System for semiconductor technology
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CARL ZEISS SMT GMBH
- Filing Date
- 2025-11-25
- Publication Date
- 2026-06-04
Smart Images
Figure EP2025084232_04062026_PF_FP_ABST
Abstract
Description
25.11.2025 / BR Semiconductor technology facility
[0001] The present application claims priority from German patent application 10 2024 211 302.6, filed on November 26, 2024. The content of that German patent application is incorporated into the present application text by reference.
[0002] The invention relates to a system for semiconductor technology comprising at least one fluid channel for a temperature control medium for temperature control of at least one component of the system.
[0003] In the prior art, semiconductor technology equipment refers to equipment used for the production or testing of microstructured devices or the components required for their manufacture. An example of such equipment is a projection exposure system for photolithography.
[0004] Photolithography is used to manufacture microstructured components, such as integrated circuits. The projection exposure system used comprises an illumination system and a projection system. The image of a mask (also called a reticulum) illuminated by the illumination system is projected in a reduced size onto a substrate, such as a silicon wafer, coated with a photosensitive layer and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate.
[0005] Both in lighting systems and in projection systems, especially projection exposure systems designed for the EUV range, i.e. at wavelengths of For exposures ranging from 5 nm to 30 nm, several optical elements, particularly mirrors, are typically used to achieve the desired image of the mask onto the substrate. Due to the required accuracy, it is essential, especially in projection systems, to ensure that the position of the individual optical elements relative to each other, as well as to the mask and the substrate, changes only within extremely small tolerances, if at all, during operation of the projection exposure system. Furthermore, the shape of the optical elements, particularly the mirror surfaces, must not change, or only within a predefined range. Any change in the position and / or shape of one or more optical elements can lead to a decrease in the image quality of the projection system.
[0006] Corresponding changes in the position and / or shape of one or more optical elements can occur due to heat input into the optical elements or into the structure supporting them. Such heat input inevitably occurs, for example, due to absorption of the illumination radiation by the optical elements, absorption of interfering radiation, particularly in the infrared range, and the heat loss from electrical components in the projection system. To compensate for changes in the position of the optical elements to a certain extent, electrical actuators are known, which, however, themselves emit heat.To avoid or at least minimize changes in the shape of the optical elements from a target shape and to dissipate heat introduced into the projection exposure system, in particular its projection system, it is known to provide at least some of the optical elements and / or other components of the projection exposure system, and in particular the projection system, with fluid channels for the passage of a temperature control fluid – in particular demineralized water. The fluid channels, in particular... Especially in optical elements, they are usually integrated directly into the structure of the optical elements, often in the form of channel-shaped recesses that run inside the structure of the optical element.
[0007] Even though the temperature of the individual components can be well regulated by means of the passage of a temperature control fluid through parts of the projection exposure system, so that the change in the position and / or shape of one or more optical elements due to heat input can be reduced or even completely avoided, it has been shown that the passage of temperature control fluid through the fluid channels provided for this purpose introduces vibrations into the components of the projection exposure system, which can lead to a decrease in image quality, especially when they occur in the projection system.
[0008] The causes of these vibrations introduced by the temperature control fluid include flow-induced vibrations (FIV), which result from the interaction of a mostly turbulent flow with the wall of the fluid channel.
[0009] To reduce such flow-induced vibrations, it is known to optimize the cross-section and course of the fluid channel so that as little turbulence as possible occurs within the flow. Such optimization generally results in larger cross-sections and the smallest possible curvatures of the fluid channel. However, larger cross-sections in particular promote waterline acoustics (WLA), which also contributes to the undesirable vibrations. In WLA, vibrations from mechanical machines, such as a circulation pump, propagate along the pipe through the temperature control fluid, similar to sound in air. The vibrations of the frame or support structure also contribute to this. The forces of the projection optics are transmitted into the fluid through the mechanical connections of the pipes to these structures and propagate as sound waves.
[0010] Even if it may be possible to reduce the overall vibrations introduced by the passage of temperature control fluid to a global minimum by appropriately selecting the cross-section and other design of the fluid channels, where the sum of FIV and WLA vibrations is minimal, the resulting vibrations may still reduce the image quality of a protection exposure system beyond a permissible level.
