Semiconductor processing system and operationg method thereof

Abstract

A method is provided. The method includes: generating first light from plasma of a semiconductor processing tool light source, the first light including in-band light within the extreme ultraviolet spectrum and out-of-band light outside the extreme ultraviolet spectrum; removing the out-of-band light from the first light by means of a filter assembly in direct contact with the tube to generate filtered light including the in-band light, the filter assembly having a filter element including a zirconium substrate and a transition metal substrate on the zirconium substrate; determining whether the filter assembly is degraded; performing maintenance operations on the filter assembly in response to filter assembly degrade; and performing a semiconductor process on a semiconductor wafer by the semiconductor processing tool in response to the filter assembly not being degraded.

Description

Technical Field

[0001] This disclosure relates to a semiconductor processing system and its operation method. Prior Technology

[0002] Semiconductor devices are formed on, in, and / or made from semiconductor wafers and are used in a variety of electronic devices, such as mobile phones, laptops, desktop computers, tablets, watches, gaming systems, and various other industrial, commercial, and consumer electronics. One or more semiconductor manufacturing processes are performed to form semiconductor devices on, in, and / or on semiconductor wafers. Summary of the Invention

[0003] According to some embodiments of this disclosure, a method is provided. This method includes: generating first light from plasma of a light source of a semiconductor processing tool, the first light comprising in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum; generating filtered light comprising in-band light by removing the out-of-band light from the first light using a filter assembly having a filter element, wherein the filter element comprises a zirconium substrate and a transition metal substrate on the zirconium substrate, and the filter assembly is positioned between the plasma and a collecting mirror; receiving a first portion of the first light by a first sensor before generating the filtered light; receiving a second portion of the filtered light by a second sensor after generating the filtered light; generating a first brightness value associated with the first portion; generating a second brightness value associated with the second portion; determining a brightness difference based on the first brightness value and the second brightness value; determining whether the brightness difference exceeds a threshold; performing a semiconductor process on a semiconductor wafer by the semiconductor processing tool in response that the brightness difference does not exceed the threshold; and performing a maintenance operation on the filter assembly in response that the brightness difference exceeds the threshold.

[0004] According to some embodiments of this disclosure, a method is provided. This method includes: generating first light from plasma of a light source of a semiconductor processing tool, the first light including in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum; generating filtered light including in-band light by removing the out-of-band light from the first light via a filter assembly of a direct contact tube, the filter assembly having a filter element including a zirconium substrate and a transition metal substrate on the zirconium substrate; determining whether the filter assembly has been degraded; performing maintenance operations on the filter assembly in response to degraded filter assembly; and performing a semiconductor process on a semiconductor wafer by the semiconductor processing tool in response to no degraded filter assembly.

[0005] According to some embodiments of this disclosure, a system is provided. The system includes: a light source operable to generate plasma emitting a first light, the first light comprising in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum; a collecting mirror; a wafer stage, the optical path defined as a first chamber of the light source leading to the collecting mirror and then to the wafer stage; a dome stage positioned along the optical path between the collecting mirror and the wafer stage; and a filter assembly positioned on the optical path, the filter assembly comprising a filter element having a first zirconium substrate and a top cover layer. Simple Explanation of the Diagram

[0006] When reading in conjunction with the diagrams, the various aspects of this disclosure are best understood from the following detailed description. It should be noted that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, for clarity of explanation, the dimensions of the various features may be arbitrarily increased or decreased.

[0007] Figure 1A illustrates a schematic diagram of the system according to some embodiments.

[0008] Figure 1B illustrates a schematic diagram of the system according to some embodiments.

[0009] Figure 1C illustrates a schematic diagram of the light source in the system of Figure 1B according to some embodiments.

[0010] Figure 1D illustrates the optical path in the system of Figures 1A-1C according to some embodiments.

[0011] Figure 2A illustrates a schematic diagram of a filter assembly according to some embodiments.

[0012] Figure 2B illustrates a schematic diagram of a filter element according to some embodiments.

[0013] Figure 2C illustrates a schematic diagram of a filter element according to some embodiments.

[0014] Figure 2D illustrates a schematic diagram of a filter element according to some embodiments.

[0015] Figure 3A illustrates a schematic side cross-sectional view of a filter element according to some embodiments.

[0016] Figure 3B illustrates a schematic side cross-sectional view of a filter element according to some embodiments.

[0017] Figure 4A illustrates a schematic diagram of a filter component degradation detection system according to some embodiments.

[0018] Figure 4B illustrates a schematic diagram of a filter component degradation detection system according to some embodiments.

[0019] Figure 4C illustrates a schematic diagram of a filter component degradation detection system according to some embodiments.

[0020] Figure 5 illustrates a schematic diagram of a filter component monitoring system according to some embodiments.

[0021] Figure 6 illustrates a flowchart of a method according to some embodiments.

[0022] Figure 7 illustrates a flowchart of a method according to some embodiments.

[0023] Figure 8 illustrates an illustrative computer-readable medium according to some embodiments, which may contain computer instructions configured to embody one or more of the specifications described herein that are executable by a processor. Implementation

[0024] The following disclosure provides several different embodiments or instances for implementing various features of the provided subject matter. Specific examples of elements and arrangements are described below to simplify this disclosure. Of course, these elements and arrangements are merely examples and are not intended to be limiting. For example, in the following description, the formation of a first feature on or over a second feature may include embodiments where the first and second features are formed in direct contact, and may further include embodiments where additional features may be formed between the first and second features such that the first and second features are not in direct contact. Additionally, this disclosure may repeat schematic designations and / or letters in various instances. Such repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0025] Furthermore, for ease of description, spatially related terms such as "below," "under," "lower part," "above," "above," and "upper part" may be used herein to describe the relationship between one element or feature and another element or feature as shown in the figures. In addition to the orientations depicted in the figures, spatially related terms are intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein shall be interpreted accordingly.

[0026] The terms "overlying" and / or similar terms can be used to describe an element or feature that overlaps with another element or feature in the vertical direction and is located at a higher height than the other element or feature. For example, if a first element is located at a higher height than a second element, and at least a portion of the first element overlaps with at least a portion of the second element in the vertical direction, then the first element overlies the second element.

[0027] The term "underlying" and / or similar terms can be used to describe an element or feature that overlaps vertically with another element or feature and is at a lower height than the other element or feature. For example, if a first element is at a lower height than a second element, and at least a portion of the first element overlaps vertically with at least a portion of the second element, then the first element is underlying the second element.

[0028] The term "above" can be used to describe a component or feature that is at a higher height than another component or feature. For example, if the first component is at a higher height than the second component, then the first component is above the second component.

[0029] The term "below" can be used to describe an element or feature that is at a lower height than another element or feature. For example, if the first element is at a lower height than the second element, then the first element is below the second element.

[0030] With advancements in advanced semiconductor process nodes, optical inspection has been implemented in mass production. Optical inspection relies on extreme ultraviolet (EUV) emission and includes subsequent algorithmic calculations. Therefore, extending the lifetime of components in optical inspection systems is beneficial. Optical inspection systems may include zirconium filters capable of removing light outside the EUV spectrum (approximately 13.5 nanometers or "nm") to maintain high-quality EUV light. The use of zirconium filters in optical inspection systems can lead to various bottlenecks, one of which is brightness degradation, which may be caused by oxidation of the zirconium filter. Zirconium filters may also be vulnerable to tin debris attack, where high-momentum tin debris can penetrate the filter, causing holes. Once a hole forms in the zirconium filter, unwanted heat from out-of-band (OOB) spectral light (primarily in the 100nm to 800nm ​​and >1000nm range) can degrade subsequent mirrors, potentially causing mirror damage.

[0031] In the embodiments disclosed herein, the filtering element of the zirconium filter includes a zirconium-based layer and a top cover layer to prevent degradation of the zirconium-based layer. Degradation may be the result of oxidation, porosity, or both. In some embodiments, the filtering element further includes a transition metal substrate located between the top cover layer and the zirconium-based layer, which can facilitate the reflection of out-of-band (OOB) spectrum light before it reaches the zirconium-based layer. In some embodiments, one or more surfaces of the filtering element are surface-treated to be hydrophobic. In the filtering element, substantially only in-band extreme ultraviolet (EUV) spectrum light is transmitted, while out-of-band (OOB) spectrum light is reflected, absorbed, or both. The filtering element is beneficial for preventing oxidation, enhancing its strength, and extending tooling operating time.

[0032] The embodiments disclosed herein further provide detection of filter element degradation. In some embodiments, the brightness of extreme ultraviolet light entering and leaving the filter element is detected to determine whether the filter element has degraded. In some embodiments, the pressure difference between each side of the filter element is measured to determine whether the filter element has degraded. For example, a hole penetrating the filter element may result in a very low pressure difference, which may indicate filter element degradation. In some embodiments, the focal length of one or more mirrors in the system is measured over time, and the displacement of the focal length is used to determine whether the filter element has degraded. Therefore, timely detection of filter element degradation provides a reliable process flow for systems including filter elements.

[0033] Figure 1A illustrates a schematic diagram of system 10 according to some embodiments. In some embodiments, system 10 is a lithography system, such as a lithography exposure system, and may be referred to as lithography system 10 or lithography exposure system 10. In some embodiments, system 10 is a semiconductor processing tool and may be referred to as semiconductor processing tool 10.

[0034] In some embodiments, system 10 is an extreme ultraviolet (EUV) lithography system designed to expose a photoresist layer by EUV radiation. According to some embodiments, system 10 includes a light source 120, an illuminator 140, a stage 16, a projection optics module (or projection optics box, POB) 130, and a substrate stage. In some embodiments, system 10 includes an image sensor 26 that can be positioned at the location where the substrate stage would normally be. That is, system 10 may include the image sensor 26 in a first operation (e.g., a measurement operation) and may include the substrate stage in a second operation (e.g., a lithography exposure operation). Components of system 10 may be added or omitted, and this disclosure should not be limited to these embodiments. Some components of system 10 may be rearranged in other embodiments. For example, the position of the collector mirror 60 relative to the illumination point 52 and the illuminator 140 may differ from that depicted in FIG. 1A. FIG. 1B and FIG. 1C depict and describe embodiments including a collector mirror 60A with a different arrangement than the collector mirror 60. Collecting mirrors 60 and 60A can each be referred to as collecting mirrors.

