JP2021032584A - Electron probe micro analyzer - Google Patents

Abstract

To provide an EPMA capable of performing a highly accurate qualitative quantitative analysis.SOLUTION: An element easily dissipated to the outside of a sample by irradiation with an electron beam is selected from an input unit 13 (S10). Further, a trace range specified as a trace element is selected from the input unit 13 from a result of a qualitative quantitative analysis (S20). A data processing unit 11 then executes a pre-measured element measurement process for the element selected in S10 before executing the qualitative quantitative analysis (S30), and further executes the qualitative quantitative analysis process (S40). Next, the data processing unit 11 identifies a trace element included in the trace range set in S20 from the result of the qualitative quantitative analysis, and executes a trace element measurement process for the specified trace element (S50).SELECTED DRAWING: Figure 3

Description

The present invention relates to an electron probe microanalyzer including a wavelength dispersive spectroscope.

As an analyzer that analyzes the composition of the sample surface using a wavelength dispersive spectrometer (WDS), an electron probe microanalyzer (also called an electron probe microanalyzer) is hereinafter referred to as "EPMA (Electron Probe Micro Analyzer)". Is known.). In EPMA, the sample surface is analyzed by analyzing the energy (wavelength) and intensity of the characteristic X-rays emitted when the sample is irradiated with finely squeezed electron beams and the inner shell electrons of the elements contained in the sample transition. It is possible to perform elemental analysis of a minute region in. A device equipped with a WDS in a scanning electron microscope (SEM) is basically the same as a method for analyzing the composition of a sample surface, and the EPMA of the present disclosure includes a device equipped with a WDS in the SEM. It shall be muted.

Japanese Unexamined Patent Publication No. 2010-190810 (Patent Document 1) describes that EPMA performs qualitative analysis or quantitative analysis of elements contained in a sample. In the qualitative analysis, the WDS is roughly scanned in a spectroscopic range, the spectrum of the characteristic X-ray is measured, and the contained element in the sample is identified. Quantitative analysis generally means that for a specific element, the peak profile of the characteristic X-ray of the element is obtained for each of the standard sample and the unknown sample, and the peak intensity is obtained, and the element is obtained from the intensity ratio of the two. It measures the concentration of.

JP-A-2010-190810

From the intensity of the peak of the X-ray spectrum detected in the qualitative analysis, the quantitative value (content) of the element identified in the qualitative analysis can be easily calculated by referring to the standard sensitivity data prepared in advance. .. The analysis in which the qualitative analysis is performed and the quantitative values of the elements identified by the qualitative analysis are also obtained is hereinafter referred to as "qualitative quantitative analysis" to distinguish it from the above-mentioned qualitative analysis and quantitative analysis.

In the qualitative quantitative analysis, in the scannable range (hereinafter referred to as “spectroscopic range”) of the wavelength dispersed by the spectroscope (hereinafter referred to as “spectral wavelength”), the spectral wavelength is predetermined while being changed in predetermined interval steps. It is necessary to measure and record characteristic X-rays over time. Therefore, as a measurement condition, for example, by dividing the spectroscopic range into 4000 steps and setting the counting time of the detector per step (the predetermined time) to 0.09 seconds, the scanning of the spectroscopic range is 360. Complete in seconds.

In qualitative quantitative analysis, the scanning range of the spectral wavelength covers the entire area, compared to quantitative analysis in which scanning of the spectral wavelength and measurement of characteristic X-rays are sufficient for a specific element within the limited range used for the analysis of the element. Therefore, the counting time per scanning step is short. If the counting time per step is short, trace elements cannot be detected. Therefore, in qualitative quantitative analysis, the beam current of the electron beam irradiating the sample is made larger than that in quantitative analysis in order to enable detection of trace elements as well. There is.

However, when the beam current is increased, the energy of the electron beam is increased, which may damage the sample and change the composition of the sample. In particular, alkali metals and halogen elements are likely to dissipate out of the sample by irradiation with a high-energy electron beam. Therefore, when scanning the spectral wavelengths approaches the wavelengths of these elements, these elements have already been dissipated, and the measured intensity may be lower than it should be. As a result, accurate analysis may not be possible, such as the quantitative value being calculated lower than the original value or the peak itself not being detected. In order to avoid such an effect, it is possible to reduce the beam current of the electron beam or widen the beam diameter, but in that case, there arises a problem that trace elements cannot be detected and minute regions cannot be analyzed. ..

Further, in an analyzer equipped with an energy dispersive spectrometer (EDS: Energy Dispersive Spectrometer) (for example, a device equipped with EDS in SEM), a plurality of characteristic X-rays are simultaneously detected by the detector, so that an electron beam is emitted. When the beam current (energy) of the detector is increased, the count value (detection value) of the detector can be saturated, but there is no such concern in the analyzer equipped with WDS. Therefore, in EPMA, the larger the beam current of the electron beam, the larger the count value (detection value) can be obtained, and the more sensitive the analysis becomes possible. However, in the quantitative qualitative analysis, since there is a restriction on the increase of the beam current as described above, it may not be possible to detect or accurately measure trace elements.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an EPMA capable of performing highly accurate qualitative quantitative analysis.

