Method for mounting optical system

Abstract

To provide an improved approach for assembling a lithography apparatus.SOLUTION: There is provided a method for mounting a lithography system comprising the steps of: a) measuring components K1-KN of an optical system in order to provide measurement data where N>1; b) virtualizing the components by means of the provided measurement data and generating an actual mounting model from the virtualized components, wherein the actual mounting model contains virtual actual positions (Pactual, Pactual_KN-1, Pactual_K2) of the virtualized components K1-KN in a virtually mounted state, c) determining a correction measure according to the actual mounting model and a target mounting model, wherein the target mounting model contains virtual target positions (Ptarget) of one or more of the virtualized components in the virtually mounted state, and d) mounting the components to form the optical system using the correction measure.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for assembling an optical system, a method for operating an optical system, a data processing apparatus, and a computer program product.

[0002] The entire content of German priority application No. 10 2019 218 925.3 is incorporated herein by reference. for use.

Background Art

[0003] Micro lithography is used, for example, in the manufacture of fine structure components such as integrated circuits. The micro lithography process is carried out using a lithography apparatus having an illumination system and a projection system. In this case, an image of a mask (reticle) illuminated by the illumination system is projected by the projection system onto a substrate, such as a silicon wafer, coated with a photosensitive layer (photoresist) and arranged in the image plane of the projection system, so as to transfer the mask structure to the photosensitive coating of the substrate. In the configuration of an optical system such as a projection system (also referred to as a projection lens or a projection optical box, POB), it is necessary to accurately position the optical surface and other functional surfaces (such as an aperture or an end stop) in all six degrees of freedom on the order of micrometers. In this case, it is often impossible to directly measure the position of the functional surface in the installed state.

[0004] Another problem arises because the required installation accuracy of the functional surface is significantly lower than the manufacturing accuracy of the component or individual parts, or a large amount of cost is required to manufacture the functional surface very accurately with respect to the contact surface and the reference surface. Therefore, adjustable spacers are provided between individual parts.

[0004]

[0005]

[0005] It is common to insert it into the boundary surface, for example, the contact surface or the screw connection part. The first installed If the spacer set does not lead to the required positional accuracy of the functional surface, this set is replaced with a new spacer set or adjusted individually, especially ground or polished. Generally, multiple adjustment loops occur due to the continuous adjustment of six degrees of freedom being adjusted. Further adjustment loops occur due to the situation where the effective directions of the spacers are not perpendicular to each other, that is, they are separated from each other . This increases the time required for manufacturing the optical system and thus also increases the cost. This is especially true when the spacers have to be adjusted individually, that is, manufactured to a predetermined dimension .

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0006] Based on the above, the object of the present invention is to provide an improved method.

MEANS FOR SOLVING THE PROBLEM

[0007] Therefore, a first aspect is a method for assembling an optical system, in particular a lithographic apparatus, comprising: a) measuring individual components K1 to KN of the optical system for the purpose of providing measurement data, where N > 1 ; and b) virtualizing the individual components K1 to KN using the provided measurement data and generating an actual assembly model from the virtualized individual components K1 to KN, the actual assembly model including the virtual actual positions of the virtualized individual components K1 to KN in the virtual assembly state ; and c) determining a correction measure based on the actual assembly model and a target assembly model, where the target assembly model is one or more virtual positions of the virtualized individual components K1 to KN in the virtual assembly state a step including a target position, d) forming an optical system by assembling individual parts K1 to KN using correction measures, and a method including the above is proposed.

[0008] As a result, the above-mentioned adjustment loop is generally avoided. Furthermore, correction can be performed at only one position or only a few positions, and the above correction results in a desired target position of one functional surface of (one of the individual parts K1 to KN). Therefore, it is not necessary to manufacture all individual parts very precisely. Furthermore, this also enables very precise adjustment of the relative positions of functional surfaces that are inaccessible by measurement means after assembly. In particular, as a result, this enables relaxation of the tolerances of the relevant components or individual parts and the assembly process, and thus it is possible to reduce development costs (e.g., development of precision tools) and manufacturing costs (lead time, defective products, individual part costs). It is possible.

[0009] The optical system can be a lithographic apparatus or a component thereof, such as an illumination system or a projection system.

[0010] The measurement according to step a) can in particular include measurement of the mechanical properties (in particular, dimensions, tolerances, etc. ) of each individual part, optical properties (reflectivity, etc.), and / or thermal properties. The measurement can in particular be carried out mechanically or optically.

[0011] In this case, "data" refers to electronic data.

[0012] "Virtualizing the individual parts K1 to KN" refers to the generation of data describing the individual parts K1 to K1. These data can describe the individual parts K1 to KN by points, surfaces, coordinate systems, or three-dimensional bodies.

[0013] ​​"Generating an actual assembly model" refers to adding additional data to the electronic data describing the individual parts K1 to KN. The additional data describes the relationships of the virtualized individual parts K1 to KN such that their virtual actual positions in the virtual assembly state are generated. These additional data can be configuration data derived from a CAD (computer-aided design) model. The CAD model can include geometric, mechanical, optical, and / or thermal

[0014] characteristics, parameters, and / or interfaces (between individual parts). As an example, the actual assembly model is generated by geometrically connecting

[0015] a plurality of virtualized individual parts K1 to KN. In an embodiment, the actual assembly model includes, for example, the mechanical relationships between the virtualized individual parts K1 to KN in addition to the

[0016] virtual actual positions of the virtualized individual parts K1 to KN. The target assembly model can include data derived from or derived from a CAD model. The target assembly model includes at least the (ideal or required) positions of one or more functional surfaces of one or more individual parts, but can also describe

[0017] the positions of other individual parts (without functional surfaces). As long as one or more actual and / or target positions of the virtualized individual parts K1 to KN are currently mentioned, this means the actual and / or target positions of one or more points, surfaces, and / or three-dimensional bodies (e.g.,

[0018] The determined corrective measures are preferably designed to act on the geometric and / or mechanical relationships between at least two of the individual parts K1 to KN. That is, the corrective measures affect, for example, the relative position and / or alignment of at least two individual parts. And / or mechanical relationship. For example, it affects the relative position and / or alignment of at least two individual parts.

