Optical element, and assembly and optical system thereof

Abstract

An optical element (OE) incorporated into a holding device forming a component (BG) for constituting an optical system (PO) comprises a body (K) which is transparent to light of the wavelength range used on which a first optical channel surface (LF1) and an opposite second optical channel surface (LF2) are formed. Each of the optical channel surfaces (LF1, LF2) has: an optical use area (NB1, NB2) provided for arrangement in a use beam path of the optical system; and an edge region (RB1, RB2) located outside the optical use region and designated as a joining region for a holding element (HE) of a holding device. Each optical channel surface is prepared to optical quality in an optical use area (NB1, NB2) and has a surface shape designed according to a use area specification specified using an optical element (OE) function in the beam path. A light deflection structure (LUS1) having a geometrically defined surface design is formed in an edge region (RB1) of at least one of the light channel faces (LF1) and is designed according to an edge region specification deviating from the use region specification and is configured to deflect a portion of the light deflected by the light deflection structure into a target region (ZB) outside the use beam path.

Description

[0001] The following disclosure is based on German patent application No. 10 2022 205143.2 filed on May 24, 2022, which is incorporated into the present application by reference. Technical Field

[0002] The invention relates to an optical element incorporated into a holding device to form a component for forming an optical system for a microlithography projection exposure device, a component containing an optical element and a holding device for holding the optical element, and an optical system having at least one optical element.

[0003] A preferred field of application is optical imaging systems for forming projection exposure apparatuses for microlithography, in particular in the form of refractive or catadioptric microlithography projection lenses. Background Art

[0004] Today, microlithography projection exposure methods are mainly used for the production of semiconductor components and other fine structured components. In this context, a mask (photomask, reticle) is used, which carries or forms a pattern of the structure to be imaged, for example a line pattern of a semiconductor component layer. In a projection exposure device, the mask is positioned in the beam path between the illumination system and the projection lens so that the pattern is located in the region of the object plane of the projection lens. The substrate to be exposed, for example a semiconductor wafer coated with a radiation-sensitive layer (resist, photoresist), is held so that the radiation-sensitive surface of the substrate is arranged in the region of the image plane of the projection lens optically conjugate with the object plane. During the exposure process, the pattern is illuminated by means of an illumination system, which forms an illumination radiation directed at the pattern from the radiation of a primary radiation source, characterized by specific illumination parameters, and incident on the pattern within an illumination field of defined shape and size. The radiation modified by the pattern passes as projection radiation through the projection lens, which images the pattern onto the substrate to be exposed, which is coated with the radiation-sensitive layer. For example, microlithography projection exposure methods can also be used for the production of masks (reticles).

[0005] One of the goals in the development of projection exposure apparatuses is to produce lithographically etched structures on substrates of increasingly smaller dimensions. In the case of semiconductor components, for example, smaller structures lead to a higher integration density, which is generally beneficial for the performance of the microstructured components produced. The size of the structures that can be produced depends primarily on the resolution of the projection lens used and the resolution of the projection lens used can also be increased, firstly, by reducing the wavelength of the projection radiation used for projection and, secondly, by increasing the image-side numerical aperture NA of the projection lens used in the process.

[0006] Projection lenses are optical imaging systems that often contain multiple optical elements in order to meet partially conflicting requirements regarding the correction of imaging aberrations, possibly even when using large numerical apertures. In the field of microlithography, refractive or refracting imaging systems and catadioptric imaging systems often have 10 or more transparent optical elements.

[0007] The optical element is held at a defined position along the used beam path of the optical system using a holding device. In the case of an imaging system, the used beam path is generally referred to as the imaging beam path. The optical element of the imaging system that contributes to the imaging has an optically used area located in the imaging beam path and an edge area located outside the optically used area. In the optically used area, the refractive or reflective surface is prepared for optical quality. The surface shape is specified by the design parameters of the optical design of the imaging system according to the optical effect required by the optical element, the specification usually taking the form of polynomial coefficients of a polynomial defining the surface shape. In the specification table, the optically used area is also generally referred to as the "clear optical diameter" or "clear aperture" of the optical element. Optical quality does not need to be achieved in the edge area. When assembling components with lens elements and other transparent optical elements, the holding elements of the holding device assigned to the optical element are generally engaged on the edge area. Corresponding statements apply to optical elements in illumination systems, in which the used beam path is generally referred to as the illumination beam path.

[0008] Different options for fixing the optical element to the holding element have been proposed. Patent application US 2003 / 0234918 A1 discloses an example of a holding mounting technique, in which the optical element is held by elastic holding elements in the edge region (soft mounting). In other holding devices, the elastic holding elements of the holding device are bonded to the optical element in the correspondingly assigned contact regions using an adhesive layer. Examples of adhesive bonding techniques are disclosed in patent applications US 4,733,945 or US 6,097,536.

[0009] In practice, for optical imaging systems with complex structures, radiation not only reaches the image plane from the object along the imaging beam path required for imaging; on the contrary, radiation parts may also appear that do not contribute to the imaging but may interfere with the imaging or lead to a deterioration of the imaging. For example, in the case of projection exposure methods, so-called "super-aperture light" may lead to a deterioration of the imaging quality. In this context, the term "super-aperture light" means light that is diffracted by the mask that imparts the structure and is emitted at an object-side aperture angle greater than the object-side aperture angle used for imaging, which is determined by the current diameter of the aperture stop that defines the imaging beam path. Super-aperture light does not contribute directly to the imaging because it cannot pass through the aperture stop to the image plane. However, it heats the optical elements located between the mask and the aperture stop. The result of this heating is a change in the refractive index and the shape of the lens elements, which in turn leads to a disturbance in the wavefront that contributes to the image generation. Alternatively or additionally, scattered light can also be generated, which, if it reaches the image plane, generally reduces the contrast of the generated image. In this case, the term "scattered light" refers in particular to light which may arise due to residual reflections at surfaces of transparent optical elements coated with antireflection coatings, for example, which are located behind mirrors and / or at other locations in the region of the imaging beam path. These unwanted light components at the wavelength specified for imaging, in particular scattered light and superaperture light, are also referred to as "stray light" within the scope of this application, regardless of their cause.

[0010] In addition to the inherent imaging aberrations which a projection lens may have due to its optical design and production, imaging aberrations may also arise during use, for example during operation of the projection exposure apparatus by a user. The cause of such imaging aberrations is often changes in the optical elements used in the projection lens, which are caused by the radiation used during use. For example, the optical elements in the projection lens may absorb some of this radiation. The extent of the absorption depends, among other things, on the materials used in the optical elements, such as lens element materials, mirror materials, and / or on the nature of any antireflection coatings or reflective coatings provided. The absorption of the projection radiation may lead to heating of the optical elements, as a result of which surface deformations may be induced in the optical elements and, in the case of refractive elements, changes in the refractive index, both directly and indirectly through thermally induced mechanical stresses. Changes in the refractive index and surface deformations in turn lead to changes in the imaging properties of the individual optical elements and also to changes in the entire projection lens. This problem area is usually dealt with under the heading "lens heating".