[0035] In some embodiments, the light source 120 is configured to produce light radiation 84 (or "first light 84") with wavelengths between about 1 nanometer and about 100 nanometers. In a particular example, the light source 120 produces EUV radiation 84 with wavelengths concentrated at about or substantially about 13.5 nanometers. Therefore, the light source 120 is also referred to as an EUV radiation source. However, it should be understood that the light source 120 is not limited to emitting EUV radiation 84. The light source 120 can be used to perform any high-intensity photon emission from excited target fuel.

[0036] The light source 120 includes a first chamber 122 and a second chamber 124, which are optically connected to each other via a transport line 14. The first chamber 122 can operate under a first pressure, while the second chamber 124 can operate under a second pressure different from the first pressure.

[0037] In some embodiments, the light source 120 includes a droplet generator that delivers a target fuel to an excitation region where at least one laser pulse from the laser generator strikes the droplet. In one embodiment, the target fuel comprises tin (Sn). The laser generator is configured to generate at least one laser pulse to allow the droplet to be converted into plasma 88. In some embodiments, the laser generator is configured to generate laser pulses to an illumination point 52 to convert the droplet into plasma 88 that generates EUV radiation 84. The laser pulses can be guided through a window (or lens) and irradiate the droplet at the illumination point 52. In some embodiments, the illumination point 52 is located in a first chamber 122.

[0038] Plasma 88 emits EUV radiation 84, which is collected by a collecting mirror 60 and directed toward an illuminator 140. The collecting mirror 60 reflects and focuses the EUV radiation 84 for lithography processes performed by an exposure tool (such as system 10). In some embodiments, the collecting mirror 60 is located in a second chamber 124.

[0039] In some embodiments, the laser generator is a carbon dioxide (CO2) laser source. In some embodiments, the laser generator is used to generate a single-wavelength laser pulse. The laser pulse can be transmitted via optical components to focus and determine the incident angle of the laser pulse. In some embodiments, the spot size of the laser pulse is approximately 200-300 micrometers, for example, 225 micrometers. The laser pulse is generated with a specific drive power to meet wafer production targets, such as a capacity of 125 wafers per hour (WPH), although higher WPHs may be achieved. In some embodiments, the laser pulse is equipped with approximately 23 kilowatts of drive power. In various embodiments, the drive power of the laser pulse is at least 20 kilowatts, for example, 27 kilowatts.

[0040] In various embodiments, the illuminator 140 includes various refractive optical elements, such as a single lens or a lens system having multiple mirrors 100, such as lenses (zone plates) or alternatively, reflective optical elements (for EUV lithography systems), such as a single mirror or a mirror system having multiple mirrors, to direct light from the light source 120 onto the stage 16, and particularly onto the screen 18 fixed to the stage 16. In this embodiment where the light source 120 produces light in the EUV wavelength range, reflective optical elements are used. In some embodiments, the illuminator 140 includes at least three lenses.

[0041] A stage 16 is configured to hold the mask 18. In some embodiments, the stage 16 includes an electrostatic chuck to hold the mask 18. This is because gas molecules absorb EUV radiation and the lithography exposure system used for EUV lithography patterning is maintained in a vacuum environment to avoid EUV intensity loss. In this disclosure, the terms mask, photomask, and photomask are used interchangeably. In this embodiment, the mask 18 is a reflective mask. One exemplary structure of the mask 18 includes a substrate having a suitable material such as a low thermal expansion material (LTEM) or fused silica. In various examples, the LTEM includes TiO2-doped SiO2, or other suitable materials having low thermal expansion. The mask 18 includes a reflective multilayer deposited on the substrate.

[0042] A projection optics module (or projection optics box (POB)) 130 is configured to image the pattern of the mask 18 onto a semiconductor wafer fixed to a substrate stage of the system 10. In some embodiments, the POB 130 has refractive optics (e.g., for a UV lithography system) or alternatively reflective optics (e.g., for an EUV lithography system), such as optics 110. Light directed from the mask 18 (carrying an image of the pattern defined on the mask) is collected by the POB 130. Illuminator 140 and POB 130 are collectively referred to as the optical module of the system 10. In some embodiments, the POB 130 includes at least five reflective optics.

[0043] In some embodiments, the semiconductor wafer is made of silicon or other semiconductor materials. Alternatively or additionally, the semiconductor wafer may include other elemental semiconductor materials, such as germanium (Ge). In some embodiments, the semiconductor wafer is made of compound semiconductors, such as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), or indium phosphide (InP). In some embodiments, the semiconductor wafer is made of alloy semiconductors, such as silicon germanium (SiGe), silicon germanium carbide (SiGeC), gallium arsenide phosphide (GaAsP), or gallium indium phosphide (GaInP). In some other embodiments, the semiconductor wafer may be a silicon-on-insulator (SOI) or germanium-on-insulator (GOI) substrate.

[0044] In some embodiments, system 10 is operable to perform one or more semiconductor manufacturing process operations on a semiconductor wafer. A semiconductor wafer (or simply "wafer") includes at least one substrate, a photomask, a semiconductor device, a dielectric layer, an epitaxial layer, a silicon-on-insulator (SOI) structure, a semiconductor layer, a conductive material layer, a die, etc. The semiconductor wafer includes at least one silicon, germanium, carbide, arsenide, gallium, arsenic, phosphide, indium, antimonide, silicon germanium (SiGe), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), indium gallium phosphide (InGaP), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), gallium arsenide phosphide (GaAsP), aluminum indium arsenide (AlInAs), aluminum gallium arsenide (AlGaAs), gallium indium arsenide (GaInAs), gallium indium phosphide (GaInP), gallium indium arsenide phosphide (GaInAsP), or other suitable materials. The semiconductor wafer includes at least one single-crystal silicon, having... <100> Crystalline-oriented silicon, possessing <110> Crystalline-oriented silicon, possessing <111> Crystallographically oriented silicon or other suitable materials. Other structures and / or configurations of semiconductor wafers are within the scope of this disclosure.

[0045] Semiconductor wafers can have a variety of device elements. Examples of device elements formed in a semiconductor wafer include transistors (e.g., metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), high voltage transistors, high frequency transistors, p-channel and / or n-channel field-effect transistors (PFETs / NFETs), etc.), diodes, and / or other suitable components. Various processes are performed to form the device elements, such as deposition, etching, implantation, lithography, annealing, and / or other suitable processes. In some embodiments, the semiconductor wafer is coated with a resist layer sensitive to extreme ultraviolet radiation. Various components, including those described above, are integrated together and operable to perform lithography processes.

[0046] System 10 may include other modules or be integrated (or coupled) with other modules, such as a cleaning module designed to supply hydrogen to light source 120. Hydrogen helps reduce contamination in light source 120.

[0047] System 10 includes a filter assembly 12. The filter assembly 12 is positioned within a second chamber 124. In operation, when light radiation 84, including in-band light (e.g., extreme ultraviolet light) and out-of-band light, is incident on the filter assembly 12, the filter assembly 12 can remove out-of-band light while allowing in-band light (e.g., extreme ultraviolet light) to pass through. Removing out-of-band light is beneficial because heat from out-of-band light (which may exist in the range of 100 nm to 800 nm and >1000 nm) can degrade the performance of subsequent mirrors, such as the collection mirror 60. Over time, the filter element of the filter assembly 12 may degrade, for example, due to oxidation or the formation of penetration holes. Oxidation can lead to a reduction in in-band light brightness. Holes in the filter element can allow out-of-band light to pass through to subsequent mirrors, which may cause the mirrors to heat up and damage them. For example, heating can increase the formation of oxides, hydrocarbons, or both on the surfaces of affected mirrors, such as the collection mirror 60. The addition of an oxide or hydrocarbon film on the reflectors 100, 110 of the collecting mirror 60, illuminator 140, or projection optics box 130 can reduce the brightness of the light within the band, thereby reducing the power output of the system 10.

[0048] In some embodiments, a filter assembly monitoring system or a portion thereof is located in a second chamber 124. The filter assembly monitoring system may include a first sensor 74 and a second sensor 76. The filter assembly monitoring system is operable to determine whether the filter element of the filter assembly 12 has been degraded.

[0049] In operation, out-of-band light is removed from the first light 84 by a filter assembly 12 located between the plasma 88 and the collecting mirror 60, generating filtered light 84F including in-band light. Before generating filtered light 84F, a first sensor 74 receives a first portion 841 of the first light 84. After generating filtered light 84F, a second sensor 76 receives a second portion 843 of filtered light 84F. As shown in FIG1A, the first sensor 74 can be positioned to receive the first portion 841 (which is part of the first light 84) incident on the filter assembly 12, and the second sensor 76 can be positioned to receive the second portion 843 reflected from the collecting mirror 60. In some embodiments, the second sensor 761 is positioned to receive the second portion 845 (which is part of filtered light 84F) incident on the collecting mirror 60 but not reflected by the collecting mirror 60. The second sensor 761 is indicated by dashed lines in FIG1A. In some embodiments, the first and second sensors 74, 76 are positioned on different (e.g., opposite) walls of the second chamber 124. In some embodiments, the first and second sensors 74 and 761 are positioned on the same wall of the second chamber 124.

[0050] In some embodiments, in addition to or instead of obtaining a second portion 843 or a second portion 845, the image sensor 26 receives output light 847 from the projection optics box 130. Output light 847 may also be referred to as the "second portion".

[0051] In operation, the first sensor 74 is operable to generate a first luminance value associated with the first portion 841, and the second sensor 76, the second sensor 761, or the image sensor 26 is operable to generate a second luminance value associated with the second portion 843, the second portion 845, or the output light 847, respectively. A luminance difference can then be determined based on the first and second luminance values. For example, the luminance difference can be determined by subtracting the second luminance value from the first luminance value. The filtered light 84F substantially excludes out-of-band light. When the first sensor 74 is sensitive to both out-of-band and in-band light, for example, the first luminance measured by the first sensor 74 may have a portion associated with out-of-band light. When calculating the luminance difference, the portion associated with out-of-band light can be removed by software. In some embodiments, the first sensor 74 is sensitive to in-band light but attenuated or completely insensitive to out-of-band light. In these embodiments, the portion associated with out-of-band light can be removed by the first sensor 74 rather than by software.

