Analysis system, analysis method, analysis program

Abstract

The purpose of the present disclosure is to obtain sufficient analysis accuracy and throughput when a sample is analyzed by using two or more types of elemental analysis devices having different energy resolutions. An analysis system according to the present disclosure performs elemental analysis using a second element analysis device having a higher energy resolution than a first element analysis device, on the basis of the results obtained by comparing a first energy spectrum of a sample to be analyzed, which is acquired using the first element analysis device, and a second energy spectrum of a reference sample, which is acquired using the first element analysis device (see Fig. 2).

Description

Technical Field

[0001] The present disclosure relates to an analysis system for analyzing elements contained in a sample.

Background Art

[0002] By combining an electron microscope and an elemental analyzer, information such as the elemental species and elemental distribution of the site observed using the electron microscope can be obtained. As the elemental analyzer, for example, an energy dispersive X-ray spectroscopy (EDS) device or the like is used. As the electron microscope, for example, a scanning electron microscope (SEM) or the like is used.

[0003] The following Patent Document 1 describes a technique for analyzing elemental distribution using EDS and performing further elemental analysis on each distribution region obtained as a result using a wavelength dispersive X-ray spectrometer (WDS).

[0004] The following Non-Patent Document 1 describes an X-ray analyzer using a transition edge sensor (TES) having higher energy resolution than EDS.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Compared with the TES, the EDS has a high measurement throughput but a low energy resolution, so there is a possibility that elements cannot be sufficiently identified. Therefore, when elements cannot be sufficiently identified using the EDS, it is conceivable to switch the measuring device to the TES for further analysis. However, although the TES has a high energy resolution, its throughput is low. Therefore, if the TES is used too much, there is a concern that the measurement throughput will drop too much.

[0008] Non-Patent Document 1 compares the characteristics of the EDS and the TES, but does not describe on what criteria to switch between the two devices. Patent Document 1 creates an element distribution map using the EDS and then uses the WDS for each element phase, and does not sufficiently consider achieving both energy resolution and throughput between the EDS and the WDS.

[0009] The present disclosure has been made in view of the above problems, and aims to obtain sufficient analysis accuracy and throughput when analyzing a sample using two or more types of elemental analyzers having different energy resolutions.

Means for Solving the Problems

[0010] The analysis system according to the present disclosure performs elemental analysis using a second elemental analyzer having a higher energy resolution than the first elemental analyzer, based on the result of comparing the first energy spectrum of a target sample acquired using the first elemental analyzer with the second energy spectrum of a reference sample acquired using the first elemental analyzer.

Advantages of the Invention

[0011] According to the analysis system of the present disclosure, when analyzing a sample using two or more types of elemental analyzers having different energy resolutions, sufficient analysis accuracy and throughput can be obtained. Other problems, configurations, advantages, etc. of the present disclosure will become apparent from the description of the following embodiments.

Brief Description of the Drawings

[0012] [Figure 1] It is a configuration diagram of an analysis system 1 according to Embodiment 1. [Figure 2] It is a flowchart for explaining the operation of the analysis system 1. [Figure 3] An example of the first energy spectrum 31 and the second energy spectrum 32 in S203 is shown. [Figure 4] It is a diagram showing another example of the matching process between energy spectra. [Figure 5] It is a flowchart for explaining the operation of the analysis system 1 when matching energy spectra between the target part 141 and the reference part 142. [Figure 6] It is an example showing together the energy spectrum acquired using EDS and the energy spectrum acquired using TES. [Figure 7] It is a flowchart for explaining the operation of the analysis system 1 in Embodiment 2. [Figure 8] It is a cross-sectional view schematically showing the acceleration voltage of the electron beam 151 and the spread of the electron beam 151 in the sample 16. [Figure 9] 10 is a diagram illustrating energy spectra when the target portion 141 is an organic material and when it is an inorganic material. [Figure 10] 10 is a flowchart illustrating the operation of the analysis system 1 in the third embodiment. [Figure 11] 10 is a flowchart illustrating the operation of the analysis system 1 according to the fourth embodiment. [Figure 12] An example of a user interface provided by the computer system 13 is shown. [Figure 13] 10 shows another example of a user interface provided by the computer system 13. DETAILED DESCRIPTION OF THE INVENTION

[0013] <First Embodiment> 1 is a configuration diagram of an analysis system 1 according to a first embodiment of the present disclosure. The analysis system 1 is an apparatus for analyzing elements contained in a sample 16. The analysis system 1 generally includes a first elemental analysis apparatus 11, a second elemental analysis apparatus 12, a computer system 13, an electron beam control apparatus 14, and an electron beam generation apparatus 15.

