Notch filter for high throughput x-ray photon spectroscopy

Abstract

Disclosed herein is a sample characterization system, the sample characterization system comprising: a characterization tool configured to generate an electron beam directed toward a sample under test; an X-ray photon energy dispersion detector (EDX) configured to collect X-ray photons emitted from the sample under test; and a filter assembly positioned in the characterization tool between the sample under test and the EDX, the filter assembly comprising a band elimination filter, the band elimination filter is configured to allow information-carrying X-ray photons having a predetermined energy range to transmit therethrough and to prevent irrelevant photons having an energy range different from the predetermined energy range from reaching the EDX, whereby, compared to a sample characterization system without the filter assembly, X-ray photons having an energy range different from the predetermined energy range are not transmitted through the band elimination filter. The ratio between the count of information-carrying X-ray photons reaching the EDX and the total photon count reaching the EDX is increased.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the manufacturing and metrology of samples. BACKGROUND

[0002] The continuing trend of semiconductor device scaling in conjunction with the integration of multiple elements therein has created a need for manufacturing and metrology techniques that operate at the nanometer scale. This need has become particularly pronounced in the field of mass production as semiconductor devices continue to employ complex geometries, such as 3D chips.

[0003] One of the primary methods for determining sample composition during a manufacturing process includes utilizing X-ray spectroscopy with an energy dispersive detector (EDX). This is often implemented with a system such as a scanning electron microscope equipped with an EDX detector. However, the efficiency of such measurements can be hindered by the count rate of the EDX detector.

[0004] Accordingly, there is a need in the art for systems and methods that facilitate fast and reliable composition analysis. SUMMARY

[0005] According to some embodiments of the present disclosure, aspects of the present disclosure relate to the manufacturing and metrology of samples.

[0006] More specifically, but not exclusively, according to some embodiments of the present disclosure, aspects of the present disclosure relate to the manufacturing and characterization of samples such as wafers, photoresists, semiconductor devices, and / or components thereof.

[0007] Accordingly, according to an aspect of some embodiments, there is provided a sample characterization system, comprising:

[0008] (a) a characterization tool configured to generate an electron beam directed toward a sample under test;

[0009] (b) an X-ray photon energy dispersive detector (EDX) configured to collect X-ray photons emitted from the sample under test;

[0010] (c) a filter assembly positioned in the characterization tool between the tested sample and the EDX. The filter assembly includes a band-stop filter configured to allow information-carrying X-ray photons having a predetermined energy range to transmit therethrough, while preventing irrelevant photons having an energy range different from the predetermined energy range from reaching the EDX / attenuating irrelevant photons having an energy range different from the predetermined energy range from reaching the EDX. In this way, the ratio between the count of information-carrying X-ray photons reaching the EDX and the total photon count reaching the EDX is increased compared to a sample characterization system without the filter assembly.

[0011] According to some embodiments, the filter assembly can further include an electron filter configured to attenuate backscattered electrons emitted from the tested sample. According to some embodiments, the electron filter also absorbs / attenuates photons. According to some embodiments, the electron filter is configured to attenuate parasitic photons to a greater extent than the information-carrying electrons. According to some embodiments, in addition to or instead of the electron filter, the filter assembly can include a deflector configured to deflect electrons away from the filter assembly.

[0012] According to some embodiments, the filter assembly can further include one or more additional band-stop filters. According to some embodiments, each of the one or more additional band-stop filters is configured to filter out / absorb / attenuate X-ray photons having a different respective predetermined energy of X-ray photons.

[0013] According to some embodiments, at least a portion of the band-stop filter can be made of or include a plurality of thin films. According to some embodiments, each of the plurality of thin films has a thickness in a range of 50 nm to 5 pm, in a range of 500 nm to 5 pm, or in a range of 1000 nm to 5 pm. Each possibility is a separate embodiment. According to some embodiments, at least a portion of the plurality of thin films comprises: Hf, Al, BN, TiN, Si3N4, V, Ti, Teflon, Mn, Cr, Fe, Al2O3, or any combination thereof. Each possibility is a separate embodiment.

[0014] According to some embodiments, at least a portion of the plurality of thin films comprises:

[0015] a. Mylar and Hf,

[0016] b. Mylar and Fe,

[0017] c. Mylar and Al2O3, or

[0018] d. Al and Mg.

[0019] According to some embodiments, the band-stop filter is a notch filter.

