Systems and methods of etching in light source

Abstract

A light source includes a vessel containing a first liner, wherein the first liner has a frustum shape, an exhaust module arranged adjacent to the first liner, an etching component arranged adjacent to the exhaust module, and a gas supply coupled to the etching component. The etching component includes at least one antenna.

Description

SYSTEMS AND METHODS OF ETCHING IN LIGHT SOURCECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to US Application No. 63 / 690,612, filed September 4, 2024, titled SYSTEMS AND METHODS OF ETCHING IN LIGHT SOURCE, which is incorporated herein by reference in its entirety.FIELD

[0002] The present application relates to extreme ultraviolet (“EUV”) radiation sources and methods thereof. EUV radiation can be used as, for example, exposure radiation in a lithographic process or a metrology process within semiconductor manufacturing.BACKGROUND

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which can be a mask or a reticle, can be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g., comprising part of, one, or several dies) on a substrate (e.g., a silicon wafer). Transfer ofthe pattern is typically via imaging onto a layer of radiationsensitive material (photoresist or simply “resist”) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatuses include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”- direction) while synchronously scanning the target portions parallel or anti-parallel to this scanning direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004] A metrology apparatus is a machine that applies in semiconductor manufacturing to measure and inspect the critical dimensions and properties of wafers and their components. By providing precise measurements and analysis, the metrology apparatus plays a crucial role in ensuring the reliability and yield of the manufacturing process.

[0005] In some aspects, a lithographic apparatus or a metrology apparatus includes an illumination system that conditions radiation generated by a radiation source before the radiation is incident upon a patterning device. A patterned beam of EUV light can be used to produce extremely small features on a substrate. EUV light (also sometimes referred to as soft x-rays) is generally defined as electromagnetic radiation having wavelengths in the range of about 5-100 nm. One particular wavelength of interest for photolithography occurs at 13.5 nm.

[0006] Methods to produce EUV light include, but are not necessarily limited to, converting a source material into a plasma state that has a chemical element with an emission line in the EUV range. These elements can include, but are not necessarily limited to, xenon, lithium and tin. In one such method, often termed laser-produced plasma (“LPP”), the desired plasma can be produced by irradiating a source material, for example, in the form of a droplet, stream or wire, with a laser beam inside of a chamber.

[0007] During EUV production some source material is not converted into a plasma. Furthermore, a laser-produced plasma can revert back into a prior phase of matter (e .g . , liquid or vapor) . This can create source material debris, which, when left inside the chamber, can deposit on chamber walls and components.

[0008] Existing methods of removing source material debris from a chamber include configuring gas flows to direct source material debris away from critical components and towards an exhaust module. A scrubber can be positioned in the exhaust module to collect and remove source material debris from the gas flows. However, a portion of the source material debris can still deposit on walls of the chamber and exhaust module, thereby decreasing the lifespan of components contained therein.SUMMARY

[0009] Accordingly, it is desirable to develop efficient systems and methods for removing deposited source material form the walls of a chamber and exhaust module in a light source. For example, deposited source material can be etched from the surface of a chamber or exhaust module via plasma etching or the like.

[0010] In some aspects, a lithography apparatus includes an extreme ultraviolet (EUV) light source. The EUV light source can include a chamber containing a liner, an exhaust module configured to remove materials from the chamber, and one or more etching components. At least one of the one or more etching components can be positioned to remove source material debris from the exhaust module.

[0011] In some aspects, a method comprises a generating step and a removing step. During the generating step, a plasma state of a material can be created. The plasma state of material can include ions and / or radicals configured to remove source material debris. During the removing step, source material debris can be removed from at least a surface of an exhaust module via etching. The exhaust module can be coupled to a liner in a chamber of an ultraviolet light source.

[0012] Further features of various aspects of the present disclosure are described in detail below with reference to the accompanying drawings. It is noted that the present disclosure is not limited to the specific aspects described herein. Such aspects are presented herein for illustrative purposes only. Additional aspects will be apparent to those skilled in the relevant art(s) based on the teachings contained herein.BRIEF DESCRIPTION OF THE DRAWINGS / FIGURES

[0013] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art(s) to make and use aspects described herein.

[0014] FIG. 1 shows a reflective lithographic apparatus, according to some aspects.

[0015] FIGS. 2A, 2B, and 3 show more details of a reflective lithographic apparatus, according to some aspects.

[0016] FIG. 4 shows a lithographic cell, according to some aspects.

[0017] FIG. 5 shows a debris mitigation system, according to some aspects.

[0018] FIG. 6A shows an etching device, according to some aspects.

[0019] FIG. 6B shows an etching process, according to some aspects.

[0020] FIGS. 7A, 7B, 7C, 7D and 7E show plasma generation techniques, according to some aspects.

[0021] FIGS. 8A, 8B, and 8C show example integrations of etching components in a light source, according to some aspects.

[0022] FIG. 9 shows a method, according to some aspects.

[0023] FIG. 10 shows a flowchart of light source operations, according to some aspects.

[0024] The features of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, generally, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears. Unless otherwise indicated, the drawings provided throughout the disclosure should not be interpreted as to-scale drawings.DETAILED DESCRIPTION

[0025] The aspects described herein, and references in the specification to “one aspect,” “an aspect,” “an exemplary aspect,” “an example aspect,” etc., indicate that the aspects described can include a particular feature, structure, or characteristic, but every aspect may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same aspect. Further, when a particular feature, structure, or characteristic is described in connection with an aspect, it is understood that it is within the knowledge of those skilled in the art to effect such feature, structure, or characteristic in connection with other aspects whether or not explicitly described.

[0026] Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “on,” “upper” and the like, can be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended toencompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein can likewise be interpreted accordingly.

[0027] The terms “about,” “approximately,” or the like can be used herein indicates the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the terms “about,” “approximately,” or the like can indicate a value of a given quantity that varies within, for example, 10-30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0028] Aspects of the present disclosure can be implemented in hardware, firmware, software, or any combination thereof. Aspects of the disclosure can also be implemented as instructions stored on a computer-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 form readable by a machine (e.g., a computing device). For example, a machine-readable medium can comprise read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Furthermore, firmware, software, routines, and / or instructions can be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc. The term “machine-readable medium” can be interchangeable with similar terms, for example, “computer program product,” “computer-readable medium,” “non-transitory computer- readable medium,” or the like. The term “non-transitory” can be used herein to characterize one or more forms of computer readable media except for a transitory, propagating signal.

[0029] Before describing such aspects in more detail, however, it is instructive to present an example environment in which aspects of the present disclosure can be implemented.

[0030] Example Lithographic Systems

[0031] FIG. 1 shows a lithographic apparatus 100 in which aspects of the present disclosure can be implemented. In some aspects, lithographic apparatus 100 can comprise the following: an illumination system (illuminator) IL configured to condition a radiation beam B (for example, deep ultra violet or extreme ultra violet radiation); a support structure (for example, a mask table) MT configured to support a patterning device (for example, a mask, a reticle, or a dynamic patterning device) MA and connected to a first positioner PM configured to accurately position patterning device MA; and, a substrate table (for example, a wafer table) WT configured to hold a substrate (for example, a resist coated wafer) W and connected to a second positioner PW configured to accurately position substrate W. Lithographic apparatus 100 also comprises a projection system PS configured to project a pattern imparted to radiation beam B by patterning device MA onto a target portion (for example, comprising one or more dies) C of substrate W. In lithographic apparatus 100, patterning device MA and the projection system PS are reflective.

