X-ray focusing and wavelength selection

Abstract

X-ray optics comprising: (i) achromatic collimation optics adapted to collimate an input X-ray beam to provide a collimated X-ray beam; (ii) an adjustable diffraction unit adapted to: (a) receive the collimated X-ray beam while being configured according to a current configuration associated with a current wavelength selected from among the different wavelengths, the current configuration being selected from among the different configurations associated with the different wavelengths; and (b) filtering the collimated X-ray beam to provide a filtered collimated X-ray beam of a current wavelength; and (iii) achromatic focusing optics configured to focus the filtered collimated X-ray beam to provide a focused filtered X-ray beam.

Description

[0001] Cross-references

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 492,246, filed on March 26, 2023, which is incorporated herein by reference. Background Art

[0003] In semiconductor metrology environments, X-ray metrology typically requires a compact X-ray transmission and focusing system. Due to the high cost of fab space, the high-brightness X-ray sources used by many national laboratories utilizing synchrotron radiation (SR) and free electron lasers (FELs) are not only too expensive to operate but also too large to be used for metrology and inspection.

[0004] Other more scalable high-brightness X-ray sources include electron beam-induced gas or solid plasma sources, electron beam-generated X-rays from solid targets (fluorescence of bremsstrahlung), and electron beam / liquid metal jet sources. Some selected representative metrology applications include X-ray scattering (XRS), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), X-ray fluorescence (XRF), total reflection X-ray fluorescence (TXRF), and X-ray photoelectron spectroscopy (XPS). Each of these applications requires a different excitation X-ray energy (wavelength) range and, therefore, a different focusing or collimation system, as well as differences in the X-ray energy bandwidth.

[0005] These systems are not flexible.

[0006] The demand for more flexible systems is constantly growing. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, the invention, both as to its organization and method of operation, together with objects, features, and advantages thereof, may be best understood by reference to the following detailed description when read with the accompanying drawings, in which:

[0008] Figures 1 to 7 An example of X-ray optics is shown;

[0009] Figure 8 Shown are examples of the relationship between the Bragg angle and the X-ray wavelength for some selected monochromator / diffractor crystals from 0.6A to 20A, and examples of the relationship between the Bragg angle and the X-ray wavelength for some selected monochromator / diffractor crystals from 20A to 120A;

[0010] Figures 9 and 10 An example of X-ray optics is shown;

[0011] Figures 11 to 12 An example of a method is shown;

[0012] Figure 13 An example of focusing an X-ray beam from a finite X-ray source via an ellipsoidal monochromator or an annular monochromator is shown;

[0013] Figure 14 An example of the reflectivity of a multilayer substrate at a fixed angle in the energy range from 100 eV to 1000 eV is shown, with strong suppression of other incident X-ray lines;

[0014] Figure 15 An example of X-ray focusing via a Schwarzschild objective lens using a multilayer coating for low-energy X-rays is shown;

[0015] Figure 16 An example of a multilayer zone plate with tilted interfaces to satisfy the Bragg angle is shown;

[0016] Figure 17 An example of X-ray transmission through a polycapillary lens is shown; and

[0017] Figure 18 An example of X-ray transmission via reflective (Type I Walters) optics is shown. DETAILED DESCRIPTION

[0018] A flexible X-ray microfocusing system for XPS / XRF metrology applications is presented. This system uses different X-ray energies and energy bandwidths as representative, but not exclusive, examples, and can be easily extended to other metrology use cases. Specifically, a method for focusing monochromatic X-ray beams of multiple, selectable energies onto a wafer surface is described. A flexible method for operating the system is also provided.

[0019] A flexible X-ray focusing system is provided that includes dedicated X-ray optics that are not optimized for a single, specific X-ray energy. The system exhibits high performance and flexibility, in contrast to prior art dedicated X-ray monochromatic focusing systems that lack flexibility and achieve this performance at the expense of flexibility. The system is more cost-effective than prior art systems where the cost factor becomes prohibitive in situations where a wider range of X-ray energies would be beneficial for an application (i.e., using two or more monochromator focusing systems for two or more X-ray energies). A method is described for enabling an X-ray beam delivery system to focus a plurality of selectable and monochromatic X-ray energies (wavelengths) to a metering site. An X-ray target from a gas, solid, or liquid metal jet high brightness X-ray source generates not only characteristic X-ray lines from the target, but also a continuous radiation of varying intensity, i.e., Bremsstrahlung.

[0020] High-intensity continuous radiation can be used as an excitation source for specific applications, particularly if a compact X-ray focusing system can provide a continuously or quasi-continuously tunable monochromatic X-ray beam that can be focused to the metrology site. X-ray focusing systems with discretely selectable X-ray energies can be used. X-ray focusing systems can consist of, but are not limited to, fixed focusing elements combined with monochromator crystals or multilayer films.

[0021] As a representative example, the angle θ from the X-ray source a to the b A second, counter-point-pair paralleling optic is placed at the exit angle of the monochromator crystal to focus the X-ray beam to the metrology site.