[0019] The assembly includes, in particular, the connection, especially the joining, of the individual parts K1 to KN in meshing, press-fitting, and / or agglomeration. In this case, "connection" is to be understood as referring to meshing, press-fitting, or integral adhesive connection, or a combination thereof. A meshing connection is obtained by at least two mating partners engaging with each other in an interlocking or end-to-end manner. A press-fitting connection, for example a screw connection, presupposes a normal force on the mutually connected surfaces. A press-fitting connection can be obtained by frictional engagement. As long as the reaction force generated by static friction is not exceeded, the mutual displacement of the surfaces is prevented. A press-fitting connection can also exist as a magnetic force lock engagement. In an agglomeration connection, the mating partners are bonded to each other by atomic or molecular forces. An agglomeration connection is a non-detachable connection that can only be separated by the destruction of the connecting means. An agglomeration connection enables connection by, for example, adhesive bonding, soldering, welding, or vulcanization. Including the connection of the individual parts K1 to KN in meshing, press-fitting, and / or agglomeration, especially the joining. In this case, "connection" is understood to refer to meshing, press-fitting, or integral adhesive connection, or a combination thereof. A meshing connection is obtained by at least two mating partners engaging with each other in an interlocking or end-to-end manner. A press-fitting connection, such as a screw connection, presupposes a normal force on the mutually connected surfaces. A press-fitting connection can be obtained by frictional engagement. As long as the reaction force generated by static friction is not exceeded, the mutual displacement of the surfaces is prevented. A press-fitting connection can also exist as a magnetic force lock engagement. In an agglomeration connection, the mating partners are bonded to each other by atomic or molecular forces. An agglomeration connection is a non-detachable connection that can only be separated by the destruction of the connecting means.

[0020] N is an integer greater than 1.

[0021] According to one embodiment, the method includes The step of forming an actual assembly model by geometrically connecting the virtualized individual parts K1 to KN, And Based on the comparison between the virtual actual position of the virtualized individual part KN and the virtual target position of the virtualized individual part KN, The step of determining the corrective measures in step c). Including.

[0022] This represents what is known as virtual contact assembly. According to the deformation mode of the virtual contact assembly when all individual parts are installed according to their geometric measurement data, the location where the functional surfaces are arranged is required. For example, it is also possible to include a margin considering the deformation of individual parts . The deformation can result from different mounts and different masses of individual parts or assemblies . As an example, when constructing a projection lens, the force frame is first attached, and then modules are sequentially loaded onto it, so the force frame deforms under the change of load.

[0023] According to yet another embodiment, the method includes fixing the virtualized individual parts K1 to KN at their target positions from the target assembly model, thereby generating an actual assembly model, and geometrically connecting the virtualized individual parts K2 to KN - 1 with K1 and / or KN, and determining a corrective measure in step c) based on the virtual actual positions of at least two virtualized individual parts K2 to KN - 1, and including.

[0024] This represents virtual target point assembly. Within the scope of virtual target point assembly, directly, that is, between (among the individual parts K2 to KN) the (two or more) individual parts that do not come into contact at the end of the connection process, it is preferable that the remaining gap occurs.

[0025] According to yet another embodiment, the corrective measure in step d) is applied to the individual part KN - 1, or to the region between the individual parts KN - 1 and KN, particularly the gap.

[0026] Advantageously, the correction is carried out adjacent to the individual component KN (in particular having a functional surface). There is a high probability that the tolerances are mutually compensated up to the individual component KN-1.

[0027] According to yet another embodiment, the individual component KN comprises an optical element, in particular a mirror, a lens element, an optical grating, and / or a waveplate, a diaphragm, a sensor, and / or an end stop.

[0028] These show examples of individual components KN having a functional surface.

[0029] Alternatively, the individual component KN can be a mechanical component, a mechatronics component, in particular an actuator, and / or a bearing.

[0030] According to yet another embodiment, the individual component KN-1 comprises a mechanical component, mechatronics components, in particular an actuator, and / or a bearing.

[0031] Advantageously, defect correction can be easily carried out, for example, by adjusting the operating range of an actuator, so that the defect correction is carried out on the above components. In this case, the "mechanical component" includes, in particular, a mechanical reference surface or fit, such as an alignment pin or alignment hole. In this case, the "bearing" includes, in particular, a mechanical bearing and / or a magnetic bearing, such as a weight compensation device for an optical element.

[0032] According to yet another embodiment, the correction measures include, in particular, inserting a spacer between two of the individual components K1 to KN, adjusting the play of the fixing means that particularly fix two of the individual components K1 to KN to each other, and / or adjusting the operating point of an actuator as a constituent part of a mechatronics component, particularly of one of the individual components K1 to KN. ​​​​​

[0033] According to yet another embodiment, the corrective measure in step c) is determined based on the possible actuator movement amount.

[0034] According to yet another embodiment, N>5 or 10.

[0035] According to yet another embodiment, in step c), the gap between two of the individual parts K1 to KN is determined, and in step d), a spacer is inserted into the gap.

[0036] The spacer is preferably a spacer means, a shim, etc. made of metal or ceramic in particular. As an alternative or in addition, the spacer can be adjustable with respect to the space defined thereby, in particular with respect to its thickness, and can be provided, for example, in the form of a setting screw or mutually displaceable wedges. In an embodiment, the spacer can be removed again after assembly, i.e., in particular after step d).

[0037] According to yet another embodiment, the corrective measure according to step c) relates to at least the first and second degrees of freedom.

[0038] According to yet another embodiment, in step d), the corrective measure is applied to the first part of the individual parts K1 to KN or between the first pair of the individual parts K1 to KN with respect to the first degree of freedom, and to the second part of the individual parts K1 to KN or between the second pair of the individual parts K1 to KN with respect to the second degree of freedom.