[0032] Illumination system IL can comprise various types of optical components, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for directing, shaping, or controlling the radiation beam B. Illumination system IL can also comprise a sensor ES that provides a measurement of, for example, one or more of energy per pulse, photon energy, intensity, average power, and the like. Illumination system IL can comprise a measurement sensor MS for measuring a movement of radiation beam B and a uniformity compensator UC that allow an illumination slit uniformity to be controlled. Measurement sensor MS can also be disposed at other locations. For example, measurement sensor MS can be on or near substrate table WT.

[0033] In some aspects, support structure MT can support patterning device MA in a manner that depends on the orientation of the patterning device MA with respect to a reference frame, the design of lithographic apparatus 100, and other conditions, such as whether or not the patterning device MA is held in a vacuum environment. Support structure MT can implement mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device MA. Support structure MT can be a frame or a table. Support structure MT can be fixed or movable. By using sensors, support structure MT can ensure that patterning device MA is at a desired position (e.g., a given position with respect to the projection system PS).

[0034] The term “patterning device” can be used herein to refer to any device that can be used to impart a radiation beam B with a pattern in its cross-section, such as to create a pattern in target portion C of substrate W. The pattern imparted to radiation beam B can correspond to a particular functional layer in a device being created in target portion C to form an integrated circuit.

[0035] Patterning device MA can be reflective. Examples of patterning devices MA include reticles, masks, programmable mirror arrays, or programmable LCD panels. Masks can include different mask types, such as binary, alternating phase shift, or attenuated phase shift, 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 so as to reflect an incoming radiation beam in different directions. The tilted mirrors can impart a pattern in radiation beam B, which is reflected by a matrix of small mirrors.

[0036] In some aspects, the term “projection system” can be used herein to refer to any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for other factors, such as the use of an immersion liquid on the substrate W or the use of a vacuum. Atmospheric gas can absorb EUV or electrons used for exposing a substrate. Therefore, a vacuum environment can be used for EUV or electron beam radiation. A vacuum environment can be provided to the whole beam path with the aid of a vacuum wall and vacuum pumps.

[0037] Lithographic apparatus 100 can be of a type having two (dual stage) or more substrate tables WT (and / or two or more mask tables). In such “multiple stage” machines, additional substrate tablesWT can be used in parallel, or preparatory steps can be carried out on one or more tables while one or more other substrate tables WT are being used for exposure. In some situations, the additional table may be different from substrate table WT.

[0038] In some aspects, lithographic apparatus 100 can be of a type in which at least a portion of the substrate can be covered by a liquid having a relatively high refractive index, e.g., water, so as to fdl a space between the projection system and the substrate. An immersion liquid can also be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques can increase the numerical aperture of projection systems. The term “immersion” as used herein does not mean that a structure, such as a substrate, must be submerged in liquid. For example, a liquid can be located between the projection system and the substrate during exposure.

[0039] Illuminator IL can receive a radiation beam from a radiation source SO. Source SO and lithographic apparatus 100 can be separate physical entities. In such cases, source SO is not considered to be part of lithographic apparatus 100 and radiation beam B can pass from source SO to illuminator IL with the aid of a beam delivery system (not shown), which can include, for example, suitable directing mirrors and / or a beam expander. In other cases, source SO can be an integral part of the lithographic apparatus 100. A radiation system can comprise source SO, illuminator IL, and / or beam delivery system BD.

[0040] In some aspects, illuminator IL can be used to condition radiation beam B to have a desired uniformity and intensity distribution in its cross section. The desired uniformity of radiation beam B can be maintained by using uniformity compensator UC. Uniformity compensator UC can comprise a plurality of protrusions (e.g., fingers) that can be adjusted in the path of radiation beam B to control the uniformity of radiation beam B. Measurement sensor MS can be used to monitor the uniformity of radiation beam B.

[0041] Radiation beam B can be incident on patterning device MA, which is held on the support structure MT, and in this manner, radiation beam B can be patterned by the patterning device MA. In lithographic apparatus 100, radiation beam B can be reflected from the patterning device (for example, mask) MA. After being reflected from the patterning device MA, radiation beam B can pass through projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. With the aid of the second positioner PW and position sensor IF2 (for example, an interferometric device, linear encoder, or capacitive sensor), substrate table WT can be moved accurately (for example, so as to position different target portions C in the path of the radiation beam B). Similarly, first positioner PM and another position sensor IF1 can be used to accurately position the patterning device (for example, mask) MA with respect to the path of the radiation beam B. Patterning device MA and substrate W can be aligned using mask alignment marks Ml, M2 and substrate alignment marks Pl, P2.

[0042] In some aspects, lithographic apparatus 100 can be used in at least one of the following modes:

[0043] 1. In step mode, support structure MT and substrate table WT can be kept essentially stationary, while an entire pattern imparted to radiation beam B is projected onto a target portion C at one time (e.g., a single static exposure). Substrate table WT can then be shifted in the X and / or Y direction so that a different target portion C can be exposed.

[0044] 2. In scan mode, support structure MT and substrate table WT can be scanned synchronously while a pattern imparted to radiation beam B is projected onto a target portion C (e.g., a single dynamic exposure). The velocity and direction of substrate table WT relative to support structure MT can be determined by (de-)magnification and image reversal characteristics of projection system PS.

[0045] 3. In another mode, support structure MT can be kept substantially stationary holding a programmable patterning device, and substrate table WT can be moved or scanned while a pattern imparted to radiation beam B is projected onto a target portion C. A pulsed radiation source SO can be employed and the programmable patterning device is updated after each movement of substrate table WT or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes a programmable patterning device, such as a programmable mirror array.

[0046] Combinations and / or variations on the described modes of use or entirely different modes of use can also be employed.

[0047] In some aspects, lithographic apparatus 100 can comprise an EUV radiation source configured to generate a beam of EUV radiation for EUV lithography. The EUV radiation source can be configured in a radiation system, and a corresponding illumination system is configured to condition the EUV radiation beam of the EUV source.

[0048] FIG. 2A shows different view of lithographic apparatus 100, including source SO (e.g., source collector apparatus), illumination system IL, and projection system PS, according to some aspects. Source SO is constructed and arranged such that a vacuum environment can be maintained in an enclosing structure 220 of source SO. An EUV radiation emitting plasma 210 can be formed by a discharge-generated plasma source. In some aspects, a plasma of excited tin (Sn) (e.g., excited via a laser) is used to produce EUV radiation.

[0049] The radiation emitted by the EUV radiation emitting plasma 210 can be passed from a source chamber 211 into a collector chamber 212 via an optional gas barrier or contaminant trap 230 (in some cases also referred to as contaminant barrier or foil trap), which is positioned in or behind an opening in source chamber 211. Contaminant trap 230 can comprise a channel structure. Contamination trap 230 can also comprise a gas barrier and / or a channel structure.

