Facet mirror of the illumination optical unit of a projection exposure apparatus

Abstract

The facet mirror of the illumination optical unit of the projection exposure apparatus has a facet body (35) and a plurality of displaceable individual facets (8) each having a reflecting surface (36) provided thereon. i ) with individual facets (8 i At least some of the ribs 34 have a range of displacement such that they contact the abutment surface 38 at one or more displacement positions.

Description

[Technical Field]

[0001] This application claims priority from German Patent Application No. 10 2019 214 269.9, the content of which is incorporated herein by reference.

[0002] The invention relates to a facet mirror of an illumination optical unit of a projection exposure apparatus. The invention further relates to individual facets of a facet mirror of an illumination optical unit of a projection exposure apparatus. The invention also relates to an illumination optical unit, an illumination system, an optical system, and a projection exposure apparatus comprising such a facet mirror. Finally, the invention also relates to a method for producing microstructured or nanostructured components and components produced by said method. [Background technology]

[0003] Facet mirrors of illumination optical units of projection exposure apparatuses having a large number of displaceable individual facets are known from the prior art, where the individual facets are designed so that they do not interfere with one another when the displacement is controlled, in particular so that the facets do not come into contact with one another during the displacement.

[0004] Mechanisms are known from the prior art that protect the facets of a facet mirror from unwanted movement, especially during transport, but these mechanisms do not protect the facets during normal operation of the facet mirror. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved facet mirror for an illumination optical unit of a projection exposure apparatus. [Means for solving the problem]

[0006] This object is achieved by the features of claim 1.

[0007] The essence of the invention is to form the individual facets of the facet mirror so as to come into contact with the abutment surface in one or more displacement positions. The individual facets of the facet mirror may in particular be formed so as to come into contact with the abutment surface in reversibly adjustable displacement positions. Such reversibly adjustable displacement positions are also referred to as active or actuatable displacement positions. In particular, the individual facets may have one or more discrete displacement positions. The individual facets may also be formed so as to come into contact with the abutment surface only in the event of undesired deflections, in particular in the case of parasitic movements, in particular in the case of transportation and / or earthquakes. Such deflections are also referred to as passive displacement positions. In case of uncertainty, the displacement positions include both actively and passively possible displacement positions.

[0008] In this case, the facets are in contact with respective abutment surfaces or abutment elements arranged on the body, preferably with the reflective surfaces of the individual facets being non-contact.

[0009] The abutment surface is in particular a defined, in particular predetermined abutment surface. The abutment surface is in particular an abutment surface where two adjacent facets abut against each other. The abutment surface is in particular spaced apart from the reflective surface of each individual facet. In particular, the abutment surface and the reflective surface of the individual facet form a discontinuous area.

[0010] The abutment surfaces are in particular formed on the facet body, respectively, and may be formed or arranged on the facet body in such a way that, in projection in the direction of a surface normal of the reflective surface of the individual facet, in particular in projection in the direction of a surface normal passing through the centroid of the reflective surface of the individual facet, they form an outer boundary of the projection of the facet body or protrude beyond said boundary in at least one direction perpendicular to the surface normal.

[0011] The projection is in particular a parallel projection, in particular an orthogonal projection.

[0012] The projection is in particular a projection onto a projection plane that is in particular perpendicular to the surface normal.

[0013] The present invention has recognized that this makes it possible to prevent facets from colliding with one another in an uncontrolled manner. Uncontrolled colliding is understood here to mean that facets collide with one another in uncontrolled, particularly unwanted, areas. In particular, it is possible to prevent the reflective surfaces of individual facets from colliding with one another. This makes it possible to prevent damage to the reflective surfaces.

[0014] The individual facets can be specially formed to come into contact with the abutment surface only in actuated and settable displacement positions, in particular, no undesired or unpredictable external effects on the individual facets are a prerequisite for contact with the abutment surface.

[0015] The individual facets can also be formed in such a way that they come into contact with the abutment surface in the event of unwanted or unpredictable external influences, in particular only in the event of unwanted or unpredictable external influences.

[0016] According to one aspect of the invention, at least some of the individual facets, in particular all of the individual facets, have a displacement range such that adjacent individual facets touch in one or more displacement positions. The individual facets may touch each other in particular in passive displacement positions.

[0017] The individual facets are preferably arranged in a non-contact manner in a base or neutral position, in particular spaced apart from one another, and in particular may be arranged spaced apart from all abutment surfaces in at least one active displacement position, in particular in all active displacement positions.

[0018] Generally, the present concept relates to an optical module having a plurality of displaceable optical elements.

[0019] According to one aspect of the invention, adjacent individual facets are each spaced apart from one another by a gap in the base or neutral position. Corresponding gaps may also be present in predetermined switching positions, in particular in any desired switching position. In particular, it is preferred that the reflective surfaces of the individual facets are each spaced apart from one another in the base or neutral position.

[0020] In the base or neutral position, the individual facets are also spaced apart from all abutment surfaces, in particular by gaps.

[0021] The gap is large enough to displace the individual facets within the displacement range. On the other hand, the gap is as narrow as possible to allow for close packing of the individual facets. The width of the gap between adjacent individual facets may be particularly less than 1 mm, particularly less than 0.5 mm. The width of the gap is particularly 50% or less, particularly 30% or less, particularly 20% or less, particularly 15% or less, particularly 10% or less, particularly 5% or less, particularly 3% or less, particularly 2% or less, particularly 1% or less of the size of the individual facet, particularly in the corresponding direction of its body or its surface.

[0022] In particular, the range in which the facets can be operatively displaced is referred to as the displacement of the individual facets. This range is also referred to as the active displacement range. Furthermore, in particular during transport of the facet mirror, it may be possible for the individual facets to be displaced as a result of external effects, for example vibrations. The possible range here is referred to as the passive displacement range. In particular, this may be greater than the active displacement range. Unless otherwise specified, the facet displacement range is understood to mean the maximum displacement range of the active displacement range and the passive displacement range, in particular the greater of the two.

[0023] According to one aspect of the invention, the total area of ​​the gaps between adjacent individual facets is in particular not more than 50%, in particular not more than 30%, in particular not more than 20%, in particular not more than 15%, in particular not more than 10%, in particular not more than 5%, in particular not more than 3%, in particular not more than 2%, in particular not more than 1% of the total area of ​​the reflective surfaces of the facet mirror or of all the individual facets of the facet mirror.

[0024] In particular, the individual facets have one, two, three or more degrees of freedom of displacement. In particular, the individual facets have two degrees of freedom of tilt. In particular, the individual facets may be tiltable, in particular about two tilt axes extending perpendicular to each other. The individual facets may also be linearly displaceable, in particular in a direction parallel to the surface normal at the center point of the reflective surface.

[0025] The individual facets, in particular the facet bodies thereof, may each be monolithically formed.

[0026] In this case, the component of the individual facet on which the reflection is provided is referred to as facet body. In particular, the facet body has a cross section that essentially corresponds to the reflective surface. The cross section of the facet body differs from the dimensions of the reflective surface of each facet by, in particular, not more than 30%, in particular not more than 20%, in particular not more than 10%.

[0027] In particular in the case of projection, in particular in the case of parallel projection, in particular in the case of orthogonal projection, the facet body has a cross section in the direction of the surface normal of the reflective surface, in particular in a region of the abutment surface and / or in a region of the abutment element in a direction perpendicular to the surface normal of the reflective surface of each individual facet, which cross section differs from the dimensions of the reflective surface of each facet by no more than 30%, in particular no more than 20%, in particular no more than 10%. This may in particular be a rectangular, in particular elongated cross section. The cross section may have straight or curved boundaries. The aspect ratio of this cross section of the facet body corresponds in particular to the aspect ratio of the reflective surface of each individual facet within the above-mentioned maximum difference. In this respect, reference is made to the following explanation.

