Sound generation using optical cavitation

Abstract

The present invention relates to a method for reducing a first pressure fluctuation in a fluid in a fluid-conducting element of a temperature-control device for a directly position-sensitive or shape-sensitive or an indirectly position-sensitive or shape-sensitive element of a lithography system, the method comprising: detecting information associated with the first pressure fluctuation in the fluid-conducting element; determining, on the basis of the detected information, an optical power to be introduced into the fluid-conducting element in order to counteract the first pressure fluctuation; and introducing the determined optical power into the fluid in the fluid-conducting element in order to produce a cavitation bubble in the fluid, as a result of which a second pressure fluctuation is generated in the fluid which counteracts the first pressure fluctuation.

Description

[0001] Carl Zeiss SMT GmbH

[0002] 1

[0003] SOUND GENERATION BY OPTICAL CAVIATION

[0004] The present invention relates to a method, a device and a computer program as well as a lithography system for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element of the lithography.

[0005] The content of priority application DE 10 2024 139 180.4 is fully incorporated by reference.

[0006] Microlithography is used to manufacture microstructured components, such as integrated circuits. The microlithography process is carried out using a lithography system, which includes an illumination system and a projection system. The image of a mask (reticule) 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 positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.

[0007] Driven by the pursuit of ever smaller structures in the production of integrated circuits, EUV lithography systems are currently being developed that utilize light with wavelengths ranging from 0.1 nm to 30 nm, particularly 13.5 nm. Since most materials absorb light of this wavelength, such EUV lithography systems must employ reflective optics, i.e., mirrors, instead of the previously used refracting optics, i.e., lenses. Carl Zeiss SMT GmbH

[0008] 2

[0009] Illuminating the reflective surface of a mirror with light (such as EUV light) can cause the mirror itself to heat up (e.g., the EUV mirrors of an EUV lithography projection lens (POB)). Similarly, supporting and measuring elements (or their structures) can also heat up, for example, due to differential heat transfer. This is also known as mirror heating. This can alter the optical properties of the mirror and thus undesirably affect the imaging properties of a mask structure onto a substrate. This, in turn, can ultimately lead to an undesirable degradation of the lithography process.

[0010] In some cases, the heating of a mirror can be counteracted by providing cooling for the mirror in question. Cooling can be achieved, for example, by transporting a cooling fluid through the mirror. This cooling fluid can be transported, for instance, from a water tank, which can act as a reservoir for the cooling fluid, to the relevant water-cooled EUV mirrors of an EUV lithography projection lens during operation of an EUV scanner. The cooling fluid can be transported through a suitable fluid line, which can consist, for example, of pipes and / or structured channels, where "pipeline" can be used synonymously with "structured fluid line."

[0011] In some cases, a mechanical short circuit can occur in the piping system that connects the water reservoir to the mirror. This can cause vibrations, for example those generated by a pump connected to the water reservoir, to propagate through the fluid and along the piping system, ultimately transmitting them (with nearly constant intensity) to the mirror. This can also undesirably affect the imaging properties of the Carl Zeiss SMT GmbH

[0012] 3

[0013] Mirrors contribute to this. These pressure fluctuations can be caused by two main phenomena (and subsequently propagate along a piping system). These include, for example, flow-induced pressure disturbances (fluid-induced vibrations), which are primarily generated by flow-internal mechanisms such as turbulence and act locally and / or non-locally through sound transmission. All pressure disturbances propagated in the fluid column, which are also dynamically generated, for example, by accelerated sub-elements of the fluid column (e.g., vibrating frames), are subject to the physical phenomenon of waterline acoustics (WLA) as a second source of pressure fluctuations.

[0014] In particular, the vibrations at the mirror caused by fluid-acoustic pressure fluctuations can occur in a frequency range sensitive to the imaging dynamics of the mirror. These vibrations can manifest as pressure and / or force amplitudes at the mirror body, which can lead to deflections (e.g., displacements and / or displacements of the mirror) and changes in the mirror's cross-section. If left uncorrected, this can lead to high line-of-sight (LoS) contributions, which can significantly reduce the image quality at the wafer level.

[0015] Depending on the sensitivity of the mirror control system, frequency-dependent forces can lead to significant loss of sensitivity (LoS) values ​​in response to disturbances in the respective frequency range. To reduce the resulting pressure amplitudes in the sensitive frequency range, active reduction measures such as a controlled noise cancellation (ANC) system can be used. When using ANC, actuators (e.g., of piezoelectric design) are connected to the piping structure. These actuators can generate an anti-phase pressure signal (in the sense of anti-noise) and couple it into the piping system, thus creating a desired effect at a specific location in the cooling line.

[0016] 4

[0017] Sound cancellation can occur through destructive interference. The use of movable, mechanical structures, which also require coupling to the piping system, can again induce undesirable reaction forces or accelerations.

[0018] Besides using actuators, it may also be possible to actively modify the stiffness of existing passive WLA (Water-Line Acoustics) hardware to generate an anti-sound pressure signal. Both approaches aim to vary a structural mechanical quantity and convert it into a fluid mechanical quantity, such as a pressure signal. However, the coupling between structural mechanics and fluid can, in addition to the desired sound pressure, also result in an undesired reaction force or acceleration of the structure, further complicating the complete compensation of unwanted pressure fluctuations.

[0019] Additionally or alternatively, it may also be possible to provide further element solutions to reduce the pressure amplitudes in the sensitive frequency range, such as viscoelastic hoses, silencers (Helmholtz resonators as branch lines that can be placed on a main pipe of the piping system), routing dynamic links (Helmholtz resonator that can be inserted into the main pipe).

[0020] Therefore, there is a need to further improve the fluid cooling of a mirror.

[0021] Against this background, one objective of the present invention is, in particular, to further improve the reduction of fluid acoustic disturbances in cooling fluids of a lithography system. Carl Zeiss SMT GmbH

[0022] 5

[0023] Consequently, a method for reducing a first pressure fluctuation in a fluid within a fluid-carrying element of a temperature control device for a directly position- or shape-sensitive element or an indirectly position- or shape-sensitive element of a lithography system is proposed according to a first aspect. The method can include acquiring information associated with the first pressure fluctuation in the fluid-carrying element and determining, based on the acquired information, an optical power to be introduced into the fluid-carrying element to counteract the first pressure fluctuation. Furthermore, the method can include introducing the determined optical power into the fluid of the fluid-carrying element to generate a cavitation bubble in the fluid, thereby generating a second pressure fluctuation in the fluid that counteracts the first pressure fluctuation.

[0024] The procedure can be executed once. In some cases, the procedure can also be executed repeatedly. Repeated execution of the procedure can enable a control loop to counteract pressure fluctuations over time.

[0025] According to a second aspect, a method for reducing parasitic vibrations in a lithography system is proposed, wherein a first pressure fluctuation in a fluid of a temperature control device of the lithography system is detected and, depending on the first pressure fluctuation, an optical power is introduced into the fluid, thereby generating a second pressure fluctuation which at least partially cancels out the first pressure fluctuation.

