X-ray analysis system with laser-driven source

Abstract

The present invention provides a method and system for incorporating an X-ray source into an X-ray system. [Solution] A system (10, 11) for X-ray analysis includes an X-ray enclosure (55) and a window assembly (66a, 66b, 66c, 66d). The X-ray enclosure includes (a) an XRS configured to emit one or more X-ray beams (12) in response to a laser beam (33) striking the surface of an X-ray source (XRS) (44), and (b) configured to prevent the emission of one or more X-ray beams from leaving the X-ray enclosure, and the X-ray enclosure has a window (65) configured to allow the laser beam to pass into the X-ray enclosure. The window assembly is coupled to the window and configured to (i) bend the laser beam to pass into the X-ray enclosure, and (ii) prevent one or more X-ray beams (12, 16, 20) from leaving the X-ray enclosure.

Description

[Technical Field]

[0001] [Cross-reference with related applications] This application claims the interests of U.S. Provisional Patent Application No. 63 / 493,020, filed on 30 March 2023, the disclosures of which are incorporated herein by reference.

[0002] The present invention relates to X-ray analysis in general, and more specifically to a method and system for incorporating an X-ray source into an X-ray system. [Background technology]

[0003] X-ray technology is used in the research, development, optimization, and production of various types of materials and structures across a wide range of industries and products.

[0004] Different applications of X-rays require different characteristics of the X-ray beam, including, but are not limited to, energy, power, spot size, flux, uniformity across the spot, and brightness (also referred to herein as luminance). X-ray beams are optimized to meet the specific application requirements based on trade-offs and optimizations of these characteristics.

[0005] Some technologies utilize liquid metal-based X-ray sources. For example, U.S. Patent No. 7,929,667 describes an X-ray measurement tool having a liquid metal-based X-ray source to enhance the brightness of X-rays emitted from the source.

[0006] U.S. Patent Application Publication No. 2018 / 0206319 describes a laser-generated plasma X-ray system that includes a liquid metal flow system enclosed in a low-pressure chamber. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 7,929,667 [Patent Document 2] U.S. Patent Application Publication No. 2018 / 0206319 [Overview of the Initiative]

[0008] Embodiments of the present invention described herein provide an X-ray analysis system comprising an X-ray enclosure and a window assembly. The X-ray enclosure includes (a) an XRS configured to emit one or more X-ray beams in response to a laser beam striking the surface of the XRS, and (b) a window configured to prevent the emission of one or more X-ray beams from leaving the X-ray enclosure, wherein the X-ray enclosure has a window configured to allow the laser beam to pass into the X-ray enclosure. The window assembly is coupled to the window and configured to (i) bend the laser beam to pass into the X-ray enclosure, and (ii) prevent the emission of one or more X-ray beams from leaving the X-ray enclosure.

[0009] In some embodiments, the window assembly includes (i) an X-ray shielding labyrinth and (ii) one or more mirrors positioned within the labyrinth and configured to bend the laser beam once or twice or more. In other embodiments, the window assembly includes (i) an X-ray shielding labyrinth and (ii) one or more prisms positioned within the labyrinth and configured to bend the laser beam once or twice or more. In yet another embodiment, the X-ray enclosure is 10 -3 It is configured to operate at a higher pressure than Torr.

[0010] In some embodiments, the X-ray enclosure is configured to operate at atmospheric pressure. In other embodiments, the XRS includes a liquid metal, and one or more X-ray beams are emitted in response to a laser beam striking the liquid metal. In yet another embodiment, the XRS includes a target selected from a list of targets comprising at least one of (i) a continuous solid metal wire, (ii) a strip of solid metal, (iii) a droplet of liquid metal, (iv) a jet of continuous liquid metal, (v) a rotating drum coated with liquid metal, and (vi) a rotating disk coated with liquid metal, and one or more X-ray beams are emitted in response to a laser beam striking the target.

[0011] In some embodiments, the laser beam is generated by a laser light source located outside the X-ray enclosure. In other embodiments, one or more X-ray beams consist of X-ray beam pulses. In yet another embodiment, the X-ray beam pulses have a frequency of 1 kHz to 100 MHz.

[0012] According to embodiments of the present invention, a method is provided which includes receiving a laser beam directed toward a window of an X-ray enclosure, the laser beam being bent within a window assembly coupled to the window, and the laser beam being directed through the window toward an X-ray source (XRS) located within the X-ray enclosure. By impacting the XRS with the laser beam, one or more X-ray beams are emitted, and the emission of one or more X-ray beams is prevented from leaving the X-ray enclosure.

[0013] In some embodiments, receiving a laser beam includes generating a laser beam in a laser source located outside the X-ray enclosure and directing the laser beam toward a window, and emitting one or more X-ray beams includes emitting one or more pulses of X-ray beams.

[0014] According to embodiments of the present invention, a method for manufacturing an X-ray analysis system is further provided, the method comprising arranging within an X-ray enclosure having a window: (i) an X-ray source (XRS) for generating one or more X-ray beams; (ii) a detector assembly for generating a signal in response to the one or more X-ray beams colliding with a sample and then with a detector assembly; and (iii) an X-ray optical system for directing one or more X-ray beams (a) from the XRS towards the sample and (b) from the sample towards the detector assembly. Outside the X-ray enclosure, a laser light source is arranged for directing a laser beam through a window towards the XRS. The window of the X-ray enclosure is coupled with a window assembly having (i) an X-ray blocking labyrinth and (ii) one or more optical elements arranged within the X-ray blocking labyrinth for (a) bending the laser beam once or twice or more within the labyrinth and (b) directing the laser beam through the window towards the XRS to generate one or more X-ray beams.

[0015] In some embodiments, one or more optical elements for bending and directing the laser beam include at least one of (i) a mirror for reflecting the laser beam and (ii) a prism for refracting the laser beam. In other embodiments, the X-ray enclosure is opaque to one or more X-ray beams, and a window allows the laser beam to pass through the X-ray enclosure. In yet another embodiment, arranging the XRS includes arranging an XRS having a liquid metal target for generating pulses of one or more X-ray beams in response to the laser beams colliding with the liquid metal of the XRS.