The electron probe microanalyzer (EPMA) according to the first aspect of the present invention includes a wavelength dispersion type spectroscope (WDS) configured to detect characteristic X-rays generated from a sample irradiated with electron beams. It was configured to perform a first process (qualitative quantitative analysis process) to perform a qualitative analysis and obtain a quantitative value of an element identified by the qualitative analysis based on the characteristic X-rays detected by the spectroscope. It is equipped with a processing device. Prior to the execution of the first process, the processing apparatus is to execute the second process (preliminary measurement element measurement process) for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element selected in advance. It is composed of. Then, the processing apparatus is configured to execute the analysis of the selected element by using the measurement result of the second processing.

According to this EPMA, since the second treatment is executed before the execution of the first treatment, the preselected elements are removed from the sample by being irradiated with an electron beam for a long time in the first treatment. Even if the element may be dissipated, the analysis of the element can be performed using the measurement result of the second treatment. For other elements, the first treatment allows the qualitative analysis to be performed and the quantitative values of the elements identified by the qualitative analysis to be obtained.

Further, the electron probe microanalyzer (EPMA) according to the second aspect of the present invention is a wavelength dispersion type spectroscope (WDS) configured to detect characteristic X-rays generated from a sample irradiated with electron beams. And, based on the characteristic X-ray detected by the spectroscope, the qualitative analysis is executed and the first process (qualitative quantitative analysis process) for acquiring the quantitative value of the element identified by the qualitative analysis is executed. It is equipped with a processing device that has been used. The processing apparatus identifies an element whose quantitative value acquired in the first treatment is contained in a predetermined trace range, and acquires the peak intensity of the characteristic X-ray used for the analysis of the specified element. It is configured to perform the process of 3 (trace element measurement process). Then, the processing apparatus is configured to execute the analysis of the specified element by using the measurement result of the third processing.

According to this EPMA, an element whose quantitative value is contained in a trace range is specified from the result of the first treatment, and for the specified element, the analysis of the element is performed using the measurement result of the third treatment. Can be executed. For other elements, the first treatment allows the qualitative analysis to be performed and the quantitative values of the elements identified by the qualitative analysis to be obtained.

According to the above EPMA, highly accurate qualitative quantitative analysis can be performed.

It is a figure which shows the whole structure example of EPMA according to embodiment of this invention. It is a figure which showed an example of the spectrum of the X-ray intensity measured in the qualitative quantitative analysis. It is a flowchart which shows an example of the procedure of the process executed in EPMA according to this embodiment. It is a flowchart which shows an example of the procedure of the pre-measurement element measurement process executed in step S30 of FIG. It is a flowchart which shows an example of the procedure of the qualitative quantitative analysis processing executed in step S40 of FIG. It is a flowchart which shows an example of the procedure of the trace element measurement processing executed in step S50 of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

<Device configuration>
FIG. 1 is a diagram showing an overall configuration example of an EPMA according to an embodiment of the present invention. The EPMA of the present disclosure also includes a device equipped with a WDS in the SEM.

With reference to FIG. 1, the EPMA 100 includes an electron gun 1, a deflection coil 2, an objective lens 3, a sample stage 4, a sample stage drive unit 5, and spectroscopes 6a and 6b. The EPMA 100 further includes a control unit 10, a data processing unit 11, a deflection coil control unit 12, an input unit 13, and a display unit 14. The electron gun 1, the deflection coil 2, the objective lens 3, the sample stage 4, and the spectroscopes 6a and 6b are provided in a measurement chamber (not shown), and the measurement chamber is exhausted to a vacuum state during measurement.

The electron gun 1 is an excitation source that generates an electron beam E irradiated to the sample S on the sample stage 4, and the beam current of the electron beam E can be adjusted by controlling a condensing lens (not shown). it can. The deflection coil 2 forms a magnetic field by the drive current supplied from the deflection coil control unit 12. The electron beam E can be deflected by the magnetic field formed by the deflection coil 2.

The objective lens 3 is provided between the deflection coil 2 and the sample S placed on the sample stage 4, and narrows the electron beam E that has passed through the deflection coil 2 to a minute diameter. The electron gun 1, the deflection coil 2, and the objective lens 3 constitute an irradiation device that irradiates a sample with an electron beam. The sample stage 4 is a stage on which the sample S is placed, and is configured to be movable in a horizontal plane by the sample stage driving unit 5.