[0052] Based on the brightness difference, it can be determined whether the filter element of the filter assembly 12 has been degraded. For example, it can be determined whether the brightness difference exceeds a threshold. In response to the brightness difference not exceeding the threshold, it can be determined that the filter element has not been degraded, and the system 10 can perform semiconductor processing (e.g., lithography) on the semiconductor wafer. In response to the brightness difference exceeding the threshold, it can be determined that the filter element has been degraded, and maintenance operations can be performed on the filter assembly, such as removing, replacing, or repairing the filter element.

[0053] Figure 1B shows a schematic diagram of system 10A according to some embodiments. Figure 1C shows a schematic diagram of light source 120A of system 10A in Figure 1B according to some embodiments. In some embodiments, system 10A is a lithography system, such as a lithography exposure system, and may be referred to as lithography system 10A or lithography exposure system 10A. In some embodiments, system 10A is a semiconductor processing tool and may be referred to as semiconductor processing tool 10A.

[0054] Figure 1B shows a schematic and illustrated view of a lithography system 10A according to some embodiments. In some embodiments, the lithography system 10A is an extreme ultraviolet (EUV) lithography system designed for exposing photoresist layers by EUV radiation, and may also be referred to as an EUV system 10A. According to some embodiments, the lithography system 10A includes a light source 120A, an illuminator 140A, a stage 16A, a projection optics module (or projection optics box (POB)) 130A, and a wafer stage 24A. Components of the lithography system 10A may be added or omitted, and this disclosure should not be limited to the embodiments.

[0055] In some embodiments, light source 120A is configured to generate optical radiation 84A with wavelengths ranging from about 1 nanometer to about 100 nanometers. In a particular example, light source 120A generates EUV radiation 84A with a center wavelength of about 13.5 nanometers. Therefore, light source 120A is also referred to as an EUV radiation source. However, it should be understood that light source 120A is not limited to emitting EUV radiation 84. Light source 120A can be used to perform any high-intensity photon emission from self-stimulated target fuel.

[0056] In various embodiments, the illuminator 140A includes various refractive optical components, such as a single lens or a lens system with multiple mirrors 100A, e.g., lenses (zone plates) or alternatively, reflective optics (for EUV lithography systems), such as a single mirror or a mirror system with multiple mirrors, to guide light from the light source 120A to the stage 16A, particularly to the mask 18A fixed to the stage 16A. In this embodiment where the light source 120A produces light in the EUV wavelength range, reflective optics are used. In some embodiments, the illuminator 140 includes at least two lenses.

[0057] A stage 16A is configured to hold a mask 18A. In some embodiments, the stage 16A includes an electrostatic chuck to hold the mask 18A. This is because gas molecules absorb EUV radiation and the lithography exposure system used for EUV lithography patterning is maintained in a vacuum environment to avoid EUV intensity loss. In this disclosure, the terms mask, photomask, and photomask are used interchangeably. In this embodiment, the mask 18A is a reflective mask. An exemplary structure of the mask 18A includes a substrate having a suitable material such as a low thermal expansion material (LTEM) or fused silica. In various examples, the LTEM includes TiO2-doped SiO2, or other suitable materials having low thermal expansion. The mask 18A includes a reflective multilayer deposited on the substrate.

[0058] A projection optics module (or projection optics box (POB)) 130A is configured to image a pattern from a mask 18A onto a semiconductor wafer 22A fixed on a wafer stage 24A of a lithography system 10A. In some embodiments, the POB 130A has refractive optics (such as for a UV lithography system) or, alternatively, reflective optics (such as for an EUV lithography system), such as optics 110A. Light directed from the mask 18A carries an image of the pattern defined on the mask and is collected by the POB 130A. Illuminators 140A and the POB 130A are collectively referred to as the optical modules of the lithography system 10A. In some embodiments, the POB 130A includes at least five reflective optics.

[0059] In some embodiments, semiconductor wafer 22A is made of silicon or other semiconductor materials. Alternatively or additionally, semiconductor wafer 22A may include other basic semiconductor materials such as germanium (Ge). In some embodiments, semiconductor wafer 22A is made of materials such as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), or indium phosphide (InP). In some embodiments, semiconductor wafer is made of alloy semiconductors, such as silicon germanium (SiGe), silicon germanium carbide (SiGeC), gallium arsenide phosphide (GaAsP), or gallium indium phosphide (GaInP). In some other embodiments, semiconductor wafer may be a silicon-on-insulator (SOI) or germanium-on-insulator (GOI) substrate.

[0060] In some embodiments, system 10A is operable to perform one or more semiconductor manufacturing process operations on semiconductor wafer 22A. Semiconductor wafer 22A (or simply "wafer 22A") includes at least one substrate, photomask, semiconductor device, dielectric layer, epitaxial layer, silicon-on-insulator (SOI) structure, semiconductor layer, conductive material layer, die, etc. Semiconductor wafer 22A includes at least one silicon, germanium, carbide, arsenide, gallium, arsenic, phosphide, indium, antimonide, silicon germanium (SiGe), silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), indium gallium phosphide (InGaP), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb), gallium arsenide phosphide (GaAsP), aluminum indium arsenide (AlInAs), aluminum gallium arsenide (AlGaAs), gallium indium arsenide (GaInAs), gallium indium phosphide (GaInP), gallium indium arsenide (GaInAsP), or other suitable materials. Semiconductor wafer 22A includes at least one single-crystal silicon, having <100> Crystalline-oriented silicon, possessing <110> Crystalline-oriented silicon, possessing <111> Crystallographically oriented crystalline silicon or other suitable materials. Other structures and / or configurations of semiconductor wafers are within the scope of this disclosure.

[0061] Semiconductor wafer 22A may have various device elements. Examples of device elements formed in semiconductor wafer 22A include transistors (e.g., metal oxide semiconductor field effect transistors (MOSFETs), complementary metal oxide semiconductor (CMOS) transistors, bipolar junction transistors (BJTs), high voltage transistors, high frequency transistors, p-channel and / or n-channel field-effect transistors (PFETs / NFETs), etc.), diodes, and / or other suitable elements. Various processes are performed to form the device elements, such as deposition, etching, implantation, photolithography, annealing, and / or other suitable processes. In some embodiments, semiconductor wafer 22A is coated with an extreme ultraviolet light-sensitive resist layer. Various components including those elements described above are integrated together and operable to perform photolithography processes.

[0062] System 10A includes a filter assembly 12A. The filter assembly 12A is positioned between plasma 88A and focal point 87A. In some embodiments, as depicted by dashed lines in FIG1B, focal point 87A is positioned between plasma 88A and filter assembly 12A.

[0063] In operation, when light radiation 84A, including in-band light (e.g., extreme ultraviolet light) and out-of-band light, emitted by plasma 88A is incident on filter assembly 12A, filter assembly 12A can remove out-of-band light while allowing in-band light (e.g., extreme ultraviolet light) to pass through. Removing out-of-band light is beneficial because heat from the out-of-band light (which may exist in the range of 100 nm to 800 nm and >1000 nm) can degrade subsequent mirrors, such as mirror 100A. Over time, the filter element of filter assembly 12A may degrade, for example, due to oxidation or the formation of holes penetrating therein. Oxidation can lead to a decrease in in-band light brightness. Holes in the filter element can allow out-of-band light to pass through to subsequent mirrors, which may cause the mirrors to heat up and damage them. For example, heating can increase the formation of oxides, hydrocarbons, or both on the surface of the affected mirror (e.g., mirror 100A). The addition of oxide or hydrocarbon films on the reflectors 100A and 110A of the illuminator 140A or projection optics box 130A can reduce the brightness within the band, thereby reducing the output of the system 10A.

[0064] In some embodiments, a filter monitoring system or a portion thereof is located within the light source 120A. The filter monitoring system may include a first sensor 74A and a second sensor 76A. The filter monitoring system is operable to determine whether the filter element of the filter assembly 12A has been degraded.

[0065] In operation, the filtered light 84AF, including the inner band light, is generated by removing the outer band light from the first light 84A through a filter assembly 12A positioned between or after the plasma 88A and the focal point 87A. Before generating the filtered light 84AF, a first portion 841A of the first light 84A is received by a first sensor 74A. After generating the filtered light 84AF, a second portion 843A of the filtered light 84AF is received by a second sensor 76A. As depicted in FIG1B, the first sensor 74A may be positioned to receive the first portion 841A (which is a part of the first light 84A) incident on the filter assembly 12A, and the second sensor 76A may be positioned to receive the second portion 843A emitted from the filter assembly 12A. In some embodiments, the first and second sensors 74A, 76A are positioned on different (e.g., opposite) walls of the light source 120A. In some embodiments, the first and second sensors 74A, 76A are positioned on the same wall of the light source 120A.

[0066] In some embodiments, in addition to or instead of obtaining the second portion 843A, the output light 847A is received from the projection optics box 130A by an image sensor. The output light 847A may also be referred to as the "second portion". The image sensor may be positioned on or instead of the wafer stage 24A. For example, the wafer stage 24A may be moved from a processing position performing semiconductor processing (e.g., lithography) to another position, and the image sensor may be moved to the vicinity of the processing position or the processing position previously occupied by the wafer stage 24A to perform the detection of the output light 847A.

[0067] In operation, a first sensor 74A is operable to generate a first luminance value associated with a first portion 841A, and a second sensor 76A or an image sensor is operable to generate a second luminance value associated with a second portion 843A or an output light 847A, respectively. A luminance difference can then be determined based on the first and second luminance values. For example, the luminance difference can be determined by subtracting the second luminance value from the first luminance value. The filtered light 84AF substantially excludes out-of-band light. When the first sensor 74A is sensitive to out-of-band light in addition to in-band light, for example, the first luminance measured by the first sensor 74A may have a portion associated with out-of-band light. When calculating the luminance difference, the portion associated with out-of-band light can be removed, for example, by software. In some embodiments, the first sensor 74A is sensitive to in-band light but attenuated or completely insensitive to out-of-band light. In these embodiments, the portion associated with out-of-band light can be removed by the first sensor 74A rather than by software.