[0026] The temperature control device can be provided as a device for stabilizing the temperature of a directly position- or shape-sensitive element or an indirectly position- or shape-sensitive element. Carl Zeiss SMT GmbH

[0027] 6

[0028] The fluid-carrying element can have a first end and a second end, with the first end being fluid-connected to a source of potential first pressure fluctuations. The second end of the fluid-carrying element, on the other hand, can be fluid-connected to the directly position- or shape-sensitive element or the indirectly position- or shape-sensitive element.

[0029] The information can be associated with a measured value that may indicate the presence of a pressure fluctuation in the fluid. The first and / or second pressure fluctuation may be a fluid acoustic wave.

[0030] The specified optical power can be associated with a certain number of photons to be supplied, with each photon having a specific energy. The optical power can also be associated, either additionally or alternatively, with the duration of a time interval during which the specified optical power is supplied.

[0031] The amplitude and frequency of the second pressure fluctuation can, for example, depend on the specific optical power.

[0032] By introducing a specific optical power, a conversion of photon power into fluid-mechanical power (e.g., into the second pressure fluctuation) is possible. This can occur without generating parasitic structural-mechanical reaction forces.

[0033] This can enable efficient and purely optical decoupling of the directly position- or shape-sensitive element, or the indirectly position- or shape-sensitive element, from a second end of the fluid-carrying element. Thus, pressure fluctuations coupled into the fluid at one end of the fluid-carrying element can at least be reduced, thereby improving the performance of the Carl Zeiss SMT GmbH system.

[0034] 7. Improved cooling of the directly position- or shape-sensitive element or the indirectly position- or shape-sensitive element is provided without transmitting unwanted vibrations to the directly position- or shape-sensitive element or the indirectly position- or shape-sensitive element. Furthermore, the method presented herein can prevent the generation of new pressure fluctuations in the fluid (e.g., by WLA, FIV, or parasitic structural vibrations) that can arise from an attempt to reduce the initial pressure fluctuation.

[0035] In one embodiment, the introduction of optical power can include the introduction of laser power into the fluid.

[0036] In some cases, the optical power can be provided as monochromatic laser light, i.e., originating from a single laser source. Alternatively, the optical power can also be provided as polychromatic laser light, i.e., originating from more than one laser source.

[0037] In some cases, the laser may be an infrared (IR) laser. In some cases, the laser may be a UV-IR laser with a wavelength in the range of 100–3000 nm.

[0038] The laser light can be provided as continuous wave (CW) laser light. In some cases, the laser light can be provided as pulsed laser light.

[0039] In this way, the optical power can be efficiently collimated and provided at a desired (monochromatic) wavelength. This can contribute to improved and controlled cavitation bubble generation. Carl Zeiss SMT GmbH

[0040] 8

[0041] In a further embodiment, the introduction of the optical power into the fluid can comprise the introduction of the optical power by means of a light-carrying fiber, the end of which facing away from an optical power source is attached to the fluid-carrying element, and wherein the generation of the cavitation bubble can preferably be based at least partially on at least local heating of the fluid-carrying element at least at one location of the end of the optical fiber by the optical power.

[0042] In some cases, the optical power source can be a light source, such as an LED, a laser, etc.

[0043] In some cases, the light-carrying fiber can be provided as a single optical fiber. The optical fiber can be configured to carry monochromatic light (e.g., without significant attenuation). Alternatively, the optical fiber can also be configured to carry polychromatic light (e.g., without significant attenuation).

[0044] In some cases, the optical power exiting the light-carrying fiber can at least partially strike the outer surface of the fluid-carrying element and heat it, at least locally. This local heating can cause at least some of this thermal energy to be transferred to the fluid, generating the cavitation bubble.

[0045] Alternatively, it may also be possible for the optical fiber to protrude into the interior of the fluid-carrying element (and thus into the fluid) and for the energy conducted through the optical fiber to be transferred directly to the fluid.

[0046] Using fiber optic cables can simplify and flexibly deliver optical power to a desired location. Carl Zeiss SMT GmbH

[0047] 9

[0048] In a further embodiment, the introduction of the optical power can include the introduction of the optical power by means of a free jet guidance through an opening in the fluid-carrying element that is transparent to the optical power.

[0049] Free-jet guidance can be understood as guiding optical power through free space (e.g., in a vacuum or under normal conditions). Guiding the optical power can include focusing the optical power (e.g., by using at least one lens) and / or deflecting the optical power (e.g., by using at least one mirror).

[0050] The transparent opening can be provided as a window transparent to the optical performance, which can be inserted into the fluid-carrying element and preferably seals the fluid-carrying element in a fluid-tight manner.

[0051] In this way, optical performance can be provided efficiently and cost-effectively.

[0052] In another embodiment, the cavitation bubble can be generated by periodically modulating the optical power.

[0053] Periodic modulation can involve a periodic increase and decrease of optical power over a period of time (e.g., following a sinusoidal curve).

[0054] The concept of periodic modulation can follow that of optical cavitation by short laser pulse (OC-SLP) or TC. Here, energetic, short light pulses (e.g., laser pulses) can be emitted, which ionize the fluid, i.e., convert it into a plasma phase. Upon collapse of the fluid, Carl Zeiss SMT GmbH

[0055] A compression shock can be emitted from the cavitation bubble generated in 10, which can propagate as a second pressure fluctuation in the fluid.

[0056] Power can be understood as the photon flux per unit of time. Each photon in this flux can be associated with a wavelength-dependent energy.

[0057] In this way, periodic pumping of the cavitation bubble can be achieved, and a specific size (e.g., diameter) of the cavitation bubble can be maintained over time. Furthermore, this allows for pulsation of the cavitation bubble and the periodically modulated second pressure fluctuation signal.

[0058] In another embodiment, the cavitation bubble can be generated by sequentially modulating the optical power.

[0059] Sequential modulation can be understood as an abrupt variation in optical power. In some cases, sequential modulation can involve a step-like increase or decrease in optical power over time. This can be based on the concept of thermo-optical cavitation (TOC) or TC, where a fluid transition, e.g., from a liquid phase to a gas phase, is initiated by the use of a low-power continuous laser (LCW). The cavitation bubble can preferably be generated near a wall (e.g., at a distance of less than 1 cm, 2 cm, 3 cm, etc.) of an inner wall of the fluid-carrying element.

[0060] By sequentially modulating the optical power, a pressure pulse can be generated within the fluid, which can propagate radially symmetrically as a second pressure fluctuation within the fluid. In contrast to periodic modulation of the optical power (as described herein), the Carl Zeiss SMT GmbH

[0061] Sequential modulation offers the advantage that a lower overall optical power is required (e.g., in TOC methods) to generate a second pressure fluctuation in the fluid. In some cases, periodic modulation can utilize a rebound, i.e., a subsequent compression during the contraction of the cavitation bubble, thus building up pressure, density, and the required temperature, thereby enabling a further reduction in power.