[0028] The individual facets may also have other components, such as actuator devices for displacing the respective facets and / or the elements supporting the facets. Any such elements whose cross section differs significantly from the reflective surface, in particular by more than 50%, are not considered to be components of the facet body.

[0029] The individual facets, and in particular their reflective surfaces, are preferably elongated. They preferably have an aspect ratio (maximum longitudinal dimension:maximum perpendicular, i.e., lateral dimension) of 3:1 or more, in particular 5:1 or more, in particular 8:1 or more, in particular 10:1 or more, in particular 12:1 or more. The aspect ratio is preferably 100:1 or less, in particular 50:1 or less, in particular 30:1 or less, in particular 20:1 or less.

[0030] According to yet another aspect of the invention, the abutment surface which contacts the individual facet at a particular displacement position is formed by another individual facet, in particular by its body, in particular by a predetermined region of the body, or by a separate abutment element.

[0031] The facet mirror may be specially formed so that two adjacent individual facets can only come into contact when a non-actuable degree of freedom is excited, such deflection of the individual facets being possible in the case of earthquakes or transport loads, for example.

[0032] Contact with separate abutment elements can also limit the excitation of degrees of freedom that cannot be actuated, especially in the case of earthquakes or transport loads.

[0033] In accordance with yet another aspect of the present invention, the facet bodies of the individual facets are each shaped so that adjacent individual facets contact at a particular deflection or displacement location in a predetermined region of the facet body.

[0034] In particular, based on the intended displacement range of the individual facets and the geometrical configuration of the facet body, it is possible to predetermine the area in which contact with adjacent individual facets may occur, thereby making it possible to specifically adapt this intended area to possible collisions.

[0035] Preferably, the areas of the facet body where contact can occur are far from the reflective surface of each individual facet, in particular from their edges, thereby reducing the risk of damage to the reflective surface, in particular to its edges, due to collisions between adjacent individual facets, especially in the case of unexpected, in particular unpredictable, collisions such as may occur, for example, during transport of the facet mirror and / or in the event of an earthquake.

[0036] A predetermined area of ​​the facet body forms in particular an abutment surface.

[0037] According to yet another aspect of the invention, the facet bodies are formed such that the distance between the facet bodies of two adjacent individual facets is less than the distance between their reflective surfaces.

[0038] This property is particularly true for the base position of the individual facets. It is preferably true generally regardless of the displaced position of the individual facets. The corresponding form of the facet body is explained in more detail below.

[0039] According to yet another aspect of the invention, one or more abutment elements are provided on each facet body.

[0040] The abutment elements act as buffers, in a sense they act as bumpers, and allow for targeted definition of the areas where adjacent individual facets can come into contact with one another, and in particular for targeted definition of the abutment surfaces.

[0041] The abutment elements can be formed as separate elements and connected respectively to the facet body, in particular the abutment elements can be connected to the facet body in a form-fitting manner.

[0042] According to one aspect of the invention, the abutment element is connected to the facet body by gluing, soldering, welding, screwing, clamping, shrink fitting or slip-fitting. In principle, all conceivable connection techniques are possible for connecting the abutment element to the facet body.

[0043] In particular, the abutment element can be replaceable. The abutment element can also be formed integrally with the facet body, which allows for a particularly simple and stable production. The abutment element is preferably arranged at a predetermined position, in particular in the region of a peak, corner, edge or other predetermined position of the facet body.

[0044] The abutment element may extend over the entire width and / or length of the facet body. In particular, the abutment element may extend over the entire circumference of the facet body. Alternatively, it is possible to provide several abutment elements, each having a smaller size. This allows for a weight saving, which has a positive effect on the mechanical properties of the individual facets.

[0045] It is particularly conceivable to arrange one or more abutment elements at the ends of the facet body, in particular in the longitudinal end region thereof. It is also possible to arrange one or more abutment elements in a central region of the facet body, in particular in the longitudinal central region. This may be particularly advantageous in the case of curved facets.

[0046] The abutment elements may be provided in particular in the areas where collisions are most likely to occur. In particular, the abutment elements may be arranged in the areas where the distance between each facet body and the adjacent facet body is smallest. This description may relate to the position of the facet body in a neutral, i.e. undeflected, base state and / or to the displaced position of the adjacent facet bodies where the distance between them is smallest.

[0047] The abutment elements can be made of the same material as the facet body. In particular, they can be made of copper or a copper alloy. They can also be made of or consist of other materials. Other possible materials for the abutment elements are, for example, Zerodur, ULE, aluminum, ceramic, quartz, and silicon.

[0048] The abutment elements can be provided with a coating, in particular a water-resistant coating, as a result of which particle wear can be reduced, in particular prevented.

[0049] According to yet another aspect of the invention, the abutment element projects laterally from the reflective surface, in particular when viewed from above, and in particular laterally from the reflective surface.

[0050] The abutment element has a dimension in a direction parallel to the reflecting surface that is greater than the dimension of the reflecting surface in this direction.The abutment element has a dimension in a direction parallel to the width of the reflecting surface that is greater than the width of the reflecting surface.

[0051] In this way, damage to the reflecting surface in the event of a collision can be effectively and reliably prevented.

[0052] According to yet another aspect of the invention, the abutment element protrudes from the facet body in a direction opposite to the surface normal of the reflective surface, in particular on a side of the facet body opposite the reflective surface.

[0053] The abutment element may have a dimension in a direction parallel to the surface normal of the reflecting surface that is smaller than the dimension of the facet body in this direction.

[0054] According to yet another aspect of the invention, all of the individual facets of the facet mirror have identical abutment elements and / or abutment elements in essentially the same position, respectively.

[0055] This simplifies the manufacturing of the individual facets and the programming of the facet contours.

[0056] Alternatively, different individual facets may have different abutment elements and / or abutment elements at different positions. It is in particular possible to provide each individual facet with one or more abutment elements individually. This allows for greater flexibility in the planning of the facets.

[0057] The similarities and / or differences of the abutment elements here may relate respectively to the shape and / or arrangement of each individual facet.

[0058] According to yet another aspect of the invention, the abutment element is sized to extend over the entire length of the individual facet. The abutment element may in particular extend over the entire periphery of the individual facet.

[0059] As a result, the individual facets are particularly well protected.

[0060] According to yet another aspect of the invention, the individual facet, in particular its body, comprises a weight-reducing means and / or a weight-reducing form.

[0061] In particular, bores, clearances, pockets, thinned sections or bevels can act as weight saving means.

[0062] According to yet another aspect of the invention, the facet mirror comprises one or more means for limiting the range of displacement of the individual facets. The facet mirror may in particular comprise one or more means for limiting undesired deflections, in particular for limiting parasitic movements of the individual facets.

[0063] In this case, the means for limiting the displacement range, in particular the means for limiting undesired parasitic movements of the individual facets, may form the abutment surface.

[0064] The means for limiting the displacement range of the individual facets can be formed as snubbers, forks, pockets or pins also called U-profiles.

[0065] The play of each abutment surface is preferably less than the facet gap for adjacent individual facets.

[0066] According to yet another aspect of the invention, the free end of the means for limiting the displacement range of the individual facet is arranged in the region of the axis of rotation. As a result, the play of the individual facet around the means for limiting the displacement range of the individual facet can be reduced. In particular, this does not reduce the available play of the individual facet as a result of its movement around the axis of rotation.

