Connection of a holding element to an optical element by means of a connecting material

Abstract

The invention relates to a method for connecting a holding element (1) to an optical element (2) by means of a connecting material (3), comprising the steps of: arranging the connecting material (3) between the holding element (1) and the optical element (2), and curing the connecting material (3), wherein the connecting material (3) is irradiated with radiation (4) for curing the connecting material (3) for curing. The object of providing a method with which a holding element can be connected to an optical element in a process-reliable manner, which allows flexible optical designs and is cost-effective, is achieved in that the radiation (4) for curing the connecting material (3) is coupled into the connecting material (3) by means of a deflection device (5) for deflecting the radiation (4).The invention further relates to a holding element (1) for connection to an optical element (2) by means of a connecting material (3) and to a system (10) for connecting a holding element (1) to an optical element (2) by means of a connecting material (3), in particular for carrying out the method according to the invention.

Description

Technical area

[0001] The invention relates to a method for connecting a holding element to an optical element by means of a connecting material, comprising the steps of: arranging the connecting material between the holding element and the optical element, and curing the connecting material, wherein the connecting material is irradiated with radiation for curing the connecting material. Furthermore, the invention relates to a holding element for connecting to an optical element by means of a connecting material and to a system for connecting a holding element to an optical element by means of a connecting material, in particular for carrying out the method according to the invention. background

[0002] It is known from the prior art to insert lenses into mounts and bond them together using adhesives. Such optical assemblies are used, for example, in lighting systems and projection lenses for structuring and process control in microlithography. The use of adhesives that can be cured using UV light has proven particularly advantageous for achieving a permanent bond.

[0003] In the known processes, UV adhesive is applied to the designated bonding points through injection channels between the lens and the mount and irradiated with a UV light source to cure it. For this purpose, the UV light source is manually aligned to the bonding points so that they are directly irradiated by imaging the focus of the UV light source through the upper optical surface of the lens onto the edge cylinder of the lens. Different lens geometries accept different angles of incidence to introduce the light into the bonding gap. Convex optical surfaces, in particular, are particularly poorly suited for coupling light for adhesive activation, since total internal reflection of the excitation radiation is more likely on convex surfaces. The known process therefore limits the implementation of optical designs.

[0004] Combined with positional and angular deviations of the UV light source due to manual positioning, this can also result in significant fluctuations in the intensity and dose of the irradiation, which in turn impacts the reliable curing of the adhesive. This results in a risk of fluctuations in the strength of the adhesive, which can lead to positional drift of the lens. The known process therefore also entails an increased process risk.

[0005] The object of the present invention is to provide a method for connecting a holding element to an optical element by means of a connecting material, which overcomes the disadvantages of the prior art. In particular, a method is to be provided with which a holding element can be connected to an optical element in a process-reliable manner, which allows flexible optical designs and is cost-effective. A further object of the invention is to provide a holding element for connection to an optical element by means of a connecting material and a system for connecting a holding element to an optical element by means of a connecting material, in particular for carrying out the method according to the invention.

[0006] According to a first aspect of the present invention, the stated object is achieved for a method for connecting a holding element to an optical element by means of a connecting material, comprising the steps of: arranging the connecting material between the holding element and the optical element, and curing the connecting material, wherein the connecting material is irradiated with radiation for curing the connecting material for curing, in that the radiation for curing the connecting material is coupled into the connecting material by means of a deflection device for deflecting the radiation. The method is particularly suitable for the integral connection of a holding element to an optical element. With the method, a permanent connection between the holding element and the optical element can be achieved.Thus, the method serves in particular for producing an optical assembly comprising a holding element and an optical element connected to the holding element. The optical assembly is particularly suitable for use in a microlithography system, for example in an exposure and / or projection system of a microlithography system.

[0007] The holding element is suitable for connection to the optical element. The holding element can be a holding element for microlithography. The holding element can be, for example, a mount, in particular a lens mount. With the aid of the holding element, it is particularly possible to arrange the optical element in an optical system, for example a projection system of a projection exposure system for microlithography. The holding element can serve in particular to position the optical element, for example on an optical axis of the optical system. The material of the holding element comprises, for example, metal and / or ceramic.