[0020] According to some embodiments, the filter assembly or parts thereof are replaceable in situ. According to some embodiments, the predetermined energy range depends on the material from which the filter is made, thereby allowing adjusting its value.

[0021] According to some embodiments, the ratio is increased by a factor of 8 or more.

[0022] According to some embodiments, the predetermined energy range is about 50 eV to 15 KeV. According to some embodiments, the predetermined energy range is about 50 eV to 30 KeV.

[0023] According to some embodiments, the characterization tool comprises an electron microprobe, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning TEM (STEM). Each possibility is a separate embodiment.

[0024] According to some embodiments, there is provided a method for filtering photons by energy, the method comprising:

[0025] (a) directing a primary electron beam onto a tested sample, thereby initiating emission of X-ray photons and electrons from the tested sample;

[0026] (b) attenuating X-ray photons having energies different from a predetermined energy range of information-carrying X-ray photons by using a band-stop filter positioned between the tested sample and the EDX;

[0027] (c) detecting the information-carrying X-ray photons by the EDX, whereby, as compared to a sample characterization system without the filter assembly, a ratio between a count of information-carrying X-ray photons reaching the EDX and a total photon count reaching the EDX is increased; and

[0028] (d) outputting a signal indicative of the information-carrying X-ray photons detected by the EDX.

[0029] According to some embodiments, the method further comprises attenuating backscattered electrons and / or secondary electrons emitted from the tested sample using an electron filter. Additionally or alternatively, the method can further comprise deflecting backscattered and / or secondary electrons away from the filter assembly. According to some embodiments, the electron filter can further attenuate a portion of the emitted photons. According to some embodiments, the electron filter can be configured to absorb / attenuate parasitic electrons while allowing information-carrying photons to transmit therethrough.

[0030] According to some embodiments, a filter assembly for filtering photons by energy is provided. According to some embodiments, the filter assembly comprises a bandpass filter configured to allow information carrying X-ray photons having a predetermined energy range to transmit therethrough and prevent / inhibit irrelevant photons from reaching an energy dispersive detector (EDX). In this manner, the ratio between the count of information carrying X-ray photons reaching the EDX and the total photon count reaching the EDX is increased as compared to a sample characterization system without the filter assembly.

[0031] According to some embodiments, at least a portion of the bandpass filter is made of or comprises a plurality of thin films having a thickness of about 50 nm to 5 pm. According to some embodiments, at least a portion of the plurality of thin films comprises a material selected from: Hf, Al, BN, TiN, Si3N4, V, Ti, Teflon, Mn, Cr, Fe, or AI2O3. Each possibility is a separate embodiment.

[0032] According to some embodiments, the ratio of counts is increased by a factor of 8 or more.

[0033] According to some embodiments, the filter assembly further comprises an electronic filter configured to attenuate backscattered electrons and / or secondary electrons emitted from the tested sample. Additionally or alternatively, the filter assembly comprises a deflector configured to deflect electrons away from the filter assembly.

[0034] According to some embodiments, at least a portion of the plurality of thin films comprises:

[0035] a. Mylar and Hf,

[0036] b. Mylar and Fe,

[0037] c. Mylar and AI2O3, or

[0038] d. Al and Mg.

[0039] According to some embodiments, the predetermined energy is in the range of 50 eV to 15 KeV. According to some embodiments, the predetermined energy is in the range of 50 eV to 30 KeV.

[0040] Certain embodiments of the present disclosure can include some, all or none of the advantages mentioned above. One or more other technical advantages can be readily apparent to those skilled in the art in light of the attached drawings, descriptions, and claims. Moreover, while specific advantages have been enumerated above, various embodiments can include all, some or none of the enumerated advantages.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In case of conflict, the patent specification, including definitions, controls. As used herein, the indefinite articles "a" and "an" mean "at least one" or "one or more," unless context clearly indicates otherwise. BRIEF DESCRIPTION OF DRAWINGS

[0042] Some embodiments of the present disclosure are described herein with reference to the accompanying drawings. The description is presented in conjunction with the drawings, which are by way of illustration only and not intended to be limiting of the disclosure. The description throughout this application is made by way of example in Figure One to practice some embodiments. The drawings are for purposes of illustration only and are not intended to be an exhaustive description of the architecture of the embodiments of the present disclosure. The drawings are not drawn to scale unless otherwise indicated. Furthermore, two or more specific embodiments of a drawing can be combined to illustrate one or more aspects of the disclosure. Specifically, some objects of the drawings can be greatly exaggerated relative to other objects in the same drawing.

