Optical system for projection exposure apparatus and method for specifying illumination pupil

Abstract

An optical system for a projection exposure apparatus has an illumination optical unit for guiding illumination and imaging light (3) from a light source to an object field in which an object to be imaged can be arranged, and an imaging optical unit for imaging the object field to an image field in which a substrate to be exposed can be arranged. The imaging optical unit has an exit pupil (36) with at least one obscured exit pupil region (38) located in an outer pupil edge (37). The illumination optical unit is designed in such a way that an illumination angle distribution occurs when the object field is illuminated with the illumination and imaging light (3) and can be described by means of an illumination pupil (12a), the illumination pupil region (I) illuminated by the illumination light being adapted to a shielded exit pupil region (38) of the imaging optical unit. A shielded exit pupil region (38) of the imaging optical unit may have a non-central geometric center of mass (SP). In a variation of the optical system, the illumination optical unit is embodied such that an illumination angle distribution occurs in the object field and can be described by an illumination pupil (12a) having an obscured illumination pupil region (31), the envelope of which deviates from a circle in pupil coordinates (sigma x, sigma y) normalized with respect to an outer pupil edge (37) and / or in absolute pupil coordinates (rhox, rhoy). In order to specify the illumination pupil (12a), the diffractive behavior of at least one object structure of the object to be imaged is analyzed, the position of the occluded exit pupil region (38) in the exit pupil (36) is detected, and the illumination pupil (12a) is adjusted such that at least one variation of the optical system occurs. This improves the resolution of the optical system.

Description

An optical system for a projection exposure device and a method for specifying an illumination pupil.

[0001] The contents of German patent application DE 10 2023 209 698.6 are incorporated herein by reference. Technical Field

[0002] This invention relates to an optical system for a projection exposure apparatus. Furthermore, this invention relates to a projection exposure apparatus having such an optical system, a method for specifying an illumination pupil of an illumination optical unit having a suitable illumination pupil to produce such an optical system, a method for producing microstructures or nanostructures using such a projection exposure apparatus, and microstructures or nanostructures produced according to this method. Background Technology

[0003] Optical systems of the type described at the beginning have been disclosed in WO 2012 / 028303 A1, US 10,139,734 B2, US10,254,653 B2, DE 10 2021 200 114 A1 and US 9,720,329 B2. The following details reveal imaging optics units that may be applicable to photolithographic projection exposure equipment: Levinson et al.'s article "Lithographic pattern formation in the presence of aberrations in anamorphic optical systems" in Proc. of SPIE Vol. 113231132230A-1, 2020; de Winter et al.'s article "Extreme ultraviolet scanner with high numerical aperture: obscuration and wavefront description" in J. Micro / Nanopattern. Mater. Metrol. 023801-2, 2022; and de Winter et al.'s article "High NA EUV scanner: obscuration and wavefront description" in Proc. of SPIE Vol. 11517 1151715-1, 2020. The journal articles “High NA EUV lithography: Next step in EUV imaging” published by Setten et al. in Proc. of SPIE Vol. 10957 1095709-01, 2019; “Physical dose modeling and throughput optimization in EUV computational lithography” published by Peng et al. in Proc. of SPIE Vol. 12494 124940C-1, 2023; and Maguire et al. in Proc. of SPIE Vol.The journal articles "Defining Tatian-Zernike polynomials for use in a lithography simulator" (12494, 124940P-1, 2023), "Computational lithography solutions to support EUV high-NA patterning" (Zhao et al., Proc. of SPIE Vol. 12495, 124950R-1, 2023), "High-NA EUV lithography exposure tool: program progress" (van Schoot et al., Proc. of SPIE Vol. 11323, 1132307-1, 2023), and "High-NA EUV lithography exposure tool: program progress" (Wischmeier et al., Proc. of SPIE Vol. 11323, 1132308-1, 2023) are mentioned. The journal articles published in 2020 include "High-NA EUV lithography optics becomes reality" (Vol. 11517, 1151712-1), "High-NA EUV lithography exposure tool: advantages and program progress" (Vol. 1151712-1), and "Computational evaluation of critical logical metal layers of pitch 20-24 nm and the aberration sensitivity in high NA EUV single patterning" (Vol. 12495, 1249509-1), by van Schoot et al., and Gao et al., "Computational evaluation of critical logical metal layers of pitch 20-24 nm and the aberration sensitivity in high NA EUV single patterning" (Vol. 1249512-249509-1), by Gao et al., in which Gao et al. published their work in 2023. Summary of the Invention

[0004] The problem to be solved by this invention is to improve the resolution of the type of optical system proposed at the beginning.

[0005] According to the present invention, this problem is solved by an optical system having the features specified in claim 1 and an optical system having the features specified in claim 2.

[0006] According to the present invention, it is recognized that adapting the illumination pupil of the illumination optical unit in an optical system to the exit pupil of the imaging optical unit in the optical system provides the possibility of further improving the imaging behavior of the optical system, thereby increasing its resolution. Therefore, this creates the possibility of using a projection exposure device to image the corresponding object to be imaged onto a substrate (particularly in the form of a wafer) at a higher resolution.

[0007] In particular, it has been shown that adapting the illumination pupil to the area of ​​the exit pupil of the imaging optics is especially useful. By adapting the illumination pupil to the area of ​​the exit pupil, illumination light that can be effectively used for high-resolution imaging is provided.

[0008] In particular, in this context, a masking illumination pupil region with a non-central geometric centroid can also be provided, that is, a masking illumination pupil region with an equilibrium point not located at the center of the exit pupil.

[0009] An illumination pupil may contain at least one illumination electrode. An illumination pupil may contain at least two illumination electrodes. An illumination pupil may contain exactly one, two, three, four, five, six, seven, eight, nine, or ten illumination electrodes. An illumination pupil may also contain more than ten illumination electrodes.

[0010] The illumination pole is an illumination pupil region, which is describably defined by its envelope and illuminated by illumination light. Generally speaking, the illumination pole can be illuminated by illumination light without gaps, or the illumination pole can have an incident position distribution of illumination channels specified by the illumination optics unit.

[0011] According to claim 1, the corresponding advantages are particularly effective when adapting to the shielded exit pupil region having a non-central geometric centroid. This adaptation is achieved through the appropriate specifications of the illumination pupil, with particular consideration given to those illumination pupil regions that interact with the shielded exit pupil region of the imaging optics. In this case, diffraction of the illumination pupil at the structure of the object to be imaged can be particularly considered.

[0012] The shielded illumination pupil region of claim 2 provides additional degrees of freedom when adapting the illumination pupil to the shielded exit pupil of the imaging optics unit.

[0013] The exit pupil to be adapted may have an outer boundary and / or a boundary that obscures the exit pupil region, which is circular in normalized and / or absolute pupil coordinates, or deviates from a circle, for example, having an ellipse.

[0014] Therefore, the illumination pupil adapted to it may also have an outer boundary and / or a boundary for the occlusion illumination pupil region, which is circular in normalized and / or absolute pupil coordinates, or deviates from a circle, for example, having an ellipse. Especially in the case of deformable imaging optics, the occlusion exit pupil region of the imaging optics may be circular, while the occlusion illumination pupil region has an envelope that deviates from a circle.

[0015] The illumination pupil of claim 3 takes into account the shielding of the exit pupil region, so that the zero-order illumination light is not unnecessarily blocked at the shielding point of the imaging optics. This results in a corresponding increase in luminous flux.

[0016] The illumination pupil of claim 4 takes into account the fact that the diffracted imaging light within the exit pupil will not unintentionally diffract into the region that blocks the exit pupil. In this case, a corresponding diffraction direction can be considered, which depends on the alignment of the object structure to be imaged. Multiple diffraction directions can also be considered when designing an illumination pupil adapted to the exit pupil.

[0017] In the case of the illumination pupil according to claim 5, in any case, there is illumination from an illumination pupil adjacent to the region of the shielding illumination pupil, which is adapted to the region of the shielding exit pupil. In this case, an illumination pupil with a high integrated luminous flux can be provided. When specifying such an illumination pupil, diffraction effects in at least one diffraction direction can also be considered. For example, an illumination pupil can be specified such that the diffracted illumination light is not undesirably blocked in the region of the shielding exit pupil.

[0018] In any case, the illumination pupil according to claim 6 may provide a dark-field illumination component, wherein the zero-order diffracted illumination light does not reach the image field but is blocked at the shield and / or the outer edge of the exit pupil. In addition to such a dark-field illumination component, the illumination pupil may also provide another illumination component, wherein the zero-order diffracted illumination light also reaches the image field.

[0019] The illumination pupil according to claim 7 can provide swamped illumination that also includes an illumination component in the illumination pupil region, in which imaging light of the zeroth order diffraction can also reach the image field in addition to dark field illumination.

[0020] According to claim 8, an illumination pupil having an illumination pupil untouched by illumination light produces an illumination pupil that takes into account tolerances for the orientation of the obscured exit pupil region, particularly drift tolerances or other field-dependent tolerances. Slight pupil displacement will not cause the illumination pupil region to be located within the obscured exit pupil region before the displacement undesirably occurs, and vice versa. Tolerances of the imaging optics, particularly the obscured exit pupil region, and tolerances of the illumination optics, particularly the obscured illumination pupil region, can be taken into account. Typically, tolerances in the illumination light guidance (i.e., the illumination beam path) and the imaging beam path can be taken into account.

[0021] The range around the illumination pupil (i.e., the distance between areas of the adaptive illumination pupil illuminated by the illumination light) along the coordinates of the corresponding edge segment perpendicular to the edge of the area of ​​the occluded exit pupil can be between 0.1% and 5% of the entire pupil range.

[0022] Overall, dark-field illumination can be provided by using the illumination pupil according to claim 9; this provides a special resolution advantage for certain imaging tasks.

[0023] With the adapted illumination pupil according to claim 10, the diffraction effect and / or field correlation effect of the exit pupil can be considered, especially if the illumination pupil itself does not have a field correlation embodiment.

[0024] The field-correlated illumination pupil of claim 11 has a particular advantage in terms of flexibility. The field dependence of the illumination pupil can be used to ensure adaptation to the corresponding field-correlated exit pupil. However, alternatively or additionally, the field dependence of the illumination pupil can also be used to adapt to field-correlated diffraction behavior variations in the structure of the object to be imaged.

[0025] The illumination pupil according to claim 12 provides corresponding advantages.

[0026] The edge profile parameters according to claim 13 produce a particularly effective illumination pupil adaptation. The eccentricity of the edge profile of the occluded exit pupil region can range from 0.004 to 0.02, from 0.005 to 0.01, and for example from 0.006 to 0.007. The average deviation of the edge profile of the occluded exit pupil region from a circle can range from 0.125 to 0.275, particularly from 0.15 to 0.275.

[0027] According to claim 14, the illumination optical unit may be equipped with a field plane mirror and a pupil plane mirror; this has proven its value in practice. Alternatively, the illumination optical unit may, for example, include a field plane mirror and another plane mirror disposed at a certain distance from the pupil plane of the illumination optical unit. Such a concept is referred to as a specular reflector in the prior art.

[0028] The illumination optics unit of claim 15 may be equipped with a faceted mirror, which provides multiple individual transmission mirror groups and / or individual illumination specification mirror groups to designate corresponding illumination channels. Such a faceted mirror may be in the form of a MEMS mirror.

[0029] The light source of the optical system according to claim 16 can be an EUV light source or a DUV light source. The wavelength range of EUV illumination light is between 5 nm and 30 nm, for example, about 13.5 nm. The wavelength of DUV illumination light can be 193 nm or longer.

[0030] The advantages of the projection exposure apparatus according to claim 17 correspond to the advantages of the optical system of the present invention already explained above.

[0031] Another problem solved by this invention is a method for matching a specified illumination pupil, which can improve the resolution of an optical system.

[0032] According to the present invention, this problem is solved by a specification method having the method steps of claim 18.