[0011] The object of the present invention is to provide an alternative or additional means of reducing vibrations generated by a flowing liquid, such as a temperature control medium, particularly in a semiconductor technology system, such as a projection exposure system.
[0012] This problem is solved by a semiconductor technology system according to claim 1. Advantageous further developments are the subject of the dependent claims.
[0013] Accordingly, the invention relates to a system for semiconductor technology comprising at least one fluid channel for a temperature control medium for temperature control of at least one component of the system, wherein the system comprises, spaced apart from one another in series along the fluid channel, first at least two pressure fluctuation measuring devices and then a pressure pulse transmitter, which are connected to a control device, wherein the fluid channel between two adjacent pressure fluctuation measuring devices comprises at least a partial wall made of elastic material, and wherein the control device- The system is designed to determine pressure fluctuations in the temperature control medium moving from the pressure fluctuation measuring devices towards the pressure pulse transmitter from the signals of the pressure fluctuation measuring devices and to control the pressure pulse transmitter appropriately to generate a destructive interference to reduce pressure fluctuations in the temperature control medium.
[0014] The invention recognizes that pressure fluctuations propagating along the fluid channel of a temperature control medium flowing through a semiconductor technology system, similar to sound propagation, can be reduced or even completely eliminated by using destructive interference, comparable to active noise cancellation in audio headphones. For the inventive application of this concept in a fluid channel, it is essential to identify which pressure fluctuations actually propagate from the pressure fluctuation measuring devices towards the pressure pulse sensor, since only such pressure fluctuations can actually be reduced by destructive interference using the pressure pulse sensor.If pressure fluctuations propagating in the opposite direction along the fluid channel were to result in pressure pulses from the pressure sensor, these pulses would not lead to destructive interference, but rather would represent an additional disturbing pressure fluctuation.
[0015] According to the invention, at least two pressure fluctuation measuring devices are provided, which are arranged at a distance from one another along the fluid channel. If the distance between the pressure fluctuation measuring devices and the propagation speed of pressure fluctuations in the temperature control medium are known, the pressure fluctuations that are relevant can be determined from the analysis of the results of the individual pressure fluctuation measuring devices based on the distance and the finite propagation speed. These pressure fluctuations propagate towards the pressure sensor. They are then used to control the pressure sensor in such a way that the desired destructive interference occurs at the pressure sensor and / or in the area that should be kept as free from pressure fluctuations as possible. Naturally, the distance between the pressure sensor and the nearest pressure fluctuation measuring device along the fluid channel, as well as the propagation speed of pressure fluctuations in the temperature control medium, must be taken into account to introduce the destructive pressure fluctuation appropriately.The distance between the pressure pulse transmitter and the pressure fluctuation measuring device adjacent along the fluid channel is preferably chosen to be sufficiently large so that the control device can actually control the pressure pulse transmitter to generate a destructive interference when the pressure fluctuation detected by the pressure fluctuation measuring device reaches the pressure pulse transmitter.
[0016] To optimally compensate for pressure fluctuations with the pressure surge sensor provided according to the invention, it is preferred that the fluid channel in the area between the pressure fluctuation measuring devices and the pressure surge sensor is free of any elements that could generate and / or alter pressure fluctuations. "Free of any elements that could generate and / or alter pressure fluctuations" in this context means that no such elements are arranged in the relevant area of the fluid channel. This ensures that the pressure fluctuation measuring device only detects pressure fluctuations that originate outside the section between the pressure fluctuation measuring devices, which can then be reduced by the pressure surge sensor.If an (additional) pressure fluctuation generating element were arranged between the pressure fluctuation measuring devices, the analysis of the measured pressure values could thereby spread towards the pressure pulse transmitter. The pressure waves can be influenced. In any case, pressure fluctuations generated by such an element arranged between the pressure fluctuation measuring devices and / or the pressure pulse transmitter cannot be directly reduced by the arrangement of pressure fluctuation measuring devices and pressure pulse transmitter according to the invention. Should a pressure fluctuation-generating element nevertheless be provided, destructive interference can be introduced for such pressure fluctuations via the pressure pulse transmitter, provided the element is known precisely and / or additional measurements of pressure fluctuations are taken elsewhere. The same applies to almost unavoidable disturbances caused by the fluid channel itself, e.g., due to boundary layer turbulence or wall friction.