[0014] The first elemental analysis device 11 is a device that analyzes elements contained in a sample 16, and can be configured, for example, by an EDS device. The second elemental analysis device 12 is a device that analyzes elements contained in a sample 16, and has higher energy resolution than the first elemental analysis device 11. The second elemental analysis device 12 can be configured, for example, by a TES device. The electron beam generator 15 irradiates the sample 16 with an electron beam 151. The electron beam controller 14 controls the electron beam generator 15. The sample 16 is, for example, a semiconductor substrate.

[0015] First Embodiment: Outline of Operation of Analysis System 1 The electron beam generator 15 focuses the electron beam 151 on a specific location of the sample 16. As a result, secondary particles 152 are generated from the sample 16. The detector 153 detects the secondary particles 152 and outputs a detection signal representing its intensity to the electron beam control device 14. The computer system 13 generates an observation image (SEM image) of the sample 16 using the detection signal. The computer system 13 identifies, on the observation image, (a) a target part 141 (target sample) to be analyzed for elements, and (b) a reference part 142 (reference sample) for comparing the composition with the target part 141.

[0016] The positions of the target part 141 and the reference part 142 may be specified by the user while viewing the observation image, or may be specified by the computer system 13 itself by searching for a specific shape pattern by an appropriate method such as template matching. For example, the positions of fine particles on the sample (e.g., foreign matter if the sample 16 is a semiconductor substrate), defects in the shape pattern, etc. can be specified as the target part 141, and the positions where these do not exist can be specified as the reference part 142.

[0017] The target part 141 and the reference part 142 may be at different positions on the same sample, or the reference part 142 may be specified on a reference sample different from the sample having the target part 141. In any case, the target part 141 is the target sample for which elemental analysis is to be performed, and the reference part 142 is the reference sample serving as the comparison reference.

[0018] The electron beam generator 15 irradiates the electron beam 151 on the target part 141 and the reference part 142 respectively for a certain period of time. The first elemental analyzer 11 acquires the X-rays 161 (first X-rays) emitted from the target part 141 and the X-rays 161 (second X-rays) emitted from the reference part 142 respectively.

[0019] The computer system 13 acquires data describing the results of the first elemental analyzer 11 detecting the X-rays 161, and uses this to acquire the energy spectrum of the target part 141 (the first energy spectrum) and the energy spectrum of the reference part 142 (the second energy spectrum), respectively. The energy spectrum represents the wavelength on the horizontal axis in terms of energy (eV), and the number of detected photons (count number) on the vertical axis.

[0020] The computer system 13 determines whether to further perform elemental analysis using the second elemental analyzer 12 by comparing the first energy spectrum and the second energy spectrum. The details of this determination procedure will be described later.

[0021] Figure 2 is a flowchart for explaining the operation of the analysis system 1. Hereinafter, the procedure for the analysis system 1 to analyze the elements contained in the sample 16 will be described with reference to Figure 2. Each step can be implemented by the computer system 13 controlling each part of the analysis system 1.

[0022] (Figure 2: Steps S201 - S202) The first elemental analyzer 11 detects the X-rays 161 from each of the target part 141 and the reference part 142. The computer system 13 acquires the energy spectrum of the target part 141 (S201: the first energy spectrum) and the energy spectrum of the reference part 142 (S202: the second energy spectrum), respectively.

[0023] (Figure 2: Steps S203 - S204) The computer system 13 extracts a feature amount from the region B on the energy spectrum (S204) by comparing the first energy spectrum and the second energy spectrum (S203). An example of the region B will be described later.