[0067] To further reduce the play, it may be envisaged to adjust the means for limiting the displacement range of the individual facets.

[0068] It may in particular be envisaged to measure the gaps between the individual facets and / or to determine special spacers and place them on the facets and / or to make the abutments adjustable or configurable.

[0069] A further object of the invention is to improve the individual facets of a facet mirror of an illumination optical unit, in particular of a projection exposure apparatus according to the preceding description.

[0070] This object is achieved by an individual facet which comprises a facet body and a reflecting surface provided thereon, and one or more abutment elements provided on the facet body.

[0071] The advantages are clear from what has already been described.

[0072] According to one embodiment, the facet body is provided with one or more abutment surfaces and / or abutment elements which project from the reflecting surface in at least one direction perpendicular to the surface normal in projection in the direction of the surface normal of the reflecting surface.

[0073] Here, the surface normal is particularly a surface normal that passes through the center of gravity of the reflecting surface.

[0074] According to one embodiment, the individual facet has one or more abutment surfaces and / or abutment elements that project from the reflecting surface in at least one direction perpendicular to the surface normal of the reflecting surface and in both the opposite direction.

[0075] According to one embodiment, the individual facet has one or more abutment surfaces and / or abutment elements that protrude from the reflecting surface over the entire circumference of the reflecting surface in projection in the direction of the surface normal of the reflecting surface.

[0076] The abutment element can be a special form of the facet body, in particular a thickened portion thereof, which body is preferably at least partially wider than the reflective surface of the individual facet.

[0077] The abutment element can also be a separate component connected to the facet body.

[0078] The reflective surfaces of the individual facets may be flat. The reflective surfaces may have positive or negative refractive power. The reflective surfaces may also be toric.

[0079] The reflective surfaces of the individual facets may in particular be rectangular, trapezoidal or curved, in particular in the form of segments of circular rings.

[0080] According to yet another aspect of the invention, the facet body has at least one free end, in particular two free ends, and is formed such that its cross section decreases towards the free ends.

[0081] The cross section of the facet body in particular at least partially decreases from the attachment region towards the free end.

[0082] The cross section may decrease in particular continuously, in particular monotonically, towards the free end, which may reduce the mass moment of inertia. The cross section of the facet body may also contribute to increasing the stiffness of the facet body.

[0083] The cross section may also be enlarged again at the outer edge in the region of the free end, in which the facet body may in particular have an abutment element.

[0084] According to yet another aspect of the invention, the facet body comprises means for reducing its mass moment of inertia and / or means for increasing its stiffness.

[0085] Clearance, bore, or generally lighter configuration of the facet body may act as a means to reduce the mass moment of inertia of the facet body.

[0086] The profiled form may serve as a means for increasing the stiffness of the facet body. The facet body may in particular have an at least partially T-, U- or H-shaped cross section. The facet body may also be additively manufactured. In particular, the facet body may have a hollow structure. This may in particular effectively reduce the mass moment of inertia of the facet body.

[0087] It is yet another object of the present invention to provide an improved illumination optical unit of a projection exposure apparatus, an illumination system of a projection exposure apparatus, an optical system of a projection exposure apparatus, and a projection exposure apparatus. These objects are achieved by an illumination optical unit, an illumination system, an optical system, and a projection exposure apparatus having a facet mirror according to the above description.

[0088] The embodiment according to the invention provides particularly high protection, especially of the optical surfaces, during transport and in the case of seismic loads.

[0089] The advantages are seen from faceted mirrors.

[0090] It is yet another object of the present invention to improve methods for manufacturing microstructured or nanostructured components and the corresponding manufactured components.

[0091] These objects are achieved by providing a projection exposure apparatus according to the above description.

[0092] Further advantages are seen from faceted mirrors, see here.

[0093] Further advantages and details of the invention will become apparent from the description of exemplary embodiments with reference to the drawings. [Brief explanation of the drawings]

[0094] [Figure 1] 1 shows a schematic representation of the components and beam path of a projection exposure apparatus; [Figure 2] 2 shows a schematic diagram of an exemplary arrangement of field facets of a field facet mirror; [Figure 3] 1 shows a schematic representation of an actuator device for displacing a field facet about two independent tilt axes. [Figure 4] 1 shows a schematic representation of an actuator device for displacing a field facet about two independent tilt axes. [Figure 5] 10 shows further details schematically to clarify the relative position of the tilt axis of the field facet with respect to the reflective surface of the field facet. [Figure 6] The collision of two adjacent facets during rotation about an axis parallel to their surface normal is shown schematically as an example. [Figure 7] A perspective view of an individual facet is shown as an example. [Figure 8]The cross section of the abutment element protecting the facet is shown as an example. [Figure 9] The side view of the facet shown in FIG. 7 with two abutment elements arranged at the end is shown as an example. [Figure 10] 7 shows diagrammatically the view shown in FIG. 6, in which the facets are protected by abutment elements. [Figure 11] 1 shows a schematic diagram illustrating different tilt situations of two adjacent facets. [Figure 12] 1 shows a schematic diagram illustrating different tilt situations of two adjacent facets. [Figure 13] 1 shows a schematic diagram illustrating different tilt situations of two adjacent facets. [Figure 14] 10 shows a schematic representation of the arrangement of the abutment elements of the facets. [Figure 15] 10A and 10B show schematic views of alternative arrangements of the abutment elements of the facets; [Figure 16] A perspective view of a structurally optimized facet is shown as an example. [Figure 17] 1 shows a schematic partial perspective view of a facet having a body with means for reducing the mass moment of inertia and means for increasing stiffness; [Figure 18] 1 shows a schematic perspective view of a facet with a balance element. [Figure 19] 10 shows, by way of example, a detailed view of the arrangement of exemplary abutment elements on the body of the facet. [Figure 20] An example of the boundary of the abutment element is shown below. [Figure 21] An example of the boundary of the abutment element is shown below. [Figure 22] An example of the boundary of the abutment element is shown below. [Figure 23] 10A and 10B show diagrammatically views of facets with separate abutment elements for limiting the displacement range of the facets; [Figure 24] 24 shows a schematic cross section of adjacent facets with abutment elements as shown in FIG. 23; [Figure 25]24 shows a schematic longitudinal cross section of a facet to illustrate the preferred arrangement of the abutment elements shown in FIG. 23 relative to the tilt axis of the facet. [Figure 26] A variant in which the abutment elements are formed as separate lateral abutments is shown diagrammatically by way of example. [Figure 27] 10 shows, by way of example, yet another cross section of an abutment element protecting a facet. [Figure 28] A perspective view of a facet with three abutment elements is shown as an example. DETAILED DESCRIPTION OF THE INVENTION

[0095] In the following, the overall structure and beam path of a projection exposure apparatus 1 will first be described with reference to FIG.

[0096] The projection exposure apparatus 1 comprises an illumination optical unit 1a, which illuminates an object field 2 in an object plane 3 with illumination radiation 4. The projection exposure apparatus 1 also comprises a projection optical unit 1b, which images a reticle, not shown in Figure 1, arranged in the region of the object plane 3 and having a structure that is imaged onto a wafer, also not shown in Figure 1, arranged in an image plane 31. Details are widely known from the prior art.

[0097] The illumination radiation 4 may in particular be EUV radiation, in particular illumination radiation having a wavelength of less than or equal to 30 nm, in particular less than or equal to 13.5 nm.

