Method for joining optical elements by blasting

Abstract

A method for joining a first optical element (113) to a second optical element (114) by blasting to produce a composite optical component (106). The first optical element (113) has a first contact surface (115) and the second optical element (114) has a second contact surface (116), wherein the first contact surface (115) and the second contact surface (116) are suitable for blasting, and wherein the optical component (106) is intended to be used at an operating temperature in an optical system (100) such that a beam path (101) of the optical system (100) passes through the contact surfaces (115, 116) of the optical elements (113, 114). The method comprises the steps: - active temperature control of the first optical element (113) until a first target temperature is reached, - active temperature control of the second optical element (114) until a second target temperature is reached, - Joining the tempered optical elements (113, 114) by bringing the contact surfaces of the first optical element (113) and the second optical element (114) into contact in order to blast the first optical element (113) onto the second optical element (114). This method makes it possible to reduce or even avoid tension in the contact areas.

Description

[0001] The present invention relates to a method for joining optical elements by wringing. The invention further relates to the use of an optical component produced by the method for interferometrically measuring the imaging quality of an imaging system.

[0002] The process of wringing is fundamentally known from the prior art. During wringing, two joining partners whose contact surfaces have essentially the same geometry and a sufficiently smooth surface are brought closer together until the contact surfaces are in direct contact. In this state, the contact surfaces are held together by molecular forces of attraction - i.e., without a joining agent such as an adhesive. Wringing is used in particular in the field of optics to connect optical elements such as lenses or mirrors to one another or to other components or holders (cf. WO 2022 / 218793). In particular, wringing enables simple and releasable fixing of optical elements at desired positions within an optical system.

[0003] It has been shown that optical components in demanding applications (for example, in the field of microlithography), in which a beam path passes through the contact surfaces of the optical elements connected by means of bonding, often cannot be manufactured with sufficiently high and reproducible quality. Against this background, the object of the present invention is to provide a method for bonding two optical elements together, with which optical components of improved quality can be obtained. This object is achieved by the subject matter of the independent claims. Advantageous embodiments are described in the subclaims.

[0004] Accordingly, the invention relates to a method for joining a first optical element to a second optical element by wringing to produce a composite optical component. The first optical element has a first contact surface, and the second optical element has a second contact surface, wherein the first contact surface and the second contact surface are suitable for wringing. The optical component is intended to be used at an operating temperature in an optical system such that a beam path of the optical system passes at least partially through the contact surfaces of the optical elements. The method comprises the steps: - actively tempering the first optical element until a first target temperature is reached, - actively tempering the second optical element until a second target temperature is reached, - Joining the tempered optical elements together by bringing the contact surfaces of the first optical element and the second optical element into contact in order to weld the first optical element to the second optical element.

[0005] First, some terms used in the context of the invention will be explained. The "active temperature control" of the optical elements is achieved through deliberate and targeted measures in addition to passive temperature influences from the environment. If the contact surfaces are suitable for wringing, this means that they are sufficiently smooth and have a sufficiently consistent geometry so that a wringing process is possible. The contact surfaces of the optical elements can be flat, planar surfaces. However, it is also possible for the contact surfaces to be corresponding curved surfaces.

[0006] Within the scope of the invention, it was recognized that the optical quality in the region of the contact surfaces can be improved by actively controlling the temperature of the optical elements, and the reproducibility of the achievable quality level can also be increased. In particular, it was recognized that uncontrolled deviations between the temperatures of the optical elements during wringing can lead to uncontrolled thermal expansion of the optical elements upon subsequent adjustment of the temperatures (in particular during subsequent temperature control of the optical elements until the operating temperature of the optical system is reached). This can, in particular, lead to lateral distortion in the region of the contact surface between the optical elements, which impairs the optical quality of the assembled optical component.Distortion is a linear measure and indicates the deviation of the structural points of the optical element from their target positions. By actively controlling the temperatures of the optical elements to the desired target temperatures during the wringing process, significantly better and more reproducible results can be achieved.