[0017] In semiconductor technology systems, various components are typically traversed by one or more fluid channels for a temperature control medium. Different requirements regularly apply to the individual components with regard to vibrations induced by the temperature control medium flowing through the fluid channels. If an arrangement of pressure fluctuation measuring devices and pressure pulse transmitters according to the invention is intended to reduce pressure fluctuations in the temperature control medium in the area of a specific component of the system, it is preferred if the pressure pulse transmitter is arranged in the fluid channel as close as possible to an area that should be kept as free as possible from pressure fluctuations and between the pressure fluctuation measuring devices and the area to be kept free.It is of course possible to arrange an arrangement according to the invention on both sides of an area to be kept free from pressure fluctuations, wherein the pressure pulse transmitters are then located adjacent to the area and the respective pressure fluctuation measuring devices are located further away from the area. If several sensitive areas along the fluid channel(s) for a temperature control medium in the system for semiconductor technology are exposed to pressure fluctuations in the temperature control medium, the following applies: To keep the circulating medium as free as possible, several arrangements consisting of at least two pressure fluctuation measuring devices and one pressure pulse transmitter can be provided.
[0018] Pressure fluctuation measuring devices are generally suitable for recording pressure fluctuations in the temperature control medium with sufficient accuracy to derive appropriate control signals for the pressure pulse sensor. Assuming a closed, rigid wall in the fluid channel, at least between the pressure fluctuation measuring devices, limits arise for the frequencies of the pressure fluctuations that can still be recorded by the arrangement of pressure fluctuation measuring devices or properly analyzed by the control unit. The lower limit is determined by the signal-to-noise ratio of the pressure fluctuation measuring devices or by comparing the results of several pressure fluctuation measuring devices and can, for example, be... The upper limit is approximately 0.05 to 0.45 inches, derived from half the wavelength of a pressure fluctuation that results in no amplitude difference between two pressure fluctuation measuring devices, where c is the propagation speed of a pressure fluctuation in the temperature control medium and x is the distance between the two pressure fluctuation measuring devices. For the propagation speed of a pressure fluctuation in water as the temperature control medium in a stainless steel pipe of c = 1413 m / s and an exemplary distance between two pressure fluctuation measuring devices... The measuring device of x = 740mm then results according to the equation 0.05- < f < 0.4 — xx is a range for the frequencies evaluable by the arrangement of the two pressure fluctuation measuring devices for pressure fluctuations from 96 Hz to 765 Hz. If the distance between the two pressure fluctuation measuring devices is only 427 mm, the evaluable frequency range is between 165 Hz and 1323 Hz. Due to structural conditions in semiconductor technology systems, the distances between the pressure fluctuation measuring devices, as well as between the pressure pulse sensor and the pressure fluctuation measuring device adjacent to it along the fluid channel, cannot be made arbitrarily large. At the same time, the range for pressure fluctuations in the temperature control medium that is particularly relevant for components in semiconductor technology systems lies at frequencies below 2000 Hz, preferably below 1000 Hz, and more preferably below 100 Hz.In particular, to ensure coverage of a frequency range that may be especially relevant for reducing pressure fluctuations, even with a small distance between two pressure fluctuation measuring devices due to structural constraints, the fluid channel between two adjacent pressure fluctuation measuring devices includes at least a partial lining made of elastic material. The elastic material can form the entire lining in a section of the fluid channel. If the lining of the fluid channel between two adjacent pressure fluctuation measuring devices is at least partially elastic, the evaluable frequency range shifts downwards. Based on the example above with a distance of 427 mm between two adjacent pressure fluctuation measuring devices, which corresponds to a propagation speed of... While a velocity c = 1413 m / s in a rigid stainless steel pipe yields an evaluable frequency range of 165 Hz to 1323 Hz, an evaluable frequency range of 40 Hz to 800 Hz can be achieved by incorporating a section where the fluid channel is guided through a polytetrafluoroethylene (PTFE) hose element, thus providing a section with an elastic wall. With a corresponding arrangement of a fluororubber (FKM) hose element in the fluid channel, the evaluable frequency range can be shifted, for example, to 5-10 Hz to 100-200 Hz, depending on the type of fluororubber. The final shift of the evaluable frequency range also depends, among other things, on the length, diameter, and / or wall thickness of the hose elements, which a specialist can determine for the respective application with manageable effort.The same applies if the elastic section does not extend over the entire circumference of the fluid channel. It is, of course, also possible to provide several differently designed elastic sections along the fluid channel. In particular, different elastic materials can be used in the sections.