[0011] The lighting system may also experience degraded performance due to the light being propagated outside the illumination beam path.

[0012] In order to increase the customer's advantage in high-performance microlithography optics, the throughput of projection exposure equipment has been increased within the scope of the lithography roadmap using deep ultraviolet (DUV) radiation. Due to the higher light intensity required in this case, the increase in throughput is expected to lead to an increase in the "lens heating" effect. However, a significant increase in lens heating effects is difficult to accept when the lithography requirements remain the same or even become more stringent.

[0013] Therefore, even in the case of increased light intensity, measures seem to be needed that can help to avoid the negative effects of the "lens heating" effect where possible or limit it to a level that does not cause any effects. Summary of the invention

[0014] To solve this problem, the invention provides an optical element having the features of claim 1. Also provided is an assembly having the features of claim 9 and an optical system having at least one such optical element. Advantageous developments are specified in the dependent claims. The terms of all claims are incorporated into the description by reference.

[0015] According to a first aspect, the invention provides an optical element for incorporation into a holding device, wherein the optical element in the joined state together with the holding device forms an assembly. The assembly is used to form an optical system for a microlithography projection exposure device, in particular a projection lens or another imaging system. This optical system usually comprises a plurality of assemblies with optical elements held by them, which together define a used beam path in the assembled state, which in the case of an imaging system is also referred to as an imaging beam path.

[0016] The optical element has a transparent body, which is made of a material having high transmittance or being transparent to light of a used wavelength range. For example, the material may be synthetic fused silica or a fluoride crystal material, such as calcium fluoride. Light passage surfaces, i.e., a first light passage surface and a second light passage surface opposite thereto, are formed on opposite sides of the transparent body. If light passes through the optical element, one of the light passage surfaces serves as a light incident surface, and the other serves as a light exit surface.

[0017] For example, the optical element may be a lens element having positive or negative refractive power, or a plane parallel plate having almost no refractive power.

[0018] Each of the light channel surfaces has an optical use area and an edge area located outside the optical use area. In the combined state, the optical use area is arranged in the use beam path of the optical system. The edge area is arranged as a bonding area for a holding element of a holding device. In the combined state, it can be bonded to the edge area in the contact area. The optical use area can be used without being damaged by the holding element of the holding device. Each of the light channel surfaces is prepared to optical quality in the optical use area, which means in particular that there is practically no surface roughness that interferes with the light channel. The surface shape in the optical use area is designed according to a specified use area specification, which is derived from the desired optical effect or function of the optical element in the beam path used and is therefore specified by the so-called optical design.

[0019] Usually, if the surface shape of the optically used area continues beyond the area boundary between the optically used area and the edge area, no particularly strict requirements are imposed on the surface quality. Sometimes, due to the overshoot of the polishing tool, a part of the edge area close to the used area may still achieve more or less optical quality, but the quality will decrease as the distance from the area boundary between the used area and the edge area increases.

[0020] In the case of an optical element according to this aspect of the invention, a light deflecting structure(s) having a geometrically defined surface design, designed according to an edge region specification deviating from the use region specification, is formed in an edge region of at least one light passage facet. The light deflecting structure or its surface design is configured to deflect into a target region outside the used beam path, and the portion of light deflected or rerouted by the light deflecting structure can be specified by the edge region specification.

[0021] This aspect is partly based on the finding that part of the light on the light passage surface which propagates outside the beam path used during operation of the optical system and which may be incident on the edge region is substantially not incident from an arbitrary or randomly occurring direction of incidence. Instead, due to the structure of the optical system, the direction of incidence of most of the stray light and the position at which the stray light can be incident on the edge region can be calculated. For example, for the part of the stray light, at least for some directions of incidence of the radiation, this predictability is due to the fact that even with highly effective antireflection coatings, the residual reflectivity is sufficient to reflect a part of the incident light, precisely in a predictable exit direction.

[0022] The inventors have recognized that by means of a defined structuring of the edge region, additional benefits for the operation of the optical system can be achieved. That is, if a light deflecting structure with a geometrically defined surface design is provided, which can be specified with edge region specifications, then incident stray light can be deflected completely or at least for the most part in a targeted manner by refraction and / or diffraction and / or reflection into a specifiable target region outside the used beam path.

[0023] Thus, stray light, which was previously considered a source of interference and could not be controlled, can be guided in a targeted manner by means of appropriate edge region specifications and can be utilized for the purpose of improving the performance of the optical system.

[0024] The light deflecting structure preferably comprises a refractive and / or diffractive light deflecting structure. Thus, in this case, the deflection of the light deflecting structure can be achieved by light refraction (refraction), by light diffraction (diffraction) or by a combination of diffraction and refraction. In part, such a light deflecting structure can be constructed without much cost during the production process of the optical element, for example, it can be integrally formed with the rest of the optical element. In some cases, reflective light deflecting structures can also be provided, wherein the selectivity exists even in the case of combining these structures with refractive and / or diffractive light deflecting structures or using these reflective light deflecting structures specifically as mirror (reflective) light deflecting structures.

[0025] There are different selectivities for "using" deflected stray light. One selectivity involves setting the target area so that the stray light affected by the light deflecting structure is directed to an area that is not critical for the performance of the optical system, such as being incident on an absorbing structure that absorbs the stray light and thus has no detrimental effect on the functioning of the optical system.

[0026] In the case of an assembly with a holding device and a held optical element, the holding device comprises a holding element in the region of a contact zone which is engaged in an edge region. The contact zone is a region in which there is direct or indirect mechanical contact between the holding element and the optical element. If stray light is incident in the region of the contact zone, this may lead to heating of the contact zone and thus to possible undesired lens heating effects. In the case of clamping, these situations may arise, for example, because the holding element is directly heated by the stray light and the heat generated is transferred to the material of the optical element via the contact zone. In the case of an assembly in which the holding element of the holding device is bonded to the optical element in the region of the correspondingly assigned contact zone, the adhesive material may be heated by the action of the stray light and thus may indirectly lead to a lens heating effect. An adhesive protective layer is provided in the region of the contact zone for protecting the curable adhesive from damage by light of the wavelength used, alternatively or additionally, local heating may occur in the region of the contact zone due to absorption effects in the adhesive protective layer. If the light deflection structure is designed so that the deflected part of the light is deflected into a target area outside the contact zone, the application of the present invention can avoid or significantly reduce such problems.

