Method for measuring the actual orientation of a reflective surface of an actuator-tiltable single mirror and measuring device for carrying out the method

Abstract

To measure the actual orientation of a reflective surface of an actuator-tiltable single mirror (18 i ) of a single-mirror group of a faceted mirror device, a deformation behavior of a single-mirror holder (35) is determined, on which the single mirrors (18) are mounted. i ) of the single-mirror group are mounted. One of the single mirrors of the single-mirror group is designated as the measuring single mirror (43). Measuring light (50) is directed from a measuring light source (51) via a measuring reflective surface of the measuring single mirror (43) to a spatially resolved sensor (49) for measuring the actual orientation of the reflective surface of the measuring single mirror (43). The actual orientation of the reflective surface of the useful single mirror (18) to be measured i) is determined from the measured actual orientation of the reflective surface of the measuring single mirror (43) and the determined deformation behavior of the single mirror holder (35). This procedure is part of a correction procedure for the actual orientation of the reflective surface of the actuable useful single mirror (18). i The method is carried out using a measuring device (48) comprising at least one measuring mirror (43) and at least one spatially resolving sensor (49). The measuring method allows the reflective surface orientation of actuated tiltable single mirrors, which can be used in faceted mirror devices of corresponding lithographic projection exposure systems, to be specified and corrected with sufficient precision.

Description

[0001] The invention relates to a method for measuring an actual orientation of a reflection surface of an actuator-tiltable useful individual mirror of an individual mirror group of a facet mirror device. Furthermore, the invention relates to a method for correcting such an actual orientation, a measuring device for carrying out such a method, a correction device for carrying out such a method, an optical assembly with such a measuring device or with such a correction device, an illumination optics assembly with such an optical assembly, an optical system with such an illumination optics assembly, a projection exposure system with such an optical system, a manufacturing method for a micro- or nanostructured component using such a projection exposure system, and a micro- or nanostructured component manufactured using this method.

[0002] DE 10 2017 204 104 A1 discloses an EUV collector for use in an EUV projection exposure system. DE 10 2017 212 622 A1 discloses a measuring device for determining the spatial position of an illumination light beam path of an EUV projection exposure system. DE 10 2012 218 155 A1 discloses a device for coupling illumination radiation into an illumination optics system. US 8,958,053 B2 discloses a projection exposure system and an alignment method. US 2011 / 0122389 A1 discloses a light source, a projection exposure system, and a method for manufacturing a component.

[0003] It is an object of the present invention to provide a reflection surface orientation of actuator-tiltable individual mirrors, which can be used in facet mirror devices of corresponding lithographic projection exposure systems, with sufficient precision.

[0004] This object is achieved according to the invention by a measuring method having the features specified in claim 1.

[0005] The facet mirror device can be a facet mirror device of an illumination optics of a lithographic projection exposure system.

[0006] When used within such a facet mirror device, the useful individual mirror to be measured directs illuminating light towards an object field.

[0007] The useful individual mirror can be a field facet and / or a pupil facet. Examples of this are given in DE 10 2009 030 501 A1. The useful individual mirror can be a single mirror, particularly designed as a micromirror, wherein several such individual mirrors can be assigned to one another to form a useful individual mirror group, e.g., in the form of a field facet and / or a pupil facet. An illumination optics system that uses such individual mirrors can employ at least one MEMS facet mirror device.

[0008] The deformation behavior of the single mirror mount can be determined using at least one of the following measurement methods: - By means of a calibration measurement in which an actual orientation of the reflection surface of the individual measuring mirror is assigned to an actual orientation of the reflection surface of the individual useful mirror to be measured; - A simulation of the deformation behavior of the single mirror mount; - A calculation of the deformation behavior of the single mirror holder, for example in the form of a bending beam deformation, in particular by using numerical methods such as finite elements.

[0009] Within the scope of the measurement procedure, exactly one individual mirror from the individual mirror group can be specified as the individual measuring mirror. Alternatively, a plurality of the individual mirrors from the individual mirror group can be specified as individual measuring mirrors, for example, two or three individual mirrors.

[0010] An orientation measurement according to the specified method enables the monitoring of any tilt or deformation of the individual mirrors of the individual mirror group attached to the individual mirror holder.

[0011] The actual orientation of the reflective surface of the measured individual useful mirror can result from actuator forces, for example, from an individual mirror actuator, or from temperature changes in components of the facet mirror device. This can be caused, for example, by a thermal imbalance between individual useful mirrors exposed to illumination light and individual mirrors not exposed to the illumination light. Such a thermal imbalance can, in turn, cause thermal deformation of the individual mirror mount.

[0012] The orientation measurement of several individual useful mirrors of the individual mirror group according to claim 2 leads to a particularly meaningful measurement result. These multiple individual useful mirror orientations can be measured sequentially and / or in parallel. In particular, all individual useful mirrors of the individual mirror group can be measured with regard to their actual orientation.