[0008] The optical element can be an optical element for microlithography. In particular, the optical element is an at least partially transparent optical element. The optical element comprises, for example, a transparent substrate. The substrate of the optical element comprises, in particular, a material that is transparent to radiation from a spectral range suitable for curing the bonding material. The substrate of the optical element transmits, in particular, in the ultraviolet spectral range. For this purpose, the substrate of the optical element can comprise a material that is transparent to wavelengths in the ultraviolet spectral range. For example, the substrate can comprise quartz glass, calcium fluoride, magnesium fluoride, barium fluoride, strontium fluoride, germanium dioxide glass, and / or any other type of glass, for example FK5, LLF1, or LF5.The material used depends, for example, on the useful wavelength of the system, in particular the projection exposure system, in which the optical element is used. The optical element can be a lens, for example, a lens with at least one convex and / or concave optical surface. It is also conceivable that the optical element is a plane plate, a mirror, a Mangin mirror, or a transmitting diffractive optical element.

[0009] The optical element is connected to the holding element by means of a connecting material, in particular a curable connecting material. The connecting material is suitable for the integral connection of the optical element to the holding element. The connecting material is, for example, an adhesive, in particular a radiation-activatable adhesive. The adhesive can be curable by ultraviolet light, in particular ultraviolet light with a specific spectral distribution. For example, the use of an epoxy resin-based adhesive that can be cured with UV light of the Hg-I line is conceivable. It is also conceivable to use an adhesive that is cured with radiation from a different spectral range.

[0010] The bonding material is arranged between the holding element and the optical element. Arranging the bonding material between the holding element and the optical element may comprise applying the bonding material to at least one connection point between the holding element and the optical element. The bonding material may, for example, be applied to the holding element and / or to the optical element.

[0011] In order to achieve a material-to-material connection between the holding element and the optical element, the connecting material is cured. With the cured connecting material, a permanent connection between the holding element and the optical element can be achieved. For curing, the connecting material is irradiated with radiation to harden the connecting material. The radiation source can be selected depending on its compatibility with the selected connecting material. For example, it is conceivable that the connecting material is irradiated with UV radiation. The UV radiation can be provided by a UV radiation source, in particular a UV condenser. It is also conceivable that the connecting material is irradiated with radiation from a different spectral range. To cure the connecting material, the radiation is at least partially coupled into the connecting material.

[0012] The radiation for curing the bonding material is coupled into the bonding material by means of a deflection device. The deflection device is suitable for deflecting radiation for curing the bonding material. In particular, the deflection device is designed to deflect the radiation for curing the bonding material in the direction of the bonding material. For example, the deflection device can be a deflection element. With the aid of the deflection device, radiation for curing the bonding material can be deflected, for example, from a first direction into a second direction. The deflection device is designed in particular such that radiation impinging on the deflection device and / or radiation coupled into the deflection device for curing the bonding material is coupled into the bonding material between the holding element and the optical element by means of the deflection device.The deflection device can, for example, be arranged adjacent to the optical element.

[0013] It has been shown that coupling radiation into the joining material to cure it by means of a deflection device allows indirect irradiation of the joining material. Indirect irradiation can be understood as meaning that the radiation source is not directed directly at the joining material, but rather at the at least one deflection device, which then directs the radiation in the direction of the joining material. With the aid of the method, curing of the joining material can therefore be achieved without the need for direct irradiation of the joining material. This advantageously makes it possible to largely decouple the positioning of the radiation source from the design of the optical element. Rather, the invention enables uniform coupling of radiation into the joining material regardless of the geometry of the optical element.This is particularly advantageous because the geometry of the optical design can follow other higher boundary conditions, which result in particular from the desired function of the optical assembly, for example user requirements for the microlithography system.

[0014] According to a second aspect of the present invention, the stated object for a holding element for connection to an optical element by means of a connecting material is achieved in that the holding element comprises at least one deflection device for deflecting radiation for curing the connecting material, wherein the deflection device is designed such that radiation incident on the deflection device for curing the connecting material is coupled into the connecting material between the holding element and the optical element by means of the deflection device. The holding element for connection to an optical element by means of a connecting material is particularly suitable for carrying out a method according to the first aspect. The holding element is particularly suitable for use in a microlithography system, for example in an exposure and / or projection system of a microlithography system.

[0015] According to a third aspect of the present invention, the stated object is achieved for a system for connecting a holding element to an optical element by means of a connecting material, comprising: an optical element, and a holding element for connection to the optical element, in that the system comprises at least one deflection device for deflecting radiation for curing the connecting material, wherein the deflection device is designed such that radiation incident on the deflection device for curing the connecting material is coupled into the connecting material between the holding element and the optical element by means of the deflection device. The system for connecting the holding element to the optical element by means of the connecting material is particularly suitable for carrying out the method according to the first aspect.The holding element for connection to the optical element is in particular a holding element according to the second aspect.