[0022] According to an embodiment, there is provided an X-ray optical device comprising:

[0023] a. Achromatic collimating optics adapted to collimate an input X-ray beam to provide a collimated X-ray beam.

[0024] b. An adjustable diffraction unit adapted to: (a) receive a collimated X-ray beam while being configured according to a current configuration associated with a current wavelength selected from different wavelengths, wherein the current configuration is selected from different configurations associated with different wavelengths; and (b) filter the collimated X-ray beam to provide a filtered collimated X-ray beam of the current wavelength.

[0025] c. Achromatic focusing optics configured to focus the filtered collimated X-ray beam to provide a focused filtered X-ray beam.

[0026] According to an embodiment, the adjustable diffraction unit comprises different diffraction elements associated with different wavelengths.

[0027] According to an embodiment, the current configuration includes positioning one of the adjustable diffractive elements in the path of the collimated X-ray beam (while the other adjustable diffractive elements are located outside of the path).

[0028] According to an embodiment, positioning comprises at least one of the following:

[0029] a. Moving at least some of the different diffractive elements.

[0030] b. Moving other elements of the X-ray optics (such as achromatic collimating optics and / or achromatic collimating optics) with respect to at least some of the different diffractive elements.

[0031] c. Move the position of the input X-ray beam - using mechanical means and / or optical means.

[0032] Depending on the embodiment, the movement is along one axis, along multiple axes, linear, non-linear, rotational, etc.

[0033] According to an embodiment, the diffractive element is a grating, a multilayer diffractor or any other diffractive element.

[0034] According to an embodiment, different diffractive elements are associated with different wavelengths.

[0035] According to an embodiment, different diffractive elements exhibit different lattice spacings.

[0036] Depending on the embodiment, different diffractive elements exhibit different compositions.

[0037] According to an embodiment, the diffractive elements are different plane gratings associated with different wavelengths.

[0038] According to an embodiment, the different diffractive elements are arranged in an array or in a disordered manner. The array can be a linear array, a multi-dimensional array, a radially symmetric array or any other non-linear array.

[0039] According to an embodiment, the different diffraction elements are arranged in a linear array and wherein the configuration unit is configured to move one of the different diffraction elements into the path of the collimated X-ray beam.

[0040] According to an embodiment, the different diffraction elements are connected to the turret, and wherein the configuration unit is configured to move one of the different diffraction elements into the path of the collimated X-ray beam.

[0041] According to an embodiment, the different diffractive elements comprise different ellipsoidal monochromators associated with different wavelengths.

[0042] According to an embodiment, the different diffractive elements further comprise reduction optics.

[0043] According to an embodiment, the X-ray optics comprises a configuration unit for selecting one of the different diffraction elements to interact with the collimated X-ray beam.The configuration unit may be a controller.

[0044] According to an embodiment, the adjustable diffraction unit includes: a diffraction element; and a configuration unit configured to determine a Bragg condition of the diffraction element.

[0045] According to an embodiment, the configuration unit is configured to set the optical axis of the collimated X-ray beam, the optical axis of the filtered collimated X-ray beam and a distance between the diffraction element and at least one of the collimating optics or the focusing optics.

[0046] According to an embodiment, the configuration unit is configured to set the optical axis of the collimated X-ray beam by rotating the collimating optics and to set the optical axis of the filtered collimated X-ray beam by rotating the focusing optics while maintaining a constant source-to-focus distance.

[0047] According to an embodiment, the adjustable diffraction unit comprises different diffraction elements associated with different wavelengths, wherein the different diffraction elements comprise diffraction elements, and wherein the configuration unit is further configured to select one of the diffraction elements to interact with the collimated X-ray beam.

[0048] Figures 1 to 2 Several diffraction elements are shown, such as crystal diffractors 31(1) to 31(8) having the same Bragg condition, arranged side by side and movable along a first axis 32 for selecting one of the crystal diffractors at a given moment. Figure 1 The first crystal diffractometer 31(1) was selected in Figure 2 The third crystal diffractor 31(3) is selected.

[0049] Figure 1 and Figure 2 Both also show a source 20 , an initial light spot 21 formed on the source, input X-rays 22 collimated by an achromatic collimating optic 23 adapted to collimate the input X-ray beam to provide a collimated X-ray beam 24 .

[0050] The collimated X-ray beam 24 is incident on a selected crystal diffractor (associated with the current wavelength), which filters the collimated X-ray beam to provide a filtered collimated X-ray beam 25 exhibiting the current wavelength.

[0051] Achromatic focusing optics 26 are configured to focus the filtered collimated X-ray beam 25 to provide a focused filtered X-ray beam 27 that is incident on a target 29 and forms a spot 28 on the target. The target may be a sample or a portion of a sample.

