Tubular acoustic damping device, fluid delivery system, cooling system and lithographic apparatus

Abstract

The invention provides a tubular acoustic damping device for use in a vacuum environment, the tubular acoustic damping device comprising: an inner conduit comprising a viscoelastic material, the inner conduit having a first end to be connected to a liquid inlet and a second end to be connected to a liquid outlet; an outer shell surrounding the inner conduit, the outer shell being made of a gas-tight material, in which an annular damping space is formed between the inner conduit and the outer shell, in which the outer shell has a main portion and a compliance portion, in which the compliance portion has a first compliance and the main portion has a second compliance, in which the first compliance is greater than the second compliance.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to EP application 23161851.3, filed on 14 March 2023, and European patent application 23195432.2, filed on 5 September 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to tubular acoustic damping devices for use in vacuum environments and fluid delivery systems for use in vacuum environments. The invention also relates to a cooling system including such a fluid delivery system and a photolithography apparatus including such a cooling system. Background Technology

[0004] A photolithography apparatus is a machine configured to apply a desired pattern onto a substrate. For example, a photolithography apparatus can be used in the manufacture of integrated circuits (ICs). For example, a photolithography apparatus can project a pattern at a patterning device (e.g., a mask) onto a radiation-sensitive material (resist) layer disposed on a substrate.

[0005] To project patterns onto a substrate, photolithography equipment can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be formed on the substrate. Compared to radiation with a wavelength of, for example, 193 nm, photolithography equipment using extreme ultraviolet (EUV) radiation in the wavelength range of 4-20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on the substrate.

[0006] Typically, high throughput is desired in lithography equipment. To increase the throughput of EUV lithography equipment, extreme ultraviolet (EUV) radiation should also have increased power. One challenge of achieving higher EUV radiation power is that it heats and deforms optical components such as mirrors in the projection system. This deformation can lead to imaging and overlap errors, commonly referred to as lens or mirror heating errors.

[0007] To mitigate and / or reduce such lens or mirror heating errors, optical components such as mirrors can be directly cooled using a coolant (e.g., water), which is guided through cooling conduits within the respective optical component. While this solution significantly improves temperature control of the optical component, pressure fluctuations generated from various sources can introduce acoustic noise into the optical component. This acoustic noise can have a significant negative impact on the performance of the optical component, and thus affect overlap performance. To reduce acoustic noise, pressure fluctuations in the coolant should be suppressed before reaching the optical component.

[0008] It has been proposed to reduce pressure fluctuations within the coolant via a gas silencer (also known as a Helmholtz resonator). In such a gas silencer, a gas (e.g., air) is used as a spring for the resonant mass of the coolant. A membrane can be arranged within the gas silencer to separate the gas and coolant from each other, preventing the gas from dissolving into the coolant over time.

[0009] Multiple such gas silencers can be used in series in a cooling system. However, due to the resonant quality of the coolant between two or more gas silencers in the cooling system, the placement of the gas silencers may generate low-frequency pressure spikes. These low-frequency pressure spikes can negatively affect the positioning accuracy of optical components, especially those whose position is not actively controlled. Furthermore, acoustic modes (i.e., standing waves) may be generated within the coolant ducts of the cooling system and within the gas silencers. This can lead to undesirable high-frequency pressure spikes in the coolant. These high-frequency pressure spikes can also negatively affect the performance of optical components. Summary of the Invention

[0010] One aspect of the present invention aims to suppress low-frequency and / or high-frequency pressure spikes in the coolant of a cooling system used under vacuum conditions. In particular, one aspect of the present invention aims to provide an acoustic damping device for damping low-frequency and / or high-frequency pressure spikes in the coolant of a cooling system for use under vacuum conditions where prolonged operation is permitted.

[0011] According to one aspect of the present invention, a tubular acoustic damping device for use in a vacuum environment is provided, the tubular acoustic damping device comprising:

[0012] The conduit includes an inner conduit made of viscoelastic material, having a first end to be connected to a liquid inlet and a second end to be connected to a liquid outlet.

[0013] The outer shell surrounding the inner conduit is made of an airtight material.

[0014] The annular damping space is formed between the inner duct and the outer shell.

[0015] The outer shell has a main part and a flexible part, wherein the flexible part has a first flexible amount and the main part has a second flexible amount, wherein the first flexible amount is greater than the second flexible amount.

[0016] According to one aspect of the present invention, a fluid delivery system for use in a vacuum environment is provided, the fluid delivery system comprising:

[0017] Tubular acoustic damping device, the tubular acoustic damping device includes:

[0018] The conduit includes an inner conduit made of viscoelastic material, having a first end to be connected to a liquid inlet and a second end to be connected to a liquid outlet.

[0019] The outer shell surrounding the inner conduit is made of an airtight material.

[0020] The annular damping space is formed between the inner duct and the outer shell.

[0021] The outer casing has a main portion and a flexible portion, wherein the flexible portion has a first flexibility and the main portion has a second flexibility, wherein the first flexibility is greater than the second flexibility, and a first liquid line has a liquid outlet, wherein the first end of the inner conduit is connected to the liquid outlet.

[0022] A second liquid line having a liquid inlet, wherein the first end of the inner conduit is connected to the liquid inlet.