[0016] The present invention will be understood more fully by interpreting the following detailed description of embodiments of the invention together with the drawings. [Brief explanation of the drawing]

[0017] [Figure 1]A block diagram schematically showing a reflection geometry-based X-ray analysis system according to an embodiment of the present invention. [Figure 2] A block diagram schematically showing a transmission geometry-based X-ray analysis system according to another embodiment of the present invention. [Figure 3] A cross-sectional view of a window assembly that passes a laser beam into the X-ray enclosure of FIGS. 1 and 2 according to some embodiments of the present invention. [Figure 4] A cross-sectional view of a window assembly that passes a laser beam into the X-ray enclosure of FIGS. 1 and 2 according to some embodiments of the present invention. [Figure 5] A cross-sectional view of a window assembly that passes a laser beam into the X-ray enclosure of FIGS. 1 and 2 according to some embodiments of the present invention. [Figure 6] A cross-sectional view of a window assembly that passes a laser beam into the X-ray enclosure of FIGS. 1 and 2 according to some embodiments of the present invention. [Figure 7] A flowchart schematically showing a method of operating the X-ray analysis system of FIGS. 1 and 2 using at least one of the window assemblies of FIGS. 3 to 6 according to an embodiment of the present invention. [Figure 8] A flowchart schematically showing a method of manufacturing the X-ray analysis system of FIGS. 1 and 2 according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0018] Overview Embodiments of the present invention described herein provide an X-ray analysis system comprising: (i) an X-ray source assembly (XRS) having a structure and characteristics described later, configured to generate an X-ray beam; (ii) a laser assembly configured to direct a laser beam to the XRS to generate an X-ray beam; (iii) a source optical system configured to direct the X-ray beam to a sample of interest; (iv) a detector assembly including one or more detectors configured to detect an X-ray beam emitted from a sample; and (v) detector optics configured to direct an X-ray beam from a sample to the detector assembly. The X-ray analysis system may have (i) a reflection geometry in which the incident X-ray beam is reflected from the sample and subsequently directed to the detector assembly by the detector optical system, or (ii) a transmission geometry in which the incident X-ray beam is transmitted (e.g., scattered) through the sample and subsequently directed to the detector assembly by the detector optical system.

[0019] In some embodiments, the X-ray beam generated by the XRS includes a pulsed X-ray beam. In this example, the pulse rate of the generated X-ray beam has a frequency range of about 1 kHz to several (e.g., about 100) MHz. Furthermore, the pulsed nature of the generated X-ray beam has instantaneous power that can be substantially greater than the average power of a continuous (i.e., unpulsed) X-ray beam generated in an electron beam-driven X-ray source.

[0020] In some embodiments, the X-ray analysis system includes (a) an XRS configured to emit an X-ray beam in response to a laser beam striking the surface of the XRS, and (b) an X-ray safety enclosure, also referred to herein as an X-ray enclosure, configured to prevent the emission of the X-ray beam from leaving the X-ray enclosure. The X-ray enclosure has a window configured to allow a laser beam to pass through into the X-ray enclosure. In this example, to provide X-ray safety to the user, the X-ray enclosure is further configured to house a source optical system, a detector optical system, a sample, and a detector assembly.

[0021] In some embodiments, the laser assembly includes a laser light source configured to generate the laser beam described above. However, in this example configuration, at least the laser light source is located outside the X-ray enclosure.

[0022] In some embodiments, the X-ray analysis system further includes a window assembly coupled to the window of the X-ray enclosure (e.g., assembled in or manufactured together with the window assembly). The window assembly is configured to (i) bend the laser beam through to the X-ray enclosure and (ii) prevent the emission of one or more X-ray beams from leaving the X-ray enclosure.

[0023] In some embodiments, the window assembly includes an X-ray blocking labyrinth. In the context of this disclosure and in the claims, the term “labyrinth” means the configuration of a wall and / or compartment that includes one or more optical elements, such as one or more laser reflectors and / or refractive elements, which are formed of an X-ray-impermeable (or partially impermeable) material, and which are not limited to one or more of the elements described below. The labyrinth is configured to absorb any X-ray radiation passing through the window of the X-ray enclosure while not obstructing the path of the laser beam.

[0024] In some embodiments, the reflecting and / or refractive elements may include one or more mirrors and / or one or more prisms arranged within a labyrinth, each configured to bend the laser beam once or twice or more.

[0025] In some embodiments, XRS is, for example, about 10 -5 torr~10 -13 Torr pressure (for example, about 10 -7It is configured to operate in a high vacuum or ultra-high vacuum (at a pressure lower than Torr). In this example, the XRS includes a liquid metal target that improves the brightness and other properties of the X-ray beam. As described above, the X-ray beam is emitted from the XRS in response to the laser beam colliding with the liquid metal target. Some configurations of the liquid metal target and the XRS, as well as further components and assemblies of the X-ray system (e.g., the optical system and detectors and the moving stage described above), are described in detail in Figures 1 to 6 below.

[0026] In some embodiments, the X-ray enclosure is 10 -3 While configured to operate at a pressure higher than Torr, in other embodiments the X-ray enclosure is configured to operate at atmospheric pressure, as detailed below.

[0027] The disclosed technology enhances the functionality and safety of X-ray systems. For example, the disclosed technology improves the integration of liquid metal-based X-ray sources into X-ray analysis systems operating in various facilities such as research facilities, development facilities, and high-volume production (HMV) facilities. Based on the disclosed technology, the laser assembly can be located in different rooms (such as sub-fab areas in semiconductor manufacturing facilities) or in racks outside the X-ray enclosure.

[0028] System Description Figure 1 is a schematic block diagram showing a reflection geometry-based X-ray analysis system 10 according to an embodiment of the present invention. For simplicity, in this specification, the reflection geometry-based X-ray analysis system 10 is also referred to as system 10.

[0029] In some embodiments, the system 10 includes a laser source 22 mounted within a laser assembly (not shown) which has further components such as control hardware and laser drive circuits for the laser assembly, laser optics and housing. As will be described in detail below, the term "laser source" in the context of this disclosure and in the claims means a laser-driven X-ray source. The laser source 22 is configured to emit one or more laser beams, referred to herein as beam 33, which are directed by the laser optics through a window assembly 66 into an X-ray safety enclosure 55. In some embodiments, the laser beams may have a preferred wavelength between ultraviolet and infrared, for example, about 100 nm to at least 2000 nm. Embodiments and configurations of the window assembly 66 are described in detail below in Figures 3, 4, 5 and 6, and the X-ray safety enclosure 55 is described here.

