Cooling device for cooling a position-sensitive component, cooling system and projection exposure system with cooling device

Abstract

Cooling device for cooling a position-sensitive component (17-19, M1-M6, 35, 36) of a semiconductor lithography system, in particular a projection exposure system. The cooling device comprises a component (40, 50) connected to a cooling line (29) and through which a cooling fluid flows, with an elastic membrane (41, 51) which is in contact with the cooling fluid (44) on an inner surface (42, 52). The cooling device further comprises a mechanical actuator (26, 26') which is configured to exert an adjustable force on the elastic membrane (41, 51) in order to influence the vibration behavior of the elastic membrane (41, 51). The invention further relates to a cooling system and a projection exposure system, each of which has such a cooling device.The actuator allows the vibration behavior of the elastic membrane to be adapted to characteristic frequencies of sound waves within the cooling system, thereby improving sound damping.

Description

[0001] The invention relates to a cooling device for cooling a position-sensitive component of a semiconductor lithography system, in particular a projection exposure system, as well as a cooling system and a projection exposure system comprising such a cooling device.

[0002] Microlithographic projection exposure systems, comprising an illumination system and a projection system, are used to fabricate microstructured components. The image of a mask (also called a "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 (a "photoresist") and positioned in the image plane of the projection system. This transfers the mask structure onto the photosensitive coating of the substrate. In subsequent fabrication steps, the transferred structure is implemented in the substrate, for example, by etching or material deposition.

[0003] Due to ongoing miniaturization in the semiconductor industry and the transition of wavelengths during exposure from DUV (e.g., 193 nm) to EUV (e.g., 13.5 nm), projection systems in exposure units must exhibit high image quality. In EUV (5-20 nm) projection systems, exclusively reflective optical elements are used to project a mask in the object plane onto a substrate in the image plane, for example, with a reduction factor of 8:1. These elements typically comprise a substrate on whose surface, at least in the areas designated as the actual mirror surface, a layer or multilayer arrangement is applied. This layer is designed to reflect radiation at the wavelength intended for exposure (e.g., 13.5 nm) or a corresponding wavelength range.A certain proportion of the EUV radiation is absorbed by the reflective optical elements and converted into heat.

[0004] To achieve high image quality, not only the quality of the individual optical elements of the projection system is important, but also their relative position to one another. To ensure this relative position during the operation of a projection exposure system, it is known to actively cool the individual optical elements as well as other structures such as support and sensor frames to reduce changes in image quality caused by thermal expansion due to temperature fluctuations. Active cooling can also be used in DUV projection exposure systems, which operate with electromagnetic radiation with a wavelength between 120 nm and 300 nm and can incorporate both diffractive and reflective optical elements.

[0005] Active cooling is typically achieved using a cooling fluid that is pumped through pipes or hoses to the elements to be cooled. The optical elements may include recesses or channels through which the temperature-controlled cooling fluid flows. This dissipates heat from the optical surface, i.e., the area exposed to EUV or DUV radiation. Mechanical excitations can occur within the cooling system, for example, from pumps or other moving components in contact with a cooling line. Such excitations can potentially propagate as sound waves within the cooling fluid along the pipes and hoses.If these sound waves reach one of the optical elements or another position-sensitive component, such as the sensor frame, during operation, this can lead to deformation or a change in the position of the optical surface, which can impair image quality. It is generally known (see DE 10 2022 125 354 A1 or DE 10 2021 210 470 A1) to provide silencers within the cooling system to prevent pressure or sound waves from entering the optical elements or other position-sensitive components. These silencers suppress sound waves propagating along cooling lines or at least reduce their amplitude.

[0006] The object of the present invention is to provide a cooling device for cooling a position-sensitive component of a semiconductor lithography system, as well as a projection exposure system comprising such a cooling device, which enables improved suppression of sound waves. This object is achieved by the features of the independent claims. Advantageous embodiments are described in the dependent claims.