[0013] A temperature detection system according to claim 3 also allows the measurement method to be thermally calibrated with respect to the temperature of the respective component being measured. This can be used as part of a temperature-dependent correction or compensation of the corresponding actual orientations of the individual mirrors being used.

[0014] A correction method according to claim 4 uses the result of the measurement method to improve the precision of a specification of an illumination light guide across the respective useful individual mirror. In particular, an illumination setting, i.e., an illumination angle distribution and / or illumination intensity distribution of the illumination light across the object field, can then be precisely specified. The correction method can be used to control the actual orientation of the reflection surface of the at least one useful individual mirror and, in particular, all useful individual mirrors of the respective individual mirror group.

[0015] A correction method with a basic adjustment according to claim 5 generates highly reproducible starting conditions, particularly for the correction method. The measurement method and / or the correction method can be carried out within the scope of such a basic adjustment. The specified reference force exerted by the individual mirror actuator on the individual mirrors can be a minimum force. Such a minimum force can be determined during a calibration measurement.

[0016] Alternatively, the reference force can be a specified fraction of the maximum force that the individual mirror actuator can exert on the individual mirrors, for example, half the maximum force. The maximum force can be determined during a calibration measurement.

[0017] A measuring device according to claim 6 has the advantages already explained above with reference to the measuring method on the one hand and the correction method on the other. With the aid of the spatially resolving sensor, the actual orientation of the individual measuring mirror can be measured with high precision. The spatially resolving sensor can be an array of sensor pixels. The spatially resolving sensor can be designed as a CMOS array, a CCD array, or even a PSD (position sensitive device) detector. A measuring light source for generating measuring light, which is detected by the spatially resolving sensor of the measuring device, can be a useful light source of the projection exposure system, of which the useful individual mirror is a component. Alternatively, the measuring device can also have a separate measuring light source. The facet mirror device usually has several individual mirror groups.In one variant, the facet mirror device can have exactly one individual mirror group.

[0018] In a further embodiment of the measuring device, an individual measuring mirror of the measuring device can also be assigned to several individual mirror groups, which are in particular operatively connected to one another.

[0019] The advantages of a correction device according to claim 7 correspond to those already explained above in connection with the correction method.

[0020] The advantages of an optical assembly according to claim 8, an illumination optics according to claim 9, an optical system according to claims 10 or 11, a projection exposure system according to claim 12, a manufacturing method according to claim 13, and a micro- or nanostructured component according to claim 14 correspond to those already explained above with reference to the measuring method, the correction method, and the measuring device. In particular, a highly integrated semiconductor component, for example a microchip, in particular a memory chip, can be manufactured using the method.

[0021] Embodiments of the invention are explained in more detail below with reference to the drawings, in which: Fig. 1 schematically shows a projection exposure system for EUV microlithography, with an illumination optics sectioned and a projection optics shown highly schematically; Fig. 2 a plan view of a field facet mirror of the illumination optics according to Fig. 1; Fig. 3 and Fig. 4 Top views of further versions of a field facet mirror of the illumination optics according to Fig. 1; Fig. 5 shows a perspective view of a further embodiment of the illumination optics of the projection exposure system; Fig. 6 shows, in a schematic cross-section, a facet module of the field facet mirror with a plurality of facets or a plurality of individual mirrors that can be grouped into facets, arranged on a mirror carrier of the field facet mirror, wherein the facet module and the mirror carrier can be used in the embodiments of the field facet mirror shown above; Fig. 7 a top view of the facet module according to Fig. 6, seen from view direction VII in Fig. 6; Fig. 8 compared to Fig. 6 shows, more schematically, the facet module in a side view, wherein a facet holder of the facet module is shown in various, exaggerated deflection situations; Fig. 9 in one to Fig. 8 similar representation, the facet module including a measuring device for carrying out a method for measuring an actual orientation of a reflection surface of an actuator-tiltable individual mirror, i.e. a field facet in the design of the field facet mirror according to the Fig. 2 to 4 or a single mirror in the design of the field facet mirror according to Fig. 5; Fig. 10 in a diagram cumulative actuator forces acting on an actuator for tilting the useful individual mirrors of the field facet mirror in different illumination settings adjustable with the illumination optics; and Fig. 11 in one to Fig. 10 comparable diagram, measured tilts of the reflection surface of a single measuring mirror of the measuring device in the lighting settings according to Fig. 10.

[0022] Fig. Figure 1 schematically shows a projection exposure system 1 for EUV microlithography. An EUV radiation source serves as the light source 2. This can be an LPP (laser-produced plasma) radiation source or a DPP (discharged-produced plasma) radiation source. A synchrotron or a free-electron laser (FEL) can also be used as a light source. The light source 2 emits useful EUV radiation 3 with a wavelength in the range between 5 nm and 30 nm. The useful radiation 3 is also referred to below as illumination or imaging light.