[0062] In some cases, multiple cavitation bubbles (at the same location or at different locations) can be generated in the fluid. These cavitation bubbles can be regenerated at different times or through a targeted sequence and combined to form new cavitation bubbles. In this way, a resulting long-time broadband spectrum can ultimately be generated from a multitude of short-time events, i.e., individual cavitation bubbles, to reduce the initial pressure fluctuation.

[0063] This can enable the cavitation bubble to be generated at a desired time (e.g., at increased optical power) followed by a subsequent decay of the cavitation bubble (e.g., at decreased optical power).

[0064] In another embodiment, the method can be configured to reduce the first pressure fluctuation in a dynamic range of 1-1000 Hz.

[0065] The dynamic range can be understood as the range which includes frequencies at which at least the first pressure fluctuation in the fluid can propagate along the fluid-carrying element.

[0066] The process can be carried out in such a way that the cavitation bubble (or a multitude of cavitation bubbles) is generated at a frequency of 1-1000 Hz. Carl Zeiss SMT GmbH

[0067] 12 is used to counteract a corresponding initial pressure fluctuation that may occur in this frequency range.

[0068] This can at least enable a reduction of the initial pressure fluctuation in a dynamic range that may be considered particularly problematic for precise alignment of the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element.

[0069] In a further embodiment, the method can also include determining, based on the acquired information, at least one further optical power to be introduced into the fluid-carrying element in order to counteract the first pressure fluctuation. Furthermore, the method can include introducing the determined at least one further optical power into the fluid-carrying element in order to generate at least one further cavitation bubble in the fluid, which is capable of generating at least one third pressure fluctuation in the fluid, which, together with the second pressure fluctuation, counteracts the first pressure fluctuation.

[0070] The second and third cavitation bubbles can be generated spatially separated from each other within the fluid-carrying element. The second and third cavitation bubbles can propagate along the fluid-carrying element and interfere destructively with the first pressure fluctuation.

[0071] In another embodiment, the optical power can be introduced into a dead water region of the fluid-carrying element.

[0072] A dead zone can be understood as a part or area of ​​the fluid-carrying element that is not directly located in a region of the main flow direction of the fluid within the fluid-carrying element. In some Carl Zeiss SMT GmbH

[0073] 13

[0074] In some cases, the dead water area may be an area located in a T-section branching off from a main part (where the main flow direction of the fluid lies) of the fluid-carrying element.

[0075] In this way, the generation of the cavitation bubble can be enabled in a region of the fluid-carrying element that is not directly in the main flow direction of the fluid, thus preventing undesirable influence on the (laminar) flow of the fluid, which could otherwise be caused, for example, by the generation of additional turbulence and resulting new FIV. This allows for improved generation of the cavitation bubble.

[0076] According to a second aspect, a computer program is proposed. The computer program may include commands that, when executed by a computer, cause it to perform the steps of the procedure as described herein.

[0077] In some cases, a computer program product may also be provided, which may include commands that, when executed by a computer, cause the computer to perform the steps of the procedure as described herein. A computer program product, such as a computer program tool, may be provided or delivered, for example, as a storage medium such as a memory card, USB flash drive, CD-ROM, DVD, or as a downloadable file from a server on a network. This can be done, for example, over a wireless communication network by transmitting a corresponding file containing the computer program product or the computer program tool.

[0078] According to a third aspect, a device for reducing a first

[0079] Pressure fluctuation in a fluid in a fluid-carrying element of a Carl Zeiss SMT GmbH

[0080] 14. A temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element of a lithography system is proposed. The device may include means for detecting the first pressure fluctuation in the fluid-carrying element and means for determining an optical power to be introduced into the fluid-carrying element to counteract the first pressure fluctuation. Furthermore, the device may include means for introducing the determined optical power into the fluid in the fluid-carrying element to generate a cavitation bubble in the fluid, thereby generating a second pressure fluctuation in the fluid, which counteracts the first pressure fluctuation.

[0081] The fluid-carrying element can be provided as at least one pipe. The fluid-carrying element can be provided as a piping system.

[0082] The means for detecting the pressure fluctuation may include means for detecting other fluid-mechanical quantities from which the first pressure fluctuation can be inferred.

[0083] One or more of the algorithms / computer programs described here can be embodied directly in hardware (e.g., using appropriate means), in a software module executed by a processor, or in a combination of both. A software module can reside in random-access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from and write information to the storage medium. Alternatively, the storage medium can also be integrated into the processor. Carl Zeiss SMT GmbH

[0084] 15. The processor and storage medium can be integrated into an application-specific integrated circuit (ASIC). Alternatively, the processor and storage medium can be implemented as discrete components within any component of a mobile computing platform. The computer program can also be executed, for example, on a field-programmable gate array (FPGA).

[0085] According to one embodiment, the fluid-carrying element can be arranged between a fluid reservoir, which preferably comprises a fluid drive means, and the directly position- or shape-sensitive element or the indirectly position- or shape-sensitive element, which is preferably provided as a micromirror of a lithography system.

[0086] In some cases, the fluid drive can be provided as a pump. The fluid drive can be configured to drive a fluid within the fluid-carrying element, resulting in a continuous (possibly laminar) flow of the fluid within the fluid-carrying element.

[0087] In some cases, the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element or micromirror can be provided as an EUV mirror.

[0088] According to another embodiment, the fluid can be liquid water.

[0089] In other cases, the fluid can also be an alcohol or another suitable medium.

[0090] The fluid can act as a cooling fluid, which is designed to dissipate unwanted heat from the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element, if the fluid is Carl Zeiss SMT GmbH

[0091] 16 directly position- or shape-sensitive or indirectly position- or shape-sensitive element through which flow occurs.

[0092] By providing the fluid as water, a cost-effective and energy-efficient cooling medium can be provided for the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element.

[0093] According to a further embodiment, the device may comprise a first means for carrying out the method as described herein and / or a second means for executing the computer program as described herein.

[0094] The first or second means can be provided, as described herein, e.g. as a processor (e.g. as a CPU) and / or as an FPGA.

[0095] According to a fourth aspect, a lithography system is proposed which may include the device as described herein.

[0096] Although the embodiments described herein have been described in isolation from one another, they can nevertheless be combined with each other.

[0097] Aspects and embodiments described in relation to a method can also be implemented within the framework of a device and vice versa.

[0098] In some cases, the aspects and embodiments described herein can be integrated into an optical system. The optical system is preferably a projection optic of the projection exposure system. However, the optical system can also be an illumination system. The projection exposure system can be an EUV lithography system. EUV stands for "Extreme Ultraviolet Laser Sintering" (EUV).

[0099] 17

[0100] Ultraviolet refers to a wavelength of the working light between 0.1 nm and 30 nm. The projection exposure system can also be a DUV lithography system. DUV stands for "Deep Ultraviolet" and refers to a wavelength of the working light between 30 nm and 250 nm. The optical system can, for example, also be used in a DUV lithography system. In some cases, optical systems can also serve as measuring systems for lithography inspection.

[0101] The term "one" should not necessarily be understood as restricting the number to exactly one element. Rather, it can also refer to multiple elements, such as two, three, or more. Similarly, every other counter used here should not be interpreted as restricting the number to the exact number stated. Instead, numerical deviations, both higher and lower, are possible unless otherwise specified.