[0030] In some embodiments, the system 10 includes, in addition to the laser light source 22, (i) one or more X-ray source assemblies (XRS) 44 configured to generate pulsed X-ray beams 12 as described later; (ii) a source optical system 14 configured to receive the X-ray beams 12 and focus them as incident beams 16 directed to collide with a sample 18 mounted on a stage 19 (the characteristics of the sample 18 and stage 19 will be described in detail below); (iii) a beam monitor 17 positioned along the optical path of the incident beams 16 and configured to monitor the characteristics of the beams 16 before they collide with the surface of the sample 18; and (iv) one or more detectors (e.g., two-dimensional photon counting detectors or charge integrating detectors) configured to generate signals in response to detecting X-ray beams 20 scattered from the sample 18. (v) a detector assembly 26 including detectors, (v) a detector optical system 24 configured to direct an X-ray beam 20 from a sample 18 towards the detector assembly 26, and (vi) a processor 50 configured to receive signals from the detector assembly 26 and (b) control the components and assemblies of the system 10 as described in detail below.

[0031] In this configuration, the processor 50 includes any preferred type of central processing unit (CPU), or graphical processing unit (GPU), or tensor processing unit (TPU), or any other preferred type of application-specific integrated circuit (ASIC), which is implemented in a general-purpose computer and programmed in software form to perform the functions described herein. The software can be downloaded to the computer in electronic form, for example, via a network, or, in addition to or instead of this, can be provided and / or stored in a non-temporary tangible medium such as magnetic, optical, or electronic memory.

[0032] In some embodiments, the X-ray safety enclosure 55, also referred to herein (for brevity) as the X-ray enclosure (55) or enclosure 55 in this disclosure and claims, is configured to include all the above-mentioned components and assemblies other than the laser light source 22. Furthermore, the X-ray safety enclosure 55 is configured to prevent the emission of X-ray beams (e.g., beams 12, 16, and 20) from leaving the X-ray enclosure 55 for the safety of the user of the system 10.

[0033] In some embodiments, the X-ray safety enclosure 55 is at atmospheric pressure, or about 10°C. -3 It is configured to operate at any low vacuum level, such as a pressure higher than torr. In one embodiment, the X-ray enclosure 55 has a window 65 configured to allow a laser beam 33 to pass through the X-ray enclosure 55 and to maintain a target pressure within the X-ray enclosure 55. Thus, if the X-ray analysis application requires near-atmospheric pressure (e.g., the low vacuum levels described above), the window 65 seals the X-ray enclosure 55 to achieve the required pressure (e.g., about 10°C). -3 It is configured to maintain a vacuum level (higher than Torr but lower than atmospheric pressure).

[0034] In some embodiments, one or more XRS44s are mounted on a stage 21 having the features described below. Each XRS44 has an X-ray source head including a liquid metal target. In some embodiments, the XRS44 is configured to generate one or more X-ray beams, referred to herein as beam 12, in response to the beam 33 colliding with the liquid metal target.

[0035] In some embodiments, the X-ray beam 12 includes a pulsed X-ray beam. In this example, the pulse rate of the X-ray beam 12 has a frequency range of about 1 kHz to several (e.g., about 100) MHz. Furthermore, the pulsed nature of the X-ray beam 12 has instantaneous power that can be substantially greater than the average power of a continuous X-ray beam generated in an electron beam-driven X-ray source that directs an electron beam to collide with a solid target.

[0036] In some embodiments, XRS44 is configured to operate in an ultra-high vacuum at a pressure of, for example, about 10 -5 torr to 10 -13 torr. In some embodiments, without limitation, a suitable configuration is selected from a list of configurations such as (i) a target of a continuous jet of liquid metal, (ii) a rotating drum liquid metal target, and (iii) a rotating disk liquid metal target, etc., to generate a liquid metal target within the X-ray source head.

[0037] In some embodiments, XRS44 having a liquid metal jet target includes a liquid metal reservoir, a pump, and a nozzle. During operation, the pump draws liquid metal from the reservoir into a nozzle configured to eject droplets of liquid metal towards the reservoir. In this configuration, the laser beam 33 is directed from the laser light source 22 and collides with the liquid metal droplets or a continuously flowing liquid metal target (jet) to generate the beam 12. Note that the jet of liquid metal can include separated droplets of liquid metal or a continuous jet. The configuration of the liquid (e.g., separated droplets or continuous jet) can affect the characteristics (e.g., frequency) of the X-rays generated in response to the laser beam colliding with the liquid metal.

[0038] In some embodiments, XRS44 having a rotating drum liquid metal target includes a liquid metal reservoir and a rotating drum partially submerged in the liquid metal. During operation, the outer surface of the drum is submerged and wetted with the liquid metal, and the liquid metal remaining on the surface while rotating is drawn out from the reservoir and faces the beam 33. In this configuration, the laser beam 33 is directed from the laser light source 22 and collides with the liquid metal wetting the drum surface to generate the beam 12.

[0039] In some embodiments, the XRS44 having a rotating disk liquid metal target includes a disk comprising one or more compartments, each containing liquid metal and having an opening. During operation, as the disk rotates, centrifugal force is applied to the liquid metal. In response to this centrifugal force, liquid metal accumulates in the corners of each compartment facing the laser beam 33. In this configuration, the laser beam 33 is directed from the laser source 22 and strikes the liquid metal in the corners, generating a beam 12 that is emitted through the respective openings.

[0040] The liquid metal jet target, rotating drum liquid metal target, and rotating disk liquid metal target are examples of liquid metal target implementations. In other embodiments, the XRS44 can be implemented using any other configuration suitable for generating X-rays 12 having the characteristics (e.g., brightness, flux, energy) required for each X-ray analysis application. In this example, the energy of the X-ray beam can be in the range between soft and hard X-rays, for example, about 0.2 keV to several tens of keV. These energies are typically higher than those used in extreme EUV applications, which are typically lower than about 150 eV.