[0052] Figure 3 Examples are shown of moving different crystal diffractors 31(1) to 31(8) using linear movement along one axis (see dashed arrow 32), linear movement along two axes (see dashed arrow 32-1), rotational movement (see dashed arrow 32-2), and using different holders 33 to provide mechanical coupling between the different crystal diffractors and a moving element such as a rotary motor 36, a linear motor 34, or a 2-axis motion unit 35. Depending on the embodiment, the movement is controlled by a controller 60, which may include one or more portions of one or more integrated circuits.

[0053] For example, for an assumed Bragg angle of 60 degrees, Figures 1 to 2The X-ray optics are available at fixed height and fixed angle using selectable monochromator crystals for the following X-ray energies as listed in Table 1:

[0054]

[0055]

[0056] Table 1 shows the approximate transmitted and focusable X-ray energies for different monochromator crystals and multilayers assuming a fixed Bragg angle of 60 degrees and achromatic input and output optics.

[0057] Multilayer diffractors can be optimized for different X-ray energies by utilizing different material combinations, layer ratios and thicknesses, and the number of layers on the substrate. This applies to both WSi and CrTi multilayers.

[0058] Figures 1 to 2 An example is shown of transmitting X-rays from an X-ray source via point-to-point parallel optics to a monochromator and focusing the resulting monochromatic, discretely selectable X-ray beam to a metrology site.

[0059] Figure 4 A diagram of six crystals or multilayer diffractors 31(1) to 31(6) mounted in a turret 37 rotatable about an axis is shown. Figure 4 Also shown are source 20, initial spot 21, input X-rays 22, achromatic collimating optics 23, collimated X-ray beam 24, filtered collimated X-ray beam 25, achromatic focusing optics 26, focused filtered X-ray beam 27, target 29 and spot 28.

[0060] Figure 5 Shown with Figure 1 The X-ray optics are different from the X-ray optics - by keeping the crystal diffractor static and moving other parts of the X-ray optics - such as the achromatic collimating optics 23 (moved using the collimating optics motion unit 42) and the achromatic focusing optics 26 (moved using the focusing optics motion unit 43) and / or by moving the X-ray source (at the position of the spot 22) - using the source motion unit 41. The linear movement is shown by the dashed arrow 32.

[0061] According to an embodiment, by changing the combined tilt of the input and output optics (eg, comprising achromatic collimating optics 23 and achromatic focusing optics 26, respectively) to change the Bragg conditions, a more flexible method enabling quasi-continuous X-ray focusing can be achieved.

[0062] Figure 6 and Figure 7Two different positions (heights or distances from the target) of the diffraction element 31-1 are shown, which are associated with different Bragg angles and different tilt angles (see curved arrows 32-2 indicating rotational movement) of the achromatic collimating optics 23 and the achromatic focusing optics 26. The collimating optics rotation unit 45 rotates the achromatic collimating optics 23. The focusing optics rotation unit 46 rotates the achromatic focusing optics 26.

[0063] Since changing the Bragg angle (indicated by 51 and 52) also modifies the outgoing monochromatized X-ray beam towards the final focusing optics, the distances of the crystal to the input focusing optics and the final focusing optics must be changed simultaneously.

[0064] For shallower Bragg angles, i.e., higher energy X-ray transmission, it is necessary to reduce the distance from the emission point to the diffractor crystal, move the diffraction stage system closer to the incident parallel X-ray beam, and perform opposite angular compensation of the focusing optics (opposite sign or source focusing optics) to achieve a stationary fixed X-ray spot at the metrology site.

[0065] Figure 6 and Figure 7 The X-ray optics can be used for fixed source-to-meter distances. In particular, the X-ray transmission from source to target (metering site) and the semi-continuous X-ray energy transmission are very flexible and can provide solutions for continuous or semi-continuous wavelength ranges.

[0066] Figure 8 Graph 71 in shows the relationship between the Bragg angle and the X-ray wavelength for some selected monochromator / diffractor crystals ranging from 0.6A to 20A.

[0067] Figure 9 Graph 72 in FIG. 7 shows the relationship between the Bragg angle and the X-ray wavelength for some selected monochromator / diffractor crystals between 20 A and 120 A. The graph shows the applicable X-ray wavelength range for some representative monochromator / diffractor crystals.

[0068] The focusing input and output optics may comprise nested Walters optics including a central polycapillary optic. The input and output optics may have different focal lengths.

[0069] The more flexible approach described above can be extended using a set of several monochromator crystals mounted on a turntable or linear translator that can be moved into the incident X-ray beam path.

[0070] The proposed solution provides a compact system, which is a step-by-step energy-selectable X-ray focusing system for semiconductor metrology. The system is capable of delivering and focusing a monochromatic X-ray beam spanning and applicable to X-rays from approximately 100 eV to several keV.

[0071] The system is a compact, quasi-continuous X-ray energy focusing system used to guide and focus a monochromatic X-ray beam onto a metrology site. The system is capable of delivering and focusing monochromatic X-ray beams spanning and applicable to X-rays from approximately 100 eV to several keV.