[0043] In the drawings:

[0044] Figure 1 A block diagram of a system for characterizing a sample according to some embodiments is presented;

[0045] Figures 2A-2C A schematic of a cross-sectional side view of a filter system for filtering photons by energy according to some embodiments is presented;

[0046] Figure 3A A flowchart of a method for filtering photons by energy according to some embodiments is presented;

[0047] Figure 3B A schematic of the working principle of a method and system for filtering photons by energy according to some embodiments is presented; and

[0048] Figure 3C A schematic of a graph of transmittance as a function of photon energy according to some embodiments is presented. DETAILED DESCRIPTION

[0049] The principles, uses and implementations of the teachings herein can be better understood with reference to the accompanying description and figures. Upon careful consideration of the present disclosure and the accompanying drawings, one skilled in the art will be able to implement the teachings of the present disclosure without making undue efforts or experiments.

[0050] According to an aspect of some embodiments, there is provided a system for characterizing a sample. Figure 1A block diagram of one example of such a system, system 100, in accordance with some embodiments is presented. System 100 includes a characterization tool 102.

[0051] According to some embodiments, characterization tool 102 can include an electron microprobe, a scanning electron microscope (SEM), a transmission electron microscope (TEM), a scanning TEM (STEM), or the like. Each possibility is a separate embodiment.

[0052] According to some embodiments, characterization tool 102 includes a stage 120 configured to house a sample 122. As a non-limiting example, sample 122 can include a specimen under inspection in the form of a patterned wafer, an unpatterned wafer, a semiconductor device or component thereof, or the like.

[0053] According to some embodiments, stage 120 can be movable. According to some embodiments, stage 120 can be detachable.

[0054] According to some embodiments, characterization tool 102 is configured to generate an electron beam directed toward sample 122 and collect data from sample 122. More specifically, in some embodiments, characterization tool 102 includes an electron beam (e-beam) source 104 configured to generate an e-beam (i.e., a primary e-beam) directed toward sample 122. According to some embodiments, e-beam source 104 can include an electron gun. As a non-limiting example, in cases where characterization tool 102 includes a SEM, the e-beam generated by e-beam source 104 can have an acceleration voltage in a range of about 1 KV to about 30 KV.

[0055] According to some embodiments, characterization tool 102 includes an electron detector 106 configured to detect electrons emitted from sample 122 as a result of the e-beam impinging into sample 122. In some embodiments, the electrons emitted from sample 122 can include secondary electrons and / or backscattered electrons emitted therefrom.

[0056] According to some embodiments, characterization tool 102 includes an X-ray detector 108. In some embodiments, X-ray detector 108 includes an energy dispersive detector (i.e., an EDX detector). In some embodiments, X-ray detector 108 is configured to detect X-ray photons emitted from sample 122 as a result of the e-beam impinging into sample 122.

[0057] In some embodiments, characterization tool 102 can optionally include one or more additional detectors, such as but not limited to optical detectors, electrostatic lenses and / or deflectors, magnetic lenses and / or deflectors, or the like, or any combination thereof (not shown).

[0058] In some embodiments, characterization tool 102 can optionally include one or more vacuum pumps (not depicted). In some embodiments, the one or more vacuum pumps can be configured to maintain a vacuum environment within characterization tool 102. As a non-limiting example, characterization tool 102 can operate in an ultra-high vacuum state.

[0059] According to some embodiments, and as depicted in FIG. 1, characterization tool 102 includes filter system 110. According to some embodiments, filter system 110 is configured to be positioned between sample 122 and X-ray detector 108 in characterization tool 102 such that a ratio of counts of X-ray photons of interest (also referred to herein as “information-carrying photons”) that reach detector 108 to total photon counts that reach detector 108 is increased. According to some embodiments, the ratio of counts of X-ray photons of interest can be increased by at least about 6-fold, at least about 7-fold, at least about 8-fold, at least about 9-fold, at least about 10-fold. Each possibility is a separate embodiment. Figure 1

[0060] In some embodiments, the ratio of counts of X-ray photons of interest can be increased by about 6 to about 10-fold, about 8 to about 10-fold, about 9 to about 10-fold. Each possibility is a separate embodiment.