[0007] Accordingly, the invention relates to a cooling device for cooling a position-sensitive component of a semiconductor lithography system, in particular a projection exposure system. The cooling device comprises a component connected to a cooling line (29) and through which a cooling fluid flows, with an elastic membrane that is in contact with the cooling fluid on its inner surface, wherein the cooling device further comprises a mechanical actuator which is configured to exert an adjustable force on the elastic membrane in order to influence the vibration behavior of the elastic membrane.

[0008] Within the scope of the invention, it was recognized that sound waves propagating in the cooling system often exhibit characteristic frequencies. Suppressing these frequencies is particularly successful when the vibration behavior of an elastic diaphragm in a silencer is tuned to these frequencies. Furthermore, it was recognized that the characteristic frequencies can shift over the service life of the system being cooled due to aging effects, which can reduce the effectiveness of the silencers. By providing a mechanical actuator that influences the vibration behavior of the elastic diaphragm by exerting an adjustable force, the vibration behavior can be adapted to the characteristic frequencies that change over time.In particular, the cooling device may be provided with a control unit that can send suitable control signals to the mechanical actuator to adjust the adjustable force in such a way as to achieve a desired vibration behavior, which leads to effective suppression of sound waves.

[0009] Furthermore, the aging of the silencer, for example through the embrittlement or stretching of the elastic diaphragm, can also lead to a decrease in the silencer's effectiveness over time. These aging effects can also be counteracted with the help of adjustable mechanical actuators.

[0010] The cooling fluid can be a gas, such as nitrogen or argon. It can also be a liquid, such as cooling water. Alternatively, the cooling fluid can be an evaporative cooling agent, i.e., a two-phase mixture of a liquid and a gas, such as CO2 or butane. The position-sensitive component can be, in particular, an optical element, for example, an EUV mirror in the projection exposure system, a support frame for optical elements, or a sensor frame to which sensors for determining the position of the optical elements are attached. The cooling line connected to the component can be part of the cooling device. The cooling device serves to cool the position-sensitive component insofar as it is designed to direct the cooling fluid towards the component.

[0011] In one embodiment, the actuator is designed to change the tension of the elastic membrane. It can be provided that the actuator exerts a force on a section of the elastic membrane, the force having a component that is directed along a surface of the membrane. In particular, the elastic membrane can be under tensile tension, and this tension can be increased or decreased by means of the actuator. The vibration behavior of an elastic membrane can be described using its natural frequencies. By increasing or decreasing the tensile tension, the natural frequencies can be adjusted as desired—similar to tuning a string or a drum—to match the characteristic sound frequencies of the cooling system.

[0012] In principle, sound waves within the cooling system can be reduced simply by the fact that the sound waves exert a force on the elastic membrane, and the resulting structural deformation causes the membrane to absorb at least some of this force and convert it into heat. It is also possible for the outer surface of the elastic membrane to be in contact with a volume of gas. This gas volume can be enclosed in a fluid-tight manner. In this case, movement of the membrane sets the gas volume in motion, or compresses or expands it, causing the gas to absorb additional energy and thus improving the damping effect.

[0013] The enclosed gas volume compresses and expands simultaneously with the diaphragm's vibrations, thus influencing its vibrational behavior. The system, consisting of the vibrating diaphragm and the compressed gas volume, can be considered a Helmholtz resonator, whose natural frequency depends, among other things, on the size of the gas volume. In one embodiment, the actuator is therefore designed to move the elastic diaphragm in such a way that the enclosed gas volume changes. The volume can be increased or decreased. This provides another way to adapt the natural frequency to a desired characteristic frequency of the sound waves in the cooling system. In this case, the mechanical actuator can be designed to exert a force on a section of the diaphragm that has a component perpendicular to a surface of the diaphragm.It may be provided that the enclosed gas volume can be changed by the actuator by more than 2%, in particular by more than 5%.

[0014] The cooling device component can have a liquid chamber with a first connection for a coolant supply line and a second connection for a coolant outlet, and a gas chamber containing the gas volume, with the elastic membrane separating the liquid chamber from the gas chamber. This design can be easily integrated into a cooling system by connecting the component to existing coolant lines.