[0007] The active temperature control of an optical element can be achieved, for example, by bringing the optical element into contact with a temperature control plate that has the desired target temperature. It can be provided that the first optical element is actively temperature-controlled to the first target temperature during assembly, and the second optical element is actively temperature-controlled to the second target temperature during assembly. Devices used to manipulate the optical elements during assembly can be temperature-controlled to the respective target temperature. Furthermore, it can be provided that the first target temperature and the second target temperature coincide with a common target temperature. The assembly process can take place within an atmosphere that is temperature-controlled to the common target temperature.

[0008] It is possible for a material of the first optical element to have a thermal expansion coefficient that differs from the thermal expansion coefficient of the material of the second optical element. The thermal expansion coefficients can differ from one another, for example, by a factor of more than 2, in particular more than 5, and more particularly by a factor of more than 10. The above information relates to the thermal expansion coefficient that can be determined under normal pressure at a temperature of 20°C. If the temperature of the optical elements deviates from the later operating temperature during wringing, it can happen that one of the optical elements changes its dimensions more than the other optical element, which, in particular when there are large differences between the thermal expansion coefficients, can lead to mechanical stress in the region of the contact surface orcan lead to distortion within the assembled optical component. Therefore, one embodiment provides for the first target temperature and the second target temperature to coincide with the operating temperature. By ensuring that the optical elements are at the same temperature during wringing and later used in an optical system at the same temperature, distortion caused by thermal expansion can be reduced or avoided.

[0009] Within the scope of the invention, however, it was recognized that distortion can occur in the region of the contact surfaces even though the optical elements were tempered to the operating temperature intended for later use during wringing. Such distortion, which is also referred to below as "initial distortion", can be caused, for example, by dynamic processes occurring during wringing. During the wringing process, a layer of air present between the contact surfaces usually has to be displaced first. The connecting partners are therefore usually first brought closer to one another in a partial area of ​​the contact surfaces until contact occurs in the partial area and a concomitant sudden application of force between the connecting partners in this partial area. This can possibly lead to local and, for example, elastic deformation of at least one of the connecting partners.Starting from the area already in contact, the contact surfaces are brought closer together, further displacing any remaining air layers, until full-surface contact is established between the contact surfaces. It is assumed that the dynamic processes occurring in the area of ​​the contact surfaces can cause initial distortion in the material of the joining partners.

[0010] Against this background, according to one embodiment, it is proposed that at least one of the first target temperature and the second target temperature deviates from the later operating temperature, wherein the first target temperature and / or the second target temperature are determined taking into account a thermal expansion coefficient of the first optical element, and / or taking into account a thermal expansion coefficient of the second optical element, and / or taking into account a thermal expansion coefficient of the optical component after joining. The thermal expansion coefficient of the optical component after joining the first and second optical elements can be determined in a fundamentally known manner using a finite element simulation. Thus, the fact that the optical elements experience an uneven change in length when heating up (or cooling down) to the later operating temperature is deliberately exploited.This generally applies both when the materials of the optical elements have different thermal expansion coefficients and when the materials of the optical elements have the same thermal expansion coefficients. In the latter case, the first target temperature can differ from the second target temperature in order to deliberately achieve different changes in the length of the optical elements. Initial distortion can be counteracted by the unequal linear expansion. If, for example, the initial distortion leads to a displacement of structural points of the first optical element starting from a center outwards, an appropriate selection of the first and second target temperatures can bring about unequal linear expansion, which leads to an opposite displacement of the structural points of the first optical element inwards towards the center.

[0011] In one embodiment, it is provided that at least one of the optical elements has a reference temperature at which the at least one of the optical elements is distortion-free, wherein a target temperature of the at least one of the optical elements is selected taking the reference temperature into account. For example, the target temperature can be selected such that it deviates from the reference temperature. Distortion then occurs even during the tempering of the optical element to the target temperature, the extent of which depends on the difference between the reference temperature and the target temperature. By selecting a suitable deviation of the target temperature from the reference temperature, initial distortion that occurs due to the dynamic processes mentioned above can be counteracted.Depending on the application, the target temperature can also be selected so that it matches the reference temperature. In this case, additional distortion is avoided.