[0023] According to one aspect of the invention, a cooling system for cooling an object is provided, the cooling system including such a fluid delivery system.

[0024] According to one aspect of the present invention, a photolithography apparatus including such a cooling system is provided. Attached Figure Description

[0025] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0026] - Figure 1 A lithography system, including lithography equipment and a radiation source, is described;

[0027] - Figure 2 The cooling system for optical components in a photolithography apparatus is schematically depicted.

[0028] - Figure 3 Showing more details Figure 2 The gas silencer of the cooling system;

[0029] - Figure 4 A first embodiment of the tubular acoustic damping device is shown;

[0030] - Figure 5 A second embodiment of the tubular acoustic damping device is shown;

[0031] Figure 6 shows Figure 5 The first cross section AA of the acoustic damping device;

[0032] Figure 7 shows Figure 5 The second cross section BB of the acoustic damping device;

[0033] - Figure 8 A third embodiment of the tubular acoustic damping device is shown; and

[0034] - Figure 9 A fourth embodiment of the tubular acoustic damping device is shown;

[0035] - Figure 10 A fifth embodiment of the tubular acoustic damping device is shown;

[0036] - Figure 11A and Figure 11B A sixth embodiment of tubular acoustic damping is shown;

[0037] - Figure 12 A seventh embodiment of the tubular acoustic damping device is shown; and

[0038] - Figure 13 An eighth embodiment of the tubular acoustic damping device is shown. Detailed Implementation

[0039] Figure 1 A lithography system including a radiation source SO and a lithography apparatus LA is shown. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an irradiation system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate stage WT configured to support a substrate W.

[0040] The illumination system IL is configured to adjust the EUV radiation beam B before it is incident on the patterning device MA. The illumination system IL may include a faceted field mirror assembly 10 and a faceted pupil mirror assembly 11. Together, the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11 provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. In addition to or instead of the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11, the illumination system IL may include other mirrors or devices.

[0041] After being adjusted in this way, the EUV radiation beam B interacts with the patterning device MA. Due to this interaction, a patterned EUV radiation beam B' is generated. The projection system PS is configured to project the patterned EUV radiation beam B' onto the substrate W. For this purpose, the projection system PS may include multiple optical elements, such as mirrors 13, 14, which are configured to project the patterned EUV radiation beam B' onto the substrate W held by the substrate stage WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B' to form an image with features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 can be applied. Although the projection system PS in Figure 1 The projection system PS is shown as having only two mirrors 13 and 14, but the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0042] The substrate W may include a pre-formed pattern. In this case, the photolithography apparatus LA aligns the image formed by the patterned EUV radiation beam B' with the pattern previously formed on the substrate W.

[0043] The radiation source SO, the irradiation system IL, and / or the projection system PS can provide a relative vacuum, i.e., a small amount of gas (e.g., hydrogen) at a pressure much lower than atmospheric pressure.

[0044] The radiation source SO can be a laser-generated plasma (LPP) source, a discharge-generated plasma (DPP) source, a free-electron laser (FEL) or any other radiation source capable of generating EUV radiation.

[0045] Figure 2 A schematic diagram of a photolithography device (e.g., Figure 1 The projection system PS of a lithography apparatus (LA) comprises the optical elements OE (e.g., mirrors) and the cooling system CS. In practice, the projection system PS may include multiple optical elements, such as multiple mirrors, but... Figure 2 Only one is shown.

[0046] The lithography apparatus includes a base frame (BF) that defines a vacuum environment, i.e., a closed space with pressure significantly lower than atmospheric pressure. The base frame (BF) supports an intermediate frame (IMF), which in turn supports a force frame (FF). Optical elements (OEs) are supported by the force frame (FF). In the illustrated embodiment, the position of the optical element (OE) is actively controlled using an actuator (ACT) disposed between the force frame (FF) and the optical element (OE). The projection system (PS) may also include one or more optical elements whose position is not actively controlled.

[0047] Due to the power of the EUV radiation used in lithography equipment, at least some optical elements (OEs) of the lithography equipment need to be cooled. A cooling system (CS) cools the OEs by supplying coolant (e.g., cooling water) to them. The cooling system (CS) includes cooling system components such as water tanks, pumps, temperature control elements, etc. Because of the limited space within the enclosed space defined by the chassis (BF), these cooling system components are placed outside the enclosed space and are represented in this embodiment as a coolant supply unit (CSU). The coolant supply unit (CSU) is arranged to supply coolant, supplied via a coolant supply conduit (CSC), to the OEs. Within the OEs, the coolant is guided through a cooling conduit (CC). The coolant can be returned from the OEs to the coolant supply unit (CSU) via a coolant return conduit (CRC). In practice, the components of the coolant supply unit (CSU) need not be housed in a single unit (e.g., a housing) but can also be provided as separate components arranged in a suitable location.

[0048] The coolant supply conduit CSC and coolant return conduit CRC are guided to the optical element OE via the base frame BF, intermediate frame IMF, and force frame FF. This creates a physical connection between these corresponding frames BF, IMF, FF and the optical element OE.