[0015] In one embodiment, the component can have an elastic hose element, wherein the elastic membrane is formed by a wall section of the elastic hose element. This design can be implemented particularly easily by using the elastic hose element itself to dampen sound waves. The elastic hose element can be expanded or compressed by forces acting radially to the hose axis, which are generated by pressure fluctuations, so that an inner diameter of the elastic hose element changes in a given section. In addition, pressure changes inside the elastic hose element can locally alter its curvature, thus changing its orientation along the hose axis. Both processes result in a structural change to the elastic hose wall.the elastic membrane formed there, which allows energy from the sound waves to be absorbed.

[0016] The elastic hose element can be an inner hose surrounded by an outer hose. Furthermore, a volume of gas can be fluid-tightly enclosed between the inner and outer hoses. In this case, the gas volume enclosed between the inner and outer hoses forms a Helmholtz resonator. The advantages already explained above also apply to this embodiment.

[0017] In one embodiment, the actuator can be electrically controlled. Furthermore, the actuator can be, in particular, a piezoelectric element. Electrical leads for controlling the actuator can be easily routed and require minimal installation space. Piezoelectric elements also allow for the reliable application of a desired force to the elastic membrane.

[0018] The cooling device can further include a control unit designed to actuate the piezoelectric element and to read the fluid pressure acting on it. Actuation can, in particular, involve applying a first electrical control variable, such as a voltage, to the piezoelectric element. Reading the fluid pressure can involve determining a second electrical quantity, such as current. By measuring the fluid pressure, it is possible, for example, to monitor frequencies present in the cooling circuit. Specifically, the control unit can be configured to adapt a control command for actuating the piezoelectric element based on the read fluid pressure. This allows for immediate responses to changes in the sound frequency.In particular, the control unit may be configured to adjust the control commands for actuating the piezoelectric element based on the read fluid pressure in such a way that currently measured sound frequencies are actively suppressed. If the cooling device is used within an optical system, especially a projection exposure system, the control unit may have an input for receiving an optical performance parameter of the optical system, and the control unit may be configured to adjust a control command for actuating the piezoelectric element depending on the optical performance parameter.

[0019] In one embodiment, the mechanical actuator is designed as an electrically controllable actuator thread. Particularly when the elastic membrane is a section of an elastic hose element, an actuator thread can be used, which, for example, can be wound around the circumference of the hose element. This allows the compressibility or expandability of the hose element to be influenced, thereby adjusting its vibration behavior. It is also possible to route the actuator thread along an axial direction of the elastic hose element. In this way, the hose length can be influenced by the actuator thread, which can also change the natural frequency of the hose element. The actuator thread can be fixed to an outer or inner wall of the hose element or integrated into the wall of the hose element.Actuator threads are generally known from the prior art in connection with the terms "smart textiles" and "artificial muscle fibers" (see in particular "Phan, PT, Thai, MT, Hoang, TT et al. Smart textiles using fluid-driven artificial muscle fibers. Sci Rep 12, 11067 (2022). https: / / doi.org / 10.1038 / s41598-022-15369-2"), so that a detailed description of their function can be omitted here.

[0020] The invention further relates to a cooling system comprising a cooling fluid reservoir, a cooling device according to the invention connected to the cooling fluid reservoir, and a pumping device for conveying a cooling fluid from the cooling fluid reservoir such that the component is permeated by the cooling fluid. The disclosure includes further embodiments of the cooling system, which can be further developed by the features already described in connection with the cooling device.

[0021] The invention further relates to a projection exposure system comprising a cooling system according to the invention. The position-sensitive component can be an optical element, a support frame for optical elements, or a sensor frame for sensors for determining the position of the optical elements. The disclosure includes further embodiments of the projection exposure system, which can be further developed by the features already described in connection with the cooling device.

[0022] The following are exemplary embodiments of the invention with reference to the accompanying drawings. These show: Fig. 1: an embodiment of a projection exposure system according to the invention; Fig. 2: a cooling system according to the invention, which is used in the projection exposure system of the Fig. 1 is in use; Fig. 3: a first embodiment of a cooling device according to the invention, which is part of the cooling system of the Fig. 2 is; Fig. 4: a further embodiment of a cooling device according to the invention; Fig. 5: a further embodiment of a cooling device according to the invention; Fig. 6: an elastic membrane which can be used in a further embodiment; Fig. 7: a further embodiment of a cooling device according to the invention, which is part of the cooling system of the Fig. 2 is; Fig. 8: a further embodiment of a cooling device according to the invention; Fig. 9: Schematic illustrations to explain one way in which the embodiment functions Fig. 8.