[0012] It can be provided that the first target temperature and the second target temperature are selected such that an initial distortion of at least one of the optical elements occurring during wringing is at least partially compensated. The first target temperature and the second target temperature can be selected taking into account a thermal expansion coefficient of the first optical element and a thermal expansion coefficient of the second optical element. The first target temperature and the second target temperature can also be selected taking into account a thermal expansion coefficient of the optical component after assembly.

[0013] In one embodiment, it can further be provided that the initial distortion of at least one of the optical elements occurring during wringing is estimated by an experimental comparison test and / or by a theoretical calculation. An estimation based on a comparison test can be carried out, for example, by producing optical test elements that correspond to the first optical element and the second optical element, wherein at least one of the optical test elements is provided with a two-dimensional test pattern in the region of the contact surfaces, which extends along the contact surface. The test pattern can, for example, have test structures that are a certain distance from one another. The positions of the test structures of the test pattern before and after wringing can be determined.If distortion of at least one of the optical test elements occurs during the wringing process, this can be determined based on a change in the test pattern and, in particular, based on a change in the positions of the test structures. This change represents a measure of the distortion of the respective optical test element. From the observed distortion, a conclusion can be drawn about the distortion of a corresponding optical element used in the present method.

[0014] Furthermore, distortion of an optical element caused by the selection of the first target temperature and the second target temperature, which results when the component is heated to operating temperature, can be estimated through an experimental comparison test and / or a theoretical calculation. In this case, too, optical test elements as described above can be used to experimentally determine the effect of heating on the stress using the corresponding test specimens. The theoretical calculation can be performed, in particular, using a finite element simulation. It is also possible to perform a theoretical calculation based on a simplified geometric model.

[0015] In one embodiment, at least one of the optical elements has a two-dimensional pattern structure that extends at least partially along the contact surfaces of the optical elements. If one of the optical elements has a two-dimensional pattern structure, the extent of the distortion can be determined directly by comparing the shape of the pattern structure before and after wringing. The two-dimensional pattern structure can be positioned at a distance from the contact surface of the optical element that is less than 10 mm, in particular less than 5 mm. In one embodiment, the optical element provided with the pattern structure has a thickness that is less than 10 mm, in particular less than 5 mm. The pattern structure can be produced on a side of the first optical element opposite the contact surface.For this purpose, for example, microstructuring methods known in principle from the prior art can be used, wherein the structures can be created in particular by depositing material or by removing material. It is possible for the pattern structure to be suitable for fulfilling an optical function when the optical component is used in the optical system. Alternatively, the pattern structure can also be designed and positioned in such a way that the optical function of the optical component is not disrupted when the optical component is used in the optical system. The thickness of the optical element refers to the dimension of the optical element along the direction that is aligned along a main direction of the beam path when the optical component is used correctly in an optical system.

[0016] In demanding optical applications, such as microlithography, particularly high-resolution imaging systems are used to transfer the structure of a mask (also known as a reticle) to a substrate coated with a light-sensitive layer in a reduced size. The prior art (see, for example, DE 101 09 929 A1) discloses measurement methods for interferometrically measuring the imaging quality of such an imaging system. These methods can be used to determine the imaging quality or to detect possible image errors in the imaging system with spatial resolution. In this known measurement method, a first diffraction grating is arranged in an object plane between an illumination device and the imaging system, while a second diffraction grating is positioned in an image plane between the imaging system and a detector.Illumination beams are directed from known positions onto the first diffraction grating and imaged by the imaging system onto the second diffraction grating, resulting in an interferometric image of the illumination beams, which can be detected by the sensor and enables the image quality to be determined. The known method typically uses illumination beams in the UV range, for example, with a wavelength of 193 nm. To detect the interferometric image in the image plane, it is common practice to first convert the UV radiation into visible light, which can then be detected much more easily by an interferogram sensor, for example, a two-dimensional CCD array sensor. This has proven to be advantageous (see [1].DE 102 53 874 A1, DE 10 2011 006 486 A1), a wavelength conversion material for converting UV light into visible light is positioned at a short distance behind the second diffraction grating such that the interferometric image can be converted into visible light and detected by the sensor. For this purpose, it was generally known from the prior art to bond a glass substrate provided with the second diffraction grating to a substrate carrier made of a wavelength conversion material by wringing.

