High brightness primary x-ray source for online XPS and XRF metrology

Abstract

A method for evaluating a sample, the method comprising: (a) irradiating a jet of liquid metal that forms an alloy with aluminum with an electron beam to provide a first X-ray beam; (b) spectrally filtering the first X-ray beam by a filtering unit to provide a second X-ray beam; (c) irradiating the sample with a second X-ray beam; and (e) detecting X-ray radiation emitted from the sample due to the irradiation of the sample.

Description

[0001] Cross-references

[0002] This application claims priority to U.S. Provisional Patent No. 63 / 376,770 filed on September 22, 2022, which is incorporated herein by reference. Background Art

[0003] The most commonly used X-ray energy in XPS is aluminum Ka (1486.7 eV), which is usually transmitted through a monochromator and focused onto the wafer surface to narrow the natural line width of the emission line for chemical state identification.

[0004] The maximum kinetic energy of photoelectrons produced by aluminum Ka radiation will be about 1486 eV, thus limiting the analysis depth to about 10 m, while also providing a limited range of secondary X-ray fluorescence lines that can be detected simultaneously and used as an independent input for the total dose to the material being analyzed.

[0005] The overall analytical depth can often be increased by utilizing high intensity, high energy primary X-rays, which also tends to expand the range of excited fluorescence X-ray lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portions of the specification. However, the invention as to its organization and method of operation, together with objects, features, and advantages thereof, will be best understood from the following detailed description when read in connection with the accompanying drawings, in which:

[0007] Figure 1 A phase diagram is shown;

[0008] Figure 2 An example of generating a high brightness X-RAY beam is shown;

[0009] Figure 3 An example of generating a high brightness X-RAY beam is shown;

[0010] Figure 4 An example of a quasi-continuously tunable single wavelength X-ray source is shown; and

[0011] Figure 5 An example of a method is shown. DETAILED DESCRIPTION

[0012] In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be appreciated 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 are not described in detail in order not to obscure the present invention.

[0013] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portions of the specification. However, the invention as to its organization and method of operation, together with objects, features and advantages thereof, will be best understood from the following detailed description when read in connection with the accompanying drawings.

[0014] It will be understood that for simplicity and clarity of illustration, the elements shown in the figures are not necessarily drawn to scale. For example, for clarity, the size of some elements may be exaggerated relative to other elements. In addition, where deemed appropriate, reference numerals may be repeated in the drawings to indicate corresponding or similar elements.

[0015] Since the embodiments of the present invention can be implemented to a large extent using optoelectronic components known to those skilled in the art, in order to understand and appreciate the basic concepts of the present invention and in order not to obscure or deviate from the content conveyed by the present invention, the details will not be explained in more depth except to the extent deemed necessary as described above.

[0016] Any reference to a method in this specification should be applicable, mutatis mutandis, to a system capable of performing the method.

[0017] Any reference to a system in this specification shall apply, mutatis mutandis, to the method performed by the system.

[0018] A system for evaluating a sample is provided, the system comprising (a) a source of a liquid metal jet alloyed with aluminum; (b) an electron beam source configured with an electron optics configured to irradiate the liquid metal jet alloyed with aluminum with an electron beam to provide a first X-ray beam; (c) a filtering unit configured to spectrally filter the first X-ray beam to provide a second X-ray beam; (d) an electron optics configured to irradiate the sample with the second X-ray beam; and (e) a detector configured to detect X-ray radiation emitted from the sample as a result of the irradiation of the sample.

[0019] A high brightness primary X-ray source for on-line XPS and XRF metrology is provided, which is capable of producing an X-ray beam in the range of about 1 keV and above so as to enable wafer composition analysis and thickness metrology using medium and high energy X-ray beams.

[0020] An X-ray source is provided that can (eg, simultaneously) generate high-brightness aluminum Ka (hv=1486.7 eV) and continuous high-energy radiation generated by an aluminum alloy (eg, aluminum-gallium, aluminum-indium, or other low-melting-point metal combinations).