By driving the sample stage 4 by the sample stage driving unit 5 and / or driving the deflection coil 2 by the deflection coil control unit 12, the irradiation position of the electron beam E on the sample S can be scanned two-dimensionally. When the scanning range is relatively narrow, scanning by the deflection coil 2 is performed, and when the scanning range is relatively wide, scanning is performed by moving the sample stage 4.

The spectroscopes 6a and 6b are wavelength dispersive spectroscopes (WDS) that detect characteristic X-rays emitted from the sample S irradiated with the electron beam E. In this example, two spectroscopes 6a and 6b are shown, but the number of spectroscopes is not limited to this, and may be one or three or more. The configuration of each spectroscope is the same except for the spectroscopic crystal, and hereinafter, the spectroscopes 6a and 6b may be collectively referred to as "spectrometer 6".

The spectroscope 6a includes a spectroscopic crystal 61a, a detector 63a, and a slit 64a. The irradiation position of the electron beam E on the sample S, the spectroscopic crystal 61a, and the detector 63a are located on a Roland circle (not shown). The spectroscopic crystal 61a is tilted while moving on the straight line 62a by a drive mechanism (not shown), and the detector 63a determines the Bragg diffraction condition by the incident angle of the characteristic X-ray and the emission angle of the diffracted X-ray with respect to the spectroscopic crystal 61a. It rotates as shown in the figure according to the movement of the spectroscopic crystal 61a so as to satisfy the condition. As a result, the wavelength of the characteristic X-ray emitted from the sample S can be scanned.

The spectroscope 6b includes a spectroscopic crystal 61b, a detector 63b, and a slit 64b. Since the configuration of the spectroscope 6b is the same as that of the spectroscope 6a except for the spectroscopic crystal, the description will not be repeated. The configuration of each spectroscope is not limited to the above configuration, and various known configurations can be adopted.

The control unit 10 includes a CPU (Central Processing Unit) 20, a memory (ROM (Read Only Memory) and a RAM (Random Access Memory)) 22, and an input / output buffer (not shown) for inputting / outputting various signals. Consists of including. The CPU expands the program stored in the ROM into a RAM or the like and executes it. The program stored in the ROM is a program in which the processing procedure of the control unit 10 is described. Various tables (maps) used for various operations are also stored in the ROM. The control unit 10 executes various processes in the EPMA 100 according to these programs and tables. The processing is not limited to software, but can also be executed by dedicated hardware (electronic circuit).

The data processing unit 11 is also configured to include a CPU, a memory (ROM and RAM), and an input / output buffer for inputting / outputting various signals (none of which are shown). The data processing unit 11 performs a qualitative analysis on a sample having an unknown composition based on the characteristic X-rays detected by the spectroscope 6 and acquires a quantitative value of an element identified by the qualitative analysis. To execute.

Further, the data processing unit 11 executes a pre-measurement element measurement process for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element before executing the qualitative quantitative analysis for the element selected by the input unit 13. Further, the data processing unit 11 identifies an element whose quantitative value acquired in the qualitative quantitative analysis is contained in a predetermined trace range, and determines the peak intensity of the characteristic X-ray used for the analysis of the specified element for the specified element. Perform the trace element measurement process to be acquired. The qualitative quantitative analysis process (corresponding to the "first process"), the pre-measurement element measurement process (corresponding to the "second process"), and the trace element measurement process (corresponding to the "third process") will be described later. explain in detail.

In addition to the above qualitative quantitative analysis, the data processing unit 11 performs a peak search for characteristic X-rays used for the analysis of the element in the standard sample and the unknown sample containing the element to be analyzed, and quantitative analysis based on this. To do. Although such a quantitative analysis is generally performed in EPMA, this quantitative analysis is not essential in the present invention. The data processing unit 11 may be integrally configured with the control unit 10.

The deflection coil control unit 12 controls the drive current supplied to the deflection coil 2 according to the instruction from the control unit 10. By controlling the drive current according to a predetermined drive current pattern (magnitude and change speed), the irradiation position of the electron beam E can be scanned at a desired scanning speed on the sample S.

The input unit 13 is an operation device for the user to give various instructions to the EPMA 100, and is composed of, for example, a mouse, a keyboard, or the like. In the present embodiment, the element to be measured in the above-mentioned prior measurement element measurement process can be selected from the input unit 13. Further, a trace range for specifying a trace element in the above trace element measurement process can also be set from the input unit 13. These will also be described in detail later.

The display unit 14 is an output device for providing various information to the user, and is composed of, for example, a display provided with a touch panel that can be operated by the user. The touch panel may be used as the input unit 13.

<Explanation of analysis method>
In EPMA 100 according to this embodiment, qualitative quantitative analysis is performed. In the qualitative quantitative analysis, the spectrum of the characteristic X-ray over the entire spectroscopic range is measured by detecting the intensity of the characteristic X-ray while changing the spectral wavelength at predetermined intervals, and the element is identified from the wavelength having the peak. Further, the quantitative value (content) of the identified element is calculated by obtaining the intensity of the detected peak and comparing it with the standard sensitivity data prepared in advance.