[0039] As a result of the corrective measure being divided between different individual parts, this can be determined more easily (the avoidance or reduction of the mutual influence of the corrective measures is avoided). ​

[0040] According to yet another embodiment, the method comprises measuring the assembled optical system to provide assembly measurement data, and determining yet another correction measure based on a comparison between the assembly measurement data and a target assembly model, and positioning one or more of the individual parts K1 - KN based on the determined yet another correction measure. This includes.

[0041] At this point, further correction is made by comparing the assembled optical system with the target assembly model.

[0042] According to yet another embodiment, the actual assembly model is determined using analytical geometry, in particular homogeneous coordinates and / or Euler angles.

[0043] This can be easily implemented, in particular, by a computer device such as a microprocessor.

[0044] A second aspect is a method of operating an optical system, in particular a lithographic apparatus, comprising a) measuring the individual parts K1 - KN of the optical system to provide measurement data, where N > 1, and b) virtualizing the individual parts K1 - KN using the provided measurement data and generating an actual assembly model from the virtualized individual parts K1 - KN, the actual assembly model including the virtual actual positions of the virtualized individual parts K1 - KN in a virtual assembled state, and c) determining a correction measure based on the actual assembly model and a target assembly model, the target assembly model including one or more virtual target positions of the virtualized individual parts K1 - KN in a virtual assembled state. ​​​​​d) Using correction measures, assemble the individual components K1 to KN to form an optical system and operate the optical system and propose a method including this.

[0045] Operating the optical system refers to its use for its intended purpose. In particular, operating the optical system means performing an exposure process using the optical system, for example, exposing a wafer for manufacturing a microchip. Advantageously, by using appropriate adjustment of the controller of the optical system in particular, manufacturing defects (tolerances) are corrected here. As an example, a movement or operating point of an actuator during operation can be given so that correction is obtained.

[0046] The method according to the second aspect can be combined with the method according to the first aspect, so that correction measures are first determined during assembly and during operation, and then applied during assembly or during operation. Therefore, according to the third aspect, the following is provided.

[0047] A method of assembling and / or operating an optical system, in particular a lithographic apparatus, comprising a) measuring the individual components K1 to KN of the optical system for the purpose of providing measurement data where N>1, b) virtualizing the individual components K1 to KN using the provided measurement data and generating an actual assembly model from the virtualized individual components K1 to KN, the actual assembly model including the virtual actual positions of the virtualized individual components K1 to KN in the virtual assembly state c) determining correction measures based on the actual assembly model and a target assembly model the target assembly model including one or more virtual target positions of the virtualized individual components K1 to KN in the virtual assembly state ​​​​​d) forming an optical system by assembling K1 to KN individual components using correction measures, and / or operating the optical system using correction measures, and a method comprising the steps of.

[0048] A fourth aspect is a data processing apparatus, virtualizing individual components K1 to KN of an optical system using provided measurement data, and generating an actual assembly model from the virtualized individual components K1 to KN, the actual assembly model including virtual actual positions of the virtualized individual components K1 to KN in a virtual assembly state, and a virtualization unit determining correction measures to be applied during the assembly of the optical system from the individual components K1 to KN or during the operation of the optical system assembled from the individual components K1 to KN based on the actual assembly model and a target assembly model, the target assembly model including one or more virtual target positions of the virtualized individual components K1 to KN, and a determination unit proposing a data processing apparatus including the determination unit.

[0049] Each device or unit, such as a measurement device, a computer device, a virtualization unit, or a determination unit, can be implemented either in hardware and / or in software. In the case of a hardware implementation, each unit can be embodied as a device or part of a device, for example, as a computer or a microprocessor. In the case of a software implementation, each device or unit can be embodied as a computer program product, as a function, as a routine, as part of program code, or as an executable object.

[0050] ​​​​​​​​The fifth aspect is a computer program product, which is at least one program control device, using the provided measurement data to virtualize the individual components K1 to KN of the optical system, and generating an actual assembly model from the virtualized individual components K1 to KN, where the actual assembly model includes the virtual actual positions of the virtualized individual components K1 to KN in the virtual assembly state, and based on the actual assembly model and the target assembly model, determining the corrective measures to be applied during the assembly of the optical system from the individual components K1 to KN or during the operation of the optical system assembled from the individual components K1 to KN, where the target assembly model includes one or more virtual target positions of the virtualized individual components K1 to K N in the virtual assembly state, and proposing a computer program product that instructs the implementation.

[0051] For example, a computer program product such as computer program means can be provided or supplied, for example, in the form of a storage medium, such as a memory card, USB stick, CD-ROM, DVD, etc., or in the form of a file downloadable from a server on a network. It can be done, for example, by transferring an appropriate file having the computer program product in a wireless communication network. In this case, "one" should not necessarily be understood as limiting to exactly one element.

[0052] Rather, for example, two, three, or more elements can be provided. Here, any other numbers used should not be understood to mean that they are limited to the exact number of elements described. Rather, unless otherwise indicated, numerical deviations above and below are possible. a), ​b) etc. The notation of method steps should not be construed as a limitation to a specific order. Step can also be rephrased, especially for the purpose of inserting a previous or subsequent step or an intermediate step For example, step b) becomes step f).

[0053] The embodiments and features described for the method according to the first aspect are applicable mutatis mutandis to the method according to the second and third aspects, and vice versa.

[0054] Further possible embodiments of the present invention also include any combination of features or embodiments that are not explicitly mentioned above or below with respect to the exemplary embodiments. In this case, a person skilled in the art may add individual aspects to each basic form of the present invention as improvements or supplements.