[0021] The continuous radiation generated by the second, third and fourth order Bragg reflection selections at photon energies of 2973.4 eV, 4460.1 eV and 5946.8 eV, respectively, can be transmitted and focused by a focusing quartz monochromator, that is, four or more different high brightness / high intensity X-ray energies are generated and selected that can be focused onto the wafer.

[0022] When using a combination of XPS and XRF to analyze the material composition of small targets, the primary and secondary X-ray radiation provide distinct and independent material information.

[0023] In order to increase the throughput while reducing the measurement spot size, as required for on-line XPS / XRF metrology, a high-brightness X-ray source combined with an efficient monochromator is required.

[0024] A brighter X-ray source will provide a smaller divergence angle and concentrate the high flux into a smaller spot. It will also allow the use of a smaller monochromator, reducing the risk of crystal misalignment and saving costs.

[0025] Smaller monochromators will likely provide better energy resolution and improve spot size while being less sensitive to slight misalignment errors. Using a monochromator will ensure that the final X-ray linewidth at the target is less than 0.5 eV energy width, thus achieving sufficient photoelectron energy resolution to resolve various bonding states of elements at excitation X-ray energies less than 1500 eV. The higher primary X-ray brightness allows the active area of ​​the monochromator crystal to be reduced by a factor of 2, and if the X-ray flux of the X-ray source is increased by a factor of 10, the overall improvement in spot size and t-yield can still be 5 times.

[0026] Additionally, the availability of high-energy X-rays from higher Bragg diffraction orders will also facilitate tuning of the photon energy of XPS and XRF to provide optimal excitation conditions for material characterization (composition, contamination, and thickness), depending on the thickness and composition of the material.

[0027] The excitation of the primary X-ray beam can be accomplished by:

[0028] a. Intense electron beam irradiation of liquid, solid or gas jet.

[0029] b. The electron beam source can be a focused conventional LaB6 electron source or equivalent.

[0030] c. The electron beam can be generated by a photocathode source illuminated by a high brightness focused light / laser source of a suitable wavelength instead of a conventional electron source.

[0031] d. Light-assisted X-ray emission from the target material produced by the synergistic effect of the electron beam.

[0032] The excitation of the primary source X-rays can also be achieved by a focused high intensity laser beam. The preferred excitation mode is continuous X-ray beam generation, although operation of a pulsed X-ray source is also contemplated with appropriate coordination of the metrology system.

[0033] An aluminum-gallium liquid metal alloy is provided as an X-ray target for generating high-brightness aluminum Ka (1486.7 eV) and gallium Ka (9251.67 eV).

[0034] Aluminum-gallium alloys (see Figure 1 ) phase diagram indicates that aluminum-gallium alloys are in the liquid phase slightly above room temperature and have different stoichiometric ratios.

[0035] Interestingly, aluminum-gallium liquid metal alloys have been used as catalysts for decomposing water to produce hydrogen, and their properties have been characterized (Y. Yu et al., Jeffrey T. Ziebarth et al.).

[0036] In Al x Gai- x At a mass ratio of (x=10, 20, 30, 40, 50), aluminum is evenly distributed in the liquid metal when the temperature is higher than the ambient temperature.

[0037] In liquid Al-Ga alloys, the presence of Ga inhibits the formation of an Al2O3 passivation layer, whereas this is not the case in solid Al. 70 Ga 30 and Al 80 Ga 20 , the elemental distribution of aluminum and gallium is not uniform, and trace amounts of Al2O3 are detected. The brightness of aluminum Ka produced by an aluminum-gallium liquid metal jet (or other suitable liquid metal jet alloyed with aluminum) is expected to be at least one order of magnitude higher than that of conventional solid targets. Using a monochromator to efficiently collect large solid angles from such a source, the flux falling on the measurement target is expected to be 1 to 2 orders of magnitude higher than that of a solid aluminum target at less than about 50μm x 50μm.