[0098] The illumination radiation 4 is generated by a radiation source 5. A plasma source or a free electrode laser (FEL) can serve as the radiation source 5. For further details, please refer again to the prior art.

[0099] The combination of the illumination optical unit 1a and the radiation source 5 is also referred to as an illumination system 1c.

[0100] The illumination radiation 4 emitted by the radiation source 5 is collected by the collector 6. The collector 6 reflects the illumination radiation 4 towards subsequent components of the illumination optical unit 1a.

[0101] In the beam path after the collector 6, the illumination radiation 4 is incident on a first optical element in the form of a first facet mirror 7, also called a field facet mirror, which serves to generate a secondary light source in the illumination system 1c.

[0102] The total reflection surface of the first facet mirror 7, which is acted upon by the illumination radiation 4, is provided with a plurality of first facets 8, also called field facets. i 1 and 2 show four first facets 81 to 84 schematically.

[0103] Partial beam 12 of illumination radiation 4 i 1. Partial bundles 121 to 124 of illumination radiation 4, in particular allocated to the four first facets 81 to 84 shown, are likewise shown diagrammatically by way of example in FIG.

[0104] The first facet is usually elongated in shape. The first facet may be rectangular. The first facet may also be curved, in particular in the shape of a segment of a circular ring.

[0105] The first facets may all have the same dimensions. It is also possible to form first facet mirrors 7 with first facets of different dimensions.

[0106] The first facet may have an aspect ratio of, in particular, 5:1 or more, in particular 8:1 or more, in particular 12:1 or more, in particular 13:1 or more. The aspect ratio of the first facet is in particular 100:1 or less, in particular 50:1 or less.

[0107] The shape of the first facet can in particular be adapted to the shape of the object field 2. It can in particular be geometrically similar to the shape of the object field 2. The shape of the first facet is in particular such that, during operation of the projection exposure apparatus 1, the illumination radiation 4 reflected from the first facet illuminates the object field 2 or a predetermined partial area thereof as precisely as possible.

[0108] Each of the first facets can be displaced, in particular tilted, to provide different illumination settings, and the first facets can be tilted, in particular about two axes perpendicular to each other.

[0109] The following description of the positional relationships uses a Cartesian (x, y, z) coordinate system, in which the first facet can be tilted about a tilt axis extending in the x direction and a tilt axis extending in the y direction, with the z axis being parallel or nearly parallel to the surface normal of each facet.

[0110] Actuators are provided for displacing the respective first facets, one of which, actuator 16, is representatively shown in Figure 1. Actuator 16 is connected by control line 18 to a central control device 19. Control device 19 is connected to all other actuators assigned to the first facets by corresponding control lines not shown in Figure 1.

[0111] For further details of the first facet, see US Patent Application Publication No. 2003 / 0086524, specifically FIGS. 7-14, which are incorporated by reference in their entirety.

[0112] A second optical element in the form of a second facet mirror 20 is arranged at the location of the second light source generated by the first facet mirror, i.e. in the image plane relative to the radiation source 5. The second facet mirror 20 is also called a pupil facet mirror, on which the illumination radiation 4 is incident via the first facet mirror 7.

[0113] The surface of the second facet mirror 20 that can receive the incident light is provided with a plurality of second facets 21. i 1 shows four of these second facets 211-214 as an example. Since the second facets 211-214 are each assigned to one of the first facets 8-11, a second light source is generated at the location of each of the second facets 211-214 that receives the incident light.

[0114] The second facet may also be tiltable by an actuator, as shown schematically in Figure 1. As an example of this, an actuator 25 assigned to the second facet 21 is shown in Figure 1. The actuator 25 is in signal connection with the control device 19 via the beamline 18.

[0115] A transmission optical unit 27 with further mirrors 28, 29 is arranged in the beam path after the second facet mirror 20. In this case, the illumination radiation 4 can be incident on mirror 28 at a small angle of incidence, for example at an angle of incidence less than 30°, while mirror 29 can be incident at oblique incidence, for example at an angle of incidence greater than 60°.

[0116] The above description of the projection exposure apparatus 1 should be understood as an example. Other embodiments of the illumination system 1c are also possible, as known from the prior art.

[0117] Further details of the facets are described below. Even though the following description and figures relate to the facets of the first facet mirror 7, the described embodiments are equally possible and advantageous for the facets of the second facet mirror 20.

[0118] FIG. 2 shows an example of a detailed plan view of the first facet mirror 7 from its surface.

[0119] As shown by way of example in FIG. 2, the facet mirror 7 has a number of facets 8 arranged adjacent to each other. i where the adjacent facets are i , 8 i+1 are respectively separated from one another by gaps 32. In the variant shown in Figure 2, the gaps 32 extend parallel to the x or y direction.

[0120] In order to keep the reflection losses as small as possible, the gap 32 is as narrow as possible. The gap width is in particular less than 1 mm. The gap width is determined by the distance between the facets 8 in the corresponding direction. iis particularly 50% or less, particularly 30% or less, particularly 20% or less, particularly 15% or less, particularly 10% or less, particularly 5% or less, particularly 3% or less, particularly 2% or less, particularly 1% or less of the size of the

[0121] Generally, preferably not more than 50%, in particular not more than 30%, in particular not more than 20%, in particular not more than 15%, in particular not more than 10%, in particular not more than 5%, in particular not more than 3%, in particular not more than 2%, in particular not more than 1% of the total area of ​​the first facet mirror 7 is taken up by the gaps 32. The illumination radiation 4 cannot be reflected by the gaps 32. The gaps 32 therefore lead to transmission losses.

[0122] On the other hand, gap 32 is facet 8 i This is necessary to allow for a certain operating range.

[0123] Figures 3 and 4 show facet 8 i 1. The details of the actuator 16 for displacing the facet 8 are shown diagrammatically and by way of example. The actuation is effected by a lever 33. This can be achieved by magnetic forces. A magnet is located in particular on the underside of the lever 33, beneath which current-carrying coils are provided, which deflect the lever and as a result displace the facet 8. i The actuator 16 may also have one or more restoring elements in the form of, for example, leaf springs 34.

[0124] Facet 8 i Each of the facets 35 and 36 has a facet body 35 and a reflective surface 36. The reflective surface 36 has a peripheral edge 40.

[0125] Facet 8 i may be attached to a common frame or a common plate. i can also be mounted in groups on a modular plate.

[0126] The reflecting surface 36, also generally referred to as the optical surface, can be flat. However, it can also be curved. It can be particularly formed concave or convex. It can also be toric or have any other shape.

[0127] As shown by way of example in FIG. 5, the tilt axis 37 can be in the area of ​​the reflecting surface 36 (left side of FIG. 5). The tilt axis 37 can also be below, i.e., behind, the reflecting surface 36 (center of FIG. 5). The tilt axis 37 can also be above, i.e., in front of, the reflecting surface 36 (right side of FIG. 5). The position of the tilt axis 37 relative to the reflecting surface 36 depends on the position of the adjacent facet 8. i , 8 i+1 This influences the required width of the gap 32 to ensure that there are no collisions at a specified tilt angle range (tilt range).

[0128] The facet body 35 may preferably have at least partially a cross section that decreases in the direction perpendicular to the reflecting surface 36, for example a trapezoidal cross section. The side angle b may in particular be of the same order as the maximum set tilt angle; it may also be larger. The dimensions of the facet body 35, in particular its mass moment of inertia, can be reduced by increasing the side angle b of the facet body 35, in particular by making the bevel larger.