[0061] Advantageously, in some embodiments, the increase in the ratio of counts of X-ray photons of interest can be achieved by filter system 110 without changing the X-ray detector hardware of characterization tool 102.

[0062] According to some embodiments, filter system 110 can be replaced in situ.

[0063] According to some embodiments, filter system 110 includes band-stop filter 112. According to some embodiments, filter system 110 is a notch filter. Each possibility is a separate embodiment.

[0064] According to some embodiments, band-stop filter 112 is configured to attenuate / filter out X-ray photons having a predetermined energy before the X-ray photons reach the X-ray photon energy dispersive detector. Thereby, in some embodiments, the output count rate of photons of interest reaching the X-ray photon energy dispersive detector is increased / maximized. In other words, in some embodiments, filter system 110 can be configured to (i) increase the relative proportion of photons of interest reaching the detector, and (ii) reduce the photon input count rate by filtering / removing irrelevant photons reaching the detector. In some embodiments, the irrelevant photons can include a majority of the photons reaching the detector. As a non-limiting example, in the case that sample 122 includes a Si wafer, the irrelevant photons reaching the EDX detector can include Si photons.

[0065] ​According to some embodiments, the band-stop filter 112 can optionally comprise an electron filter for attenuating backscattered electrons and / or secondary electrons, as set out in greater detail elsewhere herein. In some embodiments, the electron filter is configured to attenuate backscattered electrons and / or secondary electrons emitted from the sample 122. According to some embodiments, the electron filter is positioned such that the electrons are attenuated before reaching the band-stop filter 112, thereby preventing the electrons from causing excitation of photons due to entering the band-stop filter 112.

[0066] According to some embodiments, the band-stop filter 112 can optionally comprise one or more additional band-stop filters. In some embodiments, each of the one or more additional band-stop filters is configured to attenuate / filter out X-ray photons having a different respective predetermined energy.

[0067] According to some embodiments, the band-stop filter 112 can be made of or comprise a plurality of thin films, as set out in greater detail elsewhere herein.

[0068] According to some embodiments, and as depicted in Figure 1 , the characterization tool 102 comprises a controller 118. According to some embodiments, the controller 118 can be functionally associated with any one and more components of the characterization tool 102. According to some embodiments, the controller 118 can be functionally associated with the stage 120. According to some embodiments, the controller 118 is configured to control and / or synchronize the operation and functionality of any one and more components of the characterization tool 102, such as but not limited to the stage 122, the one and more vacuum pumps, the e-beam source 104, the electron detector 106, the X-ray detector 108, etc., or any combination thereof. Each possibility is a separate embodiment.

[0069] According to some embodiments, there is provided a filter system for filtering photons by energy. Figure 2A A cross-sectional side view schematically illustrating an example of a filter system 210, according to some embodiments. According to some embodiments, the filter system 210 can be the same, similar or different than the filter system 110 of Figure 1 .

[0070] According to some embodiments, the filter system 210 comprises a band-stop filter 212. In some embodiments, the band-stop filter 212 can be a notch filter.

[0071] According to some embodiments, at least a portion of the band-stop filter 212 is made of or comprises a plurality of thin films, as shown in Figure 2B . In some embodiments, the plurality of thin films can be stacked on one another.

[0072] In some embodiments, the thickness of each of the plurality of thin films can be substantially similar or the same. In some embodiments, the thickness of each of the plurality of thin films can be different. In some embodiments, a first portion of the plurality of thin films can have substantially the same thickness and a second portion of the plurality of thin films can have a different thickness. Each possibility represents a separate embodiment.

[0073] In some embodiments, the thickness of each of the plurality of thin films can be in a range from about 50 nm to about 5 pm, from about 50 nm to about 10 nm, from about 50 nm to about 20 nm, from about 40 nm to about 20 nm, from about 30 nm to about 5 nm, from about 10 nm to about 5 nm, etc. Each possibility represents a separate embodiment.

[0074] According to some embodiments, at least a portion of the plurality of thin films can be selected from: Hf, Al, BN, TiN, Si3N4, V, Ti, Teflon, Mn, Cr, Fe, or AI2O3, as set out in greater detail elsewhere herein.

[0075] In some embodiments, the band-stop filter 212 can optionally include an electron filter 216 Figure 2A and Figure 2B According to some embodiments, the electron filter 216 can include a backscattered electron filter configured to attenuate / filter out backscattered electrons emitted from the sample. According to some embodiments, the electron filter 216 can be configured to attenuate / filter out secondary electrons emitted from the sample. According to some embodiments, the electron filter 216 can be configured to attenuate / filter out backscattered electrons and secondary electrons emitted from the sample. Each possibility represents a separate embodiment.

