System and method for vacuum ultraviolet lamp assisted ignition of an oxygen-containing laser sustained plasma source

Abstract

A lighting system includes a gas containment vessel configured to contain a gas. The lighting system also includes one or more pump sources configured to generate one or more pump beams. The lighting system includes an ozone generation unit including one or more illumination sources. The one or more illumination sources are configured to generate an illumination beam of sufficient energy to convert a portion of diatomic oxygen (O2) contained within the gas containment vessel to triatomic oxygen (O3). One or more energy sources are configured to ignite a plasma within the gas contained within the gas containment vessel via absorption of energy of the one or more energy sources by a portion of the triatomic oxygen, wherein the plasma emits broadband radiation.

Description

Technical Field

[0001] This disclosure generally relates to lighting sources, and more specifically, to laser continuous plasma (LSP) sources. Background Technology

[0002] The demand for improved lighting systems for inspecting ever-shrinking semiconductor devices is growing. One such lighting system includes a laser continuous plasma (LSP) lighting system. An LSP lighting system comprises an LSP lamp capable of generating high-power broadband light. The LSP lamp operates by focusing laser radiation into a gas volume to excite the gas into a plasma state. Once ignited, the plasma emits broadband radiation. Typically, an LSP lamp requires electrodes to ignite the plasma, which is then sustained solely by the laser energy. Current LSP lamps are filled with rare gases such as argon, krypton, xenon, or nitrogen. Oxygen cannot be added to LSP lamps containing electrodes because it undergoes severe oxidation during lamp operation. This makes igniting the plasma a complex and expensive process. Furthermore, aligning and maintaining the lighting system is difficult.

[0003] Therefore, it is desirable to provide a system and method that overcomes the shortcomings of the prior methods identified above. Summary of the Invention

[0004] According to one or more embodiments of this disclosure, a system is disclosed. In one embodiment, the system includes a gas containment container configured to contain a gas. In another embodiment, the system includes one or more pump sources configured to generate one or more pump beams for sustaining a plasma within the gas containment container. In another embodiment, the system includes an ozone generating unit comprising one or more illumination sources. In another embodiment, the one or more illumination sources are configured to generate an illumination beam with sufficient energy to convert a portion of diatomic oxygen (O2) contained within the gas containment container into triatomic oxygen (O3). In another embodiment, one or more energy sources are configured to ignite the plasma within the gas contained within the gas containment container by absorbing energy from the one or more energy sources through a portion of the triatomic oxygen, wherein the plasma emits broadband radiation.

[0005] According to one or more embodiments of this disclosure, an apparatus is disclosed. In one embodiment, the apparatus includes an ozone generating unit comprising one or more illumination sources. In another embodiment, the one or more illumination sources are configured to generate an illumination beam with sufficient energy to convert a portion of diatomic oxygen (O2) contained within a gas containment container of a broadband illumination source in a sample characterization system into triatomic oxygen (O3).

[0006] According to one or more embodiments of this disclosure, an apparatus is disclosed. In one embodiment, the apparatus includes a gas containment container for containing a gas. In another embodiment, the gas contains at least triatomic oxygen. In another embodiment, the gas containment container is configured to receive pump illumination from a pump source for sustaining plasma within the gas containment container. In another embodiment, one or more portions of the gas containment container transmit the pump illumination and a portion of broadband light emitted by the plasma.

[0007] According to one or more embodiments of this disclosure, a method is disclosed. In one embodiment, the method includes using one or more illumination beams at a selected location within a gas containment container to convert a portion of diatomic oxygen contained within the gas containment container into triatomic oxygen. In another embodiment, the method includes generating one or more pump beams. In another embodiment, the method includes focusing the one or more pump beams onto the selected location within the gas containment container to ignite a plasma by absorbing the illumination of the one or more pump beams via a portion of the triatomic oxygen. In another embodiment, the method includes collecting a portion of the broadband illumination emitted by the plasma.

[0008] It should be understood that the above general description and the following detailed description are for illustrative purposes only and do not necessarily limit the scope of the claimed invention. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description, serve to explain the principles of the invention. Attached Figure Description

[0009] Those skilled in the art will better understand the many advantages of this disclosure by referring to the accompanying drawings, in which:

[0010] Figure 1A This is a schematic diagram of a laser continuous plasma (LSP) illumination system with illumination-assisted plasma ignition according to one or more embodiments of the present disclosure;

[0011] Figure 1B This is a schematic diagram of a laser continuous plasma (LSP) illumination system with illumination-assisted plasma ignition according to one or more embodiments of the present disclosure;

[0012] Figure 2 It is an implementation of an LSP lighting source (e.g., according to one or more embodiments of this disclosure) Figures 1A to 4 A schematic diagram of the optical characterization system of any LSP illumination system or any combination thereof described herein;

[0013] Figure 3 It is an implementation of an LSP lighting source (e.g., according to one or more embodiments of this disclosure) Figures 1A to 4A schematic diagram of the optical characterization system of any LSP illumination system or any combination thereof described herein; and

[0014] Figure 4 This is a flowchart illustrating a method for implementing a laser continuous plasma illumination system according to one or more embodiments of the present disclosure. Detailed Implementation

[0015] This disclosure has been specifically shown and described with respect to particular embodiments and features. The embodiments set forth herein should be considered illustrative rather than restrictive. It will be readily apparent to those skilled in the art that various changes and modifications in form and detail may be made without departing from the spirit and scope of this disclosure.

[0016] The subject matter of the disclosure will now be described in detail with reference to the accompanying drawings.