[0129] Depending on the mounting method, 8 individual facets i may have a low natural frequency that is excited, for example, during transportation or in case of unexpected shocks such as earthquakes. i , 8 i+1 This can lead to conflict between

[0130] 6 shows, as an example, a collision between two adjacent facets during rotation about the z-axis, which extends parallel to the surface normal on the center point of the reflective surface 36. Such a collision can lead to a depression of the optical edge, i.e., peripheral region, of the reflective surface 36.

[0131] Facet 8 i , 8 i+1 can be tilted about the x-axis and y-axis by the controller, but rotation about the z-axis is undesirable in normal operation of the projection exposure apparatus 1. However, such rotation about the z-axis can be excited during transportation and in the event of an earthquake. This is because facet 8 i , 8 i+1 This can lead to damage and should preferably be avoided.

[0132] 8 adjacent facets i , 8 i+1 Different concepts for avoiding, and in particular preventing, collisions are known from the prior art. Such concepts are usually complicated. Their effectiveness has also proven in many cases to be insufficient.

[0133] According to the present invention, these problems are solved by the optical component, in particular the facet 8 i The problem is solved by making it possible to control the collision of the facet body 35 and the reflecting surface 36. Here, according to the present invention, it is envisaged to form the facet body 35 and the reflecting surface 36 so that the reflecting surface 36 is not damaged in the event of a collision. This is because each facet 8 i This can in particular be achieved by providing the facet body 35 with a defined abutment surface that is arranged at a distance from the reflective surface 36 of the facet body 35 and in which area contact can occur. As will be explained in more detail below, a separate abutment element against which the facet body 35 can abut can also serve as the abutment surface.

[0134] The abutment surfaces may in particular be formed by predetermined areas of adjacent facets or by additional mechanical components.

[0135] The distance between the facet body and each associated abutment surface is in particular smaller than the width of the gap 32 in the corresponding direction. The distance between the facet body 35 and the associated abutment surface is in particular smaller than the distance between the reflective surface 36 and the abutment surface or the reflective surface 36 of an adjacent facet. This ensures that in the event of a collision, it is the desired abutment area that is hit and not the optical edge, i.e. the edge of the reflective surface 36.

[0136] Figure 7 shows facet 8 i A perspective view of the above is shown as an example.

[0137] In the variant shown in Figure 7, abutment elements 38 are provided at the ends of the facet body 35. A side view of the facet shown in Figure 7 is shown by way of example in Figure 9.

[0138] 8 shows in detail a cross section of the abutment element 38. The abutment element 38 has in particular an abutment edge 39. The abutment edge 39 is offset outward relative to an edge 40 of the reflecting surface 36 in a direction perpendicular to the tilt axis 37.

[0139] A cross section of a variant of the abutment element 38 is shown in Figure 27. The abutment element 38 according to Figure 27 has shoulders 48 on both sides of the reflective surface 36. The shoulders 48 extend in particular in a direction parallel to the width of the facet. This leads to improved protection of the reflective surface 36, in particular its edge 40.

[0140] Intermediate steps between the configuration of the abutment element 38 shown in Figure 27 and the embodiment shown in Figure 7 are likewise possible. The shoulder 48 may be oriented at an angle c in the range of 90° to 150°, in particular in the range of 90° to 135°, preferably greater than or equal to 100°, relative to the vertical direction 49, where the vertical direction 49 extends parallel to a surface normal 50 passing in particular through a centre point 51 of the reflecting surface 36.

[0141] The abutment edge 39 may be radiused or chamfered.

[0142] 9, the abutment element 38 projects downward from the facet body 35, i.e., from the side opposite the reflective surface 36 of the facet body 35. This vertical overhang is i The desired tilt range of facet 8 can be determined based on the i The tilt range may be, for example, 100 mrad or less.

[0143] The abutment elements 38 can be plate-shaped. The abutment elements 38 can also be sleeve-shaped, which allows them to be fitted onto the facet body 35.

[0144] The abutment elements 38 may be arranged at the free ends of the longitudinal facet bodies 35, respectively.

[0145] The abutment element 38 can also surround the longitudinally free end of the facet body 35 on three sides. A corresponding configuration is shown by way of example in Figure 10. Such a configuration of the abutment element 38 ensures that the facet 8 is securely attached to the abutment element 38, especially in the case of a collision due to a rotation about the z-axis. i , 8 i+1 , and in particular its reflective surface 36.

[0146] The abutment element 38 is i It is preferred that the facet body 36 is formed and / or arranged in such a way that in any tilt position, in particular in any operating switching position, even around the z-axis, any particularly accidental excitation will cause a collision, if any, but only in the region of the abutment element 38 and not in the region of the edge 40 of the reflecting surface 36.

[0147] As shown by way of example in FIG. 28, the abutment elements 38 can also be arranged in the central region of the facet body 35. This is particularly useful for curved facets 8 i This can be advantageous in cases where

[0148] The abutment elements 38 are preferably located in one or more areas where the distance between each facet body 35 and an adjacent facet body 35 or adjacent abutment element 38 is minimal. The abutment elements 38 are particularly located in areas of the facet body 35 where collisions are most likely to occur.

[0149] As shown by way of example in FIG. 28, the abutment elements 38 arranged in the region of the free end of the facet body 35 do not have to be arranged completely at the end of the facet body 35 either.

[0150] As shown by way of example in Fig. 28, the different abutment elements 38 may have different geometric forms. In particular, the abutment elements 38 arranged in the central region of the facet body 35 may be formed differently from the abutment elements 38 arranged further towards the edges. In particular, the abutment elements 38 arranged in the central region of the facet body 35 may be formed such that their dimension in a direction perpendicular to the reflecting surface 36 is smaller than the dimension of the facet body 35 in this direction.

[0151] In particular, the abutment element 38 arranged in the central region of the facet body 35 can be formed as a thickened portion of the facet body 35 .

[0152] The abutment elements 38 arranged in the central region of the facet body 35 can be arranged on only one side of the facet body 35. It is also possible to arrange corresponding abutment elements 38 on two sides, in particular on both sides of the facet body 35.

[0153] By arranging the abutment element 38 in the region where the width of the gap 32 is particularly small, in particular at its smallest, it is possible to make the abutment element 38 particularly thin and therefore particularly light.

[0154] The abutment element 38 is i When displaced, and / or facet 8 i Due to the unexpected excitation of facet 8 i The reflecting surface 36 is specifically configured to allow contact with the abutment surface to occur such that the reflecting surface 36 contacts the abutment surface at a predetermined area spaced apart from the reflecting surface 36 .

[0155] Figures 11 to 13 show the adjacent facets 8 i , 8 i+1 1 shows examples of different configurations when tilted.

[0156] Facet 8 i , 8 i+1 are angled away from each other (FIG. 11), there is no or at least less danger to the adjacent edges 40.

[0157] In the opposite case, i.e., adjacent facet 8 i , 8 i+1 If the facets 8 are inclined towards each other, a collision can in principle occur. However, according to the invention, it is envisaged to form the abutment elements 38 in such a way that the abutment edge 39 of one abutment element 38 comes into contact with the other abutment element 38. In principle, the abutment element 38, and in particular its abutment edge 39, can be in contact with the adjacent facet 8. i It may also strike another area of ​​the facet body 35.