[0017] Within the scope of the invention, however, it was recognized that the wringing can cause strains that can lead to distortion of the second diffraction grating. Since the imaging system in microlithographic applications is designed to image objects present in the object plane at a greatly reduced size into the image plane, the second diffraction pattern typically exhibits significantly smaller feature sizes than the first diffraction pattern. Even small changes in the second diffraction pattern therefore have a significant impact on the measurement accuracy, significantly complicating the measurement of the imaging system and potentially requiring additional correction efforts.

[0018] With the aid of the method according to the invention, the above-mentioned distortion of the second diffraction grating can be significantly reduced or even completely avoided. For this purpose, the first optical element can be provided with the second diffraction grating. In this case, the second diffraction grating represents a two-dimensional pattern structure that extends at least partially along the contact surfaces of the optical elements. The first optical element can in particular comprise a glass substrate, for example made of quartz glass. The second optical element can be a substrate carrier, as described above, which has or consists of a wavelength conversion material. A thickness of the second optical element can be between 1 mm and 100 mm, in particular between 5 mm and 50 mm, preferably between 10 mm and 30 mm. Distortion of the optical component can be caused by distortion of the two-dimensional pattern structure.Any distortion of the substrate carrier that may occur may be irrelevant for the optical function of the optical component and may be neglected.

[0019] The manufacturing method described above makes it possible to reduce or even avoid distortion of the two-dimensional pattern structure at the intended operating temperature of the optical element, so that the two-dimensional pattern structure or the second diffraction grating is not affected by the wringing process and a high-precision interferometric measurement of the imaging quality of an imaging system is possible.

[0020] The present invention further relates to the use of an optical component produced from a first optical element and a second optical element using the method according to the invention in an optical system for interferometrically measuring the imaging quality of an imaging system. The use can be further developed by further features described above in connection with the method according to the invention and with the known measurement method.

[0021] The invention will now be further illustrated with reference to the accompanying drawings. They show: Fig. 1: a schematic representation of a projection exposure system for microlithography with a projection system as imaging system; Fig. 2: a model representation of an optical system for interferometric measurement of the imaging quality of the imaging system from Fig. 1; Fig. 3: a schematic representation to explain the method according to the invention; Fig. 4: a corresponding vector diagram illustrating a distortion measurement for an exemplary optical component.

[0022] In Fig. Figure 1 shows a schematic and highly simplified representation of a microlithographic DUV projection exposure system. The projection exposure system comprises an exposure beam source 14, an illumination system 10, and a projection system 22.

[0023] The exposure beam source 14 generates electromagnetic radiation in the DUV range, i.e., in particular, with a wavelength between 122 nm and 200 nm. The exposure radiation 17 emanating from the exposure beam source 14 is guided into an object plane 12 by the illumination system 10, so that an object field in the object plane 12 is illuminated with uniform radiation intensity. For reasons of clarity, Fig. 1 only illustrates a single illumination beam 17.

[0024] The illumination system 10 comprises a plurality of beam-shaping elements (such as lenses or mirrors) and is designed in a generally known manner, so that a detailed description is omitted. A photomask 13 is arranged in the object plane 12, which is imaged into an image plane 21 by the projection system 22. The projection system 22 also comprises a plurality of beam-shaping elements and is designed in a generally known manner, so that a detailed description is omitted here as well.

[0025] A structure formed on the photomask 13 is transferred by means of the imaging system 22 onto a radiation-sensitive layer of a wafer 20 arranged in the image plane 21. The Fig. The projection exposure system 1 shown in Figure 1 according to the above description essentially represents known prior art.