[0038] Aluminum-gallium alloys are in liquid phase at high temperatures and can be used as X-ray targets in the form of a jet. Therefore, when a high-power, high-brightness electron beam is directed and incident on a fast-moving jet of liquid metal alloy, a bright aluminum Kα and gallium Kα X-ray source can be generated.

[0039] The system can use liquid metal aluminum-gallium alloy as an X-ray source anode to produce high brightness aluminum Kα and gallium Kα for XPS and XRF combined systems. In AlxGa100-x, the weight x can range from x<60 to x=0.

[0040] Bright X-ray sources using aluminum-gallium alloys can be integrated into XPS and XRF online metrology systems (as disclosed in US9,240,254, incorporated herein by reference), and used with a monochromator to produce high brightness monochromated aluminum Kα (1486.7 eV) and high harmonic photon energies up to the fourth order (2973.4 eV, 4460.1 eV, and 5946.8 eV) for high energy XPS and XRF applications, while also producing gallium Kα (9251.67 eV). Gallium Kα can be used with different monochromators to produce alternative high brightness monochromated X-rays for material composition analysis using XPS or XRF, as well as XPS XRF combined methods.

[0041] Aluminum-gallium and aluminum-indium alloys or other suitable metal alloys are used as X-ray targets. When excited by the high-energy and high-brightness electron beam generated by the photocathode, they produce unique aluminum Kα and indium Kα lines, which are superimposed on the continuous X-ray spectrum of the so-called Bremsstrahlung background.

[0042] In general, bremsstrahlung is most efficiently generated when energetic small particles interact with high atomic number elements. Specifically, in the context of the present disclosure, the bremsstrahlung generated from indium, tin, or gallium will be much higher than aluminum, and its yield increases with increasing electron energy and electron beam power. Due to the rapid heat dissipation of the LMJ target, the source can withstand significantly higher electron source energies and powers, thereby generating higher bremsstrahlung. The bremsstrahlung can be selected by a monochromator to provide high energy X-rays suitable for XRF and XPS performed at increased analytical depths.

[0043] A bright electron beam is a prerequisite for producing a high-brightness X-ray beam from a liquid metal jet, although it is not a guaranteed condition.

[0044] The coupling of a bright electron beam source with a liquid metal jet anode will enhance the performance of X-rays. It is known to those skilled in the art that increasing the electron beam power input to the X-ray anode will increase the X-ray intensity.

[0045] However, in order to produce high-brightness X-rays, a high-brightness electron source with high power density and high brightness needs to be paired with an anode target. It is known that simply increasing the brightness and power density of the electron beam will lead to catastrophic failure of X-ray sources using solid anode X-ray targets. In the case of liquid metal targets, due to the circulation and replenishment characteristics of the liquid metal jet, higher electron beam power and power density can be used to produce high-brightness X-ray beams. Among X-ray sources, the most commonly used electron source consists of a LaBe cathode and electron focusing optics.

[0046] However, another approach is to generate a high brightness and high power density electron beam for a high brightness liquid metal jet X-ray source by using a laser driven photocathode for which the inherent emission spot size is determined by the size of the illumination source (as disclosed in US PA No. 63 / 365,414, incorporated herein by reference).

[0047] Figure 2 A schematic diagram of a high brightness electron beam generated by a photocathode operating in transmission mode to generate a first X-ray beam using a disclosed anode material is shown. After coupling with a monochromator, the first X-ray beam is converted into a second X-ray beam, which is used as an excitation source for XPS and XRF.

[0048] exist Figure 2 In the embodiment, the transmission X-ray source includes a radiation source, such as a photon beam source 20 (such as but not limited to a laser), which is configured to direct radiation (such as a beam 11) to a transparent substrate 30, which mechanically supports a photocathode 40. The beam 11 is incident on one side of the photocathode 40, causing electrons to be emitted from the opposite side of the photocathode to form an electron beam 12. The electron beam 12 is attracted to a control grid 50 (which is biased relative to the photocathode 40 by a bias circuit 70, which may determine the energy of the electrons emitted from the control grid), and then passes through a liquid metal jet (LMJ) to provide a first X-ray beam 13, which is incident on a monochromator 80 to provide a second X-ray beam 13A, which irradiates a sample 90, resulting in the generation of fluorescent X-rays 14 that can be detected by a detector 88.