[0050] In some aspects, collector chamber 212 can comprise a radiation collector CO. Radiation collector CO can be a so-called grazing incidence collector. Radiation collector CO can comprise an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation that traverses radiation collector CO can be reflected off a grating spectral filter 240 to be focused in a virtualsource point INTF. Virtual source point INTF can be referred to as the intermediate focus. Source collector apparatus can be arranged such that the intermediate focus INTF is located at or near an opening 219 of enclosing structure 220. The virtual source point INTF can be an image of the EUV radiation emitting plasma 210. Grating spectral fdter 240 can be used for suppressing infrared (IR) radiation. In some aspects, grating spectral fdter 240 is not required and intermediate focus INTF refers to a location where the radiation is directly focused from radiation collector CO before travelling towards illumination system IL of lithographic apparatus 100 or a metrology apparatus.

[0051] Subsequently, the radiation traverses the illumination system IL. Illumination system IL can include a faceted field mirror device 222 and a faceted pupil mirror device 224 arranged to provide a desired angular distribution of radiation beam 221, at patterning device MA, as well as a desired uniformity of radiation intensity at patterning device MA. Upon reflection of beam of radiation 221 at patterning device MA, held by support structure MT, a patterned beam 226 is formed and the patterned beam 226 is imaged by projection system PS via reflective elements 228, 229 onto substrate W held by the wafer stage or substrate table WT. In some aspects, other configurations of mirrors and / or optical devices can be used to direct radiation beam 221 to patterning device MA.

[0052] More elements than shown can generally be present in illumination system IL and projection system PS. Grating spectral filter 240 can optionally be present, depending upon the type of lithographic apparatus. Further, there can be more mirrors present than those shown in the FIG. 2A, for example there can be one to six additional reflective elements present in the projection system PS than shown in FIG. 2A.

[0053] In some aspects, uniformity compensator UC, sensor ES, and / or measurement sensor MS shown in FIGS. 2A and 2B can be as described above in reference to FIG. 1.

[0054] Collector CO (also called a collector mirror or collector optic), as illustrated in FIG. 2A, is depicted as an example of a nested collector with grazing incidence reflectors 253, 254, and 255. Grazing incidence reflectors 253, 254, and 255 can be disposed axially symmetric around an optical axis O. A collector of this type can be used in combination with a discharge -generated plasma source, often called a DPP source.

[0055] FIG. 2B shows a portion of lithographic apparatus 100 (e.g., FIG. 1), but with alternative collection optics in source SO, according to some aspects. It should be appreciated that structures shown in FIG. 2A that do not appear in FIG. 2B (for drawing clarity) can still be included in aspects referring to FIG. 2B. Elements in FIG. 2B having the same reference numbers as those in FIG. 2A have the same or substantially similar structures and functions as described in reference to FIG. 2A. In some aspects, the lithographic apparatus 100 can be used, for example, to expose a substrate W such as a resist-coated wafer with a patterned beam of EUV illumination. In FIG. 2B, illumination system IL and projection system PS are represented combined as an exposure device 256 (e.g., an integrated circuit lithography tool such as a stepper, scanner, step and scan system, direct write system, device using a contact and / or proximity mask, etc.) that uses EUV light from source SO. Lithographic apparatus 100 can alsocomprise a collector 258 that reflects EUV light from the EUV radiation emitting plasma 210 along a path into the exposure device 256 to irradiate substrate W. Collector 258 can comprise a near-normal incidence collector mirror having a reflective surface in the form of a prolate spheroid (e.g., an ellipse rotated about its major axis). The prolate spheroid structure can have a graded multi-layer coating with alternating layers of molybdenum and silicon, and in some cases, one or more high temperature diffusion barrier layers, smoothing layers, capping layers and / or etch stop layers.

[0056] FIG. 3 shows a detailed view of a portion of lithographic apparatus 100 (e.g., FIGS. 1, 2A, and 2B), according to one or more aspects. Elements in FIG. 3 having the same reference numbers as those in FIGS. 1, 2A, and 2B have the same or substantially similar structures and functions as described in reference to FIGS. 1, 2A, and 2B. In some aspects, source SO can be a LPP EUV source. Source SO can comprise a laser system 302 for generating a train of light pulses and delivering the light pulses into a light source chamber 212. For the lithographic apparatus 100, the light pulses can travel along one or more beam paths from the laser system 302 and into the chamber 212 to illuminate a source material at an irradiation region 304 to generate a plasma (e.g., plasma region located at EUV radiation emitting plasma 210 in FIG. 2B) that produces EUV light for substrate exposure in the exposure device 256.

[0057] In some aspects, laser system 302 can comprise a pulsed laser device, e.g., a pulsed gas discharge CO2 laser device producing radiation at 9.x pm or 10.x pm, e.g., with DC or RF excitation, operating at relatively high power, e.g., 10 kW or higher and high pulse repetition rate, e.g., 50 kHz or more. In some aspects, the laser can be an axial-flow RF-pumped CO2 laser having an oscillator amplifier configuration (e.g., master oscillator / power amplifier (MOPA) or power oscillator / power amplifier (POPA)) with multiple stages of amplification and having a seed pulse that is initiated by a Q-switched oscillator with relatively low energy and high repetition rate, e.g., capable of 100 kHz operation. From the oscillator, the laser pulse can then be amplified, shaped and / or focused before reaching the irradiation region 304. Continuously pumped CO2 amplifiers can be used for the laser system 302. Alternatively, the laser can be configured as a so-called “self-targeting” laser system in which the droplet serves as one mirror of the optical cavity of the laser.

[0058] In some aspects, depending on the application, other types of lasers can also be suitable, e.g., an excimer or molecular fluorine laser operating at high power and high pulse repetition rate. Some examples include, a solid state laser, e.g., having a fiber, rod, slab, or disk-shaped active media, other laser architectures having one or more chambers, e.g., an oscillator chamber and one or more amplifying chambers (with the amplifying chambers in parallel or in series), a master oscillator / power oscillator (MOPO) arrangement, a master oscillator / power ring amplifier (MOPRA) arrangement, or a solid state laser that seeds one or more excimer, molecular fluorine or CO2 amplifier or oscillator chambers, can be suitable. Other suitable designs are envisaged.

[0059] In some aspects, a source material can first be irradiated by a pre -pulse and thereafter irradiated by a main pulse. Pre-pulse and main pulse seeds can be generated by a single oscillator or two separate oscillators. One or more common amplifiers can be used to amplify both the pre -pulse seed and mainpulse seed. In some aspects, separate amplifiers can be used to amplify the pre-pulse and main pulse seeds.

[0060] In some aspects, a source material can first be irradiated by a pre-pulse, thereafter irradiated by a rarefication pulse, and thereafter irradiated by a main pulse. Pre-pulse, rarefication pulse, and main pulse seeds can be generated by up to three separate oscillators. One or more common amplifiers can be used to amplify the pre-pulse, rarefication pulse, and main pulse seeds.

[0061] In some aspects, source SO can also comprise a beam conditioning unit 306 having one or more optics for beam conditioning, such as expanding, steering, and / or focusing the beam between the laser system 302 and irradiation region 304. For example, a steering system, which can comprise one or more mirrors, prisms, lenses, etc., can be provided and arranged to steer the laser focal spot to different locations in the chamber 212. For example, the steering system can comprise a first flat mirror mounted on a tip-tilt actuator, which can move the first mirror independently in two dimensions, and a second flat mirror mounted on a tip-tilt actuator which can move the second mirror independently in two dimensions. With the described arrangement(s), the steering system can controllably move the focal spot in directions substantially orthogonal to the direction of beam propagation (beam axis or optical axis).