[0016] According to a fourth aspect of the present invention, the stated object is achieved for an optical assembly for microlithography comprising: an optical element and a holding element, wherein the holding element is connected to the optical element, in that the optical assembly comprises at least one deflection device for deflecting radiation for curing the connecting material, wherein the deflection device is designed such that radiation incident on the deflection device for curing the connecting material is coupled into the connecting material between the holding element and the optical element by means of the deflection device. The optical assembly is produced in particular according to a method according to the first aspect. The optical assembly comprises in particular a holding element according to the second aspect.

[0017] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below.

[0018] According to a first advantageous embodiment of the present invention, the radiation for curing the bonding material is deflected by means of the deflection device for deflecting the radiation transversely through the optical element in the direction of the bonding material. The deflection device for deflecting the radiation is in particular designed to deflect the radiation for curing the bonding material transversely through the optical element in the direction of the bonding material. For example, the deflection device can be arranged such that radiation striking the deflection device for curing the bonding material is deflected by means of the deflection device in such a way that the radiation is coupled into the optical element and guided in the direction of the bonding material. The optical element can in particular function as a light guide. The radiation can then be guided through the optical element in the direction of the bonding material.In particular, the radiation for curing the bonding material can be guided through the optical element to a connection point to which the bonding material is applied. The radiation for curing the bonding material can then be at least partially coupled into the bonding material to cure the bonding material. Because the radiation for curing the bonding material is deflected transversely through the optical element by means of the deflection device, the radiation can be coupled into the bonding material regardless of the shape of the optical element, in particular transversely.

[0019] According to a further advantageous embodiment of the present invention, the optical element has at least one optical surface and one side surface. An optical element generally has a front surface, a rear surface, and a side surface. An optical surface can be understood to be a surface through which radiation passes during use of the optical element, for example during operation of an optical system comprising the optical element. Radiation usually does not pass through the side surface of an optical element. Rather, the side surface delimits the optical element laterally. A side surface of a rotationally symmetrical optical element, such as a lens, can be understood to be, in particular, the edge cylinder of the optical element. The axis of the edge cylinder of the optical element is generally parallel to the axis of rotation of the optical element.In a lens, the useful radiation first passes through the front surface and then the rear surface, with the front and rear surfaces being designed as optical surfaces. The optical element is connected, in particular glued, to a retaining element via the side surface.

[0020] Preferably, the radiation for curing the bonding material is coupled into the optical element via the side surface of the optical element by means of the deflection device for deflecting the radiation. The deflection device can in particular be arranged such that the radiation for curing the bonding material is coupled into the optical element via the side surface of the optical element by means of the deflection device. It is conceivable, for example, that the deflection device is arranged adjacent to the optical element, in particular the side surface of the optical element. Because the radiation is coupled into the optical element via the side surface of the optical element by means of the deflection device, the radiation for curing the bonding material can be coupled into the optical element regardless of the shape of the optical surfaces of the optical element.In particular, the radiation source can be positioned independently of the geometry of the optical surfaces of the optical element. It has been shown that more power can be provided through indirect irradiation, regardless of the shape of the optical element. For biconvex lenses in particular, this allows approximately 15 times the power to be provided for the same input power of the radiation source compared to the connection method known from the prior art. With the help of the invention, additional degrees of freedom can be achieved in process design and optical design. The higher efficiency also enables a shorter exposure time.

[0021] The deflection device is arranged, for example, at least approximately at a 45° angle to the side surface of the optical element. It is conceivable, for example, that the radiation for curing the bonding material is directed at least substantially perpendicularly onto the side surface of the optical element by means of the deflection device. In particular, the deflection device is aligned at a 45° angle to the line of sight to the connection point. The side surface can have a certain roughness. Radiation impinging on the side surface can, for example, be randomly scattered.

[0022] In the optical element, reflections, particularly total internal reflection, can occur more frequently on the optical surfaces, so that the optical element acts as a light guide. This focuses the light on the opposite side of the optical element.

[0023] According to a further advantageous embodiment of the present invention, the connecting material is applied to at least one connection point between the holding element and the optical element. For example, the connecting material is applied to the optical element and / or the holding element. It is conceivable, for example, that the connecting material is applied flatly to at least one connection point, in particular to the optical element and / or the holding element. By means of the connecting material, a material-to-material connection can be produced at at least one connection point between the optical element and the holding element. The deflection device for deflecting the radiation for curing the connecting material can preferably be arranged at least substantially opposite the at least one connection point between the holding element and the optical element.This is particularly advantageous for an optical element designed as a lens, since the symmetry results in self-focusing effects, in particular a tendency to focus on the opposite connecting means, in particular in the opposite adhesive gap. For other optical elements, other positions may be more advantageous. The deflection device is arranged in particular on a side of the optical element that is at least substantially opposite the connection point. In particular, by means of the deflection device, radiation for curing the connecting material is directed onto an entry point on the optical element that is at least substantially opposite the connection point.