[0049] exist Figure 3 In the embodiment, the transmission X-ray source includes a radiation source, such as a photon beam source 20 (such as but not limited to a laser), which is configured to direct radiation (such as a light beam 11) to a photocathode 40. The photocathode 40 is supported by a substrate 31. The light beam 11 is incident on one side of the photocathode 40, causing electrons to be emitted from the same side to form an electron beam 12. The electron beam 12 is attracted to a control grid 50 (which is biased relative to the photocathode 40 by a bias circuit 70, which may determine the energy of the electrons emitted from the control grid), and then passes through a liquid metal jet (LMJ) to provide a first X-ray beam 13, which is incident on a monochromator 80 to provide a second X-ray beam 13A, which irradiates a sample 90, resulting in the generation of fluorescent X-rays 14 that can be detected by a detector 88.

[0050] Figure 3The X-ray source can be replaced by a gas chamber or a liquid jet to provide a continuous X-ray spectrum covering a wide range of X-ray energies, thereby providing a first X-ray beam 13A, which is incident on the monochromator 80 to provide a second X-ray beam 13A, which irradiates the sample 90, resulting in the generation of fluorescent X-rays 14 that can be detected by the detector 88.

[0051] exist Figure 2 and Figure 3 In the present invention, the electron beam 12 is of high quality and can also be shaped and focused to a very small spot size using electron beam optics (located between the photocathode and the X-ray material).

[0052] exist Figure 2 and Figure 3 In the embodiment, an electron optical device may be provided, which may include at least some components of the electron beam column, such as one or more apertures and / or one or more deflectors and / or one or more scanning coils and / or one or more electromagnetic lenses and / or one or more magnetic lenses and / or one or more detectors.

[0053] In addition, any suitable X-ray optics and monochromators (e.g., an X-ray beam collimator in combination with a planar monochromator and subsequent focusing optics) may also be used with the high brightness liquid metal jet disclosed herein. The emitted photoelectrons will be collected by a focusing electron lens and directed to an energy analyzer in XPS, while fluorescent X-rays will also be generated by the material and collected by EDS or WDS in XRF.

[0054] The high brightness, high intensity continuous radiation produced by LMJ X-rays combined with suitable non-dispersive X-ray focusing optics and the X-ray energy selection by a movable (or angle-adjustable) monochromator crystal can provide a quasi-continuously adjustable single wavelength X-ray source for XPS and XRF at the analysis site. If a fixed crystal focusing monochromator is used to transmit the X-ray beam to the wafer, multiple different diffraction orders with increasing energies can be transmitted and focused.

[0055] Figure 4 Schematic diagram of a quasi-continuously tunable single wavelength X-ray source, wherein single wavelength tuning is achieved by rotating a planar monochromator 100 and then adjusting two polycapillaries or other suitable reflective achromatic collimating and focusing optics 101 and 102 to satisfy the Bragg condition.

[0056] The wavelength tuning of the continuous X-ray is achieved by rotating the crystal relative to the incident X-ray, which is collimated by the first polycapillary or reflective optical device, and the reflected light that meets the Bragg angle of the crystal monochromator is focused on the sample as the excitation source for XPS and XRF. The first X-ray beam 13 is incident on the crystal 100, and the crystal diffracts the second X-ray beam 13A incident on the sample 90. The wavelength of the second X-ray beam follows the equation n = 2dsin(θ').

[0057] Figure 4 A quasi-continuously tunable single wavelength X-ray source is also shown, where single wavelength tuning is achieved by translating a planar monochromator followed by adjusting two polycapillary or reflective collimating and focusing optics to meet the Bragg condition. Single X-ray wavelength selection from a broad spectrum LMJ source is achieved by translating a crystal monochromator followed by adjusting the first polycapillary (or reflective) optic and the second polycapillary (or reflective) optic to meet the Bragg condition. and ) will provide great flexibility in sample detection depth in XPS and XRF.