[0068] Based on the brightness difference, it can be determined whether the filter element of the filter assembly 12A has been degraded. For example, it can be determined whether the brightness difference exceeds a threshold. If the brightness difference does not exceed the threshold, it can be determined that the filter element has not been degraded, and the system 10A can perform semiconductor processing (e.g., lithography) on the semiconductor wafer. If the brightness difference exceeds the threshold, it can be determined that the filter element has been degraded, and maintenance operations, such as removing, replacing, or repairing the filter element, can be performed on the filter assembly.

[0069] The lithography exposure system 10A may include or be integrated with (or coupled to) other modules, such as a cleaning module designed to supply hydrogen to the light source 120A. Hydrogen helps reduce contamination in the light source 120A. Further description of the light source 120A is provided with reference to FIG1C.

[0070] Figure 1C schematically illustrates a light source 120A according to various embodiments. In some embodiments, the light source 120A employs a dual-pulse laser-produced plasma (LPP) mechanism to generate plasma 88A and further generate extreme ultraviolet radiation 84A from plasma 88A. The light source 120A includes a droplet generator 30, a droplet receiver 35, a laser generator 50, a laser-produced plasma (LPP) collecting mirror 60A (also referred to as "collecting mirror 60A"), a monitoring device 70, and a controller 90. Some or all of the above-described components of the light source 120A can be maintained under vacuum. It should be understood that components of the light source 120A may be added or omitted and should not be limited to this embodiment.

[0071] The droplet generator 30 is configured to generate a plurality of droplets 82 (which may be elongated) of target fuel 80 into an excitation region in which at least one laser pulse 51 from the laser generator 50 strikes the droplets 82. In one embodiment, the target fuel 80 comprises tin (Sn). In one embodiment, the droplets 82 may be formed into an elliptical shape. In one embodiment, the droplets 82 are generated at a rate of about 50 kHz and introduced into the excitation region of the light source 120A at a speed of about 70 meters per second (m / s). Other materials may also be used for the target fuel 80, such as tin-containing liquid materials, such as eutectic alloys containing tin, lithium (Li), and xenon (Xe). The target fuel 80 in the droplet generator 30 may be in the liquid phase.

[0072] Laser generator 50 is configured to generate at least one laser pulse to allow the conversion of droplet 82 into plasma 88A. In some embodiments, laser generator 50 is configured to generate laser pulse 51 toward illumination point 52 to convert droplet 82 into plasma 88A that generates light radiation 84A. Laser pulse 51 is guided through window (or lens) 55 and irradiates droplet 82 at illumination point 52. Window 55 is formed in collecting mirror 60A and employs a suitable material that is substantially transparent to laser pulse 51. Droplet receiver 35 captures and collects unused droplet 82 and / or scattering material of droplet 82 generated by laser pulse 51 striking droplet 82.

[0073] Plasma emits light radiation 84A, which is collected by a collecting mirror 60A and directed toward a focal point 87A. The collecting mirror 60A further reflects and focuses the light radiation 84A for a lithography process performed by an exposure tool. In some embodiments, the collecting mirror 60A has an optical axis 61 parallel to the direction of the laser pulse 51. In some embodiments, the collecting mirror 60A includes at least two concentrically arranged and physically separated collecting mirror portions. The collecting mirror 60A may include a container wall 65 to which a first pump 66 and a second pump 68 are attached. In some embodiments, the first pump 66 and the second pump 68 include a scrubber configured to remove particles and / or gases from the collecting mirror 60A. The first pump 66 and the second pump 68 may be collectively referred to herein as "pumps 66, 68".

[0074] In some embodiments, laser generator 50 is a carbon dioxide (CO2) laser source. In some embodiments, laser generator 50 is used to generate a single-wavelength laser pulse 51. The laser pulse 51 is transmitted through optical components to focus and determine the incident angle of the laser pulse 51. In some embodiments, the spot size of the laser pulse 51 is approximately 200-300 μm, for example, 225 μm. The laser pulse 51 is generated with a specific drive power to meet wafer production targets, such as a throughput of 125 wafers per hour (WPH), although higher WPHs can be achieved, for example, by using a collection mirror 60A, whose larger surface area can increase throughput. In some embodiments, laser pulse 51 is equipped with a drive power of approximately 23 kW. In various embodiments, the drive power of laser pulse 51 is at least 20 kW, for example, 27 kW.

[0075] Monitoring device 70 is configured to monitor one or more conditions in light source 120A to generate data for controlling configurable parameters of light source 120A. In some embodiments, monitoring device 70 includes a metrology tool 71 and an analyzer 73. When metrology tool 71 is configured to monitor conditions of droplets 82 supplied by droplet generator 30, the metrology tool may include an image sensor, such as a charge-coupled device (CCD), complementary metal-oxide-semiconductor (CMOS) sensor, or the like. Metering tool 71 generates a monitoring image including an image or video of droplets 82 and transmits the monitoring image to analyzer 73. When metrology tool 71 is configured to detect the energy or intensity of light radiation 84A generated by droplets 82 in light source 120A, metrology tool 71 may include multiple energy sensors. Energy sensors may be any suitable sensor capable of observing and measuring electromagnetic radiation energy in the ultraviolet region. In some embodiments, metrology tool 71 may include, supplement, or replace the first sensor 74A.

[0076] The analyzer 73 is configured to analyze signals generated by the metering instrument 71 and output detection signals to the controller 90 based on the analysis results. For example, the analyzer 73 includes an image analyzer. The analyzer 73 receives data related to images transmitted from the metering instrument 71 and performs an image analysis procedure on the image of the droplet 82 in the excitation region. Afterwards, the analyzer 73 sends analysis-related data to the controller 90. The analysis may include flow path error or position error.

[0077] In some embodiments, two or more metering instruments 71 are used to monitor different conditions of the light source 120. One is configured to monitor the conditions of the droplets 82 supplied by the droplet generator 30, and another is configured to detect the energy or intensity of the extreme ultraviolet light 84 generated by the droplets 82 in the light source 120. In some embodiments, the metering instrument 71 is a final focus module (FFM) and is positioned in the laser generator 50 to detect the light reflected from the droplets 82.

[0078] The controller 90 is configured to control one or more elements of the light source 120A. In some embodiments, the controller 90 is configured to drive the droplet generator 30 to generate droplets 82. Furthermore, the controller 90 is configured to drive the laser generator 50 to emit laser pulses 51. The generation of the laser pulses 51 may be controlled by the controller 90 to be associated with the generation of the droplets 82, so that the laser pulses 51 sequentially strike each droplet 82.

[0079] In some embodiments, the droplet generator 30 includes a storage tank 31 and a nozzle assembly 32. The storage tank 31 is configured to contain target fuel 80. In some embodiments, a gas line 41 is connected to the storage tank 31 for introducing pumping gas (e.g., argon) from a gas source 40 into the storage tank 31. The pressure in the storage tank 31 can be manipulated by controlling the gas flow in the gas line 41. For example, when gas is continuously supplied to the storage tank 31 through the gas line 41, the pressure in the storage tank 31 increases. As a result, the target fuel 80 in the storage tank 31 can be expelled from the storage tank 31 in the form of droplets 82.

[0080] Figure 1D illustrates a schematic diagram of the optical path 15 of systems 10, 10A according to some embodiments. The optical path 15 is described primarily with reference to system 10 depicted in Figure 1A, and with appropriate reference to Figures 1B and 1C to understand the optical path 15 of system 10A. The optical path 15 of system 10A is similar to that of system 10 in many respects.

[0081] In Figure 1D, optical path 15 begins with the emission of light radiation 84 (or light radiation 84A) generated by plasma 88 (or plasma 88A). Light radiation 84 includes in-band light 84IB (which may be extreme ultraviolet light) and out-of-band light 84OOB (which may be or include infrared light, such as far-infrared light).

[0082] The filter assembly 12 removes (e.g., partially or entirely) the out-of-band light 84OOB and allows the in-band light 84IB to transmit. The in-band light 84IB emitted from the filter assembly 12 is included in or is the filter light 84F. In some embodiments, the filter light 84F (or filter light 84AF) may include a portion of the out-of-band light 84OOB. In some embodiments, the ratio of the out-of-band light 84OOB emitted from the filter assembly 12 to the out-of-band light 84OOB incident on the filter assembly 12 does not exceed about 10%, about 5%, or about 1%.

[0083] In system 10, filtered light 84F is incident on and reflected by collecting mirror 60. In system 10A, filtered light 84AF is incident on and reflected by reflecting mirror 100A of illuminator 140A.

[0084] Filtered light 84F emitted from illuminator 140 is incident on and reflected by the screen 18. Patterned light 84P carrying the pattern of the screen 18 is then incident on and reflected by the mirror 110 of projection optics box 130.

[0085] Patterned light 84P emitted from projection optics 130 is incident on image sensor 26. In some embodiments, patterned light 84P is incident on wafer 22A positioned on wafer stage 24A.

[0086] Typically, filter assembly 12 or filter assembly 12A is positioned along optical path 15 between an extreme ultraviolet light emitting source and a reflector following the light source along optical path 15. For example, in system 10 described with reference to FIG1A, filter assembly 12 is positioned between plasma 88 and collecting mirror 60. In another example, in system 10A described with reference to FIGS. 1B and 1C, filter assembly 12A is positioned between plasma 88A and a first reflector 100A of illuminator 140A, which follows collecting mirror 60A along optical path 15.

[0087] Figure 2A illustrates a schematic diagram of a filter assembly 200 according to some embodiments. The filter assembly 200 is an embodiment of filter assembly 12, filter assembly 12A, or both.