[0076] In some embodiments, backscattered electrons and / or secondary electrons can be emitted from the tested sample as a result of the primary e-beam impinging the tested sample. In other words, in some embodiments, the emitted backscattered electrons and / or secondary electrons can be referred to as parasitic / irrelevant signals emitted from the tested sample. In some embodiments, the backscattered electrons and / or secondary electrons can cause photons to be emitted from the band-stop filter 212, thus causing transmission of parasitic photons.

[0077] According to some embodiments, the electron filter 216 can be made of or include a plurality of thin films. According to some embodiments, and as schematically depicted in Figure 2C each of the plurality of thin films can be in a range from about 50 nm to about 5 pm, from about 50 nm to about 10 nm, from about 50 nm to about 20 nm, from about 40 nm to about 20 nm, from about 30 nm to about 5 nm, from about 10 nm to about 5 nm, etc. Each possibility represents a separate embodiment.

[0078] According to some embodiments, the electronic filter 216 may be made of or contain the following: (a) Mylar and Hf, (b) Mylar and Fe, (c) Mylar and Al2O3, and (d) Al and Mg. Each possibility is a separate embodiment.

[0079] According to some embodiments, the band-stop filter 212 may include one or more band-stop filters 214 configured to attenuate X-ray photons having a predetermined energy. In other words, in some embodiments, each of the filters 214 is configured to attenuate / filter out X-ray photons with a corresponding predetermined energy while allowing the transmission of X-ray photons of interest (i.e., X-ray photons with the energy of interest).

[0080] In some embodiments, the predetermined energy of the attenuated X-ray photons may be in the range of about 50 eV to about 15 keV. In some embodiments, the predetermined energy of the attenuated X-ray photons may be in the range of about 50 eV to about 30 keV.

[0081] According to some embodiments, the composition of the band-stop filter 212, i.e., the material used to fabricate each filter layer 114, can be determined based on the properties of the photons of interest and / or irrelevant photons. According to some embodiments, a band-stop filter can be replaced with another band-stop filter in the characterization tool as needed.

[0082] As a non-restrictive example, and as Figure 2C As schematically depicted, filter 214 may include a first layer / film 214a, a second layer / film 214b', and a third layer / film 214c. According to some embodiments, filter 214 may be in the form of multiple stacked films / layers having predetermined and / or tunable transmission characteristics. Those skilled in the art will understand that the number of one or more additional band-stop filters may vary.

[0083] According to some embodiments, the thickness of each layer / film of one or more additional bandstop filters 214 may be in the range of about 50 nm to about 5 μm, about 50 nm to about 10 nm, about 50 nm to about 20 nm, about 40 nm to about 20 nm, about 30 nm to about 5 nm, about 10 nm to about 5 nm, etc. Each possibility is a separate embodiment.

[0084] As a non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through Hf and spectral lines truncate with Si, wherein multiple thin films include backscattered electron filters, and wherein at least a portion of the multiple thin films is made of or contains Mylar and Hf.

[0085] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through F and Fe and spectral lines cut off by Co, wherein multiple thin films include backscattered electron filters, and wherein at least a portion of the multiple thin films of the band-stop filter is made of or contains Mylar and Fe.

[0086] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through Al and spectral lines being truncated by Si, wherein multiple thin films include backscattered electron filters, and wherein at least a portion of the multiple thin films of the bandstop filter is made of or contains Mylar and Al2O3.

[0087] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through Ge and spectral lines being truncated by Si, wherein multiple thin films include backscattered electron filters, and wherein at least a portion of the multiple thin films of the bandstop filter is made of or contains Al and Mg.

[0088] According to some embodiments, the band-stop filter 212 may not have a backscattered electronic filter.

[0089] As a non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through Hf and spectral lines truncate with Si, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Hf.

[0090] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through Ge and spectral lines being truncated by Si, wherein the bandstop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the bandstop filter is made of or contains Al.

[0091] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through N and spectral lines truncate Ti, wherein the bandstop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the bandstop filter is made of or contains BN.

[0092] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through N and spectral lines truncate with Ti, wherein the bandstop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the bandstop filter is made of or contains TiN.