[0049] The frame structure allows one frame to vibrate more than the others. Specifically, it allows the underframe (BF) to withstand greater vibrations than the force frame (FF) and the optical element (OE). The frames are isolated from each other by vibration damping devices such as pneumatic isolators and vibration control connections. However, the physical connections of the coolant supply conduit (CSC) and coolant return conduit (CRC) between the respective frames (BF, IMF, FF) and the optical element (OE) can cause undesirable vibrations to be introduced from, for example, the underframe (BF) into the force frame (FF) or the optical element (OE). These vibrations can be propagated through the materials and connections of the coolant supply conduit (CSC) and coolant return conduit (CRC), but can also propagate as pressure fluctuations within the coolant.

[0050] To reduce the propagation of pressure fluctuations within the coolant in the coolant supply conduit CSC and coolant return conduit CRC, the coolant supply conduit CSC and coolant return conduit CRC are equipped with gas silencers GS, also known as Helmholtz resonators.

[0051] Figure 3 This gas silencer GS is shown in more detail. The gas silencer GS includes a silencer chamber SCH having a membrane GLM. The chamber portion of the silencer chamber SCH above the membrane GLM contains coolant and is connected via a connecting conduit CON to one of the coolant supply conduit CSC and the coolant return conduit CRC. The chamber portion of the silencer chamber SCH below the membrane GLM contains gas. The gas (e.g., air) can act as a spring for the resonant mass of the coolant in the coolant supply conduit CSC and / or the coolant return conduit CRC connected to the gas silencer GS via the connecting conduit CON.

[0052] Although gas silencers (GS) can effectively reduce pressure fluctuations in the coolant supply conduit (CSC) and coolant return conduit (CRC), the placement of gas silencers (GS) can generate low-frequency pressure spikes, also known as wobble, due to the resonant quality of the coolant in the CSC and / or CRC between two or more gas silencers (GS). These low-frequency pressure spikes can have a particularly negative impact on the position of passive optical elements (i.e., optical elements whose position is not actively controlled).

[0053] Furthermore, acoustic modes may be generated in the coolant supply conduit (CSC), coolant return conduit (CRC), and muffler chamber (SCH), leading to high-frequency pressure spikes in the coolant. These high-frequency pressure spikes may also negatively impact the positional accuracy of optical elements (OE), thereby affecting the overlap performance of the lithography equipment (LA).

[0054] To suppress low-frequency and high-frequency pressure spikes in the coolant supply conduit CSC and / or coolant return conduit CRC, a tubular acoustic damping device (ADD) can be installed in the coolant supply conduit CSC and / or coolant return conduit CRC.

[0055] Figure 4 A first embodiment of this tubular acoustic damping device (ADD) is shown. The acoustic damping device ADD includes an inner conduit (VIC) made of a viscoelastic material. If the acoustic damping device ADD is installed in the coolant supply conduit (CSC), as... Figure 4 As shown, the inner conduit VIC has a first end connected to the liquid inlet SCI of the first section of the coolant supply conduit CSC, and a second end connected to the liquid outlet SCO of the second section of the coolant supply conduit CSC. Accordingly, if the acoustic damping device ADD is installed in the coolant return conduit CRC, the first end of the inner conduit VIC can be connected to the liquid inlet of the first section of the coolant return conduit CRC, and the second end can be connected to the liquid outlet of the second section of the coolant return conduit CRC. Therefore, the inner conduit VIC forms a continuous liquid line with the first and second sections of either the coolant supply conduit CSC or the coolant return conduit CRC.

[0056] The viscoelastic material of the internal catheter VIC includes at least one of polytetrafluoroethylene, polyurethane, terpolymers including tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, and fluororubber.

[0057] The acoustic damping device ADD also includes an outer shell OSH that surrounds the inner duct VIC. The outer shell OSH is made of a relatively rigid, airtight material. Because the outer shell OSH surrounds the inner duct VIC, it ensures that the inner duct VIC is not directly exposed to the effects of the vacuum environment within the enclosed space defined by the base frame BF. Therefore, the outer shell OSH makes the acoustic damping device ADD suitable for vacuum environments, i.e., spaces with pressures far below atmospheric pressure. The outer shell OSH can be made of metal, such as stainless steel. The outer shell OSH can be corrugated.

[0058] An annular damping space (ADS) is formed between the inner conduit (VIC) and the outer shell (OSH). This annular damping space (ADS) allows the inner conduit (VIC), particularly the viscoelastic material, to deform in response to low-frequency and / or high-frequency pressure spikes, for example, by movement in the radial direction. The annular damping space (ADS) is filled with a gas (such as air or nitrogen) to accommodate the deformation of the inner conduit (VIC), resulting in a volume change in the annular damping space (ADS). The deformation of the viscoelastic material suppresses low-frequency and / or high-frequency pressure spikes.

[0059] The volume change of the annular damping space ADS caused by the deformation of the inner conduit VIC is crucial to the damping function of the acoustic damping device ADD. However, it has been found that over time, the annular damping space ADS may become filled with coolant, such as water, due to coolant permeation through the viscoelastic material. The presence of coolant in the annular damping space ADS can lead to a significant loss of the damping effect of the acoustic damping device ADD.

[0060] Figure 5 A second embodiment of the acoustic damping device ADD is shown. Figure 6 shows a first cross-section AA of the acoustic damping device ADD, and Figure 7 shows a second cross-section BB of the acoustic damping device ADD.