[0088] The filter assembly 200 includes a frame 220 and filter elements 210 positioned on or therein on the frame 220. The frame 220 may be or include a rigid material, such as metal, which may include stainless steel, aluminum, or the like. In some embodiments, the rigid material is ceramic, a non-reactive polymer, or other suitable material.

[0089] The filter element 210 is or includes a sheet comprising multiple layers. The thickness of the filter element 210 is no more than about 500 nanometers (nm). In some embodiments, the thickness is no more than about 150 nanometers. Embodiments of the filter element 210 are described in more detail with reference to FIG2B-2D.

[0090] The filter element 210 may be mounted on or within the frame 220. In some embodiments, both the frame 220 and the filter element 210 have a circular profile in a plane formed by a first direction D1 and a second direction D2 perpendicular to the first direction D1. The filter element 210 is exposed by the frame 220. The frame 220 may be annular and may have an outer diameter and an inner diameter. The filter element 210 may have a diameter exceeding the inner diameter but not exceeding the outer diameter. In some embodiments, the frame 220 comprises two rings stacked along a third dimension perpendicular to the first and second directions D1, D2. The filter element 210 may be secured between the two rings of the frame 220, for example, by adhesive, pressure (e.g., due to fastening screws or clamps), or the like.

[0091] In addition to securing the filter element 210 in place, the frame 220 can also help reduce or eliminate waviness or other non-uniformities of the filter element 210. In some embodiments, adjustable rollers may be included in the frame 220 for fine-tuning the tension of the filter element 210. Mechanisms such as winches or screw-driven systems may be included to apply and adjust tension evenly. Before final assembly of the filter assembly 200, the filter element 210 may be pre-stretched to eliminate initial waviness. This may include stretching the filter element 210 onto another, slightly larger frame to flatten it before final installation. In some embodiments, a brief heat treatment may be performed to improve flatness by allowing the filter element 210 to settle to a flat state under controlled conditions. In some embodiments, applying vibration to the filter element 210 may help it settle to a flat state. In some embodiments, a vacuum environment may help flatten the filter element 210, particularly when the filter element 210 can be mounted on another substrate via differential pressure.

[0092] Figures 2B, 2C and 2D illustrate schematic diagrams of filter element 210 according to some embodiments.

[0093] In Figure 2B, the filter element 210 has a rectangular or square profile in the plane formed by the first and second directions D1, D2. The filter element 210 may have a width W1, a length L1, and a thickness or height H1. The thickness H1 may be along a third direction D3 perpendicular to the first and second directions D1, D2. In some embodiments, the width W1 and the length L1 may each have a size ranging from about 1 centimeter (cm) to about 15 centimeters. In some embodiments, the thickness H1 has a size not exceeding about 1 micrometer (µm), for example, less than about 500 nanometers, about 150 nanometers, or other suitable values. In some embodiments, the width W1 and the length L1 have the same size, such that the profile of the filter element 210 is square. In some embodiments, the width W1 and the length L1 have different sizes, such that the profile of the filter element 210 is rectangular.

[0094] In Figure 2C, the filter element 210 has a circular profile in the plane formed by the first and second directions D1, D2. The filter element 210 may have a diameter D210 and a thickness or height H1 (not separately shown in Figure 2C). In some embodiments, the diameter D210 may have a size ranging from about 1 cm to about 15 cm. In some embodiments, the thickness H1 has a size not exceeding about 1 micrometer (µm), for example less than about 500 nanometers, about 150 nanometers, or other suitable values.

[0095] In Figure 2D, the filter element 210 has an elliptical profile in the plane formed by the first and second directions D1 and D2. The filter element 210 may have a major diameter M210, a minor diameter N210, and a thickness or height H1 (not separately indicated in Figure 2D). In some embodiments, the major diameter M210 and the minor diameter N210 may each have dimensions ranging from about 1 cm to about 15 cm. In some embodiments, the thickness H1 has a dimension not exceeding about 1 micrometer (µm), for example, less than about 500 nanometers, about 150 nanometers, or other suitable values. In some embodiments, the ratio of the major diameter M210 to the minor diameter N210 exceeds about 1.02.

[0096] Figures 3A and 3B illustrate schematic cross-sectional side views of a filter element 300 according to some embodiments. The filter element 300 is one embodiment of the filter element 200 described with reference to Figures 2A-2D.

[0097] In Figure 3A, the filter element 300 includes a zirconium substrate 310, a top cover layer 330 on the zirconium substrate 310, and an optional transition metal substrate 320 between the zirconium substrate 310 and the top cover layer 330.

[0098] The zirconium substrate 310 is operable to transmit light radiation in the extreme ultraviolet (EUV) spectrum while filtering light radiation outside the EUV spectrum. For example, the zirconium substrate 310 is operable to allow photons of inner-band light 84IB to pass through, while photons of outer-band light 84OOB are absorbed, reflected, or both. The zirconium substrate 310 may be or include zirconium, zirconium disilicide (ZrSi2), combinations thereof, or the like. In some embodiments, the zirconium substrate 310 has a thickness H310 in the range of about 30 nanometers to about 350 nanometers. In some embodiments, the thickness H310 of the zirconium substrate 310 is about 70 nanometers.

[0099] The transition metal substrate 320 is operable to remove light radiation beyond the extreme ultraviolet (EUV) spectrum, which can be achieved through reflection, absorption, or both. In some embodiments, the multilayer structure including the zirconium substrate 310 and the transition metal substrate 320 is operable to generate multilayer interference, such that reflections at the interfaces between them cause destructive interference to non-UV wavelengths. The transition metal substrate 320 may be or include molybdenum, niobium, molybdenum disilicide (MoSi2), yttrium, scandium, alloys thereof, combinations thereof (e.g., multilayers thereof), or the like. In some embodiments, the transition metal substrate 320 has a thickness H320 in the range of about 10 nanometers to about 100 nanometers. In some embodiments, the thickness H320 of the transition metal substrate 320 is about 30 nanometers. The thickness of the multilayer structure including the zirconium substrate 310 and the transition metal substrate 320 does not exceed about 480 nanometers. In some embodiments, the transition metal substrate 320 is not included, such that the top cap layer 330 is in direct contact with the zirconium substrate 310.

[0100] The capping layer 330 is operable to prevent oxidation of the underlying layer, such as a transition metal substrate 320, a zirconium substrate 310, or both. In some embodiments, the capping layer 330 may be or include a silicon-based dielectric material, such as silicon carbide, silicon dioxide, silicon nitride, or the like. In some embodiments, the capping layer 330 has a thickness H330 in the range of about 3 nanometers to about 20 nanometers. In some embodiments, the thickness H330 of the capping layer 330 is about 5 nanometers. A thickness H330 exceeding about 20 nanometers may attenuate in-band light radiation in the extreme ultraviolet spectrum.

[0101] In some embodiments, thickness H310 exceeds thickness H320, and thickness H320 exceeds thickness H330.

[0102] In some embodiments, the materials between adjacent pairs of zirconium substrate 310, transition metal substrate 320, and top cover layer 330 may be mixed. In some embodiments, the thickness of the mixture does not exceed about 3 nanometers. For example, a thin zirconium and molybdenum mixed layer may be formed at the interface between zirconium substrate 310 and transition metal substrate 320, and the thickness of this thin layer does not exceed about 3 nanometers.

[0103] In system 10 or system 10A, when the filter element 300 is included in filter assembly 12 or filter assembly 12A, the top cover layer 330 faces or is close to an extreme ultraviolet light emission source, such as plasma 88 or plasma 88A.

[0104] In FIG. 3B, the filter element 300 is similar in most respects to that described with reference to FIG. 3A. As shown in FIG. 3B, in some embodiments, the filter element 300 may include a multilayer structure having at least two zirconium substrates 310A, 310B and at least two transition metal substrates 320A, 320B, instead of a multilayer structure including a single zirconium substrate 310 and a single transition metal substrate 320. For example, the filter element 300 may include a first zirconium substrate 310A, a second zirconium substrate 310B, a first transition metal substrate 320A, and a second transition metal substrate 320B. A top cover layer 330 is located on the second transition metal substrate 320B, which is located on the second zirconium substrate 310B, which is located on the first transition metal substrate 320A, and the first transition metal substrate 320A is located on the first zirconium substrate 310A. The first height H310A and the second height H310B of the first and second zirconium substrates 310A and 310B exceed the third height H320A and the fourth height H320B of the first and second transition metal substrates 320A and 320B, respectively, and the third height H320A and the fourth height H320B further exceed the fifth height H330 of the top cover layer. Figure 3B depicts two zirconium substrates 310A and 310B and two transition metal substrates 320A and 320B. In some embodiments, the multilayer structure includes additional zirconium substrates and transition metal substrates, such that the multilayer structure includes three, four, five or more zirconium substrates and transition metal substrates.

[0105] Figure 4A illustrates a schematic diagram of a filter component degradation detection system 400 (or simply "detection system 400") according to some embodiments.

[0106] The detection system 400 includes a first sensor 474 and a second sensor 426. The first sensor 474 is operable to determine a first brightness associated with a first light 484 incident on a filter assembly 412, which may be filter assembly 12, filter assembly 12A, filter assembly 200, or other similar filter assembly. The second sensor 426 is operable to determine a second brightness associated with a second light 486 emitted from the filter assembly 412. As the filter element of the filter assembly 412 degrades, the second brightness may decrease, possibly as a result of filter element oxidation. Therefore, the brightness difference between the first and second brightness may increase. In response to a decrease in second brightness, an increase in the brightness difference, or both, it can be determined whether the filter assembly 412 has degraded to the point where rework, repair, or replacement of the filter assembly 412 or its filter element is required.

[0107] One or more thresholds can be selected to determine whether the filter assembly 412 has been degraded. In some embodiments, a first threshold related to the second brightness is selected. In response to the second brightness exceeding the first threshold, it can be determined that the filter assembly 412 has not been degraded and semiconductor processing can continue. In response to the second brightness not exceeding the first threshold, it can be determined that the filter assembly 412 has been degraded and semiconductor processing can be stopped; the filter assembly 412 can be reworked, replaced, repaired, or a combination thereof. In some embodiments, the decrease in second brightness over time can be measured instead of comparing the second brightness to the first threshold. For example, an initial second brightness can be determined immediately after the filter assembly 412 is installed, and then the second brightness can be measured continuously or periodically and compared with the initial second brightness. In response to the decrease in second brightness exceeding the threshold, it can be determined that the filter assembly 412 has been degraded, and one or more of the aforementioned actions can be taken. The threshold can be a percentage of brightness lost over time. In some embodiments, the threshold can be in the range of about 5% to about 20%, or other suitable percentages.