[0158] However, Facet 8 i The area where contact (collision) can occur is each facet 8 i It should be ensured that the light source is positioned away from the reflective surface 36 of the

[0159] As can be easily deduced from geometrical conditions, the ratio of the overhang e by which the abutment edge 39 projects laterally beyond the reflecting surface 36 to the height h of the reflecting surface 36 above the plane passing through the abutment edge 39 must, in the illustrated configuration of the abutment element 38, be at least as great as the tangent of three times the side angle b: e:h ≥ tan(3b). If the side angle b is 40 mrad, the following applies in particular: e:h ≥ 120 μm / mm. With such a configuration of the abutment element 38, the edge 40 of the reflecting surface 36 will be at the same height as the facet 8. i The vehicle is protected from collisions in all possible tilt positions.

[0160] This also applies in the case of an additional actuation about a second tilt axis, as shown by way of example in FIG. 13. In this case, this is mainly due to the actuation of two facets 8 in the z direction. i , 8 i+1 This leads to a relative displacement of the other facet 8 i However, in the illustrated form of the abutment element 38, the facet 8 i The edge 40 of the reflecting surface 36 is also protected by the abutment element so that it cannot collide.

[0161] 13, the size of the abutment element 38 in the z direction varies depending on the maximum tilt range around the y axis. A sufficient size of the abutment element 38 in the z direction can ensure that the abutment element 38 provides an abutment surface to protect the edge of the reflecting surface 36 from collisions, regardless of the tilt position around the y axis.

[0162] Regarding the preferred value of the overhang e of the abutment edge 39 beyond the reflecting surface 46, in particular in a direction parallel to the reflecting surface 36 or perpendicular to the respective tilt axis, the following factors may preferably be taken into account:

[0163] The manufacturing tolerance for the manufacture of the facet body 35 is typically in the range of 10 μm to 50 μm.

[0164] The abutment element 35 is located at the facet 8 i The abutment edge 39 may wear over its lifetime. In the event of a collision, there may be a maximum recession of the abutment edge 39 in the range of a few microns or less. This depends, inter alia, on the material of the abutment element 38 and / or the impact angle in the event of a collision. As will be explained in more detail below, it is possible to envisage making the abutment edge 39 radiused, which makes it possible to reduce the Hertzian pressure in the event of a collision.

[0165] Overhang e, especially facet 8 i Furthermore, the absolute value of the overhang e depends on the distance, in particular the height h, between the abutment edge 39 and the edge 40 of the reflective surface 36 to be protected. The smaller this distance or height h is, the smaller the overhang e that can be selected.

[0166] An overhang e in the range of 20 μm to 100 μm has been found to be particularly useful.

[0167] A smaller overhang e is advantageous to keep the distance between adjacent reflecting surfaces 36 as small as possible. i , 8 i+1 the distance between adjacent facet bodies 35 in the neutral position of the facets 8, in particular the distance between adjacent facet bodies 8 that are closest to each other. i , 8 i+1 The distance between the abutting edges 39 of the facets 8 is preferably less than 100 μm, in particular 50 μm or less. i , 8 i+1 This preferably applies to the distance between two adjacent reflecting surfaces 36 in their neutral position, or in particular in the position where the surface normals run parallel to one another.

[0168] A further embodiment of the present invention will now be described with reference to FIGS.

[0169] This aspect relates to the arrangement of the abutment elements 38 on the facet body 35. According to the invention, the constriction, i.e. the gap between two adjacent facets 8 i , 8 i+1 It is recognized that the points of minimum distance between adjacent facets 8 are not necessarily in the region of their free edges. i , 8 i+1 The nominal width of the gap 32 between the facets 8 i , 8 i+1 The length of the

[0170] Therefore, according to the invention, it is possible to envisage arranging the abutment elements 38 on the facet body 35 depending on the position of the constriction. The abutment elements 38 can in particular not only be arranged at the ends of the facet body 35. This is shown by way of example in Fig. 14 for facets 81, 82. However, the abutment elements 38 can also be arranged in the centre of the facet body 35. This is shown by way of example in Fig. 14 for facets 82, 83.

[0171] As an alternative to this, the amount of overhang e can be selected differently, as shown by way of example in Figure 15. Here, the overhang e of the abutment element 38 between facets 82 and 83 is selected to be greater than the amount of overhang e between facets 81 and 82. This also means that a small gap width in the central region of facets 82, 83 can be taken into account.

[0172] In other words, it is possible to flexibly select the position of the arrangement of the abutment elements 38 as required. Alternatively, the abutment elements 38 can be arranged at respective predetermined positions on the facet body 35. In this case, in particular, the amount of the overhang e can be flexibly adapted to the gap width.

[0173] All Facets 8 i The predetermined location of the abutment elements 38 on the facet body 35, which is the same as in the previous example, has the advantage of reducing the number of facet feature variations, which makes programming the facet contour easier.

[0174] According to yet another variant, the abutment edge 39 is connected to the facet 8 i It is envisaged that the abutment edge 39 is formed over the entire length of the facet body 35. The abutment edge 39 can in particular be formed over the entire circumferential area of ​​the facet body 35. The abutment edge 39 can be formed continuously here. It can also be formed intermittently. This allows for weight reduction.

[0175] In particular, for reasons of weight saving, it may be advantageous to arrange the abutment elements 38 only in critical areas of the facet body 35. In particular for relatively large tilt ranges, in particular tilt ranges above 40 mrad, it may be advantageous to arrange the abutment elements 38 only in critical areas of the facet body 35. i It may be advantageous to place it only in the region of the free end of the

[0176] The abutment elements 38 may in particular only be arranged at discrete locations in the longitudinal direction of the facet body 35. In particular, up to 10, in particular up to 8, in particular up to 6, in particular up to 4, in particular up to 2 abutment elements 38 may be arranged on the facet body 35. The abutment elements 38 may each have a size in the longitudinal direction of the facet body 35 of 10% or less, in particular 5% or less, in particular 3% or less, in particular 2% or less of the length of the facet body 35.

[0177] Generally, the abutment elements 38 may be formed and arranged on the facet body 35 such that the mass moment of inertia of the facet body 35 increases by no more than 10%, in particular no more than 5%, in particular no more than 3% due to the arrangement of the abutment elements 38.

[0178] A further aspect of the invention relates to an advantageous configuration of the facet body 35. It has been found that a facet that is as light as possible is advantageous for dynamic reasons. On the one hand, this keeps the amplitude low in the event of excitation, and on the other hand reduces the impact energy in the event of a collision. According to the invention, the facet 8 with the abutment surface i If contact is allowed, such conflicts will not be harmful, especially in facet 8. i Care must be taken to ensure that the material does not cause damage to the material or lead to particle formation.

[0179] Facet 8 of minimum weight, especially minimum mass moment of inertia with respect to the dynamically important axes, especially the tilt axis i In order to form the facet body 35, the facet body 35 can be formed with structural optimization.

[0180] The facet body 35 may have a means for reducing its weight, particularly its mass moment of inertia. To reduce the weight and mass moment of inertia of the facet body 35, it is possible, for example, to form the facet body 35 with a cross section that decreases toward the free end. In particular, it is possible to reduce the height of the facet body 35 toward the end of the facet. A corresponding configuration is shown by way of example in FIG. 16. The set angle W between the back side of the facet body 35 and its front side is preferably in the range of 2° to 10°, more preferably in the range of 4° to 6°. Due to the thin end configuration of the facet body 35, its mass moment of inertia can be reduced by approximately 10% compared to a non-optimized configuration. At the same time, the stiffness of the facet body 35 can be increased. This can be achieved by increasing the cross-sectional area, especially toward the facet support point. Because the cross section decreases toward the free end, the total mass of the facet body 35 increases, but the mass moment of inertia decreases. Therefore, the mass moment of inertia decreases over the entire length of the facet body 35, and stiffness increases. For example, by reducing the cross-sectional area of ​​the facet body 35 towards the edges, the dead load sag of the facet body 35 can be improved by more than a factor of two, and especially by more than a factor of three. These descriptions relate to a facet having an exemplary length of 120 mm, a width of 6.6 mm, and an average height of 14 mm.