[0061] The acoustic damping device ADD comprises an inner conduit VIC and a housing OSH. The inner conduit VIC is connected between the liquid inlet SCI of the first section of the coolant supply conduit CSC and the liquid outlet SCO of the second section of the coolant supply conduit CSC. The housing OSH surrounds the inner conduit VIC, enabling the acoustic damping device ADD to be used in vacuum environments, such as those defined by the base frame BF. An annular damping space ADS is defined between the housing OSH and the inner conduit VIC, which is used to dampen low-frequency pressure spikes and / or high-frequency pressure spikes, such as… Figure 4 As described in the embodiments.

[0062] The OSH housing has a main section (OMS) and a flexibility section (OCS). The main section (OMS) and... Figure 4 The outer shell of the embodiment basically corresponds to OSH.

[0063] The compliance portion OCS includes a tubular inner wall TIW and a tubular outer wall TOW surrounding and coaxial with the tubular inner wall TIW. The tubular inner wall TIW and the tubular outer wall TOW of the compliance portion OCS define an annular compliance space ACS, which has an open end connected to an annular damping space ADS and a closed end opposite to the open end. The closed end is formed, for example, by an end cap EC.

[0064] The flexible portion of the OCS (Optical System) consists of a tubular inner wall (TIW), a tubular outer wall (TOW), and end caps (EC) made of a hermetically tight, vacuum-compliant material, such as stainless steel. The tubular inner wall (TIW) and the tubular outer wall (TOW) can be corrugated.

[0065] The acoustic damping device ADD includes a longitudinal axis LAD parallel to the central axis of the housing OSH. The compliance portion OCS has an expandable volume along the longitudinal axis LAD, which depends on the internal pressure within the annular compliance space ACS. This expandable volume expands according to the internal pressure within the annular compliance space ACS through a variable gap between the open and closed ends of the compliance portion. Therefore, the tubular inner wall TIW and the tubular outer wall TOW extend along the longitudinal axis LAD to facilitate the variable gap between the open and closed ends.

[0066] The compliance portion OCS has a first compliance, and the main portion OMS has a second compliance. Due to the construction of the compliance portion OCS, the first compliance is greater than the second compliance. Because of the larger compliance of the compliance portion OCS, the acoustic damping device ADD, particularly the annular compliance space ACS, can adjust its volume according to the internal pressure within the annular compliance space ACS. If the annular damping space ADS is filled with coolant over time, the compliance portion OCS will still allow the viscoelastic material to move according to low-frequency and / or high-frequency pressure spikes by utilizing its expandable volume. Therefore, even if the annular damping space ADS and the annular compliance space are completely filled with coolant, i.e., regardless of coolant permeation through the viscoelastic material, the acoustic damping device ADD will be able to effectively dampen low-frequency and / or high-frequency pressure spikes.

[0067] In one embodiment, a first flexibility is selected to provide a rigid construction under normal operating conditions, while a second flexibility is selected to allow the flexibility portion of the OCS to expand under normal operating conditions due to increased internal pressure within the flexibility portion.

[0068] Furthermore, the construction of the compliance portion OCS has the advantage that the first compliance of the compliance portion OCS is generated by the expansion of the expandable volume in the longitudinal axis LAD direction. Therefore, the radial space required by the acoustic damping device ADD is... Figure 4 The acoustic damping device ADD is basically the same. This is particularly advantageous in arrangements with limited radial space.

[0069] Figure 8 A third embodiment of the acoustic damping device ADD is shown.

[0070] In this third embodiment, the outer shell OSH further includes a main portion OMS and a compliance portion OCS, wherein a first compliance of the compliance portion is greater than a second compliance of the main portion OMS. The first compliance is obtained through the expandable volume of the annular compliance space ACS.

[0071] To create an expandable volume, the radially outer portion of the end cap EC is rotatable relative to the radially inner portion of the end cap EC about a pivot PIV. This allows an increase in pressure within the annular compliance space ACS, causing the radially outer portion of the end cap to pivot at the pivot PIV. This allows the tubular outer wall TOW to extend and retract in the direction of the longitudinal axis LAD, thereby altering the volume of the annular compliance space ACS. The pivot PIV can be formed by a relatively flexible portion of the end cap EC.

[0072] The tubular inner wall (TIW) is arranged to provide a sealing wall between the viscoelastic material of the inner conduit (VIC) and the liquid outlet (SCO) of the coolant supply conduit (CSC). The tubular inner wall (TIW) can extend in the direction of the longitudinal axis (LAD), for example, due to its corrugated shape, to allow the viscoelastic material of the inner conduit (VIC) to expand and / or contract in the direction of the longitudinal axis (LAD). Therefore, Figure 8 The embodiments allow the viscoelastic material to move both radially and axially relative to the longitudinal axis LAD. This movement in both the radial and axial directions increases the damping effect of the viscoelastic material.

[0073] Furthermore, to reduce or prevent cooling fluid from penetrating the viscoelastic material of the inner conduit VIC into the annular damping space ADS, the inner conduit VIC may be coated with a coating CLA. The material of the coating CLA is selected to reduce or prevent coolant penetration. The coating may be made of, for example, a metal (e.g., aluminum or nickel) or a polymeric material (e.g., Parylene-C or SoftDLC) or a combination thereof.