[0023] In Fig. Figure 1 schematically illustrates a microlithographic EUV projection exposure system according to the invention. The projection exposure system comprises an exposure beam source 14, an illumination system 10, and a projection system 22, which are operated together in a vacuum chamber 23.

[0024] The exposure source 14 generates electromagnetic radiation in the EUV range, specifically with a wavelength between 5 nm and 30 nm. The exposure radiation emitted by the exposure source 14 is focused by a collector 15 into an intermediate focal plane 16. Exposure radiation passing from the intermediate focal plane 16 is directed by the illumination system 10 into an object plane 12, so that an object field in the object plane 12 is illuminated with uniform radiation intensity.

[0025] The illumination system 10 comprises a deflecting mirror 17, which deflects the illumination radiation onto a first faceted mirror 18. A second faceted mirror 19 is arranged downstream of the first faceted mirror 18. The facets of the first faceted mirror 18 are imaged onto the object plane 12 by the second faceted mirror 19. The portion of the beam path located between the faceted mirror 19 and the object field is also referred to here as the final beam segment of the illumination system 10.

[0026] In the object plane 12, a photomask 13 is arranged, which is imaged onto an image plane 21 by means of a plurality of mirrors M1-M6 of the projection system 22. A structure formed on the photomask 13 is transferred by means of the mirrors M1-M6 onto a radiation-sensitive layer of a wafer 20 arranged in the image plane 21. The photomask 13 is suspended from a first scanning device 24, and the wafer 20 rests on a second scanning device 25, so that the wafer 20 can be exposed in a scanning operation in which the photomask 13 and the wafer 20 are moved synchronously. The photomask 13 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 photomask 13 can be substantially rectangular in shape. The photomask 13 can preferably be 5 to 7 inches long and wide, especially preferably 6 inches long and wide.Alternatively, the photomask can be 5 to 7 inches long and 10 to 14 inches wide, preferably 6 inches long and 12 inches wide.

[0027] In the Fig. In the example shown, projection system 22 comprises six mirrors M1-M6. Alternatives with four, eight, ten, twelve, or any other number of mirrors are also possible. The penultimate mirror M5 and the last mirror M6 each have a passage for the illumination radiation, making projection system 22 a double-obscured optical system. Projection system 22 has an image-side numerical aperture greater than 0.3, and which can also be greater than 0.6, for example, 0.7 or 0.75. The mirrors M1-M6 are fixed to a support frame. The projection exposure system also includes a sensor frame with sensors arranged on it for determining the actual position of the optical elements. For clarity, the support frame and the sensor frame are shown in Fig. Figure 1 is not shown. The sensors can operate, in particular, without contact. The sensor frame is mechanically and thermally almost completely decoupled from the support frame, so that the sensor frame provides a fundamentally unchanging reference system for determining the position of the optical elements. The use of such support and sensor frames is generally known from the prior art (see DE 10 2011 075 393 A1), so that a detailed explanation is unnecessary here.

[0028] The projection system 22 can in particular be anamorphic, i.e. it has in particular different image scales β x , β y in the x and y directions. The two image scales β x , β y of the projection system 22 are preferably located at (β x , β y) - (+ / - 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.

[0029] The reflective surfaces of mirrors M1-M6 can be designed as freeform surfaces without an axis of rotational symmetry. Mirrors M1-M6, like the mirrors of the illumination system 10, include reflective coatings for the illumination radiation. These reflective coatings can be designed as multilayer coatings, in particular with alternating layers of molybdenum and silicon. Despite the highly reflective coatings of the mirrors, a considerable proportion (e.g., 30%) of the illumination radiation is absorbed by the mirrors and converted into heat. This results in a high heat input into mirrors 17, 18, and 19 of the illumination system and mirrors M1-M6 of the projection system 22.