[0024] (Figure 2: Steps S205 - S206) When one or more feature quantities are extracted in region B (S205: Yes), the computer system 13 further analyzes the elements in the target part 141 using the second element analyzer 12 (S206). When no feature quantity is extracted (S205: No), this flowchart ends without using the second element analyzer 12.

[0025] FIG. 3 shows an example of the first energy spectrum 31 and the second energy spectrum 32 in S203. In FIG. 3, an example of the energy spectrum in which feature quantities corresponding to carbon (C) and oxygen (O) are extracted is shown on the energy spectrum acquired by the first element analyzer 11.

[0026] The computer system 13 can set, for example, the peripheral region of the characteristic X-ray of the assumed element species as region B. In this example, an energy range of ±40 eV before and after each of the characteristic X-rays of carbon and oxygen (C-Kα ray: 273 eV, O-Kα ray: 525 eV) is set as region B.

[0027] Alternatively, the computer system 13 may set, as region B, the energy range in which a significant difference occurs between the first energy spectrum 31 and the second energy spectrum 32. In the example shown in FIG. 3, a significant difference occurs between the two in the energy range before and after the characteristic X-rays of carbon and oxygen respectively. Therefore, the computer system sets the same energy range as described above as region B. The difference between the energy spectra can be calculated, for example, by summing the squares of the differences in the count values between the spectra for each energy value.

[0028] <Embodiment 1: Matching Processing between Spectra> As an example of the feature amount in S204 to S205, assume a case where the difference between spectra is used. If the difference is equal to or greater than the threshold value, the difference can be used as the feature amount of the energy spectrum of the target part 141. However, in order to appropriately extract the difference, for the energy region where there is no difference in the elemental composition between the target part 141 and the reference part 142, the spectral values (count values on the vertical axis) need to match (not necessarily exactly match, but at least match to the extent that the difference between spectra is less than the reference value). Therefore, the computer system 13 adjusts any energy spectrum so that the difference between spectra in the region other than region B (region A in FIG. 3) is less than the reference value according to the following procedure.

[0029] The computer system 13 preferably sets an energy region where the feature amount is not extracted (that is, an energy region other than region B) as region A, and adjusts any energy spectrum so that the difference between each energy spectrum in region A is less than the reference value. Specifically, by multiplying the count value (spectral value) at each energy by an appropriate coefficient, the scale of the count value is adjusted so that the difference in region A is less than the reference value. As a result, for the energy region (region A) where there is no difference in the elemental composition between the target part 141 and the reference part 142, each energy spectrum will match. That is, the difference in the elemental composition clearly appears as a feature amount in region B. The process of adjusting the difference between the energy spectra in such region A to less than the reference value will be referred to as the inter-spectral matching process.

[0030] If the target portion 141 is small, it is desirable to lower the acceleration voltage of the electron beam 151. On the other hand, in order to generate the desired characteristic X-rays, the energy of the electron beam 151 must be higher than the energy of the characteristic X-rays. For example, if the target portion 141 is assumed to be a transition metal, the energy of the characteristic X-rays of transition metals is 1.5 keV or less, and considering the efficiency of X-ray generation, the acceleration voltage of the electron beam 151 should be 2.5 kV to 3 kV. In this case, the efficiency of generating characteristic X-rays above 2 keV is low, and the intensity of the continuous X-rays dominates the intensity of the characteristic X-rays. In other words, it is unlikely that the energy region above 2 keV will be set as region B. Therefore, if the target portion 141 is assumed to be a transition metal, the energy region above 2 keV is suitable for region A.

[0031] Figure 4 shows another example of matching processing between energy spectra. Here, we assume that the sample 16 is a silicon substrate. In this case, Si-Kα radiation is always obtained as X-rays from the silicon substrate. Furthermore, O-Kα radiation is always obtained as X-rays from oxygen attached to the substrate surface. Therefore, in this example, the energy region corresponding to Si-Kα and O-Kα in the energy spectrum is always set as region B.

[0032] If the O-Kα spectral peak is misaligned between the target portion 141 and the reference portion 142, the difference between the target portion 141 and the reference portion 142 in the spectral tail region of the O-Kα ray will be small, and there is a possibility that weak characteristic X-rays buried in the tail region will not be detected. A similar situation occurs with Si-Kα. Such a misalignment of the spectral peak occurs due to the absorption of Si-Kα ray and O-Kα ray of the substrate by the target portion 141.