[0027] Directed deflection of stray light to a designated target area also enables improvements in imaging system performance to be achieved by using the component of the stray light intensity deflected into the target area in a targeted manner to heat components located there, so as to achieve thermally induced manipulation within the optical system, particularly within the imaging system.

[0028] The use of this method can be understood as follows. The distribution of the stray light in position space and in angle space and the intensity distribution of the stray light within the distribution depends in principle not only on the optical design of the optical system, but also on the type of use during production operation. For example, the stray light distribution in a projection lens of a projection exposure device depends on the mask structure of the mask (reticle) used for imaging. Alternatively or additionally, the stray light distribution also depends on the way in which the mask is illuminated, that is to say on the so-called illumination setup. Thus, a coherent illumination setup with a specifiable Sigma value (axial illumination) leads to a stray light distribution that differs significantly from off-axis illumination, such as a dipole illumination setup, in which, for example, the mask is illuminated primarily from two directions that are obliquely opposite to each other.

[0029] More importantly, the stray light distribution and the used light distribution are influenced by the shape and position of the (effective) image field. The used light distribution can have a rectangular shape or an arcuate curved shape ("annular field"). The image field can be centered with respect to the optical axis ("axial field") or can be located outside the optical axis and off-center ("off-axis field").

[0030] The spatial distribution of the stray light intensity in the optical system can be calculated for typical combinations of mask structures and illumination settings. Now, the light deflecting structure can deflect the stray light and thus construct the thermally actuated manipulator so that the thermally actuated manipulator is designed so that its effect counteracts the adverse effects of lens heating in the region of the used beam path and is therefore able to at least partially compensate for these.

[0031] This thermally actuated manipulator is passive, meaning it has no dedicated drive or actuator. It is “controlled” by the targeted deflection of stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Additional advantages and aspects of the present invention will become apparent from the claims and the description of exemplary embodiments of the present invention, which will be explained below with reference to the accompanying drawings.

[0033] Figure 1 An exemplary embodiment of a microlithography projection exposure apparatus is shown;

[0034] Figure 2 A schematic lens element cross-section of an embodiment of a catadioptric projection lens is shown with a footprint next to it for illustrating the beam paths used;

[0035] Figure 3A and Figure 3B exist Figure 3A The figure shows the area directly behind the object plane OS. Figure 2 The magnified part of the projection lens and Figure 3B , showing an enlarged detail in the region of the contact zone between the retaining element and the lens element;

[0036] Figure 4A and 4B An exemplary embodiment is shown in which the deflection of the superaperture light is achieved by means of diffraction by means of a diffractive light deflecting structure in the edge region of the lens element;

[0037] Figure 5A and Figure 5B Meridional cross-sectional view (5A) and plan view (5B) of the top side of a lens element showing an exemplary embodiment with an azimuthal structured diffractive structure in the edge region;

[0038] Fig. 6A and Figure 6B Meridian cross-sectional view (6A) and plan view (6B) of the top side of a lens element showing an exemplary embodiment, with a refractive light deflecting structure in the edge region, which refracts in the radial direction and is in the form of a separately manufactured prism;

[0039] Fig. 7A and 7BMeridian cross-section (7A) and plan view (7B) of the top side of a lens element showing an exemplary embodiment, wherein in the edge region there is a refractive light deflecting structure which refracts in the circumferential direction and is in the form of a separately manufactured prism;

[0040] Fig. 8A and 8B An example of a thermal manipulator is shown, which operates with the aid of stray light that has been deflected in a targeted manner; and

[0041] Fig. 9 An exemplary embodiment with reflective light deflecting structures on lens element surfaces that are tilted toward the edge is shown. DETAILED DESCRIPTION

[0042] Figure 1 An example of a microlithography projection exposure device WSC is shown, which can be used for producing semiconductor components and other fine structure components and operates with light or electromagnetic radiation in the deep ultraviolet (DUV) range to obtain resolutions down to a fraction of a micrometer. An ArF excimer laser with an operating wavelength λ of about 193 nm is used as the main radiation source or light source LS. Other UV laser light sources, such as an F2 laser with an operating wavelength of 157 nm or an ArF excimer laser with an operating wavelength of 248 nm are also possible.

[0043] At its exit face ES, the illumination system ILL arranged downstream of the light source LS generates a large, sharply defined and substantially uniformly illuminated illumination field which is adapted to the telecentricity requirements of the projection lens PO located downstream in the beam path. The illumination system ILL has means for setting different illumination modes (illumination settings) and can, for example, switch between conventional axial illumination and off-axis illumination with different coherences σ. Off-axis illumination modes comprise, for example, annular illumination or dipole illumination or quadrupole illumination or any other multipole illumination. The design of suitable illumination systems is known per se and is therefore not explained in detail herein. Patent application US 2007 / 0165202 A1 (corresponding to WO 2005 / 026843 A2) shows an example of an illumination system which can be used within the scope of various embodiments.

[0044] Those optical components which receive the light from the laser LS and form illumination radiation from this light, which is guided to the reticle M, are part of an illumination system ILL of the projection exposure apparatus.

[0045] Arranged downstream of the illumination system are means RS for holding and manipulating the mask M (reticle) so that the pattern arranged at the reticle is located in the object plane OS of the projection lens PO, which coincides with the exit plane ES of the illumination system and is also referred to herein as the reticle plane OS. For the purpose of a scanning operation, the mask can be moved in this plane in a scanning direction (y direction) perpendicular to the optical axis OA (z direction) by means of a scanner drive.

[0046] Downstream of the mask plane OS is followed by the projection lens PO, which acts as a reduction lens and images the image of the pattern arranged at the mask M at a reduced scale, for example at a scale of 1:4 (|β|=0.25) or 1:5 (|β|=0.20), onto a substrate W coated with a photoresist layer, whose photosensitive substrate surface SS is located in the region of the image plane IS of the projection lens PO.

[0047] The substrate to be exposed (in the exemplary case a semiconductor wafer W) is held by means WS containing a scanner drive to move the wafer in a scanning direction perpendicular to the optical axis OA (y-direction) synchronously with the mask M. The means WS (also called "wafer stage") and the means RS (also called "reticle stage") are components of a scanning device controlled by a scanning control device, which in the present embodiment is integrated in a central control device CU of the projection exposure device.