[0017] Overall Reference Figures 1A to 4 This disclosure discloses a system and method for generating plasma using illumination-assisted plasma ignition within an oxygen-containing gas containment container, according to one or more embodiments of the present disclosure.

[0018] Embodiments of this disclosure relate to a system and method for generating plasma using illumination-assisted plasma ignition within an oxygen-containing gas containment container. More specifically, embodiments of this disclosure relate to a system and method for igniting plasma contained within a gas containment container using one or more illumination sources and one or more energy sources. Specifically, embodiments of this disclosure relate to a system and method for igniting plasma using one or more illumination sources to convert diatomic oxygen (O2) into triatomic oxygen (O3) and using one or more pump sources as one or more energy sources to ignite the plasma when energy from one or more energy sources is absorbed by the triatomic oxygen (O3) within the gas containment container. Additional embodiments of this disclosure relate to using one or more pump sources to sustain the plasma and using one or more energy sources (e.g., one or more starter lasers) to ignite the plasma.

[0019] As previously described, laser continuous plasma (LSP) lamps are commonly used as broadband light sources in a variety of applications, including wafer inspection and metrology. LSP lamps are filled with rare gases such as argon, krypton, xenon, nitrogen, and the like. However, adding oxygen to the gas mixture inside the lamp is advantageous. Oxygen blocks vacuum ultraviolet (VUV) radiation that can damage the lamp's glass envelope and can also repair defects caused by oxygen depletion on the lamp's inner surfaces. Additionally, oxygen in LSP lamps inhibits the initiation laser breakdown, requiring an initiation laser power almost an order of magnitude higher than that of a pure xenon lamp. However, oxygen cannot be added to lamps with electrodes because it causes severe oxidation during lamp operation.

[0020] U.S. Patent No. 7,435,982, issued October 14, 2008, substantially describes the generation of photo-sustained plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 7,786,455, issued August 31, 2010, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 7,989,786, issued August 2, 2011, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 8,182,127, issued May 22, 2012, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 8,309,943, issued November 13, 2012, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 8,525,138, issued February 9, 2013, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 8,921,814, issued December 30, 2014, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 9,318,311, issued April 19, 2016, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 9,941,655, issued April 10, 2018, also substantially describes the generation of plasma, the entire contents of which are incorporated herein by reference. U.S. Patent No. 10,244,613, issued March 26, 2019, substantially describes electrodeless plasma, the entire contents of which are incorporated herein by reference.

[0021] Figure 1A and 1B This illustration shows a schematic diagram of a laser continuous plasma (LSP) illumination system 100 with illumination-assisted plasma ignition according to one or more embodiments of the present disclosure. The illumination system 100 may generally include one or more pump sources 102, a gas containment container 106, and an ozone generating unit 108.

[0022] In one embodiment, the gas containment container 106 includes a gas volume 105 that can be excited into a plasma state to generate plasma 103. The gas containment container 106 may be further configured to sustain plasma 103 after ignition. The gas volume 105 contained within the gas containment container 106 may contain any gas or gas mixture known in the art suitable for plasma generation. For example, gas volume 105 may contain oxygen (O2). As another example, gas volume 105 may contain at least one of argon (Ar), krypton (Kr), xenon (Xe), nitrogen (N2), or the like, mixed with oxygen (O2). For example, gas volume 105 may contain Ar gas mixed with oxygen. In another example, gas mixture 105 may contain Xe and Ar gases mixed with oxygen. As another example, gas mixture 105 may contain Xe, Kr, N2, and Ar gases mixed with oxygen.

[0023] It should be noted herein that, for the purposes of this disclosure, the terms "LSP lamp" or "plasma lamp" and similar terms may collectively refer to the gas containment container 106 containing the gas volume 105 and the plasma 103. Furthermore, unless otherwise stated herein, the terms "plasma gas containment container" and "gas containment container" are used interchangeably. Additionally, the terms "gas volume," "gas," "gas mixture," and similar terms may refer to the gas 105 contained within the gas containment container 106. The gas containment container 106 may comprise any gas containment container known in the art. For example, a gas containment container may comprise (but is not limited to) at least one of a plasma bulb, a plasma unit, a plasma chamber, or the like.

[0024] It should be noted herein that the gas containment container 106 can be adapted to various shapes for use in the plasma lamp of the lighting system 100. For example, the gas containment container 106 may have a cylindrical shape. As another example, the cylindrical shape of the gas containment container 106 may extend vertically to assist dissipation convection within the plasma lamp. As another example, the gas containment container 106 may have a spherical shape. As an additional example, the gas containment container 106 may have a heart shape (e.g., a heart shape).

[0025] In another embodiment, one or more pump sources 102 are configured to generate one or more pump beams 104 and direct one or more pump beams 104 into a gas containment container 106. The one or more pump sources 102 may comprise any pump source known in the art. For example, one or more pump sources 102 may comprise one or more lasers (e.g., pump lasers). As another example, one or more pump sources 102 may comprise one or more infrared (IR) lasers. As another example, one or more pump sources 102 may comprise one or more continuous wave (CW) IR lasers.

[0026] refer to Figure 1B In another embodiment, system 100 includes one or more energy sources 101 configured to ignite plasma 103 contained within gas 105 in gas containment container 106 by absorbing energy from one or more energy sources 101 via a portion of triatomic oxygen (O3). The one or more energy sources 101 may include any energy source known in the art suitable for igniting plasma 103, including (but not limited to) electric ignition sources (e.g., electrodes, generators, or the like), electromagnetic ignition sources (e.g., Tesla coils), laser sources, or the like. For example, one or more energy sources 101 may be one or more initiating lasers configured to ignite plasma 103. For example, one or more initiating lasers may include pulsed initiating lasers, such that light from one or more pulsed initiating lasers is absorbed by a portion of the triatomic oxygen within gas containment container 106 to ignite plasma 103.