[0033] Therefore, computer system 13 matches the spectral peaks of O-Kα and Si-Kα, and then obtains the difference between the energy spectrum of target portion 141 and the energy spectrum of reference portion 142. This makes it possible to more reliably extract the difference between the two in the tail region. Specifically, computer system 13 adjusts one of the energy spectra so that the difference between the spectral peaks of O-Kα and Si-Kα is less than a reference value. That is, by multiplying the count value at each energy by an appropriate coefficient, the scale of the count value is adjusted so that the difference between the spectral peaks in region B is less than the reference value. Figure 4 shows the result. This process of matching spectral peaks is also an example of a spectral matching process.

[0034] After performing matching on the spectral peaks, the computer system 13 compares spectra 31 and 32 in the energy range outside of the peaks. In Fig. 4, the difference between the spectra is evident in the base of region B. Based on the comparison results, the computer system 13 can extract a feature (in this example, the difference between the spectra).

[0035] 5 is a flowchart illustrating the operation of the analysis system 1 when matching energy spectra between the target portion 141 and the reference portion 142. In this flowchart, in addition to the flowchart described in FIG. 2, S501 is added between S202 and S203. In S501, the computer system performs matching between energy spectra as described in FIGS. 3 and 4. These matching processes can also be used in combination.

[0036] <Embodiment 2> Figure 6 shows an example of an energy spectrum obtained using EDS and a TES. In this example, a weak Cu-Lα line (930 eV) is present near the transition metal Ni-Lα line (853 eV) and Ni-Lβ line (868 eV).

[0037] Transition metal information can be important information for the user, and as a user, the user does not want to miss even the small X-ray peak information of the transition metal. However, when there are minute sub-peaks near the main peak as shown in FIG. 6, there is a high possibility of missing such weak sub-peaks if only the first elemental analyzer 11 (EDS) is used. In Embodiment 2 of the present disclosure, a procedure for detecting such sub-peaks will be described. The configuration of the analysis system 1 is the same as that in Embodiment 1.

[0038] As illustrated in FIG. 6, an example in which a minute sub-peak is buried is a case where the peak of the energy spectrum of the transition metal is large. In FIG. 6, the Ni spectrum of 853 eV corresponds to this. Therefore, in the present embodiment, when there is a characteristic amount of the transition metal (for example, a peak corresponding to Ni) in the energy spectrum of the target portion 141 (or the reference portion 142), in order to detect a sub-peak that may be buried, the second elemental analyzer 12 is used. The buried sub-peak can be either a transition metal or an element other than the transition metal. FIG. 6 shows an example in which both the large peak and the sub-peak are transition metals.

[0039] FIG. 7 is a flowchart for explaining the operation of the analysis system 1 in the present Embodiment 2. In this flowchart, in addition to the flowchart described in FIG. 2, S701 to S702 are added after S205: none. For convenience of description, the part before S204 is omitted.

[0040] (FIG. 7: Step S701) If one or more characteristic quantities are not extracted in S205, the computer system 13 further determines whether the characteristic quantity of the transition metal is included in the first energy spectrum. The energy range for determining the presence or absence of the transition metal may be region B or other than that. If a transition metal is included, the process proceeds to S206, and the second elemental analyzer 12 is used to analyze the transition metal in detail. If no transition metal is included, the process proceeds to S701. Whether a transition metal is included or not can be determined by whether a spectral peak corresponding to the transition metal (the peak of Ni at 853 eV in FIG. 6) exists or not.

[0041] (FIG. 7: Step S702) The computer system 13 determines whether the target part 141 is either an inorganic substance or an organic substance. In the present embodiment, since a scenario where the user is interested in inorganic substances is assumed, if it is an organic substance, this flowchart is terminated. If it is an inorganic substance, the process proceeds to S206, and the second elemental analyzer 12 is used to analyze the inorganic substance in detail. The procedure for determining whether it is an inorganic substance or an organic substance will be described below.