[0033] The specification method considers both the object's diffraction behavior and the function of blocking the exit pupil region. This leads to corresponding optimized illumination.

[0034] The method of claim 19 takes into account the field dependence of the exit pupil of the imaging optics unit and / or the field correlation of object diffraction, which can lead to additional resolution advantages in illumination and / or illumination / imaging flux advantages within the optical system.

[0035] The advantages of the manufacturing method according to claim 20 and the microstructure or nanostructure component according to claim 21 correspond to those advantages explained above with reference to the illumination optics unit. The manufactured component can be a semiconductor element, particularly a microchip, especially a memory chip. Attached Figure Description

[0036] Exemplary embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings, in which:

[0037] Figure 1 schematically shows a projection exposure apparatus for EUV microlithography in a meridional cross section, which has a light source, an illumination optics unit and a projection optics unit, wherein the inset shows a plan view of the object field of the projection exposure apparatus.

[0038] Figure 2 schematically and similarly shows in meridional cross-section the beam paths of selected individual rays of illumination light within the illumination optics unit according to Figure 1, which travel from the central focal point to a mask master or object in the object plane of the projection optics unit disposed in the illumination area or object field.

[0039] Figure 3 shows a plan view of the first faceted mirror of the illumination optical unit, which is arranged in the field plane of the illumination optical unit and in the illumination far field of the light source, and is also called the field faceted mirror. The array configuration of the individual mirror units is shown, which in each case is formed by a sub-array of individual mirrors of the first faceted mirror (not shown in Figure 1).

[0040] Figure 4 still schematically shows, but in a magnified, exemplary and more detailed manner than Figure 3, one of the individual mirror units implemented as an individual mirror subarray;

[0041] Figure 5 shows a plan view of the illumination specification faceted reflector of the illumination optical unit, which is positioned at a certain distance from the pupil plane of the illumination optical unit and is also called the second faceted reflector.

[0042] Figure 6 again schematically illustrates an embodiment of the illumination optics unit of the projection exposure apparatus, which has two faceted mirrors implemented as MEMS mirrors with multiple individual mirrors, wherein the second faceted mirror again serves as an illumination specification faceted mirror, which is disposed at a certain distance from the pupil plane of the illumination optics unit, and wherein the two illumination channels of the illumination optics unit are highlighted by example for superimposing illumination on the mask master at a defined illumination angle distribution, and wherein selected individual rays for illuminating the object field from three different directions (two pupil edge rays and one main ray) are further illustrated;

[0043] Figure 7 shows the illumination pupil area of ​​the illumination optical unit adapted to the illumination exit pupil area of ​​the projection optical unit of the projection exposure device, wherein this shows the illumination of the illumination pupil within the illumination pupil area by illumination light and via multiple illumination channels indicated by the corresponding illumination intensity contour lines in Figure 7.

[0044] Figure 8 shows an embodiment of an adapted illumination pupil for an illumination optics unit in a schematic similar to Figure 7. The illumination optics unit has an inner shielding illumination pupil region (which is adapted to a shielding exit pupil region of a projection optics unit) and an outer illumination pupil region surrounding this shielding illumination pupil region. The area around the illumination pupil (again illustrated by individual illumination channels) located between the shielding illumination pupil region and the outer illumination pupil region and including a designated area of ​​the exit pupil of the projection optics unit adjacent to the edge of the shielding exit pupil region is not illuminated by illumination light.

[0045] Figures 9A / 9B schematically show two variations of the adapted illumination pupil with dark field illumination, i.e., when the illumination light shines on the mask master from an angle not located within the exit pupil of the projection optics unit.

[0046] Figures 10 to 12 show embodiments of the adapted illumination pupil, in which the shielding illumination pupil area corresponding to the shielding exit pupil area of ​​the projection optical unit is not illuminated by the illumination light;

[0047] Figure 13 shows the illumination pupil. In this case, the shielded illumination pupil area, which is adapted to the shielded exit pupil area of ​​the imaging optical unit, is fully illuminated, resulting in dark field illumination as shown in Figure 9A.

[0048] Figure 14 shows a similar illustration to Figure 13 of the adapted illumination optical unit. In this case, the illumination pupil is not additionally illuminated by illumination light within the illumination pupil coordinate range of the cross-diffraction pupil coordinates perpendicular to the diffraction pupil coordinates. The illumination pupil coordinate range corresponds to the range of the shielded exit pupil region along this cross-diffraction pupil coordinate. However, in the four illumination pupil regions outside the shielded illumination pupil region, the illumination pupil is illuminated outside this illumination pupil coordinate range of the cross-diffraction pupil coordinates.

[0049] Figure 15 shows an embodiment of an adapted illumination pupil with a completely submerged occluded illumination pupil area, similar to Figure 13.

[0050] Figure 16 shows a similar illustration to Figure 15, in which the illumination pupil area is not illuminated by illumination light in a manner similar to Figure 8, around an area of ​​the illumination pupil corresponding to an area of ​​the exit pupil adjacent to the edge of the blocking exit pupil area.

[0051] Figure 17 shows an embodiment of an adapted illumination pupil with a shielded illumination pupil region, similar to Figures 10 to 16, wherein the shielded illumination pupil region is illuminated by illumination light, such that a segment in the diffraction pupil region of the exit pupil appears outside the exit pupil in the shielded illumination pupil region without illumination.

[0052] Figure 18 shows a variation of the illumination in the masked illumination pupil region, similar to Figure 17, such that there is no illumination in the masked illumination pupil region that results in overlap with the diffraction pupil region in the exit pupil;

[0053] Figures 19 to 21 show adapted dark-field illumination pupils similar to those in Figure 13, although the outer envelope of the occluded illumination pupil region deviates from an ellipse. The dark-field illumination pupils are plotted for three different field heights, particularly at the minimum field height coordinate (Figure 19), at the central field height coordinate (Figure 20), and at the maximum field height coordinate (Figure 21). The illumination field dependence of the dark-field illumination pupil follows the exit pupil field dependence of the exit pupil.

[0054] Figures 22 to 24 show, in a similar manner to Figures 19 to 21, a further embodiment of an illumination pupil region adapted to a shielded exit pupil region (located within the shielded exit pupil region), wherein, in this case, the illumination angle distribution of the adapted illumination pupil is not field-dependent, but the exit pupil of the projection optics unit is field-dependent.

[0055] Figure 25 shows an embodiment of the adapted illumination pupil, similar to that in Figure 13, which is configured as the distribution of the illumination channel by the illumination optics unit, wherein the first faceted mirror is implemented as a field faceted mirror and the second faceted mirror is implemented as a pupil faceted mirror, illustrated in normalized pupil coordinates (which represent a measure of the maximum possible illumination angle in the radial direction within the pupil in each case).

[0056] Figure 26 shows the illumination pupil according to Figure 25, plotted in absolute, non-normalized pupil coordinates (which represent a measure of the actual illumination angle);

[0057] Figure 27 shows, in a similar manner to Figure 25, an adapted illumination pupil according to Figure 11, which has a centrally located shielded illumination pupil area, again set by an illumination optical unit having a field plane mirror and a pupil plane mirror.

[0058] Figure 28 shows the illumination pupil according to Figure 27 in terms of absolute pupil coordinates corresponding to Figure 26;

[0059] Figure 29 shows an embodiment of an adapted illumination pupil corresponding to Figure 25, which has a shielded illumination pupil region that is not illuminated by illumination light, and the shielded illumination pupil region is adapted to shield the exit pupil region, wherein the illumination pupil is illuminated only in the pupil region adjacent to the edge of the shielded exit pupil region.

[0060] Figure 30 shows the illumination pupil according to Figure 29 in terms of absolute pupil coordinates corresponding to Figure 26;

[0061] Figure 31 shows a similar illustration to Figure 25 of the adapted illumination pupil of Figure 16, which is again set by an illumination optics unit having a field plane mirror and a pupil plane mirror.

[0062] Figure 32 shows the illumination pupil according to Figure 31 in terms of absolute pupil coordinates corresponding to Figure 26;

[0063] Figure 33 shows an embodiment of the adapted illumination pupil in a diagram similar to that of Figure 25, which represents the superposition of the pupil according to Figure 25 and the x-dipole illumination pupil, having two pupil stripes that are fully illuminated on the pupil along the cross-diffraction pupil coordinates.

[0064] Figure 34 shows the illumination pupil according to Figure 33 in terms of absolute pupil coordinates corresponding to Figure 26;

[0065] Figure 35 shows an embodiment of the illumination pupil according to Figure 14, which is set by an illumination optical unit having a field plane mirror and a pupil plane mirror;

[0066] Figure 36 shows the illumination pupil according to Figure 35 in terms of absolute pupil coordinates corresponding to Figure 26;

[0067] Figure 37 shows an embodiment of the adapted illumination pupil in a similar diagram to Figure 35, which again has an illuminated shielding illumination pupil region corresponding to the shielding exit pupil region, and other illumination pupil regions in the form of four illumination poles, wherein the illumination pupil is not illuminated by illumination light within the illumination pupil coordinate range along the diffraction pupil coordinates, wherein this unilluminated illumination pupil coordinate range corresponds to the range of the shielding exit pupil region along the diffraction pupil coordinates in Figure 14;

[0068] Figure 38 shows the illumination pupil according to Figure 37 in terms of absolute pupil coordinates corresponding to Figure 26;

[0069] Figure 39 shows another embodiment of the adapted illumination pupil, similar to Figures 33 to 38, which can be set by an illumination optical unit having a field plane mirror and a pupil plane mirror, wherein the illumination pupil represents the superposition of the illuminated shielding illumination pupil area (which corresponds to the shielding exit pupil area) and the quadrupole illumination pupil.

[0070] Figure 40 shows the illumination pupil according to Figure 39 in terms of absolute pupil coordinates corresponding to Figure 26;

[0071] Figure 41 shows an adapted illumination pupil in a similar diagram to Figure 39, which again has an illuminated shielded illumination pupil area adapted to the shielded exit pupil area of ​​the projection optical unit, and has a total of eight mutually separated illuminated illumination pupil areas, which are in the form of illumination poles outside the shielded illumination pupil areas.

[0072] Figure 42 shows the illumination pupil according to Figure 41 in terms of absolute pupil coordinates corresponding to Figure 26;

[0073] Figure 43 shows the adapted target illumination pupil of the pattern in Figure 29, which has a stadium-shaped masking illumination pupil area and uniform illumination between the inner edge and the outer boundary;

[0074] Figure 44 shows the actual illumination pupil corresponding to Figure 43, which is set by the mirror reflector design of the illumination optics unit according to Figure 6;

[0075] Figure 45 schematically shows an embodiment of a mask master to be illuminated in a plan view, which has regions with fine mask master structures and regions with coarse mask master structures;

[0076] Figure 46 shows an embodiment of an adapted illumination pupil corresponding to Figure 10, for a finer mask master structure based on the mask master of Figure 45;

[0077] Figure 47 shows an embodiment of the adapted illumination pupil, similar to that in Figure 46, for use with the coarse mask master structure of Figure 45 and for the mask master structure transition region between the fine and coarse mask master structures.

[0078] Figure 48 shows a total of four variations of the edge profile of the adapted shielding illumination pupil region, which adapt to a given shape of the shielding exit pupil region of the projection optics unit; and

[0079] Figure 49 shows four variations of the edge profile of the adapted shielding illumination pupil region, similar to Figure 48, and another variation adapted to the shape of the shielding exit pupil region of the projection optics unit. Detailed Implementation

[0080] The microlithography projection exposure apparatus 1, schematically shown at meridional profile height in Figure 1, has a light source 2 for illumination and imaging light 3. The light source 2 is an EUV light source that produces light with wavelengths ranging from 5 nm to 30 nm. Here, this can be an LPP (laser-generated plasma) light source, a DPP (discharge-generated plasma) light source, or a synchrotron radiation-based light source, such as a free-electron laser (FEL).