[0030] To prevent heat from causing undesirable deformation or positional changes of the optical elements, the projection exposure system includes a cooling system for cooling the optical elements, the support frame, and the sensor frame. The cooling system has a cooling water reservoir 27. The cooling water is pumped by a pump 28 of the cooling system through a cooling water line 29 into the interior of the vacuum chamber 23. Within the vacuum chamber, the cooling water is conveyed to the optical elements, the support frame, and the sensor frame by means of suitable pipes and lines to cool them during operation. This is shown for clarity in Fig. 1 not shown. After the cooling water has passed the components to be cooled, it reaches a cooling water sink 37 via the cooling water line 29. Since the temperature of the cooling water has increased due to heat transfer from the components to be cooled, it can be cooled down again within the cooling water sink 37 in order to then be directed back to fluid reservoir 27.

[0031] Between the pump unit and the vacuum chamber 23 is a sound-absorbing component 40 connected to the cooling water line 29, which in this case is designed as a Helmholtz resonator. On its way from the pump unit 28 to the projection exposure system, the cooling water flows through the Helmholtz resonator 40. Sound waves generated by the pump unit 28 are at least partially suppressed by the Helmholtz resonator 40. Another Helmholtz resonator 40 is located between the cooling water sink 37 and the vacuum chamber 23. The operation of the Helmholtz resonator is explained in detail below.

[0032] Fig. Figure 2 shows a schematic representation of the cooling system of the Fig. 1 and a schematic representation of some components of the in Fig. 2 projection exposure system shown. The one already in connection with Fig. The elements described in 1 contribute to Fig. The same reference symbols are used. Within the illumination system 10, the cooling water line 29 splits into three parallel strands, each serving to cool one of the mirrors 17, 18, and 19. Upstream of each of the mirrors 17, 18, and 19 is another Helmholtz resonator 40 for sound wave suppression. The mirrors 17, 18, and 19 each have a mirror body with hollow channels through which the cooling water is passed to cool the optical surfaces of the mirrors. Behind the mirrors 17, 18, and 19, the strands of the cooling water line 29 are joined again into a single strand, which then leads to the projection system 22. Another Helmholtz resonator 40 is located between the illumination system 10 and the projection system 22.Within the projection system 22, the cooling water line 29 branches again into several parallel lines, with a first line leading to the support frame 35, a second line to the optical element M1, a third line to the optical elements M2 and M3, and a fourth line to the sensor frame 36. Each line contains further Helmholtz resonators 40 through which the cooling water flows.

[0033] There is very little installation space between mirrors M2 and M3. At this point is a component through which cooling water flows, in this case formed by a flexible hose element 50. The cooling water flows through the flexible hose element 50, and sound waves present within the cooling water are dampened by a deformation of a wall section of the flexible hose element 50. This will be discussed in more detail below in conjunction with the Fig. 7, Fig. 8 to Fig. 9 explained in detail.

[0034] Fig. Figure 3 shows the sound-absorbing component 40, designed as a Helmholtz resonator, in a schematic side cross-sectional view. The component 40 comprises a fluid chamber 48 bounded by a wall 47, with a first fluid connection 46 for connection to a cooling water supply line 29' and a second connection 46' for connection to a cooling water outlet 29''. Cooling water 44, the direction of flow of which is illustrated here by gray arrows, is introduced into the fluid chamber 48 through the cooling water supply line 29'. Sound waves 45 propagate within the cooling water 44, which are Fig. 3 are schematically represented by wavy lines. Adjacent to the liquid chamber 48 are an upper gas chamber 49 and a lower gas chamber 49, each containing a gas volume. Both the liquid chamber 48 and the gas chamber have a circular cross-sectional shape with respect to a section plane oriented perpendicular to the vertical.