[0020] To adjust the evaluable frequency range, it is also possible for the fluid channel between two adjacent pressure fluctuation measuring devices to include at least one gas space. This gas space, usually separated from the temperature control medium in the fluid channel by a membrane, allows for a downward shift of the evaluable frequency range, similar to an elastic section in the channel wall. The degree of this shift, however, results not only from the material properties and / or the geometric design of the elastic wall or membrane, but also, at least partially, from the compressibility of the gas in the gas space. The compressibility of the gas can be influenced by the type of gas (air, O₂, N₂, CO₂, etc.). and / or the gas pressure and / or the gas space volume can be adjusted.
[0021] The aforementioned measures for shifting the evaluable frequency range can be combined as desired. It is particularly preferred if at least three pressure fluctuation measuring devices are provided, wherein the fluid line between each pair of pressure fluctuation measuring devices is configured differently. This allows different frequency ranges to be evaluated when considering adjacent pressure fluctuation measuring devices in pairs. Consequently, pressure fluctuations over a wider overall frequency range can be reduced via the pressure pulse sensor.
[0022] The system for semiconductor technology can, in particular, be a projection exposure system for photolithography. In projection exposure systems, optical elements, especially mirrors, and / or their mounts can be permeated by fluid channels for temperature control. Vibrations occurring in these components, for example due to pressure fluctuations in the temperature control medium, can adversely affect image quality. However, by a suitable arrangement of pressure fluctuation measuring devices and pressure pulse transmitters according to the invention, these vibrations can be reduced, thereby improving image quality.
[0023] The temperature control medium guided through the fluid channel is usually a liquid.
[0024] The invention will now be described by way of example with reference to the accompanying drawings. These show: Figure 1: a schematic representation of a projection exposure system for photolithography; and Figure 2: a detail of Figure 1.
[0025] Figure 1 shows a projection exposure system 1 for photolithography as an example of a system for semiconductor technology in a schematic meridional section. The projection exposure system 1 comprises an illumination system 10 and a projection system 20.
[0026] The illumination system 10 illuminates an object field 11 in an object plane or reticulum plane 12. The illumination system 10 comprises an illumination radiation source 13, which, in the illustrated embodiment, emits illumination radiation comprising at least useful light in the EUV range, i.e., in particular with a wavelength between 5 nm and 30 nm. The illumination radiation source 13 can be a plasma source, for example, an LPP source (laser-produced plasma) or a DPP source (gas-discharge-produced plasma). It can also be a synchrotron-based radiation source. The illumination radiation source 13 can also be a free-electron laser (FEL).
[0027] The illumination radiation emanating from the light source 13 is first focused in a collector 14. The collector 14 can be a collector with one or more ellipsoidal and / or hyperboloid reflective surfaces. The at least one reflective surface of the collector 14 can be exposed to the illumination radiation 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 14 can be structured and / or coated on the one hand to optimize its reflectivity for the useful radiation and on the other hand to suppress stray light.
[0028] After the collector 14, the illumination radiation propagates through an intermediate focus in an intermediate focal plane 15. If the illumination system 10 is to be constructed in a modular manner, the intermediate focal plane 15 can, in principle, be used for the separation – including structural separation – of the illumination system 10 into a radiation source module, comprising the exposure radiation source 13 and the collector 14, and the illumination optics 16 described below. With such a separation, the radiation source module and the illumination optics 16 then together form a modularly constructed illumination system 10.
[0029] The illumination optics 16 include a deflecting mirror 17. The deflecting mirror 17 can be a planar deflecting mirror or, alternatively, a mirror with an effect that influences the beam shape beyond the mere deflection effect. Alternatively or additionally, the deflecting mirror 17 can be designed as a spectral filter that separates a useful wavelength of the illumination radiation from stray light of a different wavelength.
[0030] The deflecting mirror 17 deflects the radiation originating from the illumination radiation source 13 onto a first faceted mirror 18. If the first faceted mirror 18 is arranged – as in the present case – in a plane of the illumination optics 16 that is optically conjugate to the reticular plane 12 as the field plane, it is also referred to as a field faceted mirror.