[0023] The illumination light 3 emitted by the light source is first collected by a collector 4. Depending on the type of light source 2, this can be an ellipsoidal mirror or a nested collector. After the collector 4, the illumination light 3 passes through an intermediate focus in an intermediate focal plane 5 and then strikes a field facet mirror 6. Exemplary embodiments of the field facet mirror 6 are explained below. The illumination light 3 is reflected by the field facet mirror 6 toward a pupil facet mirror 7. The illumination light beam is split into a plurality of illumination channels via the facets of the field facet mirror 6 on the one hand and the pupil facet mirror 7 on the other, with each illumination channel being assigned exactly one facet pair with a field facet and a pupil facet.The respective field facet and / or the respective pupil facet of one of the illumination channels can in turn be constructed from a group of individual mirrors assigned to this facet, as will also be explained below.

[0024] A follow-up optics unit 8 arranged downstream of the pupil facet mirror 7 guides the illumination light 3, i.e., the light from all illumination channels, to an object field 9. The field facet mirror 6, the pupil facet mirror 7, and the follow-up optics unit 8 are components of an illumination optics unit 10 for illuminating an illumination field that coincides with the object field 9 and is therefore also referred to below as the object field. The object field 9 lies in an object plane 11 of a projection optics unit 12 of the projection exposure system 1 arranged downstream of the illumination optics unit 10. The shape of the object field 9 depends on the design of the illumination optics unit 10 on the one hand and the projection optics unit 12 on the other hand, as explained below.

[0025] For the entire projection exposure system 1 according to Fig. 1 is a global Cartesian xyz coordinate system and in the Fig. 2 ff. a local Cartesian xyz coordinate system is used for individual components of the projection exposure system 1.

[0026] A structure arranged in the object field 9 on a reticle 12a, i.e., on a mask to be projected, is imaged by the projection optics 12, reduced by a reduction scale, onto an image field 13 in an image plane 14. The reticle 12a is supported by a reticle holder 12b.

[0027] The reduction scale of the projection optics is 12x4. Other reduction scales, such as 5x, 6x, 8x, or 10x, are also possible.

[0028] At the location of the image field 13, a wafer 13a is arranged, onto which the structure of the reticle is transferred for producing a micro- or nanostructured component, for example, a semiconductor chip. The wafer is supported by a wafer holder 13b. The reticle holder 13b can be displaced along the y-direction, also referred to as the object displacement direction, via a reticle displacement drive 12c. The wafer holder 13b can also be displaced along the y-direction via a wafer displacement drive 13c, synchronized with the reticle displacement drive 12c. Depending on the design of the projection exposure system 1 as a scanner or stepper, this displacement can occur continuously and / or stepwise.

[0029] The follow-up optics 8 between the pupil facet mirror 7 and the object field 9 has three additional EUV mirrors 15, 16, 17. The last EUV mirror 17 in front of the object field 9 is designed as a grazing incidence mirror. In alternative designs of the illumination optics 10, the follow-up optics 8 can also have more or fewer mirrors or even be omitted entirely. In the latter case, the illumination light 3 is guided from the pupil facet mirror 7 directly to the object field 9.

[0030] To facilitate the representation of positional relationships, an xyz coordinate system is used below. Fig. 1, the x-direction runs perpendicular to the plane of the drawing. The y-direction runs in the Fig. 1 to the right and the z-direction runs in the Fig. 1 down. As far as in the Fig. 2 ff., a local Cartesian coordinate system is used, this defines the reflection surface of the displayed component. The x-direction is then parallel to the x-direction in the Fig. 1. An angular relationship of the y-direction of the individual reflection surface to the y-direction in the Fig. 1 depends on the orientation of the respective reflecting surface.

[0031] Fig. 2 shows the field facet mirror 6 in more detail. The field facet mirror 6 according to Fig. 2 has a field facet arrangement with curved field facets 18. These field facets 18 are arranged in a total of five columns S1, S2, S3, S4 and S5, which are arranged in the Fig. 2 are numbered from left to right. In each of the five columns S1 to S5 there is a plurality of field facet groups 19, which are also referred to as field facet blocks or facet modules. The arrangement of the field facets 18 is determined by a mirror carrier in the form of a Fig. 2, the field facet mirror 6 is supported by a circular support plate 20. The field facet arrangement is inscribed in the circular boundary of the support plate 20. A normal to the support plate 20 runs perpendicular to the xy plane. A boundary of a far field of the illumination light 3 coincides with this circular boundary. The arcuate field facets 18 of the field facet mirror 6 according to Fig. 2 all have the same area and the same ratio of width in x-direction and height in y-direction, i.e. they all have the same xy aspect ratio.

[0032] One of the facet modules 19 is in the Fig. 2 is highlighted by a dashed line. Depending on the design of the field facet mirror 18, the facet modules 19 can each have the same number of field facets 18 or different numbers of field facets 18. A pupil facet of the pupil facet mirror 7 is assigned to each of the field facets 18 of the field facet mirror 6 via the respective illumination channel. Such a pupil facet can be designed as a monolithic facet or as a group of several individual mirrors.

