Directional gas purge for reducing dust accumulation on a window of an excimer discharge chamber

Abstract

A light source apparatus includes a chamber and a metal fluoride trap coupled to the chamber and configured to provide a cleaning gas to a set of window enclosure apparatuses coupled with the chamber. Each window enclosure apparatus is configured to reduce metal fluoride dusting on an optical window and includes a window enclosure supporting the optical window, an aperture apparatus coupled with the window enclosure, and an insert disposed between the aperture apparatus and the optical window. The aperture apparatus includes a plurality of cells configured to trap metal fluoride dust flowing upstream from the chamber through the aperture apparatus toward the optical window. The insert is configured to control a first flow rate of the cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture apparatus.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Application No. 62 / 951,860, filed December 20, 2019, entitled “DIRECTED GAS PURGE TO REDUCEDUSTING OF EXCIMER DISCHARGE CHAMBER WINDOWS”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to window housing devices and systems, such as window housing devices and systems for reducing metal fluoride dust accumulation. Background Technology

[0004] A photolithography apparatus is a machine configured to apply a desired pattern onto a substrate. Photolithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A photolithography apparatus can project a pattern from a patterning apparatus (e.g., a mask, a photomask) onto a layer of radiation-sensitive material (photoresist, or simply "resist") provided 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. Photolithography equipment using deep ultraviolet (DUV) radiation with wavelengths in the range of 20 nm to 400 nm, such as 193 nm or 248 nm, can be used to form features on a substrate.

[0006] The master oscillator power amplifier (MOPA) or master oscillator power ring amplifier (MOPRA) is a two-stage optical resonator arrangement that generates a highly coherent amplified beam. The performance of the MOPA or MOPRA is critically related to the master oscillator (MO), power amplifier (PA), and / or power ring amplifier (PRA). Electrodes surrounding the MO, PA, and / or PRA in the gas discharge medium can degrade over time, generating metal fluoride dust. This metal fluoride dust can deposit on the optical windows of the MO, PA, and / or PRA and can cause optical damage. Since the beam flux is higher in the PA or PRA (but not the MO), metal fluoride dust can lead to earlier optical damage to the PA or PRA over time. Furthermore, cycling of metal fluoride dust in the MO, PA, and / or PRA can also lead to reduced electrode discharge voltage and poor laser performance. Summary of the Invention

[0007] Therefore, it is necessary to reduce metal fluoride dust accumulation on the optical window, improve the control of the flow distribution through the window housing device, provide effective purging without increasing the clean gas return rate from the metal fluoride trap, and increase the service life of both the metal fluoride trap and the main oscillator.

[0008] In some embodiments, the light source device includes a chamber, a metal fluoride trap, and a set of window housing devices. The chamber is configured to hold a gas discharge medium from which a light beam is output. The metal fluoride trap is coupled to the chamber and configured to trap metal fluoride dust generated from the chamber and to provide clean gas, i.e., gas substantially free of fluoride dust, along its output port. A set of window housing devices is coupled to the chamber and configured to reduce metal fluoride dust accumulation on the optical window. Each window housing device includes a window housing, an aperture device, and an insert. The window housing supports the optical window. The aperture device is coupled to the window housing and includes multiple units configured to trap metal fluoride dust flowing upstream from the chamber through the aperture device toward the optical window. The insert is disposed between the aperture device and the optical window. The insert is configured to control a first flow rate of the clean gas along the optical window and a second flow rate of the clean gas through the aperture device.

[0009] In some embodiments, the insert is configured such that a first flow velocity along the optical window is greater than or equal to a second flow velocity through the aperture device. In some embodiments, the insert includes a channel configured to reduce the first flow velocity along the optical window and increase the second flow velocity through the aperture device. In some embodiments, the cross-sectional area of ​​the channel is proportional to the reduction in the first flow velocity and the increase in the second flow velocity.

[0010] In some embodiments, the window housing device further includes a plug having an orifice disposed between the inlet port of the window housing and the outlet port of the metal fluoride trap. In some embodiments, the plug and the outlet port are disposed within the frame of the chamber. In some embodiments, the orifice includes a diameter configured to control the flow rate of cleaning gas entering the window housing device.

[0011] In some embodiments, a plurality of shanks are disposed on the outer surface of the aperture device and configured to guide cleaning gas to flow around the aperture device toward the insert. In some embodiments, the outer diameter of the plurality of shanks is larger than the outer surface of the aperture device to provide clearance for the cleaning gas to flow through.

[0012] In some embodiments, the window housing includes a channel configured to flush cleaning gas along the optical window. In some embodiments, the window housing includes a Fresnel beam-catching recess configured to capture and absorb Fresnel reflections from the optical window to achieve a desired reflectance-transmittance ratio for the optical window.

[0013] In some embodiments, the gas discharge medium comprises an excimer and / or an excitation complex. In some embodiments, the gas discharge medium comprises F2, ArF, KrF, and / or XeF.

[0014] In some embodiments, the light source device further includes a set of optical elements configured to form an optical resonator around the chamber. In some embodiments, the set of optical elements includes an optical coupler for optical communication with a first window housing device and a linewidth narrowing module for optical communication with a second window housing device. In some embodiments, the set of optical elements includes a wavefront engineering box for optical communication with the first window housing device and a beam inverter for optical communication with the second window housing device.

[0015] In some embodiments, the insert is configured such that a first flow rate of cleaning gas along the optical window is configured to reduce the thermal boundary layer along the inner surface of the optical window.

[0016] In some embodiments, a window housing device configured to reduce metal fluoride dust accumulation on an optical window includes a window housing, an aperture device, and an insert. The window housing supports the optical window. The aperture device is coupled to the window housing and includes a plurality of units configured to capture metal fluoride dust flowing through the aperture device toward the optical window. The insert is disposed between the aperture device and the optical window. The insert is configured to control a first flow rate of cleaning gas along the optical window and a second flow rate of cleaning gas through the aperture device.

[0017] In some embodiments, the window housing includes an aperture configured to receive an aperture device and an insert. In some embodiments, the aperture includes undercuts and / or recesses configured to increase the volume of cleaning gas in the window housing device. In some embodiments, the window housing includes a channel configured to guide the cleaning gas along the optical window before it flows through the aperture device.

[0018] In some embodiments, a plurality of prongs are disposed along the outer surface of the aperture device and configured to guide cleaning gas to flow around the aperture device toward the insert. In some embodiments, the plurality of prongs are arranged symmetrically. In some embodiments, the plurality of prongs of the aperture device mechanically engage with a plurality of recesses in the insert.

[0019] In some embodiments, the aperture device includes a plurality of units, each configured to capture metal fluoride dust flowing upstream from the chamber through the aperture device toward an optical window. In some embodiments, the aperture device includes at least five units whose diameter decreases from the front end to the rear end toward the chamber.

[0020] In some embodiments, the window housing device is configured such that a first flow velocity along the optical window is greater than or equal to a second flow velocity through the aperture device.

[0021] In some embodiments, the insert includes a channel configured to reduce a first flow velocity along the optical window and increase a second flow velocity through the aperture device. In some embodiments, the cross-sectional area of ​​the channel is proportional to the reduction in the first flow velocity and the increase in the second flow velocity.

[0022] In some embodiments, a method for reducing metal fluoride dust accumulation on an optical window in a window housing device includes: guiding a cleaning gas from a metal fluoride trap to flow through an input port of the window housing device. In some embodiments, the method further includes guiding the cleaning gas to flow around an aperture device disposed in the window housing of the window housing device and toward an insert disposed between the aperture device and the optical window. In some embodiments, the method further includes: guiding the cleaning gas to flow through a channel in the window housing and along the inner surface of the optical window. In some embodiments, the method further includes guiding the cleaning gas from the optical window to flow through the aperture device.

[0023] In some embodiments, guiding the flow of cleaning gas from the metal fluoride trap includes guiding the cleaning gas flow through an orifice of a plug disposed between the input port and the output port of the metal fluoride trap. In some embodiments, the diameter of the orifice is configured to control the flow rate of the cleaning gas entering the window housing device.

[0024] In some embodiments, guiding the flow of cleaning gas around the aperture device includes guiding the flow of cleaning gas through a plurality of shanks disposed on the outer surface of the aperture device.

[0025] In some embodiments, guiding the flow of cleaning gas around the aperture device includes guiding the flow of cleaning gas through a channel in the insert.

[0026] In some embodiments, guiding the flow of cleaning gas through the channel includes guiding the cleaning gas from the channel to flow along the entire inner surface of the optical window.

[0027] In some embodiments, guiding the cleaning gas to flow from the optical window includes guiding the cleaning gas to flow from the inner surface of the optical window toward the aperture device and through a plurality of units with decreasing diameter from the front end to the rear end of the aperture device.

[0028] In some embodiments, the optical window forms part of a chamber configured to hold a gas discharge medium for the output beam, and further includes causing the gas discharge medium to generate the beam.

[0029] Implementations of any of the above technologies may include DUV light sources, systems, methods, processes, apparatuses, and / or devices. Details of one or more implementations are set forth in the accompanying drawings and the following description. Other features will be apparent from the specification, drawings, and claims.

[0030] Other features and exemplary aspects of the embodiments, as well as the structure and operation of various embodiments, are described in detail below with reference to the accompanying drawings. Note that the embodiments are not limited to the specific embodiments described herein. The embodiments presented herein are for illustrative purposes only. Additional embodiments will be apparent to those skilled in the art based on the teachings contained herein. Attached Figure Description

[0031] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments and, together with the specification, further serve to explain the principles of the embodiments and enable those skilled in the art to make and use these embodiments.

[0032] Figure 1A This is a schematic diagram of a reflective lithography apparatus according to an exemplary embodiment.

[0033] Figure 1B This is a schematic diagram of a transmission lithography apparatus according to an exemplary embodiment.

[0034] Figure 2 This is a schematic diagram of a light source device according to an exemplary embodiment.

[0035] Figure 3 This is based on an exemplary embodiment. Figure 2 The diagram shows a schematic cross-sectional view of the window housing device.

[0036] Figure 4 This is based on an exemplary embodiment. Figure 3 The schematic perspective cross-sectional view of the window housing of the window housing device shown.

[0037] Figure 5 This is based on an exemplary embodiment. Figure 3 A schematic perspective view of the aperture device of the window housing device shown.

[0038] Figure 6 This is based on an exemplary embodiment. Figure 5 A schematic cross-sectional view of the aperture device shown.

[0039] Figure 7 This is based on an exemplary embodiment. Figure 3 A schematic perspective view of the insert of the window housing device shown.