[0081] The transmission optical unit 4 is used to guide the illumination light 3 originating from the light source 2. The transmission optical unit 4 has a light collector 5 and a transmission surface-mount mirror 6, where the light collector 5 is only shown for its reflection effect in Figure 1, while the transmission surface-mount mirror 6 will be described in more detail below and is also referred to as the first surface-mount mirror or field surface-mount mirror. The intermediate focal point 5a of the illumination light 3 is disposed between the light collector 5 and the transmission surface-mount mirror 6. For example, the numerical aperture of the illumination light 3 in the region of the intermediate focal point 5a is NA = 0.182. The illumination specification surface-mount mirror 7 (also referred to as the second or another surface-mount mirror and will also be explained in detail below) is disposed downstream of the transmission surface-mount mirror 6, and therefore also downstream of the transmission optical unit 4. Optical components 5 to 7 are part of the illumination optical unit 11 of the projection exposure apparatus 1.

[0082] In one embodiment of the illumination optical unit 11, a transmission faceted mirror 6 is disposed in the field plane of the illumination optical unit 11. The first faceted mirror 6 is configured to be disposed in the far-field use region of the light source 2.

[0083] In one embodiment of the illumination optical unit 11, the illumination specification faceted mirror 7 of the illumination optical unit 11 is disposed at a certain distance from the pupil plane of the illumination optical unit 11. This configuration is also referred to as a specular reflector. Alternatively, the illumination specification faceted mirror 7 may also be disposed in the region of the pupil plane of the illumination optical unit 11, and in this case it is referred to as a pupil faceted mirror.

[0084] The mask master 12 is positioned downstream of the illumination specification faceted reflector 7 in the beam path of the illumination light 3, and is disposed in the object plane 9 of the downstream projection optical unit 10 of the projection exposure device 1. The projection optical unit 10 is a projection lens. The projection optical unit 10 is also referred to below as the imaging optical unit.

[0085] The illumination optics unit 11 is used to illuminate the object field 8 on the mask master 12 in the object plane 9 in a defined manner. Simultaneously, the object field 8 constitutes the illumination field of the illumination optics unit 11. Generally, the illumination field is formed such that the object field 8 can be positioned within the illumination field.

[0086] Similar to the transmission faceted mirror 6, the illumination specification faceted mirror 7 is part of the pupil illumination unit of the illumination optics unit and is used to illuminate the entrance pupil 12a in the pupil plane 12b of the projection optics unit 10 with illumination light 3 having a specific pupil intensity distribution. The entrance pupil 12a also constitutes the illumination pupil of the illumination optics unit 11. The entrance pupil 12a of the projection optics unit 10 can be configured upstream or downstream of the object field 8 in the illumination beam path.

[0087] In the embodiment according to FIG. 1, the illumination optics unit 11 has exactly two mirrors for guiding the illumination light 3 downstream of the light collector 5, specifically two faceted mirrors 6 and 7. Depending on the embodiment of the illumination optics unit 11, these two mirrors 6 and 7 may also be supplemented by other mirrors for guiding the illumination light 3 between the collector 5 and the object field 8, such as at least one deflecting mirror between the light collector 5 and the first faceted mirror 6, and / or at least one deflecting mirror between the two faceted mirrors 6 and 7, and / or at least one deflecting mirror between the second faceted mirror 7 and the object field 8.

[0088] Figure 1 shows the case where the incident pupil 12a is positioned in the illumination beam path downstream of the object field 8. In this case, the pupil distance PA between the second faceted mirror 7 and the pupil plane 12b is the sum of the z-distance PA1 between the second faceted mirror 7 and the object plane 9 and the z-distance PA2 between the object plane 9 and the pupil plane 12b. Therefore, the following applies: PA = PA1 + PA2. Alternatively, the pupil distance PA can also be measured in the beam direction.

[0089] The illumination pupil area of ​​the illumination pupil 12a illuminated by the illumination light 3 is adapted to the exit pupil of the projection optical unit 10, as described below.

[0090] For ease of representation of positional relationships, the Cartesian xyz coordinate system will be used below. The x-direction is perpendicular to and enters the drawing plane of Figure 1. In Figure 1, the y-direction extends to the right. The z-direction extends downwards in Figure 1. In each case, the coordinate system used in the figures has x-axes that are parallel to each other. The z-axis of this coordinate system follows the corresponding principal direction of the illumination light 3 in the corresponding diagram under consideration.

[0091] The object field 8 has an arcuate or partially circular shape and is defined by two parallel arcs and two straight side edges extending in the y-direction for a length of y0 and spaced x0 apart in the x-direction. The aspect ratio x0 / y0 is 13:1. The inset in Figure 1 shows a plan view of the object field 8, which is not drawn to scale. The boundary shape 8a is arcuate. In an alternative and equally possible object field 8, its boundary shape is rectangular, also with an aspect ratio x0 / y0.

[0092] During the projection exposure, the mask master 12 is displaced in the object displacement direction y through the object field 8.

[0093] Figure 1 shows only a portion of the projection optics unit 10 schematically. The object-side numerical aperture 13 and image-side numerical aperture 14 of the projection optics unit 10 are shown. The image-side numerical aperture 14 can be in the range of 0.2 to 0.7, and can be, for example, 0.3, 0.33, 0.4, 0.45, 0.5, 0.55, or 0.6. Between the shown optical components 15 and 16 of the projection optics unit 10 (which can be, for example, implemented as mirrors reflecting EUV illumination light 3), the projection optics unit 10 also provides other optical components (not shown in Figure 1) for guiding the illumination light 3 between these optical components 15 and 16. The projection optics unit 10 is implemented as a masking imaging optics unit. The projection optics unit 10 has a last mirror located in the beam path of the illumination and imaging light 3, which has a channel opening for the illumination and imaging light 3. The reflective surface of this last mirror of the projection optics unit 10 is interrupted in the region of this channel opening, resulting in masking. The exit pupil of the projection optical unit 10 therefore has a shielded exit pupil area. The edge contour of the shielded exit pupil area of ​​the projection optical unit 10 can be specified for the illumination and imaging light 3 by means of the shielding aperture in the beam path of the projection optical unit 10.

[0094] The projection optics unit 10 images the object field 8 into an image field 17 in an image plane 18 on a wafer 19, which, like the mask master 12, is held by a holder (not shown in detail). Both the mask master holder and the wafer holder can be displaced in the x and y directions by corresponding displacement actuators. The mounting space requirement for the wafer holder is shown as a rectangular box 20 in Figure 1. The mounting space requirement 20 is a cuboid, and its extent in the x, y, and z directions depends on the components to be housed therein. For example, the mounting space requirement 20 extends 1 m from the center of the image field 17 in the x and y directions. In the z direction, the mounting space requirement 20 also extends, for example, 1 m from the image plane 18. The illumination light 3 must be guided in the illumination optics unit 11 and the projection optics unit 10 such that it is guided through the mounting space requirement 20 in each case.

[0095] The transmission surfaced mirror 6 has multiple transmission surfaces 21, which may also be referred to as the first surface. The transmission surfaced mirror 6 can be implemented as a MEMS mirror. Each transmission surface 21 has multiple individual mirrors ES (also refer to Figures 4 and 6), which can switch between at least two tilt positions and are implemented as micromirrors. The individual mirrors ES can be implemented as micromirrors capable of tilting about two mutually perpendicular rotation axes in a driven manner.

[0096] In the transmission surface 21, a row with a total of nine transmission surfaces 21 is schematically shown in the yz cross-sectional view according to Figure 2, which are labeled 211 to 219 from left to right in Figure 2. In fact, the transmission surface mirror 6 has significantly more transmission surfaces 21. The individual mirrors ES of the transmission surface mirror 6 are grouped into multiple transmission surfaces 21. These transmission surfaces 21 are also referred to as individual mirror groups, virtual field surfaces, or virtual surface groups. An individual mirror group is a group of individual mirrors ES of the first surface mirror 6 that are imaged into the object field 8 through the same second surface 25.

[0097] Each transmission plane 21 guides a component of the illumination light 3 (also called the illumination light component beam) via the illumination channel to partially or completely illuminate the object field 8. This illumination channel and the illumination light component beam 3 guided by it... i In each case, exactly one illumination specification plane 25 of the illumination specification plane mirror 7 is assigned to one of the individual mirror groups or the transmission plane group. In principle, each illumination specification plane 25 may be composed of multiple individual mirrors in sequence. The illumination specification plane 25 is also referred to as the second plane hereinafter. When the second plane mirror 7 is arranged in the region of the pupil plane of the illumination optical unit 11, the illumination specification plane 25 is also referred to as the pupil plane.

[0098] For further details regarding possible embodiments of the transmission faceted reflector 6 and the projection optical unit 10, please refer to WO2010 / 099 807 A.

[0099] At least some of the illumination specification facets 25 illuminate only a portion of the object field 8 or a portion of the field. The shape of this portion of the field is highly unique and depends on the desired illumination direction distribution (pupil shape) in the object field 8, i.e., the illumination setting. Therefore, the illumination specification facets 25 are illuminated by virtual field facets with very different shapes, the shapes of which precisely correspond to the shapes of the corresponding portions of the field to be illuminated. Furthermore, each illumination specification facet 25 contributes to different regions of the pupil based on its position in the object field 8.

[0100] The illumination specification facet 7 can be implemented as a MEMS mirror, particularly when each illumination specification facet 25 is composed of multiple individual mirrors ES (refer to Figure 6). The illumination specification facet 25 is a micromirror that can switch between at least two tilt positions. The illumination specification facet 25 is implemented as a micromirror that can be continuously and independently tilted about two mutually perpendicular tilt axes in a driven manner, that is, the micromirror can be positioned at multiple different tilt positions.

[0101] Figure 2 illustrates an example of the designated allocation of individual transmission facets 21 to lighting specification facets 25. In each case, the lighting specification facets 25 allocated to transmission facets 211 through 219 are indicated according to this allocation. Due to this allocation, the lighting specification facets 25 are illuminated from left to right in the following order: 256, 258, 253, 254, 251, 257, 255, 252, and 259.

[0102] Indices 6, 8, and 3 of planes 21 and 25 contain three illumination channels VU, VIII, and III, which illuminate three object points OF1, OF2, and OF3 from the first illumination direction. These object points are numbered from left to right in Figure 2. Indices 4, 1, and 7 of planes 21 and 25 belong to three additional illumination channels IV, I, and VII, which illuminate three object points OF1 to OF3 from the second illumination direction. Indices 5, 2, and 9 of planes 21 and 25 belong to three additional illumination channels V, II, and IX, which illuminate three object points OF1 to OF3 from the third illumination direction. Illumination channels I to IX are assigned corresponding illumination light components 31 to 39.

[0103] The following lighting directions are assigned in all cases:

[0104] -Lighting channels VI, VIII, III

[0105] -Lighting channels IV, I, VII and

[0106] - Illumination channels V, II, IX

[0107] Therefore, the allocation of the transmission plane 21 to the illumination specification plane 25 results in telecentric illumination of the object field 8 in the case of the illumination example illustrated in the diagram.

[0108] The object field 8 can be illuminated via a specular reflector type transmission faceted reflector 6 and an illumination type faceted reflector 7. The principle of the specular reflector has been disclosed in US 2006 / 0132747 A1.

[0109] Figure 3 shows a plan view of the first faceted mirror 6. The first faceted mirror 6 has a regular array configuration of individual mirror units 26, which is defined by the square in Figure 3. Each individual mirror unit 26 is implemented as a subarray of N x M individual mirrors ES (refer to Figure 4). This subarray has multiple array rows extending along the row direction corresponding to the angle bisector of the xy coordinate system. Some mutually adjacent array rows are offset from each other by a proportion of the range of one of the individual mirror units 26, specifically by half of the range of the corresponding individual mirror unit 26 along the array row. According to the embodiment of the faceted mirror 6, it can be managed without any such offset, and thus this results in an array configuration constructed entirely of rows and columns. Alternatively, all array rows may be offset from each other. Depending on the embodiment of the faceted mirror 6 and depending on the requirements for the positioning of the individual mirror units 26, different absolute offset values ​​between different adjacent array portions are possible.