[0058] According to our calculations based on a published scientific paper (Malte Wansleben et al., Journal of Analytical Atomic Spectrometry, 2019), when an aluminum-gallium liquid metal anode is coupled to a sufficiently strong electron beam source, the X-ray brightness it produces is expected to be at least an order of magnitude higher than that of a solid target anode X-ray source.

[0059] The system enables smaller measurement target capabilities in online XPS (and XRF) without sacrificing signal-to-noise ratio and XPS energy resolution. Due to the increased brightness of the light source, signal contamination outside the measurement spot will be suppressed, thereby improving the accuracy and precision of composition measurement. In addition, this method will fully utilize the advantages of the monochromator to transmit and focus the generated high-energy X-rays onto the wafer through second-order and higher-order Bragg reflections. This in turn expands the online metrology applications of XPS / XRF in different application scenarios, that is, while expanding the depth of photoelectron escape analysis, it is combined with a wider range of fluorescent X-rays that can be detected simultaneously via XRF through the same tool.

[0060] Higher X-ray source brightness can be exploited to use smaller monochromators, reducing the risk of crystal misalignment and also saving costs. Smaller monochromators may provide better energy resolution and improve spot size while being less sensitive to slight misalignment errors.

[0061] Furthermore, it is very beneficial to use a single X-ray source to perform XPS and XRF measurements under different conditions, rather than using two different X-ray sources.

[0062] The high brightness X-ray source can produce aluminum Ka, bremsstrahlung, and gallium Ka (or other suitable liquid jet material radiation) using the same electron beam power supply and the same X-ray source.

[0063] The proposed high brightness X-ray source is capable of providing access to a continuously tunable or several different multiples of a design wavelength (e.g., aluminum Kα X-ray energy), which provides the following capabilities:

[0064] a. Increase or decrease the XPS analysis depth, and

[0065] b. Increase or decrease the amount of characteristic fluorescent X-rays produced and available for detection.

[0066] Figure 5 An example of a method 200 for evaluating a sample is shown.

[0067] According to an embodiment, method 200 includes step 210 of irradiating a liquid metal jet alloyed with aluminum with an electron beam to provide a first X-ray beam.

[0068] According to an embodiment, step 210 is followed by step 220 of spectrally filtering the first X-ray beam by a filtering unit to provide a second X-ray beam.

[0069] According to an embodiment, step 220 is followed by step 230 of irradiating the sample with a second X-ray beam.

[0070] According to an embodiment, step 230 is followed by step 240 of detecting X-ray radiation emitted from the sample as a result of irradiating the sample.

[0071] According to an embodiment, the electron beam is a continuous electron beam.

[0072] According to an embodiment, the electron beam in the method is a pulsed electron beam.

[0073] According to an embodiment, the second X-rays include photoelectrons generated by aluminum Ka radiation energy of approximately 1486 electron volts.

[0074] According to an embodiment, the second X-ray includes: (i) a second order Bragg reflection with an energy of approximately 2973.4 electron volts, (ii) a third order Bragg reflection with an energy of approximately 4460.1 electron volts, and (iii) a fourth order Bragg reflection with an energy of approximately 5946.8 electron volts.

[0075] According to an embodiment, the second X-rays include photoelectrons generated by gallium La radiation energy of approximately 1097.92 electron volts.

[0076] According to an embodiment, the second X-rays include photoelectrons generated by gallium Ka radiation energy of approximately 9251.74 electron volts.

[0077] According to an embodiment, the liquid metal jet alloyed with aluminum is an aluminum gallium alloy.

[0078] According to an embodiment, the liquid metal jet alloyed with aluminum is different from an aluminum-gallium alloy.

[0079] According to an embodiment, the method comprises changing a parameter of the second X-ray beam, for example, wavelength, between one measurement (at least one iteration of steps 210 , 220 , 230 and 240 ) and another measurement (at least one other iteration of steps 210 , 220 , 230 and 240 ), changing the concentration ratio between aluminum and another metal in the jet of liquid metal alloyed with aluminum, etc. This is illustrated by step 250 .