[0040] Figure 8This is a schematic perspective view of an insert according to an exemplary embodiment.

[0041] Figure 9 This illustrates an exemplary embodiment. Figure 3 A schematic diagram of the flow distribution of the window housing device shown.

[0042] Figure 10 The illustration shows a flowchart for reducing metal fluoride dust accumulation according to an exemplary embodiment.

[0043] The features and exemplary aspects of the embodiments will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which the same reference numerals consistently identify corresponding elements. In the drawings, the same reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, generally, the leftmost numeral of the reference numerals identifies the drawing in which the reference numeral first appears. Unless otherwise stated, the drawings provided throughout this disclosure should not be construed as being drawn to scale. Detailed Implementation

[0044] This specification discloses one or more embodiments incorporating the features of the invention. The disclosed embodiments(s) are merely illustrative of the invention. The scope of the invention is not limited to the disclosed embodiments(s). The invention is defined by the appended claims.

[0045] The described embodiments and references to "an embodiment," "embodiment," "example embodiment," "exemplary embodiment," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include specific features, structures, or characteristics. Furthermore, these phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be understood that, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0046] This document may use spatially relative terms such as “below,” “lower,” “lower,” “above,” “upper,” “higher,” etc., to describe the relationship between one element or feature and another element or feature as shown in the figure. In addition to the orientations shown in the figure, the spatially relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein will be interpreted accordingly.

[0047] As used herein, the terms “approximately,” “substantially,” or “approximately” indicate the value of a given quantity that can vary based on a particular technique. Based on a particular technique, the terms “approximately,” “substantially,” or “approximately” may indicate the value of a given quantity that varies within, for example, 1-15% of the value (e.g., ±1%, ±2%, ±5%, ±10%, or ±15% of the value).

[0048] Embodiments of the present invention can be implemented in hardware, firmware, software, or any combination thereof. Embodiments of this disclosure can also be implemented as instructions stored on a machine-readable medium, which can be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a machine-readable (e.g., computing device) form. For example, a machine-readable medium can include read-only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagation signals (e.g., carrier waves, infrared signals, digital signals, etc.). Furthermore, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only, and such actions are actually generated by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc.

[0049] However, it is beneficial to provide an example environment in which embodiments of this disclosure can be implemented before describing these embodiments in more detail.

[0050] Example lithography system

[0051] Figure 1A and Figure 1BThese are schematic diagrams of lithography apparatus 100 and 100', respectively, which implement embodiments of the present invention. Lithography apparatus 100 and 100' each include: an irradiation system (irradiator) IL configured to modulate a radiation beam B (e.g., deep ultraviolet (DUV) radiation); a support structure (e.g., a mask stage) MT configured to support a patterning apparatus (e.g., a mask, stencil, or dynamic patterning apparatus) MA and connected to a first positioner PM configured to precisely position the patterning apparatus MA; and a substrate stage (e.g., a wafer stage) WT configured to hold a substrate (e.g., a wafer coated with photoresist) W and connected to a second positioner PW configured to precisely position the substrate W. Lithography apparatuses 100 and 100' also have a projection system PS configured to project a pattern imparted by the radiation beam B by the patterning apparatus MA onto a target portion (e.g., comprising one or more dies) C of the substrate W. In the lithography apparatus 100, the pattern forming apparatus MA and the projection system PS are reflective. In the lithography apparatus 100', the pattern forming apparatus MA and the projection system PS are transmissive.

[0052] The irradiation system IL may include various types of optical components for guiding, shaping, or controlling the radiation beam B, such as refractive, reflective, anti-refractive, magnetic, electromagnetic, electrostatic, or other types of optical components or any combination thereof.

[0053] The support structure MT holds the patterning apparatus MA in a manner that relates to the orientation of the patterning apparatus MA relative to the reference frame, the design of at least one of the lithography apparatuses 100 and 100', and other conditions (e.g., whether the patterning apparatus MA is held in a vacuum environment). The support structure MT can hold the patterning apparatus MA using mechanical, vacuum, electrostatic, or other clamping techniques. The support structure MT can be, for example, a frame or stage, which may be fixed or movable as needed. By using sensors, the support structure MT can ensure that the patterning apparatus MA is, for example, in a desired position relative to the projection system PS.

[0054] The term "patterning apparatus" MA should be interpreted broadly to refer to any apparatus that can be used to impart a pattern to a radiation beam B on its cross-section to create a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B may correspond to a specific functional layer in the apparatus created in the target portion C to form an integrated circuit.

[0055] The pattern forming apparatus MA can be transmissive (e.g., in...). Figure 1B In the lithography equipment 100') or reflective type (such as in Figure 1A(In the photolithography apparatus 100). Examples of pattern forming apparatus MA include photomasks, masks, programmable mirror arrays, or programmable LCD panels. Masks are well known in photolithography and include mask types such as binary, alternating phase-shift, or attenuation phase-shift masks, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam B, which is reflected by the matrix of small mirrors.

[0056] The term "projection system" PS can encompass any type of projection system suitable for the exposure radiation used or for other factors (such as the use of an immersion liquid on a substrate W or the use of a vacuum), including refractive, reflective, antirefractive, magnetic, electromagnetic, and electrostatic optical systems or any combination thereof. A vacuum environment can be used for DUV or electron beam radiation because other gases can absorb excessive radiation or electrons. A vacuum environment can therefore be provided throughout the beam path by means of vacuum walls and a vacuum pump.

[0057] The lithography apparatus 100 and / or lithography apparatus 100' can be of the type having two (dual-stage) or more substrate stages WT (and / or two or more mask stages). In such a "multi-stage" machine, the additional substrate stages WT can be used in parallel, or preparation steps can be performed on one or more stages while one or more other substrate stages WT are used for exposure. In some cases, the additional stages may not be substrate stages WT.

[0058] Photolithography apparatuses can also be of the type in which at least a portion of the substrate can be covered by a liquid (e.g., water) with a relatively high refractive index to fill the space between the projection system and the substrate. Immersion liquids can also be applied to other spaces within the photolithography apparatus, such as the space between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. The term "immersion" as used herein does not imply that structures such as the substrate must be submerged in the liquid, but simply that the liquid is located between the projection system and the substrate during exposure.

[0059] refer to Figure 1A and Figure 1B The irradiator IL receives the radiation beam from the radiation source SO. For example, when the source SO is an excimer laser (e.g., a master oscillator power amplifier (MOPA) or a master oscillator power ring amplifier (MOPRA)), the source SO and the lithography apparatus 100, 100' can be separate physical entities. In this case, the source SO is not considered to form part of the lithography apparatus 100 or 100', and the radiation beam B is transmitted by means of a beam transmission system BD including, for example, suitable directional mirrors and / or beam expanders (in... Figure 1B(In the middle) the light is transmitted from the source SO to the irradiator IL. In other cases, such as when the source SO is a mercury lamp, the source SO can be an integral part of the lithography apparatus 100, 100'. If desired, the source SO, the irradiator IL, and the beam transmission system BD can be referred to as the radiation system.

[0060] The irradiator IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam (in Figure 1B (In the middle). Typically, at least the outer and / or inner radial ranges of the intensity distribution in the pupil plane of the irradiator can be adjusted (often referred to as "σ-outer" and "σ-inner," respectively). Additionally, the irradiator IL may include various other components (in Figure 1B In the middle, such as integrator IN and concentrator CO. Irradiator IL can be used to adjust the radiation beam B to have the desired uniformity and intensity distribution in its cross section.

[0061] refer to Figure 1A A radiation beam B is incident on a patterning apparatus (e.g., a mask) MA held on a support structure (e.g., a mask stage) MT and patterned by the patterning apparatus MA. In the lithography apparatus 100, the radiation beam B is reflected from the patterning apparatus (e.g., the mask) MA. After reflection from the patterning apparatus (e.g., the mask) MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. The substrate stage WT can be precisely moved (e.g., to position different target portions C in the path of the radiation beam B) using a second positioner PW and a position sensor IF2 (e.g., an interferometer, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor IF1 can be used to precisely position the patterning apparatus (e.g., the mask) MA relative to the path of the radiation beam B. The patterning apparatus (e.g., the mask) MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0062] refer to Figure 1B A radiation beam B is incident on a patterning apparatus (e.g., a mask MA) held on a support structure (e.g., a mask stage MT) and patterned by the patterning apparatus. After passing through the mask MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam onto a target portion C of the substrate W. The projection system has a pupil PPU conjugate with the illumination system pupil IPU. Part of the radiation is emitted from the intensity distribution at the illumination system pupil IPU and passes through the mask pattern unaffected by diffraction at the mask pattern, creating an intensity distribution image at the illumination system pupil IPU.

[0063] The projection system PS projects an image MP' of a mask pattern MP onto a photoresist layer coated on a substrate W, wherein the image MP' is formed by a diffracted beam generated from radiation from the marked pattern MP through an intensity distribution. For example, the mask pattern MP may comprise an array of lines and spacings. Radiation diffraction at the array, distinct from zero-order diffraction, generates a diffracted beam with a directional change in a direction perpendicular to the lines. The undiffracted beam (i.e., the so-called zero-order diffracted beam) passes through the pattern without any change in its propagation direction. The zero-order diffracted beam passes upstream of the pupil conjugate PPU of the projection system PS through the upper lens or upper lens group of the projection system PS, reaching the pupil conjugate PPU. The intensity distribution portion in the plane of the pupil conjugate PPU and associated with the zero-order diffracted beam is the intensity distribution image in the illumination system pupil IPU of the illumination system IL. An aperture device PD is, for example, positioned or substantially positioned at the plane comprising the pupil conjugate PPU of the projection system PS.

[0064] The projection system PS is arranged to capture not only the zeroth-order diffracted beam but also first-order or higher-order diffracted beams (not shown) via an upper lens or upper lens group L1 and a lower lens or lower lens group L2. In some embodiments, dipole illumination for imaging a line pattern extending in a direction perpendicular to the line can be used to utilize the resolution enhancement effect of dipole illumination. For example, a first-order diffracted beam interferes with the corresponding zeroth-order diffracted beam at the level of the wafer W, thereby creating an image MP' of the line pattern MP at the highest possible resolution and process window (i.e., the available depth of focus combined with tolerable exposure dose deviation). In some embodiments, astigmatism can be reduced by providing a radiating pole (not shown) in the opposing quadrant of the illumination system pupil IPU. For example, illumination at the illumination system pupil IPU can use only two opposing illumination quadrants, sometimes referred to as BMW illumination, such that the remaining two quadrants are not used for illumination but are configured to capture the first-order diffracted beam. Furthermore, in some embodiments, astigmatism can be reduced by blocking the zeroth-order beam associated with the radiating pole in the opposing quadrant of the projection system pupil conjugate PPU.