[0041] In some embodiments, the stage 21 is configured to move the XRS44 relative to the beam 33 to improve the generation of the beam 12 as described above. In one implementation, the stage 21 is configured to move at least along the Z axis of the XYZ coordinate system, and the system 10 includes at least two XRS44 mounted side by side on the stage 21. In this implementation, at least two of the XRS44 may have different material compositions that give different properties to the X-ray beam 12 emitted from each XRS44. The material for the liquid metal target can be selected from a list of metals having a melting point lower than about 300°C, such as gallium (about 30°C), indium (about 156°C), tin (about 232°C), thallium (about 300°C), bismuth (about 270°C), and any preferred combination thereof. In addition to or instead of this, at least two of the XRS44 may have any other differences that are different from each other that can give different properties to the X-ray beam 12 emitted from them.

[0042] In this implementation, the system 10 may include first and second XRS44s (not shown) configured to generate X-ray beams 12 having first and second characteristics, respectively. In some embodiments, the processor 50 is configured to control the stage 21 to move, for example, along the Z-axis, so that (i) the beam 33 collides with a liquid metal target of the first XRS44 in a first X-ray analysis application, and (ii) the beam 33 collides with a liquid metal target of the second XRS44 in a second X-ray analysis application, based on the requirements of the X-ray analysis application.

[0043] In another implementation, system 10 may include a single XRS44 having a single X-ray source head and a single laser assembly having a single laser source 22. In this implementation, the XRS44 is mounted on a stage 31 which is a rotating and / or translational stage, and a laser beam 33 is projected into a multi-joint arm (not shown) having one or more elbows. In this configuration, the XRS44 can move while maintaining a constant interaction point of the laser beam 33 on a liquid metal target. For example, by using two different sets of mirrors (e.g., rotating around the Y axis of the XYZ coordinate system), two different positions of the XRS44 are possible, and thus two different laser beams 33 can be generated.

[0044] In addition to or instead of the above, in some embodiments, the system 10 may also include two or more laser sources 22, such as a first and a second, configured to generate first and second X-ray beams 33, respectively, intended to be sequentially directed to collide with a single XRS44. In this implementation, the processor 50 is configured to (i) increase the efficiency of the XRS44 by controlling the first laser source 22 to excite the XRS44 by directing the first beam 33 toward the XRS44, and (ii) control the second laser source 22 to subsequently direct the second beam 33 toward the XRS44 to generate an X-ray beam 12 having the desired characteristics (e.g., higher brightness compared to a beam 12 generated without the first laser beam 33 colliding with the XRS44).

[0045] In other embodiments, the processor 50 is configured to control a single XRS44 to direct the first beam 33 and the subsequent second beam 33 in order to obtain the excitation effect of the XRS44 as described in detail above.

[0046] In some embodiments, the stage 19 includes an electric stage such as an XYZχωφ stage or XYZ stage to which the chuck 15 is attached, where χωφ is the axis of rotation centered on the x, y, and z directions. Additionally, one or more detectors of the detector assembly 26 may be mounted on a rotating stage typically called a 2θ axis. The stage 19 is controlled by the processor 50 to move the sample 18 in the XYZ coordinate system described above. Specifically, the processor 50 is configured to control the stage 19 to move (i) along the X and Y axes to perform X-ray analysis at a predetermined measurement site on the sample 18, and (ii) along the Z axis to focus the incident beam 16 onto the outer surface of the sample 18.

[0047] In some embodiments, the stage 21 may include a rotating stage configured to rotate the XRS44 around the Y axis. In such embodiments, the processor 50 is configured to (i) control the stage 21 to rotate around the Y axis and simultaneously (ii) control the stage 19 to move along the Z axis in order to maintain focus of the beam 16 on the surface of the sample 18.

[0048] In some embodiments, the number and type of detectors in the detector assembly 26 depend on the technology used. Furthermore, as described above, the XRS44 is configured to generate a pulsed beam 12. In this example, the pulse rate of the beam 12 has a frequency range of several kHz to several MHz. Thus, the instantaneous power of the pulse can be substantially greater than the average power of the continuous X-ray beam generated by directing the electron beam towards a solid target, so typically the type of detector in the detector assembly 26 used to detect the beam 20 depends on the pulse rate.

[0049] In such embodiments, the detector of the detector assembly 26 may include a charge integral detector such as the PHOTON III detector supplied by Bruker (40 Manning Rd, Billerica, MA 01821) for pulse rates with frequencies in the kHz range, or a suitable detector from the JUNGFRAU detector family supplied by PSI (Switzerland, 5232 Villigen-PSI) for free electron lasers.

[0050] In other embodiments, the detectors (single or double) of the detector assembly 26 may include two-dimensional (2D) photon counting detectors, such as hybrid pixel array detectors (HPADs) like the Eiger series supplied by Dectris (Switzerland, Tafernweg 1, 5405 Baden). Specifically, for detecting an X-ray beam 20 having a frequency in the range of several MHz, the Dectris Eiger 2 product, designed for synchrotrons, is suitable. Alternatively, the detectors may include (i) one-dimensional (1D) strip detectors such as the LynxEye detector supplied by Bruker or the Mythen detector supplied by Dectris, or (ii) any preferred type of solid-state drift detectors.

[0051] In some embodiments, sample 18 may include a wafer formed from silicon, or any other semiconductor from column IV of the periodic table, such as germanium or a silicon-germanium alloy. Alternatively, sample 18 may include a wafer of compound semiconductor elements from columns III and V, or from columns II and VI, or from column III and nitrides or other materials. Furthermore, sample 18 may include a variety of thin-film materials, such as polymers, metals, metal alloys, and dielectric materials, deposited on the semiconductor to fabricate logic, memory, actuators, sensors, and other types of solid-state devices.

[0052] In other embodiments, sample 18 may include components used in state-of-the-art battery and display products that require analysis by various X-ray techniques. In yet another embodiment, sample 18 may include biological and / or chemical molecules and mechanisms that require analysis by X-ray crystallography, and at least some of these samples can be analyzed using the system configuration described in Figure 2 below. Also, in many industrial fields, such as the pharmaceutical and cement industries, X-ray powder diffraction is used for quality control. These samples can also be analyzed using the system configuration described in Figure 2 below.

[0053] Furthermore, sample 18 may also include any other sample that requires the determination of micro-stress and texture, typically used for materials research purposes, as well as in the automotive and aerospace industries.