[0074] Instead of using a coating CLA that is directly applied to the outer surface of the viscoelastic material of the inner conduit VIC, an impermeable foil can be arranged in the annular damping space ADS between the outer shell OSH and the viscoelastic material of the inner conduit VIC. In this embodiment, the annular damping space ADS can be divided into an inner damping space and an outer damping space by the impermeable foil. The impermeable foil can be made of, for example, a metal (e.g., aluminum or nickel) or a polymer material (e.g., Parylene-C or Soft DLC) or a combination thereof.

[0075] The coating and / or impermeable foil used to reduce or prevent cooling fluid from entering the annular damping space ADS can also be applied to any other embodiment of the tubular acoustic damping device ADD, for example... Figure 4 , Figure 5 and Figure 9 The embodiments disclosed herein.

[0076] Figure 9A fourth embodiment of the tubular acoustic damping device ADD is shown. The tubular acoustic damping device ADD includes an inner conduit VIC made of a viscoelastic material and an outer shell OSH made of an airtight material. The outer shell OSH consists of a main portion OMS and a flexibility portion OCS. The inner conduit VIC and the outer shell OSH define an annular damping space ADS, which is configured to allow damping of low-frequency and / or high-frequency pressure spikes in the coolant of the cooling system CS by deformation of the viscoelastic material.

[0077] The compliance portion OCS includes a tubular inner wall TIW and a tubular outer wall TOW. The tubular inner wall TIW and the tubular outer wall TOW have an open end connected to the annular damping space ADS and a closed end opposite the open end, sealed by an end cap EC. The closed end is formed, for example, by an end cap CE. The tubular inner wall TIW and the tubular outer wall TOW define the annular compliance space ACS therebetween.

[0078] The flexible portion of the OCS, including the tubular inner wall TIW, tubular outer wall TOW, and end cap EC, is made of a gas-tight vacuum flexible material, such as stainless steel or other metals.

[0079] The compliance portion OCS has an expandable volume in the direction of the longitudinal axis LAD, which depends on the internal pressure in the annular compliance space ACS. This expandable volume can be expanded by the extension of the tubular outer wall TOW in the direction of the longitudinal axis LAD. To allow the extension of the tubular outer wall TOW, the end cap EC is pivotable about the pivot PIV. This pivot PIV can be formed, for example, by a flexible connection between the tubular inner wall TIW and the end cap EC.

[0080] exist Figure 9 In this embodiment, a superabsorbent material (SAM) layer is arranged in the annular damping space (ADS) formed between the inner conduit (VIC) and the outer shell (OSH). Over the years, the amount of water permeating the viscoelastic material has been relatively small. Providing a material layer with very high coolant absorption capacity to prevent coolant interference with the damping performance of the acoustic damping device (ADD) is sufficient.

[0081] Superabsorbent material SAM can be directly coated onto the outer surface of the viscoelastic material of the inner catheter VIC, but it can also be a separate layer without being directly attached to the viscoelastic material of the inner catheter VIC.

[0082] Superabsorbent materials (SAMs) are, for example, superabsorbent polymers (SAPs) that comprise hydrophilic homopolymers or copolymers capable of absorbing and retaining large amounts of liquid relative to their own mass. Superabsorbent polymers may, for example, include cross-linked polyacrylates and polyacrylamides, cellulose or starch-acrylonitrile graft copolymers, or cross-linked maleic anhydride copolymers.

[0083] The superabsorbent material SAM does not have to be arranged as a superabsorbent material SAM layer, but can also be provided in any other suitable form or shape.

[0084] The superabsorbent material SAM used to absorb the coolant in the annular damping space ADS can also be applied to any other embodiment of the tubular acoustic damping device ADD, such as... Figure 4 , Figure 5 and Figure 8 The embodiments disclosed herein.

[0085] The above describes an embodiment of an acoustic damping device ADD comprising a housing OSH surrounding the inner conduit VIC. The first compliance of the compliance portion OCS is greater than the second compliance of the main portion OMS of the housing OSH. Due to the compliance portion, the acoustic damping device ADD can still provide effective damping even when the annular damping space ADS is filled with coolant (e.g., water) due to coolant permeation through the viscoelastic material of the inner conduit VIC.

[0086] As mentioned above, different viscoelastic materials are suitable for use in internal conduits (VICs), such as polytetrafluoroethylene (PTFE), polyurethane, terpolymers including tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and fluororubber. To effectively suppress pressure fluctuations, the material needs to be flexible. Viscoelastic materials also need to meet other requirements, such as thermal and permeability requirements.

[0087] FKM (fluorocarbon-based fluororubber) is particularly suitable as a viscoelastic material for the inner conduit (VIC). However, the flexibility of FKM and other suitable materials can lead to relatively large deformations under hydrostatic loads within the inner conduit (VIC). As a result, due to the internal pressure within the inner conduit (VIC), the outer surface of the inner conduit (VIC) can come into contact with the inner surface of the outer shell (OSH).