[0048] The illumination field generated by the illumination system ILL defines the effective object field OF used during the projection exposure. In the exemplary case, the effective object field OF is a rectangle having a height A* measured parallel to the scanning direction (y-direction) and having a width B* measured perpendicular to the scanning direction (along the x-direction), B* being larger than A*. In general, the aspect ratio AR=B* / A* is between 2 and 10, in particular between 3 and 8. The effective object field is located at a distance close to the optical axis in the y-direction (off-axis field). The effective image field IF in the image plane IS is optically conjugate to the effective object field, having the same shape and the same aspect ratio between height B and width A as the effective object field, but the absolute field size is reduced by the imaging ratio β of the projection lens, i.e. A=|β|A* and B=|β|B*.

[0049] If the projection lens is designed and operated as an immersion lens, the radiation is transmitted during operation of the projection lens through a thin layer of immersion liquid, which is located between the exit face of the projection lens and the image plane IS. During immersion operation, the image side numerical aperture NA may be greater than 1. A dry lens construction is also possible; in this case, the image side numerical aperture NA is limited to less than 1.

[0050] Figure 2Schematic lens element meridian cross-section of an embodiment of a catadioptric projection lens PO with a selected beam is shown for illustrating the imaging beam path of the projection radiation passing through the projection lens during operation. The projection lens is arranged as an imaging system with a reduction effect for imaging at a reduced scale, for example in the case of a scale of 4:1, a mask pattern arranged in its object plane OS onto its image plane IS, which is aligned parallel to the object plane. Here, exactly two actual intermediate images IMI1, IMI2 are generated between the object plane and the image plane. A first lens part OP1, which consists only of transparent optical elements and is therefore refractive (refractive), is designed to image the pattern of the object plane into a first intermediate image IMI1 without substantially any change in size. A second catadioptric lens part OP2 images the first intermediate image IMI1 onto a second intermediate image IMI2 without substantially any change in size. A third refractive lens part OP3 is designed to image the second intermediate image IMI2 into the image plane IS in a sharply reduced manner.

[0051] The pupil planes or pupil surfaces P1, P2, P3 of the imaging system are located between the object plane and the first intermediate image, between the first and second intermediate images, and between the second intermediate image and the image plane, respectively, where the chief ray CR of the optical imaging intersects the optical axis OA. An aperture stop AS of the system may be attached in the region of the pupil surface P3 of the third lens part OP3. The pupil surface P2 in the catadioptric second lens part OP2 is adjacent to the concave reflector CM.

[0052] The catadioptric second lens part OP2 comprises the only concave mirror CM of the projection lens. A negative group NG with two negative lens elements is located directly upstream of the concave mirror. In this configuration, which is sometimes called Schupmann achromat, i.e. Petzval correction, that is, the correction of the field curvature is due to the curvature of the concave mirror and the negative lens element in its vicinity, and the chromatic correction is due to the refractive power of the negative lens element upstream of the concave mirror and the position of the aperture relative to the concave mirror.

[0053] The function of the reflective deflection device is to separate the beam that is transferred from the object plane OS to the concave reflector CM, or the corresponding partial beam path, from the beam or the partial beam path that passes between the concave reflector and the image plane IS after reflection at the concave reflector. To this end, the deflection device has: a planar first deflection reflector FM1, which has a first reflector surface MS1 for reflecting radiation from the object plane to the concave reflector CM; and a planar second deflection reflector FM2, which is aligned at right angles to the first deflection reflector FM1 and has a second reflector surface MS2, wherein the second deflection reflector deflects the radiation reflected from the concave reflector in the direction of the image plane IS. Since the optical axis is folded at the deflection reflector, the deflection reflector is also called a folding reflector in the present application. The deflection reflector is tilted relative to the optical axis OA of the projection lens about a tilt axis extending perpendicular to the optical axis and parallel to the first direction (x direction), for example 45°. When the projection lens is configured for scanning operation, the first direction (x direction) is perpendicular to the scanning direction (y direction) and thus perpendicular to the direction of movement of the mask (reticle) and the substrate (wafer). For this purpose, the deflection device is implemented as a prism, the inner reflection surfaces (cathetus surfaces) of which are externally reflectively coated are arranged perpendicular to each other to act as deflection mirrors.

[0054] The intermediate images IMI1, IMI2 are located closest to their optically adjacent folding mirrors FM1 and FM2, respectively, but maintain a minimum optical distance from them so that any defects on the mirror surfaces are not clearly imaged into the image plane, and the plane deflection mirrors (plane mirrors) FM1, FM2 are located in a region of medium radiation energy density.

[0055] The position of the (paraxial) intermediate image defines a field plane of the system, which is optically conjugate to the object plane and the image plane, respectively. The deflecting mirrors are therefore optically close to the field planes of the system, also referred to as "near field" in the context of the present invention. In this case, the first deflecting mirror is configured to be optically close to a first field plane belonging to the first intermediate image IMI1, and the second deflecting mirror is configured to be optically close to a second field plane, which is optically conjugate to the first field plane and belongs to the second intermediate image IMI2.

[0056] In the present invention, the optical proximity or optical distance of an optical surface relative to a reference plane (e.g., a field plane or a pupil plane) is described by the so-called subaperture ratio SAR. For the purposes of the present invention, the subaperture ratio SAR of an optical surface is defined as follows:

[0057] SAR=sign h(|r| / (|h|+|r|))

[0058] where r denotes the marginal ray height, h denotes the chief ray height, the sign function sign x denotes the sign of x, by convention sign 0 = 1. The chief ray height is understood to be the ray height of the principal ray of the field point of the object field which has the maximum field height in terms of amplitude. The ray heights should be understood to be signed. The marginal ray height is understood to be the ray height of the ray with the largest aperture starting from the intersection point between the optical axis and the object plane. This field point does not necessarily contribute to the transfer of the pattern configured in the object plane - in particular in the case of off-axis image fields.

[0059] The subaperture ratio is a signed variable that is a measure of the proximity of the field or pupil to a plane in the beam path. By definition, the subaperture ratio is normalized to a value between -1 and +1, where the subaperture ratio is zero in each field plane and where the subaperture ratio in the pupil plane jumps from -1 to +1, or vice versa. Thus, the pupil plane is determined by a subaperture ratio of 1 in absolute value.

[0060] An optical surface or plane is designated as being "(optically) close" to an optical reference surface if the subaperture ratios of the optical surfaces or planes are comparable in value.

[0061] Specifically, an optical surface or plane is designated as "(optically) near field" if its subaperture ratio is close to 0. An optical surface or plane is designated as "(optically) near pupil" if its absolute value of subaperture ratio is close to 1.

[0062] The used beam path of the projection lens, also called the imaging beam path or the projection beam path, extends from the effective object field OF to the effective image field IF. The used beam path is a volume in three-dimensional space (“R 3 A subset of the image beam path is defined as a point in space through which at least one continuous ray passes from the object field OF within the aperture used on the object side to the image field IF within the aperture used on the image side. The shape and position of the imaging beam path during the process usually depends on the current field size and diffraction order.