[0024] The connecting material is preferably applied to a plurality of connection points between the holding element and the optical element. A plurality of connection points here means in particular two or more connection points. The connecting material is preferably applied to at least three connection points between the holding element and the optical element. A deflection device for deflecting the radiation for curing the connecting material is preferably arranged at least substantially opposite the connection points, in particular on a substantially opposite side of the optical element. It is conceivable, for example, that the connecting material is applied to six connection points between the holding element and the optical element, wherein six deflection devices arranged substantially opposite one another are provided.By means of the deflection devices, radiation can be coupled transversely into the connection points to cure the connecting material. It is also conceivable, for example, for the connecting material to be applied to three connection points, with three deflection devices arranged essentially opposite one another. This results in symmetry, whereby a certain degree of self-focusing of the radiation coupled into the optical element can be achieved. The self-focusing is essentially based on the shape of the optical surfaces, in particular the top and bottom, of the optical element. In particular, when the radiation enters the optical element, a large number of total reflections at the optical surfaces and random scattering on the side surface of the optical element result in increased intensity on the opposite side. The random scattering depends in particular on the roughness of the side surface.The roughness, due to the statistics of the large number of scattered rays, causes a homogenization of the radiation intensity on the opposite side. This makes it possible to achieve uniform illumination, which is advantageous for the polymerization of the bonding material. The side surface of a rotationally symmetrical optical element, such as a lens, can be understood in particular as the edge cylinder of the optical element. In the case of a lens, the side surface is thus at least essentially circular when viewed in the direction of the useful light. The radiation path can, for example, lead through the center of the optical element, which can lead to higher intensities at the bonding points.

[0025] According to a further advantageous embodiment of the present invention, the deflection device is at least partially designed to reflect the radiation for curing the joining material. For example, it is conceivable that the deflection device reflects radiation for curing the joining material in the direction of the joining material. The deflection device comprises, in particular, at least one reflective element. A reflective element is, in particular, designed to at least partially reflect radiation. For example, a reflective element can be understood to be a mirror surface or a tool with a mirror surface. The reflective element has, in particular, a shape and / or orientation that can provide the highest possible light yield and / or the most uniform possible illumination in the connection point.The reflective element, in particular, has a high reflectivity for the excitation radiation. In particular, the deflection device is essentially designed as a reflector, in particular for a spectral range of the electromagnetic spectrum, in particular for a spectral range matching the connecting material.

[0026] According to a further advantageous embodiment of the present invention, the deflection device comprises at least one optical fiber for deflecting the radiation for curing the bonding material. Optical fibers can be understood as, for example, transparent fibers, in particular glass fibers, tubes or cables that transport radiation. The light is guided in particular by reflection at the boundary surface of the optical fiber, by total internal reflection due to a lower refractive index of the medium surrounding the optical fiber, by mirroring the boundary surface and / or by a suitable refractive gradient. Optical fibers allow for particularly flexible deflection of the radiation for curing the bonding material. It is conceivable, for example, that the at least one optical fiber is at least partially curved.For example, the light guide is bent substantially at a 90° angle in order to couple radiation from a radiation source arranged above the optical element and / or the holding element, transversely into the connection point, in particular via a side surface of the optical element. One end of the light guide can, for example, border on a side surface of the optical element in order to couple radiation transversely through the optical element into a connection point. It is conceivable, for example, that the end of the light guide borders on the side surface of the optical element on a side of the optical element opposite the connection point. Another end of the light guide can, for example, border on the radiation source. It is also conceivable that the holding element has a recess through which the light guide extends at least partially.In this way, one end of the light guide can, for example, be adjacent to or brought into contact with a side surface of the optical element. A light guide can, in particular, be a rigid light guide, such as a light rod.

[0027] According to a further advantageous embodiment of the present invention, the deflection device for deflecting the radiation is detachably connected to the holding element. The deflection device for deflecting the radiation for curing the connecting agent can, for example, be provided temporarily. The deflection device for deflecting the radiation for curing the connecting material is provided in particular for the duration of the irradiation for curing the connecting agent. It is conceivable, for example, that the deflection device is suitable for detachable connection to the holding element. The deflection device can thus, for example, be detachably connected to the holding element for the duration of the irradiation of the connecting agent. A reflective element, e.g. a mirror surface, can be temporarily introduced as a tool for the duration of the curing of the connecting material, in particular opposite a connection point.

[0028] According to a further advantageous embodiment of the present invention, the deflection device for deflecting the radiation is part of the holding element. The holding element has the deflection device for deflecting the radiation, in particular permanently. It is conceivable, for example, that the deflection device is provided as a mirror surface on the holding element. The deflection device can, for example, be permanently connected to the holding element.

