Apparatus and method for supplying gas to lithographic system

Abstract

Degradation of reflectivity of one or more reflective optical elements in a system for generating EUV radiation is reduced by introducing a small amount of a first gas into a vacuum chamber containing the optical elements, wherein the first gas is separated from an initial gas, such as a CDA or XCDA. The first gas may be added to another gas stream, such as hydrogen.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to European application 63 / 392,208 filed on July 26, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to systems for the production of radiation for lithography systems. Such systems typically use reflective optical elements arranged in a vacuum environment. The process of generating and controlling extreme ultraviolet (EUV) radiation in such systems tends to reduce the reflectivity of these optical elements over time. An example of such an environment is a vacuum chamber of an EUV source, in which a plasma is generated by discharge or laser ablation of a target or source material. In this application, optical elements are used, for example, to collect and direct radiation for use outside the chamber (but still in a vacuum), such as for semiconductor lithography. Another example is a vacuum chamber housing optics for a projection system for such an apparatus. Background Art

[0004] EUV, eg, electromagnetic radiation having a wavelength of about 50 nm or less (sometimes also called soft x-rays), and including radiation with a wavelength of about 13.5 nm, can be used in lithography processes to create extremely small features in substrates such as, for example, silicon wafers.

[0005] Some methods for generating EUV radiation include converting a target material (also referred to as a source material) from a liquid state to a plasma state. The target material preferably includes at least one element, such as xenon, lithium, or tin, that has one or more emission lines in the EUV range. In one such method, the laser produced plasma ("LPP") method, the desired plasma can be generated by irradiating a target material having the desired line-emitting element with a laser beam.

[0006] In more theoretical terms, an LPP source generates EUV radiation by depositing laser energy into a target material having at least one EUV emitting element, such as xenon (Xe), tin (Sn), or lithium (Li), thereby producing a highly ionized plasma with an electron temperature of tens of eV. One LPP technique involves generating a stream of droplets of target material and irradiating at least some of the droplets with pulses of laser radiation.

[0007] The energetic radiation generated during the deexcitation and recombination of these ions is emitted from the plasma in all directions. In one common arrangement, a near normal incidence mirror (often referred to as a "collector mirror" or simply a "collector") is positioned to collect, direct, and, in some arrangements, focus the radiation to a central location. The collected radiation can then be transferred from the central location to a set of scanner optics and ultimately to the wafer.

[0008] In the EUV part of the spectrum, it is generally considered necessary to use reflective optics for the collector and other EUV optics. At the wavelengths involved, the collector is advantageously implemented as a multilayer mirror ("MLM"). As the name implies, such an MLM is typically composed of alternating layers of material on a base or substrate.

[0009] The optical element must be placed in a vacuum chamber along with the plasma to collect and redirect EUV radiation. The environment within the chamber is harmful to the optical element, thereby limiting its useful life, for example, by reducing its reflectivity through any one or combination of several mechanisms. For example, the optical element within the environment may be exposed to energetic ions or particles of the target material, which may contaminate the exposed surface of the optical element. Particles of the target material may also cause physical damage and local heating of the optical element. The target material may specifically react with the material constituting at least one layer of the surface of the optical element. Even when using less reactive target materials, such as tin, indium or xenon, temperature stability, ion implantation and diffusion issues may need to be addressed. Blistering of the MLM coating must also be avoided. The target material may also be deposited on the surface of the optical element.

[0010] Despite these harsh conditions, there are techniques that can be used to increase the life of optical elements. For example, a cover layer can be placed on the optical element to protect the surface of the optical element. To make the cover layer more reflective, it can also have multiple spaced-apart layers to increase the reflectivity at the wavelength of the radiation to be reflected. However, such cover layers themselves are susceptible to damage through mechanisms such as reduction, hydrogen diffusion, and blistering.

[0011] In some systems, molecular hydrogen (H2) gas at a pressure in the range of about 0.5 mbar to about 3 mbar is used in the vacuum chamber for slowing down the target material fragments. Hydrogen is relatively transparent to EUV radiation having a wavelength of about 13.5 nm. H2 gas is introduced into the vacuum chamber to slow down the high-energy fragments (ions, atoms and clusters) of the target material generated by the plasma by collisions with the gas molecules. For this purpose, a flow of H2 gas is used, which may also be opposite to the trajectory of the fragments. This flow is used to reduce damage from deposition, implantation and sputtering of the target material on the optical coating of the optical element.

[0012] In addition to hydrogen, small amounts of other gases may be introduced into the chamber to extend the life of the optics within the chamber. Which non-hydrogen gas is used generally depends on the chemical composition of the outer layers of the optics, such as, for example, the cover layer of the MLM. However, it is possible that the facility in which the chamber is deployed may not have access to a ready supply of these non-hydrogen gases. It is in this context that the need for the present invention arises. Summary of the invention

[0013] A brief summary of one or more embodiments is given below in order to provide a basic understanding of those embodiments. This summary is not an extensive overview of all contemplated variations and is not intended to identify key or important elements of all embodiments, nor is it intended to set limitations on the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a condensed form as a prelude to a more detailed description presented later.

[0014] According to one aspect of an embodiment, a system for controlling the composition of a gas supplied to a portion of a lithographic device is disclosed, the system comprising: an inlet adapted to be connected to an initial gas source, the initial gas comprising a first gas component and a second gas component; a gas fractionator fluidically connected to the inlet and arranged to receive the initial gas, and the gas fractionator is adapted to produce a separation gas having a concentrated first gas component; and an outlet fluidically connected to the gas fractionator and arranged to receive the separation gas, and the outlet is adapted to be connected to be fluidically connected to the portion of the lithographic device to supply the separation gas to the portion of the lithographic device.

[0015] The first gas may include oxygen. The first gas may include nitrogen. The portion of the lithographic apparatus may include an extreme ultraviolet (EUV) light source. The portion of the lithographic apparatus may include a scanner. The initial gas may include clean dry air (CDA). The initial gas may include ultra clean dry air (XCDA).

[0016] The gas fractionator may include at least one membrane filter. The gas fractionator may include a multi-stage membrane filtration system comprising at least two membrane filters arranged in series. The gas fractionator may include at least one molecular sieve.

[0017] The initial gas may have a second gas concentration greater than 75% by volume, and the separated gas may have a second gas concentration less than 5% by volume.

[0018] The gas fractionator may include a dual cartridge molecular sieve, the dual cartridge molecular sieve including a first molecular sieve and a second molecular sieve. The second molecular sieve is not used when the first molecular sieve is being used, wherein the system further includes: a replacement condition sensing module, the replacement condition sensing module being arranged to sense a replacement condition in which the system switches from using the first cartridge to using the second cartridge; and a controller, the controller being connected to the replacement condition sensing module in a responsive manner and the controller being adapted to initially direct the initial gas through the first molecular sieve during a first time period, and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition.

[0019] The replacement condition may be at least one of the concentration of the first gas in the separated gas, the volume of the initial gas processed by the first filter cartridge, and the operation time of the first filter cartridge. The replacement condition sensing module may include: a first gas concentration sensor, the first gas concentration sensor being arranged to sense the concentration of the first gas in the separated gas and generate a signal indicating the concentration of the first gas in the separated gas; and the system may also include a controller, the controller being connected to the first gas concentration sensor in a responsive manner, and the controller being adapted to initially direct the initial gas through the first molecular sieve within a first time period, and switching to directing the initial gas through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0020] The system may further comprise a hydrogen delivery line arranged to deliver a hydrogen-containing gas into the portion of the lithographic apparatus, and wherein the outlet is in fluid communication with the hydrogen delivery line to inject the separation gas into the hydrogen delivery line.