[0063] The area of ​​the optical surface illuminated by the radiation from the projection beam path of the effective object field OF is also referred to in this application as the "footprint". Here, the footprint of the projection radiation on the optical surface denotes the size and shape of the intersection between the projection beam and the surface illuminated by the projection beam. Next to the lens element part, Figure 2The footprint FP at different positions along the projection beam path is schematically shown. With the help of the footprint of the effective object field OF, which is essentially rectangular in form, the optical vicinity of the nearest field plane can be identified, with the edge region being slightly rounded (see, for example, near the lens element L1-1 or on the deflection mirror near the intermediate image). The footprint is located outside the optical axis OA, just like the object field. In contrast, illuminating an essentially circular area in the region of a pupil plane, which is Fourier transformed with respect to the field plane, results in a footprint in the pupil region that is at least approximately circular in shape (see P1 in the refractive first lens part OP1 or P2 in the optical vicinity of the concave mirror CM). The footprint can provide information in particular on the spatial distribution of the radiation-induced heating.

[0064] During operation, there are usually rays which are not part of the used beam path. These include in particular the so-called "superaperture rays". In the present context, it is understood that these are those rays which are endowed with diffraction by the structured mask and which are emitted at an object-side aperture angle greater than the object-side aperture angle used for imaging, which is determined by the current diameter of the aperture stop which defines the projection beam path. This object-side aperture angle defines the object-side aperture used. A corresponding statement also applies to the image side, i.e. the side on which the image is optically conjugate to the object.

[0065] To further explain some of the problems and their solutions that form the basis of the present invention, Figure 3A Shows the area immediately behind the object plane OS. Figure 2 Magnified portion of a projection lens, wherein during operation a mask M of a structure PAT to be imaged is located in the object plane. Shown is a plane-parallel plate PP (optical element without refractive power) following the object plane and a lens element L1-1, which follows the plane-parallel plate and is the first transparent optical element closest to the object and having refractive power as part of the projection lens. In general, the reference numeral OE shall denote an optical element.

[0066] The body K of the lens element L1-1 is transparent under ultraviolet light (for example, made of synthetic fused quartz), and the lens element L1-1 is formed as a relatively thick biconvex lens element having a first light channel surface LF1 (light incident surface LF1) facing the object plane and an opposite second light channel surface (LF2) (light exit surface LF2).

[0067] Under all conditions of use, the lens element must perform its designated optical function in the beam path as best as possible. Therefore, each of the light channel surfaces LF1, LF2 has an optical use area NB1, NB2, which includes the optical axis area and extends radially outward therefrom, so that under all operating conditions, all rays of the projection beam path pass through the optical use area on the incident side and the exit side. Ray ST1 propagating at the edge of the projection beam is shown. Each lens element surface has an edge area RB1, RB2 radially outside the optical use area, and the edge area RB1, RB2 surrounds the corresponding optical use area in a ring shape.

[0068] In the combined state, the optical element or lens element L1-1 is carried by a holding device or mounting seat, which comprises several holding elements HE distributed over the circumference of the lens element and on which the lens element rests in the case of a vertical orientation of the projection lens. The mounting or holding device, and the lens element mounted or held therein, together form a subassembly BG which, together with other subassemblies containing other optical elements, forms the projection lens.

[0069] The contact areas KZO between the holding element and the exit-side light channel surface LF2 are located in the edge area of ​​the lens element in an azimuthally distributed manner and each contacts the lens element in the area of ​​the contact area KZO. Figure 3B The enlarged detail of the area of ​​the middle contact zone KZO clearly shows that the light exit side LF2 of the lens element is bonded to the holding element HE. The area of ​​the bonded connection has a multilayer structure. An adhesive layer KL consisting of an adhesive material is applied to the support surface of the holding element. Before the adhesive connection is established in the area of ​​the contact zone, an adhesive protection layer KSS arranged between the adhesive layer and the light exit surface LF2 is applied to the edge area of ​​the light exit side LF2. The UV radiation-absorbing adhesive protection layer protects the adjacent adhesive layer KL from UV radiation (UV radiation can pass through the lens element in the edge area to the adhesive layer) and thus increases the service life of the adhesive connection.

[0070] Each of the light passage surfaces is prepared in an optical use area NB1, NB2 to optical quality and has a surface shape designed according to the use area specification. The use area specification is then specified by the function of the optical element in the beam path used. The use area specification is defined within the scope of the computational optical design. In the exemplary case, both lens element surfaces LF1, LF2 are spherically curved in the use area.

[0071] In contrast, it is expected that the edge regions RB1, RB2 will not participate in the imaging. Although in the case of conventional lens elements the surface shape in the edge region still corresponds to the mathematical continuation of the surface shape in the use region, at least in the region of the radial distance to the transition between the use region and the edge region (dashed line), the optical surface is significantly rougher and in this respect of poorer optical quality, since these surface portions are not required for imaging.

[0072] The properties of the optical element L1 - 1 relate to its influence on radiation which travels outside the projection beam path and strikes an edge region radially outside the optically used area. Figure 3A The so-called super-aperture ray UAP is shown, in which the mask M of a specified structure deflects the light propagating therein and emits it at a larger object-side aperture angle than that used for imaging. The object-side aperture angle is specified by the diameter of the aperture stop.

[0073] The solid line in FIG3 shows the path of the superaperture ray UAP, which passes through the light channel surface LF1 into the lens element material in the incident side edge region RB1, passes through the lens element material and through the light channel surface LF2 on the light exit side to reach the area of ​​the contact zone KZO. The adhesive protection layer KSS absorbs the radiation energy, which can heat the adjacent lens elements and adjacent holding elements, and can selectively heat the adjacent areas of the mounting. Due to the locally generated heat, an unwanted lens heating effect may occur.

[0074] In the illustrated embodiment, this problem is avoided because the edge area of ​​the incident-side light channel surface LF1 is not a simple extrapolation of the surface shape of the light incident side in the used area, but is given a geometrically defined surface design in the process, and the edge area is designed according to the edge area specification that deviates from the used area specification. In the exemplary case, the specific shape of the light incident surface in the edge area RB1 on the light incident side is selected so that the incident-side edge area RB1 has a rotationally symmetric aspherical shape. The rotationally symmetric aspherical shape appears smoothly or continuously from the surface shape of the used area in the transition area between the used area and the edge area, that is, there is no edge or jump, but in the edge area it clearly deviates from the mathematical continuation of the used area, which is depicted by the dotted line.