[0181] Furthermore, the required stiffness can be displaced towards the actuator axis.

[0182] Another way to reduce the weight of the facet body 35, in particular its mass moment of inertia, is shown by way of example in Figure 17. According to this variant, a bore is provided in the facet body 35, which likewise leads to a reduction in weight. Alternatively or additionally, pockets can also be provided, in particular from the back side of the facet body 35 or from its lateral sides. Furthermore, a gradual reduction in cross section is also possible in other ways, for example by bevelling on both sides.

[0183] Yet another way of optimizing the facet body 35 is shown in Figure 18. According to this variant, the facet body 35 is mounted very asymmetrically: a balancing element 41 is now provided in the region of the shorter free end.

[0184] The mass moment of inertia of the facet body 35, especially around Rx, can be reduced by up to 30% by the measures described above.

[0185] The abutment elements 38 preferably have a small dimension in the x-direction, i.e. in the longitudinal direction of the facet body 35. The abutment elements 38 may in particular have a dimension in the x-direction in the range of 1 mm to 3 mm. For example, in the case of the facet 8 mentioned above as an example, i is approximately 180,000 g·mm, especially when combined with the other moving masses of the manipulator. 2 Total moment of inertia I yy The total additional moment of inertia I due to the abutment element 38 yy is 5000m·mm 2 , i.e., the total moment of inertia I yy This is less than 3% of the total.

[0186] According to yet another variant, the additional weight and therefore the moment of inertia brought about by the abutment element 38 can be further reduced by means of clearances, for example bores or pockets. Such a weight reduction can be introduced into the abutment element 38, in particular at the end faces in the x-direction. As a result, the facets 8 i Total moment of inertia I yy The relative proportion of the mass moment of inertia of the abutment element 38 in the shaft can be reduced to less than 2%.

[0187] The abutment element 38 is particularly adapted to protect the facet 8 in case of an unexpected excitation and / or impact. i , and in particular its reflecting surface 36. The abutment element 38 also protects the facets in particular in the case of seismic loads, where the excited vibration amplitude may be a multiple of the width of the gap 32 provided.

[0188] Further aspects of the invention are described below.

[0189] The abutment element 38 can be formed as a separate component. In particular, the abutment element 38 can be arranged on the facet body 35. The abutment element 38 is generally connected to the facet body 35. Essentially all conceivable connection techniques are possible here. The abutment element 38 can in particular be glued, soldered, welded, screwed, clamped or shrink-fitted, or fitted onto the facet body 35.

[0190] The form of the abutment element 38 as a separate component has the advantage that the abutment element 38 can be manufactured from a different material than the facet body 35. They can also be manufactured from the same material. In particular, they can be manufactured from copper or a copper alloy. This is advantageous, especially with regard to particle formation. Furthermore, manufacturing the abutment element 38 from copper or a copper alloy has the advantage that, as a result of the relatively low hardness of copper, in the event of a collision, only slight indentations occur at non-interfering points. Particle formation is largely prevented.

[0191] It is also possible to integrate the abutment element monolithically into the facet body 35. In particular, the abutment element can be formed integrally with the facet body 35. In this case, the abutment element 38 can be formed in particular by geometric details, in particular by the shape of the facet body 35. This allows for a particularly simple and robust production.

[0192] As shown by way of example in Figures 20 to 22, the shape of the abutment element 38, in particular its abutment edge 39, can be sharp (Figure 20), non-sharp, in particular tapered and flat (Figure 21), or rounded (Figure 22). A rounded, preferably chamfered, shape makes it possible to reduce the Hertzian stress. This represents a preferred embodiment.

[0193] Crash tests showed that after hundreds of impacts with normal impact energies, there was very little wear, especially indentations in the contact area of ​​less than 2 μm.

[0194] According to yet another variant, the height h, which the reflecting surface 36 is offset from the plane passing through the abutment edge 39 of the abutment element 38 in the direction of its surface normal, can be close to 0. This is because the facet 8 i This corresponds to the case where the used optical surface does not reach its geometric periphery, in particular does not reach the periphery of the facet body 35. Such a configuration also has the effect that the reflecting surface 36 is not struck in the event of a collision. However, in this case the reflecting surface 36 is surrounded by a peripheral area that is not used for reflecting the illumination radiation 4. As a result, the filling of the facet mirror 7 and therefore its efficiency in terms of transmission is reduced.

[0195] Further exemplary embodiments are described below with reference to Figures 23 to 25. For general details, please refer to the previous embodiments.

[0196] In this exemplary embodiment, the abutment surface is facet 8 i The tilting range is formed by a means for limiting the range of tilt of the facet body 35. According to the variant shown, a pin 42, also called a snubber, serves as such a means. The pin 42 enters a pocket 43 on the rear side of the facet body 35. The penetration depth is large enough to accommodate the entire tilting range. In principle, the pin 42 could also be tilted together with the facet body 35.

[0197] Pin 42 and facet 8 shown only in FIG. i The mountings 46 are arranged on a common base plate 47 .

[0198] Advantageously, the exact position of the pin 42, and in particular of its free end entering the pocket 43, can be adjustable.

[0199] The play between the pin 42 and the abutment surface 44 inside the pocket 43 is i , 8 i+1 smaller than the distance between two adjacent facets, especially i , 8 i+1 The play between the pin 42 and the abutment surface 44 is smaller than the portion of the gap 32 available for the T0 tolerance in particular. This ensures that the protective effect of the edge 40 of the reflecting surface 36 is ensured also in this variant.

[0200] In order to reduce the play around the pin 42, it is advantageous to form and / or arrange the pin 42 so that its free end extends in the region of the tilt axis 37 (x-axis in the illustrated case).

[0201] To further reduce the play, the pin 42 can be adjusted. The pin 42 can be specially made adjustable.

[0202] The pin 24 may be configured in particular with a spherical shape at its free end, which avoids interfering with the tilting of the facets.

[0203] In the illustrated embodiment, the snubber is shown as a pin 42. It is also conceivable that the snubber could be formed as a fork, i.e. with multiple free ends surrounding the facets.

[0204] According to yet another variant, shown by way of example in FIG. 25, lateral abutments 45 are provided instead of the pins 42 .

[0205] Generally, facet 8 iIt should be noted that the facet body 35 has a displacement range such that it contacts the abutment surface at a specific displacement position. The displacement position may be a reversibly operable displacement position. The displacement position may also be an undesired deflection position that may occur during transportation or in the event of an earthquake, particularly only during transportation or an earthquake but not during controlled deployment.

[0206] The abutment surface may here be formed by a surface of a further optical element, in particular a further facet body 35 or an abutment element 38 arranged thereon. It may also be formed by a separate mechanical detail, for example a pin or a lateral abutment 45.

[0207] Preferably, all abutment surfaces are made of a water-resistant material. The abutment surfaces may also have a water-resistant coating. This can prevent particles from being generated in the event of a collision. Any particles that are generated can be collected in a collection container or in pockets formed by adjacent components.