[0055] Further advantageous improvements and aspects of the present invention are the subject matter of the dependent claims and also the subject matter of the exemplary embodiments of the present invention described below. In the following text, the present invention will be described in more detail based on the preferred embodiments with reference to the accompanying drawings. [Brief Description of the Drawings]

[0056]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0057] Unless otherwise indicated, the same or functionally identical elements are denoted by the same reference numerals in the figures. Note that the drawings are not necessarily to scale.

[0058] FIG. 1A shows a schematic diagram of an EUV lithography apparatus 100A including a beam shaping / illuminating system 102 and a projection system 104. In this case, EUV means "extreme ultraviolet", and indicates a wavelength of the used light of 0.1 nm to 30 nm. The beam shaping / illuminating system 102 and the projection system 104 are each provided in a vacuum housing (not shown), and each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housing is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. The EUV lithography apparatus 100A has an EUV light source 106A. A plasma source (or synchrotron) that emits radiation 108A in the EUV region (extreme ultraviolet region), that is, for example, in a wavelength range of 5 nm to 20 nm, can be provided as the EUV light source 106A. In the beam shaping / illuminating system 102, the EUV radiation 108A is focused and the desired operating wavelength is filtered from the EUV radiation 108A. Since the EUV radiation 108A generated by the EUV light source 106A has a relatively low transmittance in air, the beam shaping / illuminating system 1 is provided in a vacuum housing (not shown), and each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housing is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. is provided in a vacuum housing (not shown), and each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housing is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. can also be provided in the machine room.

[0059] The EUV lithography apparatus 100A has an EUV light source 106A. A plasma source (or synchrotron) that emits radiation 108A in the EUV region (extreme ultraviolet region), that is, for example, in a wavelength range of 5 nm to 20 nm, can be provided as the EUV light source 106A. In the beam shaping / illuminating system 102, the EUV radiation 108A is focused and the desired operating wavelength is filtered from the EUV radiation 108A. Since the EUV radiation 108A generated by the EUV light source 106A has a relatively low transmittance in air, the beam shaping / illuminating system 1 is provided in a vacuum housing (not shown), and each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housing is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. In the beam shaping / illuminating system 102, the EUV radiation 108A is focused and the desired operating wavelength is filtered from the EUV radiation 108A. The EUV radiation 108A generated by the EUV light source 106A has a relatively low transmittance in air, so the beam shaping / illuminating system 1 is provided in a vacuum housing (not shown), and each vacuum housing is evacuated using an evacuation device (not shown). The vacuum housing is surrounded by a machine room (not shown) provided with a driving device for mechanical movement or setting of the optical element. Further, an electric controller or the like may also be provided in the machine room. The beam guiding spaces in 02 and the projection system 104 are evacuated.

[0060] The beam shaping and illumination system 102 shown in FIG. 1A includes five mirrors 110, 112, 114, 1 16, 118. After passing through the beam shaping and illumination system 102, the EUV radiation 108A is directed to the photomask (reticle) 120. The photomask 120 is also in the form of a reflective optical element and can be arranged outside the systems 102, 104. Further, the EUV radiation 108 A can be directed to the photomask 120 by the mirror 122. The photomask 120 has a structure that is reduced by the projection system 104 and imaged onto the wafer 124 or the like. The projection system 104 (also referred to as a projection lens) has six mirrors M1 to M6 for imaging the photomask 120 onto the wafer 124. In this case, the individual mirrors

[0061] M1 to M6 of the projection system 104 can be arranged symmetrically with respect to the optical axis 126 of the projection system 104. It should be noted that the number of mirrors M1 to M6 of the EUV lithography apparatus 100A is not limited to the number shown in the figure. More or fewer mirrors M1 to M6 can be provided. Further, the mirrors M1 to M6 are generally curved on the front side for beam shaping.

[0062] FIG. 1B shows a schematic view of a DUV lithography apparatus 100B including a beam shaping and illumination system 102 and a projection system 104. In this case, DUV means "deep ultraviolet" and indicates the wavelength of the used light of 30 nm to 25 0 nm. As already described with reference to FIG. 1A, the beam shaping and illumination system 102 and the projection system 104 can each be provided in a vacuum housing and / or surrounded by a machine room having corresponding drive devices.

[0063] The DUV lithography apparatus 100B has a DUV light source 106B. As an example, for instance an ArF excimer laser that emits radiation 108B in the DUV range of 193 nm can be provided as the DUV light source 1 06B.

[0064] The beam shaping and illumination system 102 shown in FIG. 1B guides the DUV radiation 108B to the photomask 12 0. The photomask 120 is formed as a transmissive optical element and can be arranged outside the systems 102, 104 . The photomask 120 has a structure that is reduced by the projection system 104 and imaged onto the wafer 1 24 and the like.

[0065] The projection system 104 has a plurality of lens elements 128 and / or mirrors 130 for imaging the photomask 120 onto the wafer 124. In this case, the individual lens elements 128 and / or mirrors 130 of the projection system 104 can be arranged symmetrically with respect to the optical axis 126 of the projection system 104 . Note that the number of lens elements 128 and mirrors 130 of the DUV lithography apparatus 100B is not limited to the number shown in the figure . A larger or smaller number of lens elements 128 and / or mirrors 130 can also be provided. Furthermore, the mirror 130 is generally curved on the front side for beam shaping.

[0066] The air gap between the lens element 128 and the wafer 124 can be replaced with a liquid medium 132 having a refractive index greater than 1 . The liquid medium 132 can be, for example, high-purity water . Such a structure is also referred to as immersion lithography and has high photolithography resolution . The medium 132 can also be referred to as the immersion liquid.

[0067] Figure 2 shows a data processing device 200 used in a method of assembling and operating a projection system or a projection lens 104 (specifically shown in FIGS. 1A or 1B) or any other optical system. The flowchart of this method is shown in FIG. 7.

[0068] The data processing device 200 is, for example, in the form of a computer device including a microprocessor and associated memory means, such as RAM, ROM, etc. The data processing device 200 comprises a virtualization unit 202 and a determination unit 204. The units 202, 204 can be implemented hardware-wise and / or software-wise, i.e., in the form of program code.