[0093] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through N and spectral lines truncate Ti, wherein the bandstop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the bandstop filter is made of or contains Si3N4.

[0094] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through N and Ti and spectral lines truncate O, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains V.

[0095] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through N and Ti and spectral lines truncate O, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Ti.

[0096] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through F and spectral lines being truncated for Fe, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Teflon.

[0097] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through O and spectral lines truncate Fe and F, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Mn.

[0098] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through O and spectral lines being truncated by F, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Cr.

[0099] As another non-limiting example, the band-stop filter 212 may include a window function having energy spectral lines passing through F and Fe and spectral lines truncate Co, wherein the band-stop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the band-stop filter is made of or contains Fe.

[0100] As another non-limiting example, the bandstop filter 212 may include a window function having energy spectral lines passing through Al and spectral lines being truncated by Si, wherein the bandstop filter does not have a backscattered electron filter, and wherein at least a portion of the plurality of thin films of the bandstop filter is made of or contains Al2O3.

[0101] According to one aspect of some embodiments, a method for filtering photons by energy is provided. According to some embodiments, the disclosed method can be used for metrology of samples, such as those obtained using an electron microscope. Figure 3A A flowchart of this method, namely method 300, is presented according to some embodiments. Method 300 can be implemented using system 100 and similar systems. See also... Figures 3B-3C This is an exemplary illustration of a filter system 410 in operation, according to some embodiments. It should be noted that the electron beam and the sample under test 422 do not form part of the filter system 410.

[0102] According to some embodiments, at step 302, the method may include placing a primary electron beam (in...) Figure 3B The primary electron beam (labeled "E-beam") is directed onto the sample under test, thereby initiating the emission of X-ray photons and electrons from the sample. As a non-limiting example, the primary electron beam can be generated by the electron gun of a SEM, TEM, etc. Each possibility is a separate embodiment.

[0103] According to some embodiments, and as Figure 3B The diagram schematically depicts the emission of X-ray photons, backscattered electrons, and secondary electrons (SE) from a test sample 422 as an E-beam strikes the sample. In some embodiments, a first portion of the X-ray photons may include photons of interest, and a second portion may include parasitic / irrelevant photons. Optionally, in some embodiments, the emitted backscattered electrons and / or secondary electrons may also be referred to as parasitic / irrelevant signals emitted from the test sample 422.

[0104] According to some embodiments, at step 304, which is an optional step, the method may include using an electronic filter (such as electronic filter 416) to attenuate backscattered and / or secondary electrons emitted from the sample under test. According to some embodiments, the electronic filter may also absorb / attenuate at least a portion of the photons. According to some embodiments, the electronic filter may be configured to attenuate photons of specific energies in order to minimize the attenuation / absorption of photons of interest. According to some embodiments, if no electronic filter is applied, electrons may be deflected from a band-stop filter.

[0105] According to some embodiments, at step 306, the method may include attenuating X-ray photons with a predetermined energy by using a band-stop filter (such as band-stop filter 414) positioned between the sample under test and the X-ray photon energy dispersion detector.

[0106] According to some embodiments, step 306 may optionally include passing through a band-stop filter and one or more additional band-stop filters (in... Figure 3B (Not shown in the image) Attenuation of multiple X-ray photons with predetermined energies.

[0107] It should be understood that if an electronic filter is included, the electronic filter is positioned such that electrons emitted from the sample reach the electronic filter before reaching the band-stop filter.

[0108] According to some embodiments, at step 308, the method may include receiving X-ray photons of interest via an X-ray photon energy dispersive detector such that the ratio of the count of X-ray photons of interest arriving at the detector to the total count of photons arriving at the detector is increased.

[0109] According to some embodiments, the counting ratio can be increased by approximately 5 times or more, approximately 6 times or more, approximately 7 times or more, approximately 8 times or more, approximately 9 times or more, approximately 10 times or more. Each possibility is a separate embodiment.

[0110] According to some embodiments, at step 310, the method may include outputting a signal indicating the X-ray photons of interest.

[0111] Now for reference Figure 3C The diagram illustrates the transmittance of photons emitted from the sample in response to an electron beam striking the sample. Dashed lines show the transmittance of photons obtained through the first filter layer (T1), dashed lines show the transmittance of photons obtained through the second filter layer (T2), and solid lines show the transmittance of photons obtained through both the first and second filter layers (T1*T2). Vertical line 514 represents the photon energy of the photon of interest, i.e., the photon that should reach the EDX detector. Vertical lines 518a and 518b represent the photon energy of parasitic photons (i.e., photons that do not carry information of interest). Vertical line 518a represents parasitic photons emitted by the sample due to an electron beam striking the sample. Vertical line 518b represents parasitic photons emitted due to backscattered electrons and / or secondary electrons striking the first filter.