[0021] According to another aspect of the embodiment, a lithography device including an extreme ultraviolet (EUV) light source system is disclosed, the lithography device including: a chamber, the chamber including a collector reflector; a hydrogen delivery line, the hydrogen delivery line being arranged to deliver a hydrogen-containing gas into the chamber; an inlet, the inlet being suitable for connecting to a source of an initial gas, the initial gas including a first gas component; a gas fractionator, the gas fractionator being fluidly connected to the inlet and being arranged to receive the initial gas and being suitable for at least partially separating the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; and an outlet, the outlet being fluidly connected to the gas fractionator and being arranged to receive the separated gas and being connected to the hydrogen delivery line in a fluidly connected manner to inject the separated gas into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

[0022] The first gas may include oxygen. The first gas may include nitrogen. The gas fractionator may include at least one membrane filter. The gas fractionator may include a multi-stage membrane filtration system, the multi-stage membrane filtration system including at least two membrane filters arranged in series. The gas fractionator may include at least one molecular sieve. The initial gas may have a second gas concentration greater than 75% by volume, and the separated gas may have a second gas concentration less than 5% by volume.

[0023] The gas fractionator may include a dual cartridge molecular sieve, the dual cartridge molecular sieve including a first molecular sieve and a second molecular sieve. The second molecular sieve is not used when the first molecular sieve is being used, and the system further includes: a replacement condition sensing module, the replacement condition sensing module being arranged to sense a replacement condition in which the system switches from using the first cartridge to using the second cartridge; and a controller, the controller being connected to the replacement condition sensing module in a responsive manner, and the controller is adapted to initially direct the initial gas through the first molecular sieve within a first time period, and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition. The replacement condition may be at least one of the concentration of the first gas in the separated gas, the volume of the initial gas processed by the first cartridge, and the operating time of the first cartridge.

[0024] The replacement condition sensing module may include a first gas concentration sensor, which is arranged to sense the concentration of the first gas in the separated gas and generate a signal indicating the concentration of the first gas in the separated gas, and the system may also include a controller, which is connected to the first gas concentration sensor in a responsive manner, and the controller is suitable for initially directing the initial gas through the first molecular sieve within a first time period, and switching to directing the initial gas through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0025] According to another aspect of an embodiment, a method for controlling the composition of a gas supplied to a portion of a lithography device is disclosed, the method comprising: supplying an initial gas, the initial gas comprising a first gas component; at least partially separating the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; and supplying the separated gas to the portion of the lithography device.

[0026] The first gas component may comprise primarily oxygen.The first gas component may comprise primarily nitrogen.The portion of the lithographic apparatus may comprise an extreme ultraviolet (EUV) light source portion.The portion of the lithographic apparatus may comprise a scanner.

[0027] Supplying the initial gas may include supplying clean dry air (CDA). Supplying the initial gas may include supplying extra clean dry air (XCDA).

[0028] The first gas component is at least partially separated using at least one membrane filter to produce the separated gas. The first gas component is at least partially separated using a multi-stage membrane filtration system including at least two membrane filters arranged in series to produce the separated gas.

[0029] At least partial separation of the first gas to produce a separated gas may be performed using at least one molecular sieve.

[0030] The initial gas may have a second gas concentration greater than 75% by volume, and the separated gas may have a second gas concentration less than 5% by volume.

[0031] The first gas component is at least partially separated using a dual cartridge molecular sieve including a first molecular sieve and a second molecular sieve to produce the separated gas. The second molecular sieve is not used when the first molecular sieve is being used, and the method further includes: sensing a replacement condition in which the system switches from using the first cartridge to using the second cartridge; and initially directing the initial gas through the first molecular sieve for a first time period, and switching to directing the initial gas through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0032] The replacement condition may be at least one of the concentration of the first gas in the separated gas, the volume of the initial gas processed by the first filter cartridge, and the operation time of the first filter cartridge. Sensing the replacement state may include: sensing the first gas concentration of the first gas in the separated gas and generating a signal indicating the concentration of the first gas in the separated gas; and initially directing the initial gas through the first molecular sieve for a first time period, and switching to directing the initial gas through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0033] Supplying the separation gas to the portion of the lithographic apparatus may comprise injecting the separation gas into a hydrogen delivery line arranged to supply a hydrogen containing gas to the portion of the lithographic apparatus.

[0034] According to another aspect of the embodiment, a method of controlling the composition of a gas supplied to an extreme ultraviolet (EUV) light source portion of a lithography device is disclosed, the method comprising: delivering a hydrogen-containing gas into a hydrogen delivery line, the hydrogen delivery line being arranged to deliver the hydrogen-containing gas to a chamber of the EUV light source, the chamber comprising a collector reflector; supplying an initial gas, the initial gas comprising a first gas component; at least partially separating the first gas component to produce a separated gas having a concentrated first gas component; and injecting the concentrated first gas component into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

[0035] The first gas component is at least partially separated using at least one membrane filter to produce the separated gas. The first gas component is at least partially separated using a multi-stage membrane filtration system including at least two membrane filters arranged in series to produce the separated gas. The first gas component is at least partially separated using at least one molecular sieve to produce a concentrated first gas component.

[0036] The initial gas may have a second gas concentration greater than 75% by volume, and the concentrated first gas component may have a second gas concentration less than 5% by volume.

[0037] The first gas component is at least partially separated using a dual cartridge molecular sieve including a first molecular sieve and a second molecular sieve to produce the separated gas. The method may also include: directing the initial gas through the first molecular sieve; sensing the concentration of the first gas in the separated gas and generating a signal indicating the concentration of the first gas in the separated gas; and stopping directing the initial gas through the first molecular sieve, and directing the initial gas through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0038] According to another aspect of the embodiment, an apparatus for generating a separation gas is disclosed, the apparatus comprising: an initial gas input device, the initial gas having a first oxygen concentration; a gas separator, the gas separator being fluidically connected to the initial gas input device and having a first mesh filter member and a second mesh filter member, the gas separator being arranged to separate the separation gas from the initial gas, the separation gas having a second oxygen concentration greater than the first oxygen concentration; an oxygen transfer line being fluidically connected to the gas separator; an oxygen sensor, the oxygen sensor being fluidically connected to the oxygen transfer line and being arranged to sense the oxygen concentration in the separation gas; and a controller. , the controller is capable of switching the gas separator between a first operating mode and a second operating mode, in which the gas separator uses the first mesh filter member but not the second mesh filter member to separate the separation gas from the initial gas, and in which the gas separator uses the second mesh filter member but not the first mesh filter member to separate the separation gas from the initial gas; and a gas control panel, the gas control panel is capable of adjusting the amount of oxygen from the oxygen transfer line to be transferred to the hydrogen transfer line, the hydrogen transfer line being arranged to transfer gas to the extreme ultraviolet radiation source. The initial gas may include clean dry air (CDA). The initial gas may include ultra clean dry air (XCDA).

[0039] The first filter element may include a first molecular sieve filter, and the second filter element may include a second molecular sieve filter. The apparatus may also include a flashback arrestor (FBA) on the oxygen delivery line downstream of the filter. The apparatus may also include an oxygen sensor positioned in the oxygen delivery line downstream of the gas separator.

[0040] The apparatus may further comprise a nitrogen transfer line adapted to transfer nitrogen from the gas separator. The apparatus may further comprise an exhaust line adapted to controllably exhaust the nitrogen transfer line and the oxygen transfer line. The controller or a further controller may be adapted to open and close the exhaust line.

[0041] Further embodiments, features, and advantages of the present invention, as well as the structure and operation of the various embodiments, are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate these embodiments and, together with the description, further serve to explain the principles of these embodiments and enable those skilled in the relevant art to make and use these embodiments.

[0043] Figure 1is a not-to-scale diagram of the overall broad concept for an EUV lithography system.

[0044] Figure 2A is a partial perspective, not-to-scale, illustration of optical components and a gas flow system for an EUV lithography system.

[0045] Figure 2B is a not-to-scale illustration of the optical components and gas flow system for an EUV lithography system.

[0046] Figure 3 is a not-to-scale diagram of a general broad concept of a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0047] Figure 4 is a not-to-scale diagram of another general broad concept of a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0048] Figure 5 is a not-to-scale diagram of another general broad concept of a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0049] Figure 6 is a not-to-scale diagram of a gas fractionator of a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0050] Figure 7 is a not-to-scale diagram of another gas fractionator of a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0051] Figure 8 is a flow chart of a method of adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0052] Fig. 9 is a flow chart of a method of operating a gas fractionator in a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0053] Fig.10 is a flow chart of a method of operating a gas fractionator in a system for adding a first gas to a chamber in an EUV lithography system according to aspects of the embodiments.