[0062] Beam conditioning unit 306 can comprise a focusing assembly to focus the beam to irradiation region 304 and adjust the position of the focal spot along the beam axis. For the focusing assembly, an optic, such as a focusing lens or mirror, can be used that is coupled to an actuator for movement in a direction along the beam axis to move the focal spot along the beam axis.

[0063] In some aspects, the source SO can also comprise a source material delivery system 308 for delivering source material, such as tin droplets, to irradiation region 304, where the droplets can interact with light pulses from the laser system 302 to produce plasma and generate an EUV emission. The EUV emission is used to expose a substrate such as a resist-coated wafer at exposure device 256. More details regarding various droplet dispenser configurations can be found in, e.g., U.S. Pat. No. 7,872,245, issued on January 18, 2011, titled “Systems and Methods for Target Material Delivery in a Laser Produced Plasma EUV Light Source”, U.S. Patent No. 7,405,416, issued on July 29, 2008, titled “Method and Apparatus For EUV Plasma Source Target Delivery”, U.S. Pat. No. 7,372,056, issued on May 13, 2008, titled “LPP EUV Plasma Source Material Target Delivery System”, and U.S. Patent No. 11,240,904, titled “Apparatus for and Method of Controlling Coalescence of Droplets In a Droplet Stream”, issued on February 1, 2022, the contents of each of which are incorporated by reference herein in their entirety.

[0064] In some aspects, the source material for producing an EUV light output for substrate exposure can include, but is not necessarily limited to, a material that includes tin, lithium, xenon or combinations thereof. The source material can be in the form of liquid droplets and / or solid particles contained within liquid droplets. For example, the element tin can be used as pure tin, as a tin compound, e.g., SnBr4, SnBr2, SnFL, as a tin alloy, e.g., tin-gallium alloys, tin-indium alloys, tin-indium-gallium alloys, or a combination thereof. Depending on the material used, the source material, when sent to irradiationregion 304, can be at various temperatures, for example, room temperature or near room temperature (e.g., tin alloys, SnBrO, at an elevated temperature (e.g., pure tin), or at temperatures below room temperature (e.g., SnH ).

[0065] In some aspects, the source SO can also comprise a controller 310 and / or a drive laser control system 312 for controlling devices in laser system 302 to generate light pulses for delivery into the chamber 212 and / or for controlling movement of optics in beam conditioning unit 306. Source SO can also comprise a droplet position detection system which can comprise one or more droplet imagers 314 that provide an output signal indicative of the position of one or more droplets (e.g., to ensure that droplets arrive on target at irradiation region 304). The droplet imager(s) 314 can provide measurement output to a droplet position detection feedback system 316. Droplet position detection feedback system 316 can compute a droplet position and trajectory, from which a droplet error can be computed (e.g., on a droplet-by-droplet basis, or on average). The droplet error can then be provided as an input to controller 310, which can, for example, provide a position, direction and / or timing correction signal to laser system 302 to control laser trigger timing and / or to control movement of optics in beam conditioning unit 306, e.g., to change the location and / or focal power of the light pulses being delivered to irradiation region 304 in chamber 212. Furthermore, source material delivery system 308 can comprise a control system operable in response to a signal from controller 310 (which in some implementations can include the droplet error described above, or some quantity derived therefrom) to modify the release point, initial droplet stream direction, droplet release timing and / or droplet modulation to correct for errors in the droplets arriving at irradiation region 304.

[0066] In some aspects, the lithographic apparatus 100 can also comprise collector 258 and a gas dispenser device 320. Gas dispenser device 320 can dispense gas in the path of the source material from source material delivery system 308 (e.g., irradiation region 304). Gas dispenser device 320 can comprise a nozzle through which dispensed gas can exit. Gas dispenser device 320 can be structured (e.g., having an aperture) such that, when placed near the optical path of laser system 302, light from laser system 302 is not blocked by gas dispenser device 320 and is allowed to reach irradiation region 304. A buffer gas such as hydrogen, helium, argon or combinations thereof, can be introduced into chamber 212. The buffer gas can be present in the chamber 212 during plasma discharge and can act to slow plasma-created ions, reduce degradation of optics, and / or increase plasma efficiency. Alternatively, a magnetic field and / or electric field (not shown) can be used alone, or in combination with a buffer gas, to reduce damage caused by fast-moving ions.

[0067] In some aspects, collector 258 can be a near-normal incidence collector mirror having a reflective surface in the form of a prolate spheroid as described above. Collector 258 can be formed with an aperture to allow the light pulses generated by laser system 302 to pass through and reach irradiation region 304. The same, or another aperture, can be used to allow gas from the gas dispenser device 320 to flow into chamber 212. As shown, the collector 258 can be, e.g., aprolate spheroid mirror that has a first focus within or near the irradiation region 304 and a second focus at an intermediateregion 318, where the EUV light can be transmitted to exposure device 256. It is to be appreciated that other optics can be used in place of the prolate spheroid mirror for collecting and directing light to an intermediate location for subsequent delivery to a device utilizing EUV light. It is also envisaged that structures and functions described in reference to FIG. 3 can be used with collectors other than collector 258 (e.g., collector CO (FIG. 2A)).

[0068] Example Lithographic Cell

[0069] FIG. 4 shows a lithographic cell 400, also sometimes referred to a lithocell or cluster, according to some aspects. Lithographic apparatus 100 (FIGS. 1, 2A, 2B, and 3) can form part of lithographic cell 400. Lithographic cell 400 can also comprise one or more apparatuses to perform pre -exposure and post-exposure processes on a substrate. These can include spin coaters SC to deposit resist layers, developers DE to develop exposed resist, chill plates CH, and bake plates BK. A substrate handler, or robot, RO picks up substrates from input / output ports I / Ol, I / O2, moves them between the different process apparatuses and delivers them to the loading bay LB of the lithographic apparatus 100. These devices, which are often collectively referred to as the track, are under the control of a track control unit TCU, which is itself controlled by a supervisory control system SCS, which also controls the lithographic apparatus via lithography control unit LACU. Thus, the different apparatuses can be operated to maximize throughput and processing efficiency.

[0070] Example Debris Management Methods

[0071] During EUV production some source material is not converted into a plasma. Furthermore, a laser-produced plasma can revert back into a prior phase of matter (e.g., liquid or vapor). This creates source material debris, which can deposit on chamber walls and components.

[0072] In order to mitigate debris deposition, gas flows can be configured to direct source material debris away from critical components and towards an exhaust module. A scrubber can be positioned in the exhaust module to collect and remove source material debris from the gas flows. However, a portion of the source material debris still deposits on surfaces of the chamber and exhaust module, thereby decreasing their lifespan.

[0073] In some aspects, a heating method can be implemented to clean source material debris form surfaces inside the chamber and / or exhaust module. The heating method can comprise heating surfaces to a temperature above a source material melting point. This allows source material debris to drip off of the surfaces and into a collector. However, during heating, hydrogen radicals in the chamber can react with the source material debris to form bubbles, which can carry the source material debris towards an intermediate focus, thereby causing contamination of the intermediate focus and a scanner of a lithography apparatus.