[0069] Mechanical measurement data MEM and any optical measurement data OEM are provided to the virtualization unit 202. Furthermore, additional measurement data, such as thermal measurement data, can also be provided to the virtualization unit 202.

[0070] The mechanical measurement data describes at least the geometric shape of each individual part K1 - KN. The individual parts K1 - KN are exemplarily shown in FIG. 2 in a state where they are not yet assembled, and are assembled to form the projection lens 104 (see FIGS. 1A, 1B, FIGS. 3, and 4) in the assembly steps described in more detail below. The individual parts K1 - KN can be individual parts or assemblies (consisting of a plurality of interconnected individual parts).

[0071] The optical measurement data OEM describes one or more optical characteristics of the individual parts K1 - KN. Here, by way of example, the following are mentioned: the relative position of the optical axis or optical surfaces, the reflectivity (optionally spatially resolved), the transmittance (likewise optionally spatially resolved).

[0072] The mechanical measurement data MEM may be provided, in particular, by a measurement device 206, such as a coordinate measuring machine (CMM) (S700 in FIG. 7), and the measurement device 206 mechanically measures the individual parts K1 to KN for this purpose (in practice). The optical measurement data OEM M may likewise be provided by a measurement device 208, such as an interferometer (step S702), and the measurement device 208 optically measures the individual parts K1 to KN (in practice). The virtualization unit 202 generates virtual individual parts K1 to KN from the provided measurement data MEM, OEM (S704 in FIG. 7). This is to be understood as a mathematical, in particular geometric, description of the (real) individual parts K1 to KN, for example in the form of a matrix, which is stored in the data memory. Furthermore, configuration data ABD is provided to the virtualization unit 202. The configuration data ABD describes at least geometric and possibly mechanical connections, interfaces, and contact surfaces between the virtual individual parts K1 to KN in a virtual actual assembly model IMM that has not yet been created. In this case, the geometric connection or geometric interface reproduces the real connection or interface, for example the fixing means between the individual parts K1 to KN to be assembled. The configuration data ABD can be provided from a CAD (computer-aided design) program and / or an optical design program (S706 in FIG. 7). As an example, this software can be executed on a computer device 210.

[0073]

[0074]

[0075]

[0076] ​​​​​​​​​​​​The virtualization unit 202 generates a (virtual) actual assembly model IMM from the virtualized individual parts K1 to KN and the configuration data ABD (step S708 in FIG. 7). The individual parts K1 to KN are virtually assembled with each other in the actual assembly model IMM, and the relationship between the individual parts K1 to KN, particularly the geometric arrangement, is defined by the configuration data ABD, particularly the contact surface and boundary surface information described therein. KN are virtually assembled with each other in the actual assembly model IMM, and the relationship between the individual parts K1 to KN, particularly the geometric arrangement, is defined by the configuration data ABD, particularly the contact surface and boundary surface information described therein. KN are virtually assembled with each other in the actual assembly model IMM, and the relationship between the individual parts K1 to KN, particularly the geometric arrangement, is defined by the configuration data ABD, particularly the contact surface and boundary surface information described therein. KN are virtually assembled with each other in the actual assembly model IMM, and the relationship between the individual parts K1 to KN, particularly the geometric arrangement, is defined by the configuration data ABD, particularly the contact surface and boundary surface information described therein.

[0077] The actual assembly model IMM can be generated in various ways, and subsequently the determined correction measure KOM is adapted to the corresponding model. In principle, the correction measure KOM is determined from the actual assembly model IMM and the target assembly model SMM, particularly by comparing the two models IMM and SMM. The actual assembly model IMM can be generated in various ways, and subsequently the determined correction measure KOM is adapted to the corresponding model. In principle, the correction measure KOM is determined from the actual assembly model IMM and the target assembly model SMM, particularly by comparing the two models IMM and SMM. The actual assembly model IMM can be generated in various ways, and subsequently the determined correction measure KOM is adapted to the corresponding model. In principle, the correction measure KOM is determined from the actual assembly model IMM and the target assembly model SMM, particularly by comparing the two models IMM and SMM. The actual assembly model IMM can be generated in various ways, and subsequently the determined correction measure KOM is adapted to the corresponding model. In principle, the correction measure KOM is determined from the actual assembly model IMM and the target assembly model SMM, particularly by comparing the two models IMM and SMM.

[0078] The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models. The target assembly model SMM describes one or more virtual target positions of the virtualized individual parts K1 to KN in the virtual assembly state. In this case, the target assembly model SMM assumes ideal individual parts K1 to KN, that is, individual parts K1 to KN that exactly correspond to, for example, CAD models.

[0079] First, the contact assembly model will be described below with reference to FIG. 3, and then the target point assembly model will be described with reference to FIG. 4.

[0080] According to the contact assembly model, the virtualized individual parts K1 to KN are, in an exemplary embodiment, stacked on top of each other and geometrically connected. In this case, for example, a base 300 is selected for the individual part K1. The subsequent individual parts K2 to KN are stacked on top of each other while considering the configuration data ABD, that is, K2 is placed on K1, K3 is placed on K2, and KN is placed on KN- 1.

[0081] As an example, the individual part KN is selected to be a component having what is known as a functional surface. This means a surface important for the function of the lithographic apparatus, such as an optical surface or an end stop, that is, a stop that limits the maximum movement of the optical element. Therefore, the individual part KN is, in particular, an optical element, such as a mirror, a lens element, an optical grating, or a wave plate or the like. In an exemplary embodiment, the individual part KN is a mirror having an optically effective surface 302 (light footprint print).