[0026] In Fig. 2 schematically shows a system 100 for interferometric measurement of the imaging quality of the imaging system 22. The elements of the system 100 and in particular the imaging system 22 are shown in a highly simplified manner. The determination of interferometric images is carried out starting from an illumination source 111 arranged in an object-side pupil plane of the imaging system 22, with which illumination beams 101 are emitted into the imaging system 22. For reasons of clarity, Fig. 2, only a single illumination beam 101 is shown. The illumination beam 101 is a beam with a wavelength of 193 nm.

[0027] Between the illumination source 111 and the imaging system 22 is an object plane 102 of the imaging system 22, in which a first diffraction grating 103 with light-transmitting and light-opaque regions is located. The illumination beam 101 is scattered at the diffraction grating 103 in a fundamentally known manner, which Fig. 2 is indicated by the "fanned-out" beam 104. The beam 104 enters the imaging system 22 and is imaged by it into the image plane 105 of the imaging system 22.

[0028] Behind the imaging system 22 is an optical component 106 made of a quartz glass substrate 113 and a substrate carrier 114 made of a wavelength conversion material. The quartz glass substrate 113 and the substrate carrier 114 were bonded together using the method according to the invention. Within the scope of the present disclosure, the quartz glass substrate 113 may also be referred to as the first optical element, and the substrate carrier 114 as the second optical element.

[0029] The quartz glass substrate 113 is significantly thinner than the substrate carrier 114 and comprises a second diffraction grating 112, which can also be referred to as a two-dimensional pattern structure within the scope of the present disclosure and which was produced by a microstructuring process in a generally known manner. The two-dimensional pattern structure can extend over the entire quartz glass substrate 113 or over partial regions of the quartz glass substrate 113. A thermal expansion coefficient of the substrate carrier 114 is approximately 14 times the thermal expansion coefficient of the quartz glass substrate 113.

[0030] The optical component 106 is positioned such that the second diffraction grating 112 is located in the image plane 105 of the imaging system 22. The beam path 104 transmitted through the imaging system 22 is diffracted again at the second diffraction grating 112. The resulting diffraction pattern is converted into visible light within the carrier substrate 114 and subsequently detected in an image-side pupil plane 109 by an interferogram sensor 110, which is configured here as a CCD array sensor.

[0031] By manufacturing the optical component 106 using the method according to the invention, distortion of the two-dimensional pattern structure could be significantly reduced or even completely avoided, so that the diffraction grating 112 has very precisely positioned grating structures that enable highly accurate interferometric measurement of the imaging system 22.

[0032] The method according to the invention for connecting a first optical element 113 to a second optical element 114 is explained below with reference to the schematic representation of the Fig. 3 by way of example. The first optical element 113, which in this case is formed by the quartz glass substrate already described above, is placed on a first temperature control plate 120. The temperature control plate 120 is connected to a controller not shown in the figure and can be set to a desired first target temperature. The target temperature can be checked using a temperature sensor 121. Due to heat transfer, the quartz glass substrate 113 is also heated to the desired first target temperature after a certain time. The second optical element 114, which in this case is formed by the substrate carrier already described above, is heated to a second target temperature in an analogous manner using a second temperature control plate 120.After the optical elements 113, 114 have reached the respective target temperature, the optical element 113 is removed from the temperature control plate 120 and connected to the optical element 114 by wringing in a generally known manner. A contact surface 115 of the first optical element 113 is brought into contact with a contact surface 116 of the second optical element 114. It may be provided that the elasticity of the optical element 113 is utilized to initially bring a partial area of ​​the contact surface 115 into contact with the contact surface 116. Starting from the partial area already in contact, the contact surfaces are brought closer together, displacing any air layers that may be present between the contact surfaces, until full-surface contact exists between the contact surfaces. The optical elements 113, 114 are then held together by molecular forces of attraction.