[0074] In some aspects, integrating plasma etching components into a chamber and exhaust module of a light source can provide cleaning for critical surfaces and components. Plasma etching can occur at a temperature below a melting point of a source material. Thus, plasma etching does not carry the same contamination risks as the heating method described above.

[0075] FIG. 5 shows a schematic of debris management in a light source 500, according to some aspects. Light source 500 can include a chamber 501, a vessel 502 and an exhaust module 504.

[0076] In some aspects, vessel 502 is coupled to a source material delivery system 506 configured to deliver source material 508 (e.g., tin droplets) to irradiation region 510. In irradiation region 510, source material 508 can interact with light pulses from laser 512 to generate a plasma 514. Plasma 514 can generate EUV light.

[0077] Vessel 502 additionally comprises a plurality of liners 516a-c and a cap structure 517. Cap structure 517 is situated at one end of vessel 502 and coupled to liner 516b. In some aspects, cap structure 517 has a substantially conical shape. Cap structure 517 determines a location of an intermediate focus 520 and has openings to introduce gas to form a jet flow or a curtain flow that prevents debris from escaping through intermediate focus 520. In some aspects, cap structure 517 includes multiple conical and frustum sub -components. Liners 516a-c form a shape that allows EUV light produced in irradiation region 510 to pass from a collector 518 to intermediate focus 520 without being blocked. For example, a combination of liners 516a-c and cap structure 517 from a conical shape that tapers smoothly from a flat base near collector 518 to cap structure 517 that opens near intermediate focus 520, as shown in FIG. 5. In additional implementations, a combination of liners 516a-c and cap structure 517 can have a substantially cylindrical shape.

[0078] The process of generating EUV light can produce debris 521, which can deposit on surfaces inside vessel 502. Debris 521, which can include vapor residue, ions, particles, and / or clusters of matter, can be formed from leftover source material 508 that is not completely converted into plasma, or from a plasma that has reverted back into a prior phase of matter (e.g., vapor or liquid). Debris 521 can also be produced from materials other than source material 508 which are present within vessel 502.

[0079] In some aspects, vessel 502 can include a gas dispenser 522, which can dispense gas in the path of the source material 508 (e.g., irradiation region 510). The gas can direct debris 521 into exhaust module 504, thus mitigating deposition on surfaces inside vessel 502.

[0080] In some aspects, exhaust module 504 can include a passthrough 523, an exhaust transition 524, a scrubber 526, a gas cooler 528, and a contaminant passageway 530. Exhaust transition 524 can be coupled to liner 516 through exhaust passthrough 523. In some aspects, a plenum (not shown) surrounds liner 516a and is coupled to both exhaust passthrough 523 and exhaust transition 524. In an alternative embodiment, exhaust transition 524 can be angled to direct debris away from vessel 502. The relative positioning of material delivery system 506 and exhaust module 504 in Fig. 5 is for illustrative purposes only and does not necessarily reflect their actual spatial orientation. In some aspects, exhaust module 504 extends perpendicular or angles to the plane of the figure, while material delivery system 506 extends within the plane of the figure.

[0081] In some aspects, a first portion 530A of contaminant passageway 530 can connect exhaust transition 524 and scrubber 526. Scrubber 526 can be configured to collect debris 521 from gas flowing through exhaust module 504. Components of scrubber 526 can be heated above a melting point of debris521, thus allowing debris 521 to drip from scrubber 526 into a debris collection system (not shown). Gas exiting scrubber 526 can enter gas cooler 528. Gas cooler 528 can be configured to cool the gas using cooling components, such as cooling fluid lines or the like.

[0082] In some aspects, debris 521 can deposit on surfaces of exhaust module 504. To aid in debris mitigation, portions of exhaust module 504 (e.g., exhaust passthrough 523, exhaust transition 524, scrubber 526, and first portion of contaminant passageway 530A) can contain heating components (e.g., resistive wiring). The heating components can keep the temperature of portions of exhaust module 504 above a melting point of source material 508. This can allow deposited source material debris to melt and drip form the surface of components in the exhaust module, thus reducing contamination.

[0083] As an alternative, or in addition to, the heating components, one or more etching components532 can be added to vessel 502 and / or exhaust module 504 to aid in debris management. One or more etching components 532 can generate plasma by ionizing a gaseous material, such as a hydrogencontaining gas, in a region 533 coupled with a gas supply 534 via a fluid connection 535. Region 533 can be a cavity or a duct adjacent to liners 516a-c and / or exhaust module 504. In some aspects region533 is coupled to a waveguide. The plasma includes particles that react with debris 521, causing it to lift away from internal surfaces of vessel 502. As such, at least in one embodiment, liners 516a-c, and / or exhaust module 504 is devoid of any heating components and not connected to any heating source.

[0084] In some aspects, one or more etching components 532 are embedded in (or suspended near) surfaces of vessel 502 and exhaust module 504. One or more etching components 532 can be located in areas of high debris deposition, such as near or inside of liners 516a-c, exhaust passthrough 523, exhaust transition 524, scrubber 526, and contaminant passageway 530.

[0085] FIGS. 6A and 6B show schematics of plasma formation and etching, according to some aspects. During plasma formation, an etching component 602 can generate a strong electromagnetic or electric field in a region 604. In some aspects, region 604 is defined by a cavity and coupled to a gas supply via a fluid connection. The electromagnetic or electric field is applied to gas molecules 606 to create plasma 608 through ionization of gas molecules 606. In some aspects, an electromagnetic surface wave is generated and propagates along an interface between a dielectric material and plasma 608, which is generated from interaction between the surface wave and gas molecules 606. Plasma 608 can consist of particles 610, which include ions, electrons, free radicals, orthe like.

[0086] Etching component 602 is positioned on a surface 612. Surface 612 is located on either the interior or exterior wall of a vessel. In some aspects, surface 612 is located on at least one of a liner of the vessel, an exhaust passthrough, an exhaust transition, and a contaminant passageway. In some aspects, surface 612 is recessed into the interior wall of the liner, the exhaust passthrough, and / or the exhaust transition. Debris material 614, deposited over surface 612, can interact with particles 610 to form a new chemical 616, which can be composed of a combination of elements present in particles 610 and debris material 614. New chemical 616 can release from surface 612, thereby cleaning the surface of debris material 614. In some aspects, while debris material 614 is not directly in contact withsurface 612, particles 610 generated by plasma 608 can interact with debris material 614. In some aspects, a block (not shown) is arranged between surface 612 and debris material 614.

[0087] In one aspect, debris material 614 can include tin particles (e.g., tin or tin oxide) and plasma 608 can be produced from molecular hydrogen (H2) present in a light source. In this case, particles 610 can include free radicals and ions of hydrogen. For example, a free radical can comprise a single hydrogen element with an unpaired valence electron (H*), or a hydrogen atom or a hydrogen molecule that loses one electron (H+or I ) . During the etching process, the generated hydrogen radicals H* can bond with tin particles in debris material 614 to form a tin hydride (SnH ). The tin hydride can be released form surface 612 and, in some aspects, carried away by advection and / or gas flows towards exhaust module

[0088] In some aspects, gas flows (not shown) can be configured to move particles 610 to a region of surface 612 that is not proximate to an etching component. Plasma particles are often short lived and tend to recombine to form a non -plasma state of material. Thus, gas flows can be configured to move particles 610 quickly, such that particles 610 are able etch debris material 614 before recombining. Gas flows prevent redeposition of new chemical 616.