[0112] As can be seen from the figure, applying either the first or second filter layer significantly attenuates the count of parasitic photons (without a filter, all photons are transmitted—i.e., a horizontal line with transmittance = 1 is obtained). Furthermore, while the combination of filter layer 1 and filter layer 2 results in an overall reduction in the count of photons of interest reaching the EDX, this reduction is significantly less than the reduction achieved for parasitic photons; only about 10% of silicon photons reach the EDX, and the count of photons generated by backscattered electrons reaching the EDX is also significantly reduced. Advantageously, this means that the ratio of the count of X-ray photons of interest reaching the detector to the total number of photons reaching the detector is further increased compared to using a single filter.

[0113] According to some embodiments, the term "sample" may refer to a semiconductor device and / or its components / elements. According to some embodiments, the term "sample" may refer to a wafer (e.g., a Si wafer, a GaAs wafer, etc.), such as a patterned wafer, an unpatterned wafer, etc. According to some embodiments, the term "sample" may refer to a diode, a transistor, an integrated circuit, a system-on-a-chip, etc., and / or any components / elements thereof. According to some embodiments, the term "sample" may refer to an electronic device and / or its components / elements. According to some embodiments, the term "sample" may refer to an energy storage device or its components / elements. According to some embodiments, the term "sample" may refer to an optoelectronic device or any components / elements thereof. According to some embodiments, the term "sample" may refer to photoresist. Each possibility is a separate embodiment.

[0114] In the specification and claims of this application, the words “comprising” and “having” and their various forms are not limited to members of the list to which the words may be associated.

[0115] As used herein, the term "about" can be used to specify the value of a quantity or parameter (e.g., the length of an element) as being within a continuous range of values ​​that are close to (and include) a given (statement) value. According to some embodiments, "about" can specify the value of a parameter as being between 80% and 120% of a given value. For example, the statement "the length of the element is about 1 m" is equivalent to the statement "the length of the element is between 0.8 m and 1.2 m". According to some embodiments, "about" can specify the value of a parameter as being between 90% and 110% of a given value. According to some embodiments, "about" can specify the value of a parameter as being between 95% and 105% of a given value.

[0116] As used herein, the terms “substantially” and “about” may be interchangeable according to some embodiments.

[0117] As used herein, the terms “sample” and “sample” may be used interchangeably according to some embodiments.

[0118] According to some embodiments, the term "sample" may refer to any type of sample suitable for characterization under electron beam irradiation. As a non-limiting example, the term "sample" may refer to any type of sample suitable for characterization using scanning electron microscopy.

[0119] Those skilled in the art will readily understand that the order in which the above operations are listed is not unique.

[0120] It will be understood that certain features of this disclosure described in the context of a single embodiment for clarity may also be provided in combination in a single embodiment. Conversely, various features of this disclosure described in the context of a single embodiment for brevity may also be provided individually or in any suitable sub-combination or as appropriate in any other described embodiment of this disclosure. Unless explicitly stated otherwise, features described in the context of an embodiment shall not be considered essential features of that embodiment.

[0121] While the stages of a method according to some embodiments may be described in a specific sequence, the methods of this disclosure may include some or all of the described stages performed in a different order. The methods of this disclosure may include several or all of the described stages. Unless explicitly stated otherwise, a particular stage in the disclosed methods should not be considered a fundamental stage of the method.

[0122] Although this disclosure has been described in conjunction with specific embodiments thereof, it should be understood that numerous alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, this disclosure covers all such alternatives, modifications, and variations falling within the scope of the appended claims. It will be understood that this disclosure is not necessarily limited in its application to the details of the construction and arrangement of the components and / or methods set forth herein. Other embodiments may be practiced, and embodiments may be carried out in various ways.

[0123] The wording and terminology used herein are for descriptive purposes only and should not be construed as restrictive. Any citation or attribution of references in this application should not be construed as an admission that such references are prior art to this disclosure.

[0124] Section headings are used in this document to facilitate understanding of the instructions and should not be construed as necessarily restrictive.