[0102] Other possible implementations of the invention also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

[0103] Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the exemplary embodiments of the invention described below. The invention will be explained in more detail below with reference to preferred embodiments and the accompanying figures.

[0104] Fig. 1 shows a schematic meridional section of a projection exposure system for EUV projection lithography! Carl Zeiss SMT GmbH

[0105] 18

[0106] Fig. 2 shows a schematic representation of an embodiment of an optical system;

[0107] Figs. 3A and 3B show a cross-section through a device for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device;

[0108] Fig. 4 shows a cross-section through a device for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device;

[0109] Fig. 5 shows a flowchart of a method for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device; and

[0110] Fig. 6 shows a device for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device.

[0111] In the figures, identical or functionally equivalent elements have been labelled with the same reference symbols, unless otherwise indicated. Furthermore, it should be noted that the representations in the figures are not necessarily to scale.

[0112] Fig. 1 shows an embodiment of a projection exposure system 1 (lithography system), in particular an EUV lithography system. One embodiment of the illumination system 2 of the projection exposure system 1 has, in addition to a light or radiation source 3, an illumination optic 4 for illuminating an object field 5 in an object plane 6. In an alternative embodiment, the light source 3 can also be used as a component of the otherwise Carl Zeiss SMT GmbH

[0113] 19 Lighting system 2 must be provided as a separate module. In this case, lighting system 2 does not include light source 3.

[0114] A reticule 7 arranged in the object field 5 is exposed. The reticule 7 is held by a reticule holder 8. The reticule holder 8 can be moved, particularly in a scanning direction, via a reticule displacement drive 9.

[0115] Figure 1 illustrates a Cartesian coordinate system with an x-direction x, a y-direction y, and a z-direction z. The x-direction x runs perpendicular to the plane of the drawing. The y-direction y runs horizontally, and the z-direction z runs vertically. In Figure 1, the scan direction runs along the y-direction y. The z-direction z runs perpendicular to the object plane 6.

[0116] The projection exposure system 1 comprises a projection optic 10. The projection optic 10 serves to image the object field 5 onto an image field 11 in an image plane 12. The image plane 12 is parallel to the object plane 6. Alternatively, an angle other than 0° between the object plane 6 and the image plane 12 is also possible.

[0117] A structure on the reticulum 7 is imaged onto a photosensitive layer of a wafer 13 located in the image plane 12 within the image field 11. The wafer 13 is held by a wafer holder 14. The wafer holder 14 can be moved, particularly along the y-direction y, via a wafer transfer drive 15. The movement of the reticulum 7 via the reticulum transfer drive 9 and of the wafer 13 via the wafer transfer drive 15 can be synchronized.

[0118] Light source 3 is an EUV radiation source. Light source 3 emits, in particular, EUV radiation 16, which is also referred to below as Carl Zeiss SMT GmbH.

[0119] 20. Useful radiation, illumination radiation, or illumination light. The useful radiation 16 has, in particular, a wavelength in the range between 5 nm and 30 nm. The light source 3 can be a plasma source, for example, an LPP source (Laser Produced Plasma, plasma generated using a laser) or a DPP source (Gas Discharged Produced Plasma, plasma generated by gas discharge). It can also be a synchrotron-based radiation source. The light source 3 can be a free-electron laser (FEL).

[0120] The illumination radiation 16 emanating from the light source 3 is focused by a collector 17. The collector 17 can be a collector with one or more ellipsoidal and / or hyperboloid reflective surfaces. The at least one reflective surface of the collector 17 can be illuminated by the illumination radiation 16 at grazing incidence (Gl), i.e., with angles of incidence greater than 45°, or at normal incidence (NI), i.e., with angles of incidence less than 45°. The collector 17 can be structured and / or coated to optimize its reflectivity for the useful radiation and to suppress stray light.

[0121] After the collector 17, the illumination radiation 16 propagates through an intermediate focus in an intermediate focal plane 18. The intermediate focal plane 18 can represent a separation between a radiation source module, comprising the light source 3 and the collector 17, and the illumination optics 4.

[0122] The illumination optics 4 comprise a deflecting mirror 19 and, downstream in the beam path, a first faceted mirror 20. The deflecting mirror 19 can be a flat deflecting mirror or, alternatively, a mirror with a beam-shaping effect that influences the beam beyond the mere deflection effect. Carl Zeiss SMT GmbH

[0123] 21

[0124] The effect is to act. Alternatively or additionally, the deflecting mirror 19 can be designed as a spectral filter, which separates a useful wavelength of the illumination radiation 16 from stray light of a different wavelength. If the first faceted mirror 20 is arranged in a plane of the illumination optics 4 that is optically conjugate to the object plane 6 as a field plane, it is also referred to as a field faceted mirror. The first faceted mirror 20 comprises a plurality of individual first facets 21, which can also be referred to as field facets. Only a few of these first facets 21 are shown in Fig. 1 as examples.

[0125] The first facets 21 can be designed as macroscopic facets, in particular as rectangular facets or as facets with an arcuate or semicircular border contour. The first facets 21 can be designed as planar facets or alternatively as convexly or concavely curved facets.

[0126] As is known, for example, from DE 10 2008 009 600 Al, the first facets 21 can themselves each be composed of a plurality of individual mirrors, in particular a plurality of micromirrors. The first facet mirror 20 can in particular be designed as a microelectromechanical system (e.g., a MEMS system). For details, reference is made to DE 10 2008 009 600 Al.

[0127] Between the collector 17 and the deflecting mirror 19, the illumination radiation 16 runs horizontally, i.e. along the y-direction y.

[0128] In the beam path of the illumination optics 4, a second faceted mirror 22 is arranged downstream of the first faceted mirror 20. If the second faceted mirror 22 is arranged in a pupil plane of the illumination optics 4, it is also referred to as a pupil faceted mirror. The second faceted mirror 22 can also be arranged at a distance from a pupil plane of the illumination optics 4. Carl Zeiss SMT GmbH

[0129] 22. In this case, the combination of the first faceted mirror 20 and the second faceted mirror 22 is also referred to as a specular reflector. Specular reflectors are known from US 2006 / 0132747 Al, EP 1 614 008 Bl and US 6,573,978.

[0130] The second facet mirror 22 comprises a plurality of second facets 23. In the case of a pupil facet mirror, the second facets 23 are also referred to as pupil facets.

[0131] The second facets 23 can also be macroscopic facets, which may, for example, have round, rectangular, or hexagonal edges, or alternatively, facets composed of micromirrors. Reference is also made to DE 10 2008 009 600 Al in this regard.

[0132] The second facets 23 can have planar or alternatively convex or concave curved reflective surfaces.

[0133] The illumination optics 4 thus form a double-faceted system. This basic principle is also known as a honeycomb condenser (EnglJ Fly's Eye Integrator).

[0134] It can be advantageous not to arrange the second faceted mirror 22 exactly in a plane that is optically conjugate to a pupil plane of the projection optics 10. In particular, the second faceted mirror 22 can be arranged tilted relative to a pupil plane of the projection optics 10, as described, for example, in DE 10 2017 220 586 A1.