[0088] For example, in Figure 5 In this embodiment, when internal pressure, such as internal hydrostatic pressure, causes the material of the inner conduit VIC to expand, the flat outer surface of the inner conduit VIC can contact the inner surface of the corrugated outer shell OSH. In practice, the corrugations of the outer shell OSH can have a pitch of, for example, 1 mm. This means that the expanded inner conduit VIC will have a circular contact surface that is 1 mm away from the outer shell OSH. Contact at the circular contact surface with a 1 mm pitch can have a substantial negative impact on the damping capability of the acoustic damping device ADD.

[0089] Figure 10 A fifth embodiment of the acoustic damping device ADD is shown. The main structure of this acoustic damping device ADD corresponds to... Figure 5 The damping device ADD. With Figure 5The main difference in the embodiments is that the outer surface of the inner catheter VIC has an annular protrusion RSE pattern. The annular protrusion RSE pattern can be formed as a thickened portion of the inner catheter VIC, or the inner catheter VIC can be corrugated to form the annular protrusion RSE.

[0090] When the inner catheter VIC expands due to greater internal pressure, such as internal static pressure, the annular protrusions RSE will contact the inner surface of the outer casing OSH. This contact prevents further expansion of the inner catheter VIC. Simultaneously, the annular recesses RSR between the annular protrusions still allow the inner catheter VIC to suppress pressure fluctuations within it.

[0091] The corrugations of the outer casing OSH have a first pitch of, for example, 1 mm. The annular protrusion RSE pattern has a second pitch. The second pitch is greater than the first pitch, for example, at least twice the first pitch, such as at least four times the first pitch. The second pitch can be, for example, approximately 5 mm.

[0092] Because the second pitch is larger than the first pitch, the contact surface area between the outer surface of the inner conduit VIC and the inner surface of the outer shell OSH is reduced. A balance is struck between selecting the second pitch to provide sufficient contact surface between the outer surface of the inner conduit VIC and the inner surface of the outer shell OSH to limit the expansion of the inner conduit VIC, and providing a sufficiently flexible inner conduit VIC to suppress pressure fluctuations.

[0093] Figure 11A and Figure 11B Another embodiment of the inner catheter VIC is shown, which has a pattern of protrusions and / or recesses to reduce contact between the outer surface of the inner catheter VIC and the inner surface of the outer casing OSH. In this embodiment, the outer contour of the cross-section of the inner catheter VIC is not circular, but hexagonal. Due to this shape, a pattern of six longitudinal protrusions LE is formed. The longitudinal protrusions LE can serve as contact surfaces between the inner catheter VIC and the outer casing OSH.

[0094] Figure 11A The inner catheter VIC is shown in an unexpanded or slightly expanded state. There is no contact between the inner catheter VIC and the outer casing OSH. Figure 11B The diagram shows the inner conduit VIC in an expanded state, with the longitudinal protrusions LE contacting the inner surface of the outer casing OSH. This contact effectively prevents further expansion of the inner conduit VIC due to high internal pressure. Simultaneously, the area between two adjacent longitudinal protrusions LE does not contact the inner surface of the outer casing, thus providing space within the acoustic damping space ADD for the expansion and contraction of the inner conduit VIC to suppress pressure fluctuations within it.

[0095] exist Figure 10 , Figure 11A and Figure 11BIn this embodiment, protrusions and / or recesses in the outer surface of the inner catheter VIC are used to reduce the contact surface between the inner catheter VIC and the outer shell OSH. Due to the protrusions and / or recesses, a balance can be established between the contacts between the inner catheter VIC and the outer shell OSH to prevent further expansion of the entire inner catheter VIC, while still allowing local expansion and contraction of the inner catheter VIC to suppress pressure fluctuations.

[0096] The protrusions and / or recesses can be regular or irregular. The protrusions and / or recesses can extend in the circumferential direction, the longitudinal direction, or a combination of both, such as in a spiral shape.

[0097] In another embodiment, the inner catheter VIC may have a foam or foam-like outer layer configured to allow the viscoelastic material of the inner catheter VIC to expand and form an additional damping layer to suppress pressure fluctuations when the outer layer contacts the outer casing OSH. The foam or foam-like outer layer may be continuous, for example, co-extruded with the viscoelastic interior of the inner catheter, or formed into an annular protrusion pattern, such as... Figure 10 The examples are shown below. Examples of foam or foam-like materials are expanded or extruded polymer foams, such as polyurethane, polyolefins (e.g., LDPE, PP, PS), and elastomeric foams (e.g., EVA, NBR).

[0098] Alternatively or alternatively, protrusions and / or recesses and / or foam / foam-like layers may also be provided on the inner surface of the OSH housing, or provided by separate elements arranged in the acoustic damping space, such as cylindrical elements with protrusions and / or opening patterns.

[0099] In one embodiment, components for reducing contact between the outer surface of the inner catheter VIC and the inner surface of the outer casing OSH may include one or more restraining elements arranged to constrain the expansion of the inner catheter VIC. By providing restraining elements, the expansion of the inner catheter VIC can be locally constrained, for example by annular elements or longitudinal rod elements arranged on or within the wall of the inner catheter VIC. A series of annular elements placed on or within the wall of the inner catheter VIC can, for example, at least partially impede the expansion of the inner catheter VIC at the annular elements, while the inner catheter VIC can expand freely between two adjacent annular elements. As a result, an annular protrusion and recess pattern will be formed when the inner catheter VIC with annular restraining elements is exposed to increased pressure within the inner catheter VIC.