[0065] With the aid of a second positioner PW and a position sensor IF (e.g., an interferometer, linear encoder, or capacitive sensor), the substrate stage WT can be precisely moved (e.g., to position different target portions C within the path of the radiation beam B). Similarly, the first positioner PM and another position sensor ( Figure 1B (Not shown) can be used to precisely position the path of the mask MA relative to the radiation beam B (e.g., after mechanical acquisition from the mask library or during scanning).

[0066] Typically, the movement of the mask stage MT can be achieved using long-stroke modules (coarse positioning) and short-stroke modules (precise positioning), which form part of the first positioner PM. Similarly, the movement of the substrate stage WT can be achieved using long-stroke modules and short-stroke modules, which form part of the second positioner PW. In the case of a stepper (opposite to a scanner), the mask stage MT can be connected only to the short-stroke actuator or can be fixed. The mask MA and substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks (as shown) occupy dedicated target portions, they can be located in the space between the target portions (referred to as scribing alignment marks). Similarly, when more than one die is provided on the mask MA, the mask alignment marks can be located between the dies.

[0067] The mask stage MT and pattern forming apparatus MA can be located within a vacuum chamber V, where an IVR (Indoor Vacuum Robot) can be used to move the pattern forming apparatus, such as the mask, into and out of the vacuum chamber. Alternatively, when the mask stage MT and pattern forming apparatus MA are outside the vacuum chamber, an external vacuum robot, similar to an internal vacuum robot IVR, can be used for various transport operations. Both the internal and external vacuum robots need to be calibrated to smoothly transfer any payload (e.g., the mask) to a fixed motion support at the transport station.

[0068] Photolithography equipment 100 and 100' can be used in at least one of the following modes:

[0069] 1. In step mode, the support structure (e.g., mask stage) MT and substrate stage WT remain substantially stationary, while the entire pattern imparting the radiation beam B is projected onto the target portion C in one pass (i.e., single static exposure). The substrate stage WT then moves in the X and / or Y directions so that different target portions C can be exposed.

[0070] 2. In the scanning mode, while the pattern imparted to the radiation beam B is projected onto the target portion C, the support structure (e.g., mask stage) MT and the substrate stage WT are scanned simultaneously (i.e., single dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure (e.g., mask stage) MT can be determined by the (reduced) magnification and image inversion characteristics of the projection system PS.

[0071] 3. In another mode, the support structure (e.g., mask stage) MT of the programmable patterning apparatus remains substantially stationary, and the substrate stage WT is moved or scanned while the pattern imparted by the radiation beam B is projected onto the target portion C. A pulsed radiation source SO can be used, and the programmable patterning apparatus is updated as needed after each movement of the substrate stage WT or between successive radiation pulses during scanning. This operating mode can be readily applied to maskless lithography utilizing programmable patterning apparatuses such as programmable mirror arrays.

[0072] Alternatively, the described usage pattern or a combination and / or variation of completely different usage patterns may be adopted.

[0073] In another embodiment, the lithography apparatus 100 includes an extreme ultraviolet (EUV) radiation source configured to generate an EUV radiation beam for EUV lithography.

[0074] A relative vacuum, i.e., a small amount of gas (e.g., hydrogen) at a pressure much lower than atmospheric pressure, can be provided in the radiation source SO, the irradiation system IL, and / or the projection system PS. The radiation source SO can be a laser-generated plasma (LPP) source, a discharge-generated plasma (DPP) source, a free-electron laser (FEL), an excimer laser, a master oscillator power amplifier (MOPA), a master oscillator power ring amplifier (MOPRA), or any other radiation source capable of generating DUV radiation.

[0075] Exemplary light source device

[0076] As described above, a master oscillator power amplifier (MOPA) or master oscillator power ring amplifier (MOPRA) is a two-stage optical resonator arrangement. The master oscillator (MO) (e.g., a first optical resonator stage) generates a highly coherent beam. The power amplifier (PA) or power ring amplifier (PRA) (e.g., a second optical resonator stage) increases the optical power of the beam while maintaining the beam properties. The MO may include a gas discharge chamber, an optical coupler (OC), and a linewidth narrowing module (LNM). The OC and LNM may form an optical resonator around the gas discharge chamber. The PA or PRA may include a second gas discharge chamber, a wavefront engineering box (WEB), and a beam inverter (BR). The WEB and BR may form a second optical resonator around the second gas discharge chamber. For example, certain MOPAs and MOPRAs have been previously described in U.S. Patent No. 7,643,528, published January 5, 2010, and U.S. Patent No. 7,822,092, published October 26, 2010, the entire contents of which are incorporated herein by reference.

[0077] The performance of an MOPA or MOPRA can critically depend on the MO, PA, and / or PRA (e.g., the optical windows of the MO, PA, and / or PRA for output beams). Excimer lasers utilize excimers (e.g., excited dimers) or excitation complexes (e.g., excited complexes) to output deep ultraviolet (DUV) radiation. An excimer is a short-lived homodimer molecule formed from two substances (e.g., Ar2, Kr2, F2, Xe2). An excitation complex is a heterodimer molecule formed from more than two species (e.g., ArF, KrCl, KrF, XeBr, CeCl, XeF). Electrodes of the MO, PA, and / or PRA surrounding the gas discharge medium (e.g., F2, ArF, KrF, and / or XeF) may degrade over time and generate metal fluoride dust (e.g., with an average diameter of approximately 2.0 μm). Metal fluoride dust can deposit on the optical windows of the MO, PA, and / or PRA and can cause optical damage (e.g., localized thermal absorption and / or heating). Furthermore, the cycling of metal fluoride dust in MO can also lead to a decrease in discharge voltage from the electrodes and poor laser performance.

[0078] In some embodiments, the metal fluoride trap (MFT) may be coupled to the chamber of the MO and to the chambers of the PA and / or PRA to reduce contamination in the gas discharge medium. For example, certain MFTs have been previously described in U.S. Patent No. 6,240,117, published May 29, 2001, and U.S. Patent No. 7,819,945, published October 26, 2010, the entire contents of which are incorporated herein by reference. As a portion of the gas discharge medium passes through the MFT, metal fluoride dust in the contaminated gas discharge medium is adsorbed into the trap filter, and any remaining particles are collected by an electrostatic precipitator. The electrostatic precipitator induces the electrostatic charge in the dust particles to flow through the metal fluoride trap (MFT) via a strong electric field (e.g., an applied potential of several kV). For example, a voltage may be applied to a central conductor axially passing through the collection tube (e.g., cylindrical), creating electrostatic charge on the inner surface of the collection tube. Any residual metal fluoride dust adheres to the inner surface of the dust collection tube. The generated clean gas can be circulated back into the MO chamber, PA chamber, and / or PRA chamber through the disclosed optical window housing to keep the window dust-free.

[0079] However, in some embodiments, the MFT setup still fails to successfully eliminate metal fluoride dust and allow clean gas (e.g., dust-free) to flow back to the optical window housing. For example, thermal overload caused by metal fluoride dust accumulation on the optical window can lead to catastrophic slip planes (e.g., CaF2 crystal dislocations and / or plastic deformation) and may result in replacement of the MO, PA, and / or PRA chambers. Therefore, reducing metal fluoride dust accumulation on the optical window is critical, as even small amounts of dust accumulation can cause irreparable changes in the performance and lifespan of the MO, PA, and / or PRA chambers. Furthermore, simply increasing the clean gas (e.g., dust-free) flow rate from the MFT may not remedy the dust accumulation problem. By increasing the clean gas flow rate from the MFT (e.g., opening the input port), the MFT can accumulate metal fluoride dust at a rate much faster than the lifespan of the MO, PA, and / or PRA chambers, and thus can limit MFT functionality and overall light source lifespan. Specifically, the beam flux in the PA or PRA (but not the MO) is higher, and therefore, metal fluoride dust can cause earlier optical damage to the PA or PRA over time. Therefore, an appropriate balance must be struck between the clean gas recirculation rate (e.g., affecting MFT lifetime) and effectively purging the inner surfaces of the optical windows (e.g., exposed chambers) using the clean gas recirculation to reduce metal fluoride dust accumulation on the optical windows (e.g., affecting the lifetime of the MO chamber, PA chamber, and / or PRA chamber).

[0080] The embodiments of the light source devices and systems described below can reduce metal fluoride dust accumulation on optical windows, improve control over flow distribution through the window housing device, provide effective purification without increasing the clean gas return rate from the metal fluoride trap, and increase the lifespan of the metal fluoride trap and the master oscillator, power amplifier and / or power ring amplifier to, for example, provide an excimer laser beam (e.g., DUV radiation) to a DUV lithography device.

[0081] Figure 2 The illustration shows a light source device 200 according to various exemplary embodiments. The light source device 200 can be configured to: reduce metal fluoride dust contamination in a gas discharge stage 210 (e.g., MO, PA, PRA) and, for example, provide a highly coherent and aligned light beam (e.g., beam 202) to a DUV lithography apparatus (e.g., lithography apparatus 100'). The light source device 200 can be further configured to: reduce the accumulation of metal fluoride dust on a first window housing device 218 and a second window housing device 220, and increase the lifespan and laser performance of the gas discharge stage 210 (e.g., MO, PA, PRA) and / or the metal fluoride trap (MFT) 280. While the light source device 200 in… Figure 2While illustrated as a standalone device and / or system, embodiments of this disclosure can be used with other optical systems, such as, but not limited to, radiation source SO, lithography apparatus 100, 100', and / or other optical systems. In some embodiments, light source device 200 may be radiation source SO in lithography apparatus 100, 100'. For example, DUV radiation beam B may be beam 202. In some embodiments, light source device 200 may be a MOPA or MOPRA (not shown) formed by a gas discharge stage 210 (e.g., MO) and a second gas discharge stage (e.g., a PA and / or PRA similar to gas discharge stage 210). As described above, for example, certain MOPAs and MOPRAs have previously been described in U.S. Patent No. 7,643,528, published January 5, 2010, and U.S. Patent No. 7,822,092, published October 26, 2010, the entire contents of which are incorporated herein by reference.

[0082] like Figure 2 As shown, the light source device 200 may include a gas discharge stage 210, a voltage control system 230, a pressure control system 240, and an MFT 280. In some embodiments, all the components listed above may be housed in a three-dimensional (3D) frame 201. For example, the 3D frame 201 may include metal (e.g., aluminum, steel, etc.), ceramic, and / or any other suitable rigid material.