[0029] According to a further advantageous embodiment of the invention, the holding element is a mount for receiving the optical element. The mount can, for example, correspond at least partially to the external shape of the optical element in order to be able to receive it in particular with a precise fit. Connecting the mount to the optical element by means of the connecting material can, for example, comprise positioning the optical element in the mount. The side surface of the optical element can, for example, form a gap with the inner surface of the mount, into which gap the connecting material is introduced. When the optical element is aligned in the mount, the connecting material can, for example, be applied to a connection point through the gap. The gap can, for example, form an injection channel for the connecting material.

[0030] According to a further advantageous embodiment of the invention, the system further comprises: a spherical weight for positioning the optical element and the holding element relative to one another. The spherical weight serves in particular for positioning the optical element and a mount relative to one another. For example, it is conceivable that the holding element is held stationary and the optical element is movable relative to the holding element with the aid of the spherical weight. The spherical weight preferably has at least one recess designed such that the radiation for curing the bonding material passes through the recess in the spherical weight to the deflection device for deflecting radiation for curing the bonding material.The spherical weight can, for example, be arranged above the optical element in such a way that the at least one recess in the spherical weight is located above the at least one deflection device for deflecting the radiation for curing the bonding material. The radiation reaches the deflection device, for example, through the recess in the spherical weight. The spherical weight has, in particular, a number of recesses corresponding to the number of deflection devices, so that, for example, a recess can be arranged above each deflection device. It is also conceivable for the spherical weight to have at least one recess which is designed in such a way that the deflection device for deflecting the radiation for curing the bonding material extends at least partially through the recess in the spherical weight.It is particularly conceivable that the deflection device comprises at least one optical fiber for deflecting radiation, which extends at least partially through a recess of the ball weight in order to direct radiation through the recess.

[0031] The system can also have a radiation source for providing the radiation for curing the bonding material. The radiation source is, for example, a UV radiation source, preferably a UV condenser. It is also conceivable that a radiation source for radiation in a different spectral range is used. The bonding material is cured, for example, by rotating the optical assembly and / or the system. In this way, focused illumination can be used. It is also conceivable that the bonding material is cured using annular illumination. This preferably allows exposure, in particular curing, of a plurality of bonding points, in particular all bonding points, to take place simultaneously.

[0032] Furthermore, the system can comprise a connection mount and / or a multi-leg mount, in particular a tripod mount, for positioning the optical element and / or the holding element. It is conceivable, for example, that the optical element can be moved in the multi-leg mount with the aid of the ball weight and / or that the holding element can be displaced laterally on the connection mount. The multi-leg mount can comprise a plurality of support elements with support surfaces on which the optical element can rest. For example, it can be a tripod mount with three support elements. It is conceivable, for example, that the holding element, the optical element, the connection mount and / or the multi-leg mount are rotated on an air bearing about the optical axis of the optical element during irradiation, such that a plurality of connection points can be irradiated evenly.

[0033] The system can further comprise a measuring system for determining the relative positions of the holding element and the optical element. For example, the measuring system can be used to determine the position of the optical element in the coordinate system of the holding element, which is designed as a mount.

[0034] The exemplary embodiments of the present invention described above in this specification are also to be understood as disclosed in all combinations with one another. The individual features of each aspect can be combined with any or all features of the other aspects. Further embodiments and advantages of the invention are explained in the following detailed description of some exemplary embodiments of the present invention in conjunction with the drawings. Short description of the drawing

[0035] In the following, exemplary embodiments and variants of the invention are explained in more detail with reference to the drawings. The aspects of the disclosure can best be understood from the following detailed description in conjunction with the accompanying figures. The figures are schematic and simplified, showing only details to improve the understanding of the claims, while other details are omitted. The same reference numerals are used throughout for identical or corresponding parts. The individual features of each aspect can each be combined with any or all features of the other aspects. These and other aspects, features and / or technical effects are apparent from and are clarified by the figures described below. It shows Fig. 1 is a schematic representation of a system for connecting a lens mount to a lens according to the prior art, Fig. 2 the acceptance of the angles of incidence of UV light depending on different lens geometries according to the state of the art, Fig. 3 a schematic representation of an embodiment of a system according to the third aspect, Fig. 4 a schematic representation of another embodiment of a system according to the third aspect, Fig. 5a, Fig. 5b is a schematic representation of another embodiment of a system according to the third aspect, Fig. 6a, Fig. 6b a schematic plan view of further embodiments of a system according to the third aspect, Fig. 7a, Fig. 7b a schematic plan view and perspective view of a further embodiment of a system according to the third aspect, and Fig. 8 a schematic representation of another embodiment of a system according to the third aspect.