[0035] The liquid chamber 48 is separated from the gas chambers 49 by an elastic membrane 41 in each case. Viewed along the vertical axis, the membrane is circular (see figure). Fig. 6) The gas spaces 49 are also fluid-tightly separated from the surrounding environment. Each gas space 49 has a closable opening 55 through which, prior to commissioning the component 40, a gas at a desired pressure was introduced into the gas space. The openings were then closed so that the gas could no longer escape from the gas space 49. It is possible that the openings have closable valves (not shown in detail here) that allow both the initial filling of a gas and, particularly during maintenance of the cooling system, refilling of the gas.

[0036] During operation, the cooling water comes into contact with an inner surface 42 of the elastic membrane 41. This can lead to a transfer of energy from the sound waves 45 to the elastic membrane 41. The elastic membrane 41 can thus be set into vibration, which in Fig. Figure 3 is illustrated by dashed and dotted lines 38, which represent different natural frequencies of the elastic membrane 41. The gas within the gas chamber 49 is periodically compressed and expanded due to the vibrating membrane 41. Both the membrane 41 itself and the gas absorb some of the energy of the sound waves. When a frequency of the sound waves is matched to a natural frequency of the Helmholtz resonator, this leads to effective suppression of the sound waves. Therefore, the amplitude of the sound waves 45 is significantly reduced in the cooling water that exits the fluid chamber 48 via the second fluid connection 46'.

[0037] During operation of the projection exposure system, the natural frequency of the Helmholtz resonator can change, for example, due to the membrane 41 becoming loose or brittle. It is also possible that the characteristic frequency of the sound waves may shift over time, for example, due to changes in water pressure or structural changes in the components generating the sound waves. In this case, the invention makes it possible to exert a force on the elastic membrane 41 using mechanical actuators 26, which in this case are formed by piezoelectric elements, thereby influencing the vibration behavior of the elastic membrane 41. In this particular case, the elastic membrane 41 is clamped between two mechanical actuators 26. The piezoelectric elements 26 are thus attached to the wall 47 with their outer surface and connected to the elastic membrane 41 on their inner surface.In this way, a tensile force can be exerted on the elastic membrane 41 using the piezoelectric elements 26, which results in . Fig. Figure 3 is illustrated by arrows 39. This allows the tension of the diaphragm 41 to be changed. Changing the tension of the diaphragm also changes the natural frequencies of the diaphragm and the Helmholtz resonator. In this way, the Helmholtz resonator can be adapted to the characteristic sound frequencies generated within the cooling system. The piezoelectric elements 26 are connected via electrical leads to a control unit 56, which is designed to apply a suitable electrical voltage to the piezoelectric elements 26 to adjust the mechanical force. Furthermore, the control unit 56 is designed to detect the fluid pressure acting on the piezoelectric elements 26. This makes it possible to adjust the mechanical force to the detected fluid pressure in order to react immediately to pressure changes or changes in sound frequencies.

[0038] Fig. Figure 4 shows a further embodiment of a component 40 of a cooling device according to the invention. The embodiment of the Fig. 4 is analogous to that of the Fig. 3, whereby some reference symbols have been omitted for clarity. The embodiment of the Fig. 4 differs from the embodiment of the Fig. 3 by the fact that the actuators 26 are in the present case designed by a microelectromechanical system (MEMS) that can be electrically controlled by the control unit 56, wherein the actuators are configured to displace the elastic membrane 41 along a direction perpendicular to the surface of the membrane 41. This is in Fig. 4 illustrated by the arrows 39. In the Fig. In the state shown in Figure 4, the lower membrane 41 was displaced downwards relative to the mechanical actuators 26, thereby reducing the volume of the lower gas space 49. This reduction in the gas volume within the gas space 49 changes the natural frequency of the Helmholtz resonator, allowing its vibration behavior to be adapted to the characteristic sound frequencies.

[0039] Fig. Figure 5 shows a further embodiment of a component 40 of a cooling device according to the invention. The embodiment of the Fig. 5 is analogous to that of the Fig. 3, wherein identical elements are provided with the same reference numerals. In contrast to the embodiment of Fig. 3 is the piezoelectric element 26 in the embodiment of the Fig. 5 is positioned at a central position of the membrane 41. As in the embodiment of Fig. 3. With this positioning of the piezo elements, a tensile force can be exerted on the membrane, which is aligned along the membrane surface in order to influence the vibration behavior of the membrane.