[0031] The first faceted mirror 18 comprises a plurality of micromirrors 18' that can be individually pivoted about two mutually perpendicular axes for the controllable formation of facets, each preferably equipped with an orientation sensor (not shown) for determining the orientation of the micromirror 18'. The first faceted mirror 18 is thus a microelectromechanical system (MEMS system), as described, for example, in DE 10 2008 009 600 A1.
[0032] In the beam path of the illumination optics 16, a second faceted mirror 19 is arranged downstream of the first faceted mirror 18, resulting in a double-faceted system, the basic principle of which is also known as a honeycomb condenser (Fly's Eye Integrator). If the second faceted mirror 19 is arranged in a pupil plane of the illumination optics 16 – as in the illustrated embodiment – it is also referred to as a pupil faceted mirror. However, the second faceted mirror 19 can also be arranged at a distance from a pupil plane of the illumination optics 16, in which case the combination of the first and second faceted mirrors 18, 19 results in a specular reflector, as is the case, for example, with... described in US 2006 / 0132747 Al, EP 1 614 008 Bl and US 6,573,978.
[0033] The second faceted mirror 19 need not necessarily be constructed from pivotable micromirrors. Rather, it can also be formed from a manageable number of facets that are significantly larger than micromirrors and are either fixed or tiltable only between two defined end positions. However, as shown, it is also possible to use a microelectromechanical system in the second faceted mirror 19 with a multitude of facets individually rotated by two perpendicular angles to each other. to provide rotating axes pivotable micromirrors 19 ' , each preferably comprising an orientation sensor .
[0034] With the aid of the second faceted mirror 19, the individual facets of the first faceted mirror 18 are projected onto the object field 11, although this is regularly only an approximate projection. The second faceted mirror 19 can be the last beam-forming or even the last mirror for the illumination radiation in the beam path before the object field 11.
[0035] Each of the facets of the second faceted mirror 19 is assigned to exactly one of the facets of the first faceted mirror 18 to form an illumination channel for illuminating the object field 11. This can result in illumination according to Köhler's principle.
[0036] The facets of the first faceted mirror 18 are each imaged superimposed on a corresponding facet of the second faceted mirror 19 to illuminate the object field 11. The illumination of the object field 11 is as homogeneous as possible. It preferably exhibits a uniformity error of less than 2%. Field uniformity can be achieved by superimposing different illumination channels.
[0037] By selecting the illumination channels ultimately used, which is easily achieved by appropriately adjusting the micromirrors 18' of the first faceted mirror 18, the intensity distribution in the entrance pupil of the projection system 20 described below can also be adjusted. This intensity distribution is also referred to as the illumination setting. Furthermore, it can be advantageous not to position the second faceted mirror 19 exactly in a plane that corresponds to a pupil plane of the projection system. The pupil facet mirror 19 can be arranged optically conjugate to a pupil plane of the proction system 20, as described, for example, in DE 10 2017 220 586 A1.
[0038] In the arrangement of the components of the illumination optics 16 shown in Figure 1, the second faceted mirror 19 is arranged in a surface conjugated to the entrance pupil of the projection system 20. Deflection mirror 17 and the two faceted mirrors 18, 19 are each tilted relative to both the object plane 12 and to each other.
[0039] In an alternative embodiment of the illumination optics 16, not shown, a transmission optic comprising one or more mirrors can be provided in the beam path between the second faceted mirror 19 and the object field 11. 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 (Gl mirrors, grazing incidence mirrors). With an additional transmission optic, different positions of the entrance pupil for the tangential and sagittal beam paths of the projection system 20 described below can be taken into account.
[0040] Alternatively, it is possible to dispense with the deflecting mirror 17 shown in Figure 1, for which the faceted mirrors 18 , 19 must then be arranged appropriately opposite the radiation source 13 and the collector 14.
[0041] With the help of the projection system 20, the object field is 11 in the reticulum plane 12 is transferred to the image field 21 in the image plane 22.
[0042] The projection system 20 comprises a plurality of mirrors M. ± , which are numbered according to their arrangement in the beam path of the protective exposure unit 1. Regarding the mirrors M ± These are optical elements 25.