[0036] In Fig. 1 shows a system 10' known from the prior art for connecting a lens mount 1' to a lens 2'. The lens 2' is glued into the lens mount 1' at a bonding point 6' using a UV-curable adhesive 3'. UV light 4' from a UV light source (not shown) is irradiated onto the bonding point 6' to cure the adhesive 3'. After the lens 2' has been positioned in the lens mount 1', the UV light source is positioned such that the UV light 4' is coupled into the lens 2' through the upper optical surface 2a' of the lens 2' and the focus of the UV light source is imaged on the side surface 2c' of the lens 2'. Manual positioning of the UV light source can lead to deviations in position and angle.

[0037] As in Fig. As shown in Figure 2, different lens geometries accept different angles of incidence α', β' for coupling the UV light 4' into the adhesive 3' at the bonding point 6'. For example, lenses with convex optical surfaces 2a, 2b are particularly poorly suited for coupling light 4' for adhesive curing. The method known from the prior art can therefore limit the implementation of an optical design and can result in fluctuations in the strength of the adhesive 3'. This can result in positional drifts of the optical element, which can jeopardize the actual function of the product.

[0038] In Fig. 3 shows an embodiment of a system 10 for connecting a holding element 1, which is designed as a mount 1a, to an optical element 2 by means of a connecting material 3 according to the present invention. The system 10 comprises the mount 1a and a transparent optical element 2, which is designed as a biconvex lens. The optical element 2 is received in the mount 1a. The optical element 2 has two opposing convex optical surfaces 2a, 2b and a side surface 2c. To connect the optical element 2 to the holding element 3, a connecting material 3, here a UV-curable adhesive, is applied to a connection point 6 between the side surface 2c of the optical element 2 and the inner surface of the mount 1a. The connecting material 3 is irradiated with radiation 4 to cure the connecting material 3.The radiation 4 for curing the bonding material 3 is provided by the radiation source 14.

[0039] The radiation 4 from the radiation source 14 for curing the connecting material 3 is coupled into the optical element 2 via the side surface 2c of the optical element 2 by means of the deflection device 5 for deflecting the radiation 4, deflected transversely through the optical element 2 in the direction of the connecting material 3, and coupled into the connecting material 3 for curing the connecting material 3. The holding element 1 for connection to the optical element 2 by means of the connecting material 3 comprises the deflection device 5 for deflecting radiation 4 for curing the connecting material 3. The deflection device 5 is designed as a reflective element 7, in particular as a mirror surface, which is part of the holding element 1.The deflection device 5 is arranged at least substantially opposite the connection point 6 and is designed such that radiation 4 incident on the deflection device 5 is coupled into the connection material 3 between the holding element 1 and the optical element 2 by means of the deflection device 5 to cure the connection material 3. It has been shown that more power can be made available through indirect irradiation, regardless of the shape of the optical element 2. In particular, for biconvex lenses, with the same input power of the radiation source 14, approximately 15 times the power can be made available compared to the connection method known from the prior art. The higher efficiency also enables a shorter exposure time.

[0040] With the aid of the system 10, an optical assembly 11 for microlithography comprising the optical element 2, the holding element 1, which is connected to the optical element 2, and the deflection device 5, which is configured to deflect radiation 4 for curing the bonding material 3, can be produced. Fig. 4 shows a further embodiment of a system 10 for connecting a holding element 1 to an optical element 2 by means of a connecting material 3 according to the present invention. In addition to the transparent optical element 2 and a holding element 1 for connection to the optical element 2, the system 10 comprises a deflection device 5 for deflecting radiation 4 for curing the connecting material 3. The deflection device 5 is designed such that radiation 4 incident on the deflection device 5 for curing the connecting material 3 is deflected by the deflection device 5 transversely through the optical element 2 and coupled into the connecting material 3 between the holding element 1 and the optical element 2. The optical element 2 functions as a light guide 15. In the optical element 2, total reflections occur at the optical surfaces. This can create a focus on the opposite side of the optical element 2.The deflection device 5 is only temporarily inserted into the system 10 as a tool for the duration of the irradiation of the bonding material 3. The deflection device 5 can, for example, be detachably connected to the holding element 1 and removed again after the irradiation of the bonding material 3. The curing of the bonding material 3 can take place while rotating the system 10. Alternatively, it is conceivable that the bonding material can be cured using annular illumination.