[0110] Figure 4 schematically, but in more detail, shows one of the individual mirror units 26. It shows an individual mirror unit 26 subdivided into 6×6 individual mirror ES subarrays in this case. Therefore, in the illustrated embodiment, each individual mirror unit 26 has 36 individual mirror ES. Thus, N = 6 and M = 6 are suitable for the N×M subarray configuration according to the example in Figure 4. N and M can be the same, can be different, and can each be in the range of 2 to 64, for example, 4, 8, 16, 32, or 64. Other values ​​for N and M besides powers of 2 are also possible, such as 25 or 50. For example, 12 x 12 or 24 x 24 subarrays are also possible.

[0111] In the embodiment shown in FIG3, the first faceted mirror 6 has an arrangement of individual mirror units 26 within a circular envelope. Alternatively, the first faceted mirror 6 may also include individual mirror units 26 located within an envelope having elliptical, rectangular, or polygonal boundaries.

[0112] In each case, one of the individual mirror units 26 may comprise multiple complete or partial groups of individual mirrors that guide the illumination light 3 to different second facets 25 and image it onto the object field 8 in a superimposed manner. The groups of individual mirrors may extend over multiple individual mirror units 26.

[0113] Figure 5 then shows a plan view of the second faceted reflector 7.

[0114] The second facet 25 of the second facet mirror 7 is implemented with a circular boundary and exists in a hexagonal close-packed form. A second facet 25 with a rectangular or polygonal boundary, particularly a hexagonal boundary, is also an alternative to a second facet 25 with a circular boundary. The second facet 25 can also be implemented as an individual mirror unit in the style of an individual mirror unit of the first facet mirror 6, and in this case, it can be subdivided into multiple individual mirrors in the style of an individual mirror ES. In principle, regarding the division into individual mirrors and individual mirror units, the structure of the second facet mirror 7 can correspond to the structure of the first facet mirror 6.

[0115] In the embodiment according to FIG5, each of the second facets 25 can also be implemented as a single facet.

[0116] In the second faceted reflector 7, the second facet 25 is disposed within an envelope with an elliptical boundary. Alternatively, other envelope shapes are also possible, such as a circular envelope, a rectangular envelope, and an envelope with a polygonal boundary.

[0117] Figure 6 again schematically shows an embodiment of the illumination optical unit 11, wherein the first faceted mirror 6 is disposed in the region of the field plane of the illumination optical unit 11, and the second faceted mirror 7 is disposed at a certain distance from the pupil plane of the illumination optical unit 11, particularly at a certain distance from the pupil plane 12b (see also Figure 1).

[0118] Both faceted mirrors 6 and 7 are implemented as MEMS mirrors and contain multiple individual mirrors ES.

[0119] Figure 6 illustrates the selected individual ray beam paths between the intermediate focal point 5a and the entrance pupil 12a. Specifically, Figure 6 illustrates the routes of the two illumination channels 271, 272, guided by the transmission surfaces 211, 212 of the first faceted mirror 6 and the illumination specification surfaces 251, 252 of the second faceted mirror 7, respectively. Each transmission surface 21i is constructed as a 7 x 14 array of individual mirrors ES, with the longer portion of this array extending along the x-direction and the shorter portion extending along the y-direction, adapted to the aspect ratio of the object field 8.

[0120] For illustrative purposes, the two faceted mirrors 6 and 7 shown in Figure 6 are rotated 90° about the x-axis, so they are visible in the xy-plane view, while other components (such as the mask master 12 and the incident pupil 12a) are shown in the xz-meridian section.

[0121] Each lighting channel 27 i Lighting specifications are divided into 25 sections. i The implementation is a 2 x 2 array of individual reflectors ES of the faceted reflector 7 for illumination specifications.

[0122] In addition to the two illumination channels 27 between the central focal point 5a and the entrance pupil 12a i In addition to the main path, Figure 6 also shows the paths of individual rays assigned to different illumination angles. In this case, the main ray 28 (each passing through the center of the entrance pupil 12a) and the edge or coma rays 29 and 30 (defining the entrance pupil 12a on one side and the other side in the x-coordinate direction) are shown.

[0123] The illumination channel 271 is first defined by one of the main rays 28 and secondly by one of the edge rays 30, that is, in the illustrated configuration, it covers a portion of the entire entrance pupil 12a illuminated by the illumination pupil 11.

[0124] The illumination channel 272 is first defined by one of the main rays 28 and secondly by one of the edge rays 29, that is, it covers the range of complementary illumination angles within the entrance pupil 12a.

[0125] Two lighting channels, 271 and 272, illuminate the entire object field 8.

[0126] Alternatively, lighting channel 27 may also be used. i It is not the entire object field 8 that is illuminated, but only a portion of the field, and / or not a part of the incident pupil 12a, but the entire incident pupil 12a that is illuminated.

[0127] Figure 7 shows the shielding illumination pupil region 31 inside an embodiment of the illumination pupil 12a, whose edge region is not shown in Figure 7. In terms of its edge profile, the envelope 32 of the shielding illumination pupil region 31 conforms to the edge profile of an embodiment of the projection optical unit 10 corresponding to the shielding exit pupil region. The envelope 32 defines the core portion of the illumination pupil 12a, in which an illumination channel 27 for channel-by-channel mixed illumination is provided. i Incident position 33 i These incident positions are specified by the faceted reflectors 6 and 7 of the illumination optics unit 11. These incident positions 33 i Also known as a light spot. Incident position 33 iThe illumination intensity distribution is shown by the contour lines in Figure 7. The illumination intensity at incident position 33... i The intensity increases from the inside out, but the maximum value of the illumination intensity is not located at the center of the corresponding incident position 33i, but rather regularly deviates from the center. Incident position 33 i It is usually oval or circular. Different, less regular shapes may also occur. At incident position 33... i In addition, the area 31 of the occluded illumination pupils will not be illuminated by the illumination light 3, or will not be significantly illuminated, even within the envelope 32. The distribution of the areas of each illumination pupil 12a illuminated by the illumination light 3 is also referred to as the illumination setting.

[0128] In order to specify the illumination pupil 12a with the occluded illumination pupil region 31 according to Figure 7, which belongs to illumination channel 27 i and incident position 33 i First facet 21 i The tilt angle of each individual reflector ES is set such that the incident position 33 within the envelope 32 is... i It has the most uniform distribution possible and fills the entire masking illumination pupil area 31.

[0129] Therefore, in the absolute pupil coordinates ρ, which represent the absolute illumination angles of their respective regions... x ρ y In this context, the envelope 32 itself has an elliptical shape, that is, it deviates from a circle. The envelope 32 may also deviate from a circle in different ways.

[0130] Figure 8 shows another embodiment of the illumination pupil 12a, wherein the incident position 33i is configured to be distributed within the outer envelope 34 of the outer illumination pupil region 35 of the illumination pupil 12a. The outer envelope 34 is located at absolute pupil coordinates ρ. x ρ y The center is a circle, where the absolute pupil coordinates ρ x ρ y This represents a measurement of the illumination angle at the assigned object field point in object field 8. The external illumination pupil region 35 is located between the envelope 32 of the occluded illumination pupil region 31 on one hand and the outer envelope 34 on the other.

[0131] The envelope 32 of the shielding illumination pupil region 31 (which is similar to the illumination pupil 12a in FIG. 7 and is adapted to the shielding exit pupil region of the projection optical unit 10) is located within the circular outer envelope 34. Illumination channel 27 i Incident position 33 i This distribution within the outer envelope 34 ensures that all incident positions 33i have a minimum distance Δ from the envelope 32 of the occluded illumination pupil region 31. This minimum distance Δ can be determined relative to the pupil coordinate σ. x σ yThe coordinates are within 0.1% to 5% of the typical diameter of the shaded illumination pupil region 31, and in each case these coordinates have been normalized to the maximum illumination angle.

[0132] Therefore, around the illumination pupil surrounding the envelope 32, that is, around the illumination pupil corresponding to the region of the projection optical unit 10 at the edge of the adjacent shielding emission pupil region, the illumination light 3 will not illuminate either the inner shielding illumination pupil region 31 or the outer illumination pupil region 35.

[0133] The illumination pupil 12a is not illuminated by the illumination light 3 between the outer envelope 34 and the outer edge of the entire illumination pupil 12a, as not shown in FIG8. In the alternative illumination pupil 12a according to FIG8, the outer envelope 34 and the outer edge of the entire illumination pupil 12a coincide.

[0134] In the following text, Figures 9A and 9B are used to explain different variations of dark-field illumination, which can be appropriately selected by the illumination optics unit 11 through the individual mirrors ES of the faceted mirrors 6 and 7 by appropriately tilting them. i To make the settings.

[0135] Figure 9A shows the pupil of the projection exposure device 1, which can be understood as both the illumination pupil 12a and the exit pupil 36 of the projection optics unit 10. This pupil 12a, 36 has an outer pupil boundary 37, which specifies the numerical aperture of the corresponding optical units 11, 10 of the projection exposure device 1. In the case of the illumination pupil 12a of the illumination optics unit 11, the outer pupil edge 37 specifies the maximum possible illumination angle of the object field 8 in the direction of the corresponding pupil radius. In the case of the exit pupil 36 of the projection optics unit 10, the outer pupil edge 37 specifies the image field-side numerical aperture. Furthermore, the pupil edge 37 is regularly specified by the aperture stop of the projection exposure device 1. In the case of the pupils 12a, 36 shown in Figure 9A, the outer pupil edge 37 is circular, but it can also have any other shape of boundary, such as elliptical or otherwise deviating from a circular shape.

[0136] Furthermore, the exit pupil 36 has a shielded exit pupil region 38. This region is regularly defined by the shielding aperture of the projection exposure device 1, such that the channel opening in the last mirror of the projection optical unit 10 is, in particular, not illuminated by the illumination and imaging light 3. The shielded exit pupil region 38 has an elliptical boundary. In terms of its arrangement and shape, this boundary corresponds to the envelope 32 of the shielded illumination pupil region 31 according to Figures 7 and 8.

[0137] Figure 9A shows the incident position of the illumination light 33 at the center of the illumination pupil 12a. z Its standardized pupil coordinate σ x σ yThis indicates that the central incident position is 33. z Located at the center of the region 38 that blocks the outgoing pupil.

[0138] Use lighting channel 27 z Incident position 33 from illumination pupil 12a z Illuminating the object field 8 and the structured mask master 12 in the direction of illumination will produce B+ and B- order diffraction in the exit pupil 36. These B+ and B- order diffractions are located between the envelope of the shielding aperture region 38 and the outer pupil edge 37 of the exit pupil 36. Thus, this is an example of dark-field illumination, in which the zero-order illumination light 3 does not reach the image field 17, but is incident on the shielding aperture of the projection optics unit 10, while the illumination light of the B+ and B- order diffracted passes through the shielding aperture and aperture stop of the projection optics unit 10 and reaches the image field 17 for imaging the corresponding structure of the mask master 12 on the wafer 19.

[0139] Along the pupil coordinate σ x (Hereinafter referred to as the diffraction pupil coordinates of the outgoing pupil 36), the structure on the mask master 12 causes the imaging light 3 to diffract downstream of the mask master 12. The diffraction path d, i.e., the incident position 33 where B+ and B- order diffraction occurs on one side and zero-order diffraction on the other, is also present. z The distance between them, along the coordinates σ of this diffraction pupil x extend.