[0027] Refer again Figure 1A In this embodiment, one or more pump sources 102 act as one or more energy sources 101 to ignite the plasma 103. In this embodiment, one or more pump sources 102 are used to ignite the plasma and sustain the plasma 103.

[0028] In another embodiment, system 100 includes one or more illumination optics 114 configured to direct one or more pump beams 104 into a gas 105 contained within a gas containment container 106 at a location near the region where triatomic oxygen is generated (e.g., ozone generating unit 108). The one or more illumination optics 114 may include lenses, mirrors, or the like. For example, one or more illumination optics 114 may include a tuning mirror.

[0029] In another embodiment, the ozone generating unit 108 includes one or more illumination sources 110. The one or more illumination sources 110 may emit light of any selected wavelength or wavelength range, such as (but not limited to) infrared (IR), visible, ultraviolet (UV) radiation, vacuum ultraviolet (VUV) radiation, deep ultraviolet (DUV) radiation, and / or extreme ultraviolet (EUV) radiation. For example, the one or more illumination sources 110 may include one or more ultraviolet (UV) light sources configured to generate one or more UV beams. As another example, the one or more illumination sources 110 may include one or more VUV light sources configured to generate one or more VUV beams. For example, the one or more VUV light sources may include discharge lamps, such as (but not limited to) mercury (Hg) discharge lamps or deuterium lamps. In another example, the one or more VUV light sources may include VUV laser sources. As an additional example, the one or more illumination sources 110 may include microwaves. As another example, the one or more illumination sources 110 may include lasers.

[0030] It should be noted in this document that, for the purposes of this disclosure, the terms “light source” and “light source” are used interchangeably unless otherwise stated herein.

[0031] In another embodiment, one or more illumination sources 110 are configured to generate an illumination beam 115 (e.g., an illumination beam) with sufficient energy to convert a portion of the diatomic oxygen (O2) contained within the plasma gas containment container 106 into triatomic oxygen (O3). It should be noted herein that, for the purposes of this disclosure, the terms “triatomic oxygen,” “ozone,” and “O3” are used interchangeably unless otherwise stated herein. Additionally, for the purposes of this disclosure, the terms “diatomic oxygen” and “O2” are used interchangeably unless otherwise stated herein.

[0032] In another embodiment, the ozone generating unit 108 includes one or more optical elements 112 (e.g., lenses, mirrors, ellipsoids, or the like) positioned along the illumination path and configured to focus a portion of the illumination beam 115 onto a region of the gas containment container 106 near the plasma 103. For example, the one or more optical elements 112 may include lenses, mirrors, or the like.

[0033] In another embodiment, once diatomic oxygen has been converted to triatomic oxygen using an illumination beam 115 from illumination source 110, one or more energy sources 101 are configured to ignite plasma 103 within gas containment container 106. For example, energy from one or more energy sources 101 is absorbed by a portion of the triatomic oxygen within gas containment container 106 to ignite plasma 103. As previously mentioned herein, one or more pump sources 102 may act as one or more energy sources 101 to ignite plasma 103. The applicant notes that gas containment container 106 must contain a sufficient concentration of oxygen, and one or more pump sources 102 must have sufficient power when acting as one or more energy sources 101 so that triatomic oxygen can directly ignite plasma 103. For example, one or more pump sources 102 may include a CW IR laser, and the IR light from the CW IR laser may be absorbed by a portion of the triatomic oxygen within gas containment container 106 to ignite plasma 103. As previously mentioned herein, one or more energy sources 101 may include one or more starter lasers. For example, one or more starter lasers may ignite plasma 103 and one or more pump sources 102 may sustain plasma 103.

[0034] It should be noted that triatomic oxygen exhibits small but appropriate absorption across a wide range of wavelengths, which facilitates the absorption of one or more pump sources, one or more energy sources, and / or one or more starter lasers. For example, one or more pump sources, one or more energy sources, and / or one or more starter lasers can be selected to emit light in the near-IR, visible, or UV ranges. For instance, in the near-IR (NIR) range, triatomic oxygen absorbs approximately 10-1 at 900 nm. -22 cm 2 / molecule. To give another example, at approximately 950 nm, the absorption is between 10... -23 Up to 10 -22 cm 2 / Between molecules. It should be noted that the above examples do not limit the scope of this disclosure, as it should be appreciated herein that various electromagnetic wavelength ranges can be used for its absorption characteristics through triatomic oxygen in various embodiments of this disclosure. Viktor Gorshelev et al. describe the absorption characteristics of triatomic oxygen in “High spectral resolution ozone absorption cross-sections – Part 1: Measurements, data analysis and comparison with previous measurements around 293K” (Atmos.Meas.Tech., 7, 609-624, 2014) (the entire contents of which are incorporated herein by reference).