[0041] In the Fig. 5a and Fig. Figure 5b shows a further embodiment of a system 10 for connecting a holding element 1 to an optical element 2 by means of a connecting material 3 according to the present invention. The system 10 comprises a holding element 1, which is designed as a mount 1a for receiving the optical element 2. The optical element 2 is received in the mount 1a. The side surface 2c of the optical element 2 forms a gap 12 with the inner surface of the mount 1a, into which gap the connecting material 3 is introduced. On the side of the optical element 2 substantially opposite the gap 12, a deflection device 5 is arranged for deflecting radiation 4 for curing the connecting material 3.

[0042] The position of the optical element 2 in the coordinate system of the mount 1a is determined by means of a measuring system (not shown). Furthermore, a connection receptacle 13 for positioning the holding element 1 and a multi-leg receptacle 16 for positioning the optical element 2 are provided. The multi-leg receptacle 16 has support elements distributed over the circumference of the optical element 2 with support surfaces for supporting the optical element 2 in the mount 1a. A ball weight 9 is also provided for positioning the optical element 2 and the mount 1a relative to one another. With the aid of the ball weight 9, the optical element 2 can be moved in the multi-leg receptacle 16 and the holding element 1 can be displaced laterally on the connection receptacle 13. Once the optical element 2 is approximately aligned with the mount 1a, the connecting material 3 can be applied to the connection point 6 through the gap 12, which forms an injection channel.

[0043] After the position of the optical element 2 has been finely adjusted again, radiation 4 for curing the bonding material 3 is provided by the radiation source 14, which is designed here as a UV condenser. The ball weight 9 has a recess 9a, which is arranged above the deflection device 5 for deflecting radiation 4 for curing the bonding material 3, so that the radiation 4 from the radiation source 14 passes through the recess 9a of the ball weight 9 to the deflection device 5. The deflection device 5, which is designed as a reflective element 7 for reflecting the radiation 4 for curing the bonding material 3, is arranged such that the radiation 4 from the radiation source 14 passes transversely through the optical element 2 to the connection point 6.

[0044] In the Fig. 6a and Fig. 6b shows further embodiments of systems 10 for connecting a holding element 1 to an optical element 2 by means of a connecting material 3. A plurality of connection points 6 are provided between the holding element 1 and the optical element 2, wherein a deflection device 5 for deflecting the radiation 4 for curing the connecting material 3 is arranged on an at least substantially opposite side of the optical element 2 at each of the connection points 6. Fig. 6a, three deflection devices 5 are provided for deflecting radiation 4 toward three opposite connection points 6. This results in a symmetry, whereby a certain self-focusing of the coupled radiation 4 can be achieved. Fig. 6b, six deflection devices 5 are provided for deflecting radiation 4 toward six essentially opposite connection points 6. The optical element 2 can thus be connected to the mount 1a at several connection points 6 along the side surface 2c of the optical element 2. For example, UV-curable adhesive can be used as the connecting means 3, which is irradiated by UV radiation 4 from a UV radiation source 14 for curing.

[0045] In the Fig. 7a and Fig. Figure 7b shows a further embodiment of a system 10 for connecting a holding element 1 to an optical element 2 by means of a connecting material 3. Three connection points 6 are provided between the holding element 1 and the optical element 2. An end 8a of a light guide 8 is arranged opposite each of the connection points 6. By means of the light guides 8, radiation from a radiation source (not shown) is deflected at an angle of almost 90° and coupled into the optical element 2 opposite the respective connection point 6. The light guides 8 extend at least partially through recesses 1b in the holding element 1. In this way, the ends 8a of the light guides 8 come close to the edge cylinder of the optical element 2. The light guides 8 also extend at least partially through a recess 17a of a mimic 17, which determines the arrangement of the light guides 8.

[0046] In Fig.8 shows a further embodiment of a system 10 for connecting a holding element 1, which is designed as a mount 1a, to a transparent optical element 2 by means of a connecting material 3 according to the present invention. To connect the optical element 2 to the holding element 3, the connecting material 3 is applied between the optical element 2 and the holding element 1. The radiation 4 for curing the connecting material 3 is provided by a radiation source (not shown). The radiation 4 is deflected by means of a light guide 8 onto a reflective element 7, which is designed in particular as a mirror surface, and is coupled by means of the reflective element 7 via a side surface of the optical element 2 transversely into the optical element 2 and finally into the connecting material 3. The light guide 8 is, for example, a rigid light guide, in particular a light rod.It is conceivable that a plurality of optical fibers 8 and correspondingly arranged reflective elements 7 are provided in order to couple radiation into a corresponding number of connection points 6. Alternatively, it is conceivable, for example, that only one optical fiber 8 is provided, which is rotated in order to direct radiation onto a plurality of reflective elements 7, which in turn redirect this radiation in the direction of the connection points 6.