[0054] The structure and operation of the various embodiments of the present invention and the advantages and features of the present invention are described in detail below with reference to the accompanying drawings. These embodiments are presented herein for illustrative purposes only. Based on the teachings contained in the present invention, those skilled in the relevant art will understand additional embodiments. DETAILED DESCRIPTION

[0055] Various embodiments are now described with reference to the accompanying drawings, wherein the same reference numerals are used throughout to refer to the same elements. In the following description, for the purpose of explanation, many specific details are set forth to facilitate a thorough understanding of one or more embodiments. However, it may be apparent in some or all cases that any of the embodiments described below may be practiced without adopting the specific design details described below. In other examples, known structures and devices are shown in block diagram form to facilitate description of one or more embodiments. In the following description and claims, terms such as "upper", "lower", "top", "bottom", "vertical", "horizontal" may be used. These terms are intended to show only relative orientation, rather than any orientation relative to gravity, unless otherwise indicated or clear from the context.

[0056] Figure 1 1 is a schematic diagram of an example of an EUV radiation source (e.g., a laser-generated plasma EUV radiation source 100) according to one aspect of an embodiment of the present invention. As shown, the EUV radiation source 100 may include a pulsed or continuous laser source 122, which may be, for example, a pulsed gas discharge CO2 laser source that generates a 10.6 μm or 1 μm radiation beam 112. The pulsed gas discharge CO2 laser source may have a DC or RF excitation that operates at high power and high pulse repetition rate.

[0057] The EUV radiation source 100 also includes a target delivery system 124 for delivering a target material in the form of droplets or a continuous stream. In this example, the target material is a liquid, but it can also be a solid or a gas. In the following description, tin is used as a non-limiting example of a target material, and it should be understood that other materials can be used. In addition, droplets are used as a non-limiting example of the form of tin, and it should be understood that other forms can be used.

[0058] In the depicted system, a target material delivery system 124 introduces droplets 114 of a target material into the interior of a vacuum chamber 126 having chamber walls 127. The vacuum chamber 126 includes an irradiation zone 128 in which the target material can be irradiated to produce a plasma. It should be noted that, as used herein, an irradiation zone is a zone where irradiation of a target material can or is intended to occur, and is an irradiation zone even when no irradiation actually occurs. The EUV light source may also include a beam steering system 132.

[0059] In the system shown, the components are arranged so that the droplets 114 travel substantially horizontally. The direction from the laser source 122 toward the irradiation zone 128, i.e., the nominal propagation direction of the beam 112, can be referred to as the z-axis. The path taken by the droplets 114 from the target material delivery system 124 to the irradiation zone 128 can be referred to as the x-axis. Figure 1 The view is thus perpendicular to the XZ plane. Although a system in which droplets 114 travel substantially horizontally is depicted as an example, one of ordinary skill in the art will appreciate that other arrangements may be used in which droplets travel vertically or at an angle relative to gravity in a range between and including 90° (horizontal) and 0° (vertical).

[0060] The EUV radiation source 100 may also include an EUV light source controller system 160 and a laser emission control system 165. The EUV radiation source 100 may also include a detector, such as a target position detection system 170, which generates an output indicating an absolute or relative position of a target droplet, for example relative to the irradiation zone 128, and provides the output to a target position detection feedback system 162.

[0061] like Figure 1 1 , the target material delivery system 124 may include a target delivery control system 190. The target delivery control system 190 adjusts the path of the target droplets 114 through or around the irradiation zone 128. For example, the adjustment can be achieved by repositioning the point at which the droplet generator 192 releases the target droplet 114. The droplet release point can be repositioned, for example, by tilting the droplet generator 192 or by translating the droplet generator 192 laterally. The droplet generator 192 extends into the chamber 126 and is preferably supplied with the target material from the outside. A gas source (not shown) places the target material under pressure in the droplet generator 192. Droplets 114 that pass through the irradiation zone 128 without being converted continue to the target material container 134.

[0062] Continue to refer to Figure 1 , the radiation source 100 may also include one or more optical elements. In the following description, the collector 130 is used as an example of such an optical element, but the description also applies to other optical elements. The collector 130 may be a normal incidence reflector implemented, for example, as a multilayer mirror. The collector 130 may be in the form of an oblong ellipsoid having a central hole 135 to allow the laser radiation 112 to pass through and reach the irradiation zone 128. The collector 130 has a first focus at the irradiation zone 128 and a second focus at a so-called intermediate point 140 (also referred to as intermediate focus 140), where EUV radiation can be output from the EUV radiation source 100 and input to, for example, an integrated circuit lithography scanner 150.

[0063] The integrated circuit lithography scanner 150 includes a projection system (e.g., a refractive or reflective projection lens system) 156, also referred to as a projection optics box or POB, that is configured to project a pattern (e.g., a mask) imparted to a radiation beam by a patterning device 154 onto a target portion (e.g., comprising one or more dies) of a substrate 152. The substrate 152 is then further processed in a known manner to fabricate integrated circuit devices.

[0064] As mentioned above, hydrogen may be introduced into the chamber 126 to mitigate debris contamination. However, typically, for example, where tin or plasma is used in the chamber 126, the environment in the chamber 126 and projection system 156 is intended to be as clean as possible (lowest possible levels of other gases such as oxygen, nitrogen, H2O, etc.) to reduce any risk of oxidation or unwanted chemical reactions, as these may cause collector degradation. In addition, oxygen may undesirably cause oxidation of other components in the vacuum chamber 126 (such as the nozzle of the droplet generator 192), for example.

[0065] However, it has been determined that the presence of low levels of gases in the chamber atmosphere (which would otherwise be considered impurities) can have a positive effect on maintaining or enhancing the performance (e.g., reflectivity and lifetime) of optical elements in the chamber. Therefore, it is potentially advantageous to intentionally supply controlled amounts of such one or more gases, or mixtures of such gases, into a vacuum chamber, such as a source or projection system. These gases can be supplied, for example, in the form of an air mixture (air, clean dry air (CDA) or ultra clean dry air (XCDA)) or mixed with a rare or inert gas (e.g., argon).

[0066] As mentioned, one of the gases that may be beneficial at low concentrations is oxygen. Oxygen will be used as an example of a non-hydrogen first gas introduced into the chamber, but it will be understood that another gas, such as nitrogen, may be used depending on the chemical composition of the exposed surfaces of the optical components in the chamber.

[0067] One method of adding oxygen to a vacuum chamber is to discharge the oxygen into the hydrogen stream entering the vacuum chamber. For example, oxygen can be added to a vacuum chamber by adding oxygen to a hydrogen stream passing near a collector to increase the local concentration of oxygen to a level that stabilizes the collector blanket without consuming significant amounts of H* in a water-gas reaction or oxidizing critical components in the chamber.

[0068] However, there are engineering risks and challenges associated with using oxygen. Using pure oxygen facilities, such as oxygen facility supply lines or compressed bottled oxygen, can incur significant costs and raise significant safety issues. Retrofitting installed EUV tools to use such pure oxygen facilities can result in extended downtime for these tools and significant changes to the gas supply infrastructure, especially for facilities that do not already have pure O2 facilities.

[0069] The above discussion is primarily about reflective optics located in the source vacuum chamber. The beneficial effects of adding a mitigating gas to the gas mixture in the vacuum chamber also extend to reflective EUV optics located in other parts of the system, such as reflective optical elements in the POB. For example, a mitigating gas can be added to the gas mixture in the vacuum chamber of the POB to inhibit etching of the surfaces of the reflective optical elements located there and to mitigate the formation of SiH4. More specifically, the pattern forming device 154 is also in a vacuum environment, which is sometimes referred to as a reticle stage or reticle microenvironment. A low concentration of a gas such as oxygen can be added here to mitigate the formation of SiH4.