[0135] With the aid of the second facet mirror 22, the individual first facets 21 are imaged into the object field 5. The second facet mirror 22 is the last Carl Zeiss SMT GmbH

[0136] 23 bundle-shaping or actually the last mirror for the illumination radiation 16 in the beam path in front of the object field 5.

[0137] In another embodiment of the illumination optics 4, not shown, a transmission optic can be arranged in the beam path between the second facet mirror 22 and the object field 5, which contributes in particular to imaging the first facets 21 into the object field 5. The transmission optic can have exactly one mirror, or alternatively two or more mirrors, which are arranged one behind the other in the beam path of the illumination optics 4. The transmission optic can in particular comprise one or two mirrors for normal incidence (Ni mirrors, normal incidence mirrors) and / or one or two mirrors for grazing incidence (GF mirrors, grazing incidence mirrors).

[0138] In the embodiment shown in Fig. 1, the lighting optics 4 has exactly three mirrors after the collector 17, namely the deflecting mirror 19, the first faceted mirror 20 and the second faceted mirror 22.

[0139] In a further embodiment of the lighting optics 4, the deflecting mirror 19 can also be omitted, so that the lighting optics 4 after the collector 17 can then have exactly two mirrors, namely the first faceted mirror 20 and the second faceted mirror 22.

[0140] The mapping of the first facets 21 by means of the second facets 23 or with the second facets 23 and a transmission optic into the object plane 6 is regularly only an approximate mapping.

[0141] The projection optics 10 comprise a plurality of mirrors Mi, which are numbered according to their arrangement in the beam path of the projection exposure system 1. Carl Zeiss SMT GmbH

[0142] 24

[0143] In the example shown in Fig. 1, the projection optics 10 comprises six mirrors M1 to M6. Alternatives with four, eight, ten, twelve, or any other number of mirrors Mi are also possible. The projection optics 10 is a double-obscured optic. The penultimate mirror M5 and the last mirror M6 each have a passage aperture for the illumination radiation 16. The projection optics 10 has an image-side numerical aperture that is greater than 0.5 and can also be greater than 0.6, for example, 0.7 or 0.75.

[0144] The reflective surfaces of the mirrors Mi can be designed as freeform surfaces without an axis of rotational symmetry. Alternatively, the reflective surfaces of the mirrors Mi can be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflective surface shape. The mirrors Mi, like the mirrors of the illumination optics 4, can have highly reflective coatings for the illumination radiation 16. These coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.

[0145] The projection optics 10 has a large object-image offset in the y-direction y between a y-coordinate of a center of the object field 5 and a y-coordinate of the center of the image field 11. This object-image offset in the y-direction y can be approximately as large as a z-distance between the object plane 6 and the image plane 12.

[0146] The projection optics 10 can be anamorphic. In particular, they have different magnifications βx, βy in the x and y directions. The two magnifications βx, βy of the projection optics 10 are preferably (βx, βy) = (+ / - 0.25, + / - 0.125). A positive magnification β indicates a projection without image inversion. A negative magnification β indicates a projection with image inversion. Carl Zeiss SMT GmbH

[0147] 25

[0148] The projection optics 10 thus lead to a reduction in the x-direction x, that is, in the direction perpendicular to the scan direction, in a ratio of 4'1.

[0149] The projection optics 10 lead to a reduction of 8H in the y-direction y, that is, in the scan direction.

[0150] Other magnification ratios are also possible. Magnification ratios with the same sign and absolute values ​​in the x and y directions (x, y), for example with absolute values ​​of 0.125 or 0.25, are also possible.

[0151] The number of intermediate image planes in the x and y directions x, y in the beam path between the object field 5 and the image field 11 can be the same or, depending on the design of the projection optics 10, different. Examples of projection optics with different numbers of such intermediate images in the x and y directions x, y are known from US 2018 / 0074303 A.

[0152] Each of the second facets 23 is assigned to exactly one of the first facets 21 to form an illumination channel for illuminating the object field 5. This can result, in particular, in illumination according to Köhler's principle. The far field is divided into a multitude of object fields 5 with the help of the first facets 21. The first facets 21 generate a plurality of images of the intermediate focus on the second facets 23 assigned to each of them.

[0153] The first facets 21 are each superimposed on a corresponding second facet 23 to illuminate the object field 5 onto the reticle 7. The illumination of the object field 5 is particularly homogeneous and preferably exhibits a uniformity error of less than 2%. Carl Zeiss SMT GmbH

[0154] 26

[0155] Field uniformity can be achieved by superimposing different illumination channels.

[0156] The illumination of the entrance pupil of the projection optics 10 can be geometrically defined by arranging the second facets 23. By selecting the illumination channels, in particular the subset of the second facets 23 that carry light, the intensity distribution in the entrance pupil of the projection optics 10 can be adjusted. This intensity distribution is also referred to as the illumination setting or illumination pupil filling.

[0157] Another preferred pupil uniformity in the area of ​​defined illuminated sections of an illumination pupil of the illumination optics 4 can be achieved by a redistribution of the illumination channels.

[0158] Further aspects and details of the illumination of the object field 5 and, in particular, the entrance pupil of the projection optics 10 are described below.

[0159] The projection optics 10 can, in particular, have a homocentric entrance pupil. This can be accessible. It can also be inaccessible.

[0160] The entrance pupil of the projection optics 10 cannot always be illuminated exactly by the second faceted mirror 22. When the projection optics 10 image the center of the second faceted mirror 22 telecentrically onto the wafer 13, the aperture rays often do not intersect at a single point. However, a surface can be found where the pairwise determined separation of the aperture rays is minimized. This surface represents the entrance pupil or a surface conjugate to it in real space. In particular, this surface exhibits a finite curvature. Carl Zeiss SMT GmbH

[0161] 27

[0162] The projection optics 10 may have different entrance pupil positions for the tangential and sagittal beam paths. In this case, an imaging element, in particular an optical component of the transmission optics, should be provided between the second faceted mirror 22 and the reticle 7. This optical element can accommodate the different positions of the tangential and sagittal entrance pupils.

[0163] In the arrangement of the components of the illumination optics 4 shown in Fig. 1, the second faceted mirror 22 is arranged in a plane conjugate to the entrance pupil of the projection optics 10. The first faceted mirror 20 is arranged tilted relative to the object plane 6. The first faceted mirror 20 is arranged tilted relative to an arrangement plane defined by the deflecting mirror 19. The first faceted mirror 20 is arranged tilted relative to an arrangement plane defined by the second faceted mirror 22.

[0164] Fig. 2 shows a schematic representation of an embodiment of an optical system 200 for a lithography system or projection exposure system 1, as shown, for example, in Fig. 1. Furthermore, the optical system 200 of Fig. 2 can also be used, for example, in a DUV lithography system or measuring machines for lithography inspection.

[0165] The optical system 200 of Fig. 2 can have a plurality of actuable optical elements 210. The optical elements 210 can correspond, for example, to one of the mirrors M1 - M6.