[0083] Gas discharge stage 210 can be configured to output a highly coherent beam (e.g., beam 202). Gas discharge stage 210 may include optical amplifier 206, a first optical module 250 (e.g., optical coupler (OC), wavefront engineering box (WEB)) and a second optical module 260 (e.g., linewidth narrowing module (LNM), beam reverser (BR)). In some embodiments, the first optical module 250 may include a first optical resonator element 252, and the second optical module 260 may include a second optical resonator element 262. Optical resonator 270 may be defined by the first optical module 250 (e.g., via the first optical resonator element 252) and the second optical module 260 (e.g., via the second optical resonator element 262). The first optical resonator element 252 may be partially reflective (e.g., a partial mirror), and the second optical resonator element 262 may be reflective (e.g., a mirror, grating, etc.) to form optical resonator 270. Optical resonator 270 can guide light generated by optical amplifier 206 (e.g., amplified spontaneous emission (ASE)) into optical amplifier 206 to form beam 202 through a fixed number of paths. In some embodiments, gas discharge stage 210 can output beam 202 to a PA stage (not shown) as part of an MOPA arrangement or a PRA stage (not shown) as part of an MOPRA arrangement. In some embodiments, gas discharge stage 210 can be, for example, an MO stage having OC and LNM. In some embodiments, gas discharge stage 210 can be, for example, a PA stage having WEB and BR. In some embodiments, gas discharge stage 210 can be, for example, a PRA stage having WEB and BR.

[0084] like Figure 2 As shown, the optical amplifier 206 may include a chamber 211, a first window housing device 218, and a second window housing device 220. The chamber 211 may be configured to hold a gas discharge medium 213 within the first window housing device 218 and the second window housing device 220. The chamber 211 may include an electrode 204, metal fluoride dust 208, a blower 212, the gas discharge medium 213, an input port 214 pointing to the MFT 280, a first output port 222 pointing to the first window housing device 218, and a second output port 224 pointing to the second window housing device 220. The input port 214 may be configured to transfer a portion of the gas discharge medium 213, along with the metal fluoride dust 208 in the chamber 211, into the MFT 280. The first output port 222 and the second output port 224 can be configured to transfer a portion of the gas discharge medium 213 (e.g., a cleaning gas for removing metal fluoride dust 208) from the MFT 280 through chamber 211 back to the first window housing device 218 and the second window housing device 220, respectively.

[0085] Optical amplifier 206 can be optically coupled to a first optical module 250 and a second optical module 260. Optical amplifier 206 can be configured to output amplified spontaneous emission (ASE) and / or beam 202. Beam 202 can be generated in a gas discharge medium 213 between electrodes 204 in a chamber 211 of an optical resonator 270 defined by the first optical module 250 and the second optical module 260. Chamber 211 can be coupled to MFT 280 and a first window housing device 218 and a second window housing device 220. Gas discharge medium 213 can be circulated between electrodes 204 in chamber 211 by a blower 212. In some embodiments, blower 212 can be a tangential blower. A portion of gas discharge medium 213 can be drawn at an input port 214 downstream of blower 212 and guided through MFT 280. Clean gases can be circulated back into chamber 211 via first window housing device 218 and second window housing device 220 to keep them free of laser debris (e.g., metal fluoride dust 208). In some embodiments, blower 212 and / or pressure control system 240 (e.g., vacuum line 244) can maintain the flow rate from chamber 211 into MFT 280 (e.g., input port 214) at approximately 100 sccm.

[0086] The gas discharge medium 213 can be configured to output an ASE and / or a beam 202 (e.g., 193 nm). In some embodiments, the gas discharge medium 213 may include a gas for excimer laser emission (e.g., Ar2, Kr2, F2, Xe2, ArF, KrCl, KrF, XeBr, XeCl, XeF, etc.). For example, the gas discharge medium 213 may include ArF and outputs the ASE and / or beam 202 (e.g., 193 nm) via a first window housing device 218 and a second window housing device 220 when excited (e.g., by applying a voltage) from the surrounding electrode 204 in chamber 211. In some embodiments, the gas discharge medium 213 may include an excimer and / or an excitation complex. For example, the gas discharge medium 213 may include F2, ArF, KrF, and / or XeF.

[0087] The first optical module 250 can be configured to optically communicate with the second window housing device 220. In some embodiments, the first optical module 250 can be configured to partially reflect a light beam and form part of an optical resonator 270. For example, the first optical module (e.g., OC, WEB) has previously been described in U.S. Patent No. 7,885,309, published February 8, 2011, and U.S. Patent No. 7,643,528, published January 5, 2010, which are incorporated herein by reference in their entirety. Figure 2As shown, the first optical module 250 may include a first optical resonator element 252 for directing light (e.g., ASE and / or beam 202) from the optical amplifier 206 back into the optical amplifier 206 and / or the output beam 202. In some embodiments, the first optical resonator element 252 may be adjusted (e.g., tilted).

[0088] The second optical module 260 can be configured to optically communicate with the first window housing device 218. In some embodiments, the second optical module 260 can be configured to provide spectral narrowing to the light beam and form part of an optical resonator 270. For example, second optical modules (e.g., LNM, BR) have been previously described in U.S. Patent No. 8,126,027, published February 28, 2012, and U.S. Patent No. 7,822,092, published October 26, 2010, the entire contents of which are incorporated herein by reference. Figure 2 As shown, the second optical module 260 may include a second optical resonator element 262 for directing light (e.g., ASE and / or beam 202) from the optical amplifier 206 back into the optical amplifier 206 towards the first optical module 250. In some embodiments, the second optical resonator element 262 may be adjusted (e.g., tilted, angled).

[0089] The voltage control system 230 can be configured to apply high-voltage electrical pulses across electrodes 204 in chamber 211 to excite the gas discharge medium 213 to output ASE and / or beam 202 (e.g., 193 nm). The voltage control system 230 may include a voltage supply line 232. In some embodiments, the voltage control system 230 may include a high-voltage power supply (not shown), a voltage compression amplifier (not shown), a pulse energy monitor (not shown), and / or a controller (not shown) for providing high-voltage electrical pulses across electrodes 204. For example, a voltage control system was previously described in U.S. Patent No. 6,240,117, published May 29, 2001, the entire contents of which are incorporated herein by reference.

[0090] Pressure control system 240 may be configured to control the fluorine concentration in chamber 211 and supply gas discharge medium 213 to chamber 211. Pressure control system 240 may include gas discharge line 242 and vacuum line 244. Gas discharge line 242 may be configured to supply one or more gaseous components (e.g., Ar2, Kr2, F2, Xe2, ArF, KrCl, KrF, XeBr, XeCl, XeF, KrNe, etc.) of gas discharge medium 213 to chamber 211. Vacuum line 244 may be configured to provide negative pressure (e.g., extraction) to a portion of gas discharge medium 213 in chamber 211, for example, during the injection of one or more gaseous components into gas discharge medium 213 via gas discharge line 242. In some embodiments, pressure control system 240 may include one or more gas sources (not shown) for controlling the fluorine concentration in chamber 211 and refilling gas discharge medium 213 in chamber 211, one or more pressure regulators (not shown), vacuum pump (not shown), fluorine (F2) trap, and / or controller (not shown). For example, a pressure control system has been described in U.S. Patent No. 6,240,117, published May 29, 2001, the entire contents of which are incorporated herein by reference. In some embodiments, the pressure control system 240 may be coupled to the gas discharge stage 210 and configured such that a portion of the gas discharge medium 213 having metal fluoride dust 208 flows through the input port 214 of the MFT 280, through the MFT 280 (e.g., a packed bed filter), and through the first and / or second output ports 222, 224 of the MFT 280.

[0091] In some embodiments, the MFT 280 may be configured to capture metal fluoride dust 208 generated in the gas discharge medium 213 within the chamber 211 of the gas discharge stage 210. The MFT 280 may be further configured to reduce the accumulation of metal fluoride dust 208 on the first window housing device 218 and the second window housing device 220, and to increase the lifespan and laser performance of the gas discharge stage 210 (e.g., MO, PA, PRA). In some embodiments, the MFT 280 may be located outside the 3D frame 201 of the light source device 200. For example, the MFT 280 may be connected to the chamber 211 via an input port 214 and a first output port 222 and a second output port 224, the first output port 222 and the second output port 224 being extended such that the MFT 280 is located outside the 3D frame 201.

[0092] In some embodiments, the MFT 280 may include an MFT frame 281, an input port 214 coupled to a chamber 211, a first output port 222 coupled to the chamber 211 and a first window housing device 218, and a second output port 224 coupled to the chamber 211 and a second window housing device 220. In some embodiments, the MFT frame 281 may be cylindrical. For example, the MFT frame 281 may be approximately 10 mm (diameter) by approximately 100 mm (length).

[0093] In some embodiments, input port 214 may be configured to deliver a portion of the gas discharge medium 213 containing metal fluoride powder 208 in chamber 211 to MFT 280. In some embodiments, the gas discharge medium 213 may flow through a metal fluoride dust collector (not shown) (e.g., a packed bed filter) and / or an electrostatic precipitator (not shown), and the metal fluoride dust 208 may be adsorbed in MFT 280. First output port 222 and second output port 224 may be configured to deliver a portion of the gas discharge medium 213 that has passed through chamber 211 and through MFT 280 (e.g., clean gas to remove metal fluoride dust 208) back to first window housing device 218 and second window housing device 220, respectively. In some embodiments, MFT 280 may include an electrostatic precipitator (not shown) configured to induce charge flow through the metal fluoride dust 208 in MFT 280 and promote the adsorption of remaining metal fluoride dust 208.

[0094] Exemplary window housing device

[0095] Figure 3 This is based on an exemplary embodiment. Figure 2 A schematic cross-sectional view of the window housing device 300 (e.g., the second window housing device 220) of the light source device 200 shown. Figure 4 This is based on an exemplary embodiment. Figure 3 A schematic perspective cross-sectional view of the window housing 400 of the window housing device 300 (e.g., the second window housing device 220) shown. Figure 5 This is based on an exemplary embodiment. Figure 3 A schematic perspective view of the aperture device 500 of the window housing device 300 (e.g., the second window housing device 220). Figure 7 This is based on an exemplary embodiment. Figure 3 A schematic perspective view of the insert 700 of the window housing device 300 (e.g., the second window housing device 220). Figure 9 This is based on an exemplary embodiment. Figure 3The schematic flow distribution of the window housing device 300 (e.g., the second window housing device 220) shown.