[0070] In the source, for at least some applications, it is desirable to establish a flow of the hydrogen / oxygen gas mixture to flow over at least a portion of the surface of the EUV reflective optic (i.e., adjacent to and having a velocity component parallel to the at least a portion). This can be achieved, for example, by adding an outlet to the system for flowing hydrogen in the chamber and then adding oxygen to the hydrogen flow. As mentioned above, the collector 130 can be in the form of an oblong ellipsoid with an aperture 135 to allow the laser radiation to pass through and reach the irradiation zone 128. This is in Figure 1 , Figure 2A and Figure 2B A hole 135 extends through the reflective surface 200 of the collector reflector 130. The hole 135 is located on the axisymmetric line A of the collector 130. The tubular body 210 extends through the hole 135. The frustoconical element 220 surrounds the tubular body 210 and is spaced apart from the tubular body 210 to define a gap 230 therebetween.

[0071] The word "tubular" will be understood by those skilled in the art as a broad term that may encompass or be synonymous with a variety of different structures. For example, the tubular body may not have parallel walls, but may be conical or flared. The tubular body may be any structure that forms a conduit from one side of the collector (e.g., a non-collecting surface) to the other opposite side of the collector (e.g., a collecting surface). The tubular body may have a circular cross-section or an elliptical cross-section or any other suitable cross-section.

[0072] In use, the primary airflow is directed through the tubular body 210, which in this embodiment is constructed and arranged to direct the airflow in a direction transverse to the reflective surface 200. This flow is known as a cone flow and is composed of Figure 2B 200 and 210. The conical flow CF is generally directed toward one or both of the first and second focal points. The tubular body 210, together with the gap 230 between the frustoconical elements 220 surrounding the tubular body 210 and the outlet 250, is arranged in a circumferential flow ring 240 to direct the airflow substantially along the reflective surface 200 and away from the tubular body 210, as shown. This flow is referred to as an umbrella-shaped cone flow or simply an umbrella-shaped flow. Figure 2B The flow from the circumference toward the center along the surface of the collector 130 can be called peripheral flow. Figure 2B The PF is marked in the figure.

[0073] The rate of the cone flow of hydrogen can be in the range of about 50 SLM to about 165 SLM. The rate of the umbrella cone flow of the hydrogen mixture can be in the range of about 40 SLM to about 90 SLM. The rate of the peripheral flow of the hydrogen mixture can be in the range of about 60 SLM to about 160 SLM. Under these types of H2 flows, the oxygen flow is about 0.002 to about 0.8 SCCM. The total pressure in the chamber 126 can be in the range of about 1.2 mbar to about 2.2 mbar. Other flow rates and pressures can be used in other embodiments.

[0074] Alternatively, there may be a gas manifold system dedicated to flowing oxygen over the surface of the EUV reflective optics, with oxygen only being directed to holes / nozzles that flow gas along the surface of a local surface of the collector 30 (with a velocity component substantially locally parallel to said local surface).

[0075] Therefore, the presence of trace amounts of a first gas, such as oxygen or nitrogen, in a chamber of source or scanner optics in an EUV lithography system can extend the lifetime of the optics in the chamber. On the other hand, trace amounts of other gases in such an environment can reduce the lifetime of these optics, depending on the chemical composition of the exposed surfaces of these optics. For example, nitrogen can react with exposed surfaces of optics of a given chemical composition. For surfaces of other chemical compositions, the introduction of nitrogen can be beneficial, but the introduction of oxygen can be detrimental.

[0076] Using oxygen as the example of the first gas again, current photolithography tools may be installed in locations that lack oxygen facilities. Therefore, at such locations, the oxygen component of XCDA is used as an alternative pure oxygen as a supply gas to introduce oxygen into the gas in the chamber. This provides poor optical protection because other gases are present in XCDA, particularly about 78% by volume (volume ratio, N2 moles / XCDA moles), which participate in surface chemical reactions and plasma interactions. Therefore, reducing the amount of nitrogen in the XCDA gas mixture will prove to be beneficial.

[0077] According to aspects of the embodiments, these disadvantages are avoided by using XCDA or CDA supply gas as the oxygen source and separating out most of the nitrogen and injecting the low nitrogen content gas into the EUV source or scanner chamber. Using such a system, it is possible to reduce nitrogen from 78 volume % in the gas mixture upstream of the equipment to less than 5 volume % downstream, a reduction of 16 times or more, i.e., to 1 / 16 or less.

[0078] The apparatus can flow oxygen-rich / nitrogen-depleted gas into a container having a nitrogen concentration reduced to no more than 5% by volume without requiring gas supply infrastructure upgrades. Similarly, the apparatus can flow nitrogen-rich / oxygen-depleted gas into a container without requiring gas supply infrastructure upgrades. Thus, the system can be retrofitted in the field without significant downtime.

[0079] Figure 3 1 is a generally generalized, not-to-scale, diagram of a system 300 for adding oxygen to a chamber in an EUV lithography system according to aspects of an embodiment. The system 300 includes a hydrogen source 310. The hydrogen source 310 delivers hydrogen to various streams that reach the chamber 126 through an inlet, such as Figure 1 For example, the hydrogen source 310 supplies hydrogen to the peripheral flow system 330 through the hydrogen delivery line 340. Similarly, the hydrogen source 310 delivers hydrogen to the umbrella cone flow system 350 through the hydrogen delivery line 355. It will be understood that these delivery lines can be combined.

[0080] Also like Figure 3As shown in FIG. 3 , as part of the system 300 is a gas source 360. The gas source 360 ​​is, for example, a source of CDA or XCDA. The gas source 360 ​​supplies oxygen and nitrogen, labeled as first gas G1 and second gas G2, as the main components of CDA or XCDA, to a gas fractionator 370 via a pipeline 365. The gas fractionator 370 separates the oxygen component from the nitrogen component in the gas supplied to the gas fractionator 370. Here and elsewhere in the text, the term "component" is used to refer to the gases G1 and G2, which can be separated, for example, by conventional gas separation methods, with a purity such as can be achieved by conventional gas separation methods. The oxygen component then passes downward through an oxygen pipeline 380.

[0081] exist Figure 3 In the example of FIG. 1 , the oxygen component then passes through a mixing node 320 to join the hydrogen delivered through a hydrogen delivery line 340, and reaches a mixing node 325 to join the hydrogen delivered to the umbrella cone flow system 350 through a line 355. The nitrogen component from the gas fractionator 370 travels along a discharge line 390 to a discharge device 395. Thus, in this system, oxygen is directed to the chamber as G1, and nitrogen is discharged as G2. It will be appreciated that the system can be configured so that nitrogen is directed to the chamber 126 as G1 and oxygen is discharged as G2. A controller 327 can be provided to control the amount of oxygen mixed into the hydrogen lines 340 and 355.

[0082] The system 300 as described above includes a flashback arrester (FBA) 385 between the gas fractionator 370 and the mixing nodes 320, 325, which is designed in a known manner to contain flashback and prevent it from propagating back into the upstream equipment. The system 300 also includes an exhaust line 397 that is controllably connected to the oxygen line 380 and the exhaust line 390 through the mixing nodes 398 and 399, respectively. For example, depending on the oxygen duty cycle input from the controller 327, the gas can be delivered to the exhaust line 397. It will be understood by those of ordinary skill in the art that systems such as the system 300 and other systems described herein will typically also include other conventional gas handling components, such as hoses, orifices, inlets, outlets, connectors, regulators, meters, sensors, valves, injection controls, bypass lines, exhausts, etc., as may be dictated by the requirements of a given design. Such components are typically commercially available.

[0083] Figure 4 is a not-to-scale diagram of an overall broad concept of a system 400 for adding a gas, such as oxygen, to a chamber in an EUV lithography system, according to aspects of the embodiments. Figure 4 The system 400 is similar to Figure 3The system 300 is shown in FIG. 1 , except that the hydrogen source 310 is arranged to provide hydrogen to the scanner optics 410 through the mixing node 420 .

[0084] Figure 5 is a not-to-scale diagram of an overall broad concept of a system 500 for adding a gas mixture to a chamber in an EUV lithography system, according to aspects of the embodiments. Figure 5 The system 500 is similar to Figure 3 System 300 and Figure 4 system 400 , except that the hydrogen source 310 is arranged to provide hydrogen to the peripheral flow system 330 , the umbrella cone flow system 350 , and the scanner optical device 410 .