[0072] The above solution may exhibit at least one of the following:

[0073] a. X-ray transmission from a polychromatic or partially monochromatic X-ray source beam with a diameter less than 100 μm is performed through an optical device configuration to form a monochromatic focus at the analysis site.

[0074] b. A system for collecting X-rays, monochromatizing the X-ray beam and then focusing it to an analysis site.

[0075] c. Provide X-ray focusing of a monochromatized X-ray beam of step-selectable energy, which is focused onto the metrology site.

[0076] d. An X-ray focusing system with continuously adjustable energy within a limited X-ray energy range.

[0077] Figure 9 and Figure 10 An example of an X-ray optics comprising:

[0078] a. A focusing monochromator 110 configured to: (i) receive a non-collimated input X-ray beam 109, wherein the non-collimated input X-ray beam forms a first spot 103 on the target at a first plane 108; and (ii) filter and focus the non-collimated X-ray beam to provide a filtered focused X-ray beam 116 at a current wavelength. Depending on the embodiment, the focusing monochromator is an ellipsoidal monochromator or an annular monochromator.

[0079] b. The demagnification achromatic optical device 117 is configured to demagnify the filtered focused X-ray beam of the current wavelength to form a target spot 119 smaller than the first spot 103 at the sample plane 120. The demagnification achromatic optical device 117 outputs another non-collimated X-ray beam 119.

[0080] According to an embodiment, the first light spot is imaged onto a second plane 115 located between the focusing monochromator 110 and the demagnifying achromatic optics 117. The first plane 108 and the second plane 115 are conjugate planes.

[0081] exist Figure 9, the X-ray optics further include an imaging achromatic optics 105 that receives an input X-ray beam 104. The X-ray beam 104 is generated by irradiating a target with a laser beam 102 (generated by a laser source 101) to form a spot 103 on the target. The imaging achromatic optics 105 outputs another non-collimated X-ray beam 106 that forms a spot 107 at a first plane 108.

[0082] exist Figure 10 In FIG. 1 , an X-ray beam source (eg, a target irradiated with a laser beam 102 generated by a laser source 101 ) is located at a first plane.

[0083] According to the embodiment, Figure 9 The X-ray optics of either or 10 may be part of an adjustable X-ray optics.

[0084] According to an embodiment, an X-ray optics is provided comprising different focusing monochromators associated with different wavelengths.

[0085] Zoom

[0086] According to an embodiment, the collection efficiency and final spot size of the X-ray focusing system for a specific single X-ray energy are controlled or improved by using focusing optical devices to image the X-ray source emission spot to the focus of an ellipsoidal or annular monochromator for a specific X-ray energy.

[0087] The monochromatic X-ray focus of the monochromator is imaged onto the wafer surface. Alternatively, a second optical device is placed at the conjugate image position of the monochromator to image / reduce the monochromatic X-ray beam spot onto the wafer.

[0088] An ellipsoidal or annular monochromator, whose source is placed conjugately at the X-ray source emission region, produces a monochromatic focus at the image conjugate point / distance for a specific X-ray energy.

[0089] Focusing optics placed at the monochromator image spot can be used to scale the monochromatic image onto the wafer, creating a smaller spot size than that produced at the monochromator focus.

[0090] The imaging optics can be achromatic reflective optics or polycapillary optics.

[0091] According to an embodiment, an X-ray optical device is provided, comprising an X-ray collection system configured to focus a polychromatic source at the source conjugate of a focusing monochromator (ellipsoidal or annular) and to demultiply the image conjugate of the monochromator onto a wafer or mask metrology site via a total focusing optic. The final focus on the target (e.g., wafer) will be smaller than the spot size achievable with the monochromator alone—see, e.g., Figure 9 and Figure 10 .

[0092] According to an embodiment, source imaging optics are employed to optimize the X-ray collection efficiency from the X-ray source to the (focusing) monochromator source conjugate in order to minimize / optimize the size and shape of the monochromator for lower brightness X-ray sources.

[0093] According to embodiments, by placing a demagnifying achromatic X-ray optics (reflective or polycapillary) at the image conjugate of a fixed-magnification monochromator, the X-ray optics are simplified and selectable demagnification ratios of ellipsoidal or annular monochromators are provided. As a result, the final X-ray spot size at the wafer metrology site can be monochromatic and smaller than that achievable using only a focusing monochromator.

[0094] According to an embodiment, the proposed reduction ratio is applied to Figure 13 The optics shown in or other X-ray optics.

[0095] Figure 11 An example of a method 200 for manipulating input X-rays is shown.

[0096] According to an embodiment, the method 200 includes step 210 of collimating an input X-ray beam by an achromatic collimating optical device to provide a collimated X-ray beam.

[0097] According to an embodiment, step 210 is followed by step 220 of receiving the collimated X-ray beam by the adjustable diffraction unit while being configured according to a current configuration associated with a current wavelength selected from different wavelengths, the current configuration being selected from different configurations associated with different wavelengths.