[0096] In some embodiments, the window housing device 300 (e.g., the second window housing device 220) can be configured to reduce metal fluoride dust accumulation on the optical window (e.g., optical window 228). The window housing device 300 can be further configured to capture metal fluoride dust and control a first flow rate of clean gas (e.g., dust-free) along the optical window (e.g., optical window 228) and a second flow rate of clean gas (e.g., dust-free) through an aperture device (e.g., aperture device 500). The window housing device 300 can be further configured to reduce the formation of thermal boundary layers (e.g., localized hot spots, thermal lenses, etc.) along the optical window (e.g., optical window 228).

[0097] In some embodiments, the window housing device 300 may be a first window housing device 218 and / or a second window housing device 220. For example, such as Figure 3 As shown, the window housing device 300 can be a second window housing device 220. In some embodiments, the first window housing device 218 and the second window housing device 220 can be similar (e.g., mirror-symmetric). For example, both the first window housing device 218 and the second window housing device 220 can be similar to the window housing device 300 (e.g., the second window housing device 220 can be the same as the window housing device 300, and the first window housing device 218 can be mirror-symmetric to the window housing device 300). Although the window housing device 300 is in Figure 3 While shown as a standalone device and / or system, embodiments of this disclosure may be used in conjunction with other optical systems, such as, but not limited to, radiation source SO, lithography apparatus 100, 100', light source apparatus 200, optical amplifier 206, chamber 211 and / or other optical systems.

[0098] In some embodiments, the window housing device 300 may be coupled to chamber 211 (e.g., via O-ring seal 420) and input port 227 to receive clean gas (e.g., dust-free and / or filtered gas) from MFT 280 along output port 224. In some embodiments, the window housing device 300 may include an optical window 228, a window housing 400, a plug 225, an aperture device 500, and an insert 700. In some embodiments, the window housing device 300 may extend into chamber 211. For example, as... Figure 3 As shown, the window housing device 300 (e.g., the rear end 502 of the aperture device 500) can extend into the interior of the chamber 211 through the optical port (e.g., the drill hole 219) of the chamber 211.

[0099] Optical window 228 may be a beam splitter (e.g., dichroic) configured to reflect and transmit the ASE and / or beam 202 from chamber 211. For example, as... Figure 3 As shown, the optical window 228 can be arranged in the window housing 400 at an incident angle (e.g., about 70 degrees) to guide (e.g., reflect) a portion of the ASE and / or beam 202 to the upper window housing 404 (e.g., upper Fresnel beam capturing recess 405) and to guide (e.g., transmit) a portion of the ASE and / or beam 202 toward the lower window housing 402 (e.g., lower Fresnel beam capturing recess 403).

[0100] Window housing 400 can be configured to support optical window 228. Window housing 400 can be further configured to flush cleaning gas along the inner surface 229 of optical window 228. Window housing 400 can be further configured to provide a desired reflectance-transmittance ratio for optical window 228 (e.g., via lower and upper Fresnel beam trapping recesses 403, 405). While window housing 400 (e.g., upper window housing 404) in Figure 4 While illustrated as a standalone device and / or system, embodiments of this disclosure can be used in conjunction with other optical systems, such as, but not limited to, radiation source SO, lithography apparatus 100, 100', light source apparatus 200, optical amplifier 206, chamber 211, window housing apparatus 300, first window housing apparatus 218, second window housing apparatus 220, and / or other optical systems. In some embodiments, window housing 400 may comprise metal (e.g., stainless steel, aluminum, etc.), ceramic, polymer, and / or any other suitable rigid material.

[0101] like Figure 3 and Figure 4As shown, in some embodiments, the window housing 400 may include a lower window housing 402 and an upper window housing 404. The lower window housing 402 and the upper window housing 404 may support and connect along the optical window 228. For example, the lower window housing 402, the upper window housing 404, and the optical window 228 may form a sealing assembly, for example, via a window O-ring seal and / or one or more fasteners. The lower window housing 402 may be configured to receive a light beam (e.g., beam 202) and transmit the beam into the window housing device 300 (e.g., to the upper window housing 404) and into the chamber 211. The lower window housing 402 may include a lower Fresnel beam-catching recess 403, configured to capture and absorb (e.g., multiple beam bounces) a portion of the light beam (e.g., ASE and / or beam 202) from the optical window 228 (e.g., from Fresnel reflection). The lower Fresnel beam-capturing recess 403 can be configured to capture and absorb Fresnel reflections from the optical window 228 to achieve a desired reflectance-transmittance ratio for the optical window 228. The lower window housing 402 can be separated from the chamber 211 and the metal fluoride dust 208 (e.g., fluidly) and therefore may not receive cleaning gas from the MFT 280. In some embodiments, the lower window housing 402 (e.g., the exterior) can be purged with a separate cleaning gas (e.g., N2).

[0102] The upper window housing 404 can be configured to receive a light beam (e.g., ASE and / or beam 202) and transmit the light beam out of the window housing device 300 (e.g., to the lower window housing 402) and out of the optical amplifier 206. The upper window housing 404 may include an upper Fresnel beam-catching recess 405, a housing aperture 406, a housing port 410, a housing channel 412, a housing D-slot 414, and a chamber O-ring seal 420. The upper Fresnel beam-catching recess 405 can be configured to capture and absorb (e.g., multiple beam bounces) a portion of the light beam (e.g., ASE and / or beam 202) from the optical window 228 (e.g., from Fresnel reflections). The upper Fresnel beam-catching recess 405 can be configured to capture and absorb Fresnel reflections from the optical window 228 to achieve a desired reflectance-transmittance ratio for the optical window 228. Figure 3As shown, the upper window housing 404 can be coupled to the chamber 211 (e.g., chamber frame 223 and borehole 219) via an O-ring seal 420. For example, the rear end 502 and input port 227 of the aperture device 500 can be disposed within the inner diameter of the O-ring seal 420 to fluidly seal the chamber 211 and output port 224 to the input port 227, the aperture device 500, and the window housing 400. In some embodiments, the O-ring seal 420 can be a metal (e.g., nickel plating, nickel, stainless steel, copper, aluminum, etc.). In some embodiments, the upper window housing 404 (e.g., the interior) can be purged with a clean gas (e.g., a gas substantially free of fluoride dust) from the MFT 280.

[0103] The housing bore 406 can be configured to receive the aperture device 500 (e.g., window portion 520) and the insert 700. The housing bore 406 may include a housing bore undercut 408, a housing recess 416, and a housing lip 418. The housing bore undercut 408 and / or the housing recess 416 can be configured to increase the volume of cleaning gas in the window housing device 300. For example, the outer diameter of the housing bore undercut 408 and / or the housing recess 416 may be larger than the outer diameter of the aperture device 500 and / or the insert 700 to guide the cleaning gas around the aperture device 500 and toward the insert 700. The housing recess 416 can be configured to form a tight fluid seal with the aperture device 500 (e.g., first shank 522 and third shank 526) and the insert 700. The housing lip 418 can be configured to form a tight fluid seal with the aperture device 500 (e.g., window portion 520) and the input port 227. The outer shell lip 418 may have a smaller diameter than the undercut of the outer shell hole 408.

[0104] The housing port 410, housing channel 412, and housing D-slot 414 can be configured to guide the flow of cleaning gas through the housing channel 412, into the housing port 410, along the inner surface 229 of the optical window 228, and toward the insert 700 and the aperture device 500. The housing channel 412 can be configured to flush the cleaning gas (e.g., dust-free) along the inner surface 229 of the optical window 228. The housing channel 412 can also be configured to guide the cleaning gas along the optical window 228 before flowing through the aperture device 500 and the insert 700. In some embodiments, the housing channel 412 and / or the housing port 410 can be configured to guide the cleaning gas from the housing channel 412 along the entire inner surface 229 of the optical window 228. The housing aperture 406 can be fluidly connected to the housing channel 412 and the housing port 410 (e.g., around the housing D-slot 414).

[0105] In some embodiments, the window housing device 300 may include a plug 225 having a hole 226. In some embodiments, the plug 225 may be disposed between an input port 227 and an output port 224. For example, as Figure 3 As shown, output port 224 may be disposed within chamber 211 (e.g., within chamber frame 223), and plug 225 may be disposed within output port 224. Plug 225 may comprise rubber, silicone, cork, and / or any other suitable material capable of preventing fluid flow between output port 224 and input port 227, other than through-hole 226. In some embodiments, plug 225 may be replaced and / or replaced with similar plugs having different orifice diameters (e.g., 70 mils to 50 mils, 60 mils to 100 mils, etc.) to control (e.g., increase or decrease) the flow rate of cleaning gas entering the window housing device 300 (e.g., 100 sccm).

[0106] Orifice 226 may be a through-hole for fluidly connecting the cleaning gas between output port 224 and input port 227 of window housing device 300. Orifice 226 may have a diameter configured to control the flow rate of the cleaning gas from MFT 280 to window housing device 300. For example, the diameter (d) of orifice 226 may be proportional to the flow rate of the cleaning gas entering input port 227 (e.g., d0). 4 (For example, a decrease in diameter is proportional to a decrease in flow rate (e.g., 16 times), and an increase in diameter is proportional to an increase in flow rate (e.g., 16 times)). In some embodiments, the diameter of the orifice 226 may be from about 50 mils (1.27 mm) to about 150 mils (3.81 mm), but other diameters are used in other embodiments. For example, the diameter of the orifice 226 may be about 70 mils (1.778 mm).

[0107] In some embodiments, the flow distribution of the clean gas from the MFT 280 travels along the output port (e.g., the first output port 222 and / or the second output port 224), through the hole 226 of the plug 225, through the input port 227, through the undercut of the housing hole 408, around the aperture device 500 (e.g., around the second outer surface 514 between the first and second prongs 522, 524 and the third prongs 526 and the fourth prongs 528), toward the insert 700, through the housing channel 412, through the housing port 410 and around the housing D-slot 414, through the insert 700 and through the aperture device 500.

[0108] Exemplary aperture device

[0109] Figure 5 This is based on an exemplary embodiment. Figure 3A schematic perspective view of the aperture device 500 of the window housing device 300 (e.g., the second window housing device 220). Figure 6 This is based on an exemplary embodiment. Figure 5 The diagram shows a schematic cross-sectional view of the aperture device 500.

[0110] The aperture device 500 can be configured to capture metal fluoride dust 208 flowing through the aperture device 500. Although the aperture device 500 is... Figure 5 and Figure 6 While shown as a standalone device and / or system, embodiments of this disclosure may be used in conjunction with other optical systems, such as, but not limited to, radiation source SO, lithography apparatus 100, 100', light source apparatus 200, optical amplifier 206, chamber 211, window housing apparatus 300, first window housing apparatus 218, second window housing apparatus 220, window housing 400 and / or other optical systems.