[0033] Fig. 3 shows a further embodiment of the field facet mirror 6, which instead of the field facet mirror 6 according to Fig. 2 can be used in the projection exposure system 1. Components and functions corresponding to those described above with reference to the Fig. 1 and Fig. 2 have the same reference numbers and will not be discussed in detail again.

[0034] The field facet mirror 6 according to Fig. 3 has a total of four in columns S1, S2, S3, S4, which are in the Fig. 3 are numbered from left to right, arranged individual field facets 18. The two middle columns S2, S3 are separated from each other by a construction space 21, which runs in the y-direction and has a constant x-extension. The construction space 21, in turn, corresponds to a far-field shading of the illumination light beam, which is structurally determined by a corresponding design of the light source 2 and the collector 4. The four facet columns S1 to S4 each have a y-extension, which ensures that all four facet columns S1 to S4 lie within a circularly delimited far field 22 of the illumination light 3. The edge of the support plate 20 for the field facets 18 coincides with the edge of the far field 22.

[0035] The field facets 18 have a mutually congruent arc or partial ring shape with respect to a projection onto the xy plane, i.e. with respect to a main reflection plane of the field facet mirror 6, which corresponds to the shape with the field facet mirror according to Fig. 6 illuminable object field 9 can be similar.

[0036] The object field 9 (see also Fig. 5) has an x / y aspect ratio of 13 / 1. The x / y aspect ratio of the 18 field facets can be greater than 13 / 1. Depending on the design, the x / y aspect ratio of the 18 field facets is, for example, 26 / 1 and is usually greater than 20 / 1.

[0037] Overall, the field facet mirror has 6 Fig. 3 416 field facets 18. Alternative designs of such field facet mirrors 6, such as the field facet mirror 6 according to Fig. 2, the number of field facets 18 can range from a few tens to, for example, a thousand.

[0038] The field facets 18 of the field facet mirror 6 according to Fig. 3 have an extension in the y-direction of approximately 3.4 mm. The extension of the field facets 18 in the y-direction is in particular greater than 2 mm. The extension of the field facets 18 in the x-direction varies, so that some of the field facets 18 have a larger and some of the field facets 18 of the field facet mirror 6 according to figure a smaller x-extension. The field facets 18 of the field facet mirror 6 according to Fig. 3 thus differ in their projection onto an xy base plane of the field facet mirror in their size and, insofar as individual field facet pairs can be converted into each other by rotation about an axis parallel to the z-axis, in their orientation.

[0039] The projection surfaces of the reflection surfaces of at least two of the field facets 18 onto the base plane of the field facet mirror 6, thus also the xy-plane, differ due to their varying extension along the x-direction, also in the arc angle they sweep. In other words, not all of the field facets 18 of the field facet mirror 6 have Fig. 3 the same azimuthal extent of their arc curvature.

[0040] The total of all 416 field facets 18 of the field facet mirror 6 according to Fig. 3 has a packing density of 73%. The packing density is defined as the sum of the area of ​​all field facets 18 relative to the total illuminated area on the carrier plate 20.

[0041] Along the columns Si, the arrangement of the field facets 18 of the field facet mirror 6 is Fig. 3 is again divided into several facet modules 19, which in the Fig. 3 is not shown.

[0042] Configurations of the field facet mirror 6 are also possible in which the projections of the reflection surfaces of at least two of the field facets 18 onto the xy base plane differ in shape. For example, field facets 18 with different y-extensions can be used.

[0043] Fig. Figure 4 shows a further embodiment of a field facet mirror which can be used instead of the field facet mirror 6 in the illumination optics 10. Components and functions which correspond to those described above with reference to the Fig. 1 to 3 have already been explained, have the same reference numbers and will not be discussed in detail again.

[0044] The field facet mirror 6 according to Fig. 4 differs from the field facet mirror 6 according to the Fig. 2 and Fig. 3 in the shape and arrangement of the field facets 18. The field facets 18 are rectangular and each have the same x / y aspect ratio, which corresponds to the aspect ratio of the field facets 18 according to the Fig. 2 and Fig. 3. The field facets 18 according to Fig. 4 define a reflection surface of the field facet mirror 6 and are grouped into four columns S1, S2, S3 and S4. Within the columns S1 to S4, the field facets 18 are again divided into field facet modules 19 according to Fig. 2. Between the two middle facet columns S2, S3 and between centrally arranged facet rows, the facet arrangement of the field facet mirror 6 has Fig. 4 spaces 23 in which no facets are arranged, since these areas of the far field of the light source 2 are shaded by holding spokes of a correspondingly shaped collector 4.

[0045] Fig. Figure 5 shows a schematic and perspective arrangement of a further embodiment of a field facet mirror 24 on the one hand and a pupil facet mirror 25 on the other hand. The field facet mirror 24 according to Fig. 5 can be used instead of the field facet mirrors explained above. Components and functions corresponding to those described above with reference to the Fig. 1 to 4 have already been explained, have the same reference numbers and will not be discussed in detail again.