[0089] The etching rate of plasma 608 can depend on several factors, such as the density of plasma 608, the chemical reactions that occur during etching, the pressure in an etching environment, and the temperature of the etching environment. Etching rates can range from about 0.1 nanometer (nm) / min to about 200 nm / min. In some aspects, etching rates can be controlled to correspond to deposition rates in the vessel or the / exhaust module.

[0090] In some aspects, etching component 602 is configured to generate plasma at an operating pressure of a radiation generation chamber (e.g., vessel 502) and / or exhaust module (e.g., exhaust module 504). A radiation generation chamber can be held at atmospheric pressure, or in a vacuum (i.e., a pressure below atmospheric pressure). The vessel or the exhaust module can be held at a pressure optimal for EUV light generation, for example, 0.5-2 Torr.

[0091] FIGS. 7A, 7B, 7C, 7D, and 7E show examples of plasma generation technologies, according to some aspects. Any of the plasma generation technologies disclosed herein can be integrated into an etching component, as described in reference to FIGS. 5, 6A, and 6B.

[0092] FIG. 7A shows an schematic of inductively coupled plasma generation, according to some aspects. During inductively coupled plasma generation, a power supply 702 can apply a time -varying current to a coil 704. The time -varying current can induce a time -varying magnetic field, which can then induce an alternating electric field in region 706 (i.e., the region at the center of coil 704). Electrons in a gas in region 706 can be energized by the alternating electric field and collide with gas molecules to create plasma 708. While plasma 708 is often generated inside region 706, gas flows 710 can direct the plasma towards a surface 712. Surface 712 can include a surface of an exhaust pathway or liner as described in reference to FIG. 5.

[0093] FIGS. 7B and 7C show schematics of capacitively coupled plasma generation, according to some aspects. A capacitivley coupled plasma 714 can be generated by an etching component 716. Etching component 716 can comprise a set of electrodes 718. In some aspects, a liner (e.g., liners 516a- c in Fig. 5), an exhaust passthrough, an exhaust transition, and / or a contaminant passageway serves as one electrode of set of electrodes 718. A power supply 720 can supply an alternating voltage across electrodes 718, thereby generating an alternating electric field in region 722. The electric field can energize electrons in a gas, which can collide with other gas molecules to create plasma 714.

[0094] In the example shown in FIG. 7C, electrodes 718 are asymmetrically mounted on opposite sides of a dielectric material 724. When an alternating voltage is applied to electrodes 718, a discharge can occur in region 725. The discharge can supply enough energy to create both a plasma 714 and a force 726. Force 726 can spread plasma 714 across upper surface 727 of dielectric material 724.

[0095] In some aspects, the time varying current described in reference to FIG. 7A and the alternating voltage described in reference to FIGS. 7B and 7C have a frequency in the radiofrequency range of the electromagnetic spectrum, which can extend from around 3 kilohertz to around 300 MegaHertz.

[0096] FIG. 7D shows a schematic of a microwave plasma generation, according to some aspects. An etching component 728 can include a micro wave launcher 730 and an insulating window 732. Microwave launcher 730 can supply radiation 734, which can exit etching component 728 through insulating window 732. Insulating window 732 can include quartz orthe like. In some aspects, the space 736, between microwave launcher 730 and window 732 can be held at a vacuum.

[0097] In some aspects, radiation 734 can collide with gas atoms and molecules as it exits window 732 to produce plasma 738. Plasma 738 can have a critical density threshold. If a plasma has a density below the critical density threshold, radiation can penetrate and sustain the plasma. Alternatively, when the critical density threshold of a plasma has been reached, input radiation can propagate along the surface 742 and ionize additional particles to create plasma 743.

[0098] FIG. 7E shows a schematic of electron cyclotron resonance (ECR) plasma generation, according to some aspects. A plasma 744 can be generated by etching component 746. Etching component 746 can include a microwave source 748 and one or more magnets 750.

[0099] In some aspects, etching component 746 can generate plasma 744 through resonance between cyclotron motion of electrons in a gas and incoming electromagnetic radiation. For example, one or more magnets 750 can apply a magnetic field that causes free electrons in the gas to rotate at a cyclotron frequency. Microwave source 748 can produce radiation 752, which, when introduced to the gas at a frequency approximately equal to the cyclotron frequency, can cause a resonating effect. The resonating effect can cause heating, which can lead to partial ionization of the gas, thus producing plasma 744.

[0100] FIGS. 8A, 8B, and 8C show example configurations of etching components in a light source, according to some aspects.

[0101] FIG. 8A shows an example of a capacitivley coupled etching component integrated into a liner of a vessel in a light source, according to some aspects. A liner 802 can have a wall 804 with an innersurface 806 and an outer surface 808. Liner 802 can be a first liner coupled to an exhaust module, a second liner positioned between the first liner and a cap structure of the vessel, or a third liner positioned between the second liner and a collector mirror in the vessel. Inner surface 806 faces a plasma generation region, and thus is susceptible to contamination by source material debris. An inner region of wall 804 can include cooling components 810. Cooling components 810 can comprise cooling fluid lines or the like.

[0102] In some aspects, an etching component 812 can be placed adjacent to outer surface 808. Etching component 812 can contain an electrode 814 to which power is supplied via power source 816. Outer surface 808 can be grounded. As described in reference to FIG. 7B, a plasma 818 can be generated in a region between electrode 814 and outer surface 808. In some aspects of the present invention, outer surface 808 can be coated such that plasma ions have a lower probability of recombining before reaching inner surface 806.

[0103] In some aspects, one or more channels 820 are constructed through wall 804 to direct plasma 818 towards inner surface 806, where the ions and / or radicals contained in plasma 818 react with and remove source material debris through an etching process.

[0104] While FIG. 8 A only shows one etching component 812, it can be understood that multiple etching components 812 can be integrated into the liner and / or exhaust module of a light source in a similar manner.

[0105] FIG. 8B shows an example of a plurality of capacitively charged etching components integrated into an exhaust module 822 coupled to a vessel 823, according to some aspects. Exhaust module 822 can contain an exhaust transition 824, an exhaust passthrough 825, a contaminant passageway 826, and a scrubber 828.

[0106] Similar to liner 802 in Fig. 8A, exhaust transition 824 and contaminant passageway 826 have walls 830 with inner surfaces 832 and outer surfaces 834. Wall 830 can be cooled via cooling lines (not shown) or the like.

[0107] In some aspects, etching components 836 can be placed adjacent to outer surfaces 834. Each etching component 836 can comprise an electrode 838 to which power is suppled via a power source 839. Outer surfaces 834 can be grounded, thus allowing plasma 840 to from in spaces between electrodes 838 and outer surfaces 834. Plasma 840 can include ions and / or radicals that can be directed into exhaust module 822 via the funnel like shape of the walls 830.

[0108] FIG. 8C shows an example of a plurality of antenna-like etching components integrated into a surface, according to some aspects. An antenna-like etching component 842 can contain plasmagenerating components (not shown). For example, etching component 842 can contain any of the components described in reference to FIGS. 7A-7E.