[0108] In some embodiments, a second threshold related to the brightness difference is selected. If the brightness difference does not exceed the second threshold, it can be determined that the filter component 412 has not been degraded and the semiconductor processing can continue. If the brightness difference exceeds the second threshold, it can be determined that the filter component 412 has been degraded and the semiconductor processing can be stopped; the filter component 412 can then be reworked, replaced, repaired, or a combination thereof.

[0109] Figure 4B illustrates a schematic diagram of a filter component degradation detection system 400A (or simply "detection system 400A") according to some embodiments.

[0110] In some embodiments, the filter assembly 412 is positioned within or at one end of the tube 410. The tube 410 may be a transport line 14 as described with reference to FIG1A. The filter assembly 412, located within or abutting one end of the tube 410, physically separates the first chamber 414 from the second chamber 416. The first chamber 414 may be a first chamber 122, and the second chamber 416 may be a second chamber 124, as described with reference to FIG1A. The first chamber 414 may have a first pressure Pa, and the second chamber 416 may have a second pressure Pb different from the first pressure Pa. In some embodiments, the second pressure Pb exceeds the first pressure Pa.

[0111] The detection system 400A includes a differential pressure sensor 470 operable to determine a first pressure Pa and a second pressure Pb. In some embodiments, the differential pressure sensor 470 includes a first pressure sensor 471, a second pressure sensor 473, and a controller 475. The first pressure sensor 471 is mounted on the tube 410 near a first chamber 414 and determines a first pressure Pa in the first chamber 414, which may include generating a first pressure value associated with the first chamber 414. The second pressure sensor 473 is mounted on the tube 410 near a second chamber 416 and determines a second pressure Pb in the second chamber 416, which may include generating a second pressure value associated with the second chamber 416. The controller 475 communicates data or electrically with the first and second pressure sensors 471 and 473 and is operable to determine a pressure difference based on the first and second pressure values. For example, the pressure difference may be equal to the second pressure value minus the first pressure value.

[0112] During operation, as the filter element 412 degrades, perforation may occur due to high-speed impact of tin debris on the filter element. Sufficient perforation of the filter element can lead to a reduction in the pressure differential. That is, because the perforation of the filter element forms an opening connecting the first chamber 414 and the second chamber 416, the first pressure Pa and the second pressure Pb may be approximately equal.

[0113] In response to a pressure differential value decreasing below a threshold, it can be determined that the filter assembly 412 has been degraded, and the filter assembly 412 can be replaced, repaired, reworked, or similar treatment can be performed. In some embodiments, the threshold may be slightly higher than zero. In some embodiments, the threshold may be a percentage of the expected pressure differential value associated with a substantially non-perforated filter assembly 412. For example, this percentage may be in the range of about 0% to about 80%. That is, a pressure differential value decreasing from the expected pressure differential value by more than about 20% may lead to a determination that the filter assembly 412 has been degraded, and the filter assembly 412 may be replaced, repaired, reworked, or similar treatment can be performed.

[0114] Figure 4C shows a schematic diagram of a filter component degradation detection system 400B according to some embodiments.

[0115] In some embodiments, focus 430 is associated with light radiation 486 incident on a subsequent reflector 460, such as reflector 100 of illuminator 140 or reflector 110 of POB 130. The position of reflector 460 can be adjusted back and forth along axis 461 to correspond to focus 430. The position of reflector 460 can be controlled by an actuator controlled by a controller. Reflector 460 may initially be positioned at a first focus 420, which may be the expected or initial position associated with a substantially unoxidized filter assembly 412. Due to oxidation during degradation of filter assembly 412, light radiation 486 may have a second focus 430 displaced relative to the first focus 420, as shown in FIG4C. The position of reflector 460 may gradually shift from the first focus 420 to the second focus 430 over time, achieved by a control algorithm or autofocus algorithm executed by the controller. Displacement O1 is depicted in FIG4C, which is a distance measurement between the first focus 420 and the second focus 430.

[0116] During operation, a threshold corresponding to the degradation of the filter component 412 can be selected. In response to the displacement O1 exceeding the threshold, it can be determined that the filter component 412 has been degraded, and the filter component 412 can be replaced, repaired, reworked, or subjected to similar processing. In response to the displacement O1 not exceeding the threshold, it can be determined that the filter component 412 has not been degraded, and semiconductor processing can be performed while the filter component 412 is in place.

[0117] Figure 5 illustrates a schematic diagram of a filter component monitoring system or "system" 500 according to some embodiments. System 500 includes at least one of the following: a set of filter component monitoring devices 504, facility equipment 502, a computer 514, a filter component status system 506, or one or more client devices 508. The set of filter component monitoring devices 504 includes filter component monitoring devices distributed throughout the facility. The filter component monitoring devices are used to determine measurements associated with devices and / or other equipment in the facility (e.g., systems 10, 10A as shown with reference to Figures 1A-1D). In some embodiments, the filter component monitoring devices are used to determine measurements associated with filter components 12, 12A, 200, 412 as shown with reference to Figures 1A-4C.

[0118] In some embodiments, the filter assembly monitoring device 504 transmits a set of monitoring signals 512 to a computer 514. In some embodiments, each of the monitoring signals 512 is transmitted by a monitoring device (e.g., first and second sensors 74, 76) of the filter assembly monitoring device 504 in the facility system.

[0119] In some embodiments, the set of monitoring signals 512 includes a first monitoring signal from a first sensor 74. In some embodiments, the first sensor 74 includes a wireless communication module that wirelessly transmits the first monitoring signal to a computer 514. In some embodiments, the first sensor 74 transmits the first monitoring signal to the computer 514 via a wired connection between the first sensor 74 and the computer 514. In some embodiments, the first monitoring signal indicates the brightness associated with a first portion 841 sampled by the first sensor 74.

[0120] In some embodiments, the set of monitoring signals 512 includes a second monitoring signal from the second sensor 76. In some embodiments, the second monitoring signal indicates the brightness associated with a second portion 843 sampled by the second sensor 76. The first monitoring signal may indicate a first brightness associated with a first light (e.g., light radiation 84), and the second monitoring signal may indicate a second brightness associated with a second light (e.g., filtered light 84F). The first light and the second light may be located on either side of the filtering components associated with the first and second sensors 74, 76.

[0121] In some embodiments, computer 514 controls display panel 520, which includes a set of status indicators associated with devices in the facility system (e.g., first, second, third, and fourth sensors indicated by "IS1", "IS2", "PS1", and "MS1", respectively). The first and second sensors may be image sensors, such as image sensor 26. The third sensor may be a differential pressure sensor, such as differential pressure sensor 470. The fourth sensor may be a motion sensor, such as the controller described with reference to FIG4C. In some embodiments, the indicators in the set of status indicators include lights, such as indicator lights, for indicating whether a corresponding device is associated with a degraded filter assembly, wherein a light in a first state indicates that the corresponding device is associated with a degraded filter assembly, and / or a light in a second state indicates that the corresponding device is not associated with a degraded filter assembly. In some embodiments, display panel 520 includes a display configured to display an alarm indicating the monitoring status of one or more detected filter assemblies of one or more devices. In some embodiments, the first state corresponds to a first color emitted by the light, such as red or another color, and the second state corresponds to a second color emitted by the light, such as green or another color. The set of status indicators includes at least one of the following: a first indicator "IS1" associated with a first device (e.g., first sensor 74), a second indicator "IS2" associated with a second device (e.g., second sensor 76), a third indicator "PS1" associated with a third device (e.g., differential pressure sensor 470), a fourth indicator "MS1" associated with a fourth device (e.g., controller as shown in FIG4C), or other indicators.

[0122] In some embodiments, computer 514 provides one or more first signals 510 to facility equipment 502. In some embodiments, the one or more first signals 510 are used to control at least some devices in facility equipment 502, such as the facility's lithography system and / or other devices of the facility. In some embodiments, the one or more first signals 510 are generated using a signal generator of computer 514. The one or more first signals 510 may indicate that the filter components of the lithography system have been degraded. In some embodiments, computer 514 wirelessly transmits one or more first signals 510 to facility equipment 502, for example, using a wireless communication device of computer 514. In some embodiments, computer 514 transmits one or more first signals 510 to facility equipment 502 via a physical connection between computer 514 and facility equipment 502. In some embodiments, computer 514 transmits one or more first signals 510 to a controller that controls one or more operations of the lithography system. In some embodiments, the controller controls the removal of filter components, for example, performed by a robotic arm.

[0123] In some embodiments, computer 514 transmits a second signal 518 to filter assembly status system 506. The second signal 518 is generated using a signal generator of computer 514. In some embodiments, the second signal 518 indicates at least one of the following: (i) the monitoring status of the filter assembly group, (ii) a list of devices determined to have degraded filter devices, or (iii) other information. In some embodiments, computer 514 wirelessly transmits the second signal 518 to status system 506, for example, using a wireless communication device of computer 514. In some embodiments, computer 514 transmits the second signal 518 to status system 506 via a physical connection between computer 514 and status system 506. In some embodiments, status system 506 triggers an alarm function based on the second signal 518. In some embodiments, status system 506 triggers an alarm function based on the second signal 518 indicating that a filter device has been degraded. In some embodiments, an alarm message is displayed on the display of status system 506 in response to triggering the alarm function. The alarm message includes at least one of the following: an indication that the filter has been degraded, an indication of the lead time for preventative maintenance, an indication that the associated lithography system has stopped operating (e.g., until the filter is replaced), or other indications. In some embodiments, an alarm sound is output via a speaker connected to the filter assembly status system 506 in response to triggering the alarm function.