[0075] In an exemplary case, the incident-side light channel surface LF1 is convexly spherically curved in the optically used area, and as the distance from the optical axis increases, the convex curvature in the edge area after the inflection point becomes a narrow area with a concave curvature, and then a convex curvature appears again at a farther distance. This establishes a refractive light deflection structure LUS1, which ensures that the super-aperture light UAP deflected by diffraction can reach a target area ZB outside the beam path used, which target area can be specified by the edge area specification. In the current case, the target area is defined so that it is located (radially) outside the contact zone KZO. In other words: the contact zone is protected from the influence of the super-aperture rays by the refractive light deflection structure LUS1, because the super-aperture rays are deflected through the outer contact zone and enter the non-critical area outside the contact zone, which is illustrated by the broken super-aperture rays UAP' drawn with a dotted line.

[0076] The target area ZB into which the deflected superaperture light bypassing the contact zone is incident should be sufficiently large or have a considerable mass so that it will only experience a relatively small temperature change in the event of radiation incidence. Furthermore, this area should have a good thermal connection to the outside so that heat does not flow back into the lens element via the holding element.

[0077] From a manufacturing perspective, it is relatively easy to achieve a targeted deflection of superaperture light by means of an aspheric surface in the edge region of the light incident side of the lens element, since the rotationally symmetric aspheric surface (light deflecting structure LUS1) can be manufactured together with the rotationally symmetric design in the optically used area in a single working step.

[0078] exist Figure 3A In the example of the embodiment of the invention, the light deflecting structure LUS1 has a continuously curved surface shape in the entire edge region, which surface shape has a negative radius of curvature in at least one region, wherein the center of curvature is therefore located on the light incident side. This results in a diverging function, or an annular circumferentially diverging lens element, or a diverging zone.

[0079] An alternative to designing a refractive light deflecting structure for the purpose of deflecting superaperture light can be achieved by means of a light deflecting structure having a Fresnel lens ring in the edge region. Thus, the aspherical surface in the edge region can be embodied as an annular Fresnel lens element, whereby, compared to Figure 3A The larger aspheric surface in the lens can save installation space.

[0080] In the exemplary embodiments explained below, for the sake of clarity, a portion of Figure 3A The same reference numerals are used for the same or similar features. Regarding the configuration and basic shape of the lens element L1-1, please refer to the above examples.

[0081] Figure 4A and 4BAn exemplary embodiment is shown in which the deflection of the superaperture light is achieved by means of diffraction by means of a light deflection structure LUS2 in the form of a diffractive structure in the edge region of the lens element. Figure 4A Shown with Figure 3A Similar meridian profile, and Figure 4B The top side of the lens element facing the object plane (first light passage face LF1) is shown in plan view. The diffractive light deflecting structure LUS2 is formed by a diffraction grating having a circular diffractive structure and formed rotationally symmetrically with respect to the optical axis, resulting in a diffraction of the incident radiation mainly outwards in the radial direction in each case. In the exemplary case, the light deflecting structure LUS2 has a blazed grating which has a diffractive effect on light of the used wavelength. Figure 4A As can be clearly seen in the figure, it has a cross-sectional ring designed in a sawtooth shape. Its radial spacing and the angles of the sawtooth surfaces are matched to one another so that for a certain diffraction order, the diffraction efficiency is maximum at the wavelength used. As a result, most of the intensity components of the narrowband projection radiation are concentrated in the single required diffraction order, with hardly any intensity remaining in the other orders, in particular in the zero diffraction order, that is to say during the direct passage through the diffraction grating. In this way, the desired deflection angle can be set very accurately and the light intensity of the deflected superaperture ray UAP' is concentrated only in a narrow target area ZB, which is particularly advantageous in complex installation situations. Here, the light deflection structure is also designed so that the deflected stray light is rerouted and no stray light hits the contact zone KZO. Within the scope of the production of the lens element, the rotationally symmetrical blazed grating and the lens element can be produced simultaneously and from the same material.

[0082] For manufacturing reasons, it may be advantageous to create a light deflecting structure that is rotationally symmetric with respect to the optical axis of the optical element, but in many cases this becomes unnecessary or may be undesirable for functional reasons. There are therefore exemplary embodiments in which the optically effective surface shape of the edge region is not rotationally symmetric with respect to the optical axis. In particular, the surface shape may have an n-fold rotational symmetry with respect to the optical axis in the edge region, where n may be, for example, 2, 3, 4, 6 or 8. Several examples are explained below.

[0083] Figure 5A and 5B Meridian cross-sectional view (5A) and plan view (5B) of the top side of the lens element of an exemplary embodiment are shown. Figure 5B ). The deflection of the super-aperture light is achieved by using the azimuthally structured diffraction structure in the entrance side edge region RB1 of the lens element. Figure 5A It can be clearly seen that the light deflecting structure LUS3 is designed as a diffraction structure, that is, as a diffraction grating, more precisely in the form of a blazed grating. Figure 4A , 4BUnlike the variant in , eight essentially rectangular grating regions GB are provided in a locally limited manner within the annular edge region RB1 only in those angular regions that are each circumferentially offset by 45°, below which a contact region or a retaining element is provided approximately in the center. Again, the diffraction grating lines are curved in the circumferential direction with a uniform radius of curvature, but are not continuous in the circumferential direction, but only in a narrow angular range, for example, between an angular width of 10° and 30°.

[0084] The diffractive structure with a sawtooth cross section can be integrally formed with the material of the lens element body and can be manufactured together with the lens element body. However, in an exemplary case, a different process is selected by forming a light deflection structure LUS3 on a separate optical light deflection element LUE, which is manufactured separately from the transparent body of the optical element and is attached only to a specified area within the incident side edge region RB1 at the optical element body after completion. Here, each light deflection element LUE has a contact surface on the side opposite to the light deflection structure, and the design of the contact surface matches the surface shape of the lens element body in the edge region so that it can be firmly attached, for example directly by optical contact bonding without auxiliary devices or with the help of a thin adhesive layer or optical adhesive. In this way, even relatively complex distributions of light deflection characteristics in the edge region can be achieved within the scope of a relatively well-controlled process. Optionally, it is also possible to process planes into the edge region at the positions provided for the light deflection elements, because these are particularly suitable for contacting the planes where the light deflection elements are located without auxiliary devices by means of optical contact bonding.

[0085] based on Fig. 6A and 6B A variant is explained in which a refractive light deflecting structure in the form of a prism PR in the edge region of a lens element is used to deflect the superaperture light. The presentation is the same as in the previous example. Figure 6B The plan view of the top side of the lens element in FIG. 1 shows a total of eight light deflection elements LUE in the form of prisms, which are distributed on the circumference at the same 45° angle and attached to the edge region RB1, wherein each bonding location is assigned a prism. Fig. 6A It can be clearly seen from the meridian cross-section of that the inclined prism surface with the normal direction PN points inward in the radial direction, so that the incident super-aperture light is deflected outward in the radial direction. Similar to the example of FIG5 , the refractive light deflecting structure designed as a prism is manufactured in the form of a separate light deflecting element LUE, which is placed in an appropriate position in the edge region and optically neutrally connected to the lens element body after the lens element surface is completed, for example by means of optical contact bonding or optical adhesive.