[0140] Figure 9B shows another variant of dark-field illumination. In this case, the incident position 330 of the zeroth-order diffraction of the imaging light 3 is located on the structure of the mask 12 outside the outer pupil edge 37 of the exit pupil 36, i.e., it is blocked by the aperture stop of the projection optical unit 10. Along the diffraction pupil coordinate σ x With diffraction paths d spaced apart, the B1 and B2 orders of the imaging light 3 diffracted at the structure of the mask master 12 appear within the outer pupil edge 37 of the exit pupil 36, and then reach the image field 17 for imaging the corresponding structure of the mask master 12 on the wafer 19. The exit pupil 36 according to FIG9B can be an unshielded exit pupil or a shielded exit pupil; this is not shown in detail in FIG9B.

[0141] As described above in conjunction with Figures 9A and 9B, the corresponding dark-field illumination can, in principle, be combined with the illumination setting variants explained herein, by appropriately setting the individual mirrors ES of the faceted reflectors 6 and 7 of the illumination optics unit 11. In the case of dark-field illumination according to Figure 9B, the individual mirrors ES on the illumination-specific faceted reflector 7 (which belong to the illumination angle beyond the outer pupil edge 37 of the exit pupil 36) are used to specify the incident position 330.

[0142] Figure 10 shows another embodiment of the adapted illumination pupil 12a illuminated by the illumination light 3. Components and functions that have been explained above with reference to Figures 1 to 9, and especially to Figures 7 to 9, have the same reference numerals and will not be discussed in detail again.

[0143] According to FIG10, the illumination pupil 12a is not illuminated by the illumination light 3 within the envelope 32 of the shielding illumination pupil region 31. Therefore, in the illumination pupil region corresponding to the shielding exit pupil region of the projection optical unit 10 (see 38 in FIG9A), the illumination pupil 12a according to FIG10 is not illuminated by the illumination light 3. In the representation according to FIG10, the envelope 32 is a horizontal ellipse and is centered about the outer pupil edge 37 of the illumination pupil 12a.

[0144] According to Figure 10, the illumination pupil 12a is illuminated by illumination light 3 in four strip-shaped pupil regions I1, I2, I3, and I4, which are located in one of the four quadrants Q1, Q2, Q3, and Q4 of the illumination pupil 12a, respectively. In principle, the illumination pupil 12a according to Figure 10 thus represents a quadrupole illumination setting with four illumination poles I1 to I4. The illumination pupil 12a according to Figure 10 is perpendicular to the diffraction pupil coordinate σ. x The cross-diffraction pupil coordinates σ y The range of illumination pupil coordinates Δσ y The area inside is not illuminated by illumination light 3. The coordinate range of this illumination pupil is Δσ. y Corresponding to the shading aperture region 38 along this cross diffraction pupil coordinate σ y The range is shown in Figure 10. Within this illumination pupil coordinate range, Δσ... y In this process, the lighting strips formed by the lighting electrodes I2, I3 and I1, I4 will be interrupted under various conditions.

[0145] According to the illumination settings 12a in Figure 10, this configuration of illumination poles I1 to I4 ensures that the diffraction pupil coordinates σ along the exit pupil 36 are... x The diffraction orders will not reach the masking aperture region 38 because, in this case, they would adversely fail to contribute to the superposition of the corresponding structures used for the imaging mask master 12.

[0146] Again, as explained above in the context of Figures 7 and 8, lighting channel 27 i The distribution of incident position 33i can exist within the illumination electrodes I1 to I4.

[0147] Figure 11 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those explained above with reference to Figures 1 to 10, and particularly Figures 7 to 10, have the same reference numerals and will not be discussed in detail further.

[0148] A masking illumination pupil region 31 is generated according to the illumination setting 12a of Figure 11, the orientation and boundary of which are adapted to the associated masking exit pupil region 38. In terms of shape, the envelope 32 of the masking illumination pupil region 31 corresponds to the shape of the envelope of the masking exit pupil region 38. This shape of the envelope 32 is irregular and can be approximated by a horizontal ellipse (see Figure 10). The envelope 32 deviates from a circle.

[0149] The shading illumination pupil region 31 and the associated shading exit pupil region 38 have a non-central geometric centroid SP. This centroid SP is spaced (i.e., off-center) by a distance Δz from the center of the entrance pupil 12a or the exit pupil 36. Δz can range from 0.5% to 45% of the typical diameter of the entrance pupil 12a. Figure 11 illustrates this off-center Δz in an exaggerated manner.

[0150] According to Figure 11, the entrance pupil 12a is illuminated only by the illumination light 3 between the envelope 32 of the occluded illumination pupil region 31 and the edge 37 of the outer pupil. Illumination channel 27 i The incident position 33i can again be configured in a closely packed and uniformly distributed manner in this illumination region between the envelope 32 and the outer pupil edge 37.

[0151] In the illumination setting 12a according to Figure 11, the pupil is directly illuminated at the adjacent envelope 32. Alternatively, the envelope 32 and such incident point 33... i A distance Δ can exist between them again, as explained above in conjunction with Figure 8.

[0152] Figure 12 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 11, and particularly Figures 7 to 11, have the same reference numerals and will not be discussed in detail hereafter.

[0153] In the case of illumination pupil 12a according to FIG12, the envelope 32 of the shielding illumination pupil region 31, which is adapted to the shielding exit pupil region 38, is again completely omitted. Illumination is achieved only in the central illumination pole I outside this envelope 32, which has an approximately biconvex lens shape. Illumination pole I may have a boundary shape represented as a leaf. Illumination pole I of illumination pupil 12a according to FIG12 has a range such that along the cross diffraction pupil coordinate σ y Illumination is provided by illumination pupils 12a on both sides of envelope 32.

[0154] Besides the illumination pole I (whose orientation in the illumination pupil 12a corresponds to the zeroth-order diffraction orientation of the imaging beam 3 in the exit pupil 36), Figure 12 also shows the B+ and B- order diffraction within the exit pupil 36. The boundary of the illumination pole I ensures that the B+ and B- order diffractions remain entirely within the outer pupil edge 37. The “lens curvature” of the edge profile of the illumination pole I corresponds to the curvature of the outer pupil edge 37.

[0155] Figure 13 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 12, and particularly Figures 7 to 12, have the same reference numerals and will not be discussed in detail hereafter.

[0156] The entrance pupil 12a in Figure 13 is a variant of the dark-field illumination. The entrance pupil 12a in Figure 13 is illuminated only within the envelope 32, i.e., within the shielded illumination pupil region 31, which again corresponds to the shielded exit pupil region 38 of the projection optics unit 10. The envelope 32 is located at the normalized pupil coordinate σ. x , σ y An embodiment containing an ellipse, wherein the semi-major axis of this ellipse is along σ. x Coordinate extension. The incident pupil 12a will not be illuminated by the illumination light 3 between the envelope 32 and the outer pupil boundary 37.

[0157] Figure 14 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 13, and particularly Figures 7 to 13, have the same reference numerals and will not be discussed in detail hereafter.

[0158] The illumination pupil 12a in Figure 14 can be understood as a superposition of the illumination pupils 12a in Figures 10 and 13. Therefore, the area 31 of the blocking illumination pupil is illuminated first, and then the four illumination poles I1, I2, I3 and I4 are illuminated.

[0159] Figure 15 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 14, and particularly Figures 7 to 14, have the same reference numerals and will not be discussed in detail hereafter.

[0160] In principle, the illumination pupil 12a according to Figure 15 corresponds to the illumination pupil 12a according to Figure 8, wherein, within the outer envelope 34, the incident pupil 12a is uniformly illuminated by the illumination light 3. If through illumination channel 27 i Dispersion incident position 33 i The method of uniform illumination within the outer envelope 34 corresponds to the method explained above in the context of Figures 7 and 8, with the incident position 33. i It can also be located on the envelope 32 of the shading illumination pupil region 31 in an alternative variant of the incident pupil 12a.

[0161] Figure 16 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 15, and particularly Figures 7 to 15, have the same reference numerals and will not be discussed in detail hereafter.

[0162] The entrance pupil 12a according to Figure 16 is a variation of the entrance pupil 12a according to Figure 15. In the case of the entrance pupil 12a according to Figure 16, when the illumination light 3 illuminates the area of ​​the outer envelope 34, care must be taken to ensure that the entrance pupil 12a is not irradiated by the illumination light 3 around the envelope 32, especially at a distance Δ from the envelope 32. Therefore, in the entrance pupil 12a, there is at least a distance of 2Δ between the illumination light 3 inside the envelope 32 and the illumination light 3 outside the envelope 32. In this respect, the entrance pupil 12a according to Figure 16 corresponds to the entrance pupil 12a according to Figure 8.

[0163] Figure 17 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the corresponding exit pupil of the projection optics unit 10. Components and functions corresponding to those explained above with reference to Figures 1 to 16, and particularly Figures 7 to 16, have the same reference numerals and will not be discussed in detail further.

[0164] The illumination setting 12a in Figure 17 represents a variant of dark-field illumination. In this case, not the entire masking illumination pupil area 31 within the envelope 32 is illuminated, but only the area around the central incident position 33 is illuminated. z Part 39 is illuminated. Central incident position 33 zThe σ of the portion 39 surrounding (i.e., around the center of the occluded illumination pupil area 31) x σ is smaller than the entire occlusion illumination pupil area 31 x Therefore, the clear areas 40 and 41 that are not illuminated by the illumination light 3 are still located within the shaded illumination pupil area 31 of Figure 17, on the left and right sides of part 39.

[0165] Similar to the illustrations in Figures 9A and 12, Figure 17 also depicts B-order diffraction in the exit pupil 36, which occurs at the corresponding structure of the mask master 12. The center of this B-order diffraction is B... z Within the shading illumination pupil area 31 and the center 33 of the illumination portion 39 z Along the diffraction pupil coordinate σ x The distance is d from the diffraction path. Meanwhile, this illumination portion 39 represents the zeroth-order diffraction within the exit pupil 36.

[0166] The edge contour of portion 39 conforms to the diffraction path d, such that the diffracted portion 39 of the B-order diffraction is completely within the outer pupil edge 37 of the exit pupil 36. The projection 42 of the B-order diffraction outside the outer pupil edge 37 corresponds in shape and size to the sharp region 41 within the envelope 32 on the right side of FIG17.

[0167] Figure 18 illustrates a further embodiment of the illumination pupil 12a, which is adapted to the associated exit pupil 36 of the projection optics unit 10. Components and functions corresponding to those previously explained with reference to Figures 1 to 17, and particularly Figures 7 to 17, have the same reference numerals and will not be discussed in detail further.

[0168] Figure 18 also shows a variant of the illumination pupil 12a that can be used for dark field illumination.

[0169] Again, only a portion of the masking illumination pupil region 39 is illuminated, not the entire masking illumination pupil region 31. As a result, the sharp regions 40 and 41 of the left and right portions of 39 within the envelope 32 of the masking illumination pupil region 31 are not illuminated by the illumination light 3. In terms of shape and size, these sharp regions 40 and 41 correspond to the overlapping regions of the two B- and B+ diffraction orders of the masking illumination pupil region 31 and the exit pupil 36, which again diffract at the structure of the mask master 12, but this time with diffraction along the diffraction pupil coordinate σ. x The diffraction path or diffraction distance d, whose diameter with respect to the exit pupil 36 is smaller than the diffraction spacing d according to the embodiment of FIG17. Due to the relatively small diffraction distance d, the B- and B+ order diffractions overlap with the shielding illumination pupil region 31 in the clear regions 40, 41, which correspond in attitude and shape to the zeroth order diffractions within the exit pupil 36.

[0170] The following describes another embodiment of the illumination pupil 12a based on Figures 19 to 21, in which the illumination pupil 12a depends on its position in the object field 8 and is adapted to the exiting pupil 36 having the same object field dependence. Components and functions corresponding to those previously explained with reference to Figures 1 to 18, and especially Figures 7 to 18, have the same reference numerals and will not be discussed in detail again.