[0040] Fig. Figure 6 shows a top view of an elastic membrane 41, which can be used in a further embodiment of a cooling device according to the invention. In this view, it can be seen that the membrane 41, like the membranes of the embodiments of the Fig. 3, Fig. 4 to Fig. 5 is circularly designed. In contrast to the embodiments of the Fig. In this embodiment, several actuators 26 are positioned at intervals between them on the outer surface 43 of the membrane 41. It is possible for at least some of the actuators 26 to be controlled independently of one another in order to exert adjustable forces on the membrane 41 at their respective positions. This makes it possible to generate complex stress patterns, enabling even more targeted control of the vibration behavior. In this embodiment, the actuators 26 can also be formed by piezoelectric elements or MEMS. In this embodiment, the actuators have a square shape and are arranged in a regular grid. In other embodiments not shown here, the positions of the actuators can also be irregularly distributed, and the shape of the actuators can deviate from the square shape.

[0041] In Fig. 7 is the one already in Fig. Figure 2 illustrates a further embodiment of a cooling device according to the invention, in which the component through which the cooling water flows is designed as an elastic hose element 50. The elastic hose element 50 can be – analogous to the embodiment of the Fig. 3 - at its first end to a coolant supply line 29' and at its second end to a coolant outlet 29'' of the cooling system according to the invention. One hose wall of the elastic hose element 50 represents an elastic membrane 51 within the meaning of the present disclosure.

[0042] In the Fig. Figures 7(a) to 7(d) illustrate the modes of movement of the elastic hose element 50, which can be excited by sound waves present within the cooling water and can thus absorb at least some of the energy of the sound waves. In particular, the elastic hose element 50 can move along the direction 54, which is aligned along the vertical and perpendicular to the hose axis (see Figure 7(a) to 7(d)). Fig. 7(a)), as well as along the direction 54', which is also perpendicular to the hose axis of the respective hose section and aligned along the horizontal (see Fig. 7(b)). Furthermore, the elastic hose element can contract or be compressed in the case of a low fluid pressure (illustrated by arrows 58) prevailing within the hose element, and expand in the case of a high fluid pressure (illustrated by arrows 57) (see Fig. 7(d)). Through the respective movement of the elastic hose element 50, at least part of the energy of the sound waves is converted into heat energy, so that the sound waves are dampened.

[0043] The hose wall 51 is provided with several actuators 26, which can be controlled analogously to the actuators already described above in order to influence the vibration behavior of the hose wall. The position of the actuators 26 is only variable in Fig. 7(a) is illustrated by way of example.

[0044] Fig. Figure 8 shows a further embodiment of a component 50 for use in a cooling device according to the invention. The component comprises, as in the embodiment of the Fig. 7 an elastic hose element 51. In contrast to the embodiment of the Fig. In the 7, the elastic hose element 51 is designed as an inner hose arranged within an outer hose 59. The outer hose can be a corrugated hose. Between the inner hose and the outer hose 59 is a gas space 49 containing a volume of gas. The gas space 49 is also sealed fluid-tight by means of end caps 60. The inner hose passes through openings in the end caps 60. When the inner hose expands, the fluid volume enclosed in the gas space 49 is compressed, so that in this case some of the energy can be absorbed by the gas. Conversely, when the inner hose is compressed, the gas volume expands. The gas volume enclosed in the gas space 49 therefore vibrates together with the hose wall 51, so that this embodiment can also be considered a Helmholtz resonator.

[0045] Even in the embodiment of the Fig. 8 Mechanical actuators are provided, which in this case are formed by actuator threads 26'. The actuator threads 26' are embedded in a tube wall of the elastic tube element 51 and connected to a control unit 56 by electrical leads 62. By applying a voltage to the actuator threads 26', they contract, which leads to a corresponding contraction of the section of the tube element 51 connected to the actuator threads.