[0035] Once the plasma 103 is ignited, it can emit broadband (BB) radiation. In another embodiment, system 100 includes one or more collecting optics 116 configured to collect at least a portion of the broadband radiation through the generated plasma 103 and direct the broadband radiation to one or more additional optical elements. System 100 may include any collecting optics known in the art. For example, system 100 may include a dielectric mirror. For example, system 100 may include a cold mirror configured to direct illumination from an elliptical reflector to downstream optics (e.g., filters and light collectors). As another example, one or more collecting optics 116 may include collecting elements. For example, one or more collecting optics 116 may be an elliptical reflector, such as... Figure 1A and 1B As shown in the figure. In one embodiment, the illumination beam 115 from the illumination source 110 may pass through the wall of one or more collecting optics 116.

[0036] One or more additional optical elements may be placed along the illumination path or the collection path. These additional optical elements may be used to focus illumination from one or more pump sources 102 and / or one or more energy sources 101 into the gas volume 105 of the gas containment container 106. Additionally, the additional optical elements may be used to focus broadband light emitted from the gas containment container 106 onto a selected target. In another embodiment, the additional optical elements include filters placed along the illumination path or the collection path to filter illumination before it enters the gas containment container 106 or after it is emitted from the gas containment container 106.

[0037] It should be noted in this article that, as described above and as... Figure 1A and 1B The optical components of system 100 described herein are for illustrative purposes only and should not be construed as limiting. Many equivalent optical configurations are contemplated for use within the context of this invention.

[0038] In another embodiment, the gas containment container 106 is refillable. The gas containment container 106 may include a port assembly (not shown) operatively coupled to a portion of the gas containment container 106. For example, the containment container 106 may include a port assembly mechanically connected to a bottom portion of the containment container 106 and configured to facilitate selective transfer of gas 105 from a gas source to an interior region of the gas containment container 106. Refillable gas bulbs and their various bulb shapes are described in U.S. Patent No. 9,318,311, issued April 19, 2016, the entire contents of which are incorporated herein by reference.

[0039] In one embodiment, the gas containment container 106 includes one or more transmissive portions (e.g., a light bulb, a transmissive element, or a window). The transmissive portions may be formed of any material known in the art that at least partially transmits broadband radiation generated by plasma and / or illumination from the light source 110. For example, one or more transmissive portions (e.g., a light bulb, a transmissive element, or a window) of the gas containment container 106 may be formed of any material known in the art that at least partially transmits EUV, VUV, DUV, UV, NUV, and / or visible light generated within the gas containment container 106. Furthermore, one or more transmissive portions of the gas containment container 106 may be formed of any material known in the art that at least partially transmits IR radiation, visible light, and / or UV light from the light source 110. In another embodiment, one or more transmissive portions of the gas containment container 106 may be formed of any material known in the art that transmits both radiation from the light source 110 (e.g., an IR source) and radiation emitted by the electrode 103 (e.g., EUV, VUV, DUV, UV, NUV, and / or visible light).

[0040] In another embodiment, the plasma lamp containing the gas containment container 106 may be pre-exposed to VUV radiation, allowing triatomic oxygen to be generated before the lamp is installed in system 100. It should be noted that triatomic oxygen can remain in the plasma lamp for an extended period.

[0041] In another embodiment, the plasma lamp may undergo other forms of processing to generate ozone before lamp installation or during the ignition process discussed herein. For example, the lamp may be subjected to microwave discharge, barrier discharge, or the like.

[0042] It should be noted in this paper that alternative lighting geometries may exist, and provide Figure 1A and 1B This is for illustrative purposes only and should not be construed as limiting the scope of this disclosure. For example, the paths of pump beam 104 and / or illumination beam 115 may be altered.

[0043] Although this disclosure has primarily focused on generating triatomic oxygen in a gas container containing diatomic oxygen, it should be noted that in some alternative embodiments, the system 100 of this disclosure can be used to maintain a selected content of triatomic oxygen in a gas container pre-filled with triatomic oxygen. For example, in the case of a gas container pre-filled with triatomic oxygen, the system 100 can be used to replenish the content of triatomic oxygen in the gas container as the triatomic oxygen decays into diatomic oxygen over time.

[0044] Figure 2 This is a schematic diagram of an optical characterization system 200 that implements an LSP illumination source (such as the LSP illumination system 100 or any combination thereof illustrated in any of Figures 1 to 4) according to one or more embodiments of the present disclosure.

[0045] It should be noted herein that system 200 may include any imaging, inspection, metrology, lithography, or other characterization system known in the art. In this regard, system 200 may be configured to perform inspection, optical metrology, lithography, and / or any form of imaging on sample 207. Sample 207 may comprise any sample known in the art, including (but not limited to) wafers, photomasks / masks, and the like. It should be noted that system 200 may be incorporated into one or more of the various embodiments of the LSP illumination system 100 described in this disclosure.

[0046] In one embodiment, sample 207 is positioned on stage assembly 212 to facilitate movement of sample 207. Stage assembly 212 may comprise any stage assembly 212 known in the art, including (but not limited to) XY stages, R-θ stages, and the like. In another embodiment, stage assembly 212 is capable of adjusting the height of sample 207 during inspection or imaging to maintain focus on sample 207.

[0047] In another embodiment, illumination branch 203 is configured to direct illumination from illumination system 100 onto sample 207. Illumination branch 203 may comprise any number and type of optical components known in the art. In one embodiment, illumination branch 203 includes one or more optical elements 202, a beam splitter 204, and an objective lens 206. In this respect, illumination branch 203 may be configured to focus illumination from illumination system 100 onto the surface of sample 207. The one or more optical elements 202 may comprise any optical element or combination of optical elements known in the art, including (but not limited to) one or more mirrors, one or more lenses, one or more polarizers, one or more gratings, one or more filters, one or more beam splitters, and the like.