[0124] In some embodiments, computer 514 transmits a third signal 516 to one or more client devices 508. The one or more client devices 508 include at least one of a telephone, smartphone, mobile phone, landline, laptop, desktop computer, hardware, or other type of client device. The third signal 516 is generated using a signal generator of computer 514. In some embodiments, the third signal 516 indicates at least one of the following: (i) the monitoring status of the set of filter components, (ii) a list of devices determined to be associated with a degraded filter component, or (iii) other information. In some embodiments, computer 514 wirelessly transmits the third signal 516 to the client devices among the one or more client devices 508, for example, using a wireless communication device of computer 514. In some embodiments, computer 514 transmits the third signal 516 to the client devices among the one or more client devices 508 via a physical connection between computer 514 and the client devices. In some embodiments, the third signal 516 includes at least one of a message transmitted in response to the detection of a degraded filter component, such as an email, a text message, etc. In some embodiments, in response to the detection of a degraded filter device, a telephone call is made to a client device (e.g., a landline or mobile phone) among the one or more client devices 508 using the dialer of computer 514.

[0125] In some embodiments, monitoring signal group 512 is used as feedback, and computer 514 controls the operation of facility equipment 502 based on this feedback. In some embodiments, computer 514 controls the operation of facility equipment 502 based on measurements provided by monitoring signal group 512. In some embodiments, the operation of facility equipment 502 is controlled using one or more first signals 510. In some embodiments, the signals in one or more first signals 510 indicate one or more instructions.

[0126] In some embodiments, system 10 of facility 502, in response to receiving a signal indicating that a filter device has been degraded (one or more first signals 510), performs at least one of the following operations: stops operation, removes or replaces the filter device, or performs another operation. In some embodiments, one or more first signals 510 include a signal transmitted to a machine (e.g., system 10). In some embodiments, the signal instructs the machine to stop operation when the filter device is undergoing preventative maintenance. In some embodiments, the signal allocates one or more resources (e.g., manpower, robots, one or more tools, replacement components, etc.) to system 10 to replace the filter device.

[0127] Figure 6 is a flowchart illustrating a method 600 for operating a system having a filter device according to some embodiments.

[0128] Figure 6 illustrates method 600 according to some embodiments.

[0129] At 602, plasma from the light source of the semiconductor processing tool generates first light. The first light includes in-band light within the extreme ultraviolet spectrum and out-of-band light outside the extreme ultraviolet spectrum.

[0130] At 604, before the filtered light is generated, the first sensor receives a first portion of the first light.

[0131] In 606, a filter assembly with a filter element generates filtered light including in-band light by removing out-of-band light from the first light. The filter element includes a zirconium substrate and a transition metal substrate on the zirconium substrate. The filter assembly is located between the plasma and the collecting mirror.

[0132] At 608, after the filtered light is generated, the second sensor receives a second portion of the filtered light.

[0133] At 610, a first brightness value associated with the first part is generated, and a second brightness value associated with the second part is generated.

[0134] In 612, a brightness difference is generated based on the first brightness value and the second brightness value.

[0135] At 614, it is determined whether the brightness difference exceeds the threshold.

[0136] At 616, in response to the brightness difference exceeding the threshold, maintenance operations are performed on the filter assembly.

[0137] In 618, in response to the brightness difference not exceeding the threshold, the semiconductor processing tool performs semiconductor processing on the semiconductor wafer.

[0138] Figure 7 is a flowchart illustrating method 700 according to some embodiments.

[0139] Figure 7 illustrates method 700 according to some embodiments.

[0140] In 702, method 700 includes generating first light by plasma from a light source of a semiconductor processing tool, the first light including in-band light within the extreme ultraviolet spectrum and out-of-band light outside the extreme ultraviolet spectrum.

[0141] In method 704, method 700 includes generating filtered light including in-band light by removing out-of-band light from a first light source using a filter assembly in direct contact with the tube. The filter assembly has a filter element comprising a zirconium substrate and a transition metal substrate located on the zirconium substrate.

[0142] In 706, method 700 includes determining whether the filter component has been degraded.

[0143] In 708, method 700 includes performing maintenance operations on the filter assembly in response to filter assembly degradation.

[0144] In 710, method 700 includes performing a semiconductor process on a semiconductor wafer by a semiconductor processing tool in response to the filter component not being degraded.

[0145] Figure 8 illustrates an example computer-readable medium according to some embodiments, which may contain processor-executable instructions configured to embody one or more of the specified instructions set forth herein.

[0146] One or more embodiments relate to computer-readable media including processor-executable instructions configured to implement one or more of the techniques provided herein. Figure 8 illustrates an example computer-readable medium, where embodiment 800 includes a computer-readable medium 808 (e.g., a CD-R, DVD-R, flash drive, hard disk plate, etc.) having computer-readable data 806 encoded thereon. This computer-readable data 806 then includes a set of processor-executable computer instructions 804 configured to implement one or more of the principles set forth herein when executed by a processor. In some embodiments 800, the processor-executable computer instructions 804 are configured to implement method 802, such as at least some of the methods described above, when executed by a processor. In some embodiments, the processor-executable computer instructions 804 are configured to implement a system, such as at least some of the systems described above, when executed by a processor. Many such computer-readable media configured to operate according to the techniques provided herein will be conceived by those skilled in the art.

[0147] In some embodiments, a method is provided. The method includes: generating first light from plasma of a light source of a semiconductor processing tool, the first light including in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum; generating filtered light including in-band light by removing the out-of-band light from the first light using a filter assembly having a filter element, wherein the filter element includes a zirconium substrate and a transition metal substrate on the zirconium substrate, and the filter assembly is positioned between the plasma and a collecting mirror; receiving a first portion of the first light by a first sensor before generating the filtered light; receiving a second portion of the filtered light by a second sensor after generating the filtered light; generating a first brightness value associated with the first portion; generating a second brightness value associated with the second portion; determining a brightness difference based on the first brightness value and the second brightness value; determining whether the brightness difference exceeds a threshold; performing a semiconductor process on a semiconductor wafer by the semiconductor processing tool in response to the brightness difference not exceeding the threshold; and performing a maintenance operation on the filter assembly in response to the brightness difference exceeding the threshold. In one embodiment, receiving the second portion includes receiving the second portion of the filtered light via a second sensor, the second portion being obtained from a position located between the filter assembly and the collecting mirror. In one embodiment, the semiconductor processing tool includes a mask stage positioned along an optical path from the plasma to the wafer stage, and receiving the second portion includes receiving the second portion of the filtered light via a second sensor, the second portion being obtained from a position along the optical path between the collecting mirror and the mask stage. In one embodiment, the semiconductor processing tool includes a mask stage positioned along an optical path from the plasma to the wafer stage, and receiving the second portion includes receiving the second portion of the filtered light via a second sensor, the second sensor being an image sensor positioned at the wafer stage. In one embodiment, generating the filtered light includes generating the filtered light via the filter assembly, which is in direct contact with an interface tube positioned between a first chamber containing the plasma and a second chamber containing the collecting mirror. In one embodiment, generating the filtered light includes generating the filtered light by means of a light-filtering assembly mounted on the end of the interface tube positioned in the second chamber.

[0148] In some embodiments, a method is provided. The method includes: generating first light from plasma of a light source of a semiconductor processing tool, the first light including in-band light within the extreme ultraviolet spectrum and out-of-band light outside the extreme ultraviolet spectrum; generating filtered light including in-band light by removing the out-of-band light from the first light by a filter assembly of a direct contact tube, the filter assembly having a filter element including a zirconium substrate and a transition metal substrate on the zirconium substrate; determining whether the filter assembly is degraded; performing maintenance operations on the filter assembly in response to the filter assembly being degraded; and performing a semiconductor process on a semiconductor wafer by the semiconductor processing tool in response to the filter assembly not being degraded. In one embodiment, determining whether the filter assembly is degraded includes: generating a first pressure value associated with a first portion of the tube defined on a first side of the filter assembly; generating a second pressure value associated with a second portion of the tube defined on a second side of the filter assembly relative to the first side; determining a pressure difference based on the first pressure value and the second pressure value; determining whether the pressure difference exceeds a threshold; determining that the filter assembly is not degraded in response to the pressure difference exceeding the threshold; and determining that the filter assembly is degraded in response to the pressure difference not exceeding the threshold. In one embodiment, determining whether the filter assembly is degraded includes: generating a displacement value associated with the displacement of a mirror of the semiconductor processing tool from a first position to a second position; determining whether the displacement value exceeds a threshold; determining that the filter assembly is degraded in response to the displacement value exceeding the threshold; and determining that the filter assembly is not degraded in response to the displacement value not exceeding the threshold. In one embodiment, generating the filtered light includes: generating the filtered light by means of the filter assembly having the filter element including a top cover layer, wherein the transition metal substrate is located between the top cover layer and the zirconium substrate. In one embodiment, generating the filtered light includes:

[0149] The filtered light is generated by a filter assembly having a filter element comprising a silicon substrate as the top cover layer. In one embodiment, generating the filtered light includes generating the filtered light by the filter assembly having a filter element comprising the top cover layer, wherein the top cover layer is a silicon substrate comprising a hydrophobic surface. In another embodiment, generating the filtered light includes generating the filtered light by the filter assembly having a filter element comprising a second transition metal substrate and a second zirconium substrate, wherein the second transition metal substrate and the second zirconium substrate are located between the top cover layer and the transition metal substrate.

[0150] In some embodiments, a system is provided. The system includes: a light source operable to generate plasma emitting a first light, the first light comprising in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum; a collecting mirror; a wafer stage, an optical path defined as a first chamber of the light source to the collecting mirror and then to the wafer stage; a dome stage positioned along the optical path between the collecting mirror and the wafer stage; and a filter assembly positioned on the optical path, the filter assembly including a filter element having a first zirconium substrate and a capping layer. In one embodiment, the filter element includes a first transition metal substrate positioned between the first zirconium substrate and the capping layer. In one embodiment, a first thickness of the first zirconium substrate is in the range of substantially 50 nanometers (nm) to substantially 90 nm; a second thickness of the first transition metal substrate is in the range of substantially 20 nm to substantially 40 nm; and a third thickness of the capping layer is in the range of substantially 3 nm to substantially 10 nm. In one embodiment, the light source includes: a housing; a first chamber located within the housing, the first chamber being operable to generate plasma emitting the first light; a second chamber located within the housing, the collecting mirror located within the second chamber; an interface tube extending from the first chamber to the second chamber; a first pressure sensor positioned within the first chamber; and a second pressure sensor positioned within the second chamber. In one embodiment, the filter assembly is positioned within the interface tube. In one embodiment, the filter assembly is mounted at an end of the interface tube, the end being positioned within the second chamber. In one embodiment, the thickness of the filter element does not exceed substantially 150 nm.