[0166] The optical system 200 can be configured as a micromirror array, wherein the optical elements 210 can be micromirrors (e.g., a micromirror itself, a measuring unit, or a support structure for optical elements). Each micromirror 210 can be actuated by means of an associated actuator 220. Carl Zeiss SMT GmbH

[0167] 28

[0168] For example, a respective micromirror 210 can be tilted about two axes and / or moved in one, two or three spatial axes by means of the associated actuator 220.

[0169] In some examples, the optical element 210 can be provided with at least one fluid-carrying element 230 running within it. The fluid-carrying element 230 can function as a cooling channel and contribute to heat dissipation from the optical element 210, thus cooling the optical element 210.

[0170] The fluid-carrying element 230 can be in fluid communication with a (fluid) reservoir 240. The reservoir 240 can be supplied with a pump to enable the fluid to be propelled in the fluid-carrying element 230.

[0171] The control device 100 controls the respective actuator 220, for example with a control voltage V2. This sets a position of the respective micromirror 210.

[0172] For the sake of clarity, the optical system 200 is shown here only for a single signal path consisting of a control device 100, a control voltage V2, an actuator 220, a micromirror 210, a fluid-carrying element 230, and a reservoir 240. However, within the scope of the optical system 200's design, it is possible to provide the optical system 200 with a multitude of corresponding signal paths. In some cases, it may be possible for multiple fluid-carrying elements 230 to utilize the same reservoir 240.

[0173] Figures 3A and 3B show a cross-section through a device 300 for reducing a first pressure fluctuation in a fluid in a fluid-carrying Carl Zeiss SMT GmbH

[0174] 29

[0175] Element of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element of lithography.

[0176] The device 300 comprises a fluid-carrying element 310 in which a fluid 320 is located, which can propagate within it along a longitudinal direction L, i.e., a longitudinal extension direction, as a substantially laminar and continuous flow. The fluid-carrying element 310 can be inserted between a fluid reservoir R and a directly position- or shape-sensitive element M or an indirectly position- or shape-sensitive element M, thus connecting them via a fluid connection.The directly position- or shape-sensitive or the indirectly position- or shape-sensitive element M can be provided with fluid-carrying channels along which the fluid 320 can spread, thus absorbing energy from the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element M and thereby effectively contributing to cooling the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element. In some cases, the fluid reservoir R can be provided with, for example, a pump, which generates at least a first pressure fluctuation (not shown in Fig. 3A) in the fluid 320 and which can propagate in the fluid 320, thus effectively transmitting a vibration caused, for example, by the pump directly and almost undamped to the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element M.

[0177] The device 300 comprises providing an optical power source 330, which can preferably be provided as a laser. The optical power source provides an optical power 340, such as a laser beam whose power results from the number of photons generated per unit time, preferably multiplied by the energy carried by a single photon. In some cases, the optical power source can be a temporally Carl Zeiss SMT GmbH

[0178] 30 Provide variable power (e.g. by means of a passage that can be opened and / or closed).

[0179] The relevant optical power can represent a time-averaged value of the laser power transmitted within a considered time interval. The optical power can be represented and thus quantified, for example, by forming an integral over the optical power transmitted within a considered time interval, normalized to the duration of that interval.

[0180] To enable the coupling of the optical power 340 into the fluid-carrying element 310, the device 300 may further include a reflective deflecting structure 350 (such as an optical mirror, which reflects at least one wavelength window within which a wavelength of the optical power is located). This can enable the optical power 340 to be directed towards a preferred location.

[0181] Furthermore, the device 300 can comprise at least one focusing element 360. In some cases, the focusing element 360 can be provided as a lens. The focusing element 360 can be provided such that it can focus the optical power 340 (for a wavelength of the optical power 340) onto a desired point.

[0182] The fluid-carrying element 310 can further comprise a transparent aperture 370. The transparent aperture 370 can preferably be provided with transmission properties that exhibit transparency of the transparent aperture 370 for at least one wavelength of the optical power 340. The transparent aperture 370 can be provided such that it fluid-tightly seals the fluid-carrying element 310. Carl Zeiss SMT GmbH

[0183] 31

[0184] The focusing element 360 can be provided in particular (i.e., with a corresponding focal length) such that the optical power 340 is focused on a desired point in the fluid 320 within the fluid-guiding element 310. The focusing can be associated with concentrating the optical power 340 onto an infinitesimally small point. This point can be associated with a focal point of the focusing element 360. At the location of the infinitesimally small point, the optical power 340 can generate at least one cavitation bubble 380 in the fluid 320.

[0185] The introduction of optical power 340 at a location within the fluid 320 can lead to at least local heating of the fluid 320 and may trigger a phase transition of the fluid 320, whereby at least a portion of the fluid 320 is transformed from a liquid phase into a gas phase and / or plasma phase. The volume change within the fluid 320 caused by the phase transition can lead to the formation of the cavitation bubble 380. The size of the cavitation bubble 380, or the rate at which it forms, can depend on the applied optical power 340 itself and / or on the duration for which the optical power 340 is supplied to the fluid 320.

[0186] If the optical power 340 is interrupted or terminated by further photons, or if the cavitation bubble 380 has expanded sufficiently, the temperature inside the cavitation bubble 380 can decrease, contributing to a reduction in the internal pressure. Subsequently, the cavitation bubble 380 can collapse under the surrounding external pressure in the fluid 320.

[0187] The cavitation bubble 380 can lead to the generation of at least one second pressure fluctuation 381 in the fluid 320. This can be caused by the fact that the generation of the cavitation bubble 380 leads to at least a local Carl Zeiss SMT GmbH

[0188] 32

[0189] Displacement of fluid 320 at the point of origin of the cavitation bubble 380 leads to...

[0190] This can lead, at least locally, to a pressure increase in the fluid 320, which subsequently propagates radially (from its point of origin). Furthermore, the second pressure fluctuation can also be caused by the collapse of the generated cavitation bubble 380 over time. This can cause a local pressure drop in the fluid 320 at the point of collapse, which can also propagate radially. Finally, the second pressure fluctuation 381 can propagate as a fluid-acoustic wavefront in the fluid 320, for example, radially from the point of origin of the cavitation bubble 380.

[0191] In some cases, not shown in Fig. 3A, the fluid-carrying element 310 may also be provided with more than one transparent opening 370 (e.g., with two, three, four, five, or more transparent openings arranged along a longitudinal direction of the fluid-carrying element 310). In such a case, it may be possible to generate more than one cavitation bubble 380 in the fluid 320 at different locations. This allows at least one further cavitation bubble 380 to be generated in the fluid 320, which then propagates within the fluid 320. In this way, at least a reduction of the first pressure fluctuation (and possibly also of other pressure fluctuations that are undesirably present in the fluid 320) may be achieved.