[0042] FIG. 8 is a cross-sectional side view schematically showing the acceleration voltage of the electron beam 151 and the spread of the electron beam 151 in the sample 16. The higher the acceleration voltage of the electron beam 151 and the smaller the size of the target part 141, the higher the probability that the electron beam 151 penetrates the target part 141, and the smaller the amount of X-rays 161 from the target part 141. On the other hand, there is a correlation between the ionization cross-section, which is an index of X-ray generation efficiency, and the overvoltage ratio. When the overvoltage ratio is approximately 3, the ionization cross-section is maximized. Since the characteristic X-ray energy of carbon, which is the main component of the organic substance, is 273 eV, the acceleration voltage of the electron beam 151 is preferably about 1 kV in order to maximize the ionization cross-section.

[0043] FIG. 9 is a diagram illustrating the energy spectra when the target portion 141 is an organic substance and when it is an inorganic substance, respectively. The upper part of FIG. 9 shows a spectral image in the vicinity of the C-Kα line when the target portion 141 is an organic substance and the reference portion 142 is silicon. When the target portion 141 is carbon, the peak intensity of C-Kα becomes higher than that of the reference portion 142. The lower part of FIG. 9 shows a spectral image in the vicinity of the C-Kα line when the target portion 141 is an inorganic substance and the reference portion 142 is silicon. When the electron beam 151 irradiates the target portion 141 and the sample 16 (silicon), a carbon film is always formed on the surface depending on the degree of vacuum in the vacuum chamber housing the optical system unit 154 (carbon contamination). As a result, even when the target portion 141 is an inorganic substance, a carbon spectrum similar to that of the silicon substrate can be obtained from the target portion 141. Therefore, in this case, the difference in the C-Kα line peak between the target portion 141 and the reference portion 142 is small.

[0044] As described above, when the target portion 141 is an organic substance, the difference in the spectral peak of the C-Kα line is large between the target portion 141 and the reference portion 142, and when it is an inorganic substance, the difference is small. Based on this difference in S702, the computer system 13 can determine whether the target portion 141 is an organic substance or an inorganic substance. Specifically, if the difference in the spectral peak in the vicinity of the C-Kα line between the target portion 141 and the reference portion 142 is equal to or greater than the threshold value, it can be determined that the target portion 141 is an organic substance, and if it is less than the threshold value, it is an inorganic substance.

[0045] As described with reference to FIG. 8, the difference between such spectral peaks appears most prominently when the acceleration voltage of the electron beam 151 is about 1 kV (or less). Therefore, the computer system 13 changes the acceleration voltage of the electron beam 151 to 1 kV or less after S205 and before starting S702. Thereby, even when no feature amount is detected in S205, the difference between the spectral peaks described with reference to FIG. 9 can be prominently identified.

[0046] The determination of organic and inorganic substances does not necessarily have to be carried out using the difference between spectral peaks, and feature quantities equivalent to the difference may also be used. For example, it is conceivable to compare the spectral areas near the peaks between Spectra 31 and 32. Other similar feature quantities can also be used.

[0047] <Embodiment 3> In Embodiment 2, when there is no difference between the target part 141 and the reference part 142 (that is, when there is no feature quantity of the energy spectrum, S205: none), it was explained that the process proceeds to S701 to analyze the transition metal. Instead of this, when a transition metal is obtained during the acquisition of the X-ray spectrum of the target part 141, the analysis using the second element analyzer 12 may be started. A specific example thereof will be described in Embodiment 3 of the present disclosure. The configuration of the analysis system 1 is the same as that in Embodiment 1.

[0048] FIG. 10 is a flowchart for explaining the operation of the analysis system 1 in the present Embodiment 3. In S1001, the computer system 13 acquires the energy spectrum of the target part 141 using the first element analyzer 11. The subsequent operations are the same as those after S701 in FIG. 7. That is, when a transition metal is detected when the energy spectrum is acquired by the first element analyzer 11, the spectrum of the reference part 142 is not acquired, and the analysis using the second element analyzer is started (S206). This is effective when shifting from the analysis using the first element analyzer 11 to the analysis using the second element analyzer 12 in a short time.