[0109] In some aspects, etching component 842 can be integrated into a wall 844 of a chamber, liner, and / or exhaust module in a light source. Wall 844 can include an inner surface 846 and an outer surface 848. Source material debris can deposit on inner surface 846. A first end 852 of etching component 842can protrude through inner surface 846, such that generated plasma 850 can spread across inner surface 846. A second end 854 of etching component 842 can be located inside of wall 844, and, in some aspects, can extend to outer surface 848. Power components 856 and cooling components 858 can be routed to the second end 854 of etching component 842 through the inside of wall 844 or along outer surface 848.

[0110] While not shown in FIG. 8C, it can be understood by a person of ordinary skill in the art that etching component 842 can be located in alternative positions relative to wall 844. For example, in one aspect, all of etching component 842 can protrude from outer surface 846. In another aspect, etching component 842 can be suspended above outer surface 846. Etching component 842 can also be located in a region separate from wall 844. In this embodiment, plasma 850 can be routed to inner surface 846, though, for example, a channel or via gas flows.[oni] In some aspects, multiple etching components 842 are located in a light source. Multiple etching components 842 can be spaced such that plasma 850 interacts with desired regions of inner surface 846. For example, etching components 842 can be spaced such that plasma 850 generated by each etching component overlaps, thus providing continuous coverage. Etching components 842 can also be spaced such that gas flows 860 spread plasma 850 into a region between the etching components.

[0112] FIG. 9 shows a flowchart of an example method 900, according to some aspects. In some implementations, method 900 can be used for cleaning surfaces in a light source of a lithography apparatus. It is to be appreciated that not all operations may be needed to perform the disclosure provided herein. Furthermore, some of the operations may be performed simultaneously, or in a different order than the one shown in FIG. 9 as will be understood by a person of ordinary skill in art.

[0113] In operation 902, a controlled flow of gaseous material can be introduced into a cavity.

[0114] In operation 904, the gaseous material can be ionized to form a plasma state. The plasma state of the gaseous material can comprise ions and radicals. One or more etching components, as described in FIGS. 7A-7E and 8A-8C can generate the plasma state of the gaseous material.

[0115] In operation 906, the ions and radicals in the plasma state of the gaseous material can interact with a contaminant material on a surface of an exhaust module to form contaminant material -containing molecules.

[0116] In operation 908, the contaminant material -containing molecules can be removed from a light source through the exhaust module. The exhaust module can be coupled to a liner of an extreme ultraviolet light source, as described in reference to FIG. 5. In some aspects, configured gas flows may remove the contaminant material -containing molecules. FIG. 10 shows a flowchart 1000, according to some aspects. Flowchart 1000 can detail the operational and maintenance stages during which a light source can be cleaned using one or more etching components.

[0117] In some aspects, flowchart 1000 can include an exposure mode 1002 and a dark mode 1004. During exposure mode 1002, a light source can produce exposure radiation. In some aspects, a light source does not generate radiation continuously during exposure mode 1002. For example, the lightsource can cycle between a hit mode 1006, wherein laser pulses are configured to irradiate source material to create plasma, and a miss mode 1008, wherein laser pulses are configured to miss the source material. The cycling between hit mode 1006 and miss mode 1008 can be rapid. For example, hit mode 1006 can last up to hundreds of milliseconds while miss mode 1008 can last tens to hundreds of milliseconds.

[0118] During dark mode 1004, the light source does not produce exposure radiation, according to some aspects. Dark mode 1004 can describe the time between exposures, for example, when wafers are exchanged. Additionally, dark mode 1004 can describe a time when the light source is turned off, such as during scheduled maintenance.

[0119] A cleaning mode 1010 can be activated at various times during exposure mode 1002 and dark mode 1004. During cleaning mode 1010 a plasma state of material can be generated by one or more etching components in a chamber and / or exhaust module of a light source, as described in reference to FIGS. 6A-6B, 7A-7E, and 8A-8C above.

[0120] Etching plasmas can most effectively generate radicals and ions when there are none otherwise present in an EUV light source. Furthermore, it is known in the art that etch rates can depend on the temperature of a surface to be etched, with the etch rate decreasing as temperature increases. Accordingly, desired conditions for plasma etching can occur when EUV light is not actively being generated.

[0121] In one aspect, cleaning mode 1010 is activated during miss mode 1008 (e.g., between each EUV pulse).

[0122] In another aspect, cleaning mode 1010 is active during both hit mode 1006 and miss mode 1008. Cleaning mode 1010 can have a higher duty cycle during miss mode 1008 and a lower duty cycle during hit mode 1006.

[0123] In another aspect, cleaning mode 1010 is active between EUV exposures during dark mode 1004.

[0124] In another aspect, cleaning mode 1010 can be activated during planned maintenance and diagnostics. In some aspects, a dedicated etching time can be defined during dark mode 1004.

[0125] Some regions of a light source can activate cleaning mode 1010 more frequently than other portions of the light source. For example, areas with higher levels of source material deposition can be cleaned more often than areas with lower rates of source material deposition.

[0126] The terms “radiation,” “beam,” “light,” “illumination,” or the like can be used herein to refer to one or more types of electromagnetic radiation, for example, ultraviolet (UV) radiation (for example, having a wavelength X of 365, 248, 193, 157 or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (for example, having a wavelength in the range of 5-100 nm such as, for example, 13.5 nm), or hard X-ray working at less than 5 nm, as well as particle beams, such as ion beams or electron beams. Generally, radiation having wavelengths between about 400 to about 700 nm is considered visible radiation; radiation having wavelengths between about 780-3000 nm (or larger) is considered IRradiation. UV refers to radiation with wavelengths of approximately 100-400 nm. Within lithography, the term “UV” also applies to the wavelengths that can be produced by a mercury discharge lamp: G- line 436 nm; H-line 405 nm; and / or, I-line 365 nm. Vacuum UV, or VUV (i.e., UV absorbed by gas), refers to radiation having a wavelength of approximately 100-200 nm. Deep UV (DUV) generally refers to radiation having wavelengths ranging from 126 nm to 428 nm, and in some aspects, an excimer laser can generate DUV radiation used within a lithographic apparatus. It should be appreciated that radiation having a wavelength in the range of, for example, 5-20 nm relates to radiation with a certain wavelength band, of which at least part is in the range of 5-20 nm.

[0127] Although some aspects of the present disclosure are described in the context of lithographic apparatuses in the manufacture of ICs, it should be understood that lithographic apparatuses described herein can be used in other applications, for example, in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat -panel displays, UCDs, thin-fdm magnetic heads, etc. Those skilled in the art will appreciate that, in the context of such alternative applications, any use of the terms “wafer” or “die” herein can be considered as specific examples of the more general terms “substrate” or “target portion”, respectively. A substrate can be processed before or after exposure in, for example, a track unit (a tool that typically applies a layer of resist to a substrate and develops the exposed resist) and / or a metrology unit. Where applicable, aspects disclosed herein can be applied to such and other substrate processing tools. Furthermore, a substrate can be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein can also refer to a substrate that already contains multiple processed layers.

[0128] Furthermore, although some aspects of the present disclosure are described in the context of optical lithography, it should be understood that aspects of the present disclosure are not limited to optical lithography. For example, in imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device can be pressed into a layer of resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.

[0129] It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by those skilled in relevant art(s) in light of the teachings herein.

[0130] The present disclosure has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. The foregoing description of specific aspects will so fully reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and / or adapt for various applications such specific aspects, without undue experimentation andwithout departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed aspects, based on the teaching and guidance presented herein.