[0048] In another embodiment, the collecting branch 205 is configured to collect light reflected, scattered, diffracted, and / or emitted from the sample 207. In another embodiment, the collecting branch 205 may guide and / or focus light from the sample 207 onto sensor 216 of detector assembly 214. It should be noted that sensor 216 and detector assembly 214 may comprise any sensor and detector assembly known in the art. For example, sensor 216 may comprise (but is not limited to) charge-coupled device (CCD) detectors, complementary metal-oxide-semiconductor (CMOS) detectors, time-delay integration (TDI) detectors, photomultiplier tubes (PMTs), avalanche photodiodes (APDs), and the like. Furthermore, sensor 216 may comprise (but is not limited to) line sensors or electron-bombarded line sensors.

[0049] In another embodiment, detector assembly 214 is communicatively coupled to controller 218, which includes one or more processors 220 and memory 222. For example, one or more processors 220 may be communicatively coupled to memory 222, wherein one or more processors 220 are configured to execute a set of program instructions stored in memory 222. In one embodiment, one or more processors 220 are configured to analyze the output of detector assembly 214. In one embodiment, the set of program instructions is configured to cause one or more processors 220 to analyze one or more properties of sample 207. In another embodiment, the set of program instructions is configured to cause one or more processors 220 to modify one or more properties of system 200 to maintain focus on sample 207 and / or sensor 216. For example, one or more processors 220 may be configured to adjust objective lens 206 or one or more optical elements 210 to focus illumination from illumination system 100 onto the surface of sample 207. As another example, one or more processors 220 may be configured to adjust the objective lens 206 and / or one or more optical elements 210 to collect illumination from the surface of the sample 207 and focus the collected illumination onto the sensor 216.

[0050] It should be noted that system 200 can be configured with any optical configuration known in the art, including (but not limited to) dark field configuration, bright field orientation and the like.

[0051] It should be noted herein that one or more components of system 200 may be communicatively coupled to various other components of system 200 in any manner known in the art. For example, lighting system 100, detector assembly 214, controller 218, and one or more processors 220 may be communicatively coupled to each other and to other components via wired lines (e.g., copper wires, fiber optic cables, and the like) or wireless connections (e.g., RF coupling, IR coupling, data network communications (e.g., WiFi, WiMax, Bluetooth, and the like)).

[0052] Figure 3 A simplified schematic diagram illustrating an optical characterization system 300 arranged in a reflectance measurement and / or ellipsometric measurement configuration according to one or more embodiments of the present disclosure. It should be noted that, relative to... Figure 2 The various embodiments and components described can be interpreted as extending to Figure 3 The system 300 may contain any type of metrology system known in the relevant field.

[0053] In one embodiment, system 300 includes lighting system 100, lighting branch 316, collection branch 318, detector assembly 328, and controller 218 including one or more processors 220 and memory 222.

[0054] In this embodiment, broadband illumination from illumination system 100 is directed to sample 207 via illumination branch 316. In another embodiment, system 300 collects illumination emitted from the sample via collection branch 318. Illumination branch path 316 may include one or more beam conditioning components 320 adapted to modify and / or adjust the broadband beam. For example, one or more beam conditioning components 320 may include (but are not limited to) one or more polarizers, one or more filters, one or more beam splitters, one or more diffusers, one or more homogenizers, one or more apodizers, one or more beam shapers, or one or more lenses.

[0055] In another embodiment, the illumination branch 316 may use a first focusing element 322 to focus and / or guide the light beam onto the sample 207 mounted on the sample stage 212. In another embodiment, the collection branch 318 may include a second focusing element 326 that collects illumination from the sample 207.

[0056] In another embodiment, detector assembly 328 is configured to capture illumination emitted from sample 207 via collection branch 318. For example, detector assembly 328 may receive illumination reflected or scattered from sample 207 (e.g., via specular reflection, diffuse reflection, and the like). As another example, detector assembly 328 may receive illumination generated by sample 207 (e.g., emission associated with absorption of a light beam, and the like). It should be noted that detector assembly 328 may comprise any sensor and detector assembly known in the art. For example, sensors may include (but are not limited to) CCD detectors, CMOS detectors, TDI detectors, PMTs, APDs, and the like.

[0057] The collecting branch 318 may further include any number of collecting beam adjustment elements 330 that guide and / or modify the illumination collected by the second focusing element 326, which include (but are not limited to) one or more lenses, one or more filters, one or more polarizers or one or more phase plates.

[0058] System 300 can be configured as any type of metrology tool known in the field, such as (but not limited to) a spectroscopic ellipsometer with one or more illumination angles, a spectroscopic ellipsometer for measuring Mueller matrix elements (e.g., using a rotation compensator), a single-wavelength ellipsometer, an angular resolving ellipsometer (e.g., a beam profile ellipsometer), a spectroscopic reflectometer, a single-wavelength reflectometer, an angular resolving reflectometer (e.g., a beam profile reflectometer), an imaging system, a pupil imaging system, a spectroscopic imaging system, or a scatterometer.