[0085] Figure 6 is a not-to-scale diagram of a gas fractionator 370 of a system for adding oxygen to a chamber in an EUV lithography system, according to aspects of the embodiments. Figure 6 The gas fractionator 370 shown in FIG. 3 includes a first molecular sieve 610 and a second molecular sieve 620. Each of the first molecular sieve 610 and the second molecular sieve 620 can be implemented as a filter cartridge, in which case the combination of the sieves depicted can be regarded as a double filter cartridge configuration. According to aspects of the embodiment, these sieves are arranged so that only one of these sieves is used at a time. Which sieve is used at a given time is controlled by a controller 640 through control valves 650, 655, 660 and 665. The controller 640 performs this control according to a signal from a sensor 630 that detects the concentration of the added gas component flowing out of the gas fractionator 370. When the sensor 630 detects that the added gas concentration has dropped below a given threshold, indicating that the sieve being used at this time is exhausted, the controller 640 controls the valve to cut out the exhausted sieve, that is, to make it offline, and cut in another sieve, that is, to put it online. The exhausted sieve can then be allowed to regenerate itself or can be cut out without interrupting the operation of the gas fractionator 370.

[0086] The above are examples of systems and methods for detecting or sensing a change condition, which is a condition that indicates that the unit (filter cartridge or screen) currently in use has been exhausted and indicates the need to switch to using another unit. The above specific example is when the change condition is detected by sensing the gas concentration in the separated components of the gas. As the gas fractionator is used, this gas concentration will tend to decrease. When the gas concentration drops below a predetermined threshold, it is necessary or at least desirable to stop using the unit currently in use by taking the unit offline and then bringing the replacement unit online.

[0087] Another possible change condition is the total amount of supply gas that has been processed by the unit currently in use. Figure 3 The system 300 shown in Figure 4 The system 400 shown in Figure 5 The system 500 shown in FIG. Figure 6 and Figure 7 The system may be provided with a flow meter such as Figure 6 A flow meter 365 is provided that measures the volume of supply gas that has traveled to the screen in use and supplies a signal indicative of that volume to the controller 640, which can use the measurement to determine whether to initiate a swap of the active screen. Another possible swap condition can be the total operating time of the current active screen. For example, the controller 640 can track the total amount of time the active screen has been in use and can use that measurement to switch to an inactive screen.

[0088] Thus, the dual cartridge setup described above allows one sieve to be in operation while the other sieve is self-regenerating or being replaced. A dual cartridge molecular sieve filter capable of producing enough added gas to achieve the desired added gas dosage level in an EUV source or scanner may have a very small footprint - under a few inches in maximum dimension and weighing around 1 kg - and requires only enough power to separate nitrogen and oxygen from a CDA or XCDA or other air source. It is expected that a single unit will be sufficient to supply oxygen to multiple sources and scanner systems with only minimal changes to existing gas infrastructure.

[0089] Figure 7 is a not-to-scale diagram of another gas fractionator 370 ′ of a system for adding gas to a mixture in a chamber in an EUV lithography system, according to aspects of the embodiments. Figure 7 The gas fractionator 370' shown in FIG. 1 has N membrane separation filters 710, 720, ..., 730, which are used to separate oxygen from nitrogen in a known manner. It will be understood by those skilled in the art that one membrane gas separation filter may be used, or more than one gas membrane filter may be placed in series, wherein each gas membrane filter passes at least a portion of the separated gas to the next membrane filter in series until the desired oxygen concentration is reached.

[0090] Figure 7 Embodiments also use XCDA or CDA or even air as feed or supply gas, separate out most of the nitrogen, and inject the outlet low nitrogen content gas into the EUV source or scanner. The reduction of nitrogen is from 80% by volume in the gas mixture upstream of the equipment to less than 30% by volume downstream, a reduction of 2.5 times or more, i.e., a reduction to 1 / 2.5 or less.

[0091] A standard membrane filter module can also have a very small footprint, with its largest dimension being a few inches and weighing in the region of 1 kg, and requires no external power to separate nitrogen from the gas supplied by the supply source.

[0092] Figure 8 1 is a flow chart of a method of adding a first gas (such as oxygen) to a chamber in an EUV lithography system according to aspects of an embodiment. In step S100, an initial gas having a first gas component and a second gas component (e.g., nitrogen) is supplied to a system for generating a concentrated first gas. In step S110, the first gas component is separated from the initial gas. In step S120, the separated first gas is supplied to a source chamber or a scanner chamber. Figure 8 In the particular example shown in , the separated first gas component is injected into a hydrogen delivery line that supplies hydrogen to any of these chambers. Figure 8 The method is also applicable when another component (such as nitrogen) is separated from the initial gas.

[0093] Fig. 9 is a flow chart of a method of operating a gas fractionator in a system for adding a first gas to a chamber in an EUV lithography system to enable continuous operation according to aspects of an embodiment. Fig. 9 In the method shown in , in step S200, a first filter cartridge is used to separate the first gas component from a supply gas including a first gas component and a second gas. For example, the supply gas can be air, CDA or XCDA, the first gas component can be substantially oxygen, and the second gas component can be substantially nitrogen. When the first filter cartridge is used, there is monitoring of a replacement condition, the presence of which signals the need to stop using the first filter cartridge and switch to using the second filter cartridge instead. The replacement condition can be that the concentration of the first gas in the first gas component drops below a given threshold. The replacement condition can be that the maximum amount of supply gas that has been processed by the first filter cartridge since it was put into use is exceeded. The replacement condition can be that the maximum amount of time that the supply gas has been processed by the first filter cartridge since it was put into use is exceeded.

[0094] Therefore, in step S220, it is determined whether there is a replacement condition. If there is no replacement condition, when the process returns to step S200, the system continues to use the first filter cartridge to separate the first gas.

[0095] On the other hand, if it is determined in step S220 that a replacement condition exists, the system switches the gas flow through the gas fractionator to the second filter cartridge in step S230. In addition, at that time, or at any time before the second filter cartridge is exhausted, the first filter cartridge can be replaced or allowed to self-regenerate. Next, in step S240, the second filter cartridge is used to separate the first gas. In step S260, it is determined whether there are conditions for replacing the second filter cartridge. Similarly, the replacement condition can be, for example, the concentration of the first gas in the first gas component drops below a given threshold. The replacement condition can be exceeding the maximum amount of supply gas that has been processed by the second filter cartridge since it was put into use. The replacement condition can be exceeding the maximum amount of time that the supply gas has been processed by the second filter cartridge since it was put into use.

[0096] If it is determined in step S260 that there is no replacement condition, the system continues to use the second filter cartridge to separate the first gas. On the other hand, if it is determined in step 260 that the first gas concentration is below the predetermined threshold, the system switches the flow to the first filter cartridge, which has been replaced or regenerated at this time and is a functionally fresh filter cartridge, in step S270. At this time or at a later time before the first filter cartridge has been exhausted, the operator replaces the second filter cartridge unless the system is a system in which the filter cartridge can be self-regenerated.

[0097] It should be understood that steps S220 and S260 may be performed substantially continuously by the control system.

[0098] Fig.10 is a flow chart of a method of operating a gas fractionator in a system for adding oxygen to a chamber in an EUV lithography system to enable continuous operation according to aspects of an embodiment. Fig.10 The method shown in is similar to Fig. 9 The method shown in , wherein the concentration of the first gas in the first gas component is a specific example of the replacement condition. Fig.10 In the method shown in , in step S200, a first gas component is separated from a supply gas including a first gas component and a second gas component using a first filter cartridge. While using the first filter cartridge, a first gas concentration of the gas that has been processed by the first filter cartridge is sensed in step S210. In step S220, whether the first gas concentration of the gas generated by the first filter cartridge is lower than a predetermined threshold is determined as a replacement condition. If it is determined that the concentration of the first gas is not lower than the predetermined threshold, the system continues to use the first filter cartridge to separate the first gas.