[0100] The protrusions can serve as contact surfaces between the inner conduit (VIC) and the outer casing (OSH) to limit the expansion of the inner conduit (VIC), while the recesses can still expand and contract locally to suppress pressure fluctuations in the liquid within the inner conduit (VIC). The restraining elements can also be arranged to limit the expansion of the inner conduit (VIC) so that the inner conduit does not contact the outer casing (OSH) during normal operation.

[0101] Similarly, when the internal catheter VIC expands, a constraining element (such as a helical constraining element) extending in the longitudinal direction or in both the longitudinal and circumferential directions can be used to create protrusion and recess patterns.

[0102] In another alternative embodiment, the components for reducing contact between the outer surface of the inner conduit VIC and the inner surface of the outer casing OSH include a pump device arranged to generate increased pressure in the acoustic damping space ADS. By increasing the pressure in the acoustic damping space ADS, the expansion of the inner conduit VIC can be at least partially offset.

[0103] Figure 12 Another embodiment of the acoustic damping device ADD is shown, wherein the housing is corrugated, and the corrugations of the housing are staggered, such that the inner surface of the housing is formed with a repeating pattern of a first corrugation 1COR and a second corrugation 2COR, wherein the first corrugation 1COR extends further into the acoustic damping space ADS than the second corrugation 2COR. Because the first corrugations 1COR extend further into the acoustic damping space ADS, these first corrugations 1COR can be used as contact surfaces to limit the maximum expansion of the inner conduit VIC. By providing the pattern of the first corrugations 1COR and the second corrugations 2COR, the pitch between the first corrugations 1COR can be selected so that the first corrugations 1COR can be used as contact surfaces, and between the first corrugations 1COR, where the second corrugations 2COR are provided, there is space for local expansion and contraction of the inner conduit VIC to suppress pressure fluctuations in the inner conduit VIC.

[0104] exist Figure 10 , Figure 11A , Figure 11B and Figure 12 In the illustrated embodiment, components are provided to reduce contact between the outer surface of the inner conduit VIC and the inner surface of the outer casing OSH when the inner conduit VIC expands due to internal pressure within the inner conduit VIC. These components can also be disposed in an acoustic damping device ADD having a casing without a flexibility portion OCS, i.e., without the feature that the casing has a main portion and a flexibility portion, wherein the flexibility portion has a first flexibility and the main portion has a second flexibility, wherein the first flexibility is greater than the second flexibility.

[0105] These embodiments can generally be described as a tubular acoustic damping device for use in a vacuum environment, the tubular acoustic damping device comprising:

[0106] The conduit includes an inner conduit made of viscoelastic material, having a first end to be connected to a liquid inlet and a second end to be connected to a liquid outlet.

[0107] The outer shell surrounding the inner conduit is made of an airtight material.

[0108] The annular damping space is formed between the inner duct and the outer shell.

[0109] The tubular acoustic damping device includes a component for reducing the contact between the outer surface of the inner conduit and the inner surface of the outer shell when the inner conduit expands due to the internal pressure in the inner conduit.

[0110] By providing a component that reduces the contact between the outer surface of the inner conduit and the inner surface of the outer shell, the contact surface area and / or location of this contact, such as the pitch of the repeating contact surfaces, can be controlled. This helps to strike a balance between providing a contact surface area between the outer surface of the inner conduit (VIC) and the inner surface of the outer shell (OSH) to limit the expansion of the inner conduit (VIC) and providing a sufficiently flexible inner conduit (VIC) to suppress pressure fluctuations. The component for reducing the contact between the outer surface of the inner conduit and the inner surface of the outer shell can also provide an outer shell (OSH) with a relatively small diameter, thereby reducing the overall volume of the tubular acoustic damping device while still providing a sufficiently flexible inner conduit (VIC) to suppress pressure fluctuations.

[0111] Figure 13 An example of an embodiment of an acoustic damping device (ADD) without a compliance component is shown. Corresponding to Figure 10 The acoustic damping device ADD has an annular protrusion RSE pattern on the outer surface of the inner conduit VIC.

[0112] Furthermore, in all the above embodiments, a single internal catheter (VIC) is provided within the housing OSH. In alternative embodiments, multiple internal catheters (VICs) may be provided within a single housing OSH.

[0113] While this article can specifically mention the use of photolithography equipment in IC manufacturing, it should be understood that the photolithography equipment described herein can have other applications. Other potential applications include the fabrication of integrated optical systems, the guiding and detection of patterns in magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0114] While embodiments of the invention may be specifically referred to herein in the context of lithography equipment, these embodiments can also be used with other equipment. Embodiments of the invention may form part of mask inspection equipment, metrology equipment, or any equipment for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning devices). These devices are generally referred to as lithography tools. Such lithography tools may use vacuum conditions or ambient (non-vacuum) conditions.

[0115] Although the above text may specifically mention the use of embodiments of the present invention in the context of optical lithography, it should be understood that, where the context permits, the present invention is not limited to optical lithography and may also be used in other applications, such as imprint lithography.

[0116] While specific embodiments of the invention have been described above, it should be understood that the invention can be practiced in ways other than those described. The foregoing description is intended to illustrate and not limit. Therefore, those skilled in the art will understand that modifications can be made to the invention without departing from the scope of the following claims.