[0171] Figures 19 to 21 show the corresponding pupils 12a and 36 at three different x-positions (also represented as field heights) of the object field 8. Figure 19 shows the incident pupil 12a and its corresponding exit pupil 36, located at a field height of x = -13 mm, i.e., at the left x-field edge of the object field 8. Figure 20 shows the illumination pupil 12a and its corresponding exit pupil 36, located at the x-field center of the object field 8 (x = 0 mm). Figure 21 shows the incident pupil 12a and its corresponding exit pupil 36, located at the right x-field edge of the object field 8 (x = +13 mm). Therefore, based on the x-object field coordinates, with the illumination settings using the illumination pupil 12a according to Figures 19 to 21, the object field 8 is illuminated with different illumination angle distributions.

[0172] When the field height is x = 0 mm (Fig. 20), there is dark field illumination similar to that in Fig. 13, although it has an irregular envelope 32 of the masking illumination pupil region 31 as shown in Figs. 11 and 12. When the field height is x = 0, the masking illumination pupil region 31 of the illumination pupil 12a shown in Fig. 20 is centered within the outer pupil edge 37.

[0173] At the left edge of the object field (field height x = -13 mm, see Figure 19), the illumination pupil 12a (which corresponds to the exit pupil 36 at this field height of x = -13 mm) first appears at the negative cross-diffraction pupil coordinate σ. x The direction of displacement occurs, i.e. downwards in Figure 19, and it tilts slightly counterclockwise through σ. z coordinate.

[0174] At the right edge of the object field (field height x = +13 mm, see Figure 21), there exists a corresponding -σ value for the occluded illumination pupil region 31. y The displacement, which corresponds to the exit pupil 36 at the field height of x = 13 mm, although in this case it is about the pupil coordinate σ. z Inclined slightly in a clockwise direction in an equal but opposite manner.

[0175] Alternative field-dependent illumination pupils 12a (particularly those adapted to the corresponding field dependence of the exit pupil 36) may also exist in other illumination settings described herein, particularly in illumination settings with a deviated circular shading illumination pupil region 31, such as in illumination pupils 12a with an elliptical envelope 32, or in illumination pupils 12a with an irregular envelope 32 (e.g., refer to Figures 11 and 12).

[0176] Figures 22 to 24 are used to explain variations in the design of the illumination pupil 12a, which make it possible to adapt the field-dependent exit pupil 36. Components and functions corresponding to those previously explained with reference to Figures 1 to 21, particularly Figures 7 to 21, and especially Figures 19 to 21, have the same reference numerals and will not be discussed in detail again.

[0177] In the case of pupil adaptation according to Figures 22 to 24, the corresponding illumination pupil 12a is not field-dependent, that is, it has the same positioning, shape, and envelope 32 as the shielding illumination pupil region 31 within the outer pupil edge 37, independent of the field height (x = -13 mm, Figure 22; x = 0 mm, Figure 23; x = +13 mm, Figure 24). Conversely, in the embodiment according to Figures 22 to 24, the exit pupil 36 is field-dependent, which is the field-dependent form of Figures 19 to 21. Compared to the center position when the field height is x = 0 mm (Figure 23), the shielding exit pupil region 38 is at -σ y Displacement occurs in the direction, and it tilts slightly counterclockwise at the left edge of the field (x = -13 mm, see Figure 22) and then along the negative σ direction again. y Directional displacement, and pupil coordinate σ around the right field edge. z Slightly tilted clockwise (x = +13 mm, see Figure 24). In the case of field-independent illumination pupil 12a according to Figures 22 to 24, the degree to which the occlusion illumination pupil region 31 is smaller than the occlusion exit pupil region 38 is such that the occlusion illumination pupil region 31 is always completely located within the occlusion exit pupil region 38, regardless of the field dependence of the latter's attitude and orientation, as shown in Figures 22 to 24.

[0178] In a manner corresponding to the explanation given above regarding the x-dependency of the illumination pupil 12a and / or the exit pupil 36, particularly in conjunction with Figures 19 to 24, the illumination pupil 12 may also be adapted to the y-field dependency of the exit pupil 36 or to the combined x / y-field dependency of the exit pupil 36.

[0179] Figures 25 and 26 illustrate a further embodiment of the illumination pupil 12a, which is adapted to the associated exit pupil 36 of the projection optics unit 10. Components and functions corresponding to those explained above with reference to Figures 1 to 24, and particularly Figures 7 to 24, have the same reference numerals and will not be discussed in detail further.

[0180] The illumination pupil 12a according to Figures 25 and 26 is generated by means of the illumination optical unit 11 of the projection exposure apparatus 1. In this case, the first faceted mirror 6 is disposed in the field plane of the illumination optical unit 11 and the second faceted mirror 7 is disposed on the pupil plane of the illumination optical unit 11. For example, the illumination optical unit 11 may be equipped with a field faceted mirror according to Figure 3 and a pupil faceted mirror according to Figure 5, wherein these faceted mirrors may comprise a monolithic transmission facet 21 and an illumination specification facet 25 or facets 21, 25 subdivided into individual mirrors ES, as explained above.

[0181] The illumination pupil 12a in Figures 25 and 26 is drawn at this location using a pupil coordinate system at different scales.

[0182] Figure 25 shows the normalized pupil coordinates σ. x σ y A diagram of the selected illumination pupil 12a, in which the outer pupil edge 37 has the same σ at the position of the maximum possible object field illumination angle in all cases. x / σ y Value. Therefore, in Figure 25, the pupil coordinate σ x σ y This is normalized to ensure that the outer pupil edge 37 is circular, regardless of its actual shape in absolute pupil coordinates. The pupil representations in Figures 9 to 24 also use this normalized pupil coordinate σ. x σ y .

[0183] Figure 26 shows the illumination pupil 12a in Figure 25, whose absolute pupil coordinates are ρ. x ρ y This refers to the coordinates representing the measured actual illumination angle on the object field. For example, this absolute pupil coordinate ρ... x ρ y The coordinates represent the measured sine of the incident angle of the illuminating light 3 on the object field 8. These are the actual absolute pupil coordinates ρ. x ρ y In the illumination pupil 12a, the overall shape is elliptical, and its semi-major axis is along the pupil coordinate ρ. xFurthermore, in absolute pupil coordinates, the illumination pupil 12a has an elliptical occlusion region 31, which also has an elliptical envelope 32, whose semi-major axis is along the pupil coordinate ρ. x Figures 25 and 26 indicate the corresponding illumination channels 27 transmitted through the field plane 21 and the pupil plane 25, respectively. i Incident position 33 i The incident positions are distributed in a dispersed manner within the occluded illumination pupil area 31.

[0184] The semi-axis ratio of the envelope 32 may be different from the semi-axis ratio of the outer pupil edge 37. Therefore, according to the diagram in the normalized pupil coordinates of FIG25, a circular outer pupil edge 37 is generated, but the circular envelope 32 of the illumination pupil region 31 is not obscured.

[0185] In the following explanation of the illumination pupil 12a according to Figures 27 to 42, and in each case adapted to the corresponding exit pupil 36, the pupil in each case is in the normalized pupil coordinate σ according to Figure 25. x σ y The diagram is shown in the first figure, and the absolute pupil coordinates ρ correspond to those in Figure 26. x ρ y As illustrated in the following diagram.

[0186] The illumination pupils shown in Figures 27 to 42 are also generated by means of an illumination optical unit 11 in the form of a so-called fly-eye integrator. In this case, the first faceted mirror 6 is disposed in the pupil plane of the illumination optical unit 11, and the second faceted mirror 7 is disposed in the pupil plane of the illumination optical unit 11.

[0187] Another pupil embodiment will be described below based on Figures 27 and 28, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 26, especially Figures 7 to 26, and especially Figures 25 and 26 have the same reference numerals and will not be discussed in detail hereafter.

[0188] In the case of the illumination optical unit 12a according to Figures 27 and 28, the shielding illumination pupil region 31 within the envelope 32 is not illuminated by the illumination light 3. The illumination channel 27 is set by the tilt angles of the facets 21 and 25 of the illumination optical unit 11. i Incident position 33 iThe illumination pupils exist in a distributed configuration between the envelope 32 and the outer pupil edge 37, thus providing a uniform illumination intensity per unit area of ​​the illumination pupil 12a between the envelope 32 and the outer pupil edge 37, within a specified tolerance. In this respect, the illumination setting 12a according to Figures 27 and 28 is equivalent to the illumination setting according to Figure 11. Conversely, the occlusion illumination pupil region 31 in the illumination pupil 12a according to Figures 27 and 28 is located at the center, and the envelope 32 is at the absolute pupil coordinate ρ. x ρ y It has an approximately elliptical shape (see Figure 28) and in the normalized pupil coordinates σ x , σ y It presents a shape similar to a stadium (see Figure 27).

[0189] Another pupil embodiment will be described below based on Figures 29 and 30, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 28, especially Figures 7 to 28, and especially Figures 25 to 28 have the same reference numerals and will not be discussed in detail hereafter.

[0190] According to Figures 29 and 30, the illumination pupil 12a is illuminated by the illumination light 3 between the envelope 32 of the shielding illumination pupil region 31 and the outer envelope 34 of the outer illumination pupil region 35. Except that the pupil is not illuminated within the shielding illumination pupil region 31 in the case of illumination pupil 12a, the illumination pupil 12a according to Figures 29 and 30 is in this respect equivalent to the illumination pupil 12a according to Figure 8.

[0191] In the case of illumination pupil 12a according to Figures 29 and 30, the illumination pupil is not illuminated within the envelope 32 or between the outer envelope 34 and the outer pupil edge 37.

[0192] In terms of the boundary shape of the envelope 32, the illumination pupil 12a according to Figures 29 and 30 is equivalent to the illumination pupil 12a according to Figures 27 and 28.

[0193] The outer envelope 34, as shown in Figure 29, has a circular shape in normalized pupil coordinates and is again elliptical in absolute pupil coordinates, with its semi-major axis along the pupil coordinate ρ. x (See Figure 30).

[0194] Another pupil embodiment will be described below based on Figures 31 and 32, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 30, especially Figures 7 to 30, and especially Figures 25 and 30, have the same reference numerals and will not be discussed in detail hereafter.

[0195] In the case of illumination pupil 12a according to Figures 31 and 32, both the blocking illumination pupil region 31 and the outer illumination pupil region 35 located between the envelope 32 and the outer envelope 34 are illuminated by appropriate incident positions 33. i Illuminated by illumination light 3. Illumination pupil 12a is not illuminated by illumination light 3 in the area surrounding the illumination pupil 32, which again corresponds to the area of ​​the exit pupil 36 adjacent to the edge of the associated shielding exit pupil area 38. In this respect, illumination pupil 12a according to FIG. 31 and FIG. 32 corresponds to illumination pupil 12a according to FIG. 16.

[0196] Figure 32 also illustrates the incident position 33 of the illumination light 3, which is first within the envelope 32 and then outside the envelope 32. i The minimum distance between them is 2Δ.

[0197] Another pupil embodiment will be described below based on Figures 33 and 34, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 32, especially Figures 7 to 32, and especially Figures 25 and 32 have the same reference numerals and will not be discussed in detail.

[0198] According to Figures 33 and 34, the illumination pupil 12a is first a dark-field illumination pupil of the pattern shown in Figure 25, and then a superposition of an x-dipole illumination pupil with poles I1 and I2, where poles I1 and I2 are represented as along the pupil coordinate σ. y / ρ y The two σ bands of the extended pupil band x / ρ x Illumination in the pupil coordinate region. Compared to the illumination pupil 12a in Figure 14, the illumination poles I1 and I2 have a continuous embodiment, that is, they are in the σ region of the occluded illumination pupil region 31. y / ρ y There is no interruption at the location of the pupil coordinates.

[0199] Another pupil embodiment will be described below based on Figures 35 and 36, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 34, especially Figures 7 to 34, and especially Figures 25 and 34, have the same reference numerals and will not be discussed in detail hereafter.