[0111] like Figure 5 and Figure 6 As shown, in some embodiments, the aperture device 500 may include a rear end 502, a front end 504, a chamber portion 510, a window portion 520, and a plurality of units 548, 558, 568, 578, and 588. The rear end 502 may face the chamber 211, and the front end 504 may face the optical window 228. The chamber portion 510 may be configured to extend into the chamber 211 (e.g., via a drilled hole 219 in the chamber frame 223). The chamber portion 510 may include a first outer surface 512 having a first diameter. In some embodiments, the aperture device 500 may include a metal (e.g., nickel plating, nickel, stainless steel, aluminum, etc.), ceramic, and / or any other suitable rigid material.

[0112] Window portion 520 may be configured to extend into window housing 400 (e.g., via housing aperture 406). Window portion 520 may include a second outer surface 514, the second diameter of which is larger than the first diameter of chamber portion 510. Window portion 520 may include a notch 516 and a plurality of shanks 522, 524, 526, 528. Notch 516 may be configured to provide window housing 400 and chamber frame 223 for input port 227.

[0113] Handles 522, 524, 526, and 528 can be configured to guide cleaning gas around the aperture device 500 (e.g., the second outer surface 514) toward the insert 700. Figure 5As shown, handles 522, 524, 526, and 528 can be disposed on the second outer surface 514. Handles 522, 524, 526, and 528 can have an outer diameter larger than the second outer surface 514 to provide a small gap for the cleaning gas to flow through toward the insertion port 720 of the insert 700. The first handle 522 and the second handle 524 can be separated from each other along the second outer surface 514, and the third handle 526 and the fourth handle 528 can be separated from each other along the second outer surface 514. In some embodiments, such as Figure 5 As shown, the first handle 522 and the second handle 524, as well as the third handle 526 and the fourth handle 528, can be arranged symmetrically (e.g., double symmetry, 180-degree rotation). In some embodiments, such as Figure 5 As shown, the first prong 522 and the third prong 526 may extend beyond the front end 504 (e.g., the first baffle 530) to couple to the insert 700 and / or the housing bore 406 (e.g., the housing recess 416). For example, the first prong 522 and the third prong 526 may be configured to mechanically engage with the recesses 712, 716 of the insert 700.

[0114] Units 548, 558, 568, 578, and 588 can be configured to capture metal fluoride dust 208 flowing upstream from chamber 211 through aperture device 500 (e.g., via baffles 530, 540, 550, 560, 570, 580, and / or the Venturi effect) toward optical window 228. Each unit 548, 558, 568, 578, and 588 can be configured to capture metal fluoride dust 208 flowing upstream from chamber 211 through aperture device 500 toward optical window 228 (e.g., downstream flow of cleaning gas is from front end 504 to rear end 502, and upstream flow of metal fluoride dust 208 from chamber 211 is from rear end 502 to front end 504). In some embodiments, units 548, 558, 568, 578, and 588 may have an outer diameter that decreases from front end 504 to rear end 502 toward chamber 211. For example, such as Figure 6 As shown, unit 548 may have a larger diameter than unit 558, unit 558 may have a larger diameter than unit 568, unit 568 may have a larger diameter than unit 578, and unit 578 may have a larger diameter than unit 588.

[0115] like Figure 6As shown, each unit 548, 558, 568, 578, 588 can be formed by corresponding baffles 530, 540, 550, 560, 570, 580. The first baffle 530 (e.g., at the front end 504) may include a first upper baffle 532, a first lower baffle 534, and a first aperture 536. The second baffle 540 may include a second upper baffle 542, a second lower baffle 544, and a second aperture 546. The third baffle 550 may include a third upper baffle 552, a third lower baffle 554, and a third aperture 556. The fourth baffle 560 may include a fourth upper baffle 562, a fourth lower baffle 564, and a fourth aperture 566. The fifth baffle 570 may include a fifth upper baffle 572, a fifth lower baffle 574, and a fifth aperture 576. The sixth baffle 580 (e.g., at the rear end 502) may include a sixth upper baffle 582, a sixth lower baffle 584, and a sixth aperture 586. A first unit 548 may be formed between the first baffle 530 and the second baffle 540, a second unit 558 may be formed between the second baffle 540 and the third baffle 550, a third unit 568 may be formed between the third baffle 550 and the fourth baffle 560, a fourth unit 578 may be formed between the fourth baffle 560 and the fifth baffle 570, and a fifth unit 588 may be formed between the fifth baffle 570 and the sixth baffle 580.

[0116] In some embodiments, apertures 536, 546, 556, 566, 576, and 586 may have the same diameter, while in other embodiments, they have different diameters. In some embodiments, one or more baffles 530, 540, 550, 560, 570, and 580 may be angled relative to the transverse axis of the aperture device 500. For example, as Figure 6 As shown, the first baffle 530 can be tilted toward the front end 504, and the sixth baffle 580 can be tilted toward the rear end 502.

[0117] Exemplary insert

[0118] Figure 7 and Figure 8 This is a schematic perspective view of inserts 700, 700' according to various exemplary embodiments. Figure 7 This is based on an exemplary embodiment. Figure 3 A schematic perspective view of the insert 700 of the window housing device 300 (e.g., the second window housing device 220).

[0119] The insert 700 can be configured to control a first flow rate of the cleaning gas along the optical window 228 and a second flow rate of the cleaning gas through the aperture device 500. The insert 700 can be positioned between the aperture device 500 and the optical window 228. In some embodiments, the first flow rate along the optical window 228 can be greater than or equal to the second flow rate through the aperture device 500. Although the insert 700 is in... Figure 7 While the embodiments of this disclosure are shown as standalone devices and / or systems, they can be used in conjunction with other optical systems, such as, but not limited to, radiation source SO, lithography apparatus 100, 100', light source apparatus 200, optical amplifier 206, chamber 211, window housing apparatus 300, first window housing apparatus 218, second window housing apparatus 220, window housing 400, aperture apparatus 500 and / or other optical systems.

[0120] like Figure 7 As shown, in some embodiments, the insert 700 may include a rear end 702, a front end 704, a first recess 712, a second recess 716, an insert port 720, and an insert aperture 730. The rear end 702 may face the aperture device 500 (e.g., the front end 504), and the front end 704 may face the optical window 228. The front end 704 may include a front surface 706. The insert 700 may have an outer diameter similar to that of the front end 504 of the aperture device 500. In some embodiments, the insert 700 may include a metal (e.g., nickel plating, nickel, stainless steel, aluminum, etc.), ceramic, and / or any other suitable rigid material.

[0121] The first and second recesses 712, 716 may be configured to mechanically engage with the first and third prongs 522, 526 of the aperture device 500 to fluidly seal the aperture device 500 and the insert 700 together. The insert port 720 may be configured to engage with the housing recess 416 and / or direct cleaning gas flow to the housing passage 412. The insert orifice 730 may be configured to direct cleaning gas flow through the aperture device 500 (e.g., the first baffle 530). In some embodiments, the insert port 720 may be similar to the first baffle 530 of the aperture device 500 (e.g., a rectangular orifice). For example, the diameter of the insert port 720 may be the same as that of orifices 536, 546, 556, 566, 576, 586.

[0122] Figure 8 This is a schematic perspective view of insert 700' according to an exemplary embodiment. Figure 7 The embodiment of the insert 700 shown is similar to Figure 8 The embodiment of the insert 700' shown may be similar. The same reference numerals are used to indicate... Figure 7 Similar features of the embodiment of the insert 700 shown and Figure 8 Similar features to the embodiment of the insert 700' shown. Figure 7 The embodiment of the insert 700 shown is similar to Figure 8 One difference between the embodiments of the insert 700' shown is that the insert 700' is on the front surface 706' (rather than) Figure 7 The front surface 706 of the insert 700 shown includes an insert channel 722, which is configured to guide a portion of the cleaning gas flow through the insert aperture 730 and reduce the first flow velocity along the inner surface 229 of the optical window 228.

[0123] like Figure 8 As shown, an exemplary aspect of the insert 700' is an insert channel 722, which is configured to guide a portion of the cleaning gas flow through the insert aperture 730 and, for example, to divert a portion of the cleaning gas flowing toward the housing channel 412, housing port 410, and optical window 228 to the insert aperture 730, thereby reducing a first flow velocity along the inner surface 229 of the optical window 228. In some embodiments, the insert channel 722 may be configured to reduce the first flow velocity along the optical window 228 and increase a second flow velocity through the aperture device 500. For example, the cross-sectional area (e.g., diameter d) of the insert channel 722 may be proportional to the reduction of the first flow velocity along the inner surface 229 of the optical window 228 and the increase of the second flow velocity entering the insert aperture 730 (e.g., d...). 4 (For example, the reduction in the diameter of the insert channel 722 is proportional to the reduction in the second flow rate entering the insert aperture 730 (e.g., 16 times) and proportional to the increase in the first flow rate along the inner surface 229 of the optical window 228 (e.g., 16 times)). Similarly, the increase in the diameter of the insert channel 722 is proportional to the reduction in the first flow rate along the inner surface 229 of the optical window 228 (e.g., sixteen times) and proportional to the increase in the second flow rate entering the insert aperture 730 (e.g., sixteen times). The insert channel 722 can convey a portion of the cleaning gas flowing to the housing channel 412, housing port 410, and optical window 228 to the insert aperture 730 and the first baffle 530 of the aperture device 500, and thus reduce the first flow rate to the optical window 228 and increase the second flow rate through the aperture device 500.

[0124] Exemplary Stream Distribution

[0125] Figure 9 This illustrates an exemplary embodiment. Figure 3 A schematic diagram of the flow distribution 900 of the shown window housing device 300 (e.g., the second window housing device 220). Figure 9As shown, the flow distribution 900 includes a first flow position 902 (e.g., input port 227), a second flow position 904 (e.g., undercut of housing aperture 408), a third flow position 906 (e.g., around window portion 520), a fourth flow position 908 (e.g., through housing channel 412), a fifth flow position 910 (e.g., through housing port 410 and along the inner surface 229 of optical window 228), and a sixth flow position 912 (e.g., through insert 700 and aperture device 500). The direction of the cleaning gas flow in the window housing device 300 (e.g., second window housing device 220) (e.g., flow distribution 900) follows the successive flow positions 902, 904, 906, 908, 910, and 912. In some embodiments, the flow distribution 900 extends along the entire inner surface 229 of optical window 228 to reduce metal fluoride dust on optical window 228.