Claims

1. A facet mirror (7, 20) of an illumination optical unit (1a) of a projection exposure apparatus (1), 1.

1. Multiple displaceable individual facets (8 ｉ , 21 ｉ ) and 1.1.

1. A facet body (35); 1.1.

2. A reflecting surface (36) provided on the facet body (35); Individual facets (8 ｉ , 21 ｉ ) In a facet mirror (7, 20) comprising 1.

2. The individual facets (8 ｉ , 21 ｉ ) are adjacent individual facets (8 ｉ , 21 ｉ ) are formed so that they can come into contact with each other, but only in the area of ​​the abutment surfaces formed on the facet body (35) and / or in the area of ​​abutment elements (38) arranged or formed on the facet body (35), 1.

3. The facet body (35) is formed by two adjacent individual facets (8) in the region of the abutment surface and / or in the region of the abutment element (38). ｉ , 8 ｉ＋１ , 21 ｉ , 21 ｉ＋１ ) is formed so that the distance between the facet bodies (35) is smaller than the distance between the reflecting surfaces (36), 1.

4. A facet mirror characterized in that the abutment element (38) has a size in a direction transverse to and parallel to the reflecting surface (36) that is larger than the size of the reflecting surface (36) in said direction and / or protrudes from the facet body (35) on the side of the facet body (35) opposite to the reflecting surface (36).

2. A facet mirror (7, 20) of an illumination optical unit (1a) of a projection exposure apparatus (1), 2.

1. Multiple displaceable individual facets (8 ｉ , 21 ｉ ) and 2.1.

1. A facet body (35); 2.1.

2. A reflective surface (36) provided on the facet body (35); Individual facets (8 ｉ , 21 ｉ ) In a facet mirror (7, 20) comprising 2.

2. The individual facets (8 ｉ , 21 ｉ at least some of the bearings have a displacement range such that they contact the abutment surface at one or more displacement positions; 2.

3. The facet body (35) is divided into two adjacent individual facets (8) in the region of the abutment surface and / or in the region of the abutment element (38). ｉ , 8 ｉ＋１ , 21 ｉ , 21 ｉ＋１ ) is formed so that the distance between the facet bodies (35) is smaller than the distance between the reflecting surfaces (36), 2.

4. A facet mirror in which the abutment element (38) has a size in a direction transverse to and parallel to the reflecting surface (36) that is larger than the size of the reflecting surface (36) in said direction and / or protrudes from the facet body (35) on the side of the facet body (35) opposite to the reflecting surface (36).

3. 3. A facet mirror (7, 20) according to claim 1 or 2, wherein all individual facets (8 ｉ , 21 ｉ ) is located away from all abutment surfaces in the respective home position and / or active displacement position.

4. A facet mirror (7, 20) according to any one of claims 1 to 3, wherein the individual facets (8) ｉ , 21 ｉ ) are adjacent individual facets (8 ｉ , 8 ｉ＋１ , 21 ｉ , 21 ｉ＋１ 10. A facet mirror having a displacement range such that the facet mirror contacts the surface of the facet mirror at one or more displacement positions.

5. A facet mirror (7, 20) according to any one of claims 1 to 4, wherein the individual facets (8) ｉ , 21 ｉ ) at least some of the adjacent individual facets (8 ｉ , 8 ｉ＋１ , 21 ｉ , 21 ｉ＋１ ) is formed so as to be able to come into contact with the surface in a predetermined contact area.

6. A facet mirror (7, 20) according to any one of claims 1 to 5, wherein the abutment surfaces are arranged on the individual facets (8). ｉ , 21 ｉ ) or formed by separate abutment elements (38) on the facet body (35).

7. A facet mirror (7, 20) according to any one of claims 1 to 6, characterized in that one or more abutment elements (38) are respectively provided on the facet body (35).

8. 8. A facet mirror (7, 20) according to claim 1, characterized in that the abutment elements (38) are arranged in pairs on the facet body (35) in such a way that their outer envelopes project beyond the reflecting surface (36) in at least one direction in perpendicular projection onto a partial area of ​​the reflecting surface (36) enclosed by the outer envelope.

9. A facet mirror (7, 20) according to any one of claims 1 to 8, wherein the individual facets (8) ｉ , 21 ｉ ) a facet mirror characterized by one or more means for limiting the range of displacement of said facet mirror.

10. An individual facet (8, 21) of a facet mirror (7, 20) of an illumination optical unit (1a) of a projection exposure apparatus (1), 10.

1. A facet body (35); 10.

2. A reflecting surface (36) provided on the facet body (35); In the individual facets (8, 21) having 10.3 An individual facet, characterized in that the facet body (35) is provided with one or more abutment surfaces and / or abutment elements (38) which, when projected in the direction of the surface normal of the reflecting surface, protrude beyond the reflecting surface (36) in at least one direction perpendicular to the surface normal.

11. 11. An individual facet (8, 21) according to claim 10, characterized in that the individual facet (8, 21) has one or more abutment surfaces and / or abutment elements (38) which, when projected in the direction of the surface normal of the reflecting surface, protrude from the reflecting surface (36) in at least one direction perpendicular to the surface normal and in both the opposite direction.

12. 12. An individual facet (8, 21) according to claim 10 or 11, characterized in that the individual facet (8, 21) has one or more abutment surfaces and / or abutment elements (38) that protrude from the reflecting surface (36) over the entire circumferential area of ​​the reflecting surface (36) when projected in the direction of the surface normal of the reflecting surface.

13. An individual facet (8, 21) according to any one of claims 10 to 12, characterized in that the projection is a parallel projection.

14. An individual facet (8, 21) according to any one of claims 10 to 13, characterized in that the projection is an orthogonal projection.

15. An individual facet (8, 21) according to any one of claims 10 to 14, characterized in that at least some of the facet bodies (35) and / or the abutment elements (38) have a size in a direction transverse to and parallel to the reflecting surface (36) that is greater than the size of the reflecting surface (36) in said direction.

16. An individual facet (8, 21) according to any one of claims 10 to 15, characterized in that at least some of the abutment elements (38) protrude from the facet body (35) in at least one direction opposite the reflective surface (36) of the facet body (35).

17. 17. An individual facet (8, 21) according to any one of claims 10 to 16, characterized in that at least some of the abutment elements (38) are arranged in pairs on the facet body (35) such that their outer envelopes project beyond the reflecting surface (36) in at least one direction in a perpendicular projection onto a partial area of ​​the reflecting surface (36) surrounded by the outer envelope.

18. An individual facet (8, 21) according to any one of claims 10 to 17, characterized in that the facet body (35) has at least one free end, the cross section of the facet body (35) decreasing towards said free end.

19. An individual facet (8, 21) according to any one of claims 10 to 17, characterized in that the facet body (35) comprises a bore.

20. An individual facet (8, 21) according to any one of claims 10 to 17, characterized in that the facet body (35) has a pocket.

21. Illumination optical unit (1a) comprising at least one facet mirror (7, 20) according to any one of claims 1 to 9.

22. An illumination system (1c) of a projection exposure apparatus (1), 22.

1. An illumination optical unit (1a) according to claim 21, 22.

2. A radiation source (5) generating illumination radiation (4) and A lighting system equipped with

23. An optical system of a projection exposure apparatus (1), 23.

1. An illumination optical unit (1a) according to claim 21, 23.

2. A projection optical unit (1b) for projecting the object field (2) into an image field; An optical system comprising:

24. A projection exposure apparatus (1), 24.

1. A radiation source (5) for generating illumination radiation (4), 24.

2. An illumination optical unit (1a) according to claim 21, 24.

3. A projection optical unit (1b) for projecting the object field (2) into an image field; A projection exposure apparatus comprising:

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