As a measurement condition, for example, by dividing the spectroscopic range into 4000 steps and setting the counting time of the detector per step to 0.09 seconds, scanning of the spectroscopic range can be completed in 360 seconds. In qualitative quantitative analysis, since the scanning range of the spectral wavelength covers the entire area, it is sufficient to perform measurement by scanning the spectral wavelength in a limited range (for example, several tens of steps) used for the analysis of the specific element. Compared to the analysis, the counting time per step is short. In the quantitative analysis, for example, the counting time of the detector per step can be set to 1.0 second.

If the counting time per step is short, trace elements cannot be measured. Therefore, in qualitative quantitative analysis, the beam current of the electron beam irradiating the sample is increased in order to enable measurement of trace elements as well.

However, when the beam current is increased in the qualitative quantitative analysis, the following problems occur. That is, the sample may be damaged due to the increase in the energy of the electron beam, and the composition of the sample may change. In particular, alkali metals such as Na and K and halogen elements such as Cl and F are likely to dissipate to the outside of the sample by irradiation with a high-energy electron beam. Therefore, when scanning the spectral wavelengths approaches the wavelengths of these elements, the measured intensities may be lower than they should be because these elements have already been dissipated. As a result, accurate analysis may not be possible, for example, the quantitative values for these elements may be calculated lower than they should be, or the peaks themselves may not be detected.

FIG. 2 is a diagram showing an example of a spectrum of X-ray intensity measured in qualitative quantitative analysis. (A) is a spectrum when the beam current I of the electron beam is I1, and (b) is a spectrum when the beam current I of the electron beam is I2 (I2> I1). In this example, the case of I1 = 20nA (ampere) and I2 = 100nA is shown. The horizontal axis shows the spectral wavelength, and the vertical axis shows the count value (cps) at the detector. In both (a) and (b), the counting time per scanning step is the same.

With reference to FIG. 2A, when the beam current I of the electron beam is I1, the alkali metal potassium (K) is detected in the wavelength range of 3.0A (angstrom) to 4.0A. There is.

On the other hand, referring to FIG. 2B, when the beam current I of the electron beam is I2 (I2> I1), the wavelength is 3.0A (Angstrom) to 4 even though the beam current I is large. No potassium (K) was detected in the range of 0.0A. This is because potassium (K) has already dissipated out of the sample when the scanning of the spectral wavelength approaches 3.0A to 4.0A due to the increase in the beam current I. For other elements, the X-ray intensity also increases as the beam current I increases.

As described above, in the qualitative quantitative analysis, when the beam current I of the electron beam is increased in order to compensate for the short counting time per scanning step, if the sample contains alkali metals or halogen elements, they are used. Elements are scattered out of the sample, making it impossible to perform accurate analysis on these elements.

Therefore, in order to avoid the above-mentioned effects, the beam current of the electron beam may be lowered or the beam diameter may be widened. However, if the beam current is lowered, trace elements may not be detected, and if the beam diameter of the electron beam is widened, there arises a problem that analysis of a minute region cannot be performed.

Therefore, in the EPMA 100 according to the present embodiment, the peak intensity of the characteristic X-ray used for the analysis of the element selected in advance is acquired for the element selected in advance before the execution of the qualitative quantitative analysis (“preliminary measurement element measurement process” described later). "). The preselected elements are alkali metals and halogen elements. Then, for the selected element, the measurement result of the prior measurement element measurement process is adopted in preference to the measurement result of the qualitative quantitative analysis process, and the element is analyzed using the measurement result of the prior measurement element measurement process. ..

As a result, when the beam current I of the electron beam is increased in the qualitative quantitative analysis, the element that is dissipated by the irradiation of the electron beam is also analyzed using the measurement result of the prior measurement element measurement process. Can be done. For other elements, by increasing the beam current I and performing qualitative quantitative analysis, the elements in the sample can be identified and the quantitative values of the identified elements can be obtained.

Further, in an analyzer equipped with EDS (for example, a device equipped with EDS in SEM), a plurality of characteristic X-rays are simultaneously detected by the detector. Therefore, when the beam current (energy) of the electron beam is increased, the detector is used. In EPMA with WDS, there is no such concern, where the counts of can be saturated. Therefore, in EPMA, the larger the beam current of the electron beam, the larger the count value can be obtained, and the more sensitive the analysis becomes. However, in the quantitative qualitative analysis, as described above, since there is a restriction on the increase of the beam current in order to suppress the dissipation of the alkali metal or halogen element in the sample to the outside of the sample, the detection and accurate measurement of trace elements May not be possible.