[0151] Although the subject matter has been described using language specific to structural features or methodological actions, it is understood that the subject matter of the accompanying request is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as exemplary forms of implementing at least some of the requests.

[0152] This document provides various operations of the embodiments. The order in which some or all of the operations are described should not be construed as implying that these operations must depend on the order. Alternative orderings that benefit from this description will be understood. Furthermore, it should be understood that not all operations must exist in every embodiment provided in this disclosure. Moreover, it will be understood that not all operations are necessary in some embodiments.

[0153] It will be understood that the layers, features, elements, etc., described herein are illustrated with specific dimensions relative to each other, such as structural dimensions or orientations, for the purpose of simplicity and ease of understanding, and in some embodiments, the actual dimensions of these layers, features, elements, etc., are substantially different from those illustrated herein. Furthermore, various techniques exist for forming the layers, regions, features, elements, etc. mentioned herein, such as etching techniques, planarization techniques, implantation techniques, doping techniques, spin coating techniques, sputtering techniques, growth techniques, or at least one of deposition techniques such as chemical vapor deposition (CVD).

[0154] Furthermore, the terms "exemplary" and / or similar terms are used herein to mean as an instance, example, illustration, etc., and are not necessarily advantageous. As used in this application, "or" is intended to mean an inclusive "or" rather than an exclusive "or". Furthermore, unless otherwise specified or clearly indicated from the context to be for the singular form, "a" and "an" as used in this application and the appended claims should generally be interpreted as meaning "one or more". Furthermore, "at least one of A and B" and / or similar terms generally mean A or B or both A and B. Furthermore, in the use of "including," "having," "has," "with," or variations thereof, these terms are intended to be inclusive in a manner similar to the term "includes". Furthermore, unless otherwise specified, "first," "second," or similar terms are not intended to imply temporal state, spatial state, order, etc. Rather, these terms are used only as identifiers, names, etc., of features, elements, items, etc. For example, the first element and the second element usually correspond to element A and element B, or two different or two identical elements, or the same element.

[0155] Furthermore, although this disclosure has been shown and described with respect to one or more embodiments, equivalent changes and modifications will conceive of by those skilled in the art based on their reading and understanding of this specification and the accompanying drawings. This disclosure encompasses all such modifications and changes and is limited only by the scope of the following claims. In particular, with respect to the various functions performed by the aforementioned elements (e.g., elements, resources, etc.), unless otherwise stated, the terms used to describe such elements are intended to correspond to performing the specified functions of the described elements (e.g., functionally equivalent), although no element is structurally equivalent to the structure disclosed. Moreover, while a particular feature of this disclosure may have been disclosed with respect to only one of several embodiments, such feature may be combined with one or more other features of other embodiments, as may be desired and advantageous for any given or particular application.

[0156] 10, 10A, 500, 400, 400A, 400B: Systems, semiconductor processing tools 12, 12A, 200, 412: Filter components 14: Transport pipelines 15: Optical Path 16, 16A: Curtain Stage 18, 18A: Curtain 22, 22A: Wafer 24A: Wafer Stage 26: Image Sensor 30: Droplet generator 31: Storage slot 32: Nozzle assembly 35: Droplet receiver 40: Gas source 41: Gas pipeline 50: Laser Generator 51: Laser Pulse 52:Lighting point 55: Window 60, 60A: Collection mirror 61: Optical axis 65:Container wall 66, 68: Second pump 70: Monitoring device 71: Measuring tools 73: Analyzer 74, 74A, 76, 761, 76A: Second sensor 80: Target fuel 82: Droplets 84AF, 84F: Filter light 84IB: With internal light 84OOB: With external light 84P: Patterned Light 84, 84A: Light 88, 88A: Plasma 100, 100A, 110, 110A, 460: Reflector 120, 120A: Light source 122, 414: First chamber 124, 416: Second chamber 130, 130A: Projection Optical Box 140, 140A: Lighting fixtures 200, 201, 210, 300: Filter elements 220: Frame 310: Zirconium base layer 310A: First Zirconium Base 310A, 310B: Second zirconium base layer 310B: Second Zirconium Base 320: Transition metal base layer 320A: First transition metal base layer 320A, 320B: Second transition metal base layer 320B: Second transition metal base layer 330: Top Cover Layer 410: pipe 420: First Focus 426, 76, 761, 76A: Second sensor 430, 87A: Focus 461: Axis 470: Differential pressure sensor 471: First pressure sensor 471, 473: Second pressure sensor 473: Second pressure sensor 474, 74, 74A: First sensor 475, 90: Controller 486, 84, 84A: Radiation 502: Facilities and Equipment 504: Filter component monitoring device 506: State System 508: Client device 510: First Signal 512: Monitoring signal 514: Computer 516: Third Signal 518: Second Signal 520: Display Panel 600, 700, 802: Methods 800: Example 804: Computer Instruction 808: Computer-readable media 841, 841A: Part 1 843, 843A, 845: Part Two 847, 847A: Output light D1: First Direction D2: Second Direction D3: Third direction D210: Diameter H1: Height H1, H310, H320, H330: Thickness H310B: Second Altitude H320B: Fourth Altitude L1: Length M210: Large Diameter N210: Small diameter O1: Displacement W1: Width

Claims

1. A method of operating a semiconductor processing system, comprising: A first light is generated by plasma from a light source of a semiconductor processing tool. The first light includes in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum. The out-of-band light is removed from the first light by a filter assembly having a filter element to generate filtered light including the in-band light. The filter element includes a zirconium substrate and a transition metal substrate located on the zirconium substrate, and the filter assembly is located between the plasma and a collecting mirror. Before generating the filtered light, a first portion of the first light is received by a first sensor. After generating the filtered light, a second portion of the filtered light is received by a second sensor. A first brightness value associated with the first portion is generated. A second brightness value associated with the second portion is generated. A brightness difference is determined based on the first brightness value and the second brightness value. It is then determined whether the brightness difference exceeds a threshold value. In response to the brightness difference not exceeding the threshold, a semiconductor process is performed on the semiconductor wafer using the semiconductor processing tool; And in response to the brightness difference exceeding the threshold, perform maintenance operations on the filter component.

2. The method of claim 1, wherein the semiconductor processing tool includes a mask stage positioned along an optical path from the plasma to the wafer stage location, and receiving the second portion includes: The second portion of the filtered light is received by the second sensor, the second portion being obtained from a position along the optical path between the collecting mirror and the dome stage or from a position located between the filter assembly and the collecting mirror.

3. A method of operating a semiconductor processing system, comprising: A first light is generated by plasma from a light source of a semiconductor processing tool. The first light includes in-band light within the extreme ultraviolet (EUV) spectrum and out-of-band light outside the EUV spectrum. Filtered light including the in-band light is generated by removing the out-of-band light from the first light using a filter assembly positioned in direct contact with the tube. The filter assembly has a filter element comprising a zirconium substrate and a transition metal substrate on the zirconium substrate. A determination is made as to whether the filter assembly is degraded. In response to the filter assembly being degraded, a maintenance operation is performed on the filter assembly. And in response to the filter assembly not being degraded, a semiconductor process is performed on the semiconductor wafer using the semiconductor processing tool.

4. The method as described in claim 3, wherein determining whether the filter component is degraded includes: A first pressure value is generated in relation to a first portion of the tube defined on a first side of the filter assembly; Generate a second pressure value associated with a second portion of the tube defined on a second side of the filter assembly relative to the first side; determine a pressure difference based on the first pressure value and the second pressure value; determine whether the pressure difference exceeds a threshold; and, in response to the pressure difference exceeding the threshold, determine that the filter assembly has not been degraded. And in response to the pressure difference not exceeding the threshold, it is determined that the filter component has been degraded.

5. The method as described in claim 3, wherein determining whether the filter component is degraded includes: Generate a displacement value related to the displacement of the reflector of the semiconductor processing tool from a first position to a second position; Determine whether the displacement value exceeds the threshold; In response to the displacement value exceeding the threshold, it is determined that the filter component has been degraded; And in response to the displacement value not exceeding the threshold, it is determined that the filter component has not been degraded.

6. The method of claim 3, wherein generating the filtered light comprises: The filtered light is generated by the filter assembly having the filter element including a top cover layer, wherein the transition metal substrate is located between the top cover layer and the zirconium substrate, and the top cover layer is a silicon substrate including a hydrophobic surface.

7. A semiconductor processing system, comprising: A light source, operated to generate plasma emitting a first light, the first light comprising in-band light within the extreme ultraviolet spectrum and out-of-band light outside the extreme ultraviolet spectrum; a collecting mirror; The optical path is defined as from the first chamber of the light source to the collecting mirror, and then to the wafer stage; The stage is positioned along the optical path between the collecting mirror and the wafer stage; and a filter assembly positioned on the optical path, the filter assembly including a filter element, the filter element including: a first zirconium substrate; And the top cover layer.

8. The system of claim 7, wherein the filter element includes a first transition metal substrate positioned between the first zirconium substrate and the top cover layer.

9. The system as claimed in claim 7, wherein the light source comprises: shell; The first chamber is located within the housing and is operated to generate the plasma that emits the first light; The second chamber is located within the outer casing, and the collecting mirror is located within the second chamber; An interface tube extending from the first chamber to the second chamber; a first pressure sensor located in the first chamber; and a second pressure sensor located in the second chamber.

10. The system of claim 9, wherein the filter assembly is located in the interface tube or mounted on an end of the interface tube, the end being located in the second chamber.

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