[0049] However, as described with reference to FIG. 9, when determining inorganic / organic substances, the acceleration voltage of the electron beam 151 may be switched. When switching the acceleration voltage again when proceeding from S702 to S206, a certain amount of time is required for the switching. Therefore, when the feature quantity of the transition metal is not included in the energy spectrum in S701, both S702 and S206 may not be performed and the flowchart may be terminated. Thereby, the analysis of the transition metal is prioritized and the shortening of the measurement time is prioritized.

[0050] The computer system 13 may switch whether to execute the flowchart of FIG. 10, for example, according to a user's designation. That is, if the user desires to shift from the analysis using the first elemental analyzer 11 to the analysis using the second elemental analyzer 12 in a short time, FIG. 10 may be executed; otherwise, the flowchart described in Embodiments 1 to 2 may be executed.

[0051] <Embodiment 4> FIG. 11 is a flowchart for explaining the operation of the analysis system 1 according to Embodiment 4 of the present disclosure. The inorganic / organic determination described with reference to FIG. 9 may be performed alone. In this case, the computer system 13 sets the acceleration voltage to 1 kV or less and then executes the procedure described with reference to FIG. 9. If the target portion 141 is an inorganic substance, further analysis is performed using the second elemental analyzer 12. This flowchart shows the above procedure.

[0052] The computer system 13 may switch whether to execute the flowchart of FIG. 11, for example, according to a user's designation. For example, if the position of the target portion 141 has been specified in advance and it is desired to know whether an inorganic substance exists at that position, FIG. 11 may be executed. Otherwise, the flowchart described in Embodiments 1 to 3 may be executed.

[0053] <Embodiment 5> FIG. 12 shows an example of a user interface provided by the computer system 13. In the above embodiments, the computer system 13 may receive an operation instruction from the user by displaying a user interface (GUI) as shown in FIG. 12 on the screen.

[0054] On the GUI, a first element analysis setting button and a second element analysis setting button are arranged. When each button is pressed, a pop-up screen (lower part of FIG. 12) for inputting respective times is displayed, and the user inputs the measurement time using the first element analyzer 11 and the measurement time using the second element analyzer 12 on that screen. If there are other necessary setting items besides time setting, they can be added arbitrarily.

[0055] The GUI further has a column in which position information output from an inspection device for identifying a particle position different from the analysis system 1 and particle (defect) number information are described. In this column, for example, the file name describing the first element analysis result and the file name describing the second element analysis result (spectrum, element information, etc.) are described. Further, a "Second Element Analysis Execution" column is provided so that it is possible to identify the samples 16 among the samples 16 analyzed using the first element analyzer 11 that have shifted to the analysis using the second element analyzer 12, and "〇" is described for the shifted samples 16.

[0056] When the first and second energy spectrum acquisition setting buttons are pressed, the computer system 13 displays on the screen the user interface described in FIG. 13 below.

[0057] FIG. 13 shows another example of the user interface provided by the computer system 13. The GUI displays an observation image (SEM image) of the sample 16. The SEM image includes a target part 141 and a reference part 142 respectively.

[0058] The GUI further has columns for setting the conditions for the first energy spectrum acquisition and the second energy spectrum acquisition. The user selects spot analysis or area analysis in the first energy spectrum acquisition and the second energy spectrum acquisition.

[0059] The GUI further has a field for selecting a method of matching between energy spectra. As the matching method, for example, (a) a manual method in which the user selects a range himself / herself, (b) 2 keV or higher (the procedure described in FIG. 3), (c) a method using the peak of the S-Kα line or the O-Kα line (the procedure described in FIG. 4) can be selected. When using the Si-Kα line and the O-Kα line, an energy range (ROI: Region of Interest) for comparing the first energy spectrum and the second energy spectrum is set. When the setting end button is pressed, the screen returns to the screen of FIG. 12.

[0060] When the user presses the first element analysis execution button on the screen of FIG. 12, the operations of each flowchart are performed. For a sample marked with "〇" in the second element analysis column, the analysis using the second element analyzer 12 may be automatically started, or this may be started when the second element analysis execution button is pressed.

[0061] The GUI may display each energy spectrum. For example, the energy spectrum of the target part 141, the energy spectrum of the reference part 142, etc. can be displayed. The result of the matching process and the process thereof may be displayed.