[0046] Fig. 5 schematically illustrates a beam path of the illumination light 3 along an illumination channel 31 from an intermediate focus IF in the intermediate focal plane 5 to the object field 9. Associated with this illumination channel 31 are a field facet 261 of the field facet mirror 24 and a pupil facet 271 of the pupil facet mirror 25. The field facet 261 is constructed from a group of 18 individual mirrors ES with an overall arcuate envelope similar to the object field 9. The grouping of the individual mirrors ES into the field facet 261 can be dependent on an illumination angle distribution for the object field 9, which can be set via the illumination optics with the facet mirrors 24, 25, i.e., dependent on an illumination setting of the illumination optics 10.

[0047] Via the actuator-adjustable tilt angles of the individual mirrors ES, four individual mirrors ES of the pupil facet mirror 25 are assigned to the field facet 261 via the illumination channel 31, which, in the form of a 2 x 2 array, form the pupil facet 271 of the pupil facet mirror 25. Via a corresponding actuator-based tilt setting, which in turn is dependent on the illumination setting, the individual mirrors ES of this pupil facet 271 are preset such that the object field 9 is illuminated via the illumination channel 31.

[0048] Accordingly, the Fig. 5 on the field facet mirror 24, a further facet 262 and a further facet 272, which belong to a corresponding, further illumination channel 32. By superimposing the illumination channels 3 i on the object field 9, a grouping of individual mirrors to the field facets 26 is created i and the pupil facets 27 idependent illumination angle distribution and illumination intensity distribution on the object field 9, i.e., the respective illumination setting. This illumination setting can be specified such that the same illumination angle distribution is present on the object field 9 regardless of the field. Alternatively, a field-dependent illumination setting can be specified, in which different illumination angle distributions are defined across the object field. A specified illumination intensity distribution across the object field 9 can also be achieved by appropriately assigning the field facets 26. i to the pupil facets 27 i via corresponding illumination channels 3 i be specified.

[0049] The two facet mirrors 24 and 25 can be constructed in the same way, particularly in the manner of MEMS mirrors, and each have a plurality of individual mirrors ES. These individual mirrors ES are in turn grouped into modules, which, in terms of their basic structure, correspond to the facet modules 19 of the previously explained embodiments of the field facet mirror 6. In the following description of such a module, a module having a plurality of field facets is described; accordingly, such a module can also have a plurality of individual mirrors ES or even a plurality of monolithic pupil facets of a corresponding pupil facet mirror.

[0050] Fig. Figure 6 schematically shows a cross-sectional view of an embodiment of the facet module 19. The facet module 19 is supported by the mirror carrier 20 via a corresponding bearing with bearing points 31, 32. The mirror carrier 20 supports a plurality of such facet modules 19, as already explained above. Since the facet modules 19 are constructed similarly, it is sufficient to describe one of these facet modules 19 below.

[0051] The facet module 19 has an actuator module 33 for the actuator tilting of the individual mirrors of the facet module 19, which, according to the above explanations, can be monolithic field facets in the type of the field facets 18, monolithic pupil facets or also individual mirrors ES.

[0052] The following description refers to the variants in which the individual mirrors are field facets 18. In the same way, actuator-based tilting of monolithic pupil facets or individual mirrors can be achieved. These monolithic field facets, monolithic pupil facets, and individual mirrors are collectively referred to below as the individual useful mirrors of the respective facet mirror device.

[0053] Shown in the Fig. 6 three actuator-tiltable field facets 181, 182 and 183. These are each connected via a joint connection 34 i held on a single mirror holder 35 of the actuator module 33.

[0054] The single mirror holder 35 is designed as a holding plate with a through-opening at the location of the joint connection 34 i The single-mirror mount 35 is mounted on a housing 38 of the actuator module 33 via bearing points 36, 37.

[0055] Via a respective facet or mirror pin 39 i is a basic body of the respective field facet 18 i with an actuator permanent magnet 40 i firmly connected. About the facet pin 39 i In addition, the respective field facet 18 is connected i at the joint 34 i .

[0056] The actuator permanent magnets 40 i are the respective actuator electromagnets 41 i which are housed in the housing 38 of the actuator module 33.

[0057] By controlling and supplying the actuator electromagnets 41 i the actuator permanent magnets 40 i the respective field facets 18 i be deflected independently of each other, as in the Fig. 6 is indicated by a double arrow 42 for the field facet 181. Tilting of the field facet 181 by a tilt angle drx about a tilt axis parallel to the x-axis and by a tilt angle dry about a tilt axis parallel to the y-axis can be independently controlled. In this way, the respective field facet 18 i via the respective illumination channel 3 i one of the pupil facets of the pupil facet mirror 7 to specify the respective illumination setting. Similarly, if instead of the field facets 18 i Individual mirrors ES are attached, can be used by appropriately controlled independent tilting of the individual mirrors ES instead of the field facets 18 i Grouping assignments of these individual mirrors ES to the field facets 26 i and if necessary to the pupil facets 27 i for specifying illumination channels 3 i after Fig. 5 can be specified.