[0098] According to an embodiment, step 220 is followed by step 230 of filtering the collimated X-ray beam by the adjustable diffraction unit to provide a filtered collimated X-ray beam at the current wavelength.

[0099] According to an embodiment, step 230 is followed by step 240 of focusing the filtered collimated X-ray beam by achromatic focusing optics to provide a focused filtered X-ray beam.

[0100] According to an embodiment, the method 200 is performed by Figures 1 to 7 Any of the X-ray optics shown in any one of the implementations.

[0101] According to an embodiment, the method 200 comprises: selecting a current configuration and / or receiving a request or instruction to apply the current configuration; and configuring 205 the adjustable diffractive element to the current configuration.

[0102] The specifics of the current configuration may change over time.

[0103] Examples of configurations include:

[0104] a. Moving at least some of the different diffractive elements.

[0105] b. Moving other elements of the X-ray optics (such as achromatic collimating optics and / or achromatic collimating optics) with respect to at least some of the different diffractive elements.

[0106] c. Move the position of the input X-ray beam - using mechanical means and / or optical means.

[0107] d. Move the adjustable diffractive element and / or change the tilt angle of various optical devices.

[0108] Figure 12 An example of a method 300 for manipulating X-rays is shown.

[0109] According to an embodiment, the method 300 includes step 310 of receiving a non-collimated input X-ray beam by a focusing monochromator, wherein the non-collimated input X-ray beam forms a first spot at a first virtual plane.

[0110] According to an embodiment, step 310 is followed by step 320 of filtering and focusing the non-collimated X-ray beam by a focusing monochromator to provide a filtered focused X-ray beam at the current wavelength.

[0111] According to an embodiment, step 330 is followed by step 340 of demagnifying the filtered focused X-ray beam at the current wavelength by a demagnifying achromatic optical device to form a target spot smaller than the first spot at the sample plane.

[0112] According to an embodiment, the first light spot is imaged onto a second plane located between the focusing monochromator and the demagnifying achromatic optics, wherein the first plane and the second plane are conjugate planes.

[0113] According to an embodiment, the X-ray beam source is located at the first plane.

[0114] According to an embodiment, the method 300 includes imaging a spot formed by an X-ray beam source onto a first plane by an imaging achromatic optical device.

[0115] Any combination of any steps of method 200 and method 300 may be provided.

[0116] According to an embodiment, the method 300 is performed by Figure 9 or Figure 10 Any X-ray optics is performed in

[0117] Various examples from other systems

[0118] The most commonly used X-ray energy in XPS is AlKα (1486.7 eV), which is typically transmitted and focused onto the wafer surface via a monochromator to reduce the natural linewidth of the emission lines used for chemical state identification. The photoelectrons generated by AlKα radiation will have a maximum kinetic energy of about 1486.7 eV, limiting the analytical depth to about 10 nm and providing a limited range of secondary X-ray fluorescence lines that can be detected simultaneously and can serve as an independent and complementary input parameter for the total dose of the material being analyzed. The most commonly used focusing and monochromator system consists of an ellipsoidal or toroidal substrate filled with a quartz wafer (see Figure 13 ) and delivers a point-to-point focus of the target emission to the sample surface with an energy bandwidth of approximately 0.5 eV. The advantage of these systems is that monochromators can be manufactured with a large angular acceptance and therefore high transmission efficiency. Such monochromator focusing systems can also transmit when optimized for the first order Bragg diffraction of AlKα, and can also focus discrete higher order diffraction orders (energies) to the wafer surface according to nλ = 2d sin(θ) (d is the lattice spacing). However, the coverage of the focusable energy is inherently discrete, and other intermediate energies other than the nλ equivalent cannot be transmitted to the sampling area by design. Using such a monochromator, it is impossible to acquire or focus lower energy X-rays at the sample surface, and a larger 2d lattice spacing needs to be applied to the substrate.

[0119] The system can monochromatize and focus different X-ray wavelengths λ given by hc / E, where h is Planck's constant, c = the speed of light, and E is the X-ray energy, which can be generated by applying crystals of different crystal plane orientations and / or crystal materials to an ellipsoidal substrate. Only the X-ray energy that can be monochromatized and focused onto a wafer site is limited by nλ = 2d sin(θ) or E = n / [(hc)2d sin(θ)], with the lower cutoff being determined by the 2d lattice spacing. The higher the first order diffraction energy, the greater the energy difference between higher diffraction orders.

[0120] Generally speaking, monochromator crystals for higher energy ranges require smaller 2d lattice spacings and are readily available in a variety of crystal orientations and crystals. These crystals can be applied to a substrate and focus the monochromated X-rays onto the sampling area.