[0062] <Regarding the modification example of the present disclosure> The present disclosure is not limited to the above-described embodiments and includes various modification examples. For example, the above-described embodiments have been described in detail for easy understanding of the present disclosure, and it is not necessary to necessarily include all the configurations described. Also, a part of one embodiment can be replaced with the configuration of another embodiment. Also, the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, a part of the configuration of another embodiment can be added, deleted, or replaced.

[0063] In Embodiment 2, it was described that the acceleration voltage of the electron beam 151 is preferably about 1 kV, but this is just an example, and other acceleration voltages may be used. Also, the sub-peak of the transition metal shown in FIG. 6 is just an example, and there may be cases where the L line of the transition metal is buried in the trailing region of the K line of other light elements. Even in such cases, the buried transition metal can be detected by the procedure of Embodiment 2.

[0064] In the above embodiments, it was explained that the position for obtaining the X-ray energy spectrum is specified using the observation image of the sample 16 formed using the electron beam 151. As an example, when the sample 16 is a semiconductor wafer, the position of the fine particles (or defects in the shape pattern) attached to the sample surface is specified by the observation image, and the elements of the fine particles are specified by each elemental analyzer, whereby the cause of the defect or the like can be analyzed.

[0065] In the above embodiments, the computer system 13 can be configured by an arithmetic device such as a processor that executes a program implementing the procedures of each flowchart, and a storage device that stores the program. Alternatively, instead of this program, the computer system 13 can also be configured by hardware such as a circuit device implementing the same procedure.

Explanation of Reference Numerals

[0066] 1: Analysis system 11: First elemental analyzer 12: Second elemental analyzer 13: Computer system 141: Target part 142: Reference part 16: Sample

Claims

1. An analysis system for analyzing elements contained in a sample, comprising a computer system that analyzes elements contained in the sample using the result of detection of X-rays generated from the sample. The computer system acquires a first energy spectrum of first X-rays generated from a target sample using a first element analyzer. The computer system acquires a second energy spectrum of second X-rays generated from a reference sample using the first element analyzer. Based on the result of comparison between the first energy spectrum and the second energy spectrum, the computer system determines whether or not one or more characteristic amounts are present on the first energy spectrum or the second energy spectrum. When the characteristic amount is present, the computer system analyzes elements contained in the target sample using a second element analyzer having higher energy resolution than the first element analyzer. The analysis system according to claim 1, wherein the computer system determines whether or not one or more characteristic amounts are present by comparing the first energy spectrum and the second energy spectrum in a first energy range on the first energy spectrum or the second energy spectrum. When the characteristic amount is present, the computer system analyzes elements contained in the target sample using the second element analyzer. When the characteristic amount is not present, the computer system does not perform analysis using the second element analyzer. The analysis system according to claim 1, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range.

2. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range.

3. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range. The analysis system according to claim 2, wherein the computer system multiplies at least one of the spectrum values of the first energy spectrum or the second energy spectrum by a coefficient so that the difference between the first energy spectrum and the second energy spectrum becomes less than a threshold value in a second energy range different from the first energy range, and performs a first matching process. The computer system determines whether or not the characteristic amount is present by comparing the first energy spectrum and the second energy spectrum on which the first matching process has been performed in the first energy range.

4. The first elemental analyzer is a device that generates X-rays from the target sample and the reference sample by irradiating the target sample and the reference sample with electron beams, respectively. The second energy range is a range where the energy of the electron beam is 2 keV or more. The analysis system according to claim 3, characterized in that.

5. In the first energy range, the computer system performs a second matching process of multiplying a coefficient to at least one of the spectral values of the first energy spectrum or the second energy spectrum so that the difference between the first peak of the first energy spectrum and the second peak of the second energy spectrum is less than a threshold value. The computer system determines whether the characteristic quantity exists by comparing the first energy spectrum and the second energy spectrum that have undergone the second matching process in an energy range that does not match either the first peak or the second peak. The analysis system according to claim 2, characterized in that.

6. The target sample and the reference sample are silicon substrates. The first peak and the second peak are at least one of the spectral peaks of the Kα line of oxygen or the Kα line of silicon. The analysis system according to claim 5, characterized in that.