[0200] The illumination pupil 12a according to Figures 35 and 36 corresponds to the illumination pupil according to Figure 14, except that the boundary shapes of the envelope 32 and the outer pupil edge 37 are both elliptical in absolute pupil coordinates (see Figure 36) and except that the illumination pupil 12a according to Figures 35 and 36 is generated using the second faceted mirror 7 arranged in the pupil plane of the illumination optical unit 11.

[0201] According to Figures 35 and 36, the four illumination poles I1 to I4 of the illumination pupil 12a can be understood as bipolar illumination settings according to Figures 33 and 34, having pupil coordinates σ along the occluded illumination pupil region 31. y / ρ y σ y / ρ y Δσ of the lighting strip y / Δρ y Interrupted.

[0202] Another pupil embodiment will be described below based on Figures 37 and 38, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 36, especially Figures 7 to 36, and especially Figures 25 and 36 have the same reference numerals and will not be discussed in detail hereafter.

[0203] Similar to the illumination optical unit 12a according to Figures 35 and 36, the illumination pupil 12a according to Figures 37 and 38 is a superposition of the dark field illumination pupil according to Figures 25 and 26 and the quadruple illumination setting having four illumination poles I1 to I4.

[0204] Unlike the illumination pupil 12a according to Figures 35 and 36, the four poles I1 to I4 of the four-pole illumination setting component of the illumination pupil 12a according to Figures 37 and 38 are formed at a specific σ. y / ρ x Within the range of two pupil stripes, each of them is along σ x / ρ x - The pupil coordinates extend and each of them terminates at σ relative to the occluded illumination pupil region 31. x / ρ x -Δσ corresponding to the pupil coordinates x / Δρ x - Within the pupil coordinate range.

[0205] Unlike the illumination pupil 12a described above (e.g., illumination pupils 12a according to Figures 9A / 9B, 10, 12, 17 and 18), the illumination pupil 12a according to Figures 37 and 38 takes into account the illumination light 3 along the pupil coordinate σ. y / ρ y Diffraction at the structure of mask master 12, σ y / ρy This represents the diffraction pupil coordinates. The illumination beam cut between poles I1 and I2 on one side and poles I3 and I4 on the other side ensures that the light along the pupil coordinates σ... y / ρ y The imaging light 3 diffracted into the exit pupil 36 will not undesirably diffract into the occluded illumination pupil region 31.

[0206] Another pupil embodiment will be described below based on Figures 39 and 40, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 38, especially Figures 7 to 38, and especially Figures 25 and 38, have the same reference numerals and will not be discussed in detail hereafter.

[0207] In the illumination pupil 12a according to Figures 39 and 40, a central dark field illumination re-exists within the occlusion illumination pupil region 31, corresponding to the illumination pupil 12a according to Figures 25 and 26. This dark field illumination is combined with a quadrupole illumination setting having illumination poles I1 to I4, wherein illumination poles I1 to I4 are located at positive σ. x / ρ x Direction (I1), positive σ y / ρ y Direction (I2), negative σ x / ρ x Direction (I3), and negative σ y / ρ y Direction (I4). Unlike the case of the illumination pupil 12a with four illumination poles I1 to I4 described above, the four illumination poles I1 to I4 therefore do not exist within the four quadrants Q1 to Q4 in the illumination settings according to Figures 39 and 40, but are instead along the pupil coordinates + / -σ. x and + / -σ y The direction of illumination. Illumination electrodes I1 to I4 are each positioned near the edge 37 of the outer pupil, resulting in illumination of the object field 8 at a large illumination angle. Therefore, within the normalized pupil coordinate range, illumination electrodes I1 to I4 are positioned at σ coordinate radii between 0.8 and 1.

[0208] Another pupil embodiment will be described below based on Figures 41 and 42, which can be used to replace the illumination pupils adapted to the exit pupils as described above. Components and functions corresponding to those explained above with reference to Figures 1 to 40, especially Figures 7 to 40, and especially Figures 25 and 40, have the same reference numerals and will not be discussed in detail hereafter.

[0209] The illumination pupil 12a according to Figures 41 and 42 again includes the illumination of the occluded illumination pupil region 31, similar to the illumination pupil 12a according to Figures 25 and 26, i.e., the dark field illumination component. Furthermore, according to Figures 41 and 42, there are eight additional illumination poles I1 to I8 in the illumination pupil 12a.

[0210] The illumination electrodes I1 to I4 are configured according to the pattern of illumination electrodes I1 to I4 of illumination pupil 12a in Figures 39 and 40.

[0211] Additional illumination poles I5 to I8 are positioned in the middle illumination angle region of the four quadrants of the illumination pupil 12a according to Figures 41 and 42, i.e., in the normalized pupil coordinate σ with a radius of approximately 0.5. x σ y Within the range.

[0212] Figures 43 and 44 are used to describe another illumination pupil 12a, which is adapted to the corresponding exit pupil 36, in the following description. Components and functions corresponding to those explained above with reference to Figures 1 to 42, and especially Figures 7 to 42, have the same reference numerals and will not be discussed in detail again.

[0213] Figure 43 shows the target illumination pupil 45, which can be the result of simulation calculations performed to optimize the illumination of the mask master 12, which is structured in a specific manner. The target illumination pupil has an intensity distribution of illumination light 3, which in principle corresponds to the intensity distribution of illumination pupil 12a in Figure 29. Illumination light 3 is used to illuminate the target illumination pupil 45 located in the region between the envelope 32 of the shielding illumination pupil region 31 (which in turn adapts to the shielding exit pupil region of the exit pupil 36) and the outer envelope 34 of the outer illumination pupil region 35.

[0214] In the target illumination pupil 45, the envelope 32 of the occlusion illumination pupil region 31 has a boundary shape that approximates the shape of a stadium, and it has a boundary shape along σ. x The pupil line extends from two straight lines and connects these two lines with two curves. The outer envelope 34 is circular in the pupil coordinate system. In the case of the target illumination pupil 45, there is a uniform and constant intensity distribution of the illumination light 3 between the inner envelope 32 and the outer envelope 34.

[0215] The illumination pupil 12a in Figure 44 is plotted as the so-called x-field average. Therefore, the illumination pupil 12a is shown as the x-average of all field heights of the object field 8.

[0216] The target illumination pupil 45 according to Figure 43 can be specified in a plotted form in normalized pupil coordinates (e.g., according to Figure 25) or in absolute pupil coordinates (e.g., as shown in Figure 26). For example, the outer pupil edge 37 can be circular in the normalized pupil coordinates shown in Figure 43, but can also be circular in the absolute pupil coordinates.

[0217] Figure 44 shows illumination pupil 12a, which represents the actual illumination pupil approximating the target illumination pupil 45 shown in Figure 43, and is generated by illumination optics unit 11 using a second faceted mirror 7 at a distance from the pupil plane of illumination optics unit 11 (see exemplary illumination optics unit 11 according to Figure 6). Due to the flexibility of the allocation and setting options of individual mirrors ES (in particular, the grouping options of these individual mirrors ES of the two faceted mirrors 6, 7) to form transmission facet group 21 and illumination specification facet group 25, the target illumination pupil 45 according to Figure 43 can be almost perfectly reproduced in the x-field average using the actual illumination pupil 12a according to Figure 44. In particular, uniform and constant illumination within envelopes 32 and 34 can be achieved in the x-field average (i.e., except for the y-field coordinates) integrated over the x-field coordinates, or an approximation of the target intensity distribution can be selectively achieved.

[0218] Figures 45 and 46 are used to explain the sequential and / or parallel, field-dependent use of the various illumination pupils 12a described above when imaging different regions of the exemplary mask master 12. Components and functions corresponding to those previously explained with reference to Figures 1 through 44 have the same reference numerals and will not be discussed in detail again.

[0219] The mask master 12 according to Figure 45 has a fine-structured region 46, which requires a particularly high projection exposure resolution through the projection exposure device 1. For example, the fine structure 46 can be lines that are very closely spaced in the y-direction, i.e., vertical lines in Figure 45.

[0220] Furthermore, in the x-field height region, the mask master 12 has a coarse structure 47, whose typical structural range is larger than that of the fine structure 46. In the examples discussed below, the coarse structure 47 is again a vertical line, which has a larger x-range and periodicity compared to the fine structure 46.

[0221] The mask master 12 further includes a transition region 48 between a field height region having a fine structure 46 and a field height region having a coarse structure 47. The fine structure 46 may also exist on the mask master 12 within the transition region 48. The transition region 48 is spatially adjacent to the region of the coarse structure 47.

[0222] Figure 46 shows an example of an illumination pupil 12a adapted for the fine structure 46. This illumination pupil 12a corresponds to the illumination pupil explained in Figure 10 above.

[0223] According to Figure 46, the illumination pupil 12a is used for the x-field height of the mask master in which the fine structure 46 exists. Since the illumination light 3 is along the pupil coordinate σ at the fine structure 46... x The diffraction, on one hand, includes the diffraction shift or diffraction distance d between the illumination electrodes I1 and I2 on the other hand and the illumination electrodes I3 and I4 on the other hand, which corresponds to the σ between the two electrodes I1 and I2 on one hand and I3 and I4 on the other hand. y distance.

[0224] Furthermore, the illumination optics unit 11 is configured such that illumination setting 12a is set at the x-field height of the coarse structure 47 and the transition region 48, which differs from illumination setting 12a according to FIG. 46 and corresponds to illumination setting 12a according to FIG. 14. Therefore, the structure of the mask master in the coarse structure 47 and the transition region 48 is illuminated using illumination setting 12a according to FIG. 47 (including dark field illumination within the masking illumination pupil region 31). Since the transition region 48 also contains only the fine structure of the mask master 46, the illumination light illuminating the masking illumination pupil region 31 is diffracted at that structure to the pupil regions B+ and B- outside the outer pupil edge 37 according to the diffraction shift d; these regions are blocked by the aperture stop of the projection optics unit 10, and therefore do not undesirably reach the wafer 19.

[0225] The various edge profiles of the shielding exit pupil region 38 will be explained below based on Figures 48 and 49; the corresponding illumination pupil 12a (especially the shielding illumination pupil region) can be adapted to this edge profile using the above-described techniques. Components and functions corresponding to those previously explained with reference to Figures 1 to 47 have the same reference numerals and will not be discussed in detail hereafter.

[0226] Figure 48 shows the edge contour of the region 38 that blocks the exit pupil. i Variations. Within the scope of methods for calculating appropriate control of the individual reflectors ES or facets 21, 25 for the illumination optics unit 11, these edge profiles 49 are parameterized in terms of shape. i An appropriate envelope 32 can be used to specify the occlusion region 31 of each illumination pupil 12a.

[0227] Figure 48 shows the edge contour of the region 38 that blocks the exit pupil. i The first design of which is assigned to the projection optical unit 10 of the projection exposure device 1.

[0228] The edge contour 491 of the shielding exit pupil region 38 has a vertical elliptical shape, with its semi-major axis along the pupil coordinate σ. y extend.

[0229] The edge profile 492 is roughly teardrop-shaped, with its straight profile segment located at the bottom of Figure 48. This edge profile 492 represents a parameterized variant of the actual edge profile of the shielding exit pupil region 38 of the first design of the projection optical unit 10, which is neither rotationally symmetric nor has multiple rotational symmetries.

[0230] Edge profile 493 represents the circle inscribed within edge profile 491, that is, it represents the smallest circle diameter that completely accommodates edge profile 491.

[0231] Edge profile 494 represents the smallest rectangle that accommodates edge profile 491, i.e., it has a dimension along σ corresponding to the corresponding dimension of edge profile 491. x Coordinates and σ y The edge length of the coordinate.

[0232] Edge contour 495 is circular, and its area is exactly the same as that of edge contour 491.

[0233] Using edge contours 491 to 495, the actual edge contours of the shielding exit pupil region 38 of the projection optical unit 10 can be approximated in a parameterized manner, such that these edge contours 491 to 495 can be used to specify the envelope 32 of the shielding illumination pupil region of the illumination pupil 12a adapted to this exit pupil 36.