[0121] For X-ray energies requiring a 2d lattice spacing greater than 27 Å, natural crystals with a defined lattice structure are no longer available and multilayer mirror monochromators are used. A multilayer can be deposited on a substrate (e.g. an ellipsoidal substrate) to focus a monochromatic X-ray beam from an X-ray source onto a sampling surface. A specific example would be the use of a W / Ti multilayer with a 1.4 nm period and a 0.55 relative layer thickness, with three hundred repeating layers arranged on a substrate. For example, for an X-ray energy of 452.2 eV (Ti Lα), the maximum reflectivity is 25% under ideal conditions at a Bragg angle of 78.3 degrees (cxro website). This engineered multilayer on the substrate provides a monochromatic X-ray beam that can be focused onto a wafer substrate (see Figure 13 and Figure 14 ).

[0122] Following this approach, such multilayer structures can be deposited on other optical systems, such as Schwarzschild objectives with appropriate focusing geometry, to provide a substantially monochromatic and focused beam spot on the target sampling area (see Figure 15 Schwarzschild optics are mainly suitable for the low-energy X-ray range in the water window, as they require a near-vertical reflection geometry, i.e., a Bragg angle in the range >80 degrees and <90 degrees.

[0123] Zone plate optics represent another type of energy selective focusing system and are usually based on multiple layers. These systems can be used in Laue transmission ( Figure 16 Schematic diagram of a multilayer zone plate with tilted interfaces to satisfy the Bragg angle) mode or to provide focusing in a reflective configuration. The principle is based on a set of concentric ellipses of increasing size around an object point with a common focus (source-object point) to satisfy the Bragg diffraction condition on a larger diameter: r n = =sqrt[(nλ / 2) 2 +nλf|, where f is the focal length.

[0124] The resolution of the zone plate is determined by the width of the outermost zone.

[0125] A reflective off-axis zone plate structure with appropriate geometry can be deposited on a substrate to provide spatially separated X-ray images according to the incident wavelength of a polychromatic incident X-ray beam.

[0126] Non-energy selective (achromatic) focusing systems operate using either total external reflection or total internal reflection. For X-ray energies well above 2 to 3 keV, the most commonly used focusing optics are polycapillary optics. The focusing system consists of a bundle of glass capillaries that can be shaped to provide point-to-parallel, parallel-to-point, or point-to-point foci and utilizes total internal reflection (see Figure 17 —Schematic diagram of X-ray transmission through a polycapillary lens).

[0127] For lower energy ranges, polycapillary optics are generally less efficient than shaped reflective optic mirrors due to the higher critical angles of metal coated surfaces (e.g., Pt or other metal coatings). Reflective optics can be shaped to provide focusing conditions similar to polycapillary systems, i.e., point-to-parallel, parallel-to-point, or point-to-point focus. The shape of reflective optics for point-to-parallel X-ray transmission is effectively a parabola, shaped to match a given working distance, such as Figure 16 Single-reflection optics must be true parabolic in shape and can achieve high efficiency in the X-ray energy range of several keV (depending on the metal coating). Types 1 to 3 Walters optics also utilize total internal reflection, using a double-reflection geometry to focus a nearly parallel beam to a point (and conversely convert the point to a parallel beam) using nested parabolic and elliptical reflectors (see Figure 18 —Schematic diagram of X-ray transmission through reflective (Type I Walters) optics.

[0128] In selected applications, reflective Walter optics and polycapillary optics have been used in combination to increase the wavelength range of collimating or focusing optics, i.e., polycapillary optics inside the Walter optic.

[0129] In the foregoing detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other cases, well-known methods, processes, and components have not been described in detail in order to avoid obscuring the present invention.

[0130] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification.The invention, however, both as to its organization and method of operation, together with objects, features, and advantages thereof, may be best understood by reference to the following detailed description when read with the accompanying figures.

[0131] It should be understood that for simplicity and clarity of illustration, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. In addition, where deemed appropriate, reference numerals may be repeated in the figures to indicate corresponding or similar elements.

[0132] Because the illustrated embodiments of the present invention can for the most part be implemented using electronic components and circuits known to those skilled in the art, details will not be explained to any greater extent than is deemed necessary in the foregoing description in order to understand and appreciate the basic concepts of the invention and in order not to obscure or distract from the teachings of the invention.

[0133] Any reference in the specification to a method should apply mutatis mutandis to a system capable of performing that method.

[0134] Any reference in the specification to a system shall apply mutatis mutandis to a method that may be performed by the system.

[0135] In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention as set out in the appended claims.

[0136] Furthermore, the terms "front," "back," "top," "bottom," "upper," "lower," and the like, if any, in the specification and claims are used for descriptive purposes and are not necessarily intended to describe permanent relative positions. It is understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

[0137] The connection discussed herein can be any type of connection suitable for, for example, transmitting a signal out of or into a corresponding node, unit or device via an intermediate device. Therefore, unless otherwise implied or elaborated, the connection can be, for example, a direct connection or an indirect connection. Connections can be illustrated or described with reference to a single connection, multiple connections, a unidirectional connection or a bidirectional connection. However, different embodiments can vary the implementation of the connection. For example, a separate unidirectional connection can be used instead of a bidirectional connection, or vice versa. In addition, multiple connections can be replaced by a single connection that transmits multiple signals serially or in a time-multiplexed manner. Similarly, a single connection that carries multiple signals can be separated into various different connections that carry a subset of these signals. Therefore, there are many options for transmitting signals.