[0099] On the other hand, if it is determined in step S220 that the first gas concentration of the gas produced by the first filter cartridge is lower than the determined threshold, the system switches the gas flow through the gas fractionator to the second filter cartridge in step S230. In addition, at that time, or at any time before the second filter cartridge is exhausted, the first filter cartridge can be replaced or allowed to self-regenerate. Next, in step S240, the second filter cartridge is used to separate the first gas. In step S250, the first gas concentration in the gas produced by the second filter cartridge is sensed. In step S260, it is determined whether the first gas concentration of the gas produced by the second filter cartridge has dropped below a predetermined threshold. If not, the system continues to use the second filter cartridge to separate the first gas. On the other hand, if it is determined in step 260 that the first gas concentration is lower than the predetermined threshold, the system switches the flow to the first filter cartridge in step S270, which has been replaced or regenerated at this time and is a fresh filter cartridge. At this time or at a later time before the first filter cartridge has been exhausted, the operator replaces the second filter cartridge unless the system is a system in which the filter cartridge is allowed to self-regenerate.

[0100] It should be understood that steps S210 and S250, i.e., the first gas concentration sensing steps, can be performed substantially continuously by the first gas concentration sensor when any filter cartridge is being used, and steps S220 and S260 to determine whether the first gas concentration drops below a predetermined threshold can also be performed substantially continuously by the control system.

[0101] The present disclosure is made with the help of functional building blocks that illustrate the implementation of specified functions. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined in this article. As long as the specified functions are properly performed, different divisions of functions are possible.

[0102] The above description includes examples of one or more embodiments. Of course, it is not possible to describe every conceivable combination of components or methodology for the purpose of describing these embodiments, but it will be appreciated by those of ordinary skill in the art that many additional combinations and arrangements of various embodiments are possible. Therefore, the described embodiments are intended to cover all such changes, modifications and variations that fall within the spirit and scope of the appended claims. In addition, with respect to the term "comprising" used in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term "including" because "including" is interpreted when used as a transitional word in the claims. In addition, although the elements of the described aspects and / or embodiments may be described or claimed in the singular, the plural may be considered unless a limitation to the singular is explicitly stated. In addition, unless otherwise stated, all or a portion of any aspect and / or embodiment may be used together with all or a portion of any other aspect and / or embodiment.

[0103] The embodiments may be further described using the following aspects.

[0104] 1. A system for controlling the composition of a gas supplied to a portion of a lithographic apparatus, the system comprising:

[0105] an inlet adapted to be connected to a source of an initial gas, the initial gas comprising a first gas component and a second gas component;

[0106] a gas fractionator in fluid communication with the inlet and arranged to receive the initial gas and adapted to produce a separated gas having a concentrated first gas component; and

[0107] An outlet is in fluid communication with the gas fractionator and is arranged to receive a separation gas and is adapted to be connected in fluid communication with the portion of the lithographic apparatus to supply the separation gas to the portion of the lithographic apparatus.

[0108] 2. The system of aspect 1, wherein the first gas comprises oxygen.

[0109] 3. The system of aspect 1, wherein the first gas comprises nitrogen.

[0110] 4. The system of clause 1, wherein the portion of the lithographic apparatus comprises an extreme ultraviolet (EUV) light source.

[0111] 5. The system of clause 1, wherein the portion of the lithographic apparatus comprises a scanner.

[0112] 6. The system of aspect 1, wherein the initial gas comprises clean dry air (CDA).

[0113] 7. The system of aspect 1, wherein the initial gas comprises extra clean dry air (XCDA).

[0114] 8. The system of aspect 1, wherein the gas fractionator comprises at least one membrane filter.

[0115] 9. The system of aspect 1, wherein the gas fractionator comprises a multi-stage membrane filtration system comprising at least two membrane filters arranged in series.

[0116] 10. The system of aspect 1, wherein the gas fractionator comprises at least one molecular sieve.

[0117] 11. The system of aspect 1, wherein the initial gas has a second gas concentration greater than 75% by volume and the separation gas has a second gas concentration less than 5% by volume.

[0118] 12. The system of aspect 11, wherein the gas fractionator comprises a dual cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

[0119] 13. The system according to aspect 12, wherein the second molecular sieve is not used when the first molecular sieve is being used, and the system further comprises:

[0120] a replacement condition sensing module arranged to sense a replacement condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and

[0121] a controller responsively connected to the replacement condition sensing module and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition.

[0122] 14. The system according to aspect 13, wherein the replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of an initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

[0123] 15. A system according to aspect 13, wherein

[0124] The replacement condition sensing module includes a first gas concentration sensor arranged to sense a concentration of the first gas in the separated gas and generate a signal indicative of the concentration of the first gas in the separated gas; and

[0125] The system also includes a controller responsively connected to the first gas concentration sensor and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

[0126] 16. The system according to aspect 1 further includes a hydrogen delivery line arranged to deliver a hydrogen-containing gas to the portion of the lithographic device, and wherein the outlet is fluidly connected to the hydrogen delivery line to inject the separation gas into the hydrogen delivery line.

[0127] 17. A lithographic apparatus comprising an extreme ultraviolet (EUV) light source system, the lithographic apparatus comprising:

[0128] a chamber including a collector mirror;

[0129] a hydrogen delivery line arranged to deliver a hydrogen-containing gas into the chamber;

[0130] an inlet adapted to be connected to a source of an initial gas, the initial gas comprising a first gas component;

[0131] a gas fractionator in fluid communication with the inlet and arranged to receive the initial gas and adapted to at least partially separate the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; and

[0132] An outlet is in fluid communication with the gas fractionator and is arranged to receive the separated gas and is connected in fluid communication with the hydrogen delivery line to inject the separated gas into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

[0133] 18. The lithographic apparatus of clause 17, wherein the first gas component comprises oxygen.

[0134] 19. The lithographic apparatus of clause 17, wherein the first gas component comprises nitrogen.

[0135] 20. The lithographic apparatus of clause 17, wherein the gas fractionator comprises at least one membrane filter.

[0136] 21. The lithographic apparatus of clause 17, wherein the gas fractionator comprises a multi-stage membrane filtration system comprising at least two membrane filters arranged in series.

[0137] 22. The lithographic apparatus of clause 17, wherein the gas fractionator comprises at least one molecular sieve.

[0138] 23. The lithographic apparatus of clause 17, wherein the initial gas has a second gas concentration greater than 75% by volume, and the separation gas has a second gas concentration less than 5% by volume.

[0139] 24. The lithographic apparatus of clause 22, wherein the gas fractionator comprises a double cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

[0140] 25. The lithographic apparatus of aspect 24, wherein the second molecular sieve is not used when the first molecular sieve is being used, the system further comprising:

[0141] a replacement condition sensing module arranged to sense a replacement condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and

[0142] a controller responsively connected to the replacement condition sensing module and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition.

[0143] 26. The lithographic apparatus according to clause 25, wherein the replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of an initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

[0144] 27. The lithographic apparatus of clause 25, wherein

[0145] The replacement condition sensing module includes a first gas concentration sensor arranged to sense a concentration of the first gas in the separated gas and generate a signal indicative of the concentration of the first gas in the separated gas; and

[0146] The system also includes a controller responsively connected to the first gas concentration sensor and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

[0147] 28. A method of controlling the composition of a gas supplied to a portion of a lithographic apparatus, the method comprising:

[0148] supplying an initial gas, wherein the initial gas includes a first gas component;

[0149] at least partially separating the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; and

[0150] The separation gas is supplied to the portion of the lithographic apparatus.

[0151] 29. The method of aspect 28, wherein the first gas component comprises primarily oxygen.

[0152] 30. The method of aspect 28, wherein the first gas component consists primarily of nitrogen.

[0153] 31. The method of clause 28, wherein the portion of the lithographic apparatus comprises an extreme ultraviolet (EUV) light source portion.

[0154] 32. A method according to clause 28, wherein the portion of the lithographic apparatus comprises a scanner.

[0155] 33. The method of aspect 28, wherein supplying the initial gas comprises supplying clean dry air (CDA).

[0156] 34. The method of aspect 28, wherein supplying the initial gas comprises supplying extra clean dry air (XCDA).