[0033] Based on the two-dimensional pattern structure 112 applied to the first optical element, it is possible to determine the extent of distortion within an optical component 106 produced by wringing, which distortion was generated during the wringing process and / or during a subsequent tempering of the optical component 106. In particular, due to the small thickness of the first optical element 113 or the short distance of the pattern structure from the contact surface 115, mechanical stresses in the region of the contact surface 115 can cause the positions of the structural elements of the pattern structure 112 to shift relative to the respective positions the structural elements occupied prior to wringing. This shift is referred to herein as distortion and can be determined in a generally known manner.

[0034] Fig. 4 shows a corresponding vector diagram in which a distortion measurement is illustrated for an exemplary optical component that was not manufactured by a method according to the invention. In particular, the displacement of the structural elements of the two-dimensional pattern structure compared to a position of the structural elements observed before wringing is illustrated as a function of the position within the optical element 113. The straight arrows drawn in the diagram show the direction of the observed displacement, and the length of the arrows as well as the gray value scale illustrate the extent of the displacement. The gray value scale is normalized to 1. There is no distortion in the central region 130 of the optical element. Maximum distortion in the Fig.4 is approximately 400 nm. The distortion shown here for the exemplary optical component not manufactured according to the invention can be reduced or even completely avoided with the aid of the method according to the invention.

[0035] For this purpose, as mentioned above, experimental comparison tests can be conducted to estimate the influence of using different target temperatures on the distortion that subsequently prevails at operating temperature. Furthermore, a simplified geometric model will be presented below, which allows for a suitable selection of the first target temperature and the second target temperature.

[0036] The following terms are used in the model: T R : Reference temperature of the first optical element at which the first optical element 113 is distortion-free; T1: wringing temperature of the first optical element (first target temperature); T2: wringing temperature of the second optical element (second target temperature); T O : temperature of the optical component after wringing, resulting from equalisation of temperatures T1 and T2; T B : Operating temperature of the optical component; α1: coefficient of thermal expansion of the material of the first optical element; α O : Thermal expansion coefficient of the optical component.

[0037] It is assumed below that the distortion of the optical component is determined by a structural change in the two-dimensional pattern structure of the first optical element 113. A structural change in the second optical element 114 is therefore neglected here, as it does not affect the optical quality of the optical component. It is further assumed for simplicity that the distortion VZ of the optical component is given by the product of a scale M and the length L of the pattern structure: VZ=L⋅M.

[0038] The benchmark is determined by three contributions: M=M1+M2+M3.

[0039] The first contribution M1 depends on the thermal expansion or contraction of the material of the first optical element, which occurs before wringing during tempering from the reference temperature T Rto the contact temperature T1 of the first optical element. This contribution is given by M1=(T1−TR)⋅α1.

[0040] The second contribution M2 depends on the thermal expansion or thermal contraction of the composite optical component, which after wringing occurs due to an equalization of the temperatures of the first optical element and the second optical element to the temperature T O This contribution can be calculated in a generally known manner using a finite element simulation. For simplicity, it is assumed below that the contact temperature of the first optical element T1 and the contact temperature of the second optical element T2 are identical, so that M2 = 0.

[0041] The third contribution M3 depends on the thermal expansion or contraction of the assembled optical component, which after wringing during tempering from the temperature T O to the operating temperature T B takes place: M3=(TB−TO)⋅αO.

[0042] The thermal expansion coefficient of the optical component α O can be determined in a fundamentally known manner using a finite element simulation and based on the known properties of the two optical elements.

[0043] Assuming that the contact temperatures of the first optical element and the second optical element are identical (T1 = T2 = T0), the following results for the scale: M=(α1−αO)⋅T1+TB⋅αO−TR⋅α1 or M(T1)=m⋅T1+c, where m and c are constants. Consequently, the scale M and thus the distortion VZ can be set to any value by appropriately selecting the common irradiation temperature (T1 = T2) within the framework of the geometric model.