[0043] In the example shown in Figure 1, the projection system 20 comprises six mirrors. up to M6 as optical elements 25. Alternatives with four, eight, ten, twelve or another number of mirrors M ±are also possible. The penultimate mirror M5 and the last mirror M6 each have a passage for the illumination radiation, making the depicted projection system 20 a doubly obscured optic. The projection system 20 has an image-side numerical aperture that is greater than 0.3 and can also be greater than 0.6, for example, 0.7 or 0.75.
[0044] The reflective surfaces of the mirrors M ± can be designed as freeform surfaces without an axis of rotational symmetry. Alternatively, the reflective surfaces of the mirrors M can be ± but can also be designed as aspherical surfaces with exactly one axis of rotational symmetry of the reflecting surface shape. The mirrors M ±Like the mirrors of the lighting optics 16, they can have highly reflective coatings for the illumination radiation. These reflective coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon.
[0045] The projection system 20 has a large object-image offset in the y-direction between a y-coordinate of a center of the object field 11 and a y-coordinate of the center of the image field 21. This object-image offset in the y-direction can be approximately as large as a z-distance between the object plane 12 and the image plane 22.
[0046] The projection system 20 can in particular be anamorphic, i.e. it has in particular different image scales β. x , ß y in the x and y directions. The two image scales ß x , ß y of the pro-ection system 20 are preferably located at (ß x , ßy ) = ( + 0.25, / + - 0.125) . A magnification β of 0.25 corresponds to a reduction in the ratio of 4:1, while a magnification β of 0.125 results in a reduction in the ratio of 8:1. A positive sign for the magnification β indicates a magnification without image inversion, a negative sign indicates a magnification with image inversion.
[0047] Other magnification ratios are also possible. Magnification ratios with the same sign and those with the same absolute value are also possible. x , ß y In the x and y directions, adjustments are possible.
[0048] The number of intermediate image planes in the x- and y-directions in the beam path between the object field 11 and the image field 21 can be the same or different, depending on the design of the projection system 20. Examples of projection systems 20 with different numbers of such intermediate images in the x- and y-directions are known from US 2018 / 0074303 Al.
[0049] Projection system 20 can, in particular, have a homocentric entrance pupil. This may be accessible. However, it may also be inaccessible.
[0050] A reticle 30 (also called a mask) arranged in the object field 11 is exposed by the lighting system 10 and transferred to the image plane 21 by the projection system 20. The reticle 30 is held by a reticle holder 31. The reticle holder 31 can be moved, particularly in one scanning direction, by means of a reticle displacement drive 32. In the depicted- In the tenth embodiment, the scan direction runs in the y-direction.
[0051] The reticule 30 can have an aspect ratio between 1:1 and 1:3, preferably between 1:1 and 1:2, and particularly preferably 1:1 or 1:2. The reticule 30 can be substantially rectangular and is preferably 5 to 7 inches (12.70 to 17.78 cm) long and wide, more preferably 6 inches (15.24 cm) long and wide. Alternatively, the reticule 30 can be 5 to 7 inches (12.70 to 17.78 cm) long and It should be 10 to 14 inches (25.40 to 35.56 cm) wide, and preferably 6 inches (15.24 cm) long and 12 inches (30.48 cm) wide.
[0052] A structure on the reticulum 30 is imaged onto a photosensitive layer of a wafer 35 located in the image plane 22 within the image field 21. The wafer 35 is held by a wafer holder 36. The wafer holder 36 can be displaced, particularly along the y-direction, via a wafer transfer drive 37. The displacement of the reticulum 30 via the reticulum transfer drive 32 and of the wafer 35 via the wafer transfer drive 37 can be synchronized.
[0053] The projection exposure system 1 shown in Figure 1, or its projection system 20, the above description of which essentially reflects known prior art, further comprises a temperature control system 100 with which various components of the projection system 20 can be kept at a set temperature in order to prevent changes in the position and / or shape of the mirrors M xto avoid up to M6 or at least keep it as low as possible.
[0054] In Figure 1 and Figure 2, which is merely an enlargement of part of Figure 1, the temperature control system 100 is shown on the mirror for the sake of clarity. M4 is limited and only shown in a highly schematic way. As indicated, among other things, by the additional inlets and outlets shown with dotted lines, the temperature control system 100 can also be extended via further mirrors M x , M2, M3, M5 and / or M6 as well as other components not shown, such as in particular the support structure to which the mirrors M3 to M6 are attached. It is also possible that the temperature control system 100 controls the temperature of components of the exposure system 10. However, the exposure system 10 may also have its own temperature control system.