[0054] In some embodiments, the beam monitor 17 is configured to generate an additional signal indicating the characteristics of the incident beam 16. The additional signal includes the intensity of a monochromatic beam or the intensity of a multichromatic beam at different X-ray energies and can be used to correct the analysis of changes in the characteristics of the incident beam 16 over a period of time. Furthermore, the processor 50 is configured to receive signals from an optical microscope and / or a camera (neither shown) indicating an image of the measurement site on the sample 18. In some embodiments, the processor 50 is configured to control the components and assemblies of the system 10 described above based on signals received from the detector assembly 26 and / or the beam monitor 17 and / or the optical microscope and / or camera. For example, the processor 50 is configured to control the laser light source 22 and / or XRS44 to adjust its operating parameters based on these signals in order to adjust the functionality and operation of the system 10 according to the requirements of any particular X-ray analysis application described above. Furthermore, the processor 50 is configured to control the stage 19 to move the sample 18 in the X, Y, and Z axes based on signals received from the optical microscope and / or camera.

[0055] In other embodiments, the system 10 includes a plurality (e.g., two) source optical systems 14 (not shown). The plurality of source optical systems 14 function as separate ports for a plurality of X-ray beams 12 emitted from a single XRS44. In such embodiments, the X-ray beams 12 emitted from the plurality of ports may be associated with a plurality of source optical systems 14 (not shown) that generate a plurality of incident beams 16 (not shown) having different or similar characteristics. In this configuration, the beams 16 are directed towards the sample 18 at their respective different angles or positions by the plurality of source optical systems 14. The scattered X-rays from the sample 18 are directed by a detector optical system so as to be detected by one or more detectors of a detector assembly 26.

[0056] Figure 2 is a schematic block diagram showing a transmission geometry-based X-ray analysis system 11 according to another embodiment of the present invention. For brevity, in this specification, the transmission geometry-based X-ray analysis system 11 is also referred to as system 11.

[0057] In some embodiments, the stage 19 of system 11 has a chuck 23 designed as an open frame (i.e., a frame without material in the center) to allow the incident beam 16 to strike the surface 25 of the sample 18 and scatter through the sample 18 and surface 27 as beam 20 toward the detector optics 24. In system 11, the XRS 44 and source optics 14 face the first side of the sample 18, while the detector optics 24 and detector assembly 26 face the opposite side of the sample 18. Furthermore, (i) all other components and assemblies of system 10, and (ii) the embodiments of operation described for system 10 in Figure 1 above, are also applicable to system 11.

[0058] These specific configurations of systems 10 and 11 are provided as examples to illustrate some of the problems addressed by embodiments of the present invention and to demonstrate the applicability of these embodiments to improving the performance of such X-ray analysis systems. However, embodiments of the present invention are by no means limited to these specific types of X-ray analysis systems, and the principles described herein can be similarly applied to other types of X-ray analysis systems.

[0059] Figure 3 is a cross-sectional view of a window assembly 66a according to an embodiment of the present invention. The window assembly 66a can replace, for example, the window assembly 66 shown in Figures 1 and 2.

[0060] In some embodiments, the X-ray enclosure 55 has an optically transparent window 65a configured to (i) allow the laser beam 33 to pass through and absorb it, and thus (ii) prevent the X-ray beams 12, 16, and 20 (as shown in Figures 1 and 2 above) from leaving the X-ray enclosure 55.

[0061] In some embodiments, the window assembly 66a is positioned inside the window 65a to (i) seal the window 65a to maintain a low vacuum level (e.g., about 10°C) inside the X-ray enclosure 55. -3 The device includes a sealant 67 configured to (i) maintain a pressure equal to or higher than torr, (ii) allow the laser beam 33 to pass through, and (iii) prevent the X-ray beams 12, 16, and 20 from escaping through the window 65a. In the example of Figure 3, the sealant 67 includes dense flint glass such as ZF7 glass containing lead (for example, with a mass density of about 5 grams per cubic centimeter, and therefore optically transparent and having the property of absorbing X-rays). However, the glass tends to brown over time due to the formation of color centers due to exposure to ionizing X-rays, which causes its light transmittance to decrease over time. ZF7 glass is supplied, for example, by CDGM Engineering, Inc. (Cannonsburg, Pennsylvania).

[0062] In some embodiments, the sealing material 67 is further configured to prevent air from entering the X-ray enclosure 55.

[0063] In other embodiments, the X-ray enclosure 55 is configured to operate at atmospheric pressure, and therefore instead of the sealing material 67, the window 65a can be filled with any suitable material (e.g., the ZF7 glass described above) configured to (i) allow the laser beam 33 to pass through the X-ray enclosure 65 and (ii) prevent the X-ray beams 12, 16 and 20 from escaping through the window 65a.

[0064] Figure 4 is a cross-sectional view of a window assembly 66b according to an embodiment of the present invention. The window assembly 66b can replace, for example, the window assembly 66 shown in Figures 1 and 2.

[0065] In some embodiments, the X-ray enclosure 55 is configured to operate at atmospheric pressure, as in the example in Figure 4. In such embodiments, the X-ray enclosure 55 has an opening 36 that can be left open or filled with a material that is transparent to the laser beam 33, instead of the sealed window 65a in Figure 3. In this configuration, the opening 36 can replace, for example, the window 65 in Figures 1 and 2.

[0066] In some embodiments, the window assembly 66b includes a labyrinth 77 configured to absorb any X-ray radiation (e.g., any of the X-ray beams 12, 16, and 20) passing through the window (e.g., the opening 36) of the X-ray enclosure 55 while not obstructing the path of the laser beam 33.

[0067] In some embodiments, the labyrinth 77 has an opening 34 and a compartment 35 defined by walls formed of an X-ray-opaque (or partially opaque) material. Furthermore, the compartment 35 is configured to surround (include) at least one prism 32 configured to refract the laser beam 33. In the example in Figure 4, the laser beam 33 enters the compartment 35 through the opening 34, is then refracted by the prism 32, and exits the compartment 35 through the opening 36, directed towards the X-ray enclosure 55. Note that the refractive index of X-rays is close to 1, while in this example the refractive index of the laser beam is approximately 1.5 to 2.0. Therefore, the labyrinth 77 is configured to bend the laser beam 33 and guide it into the X-ray enclosure 55, while the walls of the compartment 35 of the labyrinth 77 are configured to absorb X-ray radiation passing through the opening 36 (e.g., any of the X-ray beams 12, 16, and 20).