[0086] Fig. 7A and 7BFor explaining another embodiment, the light deflecting structure LUS5 is in the form of a prism PR, which is initially manufactured separately from the lens element body as a separate prism element and then attached to the lens element at a suitable position in the entrance side edge region RB1 by optical contact bonding or optical adhesive. Fig. 6A , 6B In a variant of FIG. 5 , the prism surface PF in the beam path at an inclined angle for light deflection purposes is directed toward its surface normal PN and not in the radial direction but in the circumferential direction (azimuthal direction). Fig. 7A It can be clearly seen that this causes the super-aperture light energy to be deflected so that no super-aperture light in this region is incident on the contact zone KZO of the holding element.

[0087] The diffraction structure can also be used to deflect light in the circumferential direction. Figure 5A , 5B The light deflection element in the projection lens is designed so that the grating lines of the diffractive structure are essentially aligned in the radial direction. As a result, a relatively large degree of freedom with respect to the deflection angle and the direction of the stray light deflection can be achieved. In other words, the target area can be located at significantly different positions in the projection lens.

[0088] In the previous embodiments, the light deflection structure is primarily designed to prevent superaperture light and other stray light from being incident on the light exit surface in certain areas, specifically, for example, anywhere where the holding element is provided in the area of ​​the contact zone and optionally wherever the absorption layer is present. The connection point between the holding element and the lens element is thus protected from heating effects caused by stray light.

[0089] However, the performance of the projection lens can also be improved by means of a targeted deflection of stray light onto a defined target area, whereby certain components of the stray light intensity or the entire stray light intensity is deflected onto a target area or multiple target areas, so that component parts placed there can be heated in a targeted manner and thus independently achieve desired and predictable thermally induced manipulation within the optical system.

[0090] based on Fig. 8A and 8B An example of thermal manipulation by means of stray light deflected in a targeted manner is explained. Specifically, a thermal manipulator is established which independently causes a certain homogenization or equalization of the temperature distribution within an optical element OE, such as a lens element, during operation. Fig. 8A and 8B Both show an axial plan view of a transparent optical element OE which is optically arranged near the field plane of a projection lens with off-axis object field and image field (off-axis system). For example, the optical element may be Figure 2The optical element is mounted in a holding device comprising eight holding elements HE1, HE2, etc., which are evenly distributed around the circumference of the optical element and on which an edge region RB of the optical element is arranged. The transparent optical element is firmly connected to the holding elements by means of an adhesive layer protected by an adhesive protective layer.

[0091] Due to the shown near-field configuration of the light entry surface (first light passage surface LF1), the light propagating along the projection beam path generates an illumination footprint FP on the lens element surface, which has a substantially rectangular effective object field, with at least slightly rounded corners taking into account the distance to the field plane. In the case of asymmetric illumination with respect to the optical axis OA, the traversing projection light generates a non-rotationally symmetric, asymmetric temperature distribution within the optical element OA. If the temperature distribution in the edge region RB is taken into account, relatively warm zones WZ are generated in the corners of the illumination field close to the edge of the optical element.

[0092] Stray light propagating outside the imaging beam path is incident on the lens element in approximately the same manner over the entire edge region. The contact areas of the holding elements HE1 and HE3 to HE7 are not protected, so that the super-aperture light can slightly heat the contact areas located thereon. In contrast, the contact areas of the holding elements HE2 (in the two o'clock direction) and HE8 (in the ten o'clock direction) are protected from the impact of the incident stray light by the light deflection structure LUS6 formed on the light entrance side, and thus are kept at a relatively cool temperature compared to the contact areas of the other holding elements exposed to the stray light. Due to the uneven thermal distribution of the heat generated by the stray light in the circumferential direction, the asymmetric thermal distribution occurring in the area of ​​the cover area FP can be at least partially compensated, so that the temperature distribution within the optical element OE is more uniform or more homogeneous than in the case without the light deflection structure LUS5.

[0093] In the example, a diffractive light deflecting structure LUS6 is used which deflects stray light radially outwards. A similar effect can also be achieved using a refractive light deflecting structure and / or using a light deflecting structure which deflects light in a circumferential direction.

[0094] Figure 8B Show Fig. 8A Variations of the configuration in which different homogenization of the temperature distribution can be achieved. Fig. 8A In the example of FIG. 1 , the adhesive protective layer KSS covers all the holding elements HE3 to HE7 and the area inserted in the circumferential direction. Figure 8BIn the example of FIG. 1 , the adhesive protection layer KSS is circumferential in the circumferential direction and is attached to the light exit side in the edge region RB, between the light exit side and the holding element arranged there. If superaperture light is incident on this region, the edge region is locally heated over the covered angular range (slightly greater than 180°) due to the absorption of stray light in the adhesive protection layer. In combination with the light deflecting structure LUS6 in the region of the holding elements HE2 and HE8 closest to the covered area, this can lead to an even better degree of homogenization of the temperature distribution within the optical element.

[0095] The inventive concept is not limited to the use of refractive and / or diffractive light deflecting structures. It is also possible and advantageous in certain cases to use light deflecting structures operating according to the reflection principle. Fig. 9 An example is schematically shown. The lens element L1-1M has an exit-side light passage surface LF2, whose surface shape corresponds to the corresponding light exit surface in FIG. 3. In the use area NB1, the incident-side light passage surface LF1 also has the same surface shape. This deviation is found in the edge area RB1 on the light incident side. Although the edge area specification is selected in the exemplary embodiment of FIG. 3 so that the light passage surface is curved upward in the radial direction, that is, toward the light incident side, in the Fig. 9 In the variant of , the opposite is true. In this case, the edge region specification is such that the curvature of the edge region in the radial direction is significantly greater than the curvature in the case of an imaginary extension V of the surface shape from the used area. In other words, an entrance surface with a convex curvature is present in the used area, and the adjoining edge region RB1 also has a convex curvature, although its radius of curvature is smaller. The annular edge region RB1 is therefore designed to be inclined radially outwards.