[0157] 35. The method of aspect 28, wherein at least partially separating the first gas component to produce the separated gas is performed using at least one membrane filter.

[0158] 36. The method of aspect 28, wherein at least partially separating the first gas component to produce the separated gas is performed using a multi-stage membrane filtration system comprising at least two membrane filters arranged in series.

[0159] 37. The method of aspect 28, wherein at least partially separating the first gas to produce a separated gas is performed using at least one molecular sieve.

[0160] 38. The method of aspect 28, wherein the initial gas has a second gas concentration greater than 75% by volume and the separated gas has a second gas concentration less than 5% by volume.

[0161] 39. The method of aspect 28, wherein at least partially separating the first gas component to produce the separated gas is performed using a dual cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

[0162] 40. The method according to aspect 39, wherein the second molecular sieve is not used when the first molecular sieve is being used, the method further comprising:

[0163] sensing a change condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and

[0164] The initial gas is initially directed through the first molecular sieve for a first period of time, and switched to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

[0165] 41. The method according to aspect 40, wherein the replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of the initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

[0166] 42. A method according to aspect 40, wherein

[0167] Sensing the replacement condition includes sensing a first gas concentration of a first gas in the separation gas and generating a signal indicative of the concentration of the first gas in the separation gas; and

[0168] The initial gas is initially directed through the first molecular sieve for a first period of time, and switched to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

[0169] 43. The method of clause 28, wherein supplying the separation gas to the portion of the lithographic apparatus comprises injecting the separation gas into a hydrogen delivery line arranged to supply a hydrogen-containing gas to the portion of the lithographic apparatus.

[0170] 44. A method of controlling the composition of a gas supplied to an extreme ultraviolet (EUV) light source portion of a lithographic apparatus, the method comprising:

[0171] delivering a hydrogen-containing gas into a hydrogen delivery line, the hydrogen delivery line being arranged to deliver the hydrogen-containing gas into a chamber of the EUV light source, the chamber comprising a collector mirror;

[0172] supplying an initial gas, wherein the initial gas includes a first gas component;

[0173] at least partially separating the first gas component to produce a separated gas having a concentrated first gas component; and

[0174] A concentrated first gas component is injected into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

[0175] 45. The method of aspect 44, wherein at least partially separating the first gas component to produce the separated gas is performed using at least one membrane filter.

[0176] 46. ​​The method of aspect 44, wherein at least partially separating the first gas component to produce the separated gas is performed using a multi-stage membrane filtration system comprising at least two membrane filters arranged in series.

[0177] 47. The method of aspect 46, wherein at least partially separating the first gas component to produce the separated gas is performed using at least one molecular sieve.

[0178] 48. The method of aspect 44, wherein the initial gas has a second gas concentration greater than 75% by volume and the concentrated first gas component has a second gas concentration less than 5% by volume.

[0179] 49. The method of aspect 44, wherein at least partially separating the first gas component to produce the separated gas is performed using a dual cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

[0180] 50. The method according to aspect 44, further comprising:

[0181] directing the initial gas through the first molecular sieve;

[0182] sensing a concentration of a first gas in the separated gas and generating a signal indicative of the concentration of the first gas in the separated gas; and

[0183] Directing the initial gas through the first molecular sieve is stopped, and the initial gas is directed through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

[0184] 51. An apparatus for producing a separation gas, the apparatus comprising:

[0185] an initial gas input device arranged to receive an initial gas having a first oxygen concentration;

[0186] a gas separator in fluid communication with the initial gas input and having a first mesh filter member and a second mesh filter member, the gas separator being arranged to separate the separation gas from the initial gas, the separation gas having a second oxygen concentration greater than the first oxygen concentration;

[0187] an oxygen delivery line in fluid communication with the gas separator;

[0188] an oxygen sensor in fluid communication with the oxygen delivery line and arranged to sense the second oxygen concentration;

[0189] a controller capable of switching the gas separator between a first operating mode in which the gas separator uses the first mesh filter member without using the second mesh filter member to separate the separation gas from the initial gas and a second operating mode in which the gas separator uses the second mesh filter member without using the first mesh filter member to separate the separation gas from the initial gas; and

[0190] a gas control panel capable of adjusting the amount of oxygen from the oxygen delivery line to be delivered to a hydrogen delivery line arranged to deliver gas to a source of extreme ultraviolet radiation,

[0191] Wherein, the initial gas includes clean dry air (CDA) or ultra clean dry air (XCDA).

[0192] 52. The apparatus of aspect 51, wherein the first mesh filter member comprises a first molecular sieve filter, and wherein the second mesh filter member comprises a second molecular sieve filter.

[0193] 53. The apparatus of aspect 51, further comprising a flashback arrestor on the oxygen transfer line downstream of the gas separator.

[0194] 54. The apparatus of aspect 51, further comprising an oxygen sensor positioned in the oxygen delivery line downstream of the gas separator.

[0195] 55. The apparatus of aspect 51, further comprising a nitrogen transfer line adapted to transfer nitrogen from the gas separator.

[0196] 56. The apparatus of aspect 55, further comprising an exhaust line adapted to controllably exhaust the nitrogen transfer line and the oxygen transfer line.

[0197] 57. Apparatus according to aspect 56, wherein the controller or a further controller is adapted to open and close the exhaust line.

[0198] The implementations described above and other implementations are within the scope of the following claims.

Claims

1. A system for controlling the composition of a gas supplied to a portion of a lithographic apparatus, the system comprising: an inlet adapted to be connected to a source of an initial gas, the initial gas comprising a first gas component and a second gas component; a gas fractionator in fluid communication with the inlet and arranged to receive the initial gas and adapted to produce a separated gas having a concentrated first gas component; as well as An outlet is in fluid communication with the gas fractionator and is arranged to receive a separation gas and is adapted to be connected in fluid communication with the portion of the lithographic apparatus to supply the separation gas to the portion of the lithographic apparatus.

2. The system according to claim 1, wherein: The first gas includes oxygen.

3. The system according to claim 1, wherein: The first gas includes nitrogen.

4. The system according to claim 1, wherein: The portion of the lithographic apparatus comprises an extreme ultraviolet (EUV) light source.

5. The system according to claim 1, wherein: The portion of the lithographic apparatus comprises a scanner.

6. The system according to claim 1, wherein: The initial gas includes clean dry air (CDA).

7. The system according to claim 1, wherein: The initial gas includes ultra clean dry air (XCDA).

8. The system according to claim 1, wherein: The gas fractionator comprises at least one membrane filter.

9. The system according to claim 1, wherein: The gas fractionator includes a multi-stage membrane filtration system including at least two membrane filters arranged in series.

10. The system according to claim 1, wherein: The gas fractionator includes at least one molecular sieve.

11. The system according to claim 1, wherein: The initial gas has a second gas concentration greater than 75% by volume, and the separated gas has a second gas concentration less than 5% by volume.

12. The system according to claim 11, wherein: The gas fractionator comprises a double cartridge molecular sieve, and the double cartridge molecular sieve comprises a first molecular sieve and a second molecular sieve.

13. The system according to claim 12, wherein: When the first molecular sieve is being used, the second molecular sieve is not used, and the system further comprises: a replacement condition sensing module arranged to sense a replacement condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and a controller responsively connected to the replacement condition sensing module and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition.

14. The system according to claim 13, wherein: The replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of the initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

15. The system of claim 13, wherein The replacement condition sensing module includes a first gas concentration sensor arranged to sense a concentration of the first gas in the separated gas and generate a signal indicative of the concentration of the first gas in the separated gas; and The system also includes a controller responsively connected to the first gas concentration sensor and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

16. The system of claim 1, further comprising a hydrogen delivery line arranged to deliver a hydrogen-containing gas into the portion of the lithographic apparatus, and wherein The outlet is in fluid communication with the hydrogen delivery line to inject the separated gas into the hydrogen delivery line.