[0058] Fig. 7 shows an embodiment of the facet module 19 and the actuator module 33 with a total of twelve field facets 18, which in a variant of the field facet mirror 6 according to Fig. 2 can be used.

[0059] Eleven of the twelve field facets 18 are individual useful mirrors for specifying corresponding illumination channels 3 i A twelfth facet, which is Fig. 7 is highlighted at the very top, represents a single measuring mirror 43 of a measuring device which will be explained below.

[0060] Fig. 8 shows the facet module 19 in a Fig. 6 similar representation, where the individual useful individual mirrors, for example the field facets 18 i in the Fig. 8 are not shown in detail. Illustrated in the Fig. 8 two different deflection situations of the holding plate of the single mirror holder 35. The dashed line shows Fig. 8 a position situation 44 of the single mirror holder 35 which is not bent between the bearing points 36 and 37. The solid line in the Fig. 8 a bent position situation 45 of the single mirror holder 35 between the bearing points 36, 37. Such a bent position situation can arise in particular due to accumulated actuator forces which the actuator electromagnets 41 of the actuator module 33 exert on the field facets 18 i Depending on the actuator principle used, corresponding actuator forces can also arise in other ways, for example, in the form of capacitive actuator forces or in the form of non-contact actuator forces. Actuator variants that can be used are known, for example, from DE 10 2012 224 022 A1 and US 10,303,065 B2.

[0061] Fig. 8 further illustrates a change in directions of reference normals 46 on the holding plate of the single-mirror holder 35 due to the respective positional situations 44 and 45. The reference normals 46 in the non-bent positional situation 44 are shown in dashed lines and the reference normals 47 in the bent positional situation 45 are shown in solid lines.

[0062] Due to the deflection of the individual mirror mount 35 in the deflected position 45, a significant deviation between the directions of the reference normals 46, 47 arises at the location of the corresponding useful individual mirror held by the individual mirror mount 35, particularly in the outer edge area of ​​the individual mirror mount 45 adjacent to the outer bearing points 36, 37. Due to this deflection, an actual tilt angle of the respective useful individual mirror is influenced by a corresponding change in direction.

[0063] As the Fig. As illustrated in Figure 8, this difference ΔR of the directions between the normals 46 and 47 depends on the y-coordinate of a position of the respective useful individual mirror, for example, the respective field facet 181, on the individual mirror mount 35. A corresponding dependency also arises along the x-coordinate. The respective reference normals at the location of the measuring individual mirror 43 are highlighted by an index M, whose position on the facet module 19 is selected such that the sensitivity of the normal tilt ΔR to the deflection of the individual mirror mount 35 is as high as possible there.

[0064] Fig. Figure 9 illustrates details of a measuring device 48, to which the measuring individual mirror 43 belongs. Components and functions corresponding to those described above with reference to the Fig. 1 to 8 and in particular with reference to the Fig. 7 and Fig. 8 have already been explained, have the same reference numbers and will not be discussed in detail again.

[0065] In addition to the individual measuring mirror 43, the measuring device 48 also includes a spatially resolving sensor 49, which can be implemented as a CMOS or CCD sensor pixel array or as a PSD detector. The spatially resolving sensor 49 is arranged in a measuring light beam path of measuring light 50, which is guided over the individual measuring mirror 43. The measuring light 50 can be the illumination light 3. The measuring light beam path is shown starting from the intermediate focus IF of the illumination light 3 in the intermediate focal plane 5.

[0066] Alternatively, the measuring device 48 can also have a measuring light source 51 separate from the light source, which is shown in the Fig. 9 is also illustrated very schematically.

[0067] A position of an impact point A of the measuring light 50 on the spatially resolving sensor 49 is a measure of the directional difference ΔR (x, y) at the location of the measuring individual mirror 43 and thus a measure of a deformation, in particular of a deflection of the individual mirror holder 35 due to accumulated actuator forces, which lead to tilting of the useful individual mirrors, thus in particular to the field facets 18 i via the actuator module 33.

[0068] The measuring device 48 is part of a correction device 52, which additionally includes a control / regulating device 53, which is in signal connection with the actuator module 33, which in the Fig. 9 is not shown in detail.

[0069] The measuring device 48 can in principle also have at least one temperature sensor 54.

[0070] The field facet mirror 6, the pupil facet mirror 7, the field facet mirror 24 and the pupil facet mirror 25 are examples of a facet mirror device of an optical assembly to which the measuring device 48 and the correction device 52 belong.

[0071] Fig. 10 shows values ​​of a cumulative actuation force F on the useful individual mirrors of each facet module 19, for example on the field facets 18 i of the facet module 19 to Fig. 6, as a function of a respective illumination setting BS. Illumination settings BS that can be used here include, for example, an annular illumination setting, a dipole illumination setting (x-dipole, y-dipole), or a multipole illumination setting. A conventional illumination setting, in which a uniform illumination angle distribution is achieved within certain illumination angle limits, can also be used. Depending on the illumination setting BS, the field facets 18 i of the facet module 19 are tilted to varying degrees, resulting in a correspondingly different force effect that the actuator module 33 exerts via the actuator electromagnets 41 on the actuator permanent magnets 40 and, via these, on the individual mirror holder 35. The cumulative force F can vary by several orders of magnitude depending on the illumination setting BS.