Claims

1. A tubular acoustic damping device for use in a vacuum environment, comprising: The conduit comprises an inner conduit made of viscoelastic material, the inner conduit having a first end to be connected to a liquid inlet and a second end to be connected to a liquid outlet. A housing, surrounding the inner conduit, is made of an airtight material. An annular damping space is formed between the inner conduit and the outer shell. The housing has a main portion and a flexible portion, wherein the flexible portion has a first flexible amount and the main portion has a second flexible amount, wherein the first flexible amount is greater than the second flexible amount.

2. The tubular acoustic damping device according to claim 1, wherein the tubular acoustic damping device includes a longitudinal axis parallel to the central axis of the housing, and wherein the first flexibility is disposed in the direction of the longitudinal axis.

3. The tubular acoustic damping device according to claim 1 or 2, wherein the flexibility portion has an expandable volume depending on the internal pressure in the flexibility portion.

4. The tubular acoustic damping device according to any one of claims 1 to 3, wherein the compliance portion defines an annular compliance space having an open end connected to the annular damping space and a closed end opposite to the open end.

5. The tubular acoustic damping device according to claim 4, wherein the annular flexibility space is capable of expanding through a variable gap between the open end and the closed end.

6. The tubular acoustic damping device according to claim 4 or 5, wherein the flexibility portion comprises a tubular inner wall and a tubular outer wall, the tubular outer wall surrounding the tubular inner wall and coaxial with the tubular inner wall, the tubular inner wall and the tubular outer wall defining the annular flexibility space.

7. The tubular acoustic damping device of claim 6, wherein the tubular inner wall and the tubular outer wall are each corrugated to allow the inner tubular inner wall and the tubular outer wall to extend in a direction parallel to the central axis of the inner tubular wall and the outer tubular wall.

8. The tubular acoustic damping device according to any one of claims 1 to 6, wherein the viscoelastic material comprises at least one of the following: - Polytetrafluoroethylene, - Polyurethane, - Including terpolymers of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and - Fluororubber.

9. The tubular acoustic damping device according to any one of claims 1 to 8, wherein the housing is made of metal.

10. The tubular acoustic damping device according to any one of claims 1 to 9, wherein the housing is made of stainless steel.

11. The tubular acoustic damping device according to any one of claims 1 to 10, wherein the inner conduit is coated with a coating, wherein the coating is made of a metal, a watertight polymer, or a combination thereof.

12. The tubular acoustic damping device according to any one of claims 1 to 11, wherein the superabsorbent material for the coolant is arranged in the annular damping space formed between the inner conduit and the outer shell.

13. The tubular acoustic damping device according to any one of claims 1 to 12, wherein the tubular acoustic damping device comprises: A component for reducing contact between the outer surface of the inner conduit and the inner surface of the outer casing when the inner conduit expands due to internal pressure within the inner conduit.

14. The tubular acoustic damping device of claim 13, wherein the component for reducing contact between the outer surface of the inner conduit and the inner surface of the housing comprises a protrusion and / or recess pattern on the outer surface of the inner conduit.

15. The tubular acoustic damping device according to claim 14, wherein the protrusion and / or recess pattern comprises protrusions and / or recesses extending in the longitudinal and / or circumferential directions of the inner conduit.

16. The tubular acoustic damping device according to claim 14 or 15, wherein the pattern of protrusions and / or recesses comprises alternating annular protrusions and / or recesses.

17. The tubular acoustic damping device of claim 16, wherein the housing is corrugated, and wherein the corrugations of the housing have a first pitch, wherein the alternating annular protrusions and / or recesses have a second pitch, and wherein the second pitch is greater than the first pitch.

18. The tubular acoustic damping device according to claim 13, wherein the inner conduit has a foam or foam-like outer layer.

19. The tubular acoustic damping device of claim 13, wherein the component for reducing contact between the outer surface of the inner conduit and the inner surface of the housing comprises one or more restraining elements configured to constrain the expansion of the inner conduit.

20. The tubular acoustic damping device of claim 13, wherein the component for reducing contact between the outer surface of the inner conduit and the inner surface of the housing comprises a pump element arranged to generate increased pressure in the acoustic damping space.

21. The tubular acoustic damping device according to any one of claims 1 to 20, wherein the housing is corrugated, and wherein the corrugations of the housing are staggered, such that the inner surface of the housing is formed with a repeating pattern of a first corrugation and a second corrugation, wherein the first corrugation extends further into the acoustic damping space than the second corrugation.

22. A fluid delivery system for use in a vacuum environment, comprising: The tubular acoustic damping device according to any one of the preceding claims A first liquid line having a liquid outlet, wherein the first end of the inner conduit is connected to the liquid outlet. A second liquid line having a liquid inlet, wherein the first end of the inner conduit is connected to the liquid inlet.

23. A cooling system for cooling an object, the cooling system comprising the fluid delivery system according to the preceding claim.

24. A photolithography apparatus, comprising a cooling system according to the preceding claim, the cooling system being used to cool optical elements of a projection system of the photolithography apparatus.

25. The lithography apparatus of claim 24, wherein the first liquid line is mounted on a first frame of the lithography apparatus, and the second liquid line is mounted on a second frame of the lithography apparatus.

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