[0082] Here, by stacking the individual parts K1 to KN on top of each other, the individual part KN or its function al surface (optically effective surface 302) is arranged at the actual position P actual In FIG. 3, the individual part KN is shown at this position using a dashed line The determination unit 204 (see FIG. 2) compares the actual position P

[0083] with the target position P actual from the target assembly model SMM FIG. 3 shows the target position P target of the individual part KN using a solid line position P targetis shown. In this case, P actual and P target there is a deviation in the form of an offset or a gap V in the x direction (i.e., in the plane of the main extension plane of the optically effective surface 302, for example) and in the z direction, for example the vertical direction, i.e., a direction particularly perpendicular to the main extension plane of the optically effective surface 302. Therefore, as a corrective measure, in step S710 (FIG. 7), the determination unit 204 determines the insertion of one or more spacers 304, which can be in the form of spacer means, shims, etc., made of metal and / or ceramic in particular. The spacer 304 is preferably inserted between the individual part KN and the individual part KN-1 below it. In this case, N is preferably 6 or more and less than 10. Further alternatively, the corrective measure can be carried out on the individual part KN itself, for example by appropriate material ablation therefrom. More preferably, the individual part KN-1 is a mechatronics component, in particular an actuator, and / or a bearing. In particular, the actuator is advantageous because it can be set to provide a corrective measure. As an example, in the case of the exemplary embodiment of FIG. 3, the actuator KN-1 can be set with respect to its operating range or operating point so as to compensate for the offset or gap V. However, the (maximum) possible actuator movement of the actuator should be considered at that time. Therefore, in this case (when the actuator movement is insufficient), the spacer 304 is not necessary (although this will probably be an exception). Rather, the actuator KN-1 is during the operation of the lithographic apparatus (100A, 100B) (FIG. 7

[0084]

[0085] In this case, as shown by the dashed connecting lines in FIG. Steps S712 and S714 are optionally omitted, and the projection lens 104 is assembled without applying corrective measures. It is seen as important.

[0086] By way of example, the same applies to the bearing KN-1. By way of example, the bearing comprises a screw means With this, the adjustment can be easily performed. , a corresponding procedure can be implemented. For example, to compensate for an offset or gap V Alternatively, a sensor can be used to monitor or verify corrective measures. This can be done.

[0087] The corrective measures determined above can be optionally verified in the virtual actual assembly model IMM. For this purpose, the actual assembly model IMM is regenerated applying the determined corrective measures. Step S710 is repeated.

[0088] Then, applying the determined corrective measures, the projection lens 104 is divided into individual parts K1 to KN. In particular, the corrective measures are taken during the assembly of the projection lens 104. That is, the spacer 304 is manufactured and is fixed to the gear when assembling the individual components K1 to KN. Alternatively or additionally, they can be inserted into the actuator, for example. As described above for the lithography apparatus 10, the lithography apparatus 10 may include a projection lens 104. 0A, 100B during operation. In optional step S714, The projection lens 104 is actually measured, and the obtained assembly measurement data is used for further correction measures. This is particularly useful for determining the position of the assembly, e.g. the insertion of spacers. It can be implemented by comparison with the model SMM.

[0089] Furthermore, FIG. 3 shows that each or all of the individual parts K1 to KN can be in the form of an assembly. As an example, the individual parts K1 and K2 each include a force frame 306, for example, one or more optical elements 308, such as mirror or lens elements, are fixed thereto.

[0090] The above target point assembly model will be described below with reference to FIG. 4. Here, the virtual individual parts K1 to KN are fixed to their target positions P from the target assembly model SMM. target Subsequently, individual parts K2, K3 (not shown), etc. are stacked on top of individual part K1, and individual parts KN-X,..., KN-1 (not shown) are stacked under individual part KN. In this case, X is a number required by the design. Thus, in an exemplary embodiment, the actual position P of individual part KN-1 actual_KN-1 (shown by a dashed line in FIG. 4) and the actual position P of individual part K2 actual_K2 occur. The determination unit 204 then determines the offset or gap V between the actual positions P a ctual_KN-1 and P actual_K2 , and determines the insertion of a spacer 304 between individual parts KN and KN- 1 as a correction measure so that the offset or gap V is eliminated and individual parts KN-1 and K2 are arranged relative to each other in the arrangement defined by the configuration data ABD. The new position of the resulting individual part KN-1 is shown by a solid line in FIG. 4.

[0091] Otherwise, the features shown in FIG. 3 apply mutatis mutandis to FIG. 4.

[0092] In the exemplary embodiment shown in FIGS. 3 and 4, the corrective action is performed in two degrees of freedom, specifically parallel It only concerns the X and Z directions. Naturally, the correction measures have 6 degrees of freedom (3 rotational and 3 translational). It is possible to concern each of these degrees of freedom simultaneously.

[0093] FIG. 5 illustrates, for example, how each offset or gap V is corrected in the x, y, and z directions. The insertion of spacers 304 for the purpose of forming a spacer 304 is shown. In this case, three spaces in one individual part KN-1 are inserted. The corrective measures for the correction in the vertical direction are shown on the left. In contrast, the corrective measures shown on the right and with respect to the spatial directions x, z such that at least two distinct individual parts, in particular Actuator KN-1' (x direction) and actuator KN-1' to support KN-3' After the assembly of the spacer 304, The optical element KN and the actuators KN-1 and KN-1' are assembled to form a projection lens 10. 4. Then, the optical surface 302 moves to its desired target position P target Located in.

[0094] As shown below in FIG. 6, the above mentioned actual assembly model IMM is based on homogeneous coordinates and / or Euler coordinates. - It can be found using the angle.

[0095] Components K1, K2 (corresponding to KN-1), and K3 (corresponding to KN-1) are manufactured Due to tolerances, the robot is positioned away from each target position (hereinafter also referred to as "design" or "target attitude"). can be.

[0096] Therefore, the question is whether the functional surface CS_F_actual is The target position CS_F_target is reached, i.e., more accurately than the sum of the manufacturing tolerances, usually To be more accurate than any individual manufacturing tolerances of the intention, it is to determine the thickness that the positioning elements Sp1, Sp2, and Sp3 (especially corresponding to the spacer 304) should have.