[0234] Figure 49 shows a corresponding approximation of the actual edge contours 501 to 505 to the shielded exit pupil region 38 of another design embodiment of the projection optical unit 10 of the projection exposure device 1.

[0235] Approximately, the edge profile 501 has the shape of a horizontal ellipse, which extends along the pupil coordinate σ. x It has a relatively large range.

[0236] Edge profile 502 again represents the asymmetric edge profile parameterization, which approximates the shape of a spherical triangle.

[0237] Edge contour 503 again presents the circle inscribed within edge contour 501.

[0238] Edge contour 504 presents a rectangle inscribed within edge contour 501.

[0239] The edge contour 505 is circular, and its area is equal to the area of ​​the edge contour 501.

[0240] In terms of parameterized boundary conditions, edge profiles 501 to 505 therefore correspond to edge profiles 491 to 495, which are now applicable to further design of the projection optical unit 10, i.e., to alternative edge profile designs that actually block the exit pupil region 38.

[0241] Regarding the possible edge contour shape of the envelope 32 of the shading illumination pupil region 31, which can be used to adapt to the configuration, orientation, and shape of the edge contour of the shading exit pupil region 38, the following boundary conditions may be applied:

[0242] With standardized pupil coordinates σ x σ y The average radius of the envelope 32 can be in the range of 0.1 to 0.3, especially between 0.2 and 0.22.

[0243] The average radius of envelope 32 can vary along the x-field height within tolerances of no more than 10%, no more than 5%, no more than 2%, or no more than 1%. This variation in the average radius represents the field dependence of the shading illumination pupil region 31.

[0244] In the normalized pupil coordinates, σ x Eccentricity and / or σ y The eccentricity can be in the range of -0.2 to +0.2, particularly in the range of -0.1 to +0.1, for example, in the range of -0.05 to +0.05 or in the range of -0.005 to +0.005. This eccentricity of envelope 32 can be related to the field height, as explained above in the context of Figures 19 to 21.

[0245] The deviation of the envelope 32 from the ideal circle (described, for example, by the ratio of the semi-axis lengths of the ellipse) can be in the range of 0.5 (semi-axis length ratio of 1:2) and 2 (semi-axis length ratio of 2:1).

[0246] Generally, the edge contour of the exit pupil region 38 and / or the edge contour of the envelope 32 of the illumination pupil region 31 can be, for example, in the normalized pupil coordinates σ. x σ y The parameterization is as follows, as explained in the example using envelope 32:

[0247]

[0248] Here, The radius of the envelope 32 is measured from the center of the incident pupil 12a, for example, from the corresponding azimuth angle. The centroid of the area of ​​the outer pupil edge 37 in the direction is measured;

[0249] r0 is the average radius of the envelope 32;

[0250] s n and c n These are the coefficients of the nth-order Fourier contribution.

[0251] For example, s1 provides an eccentricity of envelope 32.

[0252] For example, for smaller values, c2 describes the deviation of the envelope shape from an ideal circle to an approximate ellipse.

[0253] In preparation for the production of the microstructured component, the structural distribution present on the mask master 12 is first examined, particularly the structural size distribution and structural orientation distribution. Furthermore, as described above, the shape of the exit pupil 36, and especially the envelope of the region 38 that shields the exit pupil, is parameterized. Subsequently, the target illumination pupil, such as one of the variations described above, is specified using the mask master verification results and the parameterization of the exit pupil 36, and is set as the illumination pupil 12a by means of the illumination optics unit 11 of the projection exposure apparatus 1.

[0254] To produce microstructured components, particularly highly integrated semiconductor components (e.g., memory chips), using projection exposure equipment 1, a mask 12 and a wafer 19 are subsequently provided. The structure on the mask 12 is then illuminated with illumination light 3 using a suitably configured illumination optics unit 11, and projected onto a photosensitive layer on the wafer 19 using the projection optics unit of the projection exposure equipment 1. By developing the photosensitive layer, a microstructure is then formed on the wafer 19, thereby producing a microstructured or nanostructured component.

[0255] The components produced can be microchips, especially memory chips.

Claims

1. An optical system for a projection exposure apparatus (1), - having an illumination optics unit (11) for guiding illumination and imaging light (3) from a light source (2) to a subject field (8), wherein an object (12) to be imaged can be disposed in the subject field; - having an imaging optics unit (10) for imaging the subject field (8) into an image field (17), wherein a substrate (19) to be exposed can be disposed in the image field, the imaging optics unit (10) including an exit pupil (36) having at least one shielding exit pupil region (38) located within an outer pupil edge (37); - the illumination optics unit (11) is configured such that when the subject field (8) is illuminated by the illumination and imaging light (3), an illumination angle distribution is generated, and the illumination angle distribution can be described by an illumination pupil (12a), wherein the illumination pupil region (31; I) of the illumination pupil illuminated by the illumination light is a shielding exit pupil region (38). i ; 35) The shielding exit pupil region (38) adapted to the imaging optical unit (10) - the shielding exit pupil region (38) of the imaging optical unit (10) has a non-central geometric centroid (SP).

2. An optical system for a projection exposure apparatus (1), comprising: - an illumination optics unit (11) for guiding illumination and imaging light (3) from a light source (2) to a subject field (8), wherein an object (12) to be imaged can be disposed in the subject field; - an imaging optics unit (10) for imaging the subject field (8) into an image field (17), wherein a substrate (19) to be exposed can be disposed in the image field; the imaging optics unit (10) includes an exit pupil (36) having at least one shielding exit pupil region (38) located within an outer pupil edge (37); - the illumination optics unit (11) is configured such that when the subject field (8) is illuminated by the illumination and imaging light (3), an illumination angle distribution is generated, and the illumination angle distribution can be described by an illumination pupil (12a), wherein the illumination pupil region (31; I) of the illumination pupil illuminated by the illumination light is... i ; 35) The shielding exit pupil region (38) adapted to the imaging optical unit (10), - the illumination optical unit (11) is implemented such that an illumination angle distribution appears in the object field (8) and the illumination angle distribution can be described by an illumination pupil (12a) having a shielding illumination pupil region (31), the envelope of which deviates from a circle in the following: -- the pupil coordinates (σ) normalized with respect to the edge (37) of the outer pupil x , σ y ), and / or -- in absolute pupil coordinates (ρ x , ρ y )middle.

3. The optical system as described in claim 1 or 2, characterized in that... In one embodiment, the illumination pupil (12a) is not illuminated by the illumination light (3) in at least one illumination pupil region (31) corresponding to the shielding emission pupil region (38).

4. The optical system as described in any one of claims 1 to 3, wherein an object structure is implemented for illuminating the object (12), which causes the imaging light (3) to travel along the diffraction pupil coordinates (σ) of the exit pupil (36). x , σ y Diffraction occurs downstream of the object (12), at coordinates (σ) of the diffraction pupil. x Vertical cross diffraction pupil coordinates (σ) y The range of illumination pupil coordinates (Δσ) y Within the area, the illumination light (3) does not illuminate the illumination pupil (12a), and the coordinate range of the illumination pupil corresponds to the area of ​​the shielded exit pupil (38) along the coordinates (σ) of the cross diffraction pupil. y ) range.

5. The optical system as described in any one of claims 1 to 4, characterized in that, The illumination pupil (12a) includes a shielding illumination pupil region (31) in which the illumination pupil (12a) is not illuminated by the illumination light (3), wherein the illumination angles assigned to the shielding illumination pupil region (31) correspond at least partially to the imaging beam angle of the zeroth order diffraction of the shielding exit pupil region (38), and the illumination pupil (12a) is illuminated by the illumination light (35) in the illumination pupil region (35) of the illumination pupil (12a). i I) is configured to be directly adjacent to the shading illumination pupil area (31).

6. The optical system as described in any one of claims 1, 2, 4, or 5, characterized in that... In the following embodiment, the illumination pupil (12a) having an illumination pupil region (31) corresponding to the illumination pupil region (38) is illuminated by the illumination light (3).

7. The optical system as claimed in claim 6, characterized in that... In the following embodiment, the illumination pupil (12a) is illuminated by the illumination light (3) in the illumination pupil region (35) that includes the shielding illumination pupil region (31).

8. The optical system as claimed in claim 7, characterized in that, The illumination pupil region (31, 35) is not illuminated by the illumination light (3) in the area surrounding the illumination pupil (Δ), which corresponds to the area adjacent to the edge of the exit pupil and the area of ​​the shielded exit pupil region (38).

9. The optical system as claimed in claim 6, characterized in that... In the following embodiment, the illumination pupil (12a) is illuminated only in the shielded illumination pupil area (31) corresponding to the shielded emission pupil area (38).

10. The optical system as claimed in claim 9, characterized in that, The shielding exit pupil region (38) includes at least one segment (40, 41) in which the shielding illumination pupil region (31) is not illuminated by the illumination light (3).

11. The optical system as claimed in any one of claims 1 to 10, characterized in that... The object field (8) serves as the field-dependent illumination pupil (12a).

12. The optical system as claimed in any one of claims 1 to 10, characterized in that, The imaging optical unit (10) is configured such that the exit pupil (36) of the imaging optical unit (10) is field-correlated with the object field (8), wherein the illumination optical unit (11) is configured such that the illumination pupil (12a) has a field correlation corresponding to the exit pupil (36).

13. The optical system of any one of claims 1 to 12, wherein the outer edge contour (49) of the shielding exit pupil region (38) i 50 i It has a shape that can be described by at least one of the following parameters: - the edge profile (49 i 50 i The average radius of the edge profile ranges from 0.1 to 0.3 of the normalized pupil coordinate radius. i 50 i The eccentricity ranges from 0.0025 to 0.05 of the normalized pupil coordinate radius, - the edge profile (49 i 50 i The average deviation from the circle ranges between 0.01 and 0.2 of the normalized pupil coordinate radius.

14. The optical system as claimed in any one of claims 1 to 13, characterized in that, The illumination optical unit (11) includes: - a field plane mirror (6) disposed in the field plane of the illumination optical unit (11); and - a pupil plane mirror (7) disposed in the pupil plane of the illumination optical unit (11).

15. The optical system as claimed in any one of claims 1 to 14, characterized in that, The transmission facet of the transmission facet of the illumination optical unit and / or the illumination specification facet of the illumination specification facet of the illumination optical unit are subdivided into a plurality of individual mirrors (ES), which are independently tiltable to designate the illumination pupil (12a).

16. The optical system as claimed in any one of claims 1 to 15, characterized in that... The light source (2) used for the illumination and imaging light (3).

17. A projection exposure apparatus having an optical system as claimed in any one of claims 1 to 16.

18. A method for specifying an illumination pupil (12a) of an illumination optical unit (11) for illuminating an object field (8) with illumination light (3), wherein an object (12) to be imaged can be configured in the object field, the method comprising the steps of: - analyzing the diffraction behavior of at least one object structure (46, 47) of the object (12), - detecting the position of a shielded exit pupil region (38) in an exit pupil (36) of an imaging optical unit (10) for imaging the object (12), and - adjusting the illumination pupil (12a) such that this produces an optical system according to any one of claims 1 to 15.

19. The method as described in claim 18, characterized in that, This results in a field-dependent illumination pupil (12a) that is adapted to the exit pupil (36) and / or the object structure (46, 47).

20. A method for producing microstructured components, comprising the following steps: - performing the method according to claim 18 or 19, - providing an object (12) having the analyzed diffraction behavior in the form of a mask master (12), - providing a wafer (19) having a coating sensitive to the illumination light (3), - projecting at least one segment of the mask master (12) onto the wafer (19) by means of a projection exposure apparatus (1) according to claim 17, using an optical system having a suitably adapted illumination pupil (12a), - developing the photosensitive layer exposed by the illumination light (3) on the wafer (19).

21. A component manufactured according to the method of claim 20.

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