprising: — at least one spatially resolving monitoring sensor (29; 29i, 292), — at least one satellite facet (30) of the transmission facet mirror (6), which is assigned to exactly one of the transmission facets (21), which then represents a monitoring transmission facet, and is oriented such that monitoring light (3; 41) from a monitoring light source (2; 39; 43; 48) via the satellite facet (30) and one of the illumination specification facets (25) as the illumination specification facet to be monitored, which is assigned to the monitoring transmission facet via the illumination channel (27), is guided along a monitoring light channel (31) to the monitoring sensor (29; 29i, 292).

2. Illumination optics according to claim 1, characterized by a plurality of satellite facets (30).

3. Illumination optics according to claim 1 or 2, characterized in that the satellite facet (30) is closely adjacent to the monitoring transmission facet (21) assigned to it.

4. Illumination optics according to one of claims 1 to 3, characterized in that the object field (8) has a longer field extension along a first field dimension (x) and a shorter field extension along a second field dimension (y) perpendicular thereto, wherein the at least one monitoring sensor (29; 29i, 292) is arranged at a distance from the object field (8) along the first field dimension (x).

5. Illumination optics according to one of claims 1 to 4, characterized in that the monitoring light source (39; 43; 48) is designed as a light source separate from an illumination light source (2), wherein the monitoring light (41) is guided along a monitoring light beam path adjacent to the illumination channels (27) via at least one of the satellite facets (30) and the associated illumination preset facet (25) to be monitored.

6. Illumination optics according to one of claims 1 to 5, characterized by monitoring light (3; 41) of several wavelengths, wherein the at least one monitoring sensor (29i, 292) is designed to be wavelength-selective.

7. Illumination optics according to one of claims 1 to 6, characterized in that the transmission facets (21) are each divided into a plurality of individual transmission mirrors (ES) and / or that the illumination specification facets (25) are each divided into a plurality of individual illumination specification mirrors (ES).

8. Illumination optics according to claim 7, characterized in that the at least one satellite facet (30) is designed to be tiltable by an actuator, wherein the monitoring device (45) has a monitoring scanning unit (46) which is in signal connection with an actuator for tilting the at least one satellite facet (30).

9. Illumination optics according to one of claims 1 to 8, characterized in that the monitoring light source (48) is designed as a light source grid which is adapted to a grid of individual illumination specification mirrors (ES), each of which forms an illumination specification facet (25).

10. A method for monitoring an illumination optics (11) according to one of claims 1 to 9, comprising the following steps: Assigning satellite facets (30) to the lighting specification facets (25) to be monitored, Guiding monitoring light (3; 41) along at least one monitoring light channel (31) via the respective satellite facet (30) and the associated lighting specification facet (25) to be monitored, Measuring an actual point of impact (32) of the respective monitoring light channel (31) on the monitoring sensor (29), comparing the actual point of impact (32) with a predetermined target point of impact of the respective monitoring light channel (31).

11. The method according to claim 10, characterized in that during the assignment a minimum distance between predetermined target points of incidence of different monitoring light channels (31) on the monitoring sensor (29) is maintained and / or that during the assignment a maximum distance between the respective satellite facet (30) and the monitoring transmission facet (21) assigned to it, which is assigned to the illumination specification facet (25) to be monitored via an illumination channel (27), is not exceeded.

12. Optical system with an illumination optics according to one of claims 1 to 9 and with a projection optics for imaging the object field (8) into an image field (17) in which a substrate (19) can be arranged.

13. Optical system with an illumination optics according to one of claims 1 to 12 and with a monitoring light source (2; 39; 43; 48).

14. Projection exposure apparatus with an optical system according to claim 12 or 13 and with an illumination light source (2).

15. Process for producing a micro-structured component with the following process steps: Providing a reticle (12), Providing a wafer (19) with a coating sensitive to the illumination light (3), Projecting at least a portion of the reticle (12) onto the wafer (19) with the aid of the projection exposure system (1) according to claim 14, Developing the light-sensitive layer on the wafer (19) exposed to the illumination light (3).

16. Component manufactured by a method according to claim 15.

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