[0046] In this case, a first actuator thread 26' extends circumferentially around the hose element 51, forming a ring shape. This actuator thread 26' allows the hose element to be locally constricted, thus enabling a local change in the diameter of the hose element. This is in Fig. Figure 9(b) illustrates this with reference to arrows 60. A second actuator thread 26' is aligned parallel to the axial direction of the hose element 51. The length of the hose section can be changed by means of this actuator thread 26'.

[0047] As in Fig. As illustrated in Figure 9(a), several ring-shaped actuator threads 26' can also be positioned side by side around the circumference of the hose section in order to influence the diameter of the elastic hose element 51 at a plurality of positions. Likewise, several actuator threads 26' can be aligned parallel to the hose axis at different circumferential positions. It is also possible for an actuator thread to extend helically around the circumference of the elastic hose element 51 or to have another irregular orientation relative to the hose element (not shown here). QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2022 125 354 A1

[0005] DE 10 2021 210 470 A1

[0005] DE 10 2011 075 393 A1

[0027] Cited non-patent literature

[0000] Phan PT, Thai MT, Hoang TT et al. Smart textiles using fluid-driven artificial muscle fibers. Sci Rep 12, 11067 (2022). https: / / doi.org / 10.1038 / s41598-022-15369-2

[0019]

Claims

[1] Cooling device for cooling a position-sensitive component (17-19, M1-M6, 35, 36) of a semiconductor lithography system, in particular a projection exposure system, comprising a component (40, 50) connectable to a cooling line (29) and through which a cooling fluid flows, with an elastic membrane (41, 51) which is in contact with the cooling fluid (44) on an inner side (42, 52), wherein the cooling device further comprises a mechanical actuator (26, 26') which is configured to exert a controllable force on the elastic membrane (41, 51) in order to influence a vibration behavior of the elastic membrane (41, 51). [2] Cooling device according to claim 1, wherein the actuator (26, 26') is designed to change a tension of the elastic membrane (41, 51). [3] Cooling device according to claim 1 or 2, wherein an outer surface (43, 53) of the elastic membrane (41, 51) is in contact with a volume of gas. [4] Cooling device according to claim 3, wherein the gas volume is enclosed in a fluid-tight manner. [5] Cooling device according to claim 4, wherein the actuator (26, 26') is configured to move the elastic membrane (41, 51) such that the gas volume decreases or increases. [6] Cooling device according to one of claims 3 to 5, wherein the component (40, 50) has a liquid chamber (48) connectable to a cooling fluid supply line (29') and a cooling fluid outlet (29'') and a gas chamber (49) in which the gas volume is located, wherein the elastic membrane (41, 51) separates the liquid chamber (48) from the gas chamber (49). [7] Cooling device according to one of claims 1 to 6, wherein the component (50) comprises an elastic hose element, the elastic membrane (51) being formed by a wall section of the elastic hose element. [8] Cooling device according to claim 7, wherein the elastic hose element is an inner hose surrounded by an outer hose, wherein a volume of gas is enclosed fluid-tight between the inner hose and the outer hose. [9] Cooling device according to any one of claims 1 to 8, wherein the actuator (26, 26') is electrically controllable. [10] Cooling device according to claim 9, wherein the actuator (26, 26') comprises a piezoelectric element. [11] Cooling device according to claim 10, further comprising a control unit (56) for controlling the piezo element and for reading out a fluid pressure acting on the piezo element. [12] Cooling device according to claim 11, wherein the control unit (56) is configured to adapt a control command for controlling the piezo element on the basis of a read-out fluid pressure. [13] Cooling device according to one of claims 9 to 12, wherein the actuator (26, 26') has an actuator filament. [14] Cooling system comprising a cooling fluid reservoir (27), a cooling device connected to the cooling fluid reservoir (27) according to one of claims 1 to 13, and a pumping device (28) for pumping a cooling fluid (44) from the cooling fluid reservoir (27) such that the component (40, 50) is permeated by the cooling fluid (44). [15] Projection exposure system comprising a cooling system according to claim 14, wherein the position-sensitive component (17-19, M1-M6, 35, 36) is an optical element (17-19, M1-M6), a support frame (35) for optical elements or a sensor frame (36) for carrying sensors for determining the position of the optical elements (M1-M6).

Images