[0138] Although specific conductivity types or polarity of potentials have been described in the examples, it should be understood that the conductivity types and polarity of potentials can be reversed.

[0139] Each signal described herein can be designed as either positive logic or negative logic. In the case of a negative logic signal, the signal is active low, where the logically true state corresponds to a logic level 0. In the case of a positive logic signal, the signal is active high, where the logically true state corresponds to a logic level 1. Note that any of the signals described herein can be designed as either a negative logic signal or a positive logic signal. Therefore, in alternative embodiments, those signals described as positive logic signals can be implemented as negative logic signals, and those signals described as negative logic signals can be implemented as positive logic signals.

[0140] Furthermore, the terms "assertion" or "setting" and "negation" (or "de-assertion" or "clearing") are used herein when referring to a signal, status bit, or the like assuming its logically true or logically false state, respectively. If the logically true state is a logic level 1, the logically false state is a logic level 0. If the logically true state is a logic level 0, the logically false state is a logic level 1.

[0141] Those skilled in the art will recognize that the boundaries between logic blocks are merely illustrative, and that alternative implementations may merge logic blocks or circuit elements, or impose alternative functional decompositions on various logic blocks or circuit elements. Therefore, it should be understood that the architectures depicted herein are merely exemplary, and that in fact many other architectures that achieve the same functionality may be implemented.

[0142] Any arrangement of components that achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Thus, any two components herein combined to achieve a particular functionality may be considered to be "associated" with each other such that the desired functionality is achieved, regardless of architecture or intermediary components. Likewise, any two components so associated may also be considered to be "operably connected" or "operably coupled" to each other such that the desired functionality is achieved.

[0143] Furthermore, those skilled in the art will recognize that the boundaries between the above-described operations are illustrative only. Multiple operations may be combined into a single operation, a single operation may be distributed among additional operations, and operations may be performed with at least partial overlap in time. Furthermore, alternative embodiments may include multiple instances of a particular operation, and the order of the operations may be altered in various other embodiments.

[0144] For another example, in one embodiment, the illustrated examples may be implemented as circuits located on a single integrated circuit or within the same device. Alternatively, the examples may be implemented as any number of separate integrated circuits or separate devices interconnected with each other in a suitable manner.

[0145] However, other modifications, variations, and substitutions are possible. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0146] In the claims, any reference numerals placed between brackets should not be interpreted as limiting the claims. The word "comprising" does not exclude the presence of other elements or steps other than those listed in the claim. In addition, the terms "one" or "an" as used herein are defined as one or more than one. In addition, the use of introductory phrases (such as "at least one" and "one or more") in the claims should not be interpreted as implying that any particular claim containing such introduced claim elements by the indefinite article "one" or "an" to another claim element is limited to an invention containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and the indefinite article (such as "one" or "an"). This is also true for the use of definite articles. Unless otherwise stated, terms (such as "first" and "second") are used to arbitrarily distinguish the elements described by such terms. Therefore, these terms are not necessarily intended to indicate the time or other priority of such elements. The mere fact of reciting certain measures in mutually different claims does not indicate that the combination of these measures cannot be used to bring advantages.

[0147] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It should be understood, therefore, that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the invention.

Claims

1. An X-ray optical device, comprising: an achromatic collimating optic adapted to collimate an input X-ray beam to provide a collimated X-ray beam; an adjustable diffraction element adapted to: (a) receive the collimated X-ray beam while being configured according to a current configuration associated with a current wavelength selected from among different wavelengths, the current configuration being selected from among different configurations associated with the different wavelengths; and (b) filter the collimated X-ray beam to provide a filtered collimated X-ray beam of the current wavelength; as well as Achromatic focusing optics are configured to focus the filtered collimated X-ray beam to provide a focused filtered X-ray beam.

2. The X-ray optical device according to claim 1, wherein The adjustable diffraction unit includes different diffraction elements associated with the different wavelengths.

3. The X-ray optical device according to claim 2, wherein: The different diffractive elements exhibit different lattice spacings.

4. The X-ray optical device according to claim 2, wherein: The different diffractive elements exhibit different compositions.

5. The X-ray optical device according to claim 2, wherein: The different diffraction elements are different plane gratings associated with the different wavelengths.

6. The X-ray optical device according to claim 2, wherein: The different diffraction elements are arranged in a linear array, and wherein the configuration unit is configured to move one of the different diffraction elements into the path of the collimated X-ray beam.

7. The X-ray optical device according to claim 2, wherein: The different diffraction elements are connected to a turret, and wherein the configuration unit is configured to move one of the different diffraction elements into the path of the collimated X-ray beam.