[0131] It is to be understood that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections can set forth one or more, but not necessarily all, aspects of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way. The breadth and scope of the protected subject matter should not be limited by any of the above-described aspects, but should be defined in accordance with the following claims and their equivalents.

[0132] The embodiments can be further described using the following clauses:1. A light source including a vessel containing a first liner, wherein the first liner has a frustum shape; an exhaust module arranged adjacent to the first liner; an etching component arranged adjacent to the exhaust module; and a gas supply coupled to the etching component.2. The light source of clause 1 , wherein the exhaust module includes an exhaust transition coupled to the liner through an exhaust passthrough; a gas cooler; a scrubber positioned between the exhaust transition and the gas cooler; and a contaminant passageway comprising a first portion positioned between the exhaust transition and scrubber and a second portion positioned after the gas cooler.3. The light source of clause 1, wherein the etching component produces plasma comprising radicals and ions configured to remove tin-containing debris.4. The light source of clause 1, wherein the etching component includes at least one antenna.5. The light source of clause 2, wherein the etching component is located on a surface of the exhaust passthrough.6. The light source of clause 2, wherein the exhaust passthrough is free of a heating component.7. The light source of clause 2, wherein the etching component is located in at least one of the first portion of the contaminant passageway and the second portion of the contaminant passageway.8. The light source of clause 1, further including a collector mirror positioned on a first end of the vessel, a conical structure positioned on a second end of the vessel, and a second liner positioned between the conical structure and the first liner, wherein the etching component is located on an inner wall of the second liner.9. The light source of clause 7, further including a third liner positioned between the collector mirror and the first liner, wherein the etching component is located on an inner wall of the third liner.10. The light source of clause 1, further including a controller configured to activate the etching component at least one of: in between extreme ultraviolet (EUV) pulses, in between EUV exposures, during a dedicated time when an EUV is not generated, and continuously during the EUV is generated, wherein higher power is supplied to the etching component in between EUV bursts and lower power is supplied to the etching component during EUV bursts.11. The light source of clause 1, wherein at least one of the exhaust passthrough, the exhaust transition, and the contaminant passage way is configured to operate at a temperature below a tin melting point.12. The light source of clause 1, wherein the EUV light source includes at least two etching components and at least one of the etching components is located on the first liner.13. A method including introducing a controlled flow of gaseous material into a cavity; ionizing the gaseous material to form a plasma state, wherein the plasma state of the gaseous material comprises ions and radicals; interacting the ions and radicals with a contaminant material on a surface of an exhaust module to form a contaminant material -containing molecules; and removing the contaminant materialcontaining molecules through the exhaust module, wherein the exhaust module is coupled to a liner of an extreme ultraviolet (EUV) light source.14. The method of clause 13, wherein removing the contaminant material -containing molecules including etching source material debris via interaction with ions and / or radicals in the plasma state of the material.15. The method of clause 13, wherein generating ionizing the gaseous material comprising electromagnetically inducing an electric current in the gaseous material.16. The method of clause 13 , further including maintaining a temperature of at least one component of the exhaust module below a melting point of the contaminant material during ionizing.17. The method of clause 13, wherein ionizing the gaseous material occurs between EUV pulses and / or between EUV exposures.18. The method of clause 13, wherein ionizing the gaseous material occurs when an EUV light source is not generated.19. A lithography apparatus including an extreme ultraviolet (EUV) light source having a vessel containing a liner; an exhaust transition coupled to the liner; and an etching component configured to remove tin debris from the liner and / or the exhaust passthrough, and wherein the etching component comprises a microwave plasma antenna, a surface wave plasma antenna, or an electron cyclotron resonance antenna.20. The lithography apparatus of clause 19, wherein the etching component is embedded in an inner surface of the exhaust passthrough.

Claims

CLAIMS1. A light source comprising: a vessel containing a first liner, wherein the first liner has a frustum shape; an exhaust module arranged adjacent to the first liner; an etching component arranged adjacent to the exhaust module; and a gas supply coupled to the etching component.

2. The light source of claim 1, wherein the exhaust module comprises: an exhaust transition coupled to the liner through an exhaust passthrough; a gas cooler; a scrubber positioned between the exhaust transition and the gas cooler; and a contaminant passageway comprising a first portion positioned between the exhaust transition and scrubber and a second portion positioned after the gas cooler.

3. The light source of claim 1, wherein the etching component produces plasma comprising radicals and ions configured to remove tin-containing debris.

4. The light source of claim 1, wherein the etching component comprises at least one antenna.

5. The light source of claim 2, wherein the etching component is located on a surface of the exhaust passthrough.

6. The light source of claim 2, wherein the exhaust passthrough is free of a heating component.

7. The light source of claim 2, wherein the etching component is located in at least one of the first portion of the contaminant passageway and the second portion of the contaminant passageway.

8. The light source of claim 1, further comprising a collector mirror positioned on a first end of the vessel, a conical structure positioned on a second end of the vessel, and a second liner positioned between the conical structure and the first liner, wherein the etching component is located on an inner wall of the second liner.

9. The light source of claim 7, further comprising a third liner positioned between the collector mirror and the first liner, wherein the etching component is located on an inner wall of the third liner.

10. The light source of claim 1, further comprising a controller configured to activate the etching component at least one of: in between extreme ultraviolet (EUV) pulses, in between EUV exposures, during a dedicated time when an EUV is not generated, and continuously during the EUV is generated, wherein higher power is supplied to the etching component in between EUV bursts and lower power is supplied to the etching component during EUV bursts.

11. The light source of claim 1, wherein at least one of the exhaust passthrough, the exhaust transition, and the contaminant passage way is configured to operate at a temperature below a tin melting point.

12. The light source of claim 1, wherein the EUV light source comprises at least two etching components and at least one of the etching components is located on the first liner.

13. A method comprising : introducing a controlled flow of gaseous material into a cavity; ionizing the gaseous material to form a plasma state, wherein the plasma state of the gaseous material comprises ions and radicals; interacting the ions and radicals with a contaminant material on a surface of an exhaust module to form a contaminant material -containing molecules; and removing the contaminant material -containing molecules through the exhaust module, wherein the exhaust module is coupled to a liner of an extreme ultraviolet (EUV) light source.

14. The method of claim 13, wherein removing the contaminant material-containing molecules comprising etching source material debris via interaction with ions and / or radicals in the plasma state of the material.

15. The method of claim 13 , wherein ionizing the gaseous material comprising electromagnetically inducing an electric current in the gaseous material.

16. The method of claim 13, further comprising maintaining a temperature of at least one component of the exhaust module below a melting point of the contaminant material during ionizing.

17. The method of claim 13, wherein ionizing the gaseous material occurs between EUV pulses and / or between EUV exposures.

18. The method of claim 13, wherein ionizing the gaseous material occurs when an EUV light source is not generated.

19. A lithography apparatus comprising: an extreme ultraviolet (EUV) light source comprising: a vessel containing a liner; an exhaust transition coupled to the liner; and an etching component configured to remove tin debris from the liner and / or the exhaust passthrough, and wherein the etching component comprises a microwave plasma antenna, a surface wave plasma antenna, or an electron cyclotron resonance antenna.

20. The lithography apparatus of claim 19, wherein the etching component is embedded in an inner surface of the exhaust passthrough.

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