[0192] In the context of the present invention, a reduction can be defined as a weakening of, for example, the first pressure fluctuation (e.g., by 10%-40%, preferably by 40%-60%, even more preferably by 60-70%, and most preferably by 70%-99% with respect to an initial pressure difference of the first pressure fluctuation relative to an average pressure of the fluid 320 in the fluid-carrying element 310). Carl Zeiss SMT GmbH

[0193] 33. In some cases, reduction can also be understood as a complete elimination of the first pressure fluctuation.

[0194] Fig. 3B shows the cross-section already shown in Fig. 3A (with the same reference numerals), but at a later time.

[0195] In the case shown in Fig. 3B, the generated cavitation bubble 380 (as described with reference to Fig. 3A) has expanded and / or collapsed, thereby generating at least a second pressure fluctuation 381 in the fluid 320, which propagates in the fluid 320 as described above.

[0196] A first pressure fluctuation 382 also propagates in the fluid 320, which, upon encountering the second pressure fluctuation 381, can lead to at least local destructive interference 383 and thus at least to a reduction of the first pressure fluctuation 382. It should be noted that, even if the pressure fluctuation in Fig. 3B propagates from the position-sensitive element M, propagation does not necessarily have to originate exclusively from this element. It is also conceivable that the pressure wave propagates from the reservoir R.

[0197] In this way, it is possible to reduce or eliminate an initial pressure fluctuation 382 in a fluid 320 flowing within a fluid-carrying element 310, and thus, based purely on optical intervention, to isolate a possible initial pressure fluctuation 382 introduced by the reservoir R from a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element M, thereby preventing a mechanical short circuit between the reservoir R and the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element M. Carl Zeiss SMT GmbH

[0198] 34

[0199] Fig. 4 shows a cross-section through a device 400 for reducing a first pressure fluctuation 480 in a fluid in a fluid-carrying element of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element of lithography.

[0200] The device 400 comprises a fluid-guiding element 410 in which a fluid 420 can spread. The fluid-guiding element 410 can be arranged between a reservoir R and a directly position- or shape-sensitive element M or an indirectly position- or shape-sensitive element M.

[0201] The device 400 may further comprise an optical power source 430 to provide a certain optical power.

[0202] It is noted that the fluid-carrying element 410, the fluid 420, the reservoir R, the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element M and the optical power source 430 can be provided identically to the respective components described with reference to Figs. 3A and 3B.

[0203] In contrast to the embodiment described with reference to Figs. 3A and 3B, the optical power provided by the optical power source 430 is primarily coupled into a light-carrying fiber 440, such as a fiber optic cable.

[0204] The light-carrying fiber 440 can be provided in a flexible and / or bendable form, thus enabling low-maintenance routing between the optical power source and the fluid-carrying element 410. A focusing element (such as a lens, e.g., a gradient lens) can be attached to one end of the light-carrying fiber 440 facing away from the optical power source 430 to focus the light.

[0205] 35 light-carrying fibers 440 transported optical power to focus on a desired point within the fluid 420.

[0206] The light-carrying fiber 440 can project at least partially through a fluid-tight seal 450, which is arranged in a region of the fluid-carrying element 410, and thus be in direct contact with the fluid 420. The dimensions of the relevant section of the light-carrying fiber 440 can be such that the light-carrying fiber 440 does not significantly influence the (laminar) flow of the fluid 420 within the fluid-carrying element 410. The light-carrying fiber 440 can be designed to have low stiffness perpendicular to its longitudinal direction. In particular, the light-carrying fiber 440 can have a small cross-section, such as a cross-section that is at least two orders of magnitude smaller than the length of the light-carrying fiber 440.

[0207] Alternatively, it can also be provided that the light-guiding element 440 does not project into an inner volume of the fluid-guiding element and is instead only attached to an outer surface of the fluid-guiding element 410 (e.g. at the location of the fluid-tight seal 450) and thus only the optical power is introduced from an external environment of the fluid-guiding element 410 into an interior of the fluid-guiding element 410.

[0208] Using a high-guiding fiber 440 can contribute to a flexible and simplified introduction of the optical power into the fluid 420 and may, in the context of free-jet guidance, reduce the laser safety measures required.

[0209] At the point of focusing the optical power, as with reference to Fig.

[0210] As described in sections 3A and 3B, a cavitation bubble 460 can be generated. This can be, according to Carl Zeiss SMT GmbH

[0211] 36, as also described above, contribute to the generation of at least one second pressure fluctuation 470. The at least second pressure fluctuation 470 can propagate radially symmetrically within the fluid 420 and superimpose itself on a first pressure fluctuation 480. This can lead to a destructive interference 490 between the first pressure fluctuation 480 and the second pressure fluctuation 470.

[0212] The first, second, and third pressure fluctuations can each be understood as acoustic waves (e.g., in the sense of a sound wave) propagating through the fluid. The second and third pressure fluctuations can be considered anti-sound waves in this context, which can destructively interfere with the initial sound wave (i.e., the first pressure fluctuation).

[0213] The probability of an undesirable reaction of the generated second pressure wave on the light-carrying fiber 440 can be considered small, since the light-carrying fiber 440 is preferably provided with a low stiffness and due to its small diameter.

[0214] It should be noted that the aspects presented herein can also be incorporated into passively acting WLA components (such as pressure pulse limiters (PPL, Helmholtz resonators)) so that the generated cavitation bubble (or the possibly large number of generated cavitation bubbles) does not interfere with the convective fluid flows within the fluid-carrying element 310, 410.

[0215] In some cases, at least one silencer can be installed inside the fluid-carrying element 310 or 410. This can prevent the cavitation bubble 380 or 460 from interfering with a convective flow of the fluid 320 or 420. Silencers can be designed as a side arm with a Helmholtz resonator chamber. They can be positioned such that Carl Zeiss SMT GmbH

[0216] 37

[0217] Pressure fluctuations can be specifically reduced or even adjusted, i.e., desired fluid modes can be generated in the fluid line.

[0218] Fig. 5 shows a flow diagram of a method 500 for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device for a position-sensitive element of a lithography system.

[0219] In a first step 510, information is acquired which is associated with the first pressure fluctuation in the fluid-carrying element.

[0220] In a second step 520, based on the acquired information, an optical power to be introduced into the fluid-carrying element is determined in order to counteract the first pressure fluctuation.

[0221] In a third step 530, the specified optical power is introduced into the fluid-carrying element to create a cavitation bubble in the fluid, which is suitable to generate a second pressure fluctuation in the fluid, which counteracts the first pressure fluctuation.

[0222] Fig. 6 shows a device 600 for reducing a first pressure fluctuation in a fluid in a fluid-carrying element of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element of a lithography system. The device 600 comprises a detection means 610, a determination means 620, and an introduction means 630.

[0223] The 610 sensor is configured to detect the first pressure fluctuation in the fluid-carrying element. Carl Zeiss SMT GmbH

[0224] 38

[0225] The determining means 620 is configured to determine an optical power to be introduced into the fluid-carrying element in order to counteract the first pressure fluctuation. The introducing means 630 is configured to introduce the determined optical power into the fluid-carrying element in order to generate a cavitation bubble in the fluid, which is capable of generating a second pressure fluctuation in the fluid, which counteracts the first pressure fluctuation. Although the present invention has been described with reference to exemplary embodiments, it is modifiable in many ways and is not limited to the aspects and embodiments described herein.