[0096] A single or multi-layer reflective coating (mirror coating) REF is applied over the entire surface within the edge region RB1. If the super-aperture light UAP is incident on the reflective edge region, its propagation direction will be opposite to the normal light propagation direction, and it will be reflected radially outward and backward into the target region ZB, which is located upstream of the lens element, that is, between the lens element and the object plane, as viewed along the optical axis. An absorber or any other light capturing structure is provided in the target region. In this way, the contact area in the area of ​​the holding element can also be protected from the irradiation of the super-aperture light. In this variant, the specific specification of the surface shape in the edge region is also achieved by the edge region specification, which ensures that the surface design of the mirror surface can be accurately calculated to accurately deflect the super-aperture light from a known range of incident angles to the desired target region ZB.

[0097] Aspects of the invention have been described above using the example of an optical imaging system in the form of a microlithography projection lens. The invention can also be used in other optical systems, such as an illumination system for constituting a microlithography projection exposure apparatus. Problems due to superaperture light can also occur in illumination systems, such as damage to the adhesive due to radiation load plus the lack of an adhesive protection layer.

Claims

1. An optical element (L1-1, OE) which is incorporated into a holding device to form a component (BG) of an optical system (PO) for forming a microlithographic projection exposure apparatus, wherein The optical element comprises a main body (K) which is transparent to light in a used wavelength range and on which a first light passage surface (LF1) and an opposite second light passage surface (LF2) are formed; and Each of the light passage surfaces (LF1, LF2) has: an optical use area (NB1, NB2) which is arranged for being arranged in a use beam path of the optical system; and an edge area (RB1, RB2) which is located outside the optical use area and is designated as a bonding area for a holding element (HE) of the holding device, in, Each optical path facet is prepared to optical quality in the optical use area (NB1, NB2) and has a surface shape designed according to the use area specification specified by the function of the optical element (L1-1, OE) in the use beam path, Features A light deflection structure (LUS1, LUS2, LUS3, LUS4, LUS5, LUS6) ​​having a geometrically defined surface design is formed in an edge region (RB1) of at least one of the light channel surfaces (LF1), the surface design being designed according to an edge region specification deviating from the use region specification and being configured to deflect part of the light deflected by the light deflection structure into a target region (ZB) outside the use beam path; and wherein A plurality of contact zones (KZO) distributed on the circumference of the edge region are defined in the edge region of the light channel surface, which is opposite to the light channel surface containing the light deflecting structure, And wherein, the light deflecting structures (LUS1, LUS2, LUS3, LUS4, LUS5, LUS6) ​​are configured so that part of the light deflected by the light deflecting structures can be deflected to the target area (ZB) outside the contact area.

2. The optical element according to claim 1, wherein The light deflecting structure comprises a refractive and / or diffractive light deflecting structure (LUS1, LUS2, LUS3, LUS4, LUS5), and the light deflecting structure preferably comprises a refractive light deflecting structure (LUS6) ​​instead of or in addition thereto.

3. An optical element according to any one of the preceding claims, characterized in that The light deflection structure satisfies at least one of the following conditions: (i) the edge region specification is adapted to the use region specification so that the surface shape of the use region (NB1) in the transition region outside the use region in the edge region (RB1) is smoothly transformed into the surface shape of the edge region; (ii) the light passage surface has a continuously curved aspherical shape according to the edge region specification in the edge region, and has a spherical shape or an aspherical shape according to the use region specification in the optical use region; (iii) the light deflecting structure has a continuously curved shape in the entire edge region and has a negative radius of curvature in at least one region; (iv) an inflection point region, which starts to transform from the light passage surface having a positive curvature radius on the optical use area side to the light passage surface having a negative curvature radius and is located at a certain distance from the optical use area in the edge region.

4. An optical element according to any one of the preceding claims, characterized in that The light deflecting structure includes a Fresnel lens ring and / or the light deflecting structure includes a diffraction grating (LUS2, LUS3, LUS6) ​​having a diffraction effect on light of the used wavelength and / or the light deflecting structure includes a blazed grating (LUS2, LUS3) having a diffraction effect on light of the used wavelength.

5. An optical element according to any one of the preceding claims, characterized in that The optical element (OE) has an optical axis (OA) and the surface shape of the optically used area (NB) is rotationally symmetric with respect to the optical axis, wherein the surface shape of the edge area (RB) is not rotationally symmetric with respect to the optical axis.

6. The optical element according to claim 5, wherein: The surface shape in the edge region comprises an n-fold rotational symmetry relative to the optical axis, wherein n is in particular 2, 3, 4 or 6.

7. An optical element as claimed in any one of the preceding claims, characterized in that The light deflection structure is integrally formed with the material of the optical element, and / or the light deflection structure (LUS3) is formed on a separate optical light deflection element (LUE), which is manufactured separately from the transparent body (K) of the optical element and attached to the edge area (RB) in a designated area.

8. An optical element according to any one of the preceding claims, characterized in that The light deflecting structure is designed based on a calculation of the spatial distribution of the stray light intensity in the optical system for a specified combination of mask structure and illumination settings in such a way that a thermally actuated manipulator is present and is designed such that its effect is able to counteract and at least partially compensate for the adverse effects of lens heating in the region of the used beam path.

9. A component (BG) comprising an optical element (OE) and a holding device for holding the optical element, wherein The optical element (OE) comprises a body (K) which is transparent to light of the wavelength range used and on which a first light passage face (LF1) and an opposite second light passage face (LF2) are formed; and Each of the light channel surfaces has: an optical use area (NB) located in the use beam path; and a edge area (RB) located outside the optical use area, wherein: In the optical use area, the light passage surface is prepared to optical quality according to a specification surface shape specified by the function of the optical element in the use beam path, and The holding device comprises a holding element (HE) which engages in the region of a contact zone in the edge region (RB) of the second light channel surface (LF2), Features A light deflecting structure (LUS1, LUS2, LUS3, LUS4, LUS5, LUS6) ​​with a geometrically defined surface design is formed in the edge area (RB) of the first light channel surface, and is configured to deflect part of the light deflected by the light deflecting structure to a target area (ZB) outside the contact area (KZ).

10. The assembly according to claim 9, characterized in that The surface shape of the light deflecting structure is irregular in the azimuthal direction, wherein the maximum density of the light deflecting structure is arranged near the optical use coverage area where the used beam path intersects the light channel surface.

11. The assembly according to claim 9 or 10, characterized in that A material which is highly absorbing at the wavelength used is arranged in the target zone (ZB) of the light deflecting structure, the absorption rate of which material is greater than the absorption rate of the transparent material of the optical element.

12. An optical system comprising at least one optical element according to any one of claims 1 to 8 and / or comprising at least one assembly (BG) according to any one of claims 9 to 11.

13. The optical system according to claim 12, wherein: The optical system is an optical imaging system used for forming a microlithography projection exposure device, in particular a refractive or catadioptric microlithography projection lens (PO).

Images