Claims

1. A sample characterization system, the sample characterization system comprising: A characterization tool configured to generate an electron beam directed toward the sample under test; An energy-dispersive X-ray photon detector (EDX) is configured to collect X-ray photons emitted from the sample under test. as well as A filter assembly, positioned within the characterization tool between the sample under test and the EDX, includes a band-stop filter configured to allow information-carrying X-ray photons with a predetermined energy range to pass through and to attenuate irrelevant photons with an energy range different from the predetermined energy range from reaching the EDX. This increases the ratio between the count of information-carrying X-ray photons reaching the EDX and the total number of photons reaching the EDX, compared to a sample characterization system without the filter assembly.

2. The system of claim 1, wherein the filter assembly further comprises an electronic filter configured to attenuate backscattered electrons emitted from the test sample; and / or wherein the filter assembly further comprises a deflector configured to deflect electrons away from the filter assembly.

3. The system of claim 1, wherein the filter assembly further comprises one or more additional band-stop filters, each of the one or more additional band-stop filters being configured to filter out X-ray photons having a corresponding predetermined energy.

4. The system of claim 1, wherein at least a portion of the band-stop filter is made of or comprises a plurality of thin films.

5. The system of claim 4, wherein the thickness of each of the plurality of films is in the range of 50 nm to 5 μm.

6. The system of claim 4, wherein at least a portion of the plurality of thin films comprises: Hf, Al, BN, TiN, Si3N4, V, Ti, Teflon, Mn, Cr, Fe, Al2O3, or any combination thereof.

7. The system of claim 4, wherein at least a portion of the plurality of thin films comprises: a. Mylar and Hf, b. Mylar and Fe, c. Mylar and Al2O3, or d.Al and Mg.

8. The system of claim 1, wherein the band-stop filter is a notch filter.

9. The system of claim 1, wherein the filter component or a portion thereof is replaceable in situ.

10. The system of claim 1, wherein the ratio is increased by 8 times or more.

11. The system of claim 1, wherein the predetermined energy range is about 50 eV to 15 keV.

12. The system of claim 1, wherein the predetermined energy range is adjustable, thereby allowing its value to be adjusted.

13. The system of claim 1, wherein the characterization tool comprises an electron microprobe, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a scanning TEM (STEM).

14. A method for filtering photons by energy, the method comprising: A primary electron beam is directed onto the sample under test, thereby initiating the emission of X-ray photons and electrons from the sample under test. X-ray photons with energies different from a predetermined energy range of information-carrying X-ray photons are attenuated by using a band-stop filter positioned between the test sample and the EDX. By detecting the information-carrying X-ray photons using the EDX, the ratio between the count of information-carrying X-ray photons arriving at the EDX and the total number of photons arriving at the EDX is increased compared to a sample characterization system without the filter assembly; and The output signal indicates the information-carrying X-ray photons detected by the EDX.

15. The method of claim 14, the method further comprising attenuating backscattered and / or secondary electrons emitted from the sample under test; and / or the method further comprising deflecting the backscattered and / or secondary electrons away from the filter assembly.

16. A filter assembly for filtering photons by energy, the filter assembly including a band-stop filter configured to allow information-carrying X-ray photons with a predetermined energy range to pass through it and to block irrelevant photons from reaching an energy dispersive X-ray detector (EDX), thereby increasing the ratio between the count of information-carrying X-ray photons reaching the EDX and the total count of photons reaching the EDX compared to a sample characterization system without the filter assembly; The band-stop filter is at least partially made of or comprises multiple thin films having a thickness of approximately 50 nm to 5 μm; and At least a portion of the plurality of films comprises materials selected from the following: Hf, Al, BN, TiN, Si3N4, V, Ti, Teflon, Mn, Cr, Fe, or Al2O3.

17. The filter assembly of claim 16, wherein the counting ratio is increased by 8 times or more.

18. The filter assembly of claim 16, further comprising an electronic filter configured to attenuate backscattered electrons and / or secondary electrons emitted from the sample under test; and / or the filter assembly further comprising a deflector configured to deflect electrons away from the filter assembly.

19. The filter assembly of claim 16, wherein at least a portion of the plurality of thin films comprises: a. Mylar and Hf, b. Mylar and Fe, c. Mylar and Al2O3, or d.Al and Mg.

20. The filter assembly of claim 16, wherein the predetermined energy is in the range of 50 eV to 15 keV.

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