[0068] In other words, the window assembly 66b is coupled to the opening 36 which functions as the window 65 in Figures 1 and 2. In the example of Figure 4, the window assembly 66b is configured to (i) bend the laser beam 33 into the X-ray enclosure 55 and (ii) prevent one or more X-ray beams 12, 16 and 20 from leaving the X-ray enclosure 55.

[0069] In other embodiments, the labyrinth 77 may include one or more optical elements, which in this example are one or more further reflective and / or refractive elements configured to bend the laser beam 33. For example, the labyrinth 77 may include two sections: (i) a first section having a mirror or further prism configured to reflect or refract the laser beam 33, and (ii) a second section including a prism 32 and an opening between the first and second sections. Figure 6 below shows in detail one implementation example of a multi-section labyrinth.

[0070] In other embodiments, at least one of the openings 34 and 36 can be sealed with any preferred material, such as the sealing material 67 shown in Figure 3, which is placed inside it. In such embodiments, the sealing material 67 (i) seals at least one of the openings 34 and 36 to maintain a low vacuum level (e.g., about 10°C) inside the X-ray enclosure 55. -3 (ii) to maintain a pressure equal to or higher than torr, and to allow the laser beam 33 to pass through. Furthermore, as described in Figure 3 above, the seal material 67 is configured to prevent (or at least partially prevent) the X-ray beams 12, 16, and 20 from escaping through their respective openings, such as the opening 34. However, the walls of the labyrinth 77 are configured to absorb any X-ray radiation and prevent the X-ray radiation from escaping the X-ray enclosure 55. Thus, in order to maintain the vacuum level inside the X-ray enclosure 55, either or both of the openings 34 and 36 may be placed within the vacuum seal material that is transparent to the laser beam 33, even if it is not adapted to prevent the passage of X-ray radiation.

[0071] Figure 5 is a cross-sectional view of a window assembly 66c according to an embodiment of the present invention. The window assembly 66c can replace, for example, the window assembly 66 shown in Figures 1 and 2.

[0072] In some embodiments, the window assembly 66c includes a labyrinth 88 having a compartment 35 containing a mirror 41 instead of the prism 32 shown in Figure 4 above. In this configuration, the labyrinth 88 is configured to absorb any of the X-ray radiation that can pass through the opening 36 of the X-ray enclosure 55 (e.g., any of the X-ray beams 12, 16, and 20) while not obstructing the path of the laser beam 33.

[0073] In the example shown in Figure 5, the laser beam 33 enters the compartment 35 through the aperture 34, is then reflected by the mirror 41, and exits the compartment 35 through the aperture 36, directed into the X-ray enclosure 55.

[0074] In some embodiments, the prism 32 in Figure 4 and the mirror 41 in Figure 5 include any preferred prism and mirror configured to guide the laser beam 33. Such laser reflective and / or refraction components are supplied, for example, by Thor Labs (Newton 07860, New Jersey), Edmund Optics (101 East Gloucester Pike Barrington, New Jersey), and Newport (1791 Deere Avenue Irvine, CA 92606).

[0075] Figure 6 is a cross-sectional view of a window assembly 66d according to an embodiment of the present invention. The window assembly 66d can replace, for example, the window assembly 66 shown in Figures 1 and 2.

[0076] In some embodiments, the window assembly 66d includes a labyrinth 99 that defines compartments 37 and 39, each containing mirrors 42 and 43, and having walls that are opaque (or partially opaque) to X-rays. The labyrinth 99 has openings 38 and 36 within compartments 37 and 39, respectively. The opening 36 is located between the X-ray enclosure 55 and compartment 39. Furthermore, the labyrinth 99 has a wall 45 configured to separate compartments 37 and 39, and an opening 40 that allows a laser beam 33 to pass between compartments 37 and 39.

[0077] In the example shown in Figure 6, the laser beam 33 enters compartment 37 through the aperture 38, is then reflected by the mirror 42, and directed to enter compartment 39 through the aperture 40. The laser beam 33 then collides with the surface of the mirror 43 and is reflected, exiting compartment 39 into the X-ray enclosure 55 through the aperture 36.

[0078] In this configuration, the labyrinth 99 is configured to absorb any of the X-ray radiation that can pass through the aperture 36 (for example, any of the X-ray beams 12, 16, and 20) while not obstructing the path of the laser beam 33. Furthermore, having two compartments ensures that any X-ray radiation that can pass through the aperture 36 collides with more X-ray absorption walls (compared to, for example, the labyrinths 66b and 66c in Figures 4 and 5 above), thereby increasing the absorption of this X-ray radiation and preventing the emission of any X-ray radiation from the labyrinth 99.

[0079] In other embodiments, at least one of the mirrors 42 and 43 can be replaced with another reflective or refractive element. For example, mirror 43 can be replaced with a prism such as the prism 32 in Figure 4.

[0080] In another embodiment, the labyrinth 99 may include two or more sections containing more reflective and / or refractive elements that bend and guide the laser beam 33. In the example shown in Figures 4 to 6, the laser beam 33 is guided within approximately 90°. In other embodiments, the labyrinth 99 may include a preferred combination of any reflective or refractive elements positioned within sections 37 and 39 to guide the laser beam 33 using any preferred steering angles other than approximately 90°.

[0081] In other embodiments, at least one of the openings 38, 40, and 36 can be sealed with any preferred material, such as the sealing material 67 shown in Figure 3, which is placed inside it. In such embodiments, the sealing material 67 (i) seals at least one of the openings 38, 40, and 36 to maintain a low vacuum level (e.g., about 10°C) inside the X-ray enclosure 55. -3 (ii) it is configured to maintain a pressure equal to or higher than torr, and to allow the laser beam 33 to pass through. Furthermore, as described in Figure 3 above, the sealing material 67 may include ZF7 glass configured to prevent the X-ray beams 12, 16, and 20 from escaping through the aperture 36.