Therefore, in the EPMA 100 according to the present embodiment, an element whose quantitative value is contained in a predetermined trace range is further specified from the result of the qualitative quantitative analysis, and the characteristic X-ray used for the analysis of the specified element is obtained. The peak intensity of is obtained (“trace element measurement processing” described later). The trace range can be, for example, a quantitative value in the range of 0.05% to 1.0%, but is not limited to this range. Then, for the specified element, the measurement result of the trace element measurement process is adopted in preference to the measurement result of the qualitative quantitative analysis process, and the analysis of the element is executed using the measurement result of the trace element measurement process.

As a result, even for trace elements, the analysis of the trace elements can be performed using the measurement results of the trace element measurement process. For other elements, the qualitative analysis can be performed by the qualitative quantitative analysis, and the quantitative values of the elements identified by the qualitative analysis can be obtained.

In the EPMA 100 according to this embodiment, the counting time per scanning step in the trace element measurement processing is longer than the counting time per step in the qualitative quantitative analysis. As a result, it is possible to obtain an accurate quantitative value for trace elements.

In the present embodiment, since the beam current of the electron beam is increased in the qualitative quantitative analysis, the detection sensitivity of trace elements in the qualitative quantitative analysis is increased. However, in qualitative quantitative analysis, increasing the beam current of the electron beam may damage the sample, so there are some restrictions on the beam current, and the counting time per scanning step is short, so the amount is very small. It may not be possible to obtain highly accurate measurement results for elements. According to the present embodiment, it is possible to obtain an accurate quantitative value by executing the trace element measurement process for the trace element identified by the qualitative quantitative analysis.

FIG. 3 is a flowchart showing an example of a processing procedure executed in the EPMA 100 according to this embodiment.

With reference to FIG. 3, first, an element to be measured in advance by a preliminary measurement element measurement process (described later) is selected before the execution of the qualitative quantitative analysis process (described later) (step S10). In the present embodiment, the user can select the element from the input unit 13, and the alkali metal and halogen elements are displayed on the input unit 13 by default. The selected element is stored in the memory of the control unit 10 or the data processing unit 11. In addition, instead of leaving the selection of the element to be measured in advance to the user, for example, the alkali metal and the halogen element may be automatically selected.

Next, a range of quantitative values (trace range) for selecting a trace element to be measured by the trace element measurement process (described later) is set from the measurement result of the qualitative quantitative analysis process (step S20). In the present embodiment, the user can set the range from the input unit 13, and the input unit 13 displays, for example, 0.05% to 1.0% as a trace range by default. The set range is stored in the memory of the control unit 10 or the data processing unit 11. In addition, instead of leaving the setting of a minute range to the user, for example, the above range may be set automatically.

When the element to be measured by the preceding measurement element measurement process is selected and the trace range used in the trace element measurement process is set, the data processing unit 11 responds to the measurement start instruction from the input unit 13 or the like in step S10. The pre-measured element measurement process is executed for the element selected in (step S30). By this pre-measurement element measurement process, the peak intensity used for the analysis of the element selected in step S10 is acquired, and the quantitative value is calculated. The measurement result of the prior measurement element measurement process including the calculated quantitative value is stored in the memory of the data processing unit 11. The details of the pre-measurement element measurement process will be described in detail later.

When the pre-measurement element measurement process is completed, the data processing unit 11 executes the qualitative quantitative analysis process (step S40). By this qualitative quantitative analysis process, the element contained in the sample S is identified, and the quantitative value of the identified element is calculated. In this qualitative quantitative analysis process, since the counting time per step is short in order to scan the entire spectroscopic range, the beam current I of the electron beam is made larger than that at the time of executing the pre-measured element measurement process. .. The measurement result of the qualitative quantitative analysis process including the identified element and its quantitative value is also stored in the memory of the data processing unit 11. The details of the qualitative quantitative analysis process will be described in detail later.

When the qualitative quantitative analysis process is executed, the data processing unit 11 executes the trace element measurement process for the trace elements contained in the trace range set in step S20 (step S50). By this trace element measurement process, the peak intensity used for the analysis of the selected trace element is acquired, and the quantitative value of the trace element is calculated.

In this trace element measurement process, the counting time per scanning step is longer than the counting time at the time of executing the qualitative quantitative analysis process. This makes it possible to calculate accurate quantitative values for trace elements. The measurement result of the trace element measurement process including the calculated quantitative value of the trace element is also stored in the memory of the data processing unit 11. The details of the trace element measurement process will be described in detail later.

Then, the data processing unit 11 overwrites the measurement result of the qualitative quantitative analysis process with the measurement result of the trace element measurement process (step S60). That is, for the trace elements selected based on the set trace range, the measurement result of the trace element measurement process is preferentially adopted over the measurement result of the qualitative quantitative analysis process. As a result, highly accurate quantitative values can be obtained for trace elements.