[0226] Carl Zeiss SMT GmbH

[0227] 39

[0228] REFERENCE MARK LIST

[0229] 1 Projection exposure system

[0230] 2 B lighting system

[0231] 3 light source

[0232] 4 B lighting optics

[0233] 5 object field

[0234] 6 Object level

[0235] 7 reticles

[0236] 8 label holders

[0237] 9 Reticle displacement drive

[0238] 10 Projection optics

[0239] 11 Image field

[0240] 12 Image plane

[0241] 13 wafers

[0242] 14 wafer holders

[0243] 15 W wafer transfer drive

[0244] 16 B lighting beam

[0245] 17 Collector

[0246] 18 Intermediate focus plane

[0247] 19 deflecting mirrors

[0248] 20 first faceted mirror

[0249] 21 first facet

[0250] 22 second faceted mirror

[0251] 23 second facet

[0252] 200 optical system

[0253] 210 optical element

[0254] 220 actuator

[0255] 230 fluid-carrying element

[0256] 240 Reservoir Carl Zeiss SMT GmbH

[0257] 40

[0258] 300 device

[0259] 310 fluid-carrying element

[0260] 320 Fluid

[0261] 330 optical power source

[0262] 340 optical power

[0263] 350 reflective deflection structure

[0264] 360° focusing element

[0265] 370 transparent opening

[0266] 380 Cavitation bubble

[0267] 381 second pressure fluctuation

[0268] 382 first pressure fluctuation

[0269] 383 destructive interference

[0270] 400 device

[0271] 410 fluid-carrying element

[0272] 420 Fluid

[0273] 430 optical power source

[0274] 440 light-carrying fibers

[0275] 450 fluid-tight seal

[0276] 460 Cavitation bubble

[0277] 470 second pressure fluctuation

[0278] 480 first pressure fluctuation

[0279] 490 destructive interference

[0280] 500 procedures

[0281] 510 steps

[0282] 520 steps

[0283] 530 steps

[0284] 600 Device

[0285] 610 means of recording

[0286] 620 means of determination

[0287] 630 means for incorporation Carl Zeiss SMT GmbH

[0288] M directly position- or shape-sensitive or indirectly position- or shape-sensitive element

[0289] ml mirror

[0290] M2 mirror M3 mirror

[0291] M4 mirrors

[0292] M5 mirror

[0293] M6 mirrors

[0294] R Reservoir V2 Control voltage

Claims

Carl Zeiss SMT GmbH 42 PATENT CLAIMS 1. Method (500) for reducing a first pressure fluctuation (382; 480) in a fluid (320; 420) in a fluid-carrying element (230; 310; 410) of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element (M) of a lithography system, comprising: Acquiring (510) information associated with the first pressure fluctuation (382; 480) in the fluid-carrying element (230; 310; 410); Determine (520), based on the acquired information, an optical power (340) to be introduced into the fluid-carrying element (230; 310; 410) in order to counteract the first pressure fluctuation (382; 480); and Introducing (530) the specified optical power (340) into the fluid in the fluid-carrying element (230; 310; 410) to generate a cavitation bubble (380; 460) in the fluid (320; 420), thereby generating a second pressure fluctuation (381; 470) in the fluid (320; 420) that counteracts the first pressure fluctuation (382; 480).

2. Method according to claim 1, wherein the introduction of the optical power (340) comprises the introduction of laser power into the fluid (320; 420).

3. A method according to one of claims 1 or 2, wherein the introduction of the optical power (340) into the fluid (320; 420) comprises the introduction of the optical power (340) by means of a light-guiding fiber (440) whose end facing away from an optical power source (430) is attached to the fluid-guiding element (230; 310; 410), and wherein the generation of the cavitation bubble (360; 460) is preferably based at least partially on at least local heating of the fluid-guiding element (230; 310; 410) at least at one location of the end of the optical fiber (440) by the optical power (340). Carl Zeiss SMT GmbH 43 4. Method according to one of claims 1 - 3, wherein the introduction of the optical power (340) comprises the introduction of the optical power (340) by means of a free jet guidance through an opening (370) transparent to the optical power (340) into the fluid-carrying element (230; 310; 410).

5. Method according to one of claims 1 - 4, wherein the generation of the cavitation bubble (380; 460) is carried out by periodically modulating the optical power (340).

6. Method according to one of claims 1 - 4, wherein the generation of the cavitation bubble (380; 460) is carried out by sequential modulation of the optical power (340).

7. Method according to one of claims 1 - 6, wherein the first pressure fluctuation (382; 480) is reduced in a dynamic range of 1-1000 Hz.

8. Method according to any one of claims 1-7, further comprising: Determine, based on the acquired information, at least one further optical power (340) to be introduced into the fluid-carrying element (230; 310; 410) in order to counteract the first pressure fluctuation (382; 480); and Introducing at least one further optical power into the fluid-carrying element (230; 310; 410) in order to generate at least one further cavitation bubble (380; 460) in the fluid (320; 420), which is suitable to generate at least one third pressure fluctuation in the fluid, which together with the second pressure fluctuation (381; 470) counteracts the first pressure fluctuation (382; 480). Carl Zeiss SMT GmbH 44 9. Method according to one of claims 1 - 8, wherein the optical power (340) is introduced into a dead water region of the fluid-carrying element (230; 310; 410).

10. Computer program comprising instructions which, when the program is executed by a computer, cause it to perform the steps of the method according to one of claims 1 and 9.

11. Device (600) for reducing a first pressure fluctuation (382; 480) in a fluid (320; 420) in a fluid-carrying element (230; 310; 410) of a temperature control device for a directly position- or shape-sensitive or an indirectly position- or shape-sensitive element (M) of a lithography system, comprising: Means for detecting (610) the first pressure fluctuation (382; 480) in the fluid-carrying element (230; 310; 410); Means for determining (620) a fluid-carrying element (230; 310; 410) optical power to be introduced (340) to counteract the first pressure fluctuation (382; 480); and Means for introducing (630) the specified optical power (340) into the fluid (320; 420) in the fluid-carrying element (230; 310; 410) to generate a cavitation bubble (380; 360) in the fluid (320; 420), thereby generating a second pressure fluctuation (381; 470) in the fluid (320; 420) which counteracts the first pressure fluctuation (382; 480).

12. Device according to claim 11, wherein the fluid-carrying element (320; 420) is arranged between a fluid reservoir (R), which preferably comprises a fluid drive means, and the directly position- or shape-sensitive or the indirectly position- or shape-sensitive element (M), which is preferably provided as a micromirror of a lithography system. Carl Zeiss SMT GmbH 45 13. Device according to one of claims 11 or 12, wherein the fluid (320; 420) liquid water.

14. Device according to any one of claims 11-13, further comprising: a first means for carrying out the method according to any one of claims 1-9; and / or a second means for carrying out the computer program according to claim 10.

15. Lithography system (1) comprising the apparatus according to one of the claims 11-14.

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