[0055] The temperature control system 100 comprises fluid lines 101 for conveying a temperature control medium, a circulation pump 102 for pumping the temperature control medium through the fluid lines 101, and a controllable heat / cold source as element 103 for actively temperature control of the temperature control medium. The fluid lines 101 are connected to a fluid line 26 passing through the mirror M4 to be temperature controlled in such a way that a closed fluid channel 105 is formed for the temperature control medium.
[0056] The circulation pump 102 circulates the temperature control medium, which can be actively regulated to a desired temperature by means of element 103, along or through various components, such as the mirror M4, where heat transfer occurs, causing the corresponding components to gradually approach the actively controlled temperature of the temperature control medium. This is well known in the prior art.
[0057] Element 103 for active temperature control of the temperature control medium can be provided as a heat pump with an electrically operated heating element, which is designed to to add or remove heat from a temperature control medium flowing through a heat exchanger.
[0058] To prevent vibrations from the circulation pump 102 and / or the active temperature control element 103 from being transmitted through the structure, the circulation pump 102 and / or the active temperature control element 103 are generally mechanically decoupled from the projection system 10 as much as possible and arranged at a distance from it. For this reason, the circulation pump 102 and / or the active temperature control element 103 are also regularly arranged outside the evacuable space provided for the optical elements of the projection exposure system 1. The system boundary between the evacuable space and the area with ambient conditions is indicated by the dashed line 90 in Figures 1 and 2.
[0059] In addition to the elements 101, 102, and 103 shown, the temperature control system 100 can include further elements, such as controllable valves. If, with the aid of the temperature control system 100, several components of the projection exposure system 1 are supplied with the temperature control medium in different parallel fluid channels 105, valves can be used to individually adjust the flow rate in the individual fluid channels 105.
[0060] All elements 101, 102, 103 of the temperature control system 100, as well as the fluid line 26 through components of the projection lighting system 1, are designed to generate as few flow-induced vibrations as possible and / or to dampen such vibrations as much as possible. However, the generation of flow-induced vibrations and line acoustics cannot be completely avoided.
[0061] To further reduce the effects of the line acoustics on the mirror M4, an arrangement of 200 made of pressure flux- Pressure fluctuation measuring devices 210 and a pressure surge sensor 220 are provided along the fluid channel 105. The three pressure fluctuation measuring devices 210 and the pressure surge sensor 220 are arranged in series such that, with the flow direction of the temperature control medium, the temperature control medium is first guided past the three pressure fluctuation measuring devices 210 and only then past the pressure surge sensor 220 before flowing through the fluid line 26 in the reflector M4. The pressure fluctuation measuring devices 210 and the pressure surge sensor 220 are connected to a control unit 230. The pressure fluctuation measuring devices 210 are designed to detect even small pressure fluctuations in the temperature control medium, while the pressure surge sensor 220 can introduce corresponding pressure fluctuations into the temperature control medium. The detection and / or...Pressure fluctuations are introduced at the respective location of the pressure fluctuation measuring devices 210 or the pressure surge transmitter 220.
[0062] An identical distance is provided between each adjacent pressure fluctuation measuring device 210 along the fluid channel 105. Between any two of the three pressure fluctuation measuring devices 210, the fluid line 101 additionally has a section in which the wall is formed by an elastic material 215, namely by an inserted tubular element made of polytetrafluoroethylene (PTFE). Any measures that may be necessary to prevent diffusion of the temperature-sensitive medium through the elastic material into the evacuable space are not shown in Figures 1 and 2 for the sake of clarity.
[0063] The control device 230 is designed to analyze the signals of the pressure fluctuation measuring devices 210 in pairs in such a way that the pressure fluctuations propagating from the pressure fluctuation measuring devices 210 towards the pressure pulse transmitter 220 and the mirror M4 are determined. Due to the different distances between the pressure fluctuation measuring devices 210 and due to the lining of the fluid line 105 with an elastic material 215 between two of the three pressure fluctuation measuring devices 210, pressure fluctuations in different frequency ranges can be determined when considering the two outer pressure fluctuation measuring devices 210, the two pressure fluctuation measuring devices 210 adjacent to each other along the fluid channel 105 with the intervening area made of an elastic material 215, and the two pressure fluctuation measuring devices 210 adjacent to each other along the fluid channel 105 without an elastic area in between.