[0126] In some embodiments, the flow distribution 900 in the window housing device 300 may be laminar or near-laminar. For example, the flow distribution 900 along the inner surface 229 of the optical window 228 may be laminar or near-laminar to disrupt any thermal boundary layer formed on the inner surface 229. In some embodiments, the flow distribution 900 in the window housing device 300 may be a high flow rate (e.g., greater than about 100 sccm). For example, the flow distribution 900 along the inner surface 229 of the optical window 228 may provide a short residence time for any metal fluoride dust 208 near the inner surface 229.

[0127] Exemplary flowchart

[0128] Figure 10 A flowchart 1000 is shown for reducing metal fluoride dust 208 in a window housing device 300 according to one embodiment. It should be understood that this is not necessary. Figure 10 All steps in the document are used to perform the disclosed content. Furthermore, some steps may be performed simultaneously, sequentially, and / or in conjunction with... Figure 10 The different execution orders shown are illustrated. (Refer to...) Figures 2-9 Flowchart 1000 is described in this way. However, flowchart 1000 is not limited to these exemplary embodiments.

[0129] In step 1002, as Figure 2 , Figure 3 and Figure 9 As shown in the example, clean gas (e.g., dust-free) can be directed to flow from MFT 280 through input port 227 of window housing device 300. For example, step 1002 may include... Figure 9The first flow position 902 is shown. In some embodiments, step 1002 may include guiding the flow of cleaning gas through a hole 226 in a plug 225 disposed between the input port 227 and the output port 224 of the MFT 280, and the diameter of the hole 226 may be configured to control the flow rate of the cleaning gas into the window housing device 300.

[0130] In step 1004, as Figures 2-9 As illustrated in the example, a clean gas (e.g., dust-free) can be directed to flow around an aperture device 500 in a window housing 400 surrounding the window housing device 300, and toward an insert 700 disposed between the aperture device 500 and the optical window 228. For example, step 1004 may include... Figure 9 The second and third flow positions 904 and 906 are shown. In some embodiments, step 1004 may include guiding the flow of cleaning gas through shanks 522, 524, 526, and 528 disposed on the second outer surface 514 of the aperture device 500. In some embodiments, step 1004 may also include guiding the flow of cleaning gas through an insert channel 722 in the insert 700'.

[0131] In step 1006, as Figures 2-9 As illustrated in the example, a clean gas (e.g., dust-free) can be directed to flow through the housing channel 412 and housing port 410 of the window housing 400 and along the inner surface 229 of the optical window 228. For example, step 1006 may include... Figure 9 The fourth and fifth flow positions 908 and 910 are shown. In some embodiments, step 1006 may include guiding cleaning gas to flow from the housing channel 412 and housing port 410 along the entire inner surface 229 of the optical window 228.

[0132] In step 1008, as Figures 2-9 As illustrated in the example, a clean gas (e.g., dust-free) can be directed to flow from optical window 228 through aperture device 500. For example, step 1008 may include... Figure 9 The sixth flow position 912 is shown. In some embodiments, step 1008 may include guiding cleaning gas from the inner surface 229 of the optical window 228 to the aperture device 500 and through units 548, 558, 568, 578, and 588, which have a decreasing diameter from the front end 504 to the rear end 502 of the aperture device 500.

[0133] While specific references may be made herein to the use of lithography equipment in IC manufacturing, it should be understood that the lithography equipment described herein may have other applications, such as the fabrication of integrated optical systems, the guiding and detection of patterns for magnetic domain memories, flat panel displays, LCDs, thin-film magnetic heads, etc. Those skilled in the art will understand that, in the context of such alternative applications, any use of the terms “wafer” or “die” herein may be considered synonymous with the more general terms “substrate” or “target portion,” respectively. Before or after exposure, the substrate mentioned herein may be processed in, for example, a coating and developing unit (typically a tool for applying a resist layer to the substrate and developing the exposed resist), a measurement unit, and / or an inspection unit. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Furthermore, for example, to create multilayer ICs, the substrate may be processed more than once, such that the term “substrate” as used herein may also refer to a substrate that has already incorporated multiple processed layers.

[0134] Although the embodiments have been specifically referenced above in the context of optical lithography, it should be understood that the embodiments can be used in other applications, such as imprint lithography, and are not limited to optical lithography where the context permits. In imprint lithography, the morphology in the patterning apparatus defines a pattern created on a substrate. The morphology of the patterning apparatus can be pressed into a resist layer provided to the substrate, whereby the resist is cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. After the resist has cured, the patterning apparatus removes the resist, leaving the pattern therein.

[0135] It should be understood that the wording or terminology used herein is for descriptive rather than limiting purposes, and that the terminology or terminology used herein should be interpreted by those skilled in the art based on the teachings herein.

[0136] As used herein, the term "substrate" describes the material on which a layer of material is added. In some embodiments, the substrate itself may be patterned, and the material added on top of it may also be patterned, or may remain unpatterned.

[0137] The following examples illustrate, but are not limited, embodiments of this disclosure. Other suitable modifications and adaptations to various conditions and parameters commonly encountered in the art (which will be apparent to those skilled in the art) are within the spirit and scope of this invention.

[0138] While specific references may be made herein to the use of devices and / or systems in IC manufacturing, it should be clearly understood that such devices and / or systems have many other possible applications. For example, they can be used to manufacture integrated optical systems, guide and detection patterns for magnetic domain memories, LCD panels, thin-film magnetic heads, etc. Those skilled in the art will understand that, in the context of such alternative applications, any use of the terms “mask,” “wafer,” or “die” herein should be considered to be replaced by the more general terms “mask,” “substrate,” and “target portion,” respectively.

[0139] While specific embodiments have been described above, it should be understood that embodiments may be practiced in ways other than those described. This specification is not intended to limit the scope of the claims.

[0140] It should be understood that the Detailed Description section, rather than the Summary and Abstract section, is intended to be used to interpret the claims. The Summary and Abstract section may set forth one or more, but not all, exemplary embodiments contemplated by the inventors, and is therefore not intended to limit the embodiments and the appended claims in any way.

[0141] The embodiments described above use functional building blocks to illustrate the implementation of specific functions and their relationships. For ease of description, the boundaries of these functional building blocks are arbitrarily defined herein. Alternative boundaries can be defined as long as the specified functions and their relationships are properly executed.

[0142] The above description of the specific embodiments will fully reveal the general nature of the embodiments, enabling others to easily modify and / or adapt various applications of such specific embodiments by applying knowledge of the art without extensive experimentation or departing from the general concept of the embodiments. Therefore, based on the teachings and guidance given herein, such adaptations and modifications are intended to fall within the meaning and scope of equivalents of the disclosed embodiments.

[0143] Other aspects of the invention are set forth in the following numbered clauses.

[0144] 1. A light source device, comprising:

[0145] The chamber is configured to contain a gas discharge medium, which outputs a light beam.

[0146] A metal fluoride trap, coupled to the chamber and configured to capture metal fluoride dust generated from the chamber and provide clean gas along the output port; and

[0147] A set of window housing devices, coupled to the chamber and configured to reduce metal fluoride dust accumulation on the optical window, wherein each window housing device includes:

[0148] The outer shell supporting the optical window;

[0149] An aperture device, coupled to a window housing, includes multiple units configured to capture metal fluoride dust flowing upstream from the chamber through the aperture device toward the optical window; and

[0150] An insert is disposed between the aperture device and the optical window, wherein the insert is configured to control a first flow rate of the cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture device.

[0151] 2. The light source device according to Clause 1, wherein the insert is configured such that a first flow velocity along the optical window is greater than or equal to a second flow velocity through the aperture device.

[0152] 3. The light source device according to Clause 1, wherein the insert includes a channel configured to decrease a first flow velocity along the optical window and increase a second flow velocity through the aperture device.

[0153] 4. The light source device according to Clause 3, wherein the cross-sectional area of ​​the channel is proportional to the decrease of the first flow velocity and the increase of the second flow velocity.

[0154] 5. The light source device according to Clause 1, wherein the window housing device further includes a plug having a hole, the plug being disposed between the input port of the window housing and the output port of the metal fluoride trap.

[0155] 6. The light source device according to Clause 5, wherein the plug and output port are disposed within the frame of the chamber.

[0156] 7. The light source device according to Clause 1, wherein a plurality of prongs are disposed on the outer surface of the aperture device and configured to guide cleaning gas to flow around the aperture device toward the insert, wherein the plurality of prongs include an outer diameter larger than the outer surface of the aperture device to provide clearance for the flow of cleaning gas.

[0157] 8. The light source device according to Clause 1, wherein the window housing includes a channel configured to flush cleaning gas along the optical window.

[0158] 9. The light source device according to Clause 1, wherein the window housing includes a Fresnel beam-catching recess configured to capture and absorb Fresnel reflections from the optical window to achieve a desired reflectance-transmittance ratio for the optical window.

[0159] 10. The light source device according to Clause 1, wherein the gas discharge medium comprises an excimer and / or an excitation complex.

[0160] 11. The light source device according to Clause 10, wherein the gas discharge medium includes F2, ArF, KrF and / or XeF.

[0161] 12. The light source device according to Clause 1 further includes a set of optical elements configured to form an optical resonator around the chamber.

[0162] 13. The light source device according to Clause 12, wherein a set of optical elements comprises:

[0163] An optical coupler for optical communication with the first window housing device; and

[0164] The linewidth narrowing module communicates optically with the second window housing device.

[0165] 14. The light source device according to Clause 12, wherein a set of optical elements comprises:

[0166] The wavefront engineering box communicates optically with the first window housing device; and

[0167] A beam inverter for optical communication with the second window housing device.

[0168] 15. The light source device according to Clause 1, wherein the insert is configured such that a first flow rate of cleaning gas along the optical window is configured to reduce the thermal boundary layer along the inner surface of the optical window.

[0169] 16. A window housing device configured to reduce metal fluoride dust accumulation on an optical window, the window housing device comprising:

[0170] The outer casing of the window supports the optical window;

[0171] An aperture device, coupled to a window housing, includes multiple units configured to capture metal fluoride dust flowing through the aperture device toward the optical window; and

[0172] An insert is positioned between the aperture device and the optical window.

[0173] The insert is configured to control a first flow rate of the cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture device.

[0174] 17. The window housing device according to Clause 16, wherein the window housing includes an aperture configured to receive an aperture device and an insert.

[0175] 18. The window housing device according to Clause 17, wherein the aperture includes an undercut and / or recess configured to increase the volume of cleaning gas in the window housing device.