Further, the data processing unit 11 further overwrites the measurement result of the qualitative quantitative analysis process with the measurement result of the trace element measurement process with the measurement result of the prior measurement element measurement process (step S70). That is, the measurement result of the prior measurement element measurement process is adopted with higher priority than the measurement result of the qualitative quantitative analysis process and the trace element measurement process. As a result, a highly accurate quantitative value can be obtained for the element (alkali metal or halogen element) selected in step S10.

FIG. 4 is a flowchart showing an example of the procedure of the pre-measurement element measurement process executed in step S30 of FIG.

With reference to FIG. 4, the control unit 10 sets the beam current I of the electron beam to I1 (step S110). The value I1 is, for example, equivalent to the magnitude of the beam current set when performing a quantitative analysis (not shown).

Next, the data processing unit 11 sets the target element for which the prior measurement is to be performed (step S120). Specifically, the data processing unit 11 selects and sets one of the elements selected in step S10 of FIG.

Subsequently, the data processing unit 11 sets the measurement conditions of the target element set in step S120 (step S130). Specifically, the spectral wavelengths for each element are tabulated or mapped in advance and stored in the memory, and the spectral wavelengths associated with the target element set in step S120 are read out. Then, the wavelength range for scanning is set based on the read spectral wavelength, and the counting time per scanning step is set. As for the wavelength range to be scanned, for example, a range of about 40 steps is set around the read spectral wavelength. The counting time per step is set longer than the counting time (described later) in the qualitative quantitative analysis process, and is uniformly set to 1.0 second for all elements, for example.

Next, the data processing unit 11 executes spectral measurement for the target element according to the measurement conditions set in step S130 (step S140), and acquires the peak profile of the target element. Then, the data processing unit 11 acquires the peak intensity from the acquired peak profile (step S150), and calculates the quantitative value of the target element by referring to the standard sensitivity data prepared in advance (step S160). The standard sensitivity data is tabulated in advance for each element and stored in the memory.

When the quantitative value of the target element is calculated, the data processing unit 11 confirms whether or not there is another element in the element selected in step S10 of FIG. 3 (step S170). If there are other selected elements (YES in step S170), the process is returned to step S120. In this way, the processes of steps S120 to S160 are executed for all the elements selected in step S10 of FIG. 3, and the quantitative values are calculated.

FIG. 5 is a flowchart showing an example of the procedure of the qualitative quantitative analysis process executed in step S40 of FIG.

With reference to FIG. 5, the control unit 10 sets the beam current I of the electron beam to I2 (step S210). The value I2 is larger than the value I1 set at the time of executing the above-mentioned prior measurement element measurement process. This enhances the detection sensitivity of trace elements. On the other hand, although alkali metals and halogen elements can be dissipated to the outside of the sample by increasing the beam current I of the electron beam, these elements are selected in step S10 of FIG. 3 for qualitative quantitative analysis. It can be measured in the pre-measurement element measurement process before the execution of the process.

Next, the data processing unit 11 sets the measurement conditions for the qualitative quantitative analysis process (step S220). Specifically, the number of step divisions in the spectroscopic range is set, and the counting time per scanning step is set. The number of step divisions in the spectroscopic range is set to, for example, 4000 steps. The counting time per step is set shorter than the counting time in the pre-measured element measurement process, for example, 0.09 seconds.

Next, the data processing unit 11 executes the qualitative quantitative analysis according to the measurement conditions set in step S220 (step S230). Specifically, with respect to the spectroscopic range, the spectral wavelength is changed from the long wavelength side, for example, with a step width determined by the number of step divisions, and in each step, characteristic X-rays are measured for a set counting time. In this example, the measurement of 0.09 seconds for each step is performed in 4000 steps, so that the scanning of the entire range is completed in 360 seconds.

Then, the data processing unit 11 identifies the contained element from the peak wavelength of the obtained X-ray spectrum. Further, the data processing unit 11 acquires the peak profile of the identified element and acquires the peak intensity from the acquired peak profile. Then, the data processing unit 11 reads the standard sensitivity data prepared in advance from the memory and compares the peak intensity of the identified element with the standard sensitivity data to calculate the quantitative value of the identified element (step S240). ).

FIG. 6 is a flowchart showing an example of the procedure of the trace element measurement process executed in step S50 of FIG.

With reference to FIG. 6, the data processing unit 11 selects the elements identified in the qualitative quantitative analysis process whose quantitative values calculated in the process are included in the trace range set in step S20 of FIG. Identify (step S310). The trace range is, for example, a quantitative value in the range of 0.05% to 1.0%. The lower limit of 0.05% is set so as not to detect noise, and is appropriately set according to the magnitude of noise.

Next, the data processing unit 11 confirms the presence or absence of an element whose quantitative value is contained in a trace range (step S320). If there is no such element (NO in step S320), the subsequent series of processes are not executed and the process is transferred to the return.