[0044] Using the model explained above, it is thus possible to select the target temperature during the wringing process in such a way that distortion within the first optical element is at least partially or even completely avoided. To compensate for initial distortion caused by dynamic processes during the wringing process, the model can be used to determine a suitable target temperature that counteracts the initial distortion, i.e., in particular, has an opposite sign. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] WO 2022 / 218793

[0002] DE 101 09 929 A1

[0016] DE 102 53 874 A1

[0016]

Claims

[1] A method for joining a first optical element (113) to a second optical element (114) by wringing to produce a composite optical component (106), wherein the first optical element (113) has a first contact surface (115) and the second optical element (114) has a second contact surface (116), wherein the first contact surface (115) and the second contact surface (116) are suitable for wringing, wherein the optical component (106) is intended to be used at an operating temperature in an optical system (100) such that a beam path (101) of the optical system (100) passes through the contact surfaces (115, 116) of the optical elements (113, 114), characterized by the steps: - actively tempering the first optical element (113) until a first target temperature is reached, - actively tempering the second optical element (114) until a second target temperature is reached, - joining the tempered optical elements (113, 114) by bringing the contact surfaces of the first optical element (113) and the second optical element (114) into contact in order to weld the first optical element (113) to the second optical element (114). [2] Method according to claim 1, characterized by that the first optical element (113) is actively tempered to the first target temperature during assembly and the second optical element (114) is actively tempered to the second target temperature during assembly. [3] Method according to one of claims 1 or 2, characterized byin that a material of the first optical element (113) has a thermal expansion coefficient which differs from the thermal expansion coefficient of a material of the second optical element (114), wherein the thermal expansion coefficient of the first material preferably differs from the thermal expansion coefficient of the second material by a factor of more than 2, more preferably by a factor of more than 5, more preferably by a factor of more than 10. [4] Method according to one of claims 1 to 3, characterized by that the first target temperature and the second target temperature match the operating temperature. [5] Method according to claims 1 to 3, characterized bythat the first target temperature and / or the second target temperature deviate from the operating temperature, wherein the first target temperature and / or the second target temperature are determined taking into account at least one of the following parameters: - a thermal expansion coefficient of the first optical element (113), - a thermal expansion coefficient of the second optical element (114), and - a thermal expansion coefficient of the optical component (106) after assembly. [6] Method according to one of claims 1 to 5, characterized by that at least one of the optical elements (113, 114) has a reference temperature at which the at least one of the optical elements (113, 114) is distortion-free, wherein the first target temperature and / or the second target temperature are selected taking into account the reference temperature of the at least one of the optical elements (113, 114). [7] Method according to claim 5 or 6, characterized by that the first target temperature and the second target temperature are selected such that an initial distortion of at least one of the optical elements (113, 114) is at least partially compensated. [8] Method according to claim 7, characterized by that the initial distortion of at least one of the optical elements (113, 114) occurring during wringing is estimated by an experimental comparison test and / or by a theoretical calculation. [9] Method according to one of claims 5 to 8, characterized by that a distortion of at least one of the optical elements (113, 114) caused by the selection of the first target temperature and the second target temperature, which results when the component (106) is tempered to the operating temperature, is estimated by an experimental comparison test and / or by a theoretical calculation. [10] Method according to one of claims 1 to 9, characterized by that at least one of the optical elements (113, 114) has a two-dimensional pattern structure (112) which extends at least partially along the contact surfaces of the optical elements (113, 114). [11] Method according to claim 10, characterized by that the optical element (113) provided with the two-dimensional pattern structure (112) has a thickness which is less than 10 mm, in particular less than 5 mm. [12] Method according to one of claims 1 to 11, characterized by that the optical system (100) is designed for interferometric measurement of the imaging quality of an imaging system (22). [13] Method according to claim 12, characterized byin that the first optical element (113) has a two-dimensional pattern structure (112) which extends at least partially along the contact surfaces of the optical elements, wherein the two-dimensional pattern structure (112) is designed for interferometric measurement of the imaging quality of the imaging system (22). [14] Method according to claim 12 or 13, characterized by that the second optical element (114) comprises or consists of a wavelength conversion material. [15] Use of an optical component (106) produced by a method according to one of claims 1 to 14 in an optical system (100) for interferometric measurement of the imaging quality of an imaging system (22).

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