[0064] The pressure fluctuations propagating towards mirror M4, as determined by the control unit 230, are used to appropriately control the pressure pulse transmitter 220 in order to introduce targeted pressure fluctuations into the temperature control medium. These fluctuations reduce the overall pressure fluctuations in the temperature control medium through destructive interference. The propagation speed of the pressure fluctuations from the pressure fluctuation measuring devices 210 to the pressure pulse transmitter 220 must be taken into account, as well as the time required by the control unit 230 to process the signals from the pressure sensors 210 and derive control signals for the pressure pulse transmitter 220.The distance between the pressure pulse transmitter 220 and the adjacent pressure fluctuation measuring device 210 is in any case sufficiently chosen so that the control device 230 can control the pressure pulse transmitter 220 for the purpose of destructive interference also for such pressure fluctuations for the detection of which the signals of the pressure fluctuation measuring device 210 in question must be analyzed.
[0065] In the area between the pressure fluctuation measuring devices 210, the pressure surge transmitter 220 and the mirror M4 are No elements are provided that could introduce an additional pressure fluctuation into the temperature control medium.
[0066] As an alternative to the illustrated design variant, only two pressure fluctuation measuring devices 210 can be provided. This reduces the [effects caused by the] Control device 230 signals to be analyzed and, in principle, also the evaluable frequency range for the pressure fluctuations. For example, by areas with at least partial walls made of elastic material and / or by changing the distance between the two pressure fluctuation measuring devices 210, the frequency range evaluable by two pressure fluctuation measuring devices 210 can often be sufficiently adapted to the frequency range particularly relevant for the respective application.
Claims
25 Patent claims 1. A system for semiconductor technology comprising at least one fluid channel (105) for a temperature control medium for temperature control of at least one component (25, M4) of the system, characterized in that the system comprises at least two pressure fluctuation measuring devices (210) and a pressure pulse transmitter (220) spaced apart in series along the fluid channel (105), which are connected to a control device (230), wherein the fluid channel (105) between two adjacent pressure fluctuation measuring devices (210) at least partially comprises a wall made of elastic material (215), and wherein the control device (230) is configured toto determine pressure fluctuations in the temperature control medium moving from the pressure fluctuation measuring devices (210) towards the pressure pulse transmitter (220) from the signals of the pressure fluctuation measuring devices (210) and to control the pressure pulse transmitter (220) appropriately to generate a destructive interference in order to reduce pressure fluctuations in the temperature control medium.
2. System according to claim 1, characterized in that the fluid channel (105) in the area between the pressure fluctuation measuring devices (210) and the pressure pulse transmitter (220) is free of elements generating pressure fluctuations.
3. System according to one of the preceding claims, characterized in that the distance between the pressure pulse transmitter (220) and the pressure fluctuation measuring device (110) adjacent along the fluid channel (105) is selected to be sufficiently large that the control device (230) can control the pressure pulse transmitter (220) to generate destructive interference. can, if the pressure fluctuation measuring device (210) detected pressure fluctuation reached the pressure surge sensor (220).
4. System according to one of the preceding claims, characterized in that the pressure surge sensor (220) is arranged in the fluid channel (105) as close as possible to an area to be kept as free as possible from pressure fluctuations and preferably between the pressure fluctuation measuring devices (210) and the area to be kept free.
5. System according to one of the preceding claims, characterized in that the wall made of elastic material (215) extends over the entire circumference of the fluid channel (105).
6. System according to one of the preceding claims, characterized in that the fluid channel (105) between two adjacent pressure fluctuation measuring devices (210) comprises at least two differently designed sections with at least partial lining made of preferably different elastic material (215).
7. System according to one of the preceding claims, characterized in that the fluid channel (105) between two adjacent pressure fluctuation measuring devices comprises at least one gas space.
8. System according to one of the preceding claims, characterized in that the system comprises at least three pressure fluctuation measuring devices (210), wherein the fluid channel (105) is located between each- because the two pressure fluctuation measuring devices (210) are each designed differently.
9. System according to one of the preceding claims, characterized in that the system for semiconductor technology is a projection exposure system (1) for photolithography.