Claims

[1] Method for connecting a holding element (1) to an optical element (2) by means of a connecting material (3), comprising the steps: - arranging the connecting material (3) between the holding element (1) and the optical element (2), and - curing the connecting material (3), wherein the connecting material (3) is irradiated with radiation (4) for curing the connecting material (3), characterized by that the radiation (4) for curing the connecting material (3) is coupled into the connecting material (3) by means of a deflection device (5) for deflecting the radiation (4). [2] Method according to claim 1, characterized by that the radiation (4) for curing the connecting material (3) is deflected by means of the deflection device (5) for deflecting the radiation (4) transversely through the optical element (2) in the direction of the connecting material (3). [3] Method according to claim 1 or 2, characterized bythat the optical element (2) has at least one optical surface (2a, 2b) and one side surface (2c), wherein the radiation (4) for curing the connecting material (3) is coupled into the optical element (2) via the side surface (2c) of the optical element (2) by means of the deflection device (5) for deflecting the radiation (4). [4] Method according to one of claims 1 to 3, characterized by that the connecting material (3) is applied to at least one connection point (6) between the holding element (1) and the optical element (2), wherein the deflection device (5) for deflecting the radiation (4) for curing the connecting material (3) is arranged at least substantially opposite the at least one connection point (6) between the holding element (1) and the optical element (2). [5] Method according to claim 4, characterized bythat the connecting material (3) is applied to a plurality of connecting points (6) between the holding element (1) and the optical element (2), wherein a deflection device (5) for deflecting the radiation (4) for curing the connecting material (3) is arranged at least substantially opposite the connecting points (6). [6] Method according to one of claims 1 to 5, characterized by that the deflection device (5) is at least partially designed to reflect the radiation (4) for curing the connecting material (3), in particular comprises at least one reflective element (7). [7] Method according to one of claims 1 to 6, characterized by that the deflection device (5) comprises at least one light guide (8) for deflecting the radiation (4) for curing the connecting material (3). [8] Holding element (1) for connection to an optical element (2) by means of a connecting material (3), in particular for use in a method according to one of claims 1 to 7, characterized by that the holding element (1) comprises at least one deflection device (5) for deflecting radiation (4) for curing the connecting material (3), wherein the deflection device (5) is designed such that radiation (4) impinging on the deflection device (5) for curing the connecting material (3) is coupled into the connecting material (3) between the holding element (1) and the optical element (2) by means of the deflection device (5). [9] Holding element (1) according to claim 8, characterized by that the deflection device (5) for deflecting the radiation (4) is detachably connected to the holding element (1). [10] Holding element (1) according to claim 8, characterized by that the deflection device (5) for deflecting the radiation (4) is part of the holding element (1). [11] Holding element according to one of claims 8 to 10, characterized by that the holding element (1) is a socket (1a) for receiving the optical element (2). [12] System (10) for connecting a holding element (1) to an optical element (2) by means of a connecting material (3), in particular for carrying out a method according to one of claims 1 to 7, comprising: - an optical element (2), and - a holding element (1), in particular a mount (1a), for connection to the optical element (2), in particular a holding element (1) according to one of claims 8 to 11, characterized bythat the system (10) comprises at least one deflection device (5) for deflecting radiation (4) for curing the connecting material (3), wherein the deflection device (5) is designed such that radiation (4) impinging on the deflection device (5) for curing the connecting material (3) is coupled into the connecting material (3) between the holding element (1) and the optical element (2) by means of the deflection device (5). [13] System (10) according to claim 12, characterized by that the system (10) further comprises: - a ball weight (9) for positioning the optical element (2) and the holding element (1), in particular the mount (1a), relative to one another, wherein the ball weight (9) has at least one recess (9a) which is designed such that the radiation (4) for curing the connecting material (3) passes through the recess (9a) of the ball weight (9) to the deflection device (5) for deflecting radiation (4) for curing the connecting material (3) and / or that the deflection device (5) for deflecting the radiation (4) for curing the connecting material (3) extends at least partially through the recess (9a) of the ball weight (9). [14] Optical assembly (11) for microlithography, in particular manufactured according to a method according to one of claims 1 to 7, comprising: - an optical element (2), and - a holding element (1), in particular a holding element (1) according to one of claims 8 to 11, wherein the holding element (1) is connected to the optical element (2), characterized by that the optical assembly (11) comprises at least one deflection device (5) for deflecting radiation (4) for curing the connecting material (3), wherein the deflection device (5) is designed such that radiation (4) impinging on the deflection device (5) for curing the connecting material (3) is coupled into the connecting material (3) between the holding element (1) and the optical element (2) by means of the deflection device (5).

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