[0082] Figure 7 is a flowchart illustrating a schematic method for operating the X-ray analysis systems 10 and 11 using at least one of the window assemblies 66b to 66d shown in Figures 4 to 6, respectively, according to an embodiment of the present invention.

[0083] The method begins with the laser beam guidance step 100, and as described in detail in Figures 1 to 6 above, the laser beam 33 is bent toward the window assembly 66 and passed through the window 65 into the X-ray enclosure 55.

[0084] In the X-ray beam generation step 102, one or more X-ray beams 12 are generated by directing the laser beam 33 to collide with the liquid metal target of the XRS, as described in detail in Figure 1 above.

[0085] In the X-ray analysis step 104 that completes the method, the processor 50 directs the X-ray beam 33 (either in reflection geometry or transmission geometry) toward the sample 18, as detailed in Figures 3 to 6 above, detects the X-ray beam 20 scattered from the sample 18, and performs X-ray analysis at one or more measurement sites within the sample 18 by preventing the emission of any of the X-ray beams 12, 16, and 20 that may be emitted through the window 65 from exiting the window assembly 66. Note that in the configurations of Figures 4 to 6, the window assemblies 66b, 66c, and 66d are configured to bend the laser beam 33 and pass it into the X-ray enclosure 55, while in the configuration of Figure 3, the window assembly 66a is configured to pass the laser beam 33 into the X-ray enclosure 55 through the window 65a and the sealing material 67 without bending or guiding it.

[0086] Figure 8 is a flowchart illustrating the manufacturing method of X-ray analysis systems 10 and 11 according to embodiments of the present invention.

[0087] The method begins with an X-ray component and assembly placement step 110, in which (i) an XRS44 containing a liquid metal target, (ii) X-ray optical systems 14 and 24, (iii) stages 19 and 21 for moving the sample 18 and XRS44, respectively, and (iv) a detector assembly 26 are placed within an X-ray enclosure 55 having a window 65.

[0088] In some embodiments, the X-ray components and assemblies can be arranged in the form of the reflective geometry shown and described in Figure 1. In other embodiments, the X-ray components and assemblies can be arranged in the form of the transmission geometry shown and described in Figure 2.

[0089] In laser placement step 112, as described in detail in Figure 1 above, the laser light source 22 is placed outside the X-ray enclosure 55 to direct the laser beam 33 towards the XRS 44 through the window 65.

[0090] In the window assembly coupling step 114 that completes the method, as described in detail in Figures 3 to 6 above, (i) an X-ray beam 12 is generated by passing the laser beam 33 through the window 65 and causing it to collide with the liquid metal of the XRS 44, and (ii) the window assembly 66 is coupled to the window 65 of the X-ray enclosure 55 to prevent the emission of any of the X-ray beams 12, 16, and 20 that may be emitted through the window 65 from leaving the window assembly 66.

[0091] In some embodiments, the window assembly 66 is assembled to the X-ray enclosure 55 using either of the following preferred assembly techniques (e.g., adhesive or the use of suitable screws).

[0092] In other embodiments, the window assembly 66 can be manufactured together with the X-ray enclosure 55 as a single component or a pre-connected component.

[0093] These specific steps of the methods shown in Figures 7 and 8 are presented as simplified examples to illustrate some of the problems addressed by embodiments of the present invention and to demonstrate the applicability of these embodiments to improving the operation and manufacturing / assembly performance of such X-ray analysis systems. However, embodiments of the present invention are by no means limited to these specific methods and steps, and the principles described herein can be similarly applied to the operation and manufacturing of other types of X-ray analysis systems.

[0094] In some embodiments, the method shown in Figure 8 may include, but is not limited to, further steps such as incorporating a beam monitor 17, a processor 50, and other components and assemblies suitable for such an X-ray analysis system. Furthermore, the method shown in Figure 7 may include, but is not limited to, further steps such as controlling the generation of the laser beam 33 and the X-ray beam 12, as described in detail in Figure 1 above, and directing the X-ray beams 16 and 20 towards the sample 18 and the detector assembly 26 to perform X-ray analysis on a selected area of ​​the sample 18.

[0095] The embodiments described herein primarily relate to X-ray analysis systems having a liquid metal-based target. However, the methods and systems described herein can also be used in other applications, such as X-ray analysis systems having any other preferred type of X-ray target, such as a continuous metal wire having a diameter of approximately a few micrometers (μm) (e.g., less than approximately 10 μm) to approximately 1000 μm, or a metal strip whose dimensions along the YZ plane of the surface into which the laser beam strikes (e.g., in the YZ plane) are approximately 1 μm to approximately 1000 μm. The liquid metal-based target may include droplets of liquid metal or a continuous jet of liquid metal.

[0096] Furthermore, the disclosed technologies can also be used in a wide range of X-ray analysis techniques and applications, including, but are not limited to, (i) X-ray reflectivity (XRR) for analyzing thin films, (ii) X-ray diffraction (XRD) for analyzing polycrystalline materials, (iii) high-resolution XRD for analyzing epitaxial films and single-crystal substrates, (iv) X-ray fluorescence (XRF) for analyzing both thin and thick films, as well as various types of structures, (v) X-ray topography for imaging and analyzing single-crystal defects, (vi) single-crystal XRD for chemical analysis and biological crystallography, (vii) critical-dimensional small-angle X-ray scattering (CD-SAXS) for reflection and transmission, and / or (viii) high-angle low-energy X-ray scattering measurements at critical dimensions (XCD) for analyzing the shape and orientation of periodic arrays of nanostructures. These technologies and applications can be used individually or in hybrid analyses combined with the results of other technologies.