[0059] The following provides a description of inspection / measuring tools suitable for implementation in various embodiments of this disclosure: U.S. Patent Application No. 13 / 554,954, entitled “Wafer Inspection System,” filed July 9, 2012; U.S. Patent Application Publication No. 2009 / 0180176, entitled “Split Field Inspection System Using Small Catadioptric Objectives,” published July 16, 2009; U.S. Patent Application Publication No. 2007 / 0002465, entitled “Beam Delivery System for Laser Dark-Field Illumination in a Catadioptric Optical System,” published January 4, 2007; and U.S. Patent Application Publication No. 7, 1999, entitled “Ultra-broadband UV Microscope Imaging System with Wide Range Zoom.” U.S. Patent No. 5,999,310 entitled “Surface Inspection System Using Laser Line Illumination with Two Dimensional Imaging”, published April 28, 2009; U.S. Patent Publication No. 7,525,649 entitled “Surface Inspection System Using Laser Line Illumination with Two Dimensional Imaging”, published May 9, 2013 by Wang et al., entitled “Dynamically Adjustable Semiconductor Metrology System”; and U.S. Patent Publication No. 5,608 entitled “Focused Beam Spectroscopic Ellipsometry Method and System”, published March 4, 1997 by Piwonka-Corle et al.U.S. Patent No. 526 and U.S. Patent No. 6,297,880, issued October 2, 2001, by Rosencwaig et al., entitled "Apparatus for Analyzing Multi-Layer Thin Film Stacks on Semiconductors," the entire contents of each of which are incorporated herein by reference.

[0060] One or more processors 220 of this disclosure may comprise any or more processing elements known in the art. In this regard, one or more processors 220 may comprise any microprocessor-type device configured to execute software algorithms and / or instructions. It should be appreciated that the steps described in this disclosure may be implemented by a single computer system or alternatively by multiple computer systems. Generally, the term "processor" may be broadly defined to encompass any device having one or more processing and / or logic elements that execute program instructions from non-transitory memory media 222. Furthermore, different subsystems of the various systems disclosed may include processors and / or logic elements suitable for implementing at least a portion of the steps described in this disclosure.

[0061] Memory media 222 may comprise any storage medium known in the art suitable for storing program instructions executable by one or more associated processors 220. For example, memory media 222 may comprise non-transitory memory media. For example, memory media 222 may comprise (but is not limited to) read-only memory, random access memory, magnetic or optical memory devices (e.g., magnetic disks), magnetic tape, solid-state drives, and the like. In another embodiment, memory 222 is configured to store one or more results and / or outputs of the various steps described herein. It should be further noted that memory 222 may be housed in a common controller housing with one or more processors 220. In alternative embodiments, memory 222 may be remotely located relative to the physical location of one or more processors 220. For example, one or more processors 220 may access remote memory (e.g., a server) accessible via a network (e.g., the Internet, an intranet, and the like). In this respect, one or more processors 220 of controller 218 may perform any of the various process steps described in this disclosure.

[0062] In some embodiments, the lighting system 100 and systems 200, 300 as described herein may be configured as “standalone tools,” which are interpreted herein as tools not physically coupled to a process tool. In other embodiments, this inspection or measurement system may be coupled to a process tool (not shown) via a transmission medium (which may include wired and / or wireless portions). The process tool may include any process tool known in the art, such as photolithography tools, etching tools, deposition tools, polishing tools, electroplating tools, cleaning tools, or ion implantation tools. The results of inspections or measurements performed by the system described herein can be used to modify the parameters of the process or process tool using feedback control techniques, feedforward control techniques, and / or in-situ control techniques. The parameters of the process or process tool can be changed manually or automatically.

[0063] Embodiments of lighting system 100 and systems 200, 300 may be further configured as described herein. Additionally, lighting system 100 and systems 200, 300 may be configured to perform any other steps of any of the method embodiments described herein (e.g., method 400).

[0064] Figure 4 This is a flowchart illustrating a method 400 for igniting an oxygen-containing LSP lamp according to one or more embodiments of the present disclosure. It should be noted herein that the steps of method 400 may be implemented entirely or partially by system 100 and / or system 200. However, it should be further appreciated that method 400 is not limited to system 100 and / or system 200, as all or part of the steps of method 400 may be implemented by additional or alternative system-level embodiments.

[0065] In step 402, one or more illumination beams are used at selected locations within the containment container 106 to convert a portion of the diatomic oxygen (O2) contained within the plasma gas containment container 106 into triatomic oxygen (O3). In one embodiment, one or more illumination sources 110 (e.g., Hg discharge lamps) are configured to convert a portion of the diatomic oxygen within the containment container 106 into triatomic oxygen. One or more optical elements 112 of the ozone generating unit 108 may be configured to focus a portion of the light onto a region of the gas containment container 106 near the plasma 103.

[0066] In step 404, one or more pump beams 104 are generated. In one embodiment, one or more pump sources 102 are configured to generate one or more pump beams 104.

[0067] In step 406, one or more pump beams 104 are focused onto selected locations within the containment container 106 to ignite plasma 103 by illumination through which a portion of the pump beams 104 are absorbed by triatomic oxygen (O3). In one embodiment, one or more illumination optics 114 are configured to direct one or more pump beams 104 into gas 105 contained within the gas containment container 106 at the selected location where triatomic oxygen is generated.

[0068] In step 408, a portion of the broadband illumination emitted by plasma 103 is collected. In one embodiment, one or more collecting optics 116 are configured to collect at least a portion of the broadband radiation emitted by the generated plasma 103 and direct the broadband radiation to one or more additional optics.

[0069] It should be noted that method 400 can reduce the threshold for starting laser operation (e.g., igniting the laser), which allows for the use of lower power starting lasers in oxygen-containing LSP lamps.

[0070] Those skilled in the art will recognize that the components (e.g., operations), apparatuses, objects, and accompanying discussions described herein are examples used to clarify concepts and to allow for consideration of various configuration modifications. Therefore, as used herein, the specific paradigms illustrated and the accompanying discussions are intended to represent their more general categories. In general, the use of any particular paradigm is intended to represent its category, and the omission of specific components (e.g., operations), apparatuses, and objects should not be considered a limitation.