17. A lithographic apparatus comprising an extreme ultraviolet (EUV) light source system, the lithographic apparatus comprising: a chamber including a collector mirror; a hydrogen delivery line arranged to deliver a hydrogen-containing gas into the chamber; an inlet adapted to be connected to a source of an initial gas, the initial gas comprising a first gas component; a gas fractionator in fluid communication with the inlet and arranged to receive the initial gas, and adapted to at least partially separate the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; as well as An outlet is in fluid communication with the gas fractionator and is arranged to receive the separated gas and is connected in fluid communication with the hydrogen delivery line to inject the separated gas into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

18. The lithographic apparatus of claim 17, wherein: The first gas component includes oxygen.

19. The lithographic apparatus of claim 17, wherein: The first gas component includes nitrogen.

20. The lithographic apparatus of claim 17, wherein: The gas fractionator comprises at least one membrane filter.

21. The lithographic apparatus of claim 17, wherein: The gas fractionator includes a multi-stage membrane filtration system including at least two membrane filters arranged in series.

22. The lithographic apparatus of claim 17, wherein: The gas fractionator includes at least one molecular sieve.

23. The lithographic apparatus of claim 17, wherein: The initial gas has a second gas concentration greater than 75% by volume, and the separated gas has a second gas concentration less than 5% by volume.

24. The lithographic apparatus of claim 22, wherein: The gas fractionator comprises a double cartridge molecular sieve, and the double cartridge molecular sieve comprises a first molecular sieve and a second molecular sieve.

25. The lithographic apparatus of claim 24, wherein: When the first molecular sieve is being used, the second molecular sieve is not used, and the system further comprises: a replacement condition sensing module arranged to sense a replacement condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and a controller responsively connected to the replacement condition sensing module and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on sensing the replacement condition.

26. The lithographic apparatus of claim 25, wherein: The replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of the initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

27. The lithographic apparatus of claim 25, wherein The replacement condition sensing module includes a first gas concentration sensor arranged to sense a concentration of the first gas in the separated gas and generate a signal indicative of the concentration of the first gas in the separated gas; and The system also includes a controller responsively connected to the first gas concentration sensor and adapted to initially direct the initial gas through the first molecular sieve for a first time period and to switch to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

28. A method of controlling the composition of a gas supplied to a portion of a lithographic apparatus, the method comprising: supplying an initial gas, wherein the initial gas includes a first gas component; at least partially separating the first gas component from the initial gas to produce a separated gas having a concentrated first gas component; and The separation gas is supplied to the portion of the lithographic apparatus.

29. The method according to claim 28, wherein: The first gas component mainly includes oxygen.

30. The method of claim 28, wherein: The first gas component mainly includes nitrogen.

31. The method of claim 28, wherein: The portion of the lithographic apparatus includes an extreme ultraviolet (EUV) light source portion.

32. The method of claim 28, wherein: The portion of the lithographic apparatus comprises a scanner.

33. The method of claim 28, wherein: Supplying the initial gas includes supplying clean dry air (CDA).

34. The method of claim 28, wherein: Supplying the initial gas includes supplying ultra clean dry air (XCDA).

35. The method of claim 28, wherein: At least partially separating the first gas component to produce the separated gas is performed using at least one membrane filter.

36. The method of claim 28, wherein: At least partially separating the first gas component to produce the separated gas is performed using a multi-stage membrane filtration system including at least two membrane filters arranged in series.

37. The method of claim 28, wherein: At least partially separating the first gas to produce a separated gas is performed using at least one molecular sieve.

38. The method of claim 28, wherein: The initial gas has a second gas concentration greater than 75% by volume, and the separated gas has a second gas concentration less than 5% by volume.

39. The method of claim 28, wherein: At least partially separating the first gas component to produce the separated gas is performed using a dual cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

40. The method of claim 39, wherein: When the first molecular sieve is being used, the second molecular sieve is not used, and the method further comprises: sensing a change condition in which the system switches from using the first filter cartridge to using the second filter cartridge; and The initial gas is initially directed through the first molecular sieve for a first time period, and switching to directing the initial gas through the second molecular sieve is based at least in part on sensing the replacement condition.

41. The method of claim 40, wherein: The replacement condition is at least one of a concentration of the first gas in the separation gas, a volume of the initial gas processed by the first filter cartridge, and an operation time of the first filter cartridge.

42. The method of claim 40, wherein Sensing the replacement condition includes sensing a first gas concentration of a first gas in the separation gas and generating a signal indicative of the concentration of the first gas in the separation gas; and The initial gas is initially directed through the first molecular sieve for a first period of time, and switched to directing the initial gas through the second molecular sieve based at least in part on a concentration of the first gas in the separated gas.

43. The method of claim 28, wherein: Supplying the separation gas to the portion of the lithographic apparatus comprises injecting the separation gas into a hydrogen delivery line arranged to deliver a hydrogen-containing gas into the portion of the lithographic apparatus.

44. A method of controlling the composition of a gas supplied to an extreme ultraviolet (EUV) light source portion of a lithographic apparatus, the method comprising: delivering a hydrogen-containing gas into a hydrogen delivery line, the hydrogen delivery line being arranged to deliver the hydrogen-containing gas into a chamber of the EUV light source, the chamber comprising a collector mirror; supplying an initial gas, wherein the initial gas includes a first gas component; at least partially separating the first gas component to produce a separated gas having a concentrated first gas component; as well as A concentrated first gas component is injected into the hydrogen delivery line to supply the concentrated first gas component to the chamber.

45. The method of claim 44, wherein: At least partially separating the first gas component to produce the separated gas is performed using at least one membrane filter.

46. ​​The method of claim 44, wherein: At least partially separating the first gas component to produce the separated gas is performed using a multi-stage membrane filtration system including at least two membrane filters arranged in series.

47. The method of claim 46, wherein: At least partially separating the first gas component to produce the separated gas is performed using at least one molecular sieve.

48. The method of claim 44, wherein: The initial gas has a second gas concentration greater than 75% by volume, and the concentrated first gas component has a second gas concentration less than 5% by volume.

49. The method of claim 44, wherein: At least partially separating the first gas component to produce the separated gas is performed using a dual cartridge molecular sieve comprising a first molecular sieve and a second molecular sieve.

50. The method of claim 44, further comprising: directing the initial gas through the first molecular sieve; sensing a concentration of a first gas in the separated gas and generating a signal indicative of the concentration of the first gas in the separated gas; as well as Directing the initial gas through the first molecular sieve is stopped, and the initial gas is directed through the second molecular sieve based at least in part on the concentration of the first gas in the separated gas.

51. An apparatus for producing a separation gas, the apparatus comprising: an initial gas input device arranged to receive an initial gas having a first oxygen concentration; a gas separator in fluid communication with the initial gas input and having a first mesh filter member and a second mesh filter member, the gas separator being arranged to separate the separation gas from the initial gas, the separation gas having a second oxygen concentration greater than the first oxygen concentration; an oxygen delivery line in fluid communication with the gas separator; an oxygen sensor in fluid communication with the oxygen delivery line and arranged to sense the second oxygen concentration; a controller capable of switching the gas separator between a first operating mode in which the gas separator uses the first mesh filter member without using the second mesh filter member to separate the separation gas from the initial gas and a second operating mode in which the gas separator uses the second mesh filter member without using the first mesh filter member to separate the separation gas from the initial gas; as well as a gas control panel capable of adjusting the amount of oxygen from the oxygen delivery line to be delivered to a hydrogen delivery line arranged to deliver gas to a source of extreme ultraviolet radiation, Wherein, the initial gas includes clean dry air (CDA) or ultra clean dry air (XCDA).

52. The apparatus of claim 51, wherein: The first mesh filter component comprises a first molecular sieve filter, and wherein the second mesh filter component comprises a second molecular sieve filter.

53. The apparatus of claim 51 further comprising a flashback arrestor on the oxygen delivery line downstream of the gas separator.

54. The apparatus of claim 51 further comprising an oxygen sensor positioned in the oxygen delivery line downstream of the gas separator.

55. The apparatus of claim 51, further comprising a nitrogen transfer line adapted to transfer nitrogen from the gas separator.

56. The apparatus of claim 55, further comprising an exhaust line adapted to controllably exhaust the nitrogen delivery line and the oxygen delivery line.

57. The apparatus of claim 56, wherein: The controller or a further controller is adapted to open and close the exhaust line.

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