[0097] Accordingly, the embodiments described above are provided as examples, and it will be understood that the present invention is not limited to what is specifically illustrated and described herein. Rather, the scope of the present invention includes the various combinations and partial combinations of the features described herein, as well as variations and modifications of these not disclosed in the prior art, which will come to mind for those skilled in the art upon reading the above description. Documents incorporated into this patent application by reference should be considered integral parts of this application, except that, to the extent that any term in those incorporated documents is defined in a manner that contradicts the definitions provided herein, either explicitly or implicitly, only the definitions provided herein should be considered. [Explanation of Symbols]

[0098] 10 X-ray analysis systems 12 X-ray beam 14 Source optical system 15 Chuck 16 X-ray beams 17 Beam Monitor 18 samples 19 stages 20 X-ray beam 21 stages 22 Laser light source 24 Detector Optics 26 Detector Assembly 33 Laser beam 44 X-ray source assembly (XRS) 50 processors 55 X-ray safety enclosure 65 windows 66 Window Assembly

Claims

1. An X-ray analysis system comprising an X-ray enclosure and a window assembly, The X-ray enclosure includes (a) an X-ray source (XRS) configured to emit one or more X-ray beams in response to a laser beam colliding with the surface of the XRS, and (b) a window configured to prevent the emission of the one or more X-ray beams from leaving the X-ray enclosure, wherein the X-ray enclosure has a window configured to allow the laser beam to pass into the X-ray enclosure. The window assembly is coupled to the window and configured to (i) bend the laser beam to pass into the X-ray enclosure and (ii) prevent the emission of the one or more X-ray beams from leaving the X-ray enclosure.

2. The window assembly includes (i) an X-ray blocking labyrinth and (ii) one or more mirrors positioned within the X-ray blocking labyrinth and configured to bend the laser beam once or twice or more, The system according to claim 1.

3. The window assembly includes (i) an X-ray blocking labyrinth and (ii) one or more prisms positioned within the X-ray blocking labyrinth and configured to bend the laser beam once or twice or more, The system according to claim 1.

4. The aforementioned X-ray enclosure is 10 -3 It is configured to operate at a higher pressure than torr. The system according to any one of claims 1 to 3.

5. The aforementioned X-ray enclosure is configured to operate at atmospheric pressure. The system according to any one of claims 1 to 3.

6. The XRS comprises a liquid metal, and the one or more X-ray beams are emitted in response to the laser beams colliding with the liquid metal. The system according to any one of claims 1 to 3.

7. The XRS includes a target selected from a list of targets comprising at least one of (i) a continuous solid metal wire, (ii) a strip of solid metal, (iii) a droplet of liquid metal, (iv) a jet of continuous liquid metal, (v) a rotating drum coated with liquid metal, and (vi) a rotating disk coated with liquid metal, wherein one or more X-ray beams are emitted in response to the laser beams colliding with the target. The system according to any one of claims 1 to 3.

8. The laser beam is generated by a laser light source located outside the X-ray enclosure. The system according to any one of claims 1 to 3.

9. The one or more X-ray beams include pulses of the X-ray beams. The system according to any one of claims 1 to 3.

10. The pulses of the X-ray beam have a frequency of 1 kHz to 100 MHz. The system according to claim 9.

11. Receiving the laser beam directed towards the window of the X-ray enclosure, The laser beam is bent within a window assembly coupled to the window, and directed through the window toward the X-ray source (XRS) located in the X-ray enclosure. By causing the laser beam to collide with the XRS, one or more X-ray beams are emitted. The purpose is to prevent the emission of the one or more X-ray beams from leaving the X-ray enclosure, A method that includes this.

12. The window assembly comprises (i) an X-ray shielding labyrinth and (ii) one or more mirrors disposed within the X-ray shielding labyrinth, and bending the laser beam within the window assembly to direct the laser beam includes passing the laser beam between the one or more mirrors and bending the laser beam once or twice or more, and directing the laser beam toward the XRS through the window. The method according to claim 11.

13. The window assembly comprises (i) an X-ray blocking labyrinth and (ii) one or more prisms disposed within the X-ray blocking labyrinth, and bending the laser beam within the window assembly to direct the laser beam includes passing the laser beam between the one or more mirrors, bending the laser beam once or twice or more, and directing the laser beam towards the XRS through the window. The method according to claim 11.

14. The aforementioned X-ray enclosure is 10 -3 This includes operating at a pressure higher than torr. The method according to any one of claims 11 to 13.

15. This includes operating the aforementioned X-ray enclosure at atmospheric pressure. The method according to any one of claims 11 to 13.

16. The XRS comprises a liquid metal, and the emission of one or more X-ray beams includes directing the laser beam toward the liquid metal and emitting one or more X-ray beams by causing the laser beam to collide with the liquid metal. The method according to any one of claims 11 to 13.

17. Receiving the laser beam includes generating the laser beam in a laser light source located outside the X-ray enclosure and directing the laser beam toward the window, and emitting one or more X-ray beams includes emitting pulses of one or more X-ray beams. The method according to any one of claims 11 to 13.

18. A method for manufacturing an X-ray analysis system, The X-ray enclosure having a window comprises: (i) an X-ray source (XRS) for generating one or more X-ray beams; (ii) a detector assembly for generating a signal in response to the one or more X-ray beams colliding with a sample and then with the detector assembly; and (iii) an X-ray optical system for directing the one or more X-ray beams (a) from the XRS towards the sample and (b) from the sample towards the detector assembly. A laser light source for directing the laser beam towards the XRS through the window is placed outside the X-ray enclosure, The window of the X-ray enclosure is coupled with a window assembly having (i) an X-ray blocking labyrinth and (ii) one or more optical elements disposed within the X-ray blocking labyrinth for (a) bending the laser beam once or twice or more within the X-ray blocking labyrinth and (b) directing the laser beam through the window toward the XRS to generate one or more X-ray beams. A method that includes this.

19. The one or more optical elements for bending and directing the laser beam include at least one of (i) a mirror for reflecting the laser beam, and (ii) a prism for refracting the laser beam. The method according to claim 18.

20. The X-ray enclosure is opaque to the one or more X-ray beams, and the window is for allowing the laser beam to pass into the X-ray enclosure. The method according to claim 18 or 19.

21. Arranging the XRS includes arranging the XRS having a liquid metal target for generating the one or more X-ray beam pulses in response to the laser beam colliding with the liquid metal of the XRS, The method according to claim 18 or 19.

22. Arranging the XRS involves arranging the XRS having a target selected from a list of targets comprising at least one of (i) a continuous solid metal wire, (ii) a strip of solid metal, (iii) a droplet of liquid metal, (iv) a jet of continuous liquid metal, (v) a rotating drum coated with liquid metal, and (vi) a rotating disk coated with liquid metal, wherein the one or more X-ray beams are emitted in response to the laser beams colliding with the targets for generating the one or more X-ray beams. The method according to claim 18 or 19.

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