[0072] Fig. 11 shows a dependence of a displacement ΔA of the point of impact A on the spatially resolving sensor 49 of the measuring device 48, again on the respective illumination setting BS, whereby these illumination settings BS are plotted in the same sequence as in the Fig. 10. A very clear correlation results between the cumulative force F for the respective illumination setting BS and the impact location offset ΔA. After a corresponding calibration, an impact location offset ΔA and thus a change in direction ΔR of a reference normal and thus a tilt change of the individual measuring mirror 43 can be predicted for the respective illumination setting BS, which can be used to correct tilt angle offsets of the individual useful mirrors 18 i or ES of the respective facet module 19 can be used.

[0073] An actual orientation of a reflection surface of the field facet mirror 182, i.e. an example of an actuator-tiltable useful individual mirror of an individual mirror group of such a facet mirror device, can be measured using the measuring device 48 as follows: Initially, the measurement procedure determines the deformation behavior of the individual mirror mount 35. This can be done by analytically simulating the deformation behavior of the individual mirror mount 35 and / or by finite element calculation and / or by simulating the deformation behavior.

[0074] To prepare the measuring procedure, one of the individual mirrors of the individual mirror group, i.e. in the example described above one of the field facets 18 iof the facet module 19 is specified as the individual measuring mirror 43. A plurality of corresponding individual measuring mirrors 43 can also be specified and used in the further measuring process for measuring light guidance and measuring light detection.

[0075] The measuring light 50 is then guided from a measuring light source, which can be the light source 2 or the separate measuring light source 51, via a measuring reflection surface of the individual measuring mirror 43 to the spatially resolving sensor 49 for measuring a corresponding actual orientation of the measuring reflection surface of the individual measuring mirror 43.

[0076] From the measured actual orientation of the measuring reflection surface of the measuring individual mirror 43 and the determined deformation behavior, the actual orientations of the other reflection surfaces of the useful individual mirrors 18 can then be determined. i of the facet module 19.

[0077] The deformation behavior of the individual mirror holder 35 can also be determined by a calibration measurement in which an actual orientation of the reflection surface of the useful individual mirror to be measured is assigned to a respective actual orientation of a measuring reflection surface of the measuring individual mirror 43.

[0078] By means of the temperature sensor 54 of the measuring device 48, a temperature of the individual mirror holder 35 and / or the measuring individual mirror 43 and / or at least one of the useful individual mirrors 18 i of the facet module 19 and assigned to a measured actual orientation of the individual measuring mirror 43. This allows the temperature influence on the specified tilt angles of the individual useful mirrors to be reduced and, if necessary, even completely eliminated.

[0079] The measuring method can be part of a method for correcting an actual orientation of a reflection surface of the actuatable useful individual mirror 18 ior ES of the facet module 19. First, a target orientation of the corresponding reflection surface of the useful individual mirror 18 i or ES. After carrying out the described measurement procedure, a comparison of the determined actual orientation of the reflection surface of the useful individual mirror 18 i or ES with the specified target orientation. Depending on the comparison result, the actuators of the useful individual mirror 18 can then i or ES can be controlled to approximate the actual orientation to the target orientation as soon as the comparison shows that an orientation difference between the target orientation and the actual orientation is greater than a specified tolerance value.

[0080] To prepare the correction procedure, a basic adjustment of the respective facet mirror device 6, 7, 24, 25 can be carried out, in which an initial actual orientation of the individual useful mirrors 18i or ES is controlled by an actuator at an illumination angle distribution in which a single mirror actuator, averaged over the useful individual mirrors 18 i or ES of this facet mirror device, and in particular of a considered facet module of the facet mirror device, exerts a minimal force on the individual useful mirrors. Such a basic adjustment with the lowest cumulative actuator force on the individual useful mirrors reduces disruptive actuator influences on the initial tilt position of the individual useful mirrors.

[0081] After carrying out the orientation correction process in particular, a micro- or nanostructured component can be manufactured by means of the projection exposure system 1.

[0082] To produce a micro- or nanostructured component, the projection exposure system 1 is used as follows: First, the reticle and the wafer are prepared. A structure on the reticle is then projected onto a light-sensitive layer of the wafer using the projection exposure system 1. By developing the light-sensitive layer, a microstructure is then created on the wafer, thus creating the microstructured component.

[0083] The projection exposure system 1 is designed as a scanner. The reticle is continuously displaced in the y-direction during the projection exposure. Alternatively, a stepper design is also possible, in which the reticle is displaced stepwise in the y-direction.