[0071] Those skilled in the art will understand that various vehicles (e.g., hardware, software, and / or firmware) exist that can implement the processes and / or systems and / or other technologies described herein, and the preferred vehicle will vary depending on the context in which the processes and / or systems and / or other technologies are deployed. For example, if the implementer determines that speed and accuracy are paramount, then the implementer may choose a primary hardware / / software vehicle; alternatively, if flexibility is paramount, then the implementer may choose a primary software implementation; or alternatively, the implementer may choose a combination of hardware, software, and / or firmware. Thus, several possible vehicles exist that can implement the processes and / or devices and / or other technologies described herein, and no vehicle is inherently superior to another, because the use of any vehicle depends on the context in which the vehicle will be deployed and the implementer's specific concerns (e.g., speed, flexibility, or predictability) (any of which can vary).

[0072] The invention is presented in the context of enabling those skilled in the art to make and use the invention in particular applications and their requirements. As used herein, directional terms (e.g., “top,” “bottom,” “above,” “below,” “up,” “down,” “under,” and “downward”) are intended to provide relative positions for descriptive purposes and are not intended to specify an absolute frame of reference. Those skilled in the art will appreciate various modifications to the described embodiments, and that the general principles defined herein may be applied to other embodiments. Therefore, the invention is not intended to be limited to the specific embodiments shown and described, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

[0073] Regarding the use of generally plural and / or singular terms in this document, those skilled in the art may convert plural to singular and / or singular to plural as required by the text and / or application. Various singular / plural arrangements are not explicitly described herein for clarity.

[0074] All methods described herein may involve storing the results of one or more steps of the method embodiments in memory. The results may include any of the results described herein and may be stored in any manner known in the art. The memory may include any memory described herein or any other suitable storage medium known in the art. After storing the results, the results may be accessed in memory and used by any of the methods or system embodiments described herein, formatted for display to a user, used by another software module, method, or system, etc. Furthermore, the results may be stored "permanently," "semi-permanently," "temporarily," or for a period of time. For example, the memory may be random access memory (RAM), and the results may not necessarily be stored in memory indefinitely.

[0075] Upon further careful consideration, each of the embodiments of the above methods may include any other steps of any other method described herein. Furthermore, each of the embodiments of the above methods may be performed by any of the systems described herein.

[0076] The topics described herein sometimes illustrate different components housed within or connected to other components. It should be understood that the architectures depicted are merely illustrative, and many other architectures can in fact be implemented to achieve the same functionality. Conceptually, any arrangement of components that achieve the same functionality is effectively “associated” to achieve the desired functionality. Therefore, any two components combined in this document to achieve a particular functionality can be considered “associated” with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two such associated components can also be considered “connected” or “coupled” to each other to achieve the desired functionality, and any two components that can be suchly associated can also be considered “coupleable” to each other to achieve the desired functionality. Specific examples of coupleability include (but are not limited to) physically mating and / or physically interacting components and / or wirelessly interacting and / or logically interacting components.

[0077] Furthermore, it should be understood that the invention is defined by the appended claims. Those skilled in the art will understand that, generally, the terminology used herein and, in particular, in the appended claims (e.g., the body of the appended claims) is intended to be “open” terminology (e.g., the term “comprising” should be interpreted as “comprising (but not limited to)”, the term “having” should be interpreted as “having at least”, the term “includes” should be interpreted as “comprising (but not limited to)”, etc.). Those skilled in the art will further understand that if a specific number of claims is desired, this intention will be explicitly stated in the claims, and if no such statement is made, then this intention does not exist. For example, to aid understanding, the appended claims may contain the use of the introductory phrases “at least one” and “one or more” to introduce the claims. However, the use of such phrases should not be construed as implying that the introduction of a claim statement by the indefinite article “a” or “an” limits any particular claim containing such an introductory claim statement to an invention containing only one such statement, even if the same claim contains the introductory phrase “a or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and / or “an” should generally be interpreted as meaning “at least one” or “a or more”); the same applies to the use of definite articles used to introduce claim statements. Furthermore, even if a specific number of claim statements is explicitly stated, those skilled in the art will recognize that such a statement should generally be interpreted as meaning at least a number of statements (e.g., a bare statement of “two statements” without other modifiers generally means at least two statements or two or more statements). Furthermore, in examples where a convention similar to "at least one of A, B, and C and similar to thereof" is used, this construction is generally intended to be understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" would include (but is not limited to) systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). In examples where a convention similar to "at least one of A, B, or C and similar to thereof" is used, this construction is generally intended to be understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" would include (but is not limited to) systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). Those skilled in the art will further understand that virtually any disjunctive terms and / or phrases presenting two or more alternatives, whether in the detailed description, claims, or figures, should be understood to consider the possibility of including one, either, or both of the terms. For example, the phrase "A or B" will be understood to include the possibility of including "A" or "B" or "A and B".