[0080] According to an embodiment, the method comprises setting the second bandwidth by setting an angular relationship between the first X-ray beam and a crystal of the filtering unit.

[0081] According to an embodiment, the spectral filtering is performed by a monochromator.

[0082] According to an embodiment, the spectral filtering is performed by a crystal.

[0083] Depending on the embodiment, the spectral filtering is performed by a single or multiple monochromators.

[0084] According to an embodiment, the method comprises performing a set of X-ray Photoelectron Spectroscopy (XPS) measurements, varying at least one parameter of the second X-ray beam, and performing a set of X-ray Fluorescence (XRF) measurements.

[0085] 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 forth in the appended claims.

[0086] Any reference to “comprising”, “having” or “including” shall apply mutatis mutandis to “consisting of” and / or, mutatis mutandis to “consisting essentially of”.

[0087] Furthermore, terms such as "front", "rear", "upper", "lower", "above", "below", etc., used in the specification and claims (if any) are used for descriptive purposes and are not necessarily intended to describe fixed relative positions. It is understood that these terms are interchangeable under appropriate circumstances so that, for example, the embodiments of the invention described herein are capable of operation in other orientations than shown or described herein.

[0088] Any arrangement of components to achieve the same functionality can be effectively considered "associated" to achieve the desired functionality. Therefore, any two components combined to achieve a specific functionality herein can be considered "associated" with each other to achieve the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered "operably connected" or "operably coupled" to each other to achieve the desired functionality.

[0089] In addition, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations may be combined into a single operation, a single operation may be decomposed into multiple additional operations, and these operations may be performed at least partially overlapping in time. In addition, other embodiments may include multiple instances of specific operations, and the order of operations may be different in various other embodiments.

[0090] Furthermore, for example, in one embodiment, the examples shown may be implemented as circuits located on a single integrated circuit or within the same device. Alternatively, these examples may be implemented as any number of separate integrated circuits or separate devices that are interconnected in an appropriate manner.

[0091] However, other modifications, changes, and alternatives are possible. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

[0092] In the claims, any reference numerals placed in parentheses shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of other elements or steps than those listed in the claims. In addition, the terms "a" or "an" as used herein are defined as one or more. Similarly, the use of introductory phrases such as "at least one" and "one or more" in the claims shall not be construed as implying that the introduction of another claim element by the indefinite article "a" or "an" will limit any particular claim containing such introduced claim element 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 an indefinite article such as "a" or "an". The same applies to the use of definite articles. Unless otherwise specified, terms such as "first" and "second" are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate a priority of such elements in time or other aspects. The mere fact that certain measures are listed in mutually different claims does not mean that a combination of these measures cannot be effectively used.

[0093] Although certain features of the present invention have been shown and described herein, many modifications, substitutions, changes and equivalents will be apparent to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the present invention.

[0094] The described implementation of the alloyed liquid metal jet X-ray source can be used as an example of a broadband X-ray source, but other X-ray sources providing a broadband continuous X-ray spectrum can be considered in conjunction with the present invention. This can be an X-ray source using a gas or liquid jet and excited by an electron beam.

Claims

1. A method for evaluating a sample, the method comprising: irradiating a liquid metal jet alloyed with aluminum with an electron beam, a laser beam, or a combination of a laser beam and an electron beam, or a plurality of laser beams to provide a first X-ray beam; spectrally filtering the first X-ray beam by a filtering unit to provide a second X-ray beam; irradiating the sample with the second X-ray beam; as well as X-ray radiation emitted from the sample as a result of the sample being irradiated is detected.

2. A method for evaluating a sample, the method comprising: Irradiating a gas or liquid jet or medium providing an intense X-ray continuum with a wide energy range with an electron beam, a laser beam, or a combination of a laser beam and an electron beam, or a plurality of laser beams to produce a first X-ray beam; spectrally filtering the first X-ray beam by a filtering unit to provide a second X-ray beam; irradiating the sample with the second X-ray beam; as well as X-ray radiation emitted from the sample as a result of the sample being irradiated is detected.