When there is an element whose quantitative value is contained in a trace range (YES in step S320), the control unit 10 sets the beam current I of the electron beam to I1 (step S330). In this example, the magnitude of the beam current I in the trace element measurement process is the same as the magnitude of the beam current I in the prior measurement element measurement process described with reference to FIG. 4, but it is not necessarily the same.

Next, the data processing unit 11 sets the target element to be measured (step S340). Specifically, the data processing unit 11 selects and sets one of the elements specified in step S310. Subsequently, the data processing unit 11 sets the measurement conditions of the target element set in step S340 (step S350).

The processes of steps S330 to S390 are the same as the processes of steps S110 to S170 shown in FIG. 4, respectively, and the description is duplicated, so the description is not repeated.

Then, the processes of steps S340 to S380 are executed for all the elements specified in step S310, and the quantitative values are calculated.

As described above, in this embodiment, the pre-measured element measurement process is executed for the element selected in the input unit 13 before the execution of the qualitative quantitative analysis process. Therefore, the selected element is qualitatively quantified. Even for elements (alkali metals and halogen elements) that may be dissipated to the outside of the sample due to long-term irradiation with electron beams in the analysis, the analysis of the elements is performed using the measurement results of the prior measurement element measurement process. Can be executed.

Further, in this embodiment, an element whose quantitative value is included in a trace range is specified from the result of the qualitative quantitative analysis process, and the specified element is the element using the measurement result of the trace element measurement process. Analysis can be performed. For other elements, the qualitative analysis can be performed by the qualitative quantitative analysis process, and the quantitative values of the elements identified by the qualitative analysis can be obtained.

[Aspect]
It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following embodiments.

(Item 1) The EPMA according to one embodiment includes a wavelength dispersive spectroscope configured to detect characteristic X-rays generated from a sample irradiated with electron beams, and characteristic X-rays detected by the spectroscope. Based on the above, the processing apparatus is configured to perform a qualitative analysis and perform a first process for obtaining a quantitative value of an element identified by the qualitative analysis. The processing apparatus is configured to execute a second process for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element selected in advance before executing the first process. Then, the processing apparatus is configured to perform the analysis of the selected element using the measurement result of the second processing.

According to the EPMA of the first item, even if the element selected in advance may be dissipated to the outside of the sample by being irradiated with an electron beam for a long time in the first treatment, the second treatment is performed. The analysis of the element can be carried out using the measurement result of. For other elements, the first treatment allows the qualitative analysis to be performed and the quantitative values of the elements identified by the qualitative analysis to be obtained.

(Item 2) In the EPMA described in item 1, the processing apparatus performs measurement at predetermined time intervals while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals. It is configured as follows. The predetermined time in the second process is longer than the predetermined time in the first process.

According to the EPMA of the second term, a highly accurate measurement result can be obtained by the second treatment for the element selected in advance.

(Term 3) In the EPMA described in the first or second process, the beam current of the electron beam at the time of executing the first process is larger than the beam current of the electron beam at the time of executing the second process.

According to the EPMA of the third item, in the first process, even minute elements can be detected without extending the measurement time.

(Clause 4) In the EPMA described in paragraph 1, the processing apparatus further identifies an element whose quantitative value acquired in the first processing is contained in a predetermined trace range, and with respect to the specified element. It is configured to perform a third process of acquiring the peak intensity of the characteristic X-rays used in the analysis of the element. Then, the processing apparatus is configured to execute the analysis of the specified element using the measurement result of the third processing.

According to the EPMA of the fourth item, an element whose quantitative value is included in a trace range is specified, and for the specified element, the analysis of the element can be performed using the measurement result of the third treatment. ..

(Item 5) In the EPMA according to the item 4, the processing apparatus performs measurement at predetermined time intervals while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals. It is configured as follows. The predetermined time in the third process is longer than the predetermined time in the first process.

According to the EPMA of the fifth item, highly accurate measurement results can be obtained by the third treatment for the specified trace elements.

(Section 6) In the EPMA according to the fourth or fifth treatment, the processing apparatus obtains the measurement result of the second treatment for the element whose peak intensity was acquired in both the second and third treatments. It is configured to be used to perform an analysis of the element.

According to the EPMA of paragraph 6, for the identified trace elements, the analysis of the element can be performed using the measurement result of the third treatment, and for the preselected element, the second treatment. The analysis of the element can be carried out using the measurement result of. For other elements, the first treatment allows the qualitative analysis to be performed and the quantitative values of the elements identified by the qualitative analysis to be obtained.

(Section 7) In the EPMA according to any one of paragraphs 1 to 6, the selected element is an element belonging to an alkali metal or halogen element.

Elements belonging to alkali metals or halogen elements are likely to dissipate to the outside of the sample by irradiation with an electron beam. However, according to EPMA of the seventh item, the analysis of these elements can be carried out by the second treatment.

(Item 8) In the EPMA according to any one of the items 1 to 6, the EPMA further includes an input device for the user to select an element on which the second process is performed.