[0078] It is believed that this disclosure and its many accompanying advantages will be understood from the foregoing description, and it should be understood that various changes can be made to the form, construction, and arrangement of the components without departing from the disclosed subject matter or sacrificing all its material advantages. The forms described are for illustrative purposes only, and the appended claims are intended to cover and encompass such changes. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. A laser-based continuous plasma illumination system with illumination-assisted plasma ignition, comprising: A gas containment container configured to contain gas; One or more pump sources configured to generate one or more pump beams for sustaining plasma within the gas containment container; and An ozone generating unit comprising one or more illumination sources configured to generate an illumination beam with sufficient energy to convert a portion of the diatomic oxygen (O2) contained within the gas containing container into triatomic oxygen (O3). One or more energy sources are configured to ignite a plasma contained within a gas within a gas containment container by absorbing energy from the one or more energy sources through a portion of the triatomic oxygen, wherein the plasma emits broadband radiation, and The plasma described therein is electrodeless.

2. The laser continuous plasma illumination system of claim 1, wherein the one or more illumination sources of the ozone generating unit include one or more ultraviolet light sources configured to generate one or more ultraviolet beams.

3. The laser continuous plasma illumination system according to claim 2, wherein the one or more ultraviolet light sources comprise: One or more vacuum ultraviolet light sources configured to generate one or more vacuum ultraviolet beams.

4. The laser continuous plasma illumination system according to claim 3, wherein the one or more vacuum ultraviolet light sources comprise: Discharge lamp.

5. The laser continuous plasma illumination system according to claim 4, wherein the discharge lamp comprises: Mercury discharge lamp or deuterium lamp.

6. The laser continuous plasma illumination system according to claim 1, wherein the one or more illumination sources of the ozone generating unit comprise: microwave.

7. The laser continuous plasma illumination system according to claim 1, wherein the one or more illumination sources of the ozone generating unit comprise: One or more lasers.

8. The laser continuous plasma illumination system according to claim 3, further comprising: One or more optical elements configured to focus a portion of the vacuum ultraviolet light onto a region of the gas containment container near the plasma.

9. The laser-based continuous plasma illumination system according to claim 1, wherein the one or more pump sources comprise: One or more lasers.

10. The laser-based continuous plasma illumination system according to claim 9, wherein the one or more pump sources comprise: One or more infrared lasers.

11. The laser-based continuous plasma illumination system according to claim 10, wherein the one or more pump sources comprise: One or more continuous wave (CW) infrared lasers, wherein infrared light from the one or more CW lasers is absorbed by the portion of the triatomic oxygen within the gas containment container to ignite the plasma.

12. The laser continuous plasma illumination system according to claim 1, wherein the one or more energy sources comprise: At least one of an electric ignition source, an electromagnetic ignition source, or a laser ignition source.

13. The laser continuous plasma illumination system according to claim 12, wherein the laser ignition source comprises one or more starting lasers.

14. The laser-based continuous plasma illumination system according to claim 13, wherein the one or more starting lasers comprise: One or more pulsed lasers, wherein light from the one or more pulsed lasers is absorbed by the portion of the triatomic oxygen within the gas containment container to ignite the plasma.

15. The laser-based continuous plasma illumination system of claim 1, wherein the one or more pump sources act as the one or more energy sources to ignite the plasma contained in the gas within the gas containment container.

16. The laser continuous plasma illumination system according to claim 1, further comprising: One or more illumination optics configured to direct the one or more pump beams into the gas contained within the gas containment container at a location close to the region where triatomic oxygen is generated.

17. The laser continuous plasma illumination system according to claim 1, further comprising: One or more collecting optics configured to collect at least a portion of the broadband radiation emitted by the generated plasma and to direct the broadband radiation to one or more additional optics.

18. The laser continuous plasma illumination system according to claim 1, wherein the gas comprises: Diatomic oxygen.

19. The laser continuous plasma illumination system according to claim 1, wherein the gas comprises: A gaseous mixture containing diatomic oxygen.

20. The laser continuous plasma illumination system according to claim 19, wherein the gas mixture comprises: At least one of argon, krypton, xenon, or triatomic oxygen mixed with diatomic oxygen.

21. The laser continuous plasma illumination system according to claim 1, wherein the gas containment container comprises: At least one of a plasma bulb, a plasma unit, or a plasma chamber.

22. A laser-based continuous plasma lighting device with illumination-assisted plasma ignition, comprising: A gas containment container for containing a gas, said gas containing at least some triatomic oxygen, said gas containment container being configured to receive pump illumination from a pump source for sustaining an electrodeless plasma within said gas containment container, said gas containment container having one or more portions therein transmitting the pump illumination and a portion of broadband light emitted by said plasma; and An ozone generating unit comprising one or more illumination sources configured to generate an illumination beam with sufficient energy to convert a portion of the diatomic oxygen (O2) contained within the gas containing container into triatomic oxygen (O3).

23. A method for implementing a laser-based continuous plasma illumination system, comprising: Using one or more illumination beams at a selected location within the gas containment container, a portion of the diatomic oxygen contained within the gas containment container is converted into triatomic oxygen. Generate one or more pump beams; Focusing the one or more pump beams onto the selected location within the gas containment container to ignite the plasma via illumination through which a portion of the one or more pump beams absorbs the triatomic oxygen; and A portion of the broadband illumination emitted by the plasma is collected, and The plasma described therein is electrodeless.

24. The method of claim 23, wherein using one or more illumination beams at a selected location within the gas containment container to convert a portion of the diatomic oxygen contained within the gas containment container into triatomic oxygen comprises: One or more vacuum ultraviolet beams are used at selected locations within the gas containment container to convert a portion of the diatomic oxygen contained within the gas containment container into triatomic oxygen.

25. The method of claim 23, wherein generating one or more pump beams comprises: It generates one or more infrared pump beams.

26. The method of claim 23, further comprising: At least one of the tests or measurements is performed using the collected broadband lighting.

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