8. The X-ray optical device according to claim 2, wherein: The different diffractive elements include different ellipsoidal monochromators associated with the different wavelengths.

9. The X-ray optical device according to claim 2, wherein: The different diffractive elements also include reduction optics.

10. The X-ray optical device according to claim 2, further comprising a configuration unit for selecting one of the different diffraction elements to interact with the collimated X-ray beam.

11. The X-ray optical device according to claim 1, wherein: The adjustable diffraction unit comprises: Diffractive elements; and A configuration unit is configured to determine a Bragg condition of the diffraction element.

12. The X-ray optical device according to claim 11, wherein The configuration unit is configured to set an optical axis of the collimated X-ray beam, an optical axis of the filtered collimated X-ray beam, and a distance between at least one of the achromatic collimating optics or the achromatic focusing optics and the diffraction element.

13. The X-ray optical device according to claim 12, wherein: The configuration unit is configured to set the optical axis of the collimated X-ray beam by rotating the achromatic collimating optics and to set the optical axis of the filtered collimated X-ray beam by rotating the achromatic focusing optics while maintaining a constant source-to-focus distance.

14. The X-ray optical device according to claim 13, wherein: The adjustable diffraction unit comprises different diffraction elements associated with the different wavelengths, wherein the different diffraction elements comprise the diffraction elements, and wherein the configuration unit is further configured to select one of the diffraction elements to interact with the collimated X-ray beam.

15. A method for steering an input X-ray beam, the method comprising: collimating the input X-ray beam by an achromatic collimating optical device to provide a collimated X-ray beam; receiving the collimated X-ray beam by an adjustable diffraction element while configuring it according to a current configuration associated with a current wavelength selected from among different wavelengths, the current configuration being selected from among different configurations associated with the different wavelengths; filtering the collimated X-ray beam by the adjustable diffraction unit to provide a filtered collimated X-ray beam of the current wavelength; as well as The filtered collimated X-ray beam is focused by achromatic focusing optics to provide a focused filtered X-ray beam.

16. The method according to claim 15, wherein The adjustable diffraction unit comprises different diffraction elements associated with the different wavelengths, and wherein one of the different diffraction elements corresponds to the current configuration.

17. The method according to claim 15, wherein: The adjustable diffraction unit comprises a diffraction element and a configuration unit configured to determine a Bragg condition of the diffraction element, the Bragg condition corresponding to the current configuration.

18. The method according to claim 15, wherein The adjustable diffraction unit comprises different diffraction elements associated with the different wavelengths, and wherein one of the different diffraction elements corresponds to the current configuration.

19. The method according to claim 15, wherein The adjustable diffraction unit comprises a diffraction element and a configuration unit configured to determine a Bragg condition of the diffraction element, the Bragg condition corresponding to the current configuration.

20. An X-ray optical device comprising: a focusing monochromator configured to: (i) receive a non-collimated input X-ray beam, wherein, at a first virtual plane, the non-collimated input X-ray beam forms a first spot; (ii) filter and focus the non-collimated X-ray beam to provide a filtered focused X-ray beam at a current wavelength; and The demagnification achromatic optical device is configured to demagnify the filtered focused X-ray beam of the current wavelength to form a target spot smaller than the first spot at the sample plane.

21. The X-ray optical device according to claim 20, wherein The first light spot is imaged onto a second plane located between the focusing monochromator and the demagnification achromatic optical device, wherein the first plane and the second plane are conjugate planes.

22. The X-ray optical device according to claim 21, wherein An X-ray beam source is located at the first plane.

23. The X-ray optical device of claim 21, further comprising an imaging achromatic optical device configured to image a spot formed by the X-ray beam source onto the first plane.

24. The X-ray optics of claim 20, comprising different focusing monochromators associated with different wavelengths.

25. The X-ray optical device according to claim 20, wherein The focusing monochromator is an ellipsoidal monochromator.

26. The X-ray optical device according to claim 20, wherein The focusing monochromator is an annular monochromator.

27. A method for manipulating X-rays, the method comprising: receiving a non-collimated input X-ray beam by a focusing monochromator, wherein the non-collimated input X-ray beam forms a first spot at a first virtual plane; filtering and focusing the non-collimated X-ray beam by the focusing monochromator to provide a filtered focused X-ray beam of a current wavelength; and The filtered focused X-ray beam of the current wavelength is demagnified by a demagnification achromatic optical device to form a target spot smaller than the first spot at the sample plane.

28. The method according to claim 27, wherein The first light spot is imaged onto a second plane located between the focusing monochromator and the demagnification achromatic optical device, wherein the first plane and the second plane are conjugate planes.

29. The method according to claim 27, wherein An X-ray beam source is located at the first plane.

30. The method of claim 27, further comprising: The light spot formed by the X-ray beam source is imaged onto the first plane by an imaging achromatic optical device.

Images