[0097] The coordinate system CS_K represents (virtualizes) the body K, and is defined by CS.orig = origin, CS.ex = X axis, CS.ey = Y axis, and CS.ez = Z axis, and (CS_K)^B refers to the coordinates of CS_K in CS _B.

[0098] The following calculation example shows this.

[0099] The target position given by CS_B: (CS_F_target)^B = [95, 200, 305] mm, Ry = -14° CS_F_target = name:'CS_F' base: 'CS_Base' orig: [95 200 305] ex: [ 0.9703 0 0.2419] ey:

[0010] ez: [-0.2419 0 0.9703]

[0100] The three spacer reference points and effective directions: Sp1 = name: 'Spc1' Sp2 = name: 'Spc2' Sp3 = name: 'Spc3' base: 'CS_Base' base: 'CS_Base' base: 'CS_Base' orig: [150 300 190] orig: [340 300 250] orig: [410 300 320] ez: [-1 0 2] / sqrt(5) ez: [-1 0 2] / sqrt(5) ez: [-1 0 0]

[0101] When measuring CS_K3 with CS_B: (CS_K3_actual)^B = [103 210 167], Ry = -17°, Rz = 182° CS_K3_actual = name: 'CS_K3' base: 'CS_Base' orig: [103 210 167] ex: [-0.9557 -0.0298 -0.2928] ey: [ 0.0334 -0.9994 -0.0072] ez: [-0.2924 -0.0167 0.9562]

[0102] When measuring CS_F with CS_K3_actual: (CS_F_actual)^K3 = [-25 0 126]mm, Ry = -5°, R z = 179° CS_F_actual_K3 = name: 'CS_F' base: 'CS_K3' orig: [-25 0 126] ex: [-0.9960 0.0175 -0.0871] ey: [-0.0174 -0.9998 -0.0015] ez: [-0.0872 0 0.9962]

[0103] For example, calculation of the actual pose or actual position of CS_F in CS_B by coordinate transformation from CS_K3 to CS_B in homogeneous coordinates: Calculation of the actual pose or actual position of CS_F: (CS_F_actual)^B = K3_2_B * (CS_F_actual)^K3 JPEG2025094081000002.jpg31127 Using the 4x4 transformation matrix K3_2_B CS_F_achtual = name: 'CS_F' base: 'CS_Base' orig: [90.0542 208.6420 294.7950] ex: [ 0.9780 0.0137 0.2082] ey: [-0.0163 0.9998 0.0109] ez: [-0.2080 -0.0140 0.9780]

[0104] CS_F coordinates (IS_abs) and CS_F target coordinates (IS_rel) of CS_F_ Offset from CS_F_actual to target, and evaluation of actual pose or actual position (compared with specification Tol_rel) Pose CS_F wrt CS_Base: [mm,mrad] Tx Ty Tz Rx Ry Rz Target: 95.000 200.000 305.000 -0.000 -244.346 -0.000 Actual: 90.054 208.642 294.795 14.344 -209.491 16.674 I-S_abs: -4.946 8.642 -10.205 14.344 34.855 16.674 I-S_rel: -7.268 8.642 -8.705 14.039 34.830 13.202 Tol_rel: 2.000 2.000 1.000 5.000 5.000 2.000

[0105] Calculation of actuator movement amount at CS_B, where Sp.ez is the unit vector in the effective direction of the positioning element (for example, the effective direction is the thickness that brings about the displacement of K3 towards the target position) Sp.orig is the target position of K3 at the reference point (the K3 side support base of the positioning element) and sp_actual is the actual position of K3 at the reference point: sp_delta = dot(sp_is, Sp.ez) where sp_is = sp.orig - sp_actual = Spacer point displacement from actual to target Change [mm] Sp1 5.04 Sp2 11.83 Sp3 -6.29

[0106] The present invention has been described based on exemplary embodiments, but can be modified in various ways. possible.

Explanation of Signs

[0107] 100A EUV lithography apparatus 100B DUV lithography apparatus 104 Beam shaping and illumination system 104 Projection system 106A EUV light source 106B DUV light source 108A EUV radiation 108B DUV radiation 110 Mirror 112 Mirror 114 Mirror 116 Mirror 118 Mirror 120 Photomask 122 Mirror 124 Wafer 126 Optical axis 128 Lens element 130 Mirror 132 Medium 200 Data processing device 202 Virtualization unit 204 Decision unit 206 Measuring device 208 Measuring device 210 Computer device 212 CNC milling device 300 Base 302 Optical effective surface 304 Spacer 306 Force frame 308 Optical element ABD Configuration data IMM Actual assembly model KOM Correction measures K1~KN Individual parts P target Target position P actual Actual position P actual_KN-1 Actual position P actual_K2 Actual position MEM Mechanical measurement data M1 Mirror M2 Mirror M3 Mirror M4 Mirror M5 Mirror M6 Mirror OEM Optical measurement data SMM Target assembly model S700~S716 Method steps V Gap

Claims

1. Method for assembling an optical system (104), in particular a lithographic apparatus (100A, 100B) There was, a) individual components of said optical system (104) for the purpose of providing measurement data (MEM, OEM) Steps (S700, S702) of measuring K1 to KN, where N>1; 、 b) Using the provided measurement data (MEM, OEM), The individual parts K1 to KN are virtualized (S704) and geometrically connected to each other. By this, an actual assembly model (IMM) is generated from the virtualized individual parts K1 to KN. The actual assembly model (IMM) is a model of a virtual assembly state (S708). The virtual actual positions (P ａｃｔｕａｌ , P ａｃｔｕａｌ＿ ＫＮ－１ , P ａｃｔｕａｌ＿Ｋ２ ) c) Taking corrective measures based on the actual assembly model (IMM) and the target assembly model (SMM) The step of determining (S710) is that the target assembly model (SMM) is a virtual assembly state. One or more virtual target positions (P ｔａｒｇｅｔ ) and d) Assembling the individual components K1 to KN using the corrective measures to form the optical system (104) and forming (S712) The method includes:

2. 10. The method of claim 1 , The virtual individual parts K1 to KN are geometrically connected to form the actual assembly model. generating a model (IMM); The virtual actual position (P ａｃｔｕａｌ ) and the virtualized The virtual target position (P ｔａｒｇｅｔ Based on the comparison with determining said corrective action in The method further comprising:

3. 10. The method of claim 1 , The virtualized individual parts K1 to KN are then processed by the target assembly model (SMM) Target position (P ｔａｒｇｅｔ ) to generate the actual assembly model (IMM). and The virtualized individual parts K2 to KN-1 are geometrically connected to K1 and / or KN. Steps and The virtual actual positions (P ａｃｔ ｕａｌ＿ＫＮ－１ , P ａｃｔｕａｌ＿Ｋ２ Based on the above, in step c), the corrective measures are determining a position of the The method further comprising:

4. The method according to any one of claims 1 to 3, wherein the complement in step d) is The corrective action is to apply to the individual part KN-1 or to the area between the individual parts KN-1 and KN, in particular The method is applied to the gap (V).

5. The method according to any one of claims 1 to 4, The individual components KN may be optical elements, in particular mirrors, lens elements, optical gratings and / or wavelengths. and / or including plates, apertures, sensors, and / or end stops; The individual parts KN-1 are mechanical components, mechatronic components, in particular The method includes an actuator and / or a bearing.

6. The method according to any one of claims 1 to 5, wherein the corrective measures are carried out in particular by adjusting the individual components. Inserting a spacer (304) between two of the individual components K1 to KN; Adjustment of the play of the fastening means which fasten the two together, in particular to each other, and / or mechatronic control. an actuator as a component, in particular as a part of one of the individual parts K1 to KN; The method includes adjusting an operating point of the

7. 7. The method according to claim 5 or 6, wherein the corrective action in step C) is The method is determined based on a possible actuator travel of the actuator.

8. The method of any one of claims 1 to 7, wherein N>5 or 10.

9. The method according to any one of claims 1 to 8, wherein in step c) The gap (V) between two of the individual components K1 to KN is determined and in step d) , a spacer is inserted into said gap.

10. The method according to any one of claims 1 to 9, wherein the correction according to step c) The measure is a method relating to at least a first and a second degree of freedom (x, y, x).

11. 11. The method of claim 10, wherein the corrective action is taken in step d) by: Regarding the first degree of freedom (x), the first component of the individual components K1 to KN or the individual component K1 〜KN, and for the second degree of freedom (z), The method is applied to the product or between a second pair of said individual components K1 to KN.

12. The method according to any one of claims 1 to 11, A step of measuring the assembled optical system (104) to provide assembly measurement data. (S714) and Further corrections are made based on a comparison of the assembly measurement data and the target assembly model (SMM). determining a corrective action; Based on the determined further corrective measures, one or more of the individual components K1 to KN are and aligning the The method further comprising:

13. A method for operating an optical system (104), in particular a lithographic apparatus (100A, 100B), So, a) individual components of said optical system (104) for the purpose of providing measurement data (MEM, OEM) Steps (S700, S702) of measuring K1 to KN, where N>1; 、 b) Using the provided measurement data (MEM, OEM), The individual parts K1 to KN are virtualized (S704) and geometrically connected to each other. By this, an actual assembly model (IMM) is generated from the virtualized individual parts K1 to KN. The actual assembly model (IMM) is a model of a virtual assembly state (S708). The virtual actual positions (P ａｃｔｕａｌ , P ａｃｔｕａｌ＿ ＫＮ－１ , P ａｃｔｕａｌ＿Ｋ２ ) c) Taking corrective measures based on the actual assembly model (IMM) and the target assembly model (SMM) The step of determining (S710) is that the target assembly model (SMM) is a virtual assembly state. One or more virtual target positions (P ｔａｒｇｅｔ ) and d) Assembling the individual components K1 to KN using the corrective measures to form the optical system (104) and operating the optical system (104). The method includes:

14. A data processing device (200), Using the provided measurement data (MEM, OEM), the individual components K1 to K5 of the optical system (104) KN is virtualized, and an actual assembly model (IMM) is created from the virtualized individual parts K1 to KN. The actual assembly model (IMM) is a virtual assembly state. The virtual actual positions (P ａｃｔｕａｌ , P ａｃｔｕ ａｌ＿ＫＮ－１ , P ａｃｔｕａｌ＿Ｋ２ A virtualization unit (202) including Based on the actual assembly model (IMM) and the target assembly model (SMM), During assembly of the optical system (104) from K1 to KN or during assembly from the individual parts K1 to KN A decision unit (104) for determining corrective measures to be applied during operation of the optical system (104) installed. 204), and the target assembly model (SMM) is the virtual individual One or more virtual target positions (P ｔａｒｇｅｔ ) including the decision unit ( 204) and A data processing device comprising:

15. A computer program product for executing at least one program-controlled device 、 Using the provided measurement data (MEM, OEM), the individual components K1 to K5 of the optical system (104) KN is virtualized (S704), and an actual assembly model is created from the virtualized individual parts K1 to KN. (IMM), and the actual assembly model (IMM) is a virtual assembly state. The virtual actual positions (P ａｃｔｕａｌ , P ａｃｔｕａｌ ＿ＫＮ－１ , P ａｃｔｕａｌ＿Ｋ２ ) Based on the actual assembly model (IMM) and the target assembly model (SMM), During assembly of the optical system (104) from K1 to KN or during assembly from the individual parts K1 to KN A step (S7) of determining corrective measures to be applied during operation of the optical system (104) thus established. 10), wherein the target assembly model (SMM) is a virtual assembly state of the virtual individual parts. One or more virtual target positions (P ｔａｒｇｅｔ ) and A computer program product that directs the execution of.

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