7. The computer system determines whether one or more characteristic quantities exist by comparing the first energy spectrum and the second energy spectrum in the first energy range on the first energy spectrum or the second energy spectrum. When the characteristic quantity exists, the computer system analyzes the elements contained in the target sample using the second elemental analyzer. When the characteristic quantity does not exist, the computer system determines whether a characteristic quantity of a transition metal is included in the first energy spectrum or the second energy spectrum. When the characteristic quantity of the transition metal is detected, the computer system analyzes the elements of the transition metal using the second elemental analyzer. The analysis system according to claim 1, characterized in that.

8. When it is determined that the characteristic quantity of the transition metal is not included, the computer system determines whether the target sample is either an inorganic substance or an organic substance. The analysis system according to claim 7, characterized in that.

9. The computer system detects a difference between the first energy spectrum and the second energy spectrum in the third energy range as the feature amount in the third energy range, and if the difference is equal to or greater than a threshold value, the computer system determines that the difference is a feature amount of an organic substance, and if the difference is less than the threshold value, the computer system determines that the difference is a feature amount of an inorganic substance. The analysis system according to claim 8, characterized in that.

10. The analysis system further includes an irradiation unit that irradiates an electron beam onto each of the target sample and the reference sample, and the computer system compares the first energy spectrum and the second energy spectrum obtained by irradiating the electron beam at an acceleration voltage of 1 kV or less to determine whether the feature amount in the third energy range is a feature amount of an organic substance. The analysis system according to claim 9, characterized in that.

11. After obtaining the first energy spectrum, the computer system determines whether a feature amount of a transition metal exists in the first energy spectrum before obtaining the second energy spectrum, and if a feature amount of a transition metal exists in the first energy spectrum, the computer system analyzes the elements of the target sample using the second elemental analyzer without obtaining the second energy spectrum. The analysis system according to claim 1, characterized in that.

12. If no feature amount of a transition metal exists in the first energy spectrum, the computer system further determines whether a feature amount of an organic substance or an inorganic substance exists, and if a feature amount of an inorganic substance is detected in the first energy spectrum, the computer system analyzes the elements of the target sample using the second elemental analyzer. The analysis system according to claim 11, characterized in that.

13. The computer system, the first energy spectrum, the second energy spectrum, an observation image of the sample, provides a user interface that presents at least any one of them. The analysis system according to claim 1, characterized in that.

14. The first elemental analyzer is an energy dispersive X-ray analyzer, The second elemental analyzer is an X-ray analyzer using a superconducting transition edge sensor The analysis system according to claim 1, characterized in that

15. An analysis method for analyzing elements contained in a sample, comprising a step of analyzing the elements contained in the sample using the result of detecting X-rays generated from the sample, in the step of analyzing, using a first elemental analyzer, obtaining a first energy spectrum of first X-rays generated from a target sample, in the step of analyzing, using the first elemental analyzer, obtaining a second energy spectrum of second X-rays generated from a reference sample, in the step of analyzing, based on the result of comparing the first energy spectrum and the second energy spectrum, determining whether or not one or more characteristic amounts exist on the first energy spectrum or the second energy spectrum, and if the characteristic amount exists, using a second elemental analyzer having a higher energy resolution than the first elemental analyzer to analyze the elements contained in the target sample The analysis method characterized by the above.

16. An analysis program for causing a computer to execute a process of analyzing elements contained in a sample, causing the computer to execute a step of analyzing the elements contained in the sample using the result of detecting X-rays generated from the sample, in the step of analyzing, causing the computer to execute a step of obtaining a first energy spectrum of first X-rays generated from a target sample using a first elemental analyzer, in the step of analyzing, causing the computer to execute a step of obtaining a second energy spectrum of second X-rays generated from a reference sample using the first elemental analyzer, in the step of analyzing, based on the result of comparing the first energy spectrum and the second energy spectrum, causing the computer to determine whether or not one or more characteristic amounts exist on the first energy spectrum or the second energy spectrum, and if the characteristic amount exists, causing the computer to execute a step of analyzing the elements contained in the target sample using a second elemental analyzer having a higher energy resolution than the first elemental analyzer The analysis program characterized by the above.

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