3. The method according to claim 1, wherein: The electron beam is a continuous electron beam.

4. The method according to claim 1, wherein: The electron beam is a pulsed electron beam.

5. The method according to claim 1, wherein: The laser beam is a continuous laser beam.

6. The method according to claim 1, wherein: The electron beam is a pulsed laser beam.

7. The method according to claim 1, wherein: The laser beam has a wavelength between 100 nm and 5 um.

8. The method according to claim 1, wherein: The liquid metal jet target generates a wide spectrum X-ray source with an X-ray energy range of 1 keV to 10 keV.

9. The method according to claim 1, wherein: The second X-ray beam includes photoelectrons generated by aluminum Ka radiation energy of approximately 1486.7 electron volts.

10. The method according to claim 1, wherein: The second X-ray beam includes (i) a second order Bragg reflection having an energy of approximately 2973.4 electron volts, (ii) a third order Bragg reflection having an energy of approximately 4460.1 electron volts, and (iii) a fourth order Bragg reflection having an energy of approximately 5946.8 electron volts.

11. The method according to claim 1, wherein: The second X-ray beam includes photoelectrons generated by gallium La radiation energy equivalent to about 1097.92 electron volts.

12. The method according to claim 1, wherein: The second X-ray beam includes photoelectrons generated by gallium Ka radiation energy equivalent to about 9251.74 electron volts.

13. The method according to claim 1, wherein: The liquid metal jet alloyed with aluminum is an aluminum-gallium alloy.

14. The method according to claim 1, wherein: The liquid metal jet alloyed with aluminum is different from the aluminum gallium alloy.

15. The method of claim 1, comprising varying the concentration ratio between aluminum and another metal in the jet of liquid metal alloyed with aluminum from one measurement to another.

16. The method of claim 1, comprising setting the second bandwidth by setting an angular relationship between the first X-ray beam and a crystal of a filtering unit.

17. The method according to claim 1, wherein: The spectral filtering is performed by a monochromator.

18. The method according to claim 1, wherein: The spectral filtering is performed by a crystal.

19. The method according to claim 1, wherein: The spectral filtering is performed by single or multiple monochromators.

20. The method of claim 1, comprising performing a set of X-ray photoelectron spectroscopy (XPS) measurements, varying at least one parameter of the second X-ray beam, and performing a set of X-ray fluorescence (XRF) measurements.

21. A system for evaluating a sample, the system comprising: a source of a jet of liquid metal to alloy with the aluminum; an electron beam source configured with electron optics configured to irradiate the jet of liquid metal alloyed with aluminum with an electron beam to provide a first X-ray beam; a filtering unit configured to perform spectral filtering on the first X-ray beam to provide a second X-ray beam; electron optics configured to irradiate the sample with the second X-ray beam; as well as A detector is configured to detect X-ray radiation emitted from the sample as a result of the sample being irradiated.

22. The system of claim 21, wherein: The second X-ray beam includes photoelectrons generated by aluminum Ka radiation energy of approximately 1486 electron volts.

23. The system of claim 21, wherein: The second X-ray beam includes (i) a second order Bragg reflection having an energy of approximately 2973.4 electron volts, (ii) a third order Bragg reflection having an energy of approximately 4460.1 electron volts, and (iii) a fourth order Bragg reflection having an energy of approximately 5946.8 electron volts.

24. The system of claim 21, wherein: The second X-ray beam includes photoelectrons generated by gallium La radiation energy of approximately 1097.92 electron volts.

25. The system of claim 21, wherein: The second X-ray beam includes photoelectrons generated by gallium Ka radiation energy of approximately 9251.74 electron volts.

26. The system of claim 21, wherein: The liquid metal jet alloyed with aluminum is an aluminum-gallium alloy.

27. The system of claim 21, wherein: The jet of liquid metal alloyed with aluminum is different from the aluminum gallium alloy.

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