According to the EPMA of the seventh item, the user can select the element for which the analysis is performed in the second process.

(Section 9) EPMA according to another aspect includes a wavelength dispersive spectroscope configured to detect characteristic X-rays generated from a sample irradiated with electron beams, and characteristic X detected by the spectroscope. It comprises a processing apparatus configured to perform a qualitative analysis based on the line and to perform a first process of obtaining a quantitative value of an element identified by the qualitative analysis. The processing apparatus identifies an element whose quantitative value acquired in the first treatment is contained in a predetermined trace range, and acquires the peak intensity of the characteristic X-ray used for the analysis of the specified element. It is configured to execute the process of 3. Then, the processing apparatus is configured to execute the analysis of the specified element using the measurement result of the third processing.

According to the EPMA of the ninth item, an element whose quantitative value is included in a trace range is specified from the result of the first treatment, and for the specified element, the element is concerned using the measurement result of the third treatment. Analysis can be performed. For other elements, the first treatment allows the qualitative analysis to be performed and the quantitative values of the elements identified by the qualitative analysis to be obtained.

(Item 10) In the EPMA according to the item 9, the processing apparatus performs measurement at predetermined time intervals while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals. It is configured as follows. The predetermined time in the third process is longer than the predetermined time in the first process.

According to the EPMA of the tenth item, a highly accurate measurement result can be obtained by the third treatment for the specified trace element.

(11) In the EPMA according to paragraph 9 or 10, the EPMA further comprises an input device for the user to set a trace range.

According to the EPMA of the eleventh item, the user can select a trace range to be specified as a trace element.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the embodiment described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Electron gun, 2 Deflection coil, 3 Objective lens, 4 Sample stage, 5 Sample stage drive unit, 6, 6a, 6b spectrometer, 10 Control unit, 11 Data processing unit, 12 Deflection coil control unit, 13 Input unit, 14 Display, 61a, 61b spectroscopic crystal, 63a, 63b detector, 64a, 64b slit, 100 EPMA, E electron beam, S sample.

Claims (11)

A wavelength dispersive spectroscope configured to detect characteristic X-rays generated from a sample irradiated with an electron beam, and
A processing apparatus configured to perform a qualitative analysis based on the characteristic X-rays detected by the spectroscope and to perform a first process for obtaining a quantitative value of an element identified by the qualitative analysis. Prepare,
The processing device is
Prior to the execution of the first treatment, the second treatment for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element selected in advance is executed.
For the selected element, an electron probe microanalyzer configured to perform an analysis of the element using the measurement result of the second process. The processing device is configured to perform measurement for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals.
The electron beam microanalyzer according to claim 1, wherein the predetermined time in the second process is longer than the predetermined time in the first process. The electron beam microanalyzer according to claim 1 or 2, wherein the beam current of the electron beam at the time of executing the first process is larger than the beam current of the electron beam at the time of executing the second process. .. The processing device further
The elements whose quantitative values obtained in the first treatment are contained in a predetermined trace range are identified, and the elements are identified.
For the specified element, a third process for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element is executed.
The electron probe microanalyzer according to claim 1, wherein the specified element is configured to perform an analysis of the element using the measurement result of the third process. The processing device is configured to perform measurement for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals.
The electron beam microanalyzer according to claim 4, wherein the predetermined time in the third process is longer than the predetermined time in the first process. The processing apparatus is configured to perform analysis of the element for which the peak intensity has been acquired in both the second and third treatments, using the measurement result of the second treatment. , The electron probe microanalyzer according to claim 4 or 5. The electron probe microanalyzer according to any one of claims 1 to 6, wherein the selected element is an element belonging to an alkali metal or halogen element. The electron beam microanalyzer according to any one of claims 1 to 6, further comprising an input device for the user to select an element in which the second process is performed. A wavelength dispersive spectroscope configured to detect characteristic X-rays generated from a sample irradiated with an electron beam, and
A processing apparatus configured to perform a qualitative analysis based on the characteristic X-rays detected by the spectroscope and to perform a first process for obtaining a quantitative value of an element identified by the qualitative analysis. Prepare,
The processing device is
The elements whose quantitative values obtained in the first treatment are contained in a predetermined trace range are identified, and the elements are identified.
For the specified element, a third process for acquiring the peak intensity of the characteristic X-ray used for the analysis of the element is executed.
For the identified element, an electron probe microanalyzer configured to perform an analysis of the element using the measurement result of the third process. The processing device is configured to perform measurement for a predetermined time while operating the spectroscope so that the wavelength of the characteristic X-ray detected by the spectroscope changes at predetermined intervals.
The electron beam microanalyzer according to claim 9, wherein the predetermined time in the third process is longer than the predetermined time in the first process. The electron beam microanalyzer according to claim 9 or 10, further comprising an input device for setting the trace range by the user.

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