[0084] If the projection exposure system 1 is designed as a scanner, the scanning direction y runs parallel to the transverse dimension x of the object field 9. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 204 104 A1

[0002] DE 10 2017 212 622 A1

[0002] DE 10 2012 218 155 A1

[0002] US 8,958,053 B2

[0002] US 2011 / 0122389 A1

[0002] DE 10 2009 030 501 A1

[0007] DE 10 2012 224 022 A1

[0060] US 10,303,065 B2

[0060]

Claims

[1] Method for measuring the actual orientation of a reflection surface of an actuator-tiltable single mirror (18 i ; ES) of a single mirror group of a facet mirror device (6; 7; 24; 25), wherein the individual mirrors (18 i ; ES) of the single mirror group are mounted on a common single mirror holder (35) with the following steps: - Determining a deformation behavior of the single mirror holder (35), - specifying at least one of the individual mirrors of the individual mirror group as the measuring individual mirror (43), - guiding measuring light (50) from a measuring light source (2; 51) via a measuring reflection surface of the individual measuring mirror (43) to a spatially resolving sensor (49) for measuring an actual orientation of the reflection surface of the individual measuring mirror (43), - Determine the actual orientation of the reflection surface of the useful individual mirror to be measured (18 i; ES) from the measured actual orientation of the reflection surface of the individual measuring mirror (43) and the determined deformation behavior. [2] Method according to claim 1, characterized by that the actual orientation of several useful individual mirrors (18 i ; ES) of the individual mirror group is determined from the measured actual orientation of the reflection surface of the individual measuring mirror (43). [3] Method according to claim 1 or 2, characterized by that a temperature of the individual mirror holder (35) and / or the measuring individual mirror (43) and / or at least one of the useful individual mirrors (18 i ; ES) of the individual mirror group is recorded and assigned to the measured actual orientation of the individual measuring mirror (43). [4] Method for correcting an actual orientation of a reflection surface of an actuatable useful individual mirror (18 i ; ES) of a single mirror group of a facet mirror device (6; 7; 24; 25), with the following steps: - Specification of a target orientation of the reflection surface of the useful individual mirror (18 i ; ES), - Carrying out the method according to one of claims 1 to 3, - Comparison of the determined actual orientation of the reflection surface of the useful single mirror (18 i ; ES) with the specified target orientation, - Control of an actuator (41 i ) of the useful single mirror (18 i ; ES) to approximate the actual orientation to the target orientation as soon as the comparison shows that an orientation difference between the target orientation and the actual orientation is greater than a specified tolerance value. [5] Correction method according to claim 4 when using the facet mirror device (6; 7; 24; 25) in an illumination optics (10), in which by actuator tilting of the useful individual mirrors (18 i; ES) different illumination angle distributions of an illumination of an object field (9) by the illumination optics (10) can be specified, wherein for a basic adjustment of the facet mirror device (6; 7; 24; 25) an initial actual orientation of the useful individual mirrors (8 i ; ES) is controlled by an actuator at an illumination angle distribution in which a single mirror actuator (41 i ) averaged over the useful individual mirrors (18 i ; ES) of the facet mirror device (6; 7; 24; 25) integrally applies a predetermined reference force to the useful individual mirrors (18 i ; ES). [6] Measuring device (48) for carrying out a method according to one of claims 1 to 5, - with at least one measuring individual mirror (43) as a component of an individual mirror group on a facet mirror device (6; 7; 24; 25), wherein at least one useful individual mirror (18 i ; ES) belongs, - with at least one spatially resolving sensor (49), arranged in a measuring light beam path which is guided over the individual measuring mirror (43). [7] Correction device for carrying out a method according to one of claims 4 or 5, - with a measuring device (48) according to claim 6, - with a control / regulating device (53) which is connected to an actuator (41 i ) for tilting the at least one useful individual mirror (18 i ; ES) and is in signal connection with the spatially resolving sensor (49). [8] Optical assembly with a measuring device (48) according to claim 6 or with a correction device (53) according to claim 7, - with a facet mirror device (6; 7; 24; 25), - with an actuator (41 i ) for tilting the at least one useful individual mirror (18 i; ES), which is in signal connection with the control / regulating device (53) of the measuring device (48) or the correction device (52). [9] Illumination optics (10) with an optical assembly according to claim 8, for illuminating an object field (9), in which an object (12a) to be imaged can be arranged, with illuminating light (3). [10] Optical system with an illumination optics according to claim 9 and with a projection optics (12) for imaging the object field (9) into an image field (13) in which a substrate (13a) can be arranged. [11] Optical system with an illumination optics according to claim 9 and with a light source (2) for generating the illumination light (3). [12] Projection exposure apparatus with an optical system according to claim 10 and / or 11. [13] Method for producing a structured component with the following process steps: - Providing a reticle and a wafer as a substrate, - Projecting a structure on the reticle onto a light-sensitive layer of the wafer using the projection exposure apparatus (1) according to claim 12, - Creating a micro- and / or nanostructure on the wafer. [14] Structured component produced by a method according to claim 13.

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