[0176] 19. The window housing device according to Clause 16, wherein the window housing includes a channel configured to guide cleaning gas to flow along the optical window before flowing through the aperture device.

[0177] 20. The window housing device according to Clause 16, wherein a plurality of prongs are disposed along the outer surface of the aperture device and configured to guide cleaning gas to flow around the aperture device toward the insert, wherein the plurality of prongs are arranged symmetrically.

[0178] 21. The window housing device according to Clause 20, wherein a plurality of prongs of the aperture device mechanically engage with a plurality of recesses in the insert.

[0179] 22. The window housing device according to Clause 16, wherein the aperture device comprises a plurality of units, each configured to capture metal fluoride dust flowing upstream from the chamber through the aperture device toward the optical window.

[0180] 23. The window housing device according to Clause 16, wherein the aperture device comprises at least five units having a diameter decreasing from the front end to the rear end toward the chamber.

[0181] 24. The window housing device according to Clause 16, wherein the window housing device is configured such that a first flow velocity along the optical window is greater than or equal to a second flow velocity through the aperture device.

[0182] 25. The window housing device according to Clause 16, wherein the insert includes a channel configured to reduce a first flow velocity along the optical window and increase a second flow velocity through the aperture device.

[0183] 26. The window housing device according to Clause 25, wherein the cross-sectional area of ​​the channel is proportional to the decrease of the first flow velocity and the increase of the second flow velocity.

[0184] 27. A method for reducing metal fluoride dust accumulation on an optical window in a window housing device, the method comprising:

[0185] The clean gas is guided to flow from the metal fluoride trap through the input port of the window housing device;

[0186] The clean gas is guided to flow around the aperture device located in the window housing of the window housing device and toward the insert located between the aperture device and the optical window;

[0187] The clean gas is guided to flow through channels in the window housing and along the inner surface of the optical window; and

[0188] The clean gas is guided to flow through the aperture device from the optical window.

[0189] 28. The method according to Clause 27, wherein guiding the flow of cleaning gas from the metal fluoride trap comprises: guiding the flow of cleaning gas through an orifice of a plug disposed between an input port and an output port of the metal fluoride trap, wherein the diameter of the orifice is configured to control the flow rate of the cleaning gas into the window housing device.

[0190] 29. The method according to Clause 27, wherein guiding the flow of cleaning gas around the aperture device comprises: guiding the flow of cleaning gas through a plurality of shanks disposed on the outer surface of the aperture device.

[0191] 30. The method according to Clause 27, wherein guiding the flow of cleaning gas around the aperture device comprises: guiding the flow of cleaning gas through a channel in the insert.

[0192] 31. The method according to Clause 27, wherein guiding the flow of cleaning gas through the channel comprises: guiding the cleaning gas from the channel to flow along the entire inner surface of the optical window.

[0193] 32. The method according to Clause 27, wherein guiding the cleaning gas flow from the optical window comprises: guiding the cleaning gas from the inner surface of the optical window toward the aperture device and through a plurality of cells having a diameter decreasing from the front end to the rear end of the aperture device.

[0194] 33. The method according to Clause 27, wherein the optical window forms part of a chamber configured to hold a gas discharge medium for an output beam, and further comprises causing the gas discharge medium to generate the beam.

[0195] The breadth and scope of the embodiments should not be limited by any of the exemplary embodiments described above, but should be defined only by the appended claims and their equivalents.

Claims

1. A light source apparatus comprising: a chamber configured to house a gas discharge medium, the gas discharge medium outputting a light beam; a metal fluoride trap coupled to the chamber and configured to trap metal fluoride dust generated from the chamber and provide a cleaning gas along an output port; and a set of window housing apparatuses coupled to the chamber and configured to reduce metal fluoride dust accumulation on an optical window, wherein each window housing apparatus comprises: a window housing supporting an optical window; an aperture apparatus coupled to the window housing and comprising a plurality of cells configured to trap metal fluoride dust flowing upstream from the chamber through the aperture apparatus towards the optical window; and an insert disposed between the aperture apparatus and the optical window, wherein the insert is configured to control a first flow rate of the cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture apparatus.

2. The light source apparatus of claim 1, wherein the insert is configured such that the first flow rate along the optical window is greater than or equal to the second flow rate through the aperture apparatus.

3. The light source apparatus of claim 1, wherein the insert comprises a channel configured to reduce the first flow rate along the optical window and increase the second flow rate through the aperture apparatus.

4. The light source apparatus of claim 3, wherein a cross-sectional area of the channel is proportional to the reduction of the first flow rate and the increase of the second flow rate.

5. The light source apparatus of claim 1, wherein the window housing apparatus further comprises a plug having an aperture disposed between an input port of the window housing and the output port of the metal fluoride trap.

6. The light source apparatus of claim 5, wherein the plug and the output port are disposed in a frame of the chamber.

7. The light source apparatus of claim 1, wherein a plurality of tangs are disposed on an outer surface of the aperture apparatus and configured to direct the cleaning gas to flow around the aperture apparatus towards the insert, wherein the plurality of tangs comprise an outer diameter greater than the outer surface of the aperture apparatus to provide a gap for the cleaning gas to flow through.

8. The light source apparatus of claim 1, wherein the window housing comprises a channel configured to flush the cleaning gas along the optical window.

9. The light source apparatus of claim 1, wherein the window housing comprises a Fresnel beam capture pocket configured to capture and absorb Fresnel reflections from the optical window to achieve a desired reflectance-transmittance ratio of the optical window.

10. The light source apparatus of claim 1, wherein the gas discharge medium comprises excimers and / or excited complexes.

11. The light source apparatus of claim 10, wherein the gas discharge medium comprises F2, ArF, KrF, and / or XeF.

12. The light source apparatus of claim 1, further comprising a set of optical elements configured to form an optical resonator around the cell.

13. The light source apparatus of claim 12, wherein the set of optical elements comprises: an optical coupler in optical communication with the first window enclosure apparatus; and a line-narrowing module in optical communication with the second window enclosure apparatus.

14. The light source apparatus of claim 12, wherein the set of optical elements comprises: a wavefront engineering box in optical communication with the first window enclosure apparatus; and a beam reverser in optical communication with the second window enclosure apparatus.

15. The light source apparatus of claim 1, wherein the insert is configured such that the first flow rate of the cleaning gas along the optical window is configured to reduce a thermal boundary layer along an inner surface of the optical window.

16. A window enclosure apparatus configured to reduce metal fluoride dust build-up on an optical window, the window enclosure apparatus comprising: a window enclosure supporting the optical window; an aperture apparatus coupled to the window enclosure and comprising a plurality of cells configured to trap metal fluoride dust flowing through the aperture apparatus toward the optical window; and an insert disposed between the aperture apparatus and the optical window, wherein the insert is configured for controlling a first flow rate of a cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture apparatus.

17. The window enclosure apparatus of claim 16, wherein the window enclosure comprises a hole therein configured for receiving the aperture apparatus and the insert.

18. The window enclosure apparatus of claim 17, wherein the hole comprises an undercut and / or a recess configured for increasing a volume of the cleaning gas in the window enclosure apparatus.

19. The window enclosure apparatus of claim 16, wherein the window enclosure comprises a channel configured to direct the cleaning gas to flow along the optical window prior to flowing through aperture apparatus.

20. The window enclosure apparatus of claim 16, wherein a plurality of tangs are disposed along an outer surface of the aperture apparatus and configured to direct the cleaning gas to flow around the aperture apparatus toward the insert, wherein the plurality of tangs are symmetrically arranged.

21. The window enclosure apparatus of claim 20, wherein the plurality of tangs of the aperture apparatus mechanically mate with a plurality of recesses in the insert.

22. The window enclosure apparatus of claim 16, wherein the plurality of cells are configured to trap metal fluoride dust flowing upstream from a cell through the aperture apparatus toward the optical window, wherein the cell is configured to be coupled to the window enclosure apparatus and to contain a gas discharge medium. ​ ​ 23. The window enclosure apparatus of claim 16, wherein the aperture apparatus comprises at least five cells having diameters that decrease from a front end to a back end toward a chamber, wherein the chamber is configured to be coupled to the window enclosure apparatus and to house a gas discharge medium.

24. The window enclosure apparatus of claim 16, wherein the window enclosure apparatus is configured such that the first flow rate along the optical window is greater than or equal to the second flow rate through the aperture apparatus.

25. The window enclosure apparatus of claim 16, wherein the insert comprises a channel configured to decrease the first flow rate along the optical window and to increase the second flow rate through the aperture apparatus.

26. The window enclosure apparatus of claim 25, wherein a cross-sectional area of the channel is proportional to the decrease in the first flow rate and the increase in the second flow rate.

27. A method of reducing metal fluoride build-up on an optical window in a window enclosure apparatus, the method comprising: directing a cleaning gas to flow from a metal fluoride trap through an input port of the window enclosure apparatus; directing the cleaning gas to flow around an aperture apparatus disposed in a window enclosure of the window enclosure apparatus and toward an insert disposed between the aperture apparatus and the optical window, wherein the insert is configured to control a first flow rate of the cleaning gas along the optical window and a second flow rate of the cleaning gas through the aperture apparatus; directing the cleaning gas to flow through a channel in the window enclosure and along an inner surface of the optical window; and directing the cleaning gas to flow from the optical window through the aperture apparatus. directing the cleaning gas to flow through a bore of a plug disposed between the input port and an output port of the metal fluoride trap, wherein a diameter of the bore is configured to control a flow rate of the cleaning gas into the window enclosure apparatus.

28. The method of claim 27, wherein directing a flow of cleaning gas from the metal fluoride trap comprises: directing the cleaning gas to flow through a plurality of tangs disposed on an outer surface of the aperture apparatus.

29. The method of claim 27, wherein directing the cleaning gas to flow around the aperture device comprises: directing the cleaning gas to flow through a channel in the insert.

30. The method of claim 27, wherein directing the cleaning gas to flow around the aperture device comprises: directing the cleaning gas to flow from the channel along an entire inner surface of the optical window.

31. The method of claim 27, wherein directing the flow of cleaning gas through the passageway comprises: directing the cleaning gas to flow from the inner surface of the optical window toward the aperture apparatus and through a plurality of cells having diameters that decrease from a front end to a back end of the aperture apparatus.

32. The method of claim 27, wherein directing the flow of the cleaning gas from the optical window comprises:

33. The method of claim 27, wherein the optical window forms a portion of a chamber configured to be coupled to the window enclosure apparatus and to hold a gas discharge medium of an output light beam, and further comprising causing the gas discharge medium to generate a light beam. ​

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