JP2023086588A - Electron beam probe microanalyzer, epma data correction method, and epma data correction program - Google Patents

Abstract

To provide an EPMA that can perform mapping analysis using a beam scan method over a wider range than before.SOLUTION: An EPMA 1 comprises: a sample stage 11 on which a sample is mounted; an electron beam source 12 that irradiates the sample with an electron beam; an electromagnetic field source 13 that controls the direction of the electron beam so that the irradiation position of the electron beam moves within a predetermined scan range; an analyzing crystal 15 that divides a characteristic X-ray emitted from the sample; an X-ray detector 16 that has a slit 161 and an X-ray detection unit 162; a standard sample intensity distribution value storage unit 32 that stores a standard sample intensity distribution value being the intensity of the characteristic X-ray generated at each position within the scan range of a standard sample; a sample-to-be-measured intensity distribution value acquisition unit 33 that acquires a sample-to-be-measured intensity distribution value being the intensity of the characteristic X-ray generated at each position of a sample to be measured; and a post-correction sample-to-be-measured intensity distribution value calculation unit 34 that calculates a post-correction sample-to-be-measured intensity distribution value obtained by correcting the sample-to-be-measured intensity distribution value by using the standard sample intensity distribution value.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electron probe microanalyzer (hereinafter abbreviated as "EPMA" according to common practice), a correction method for EPMA data (data obtained by EPMA), and an EPMA data correction program.

In EPMA, a sample is irradiated with an electron beam focused to a small diameter, and characteristic X-rays emitted from the irradiated position are detected. Since the characteristic X-rays have wavelengths specific to the elements contained in the sample, by analyzing the wavelength and intensity of the characteristic X-rays, it is possible to identify and quantify the elements present in the vicinity of the analysis position on the sample.

Analysis of the wavelength and intensity of characteristic X-rays is generally performed using an analyzing crystal that disperses incident X-rays and an X-ray detector that detects the spectrally dispersed characteristic X-rays. The irradiation position of the electron beam on the sample, the analyzing crystal, and the X-ray detector each form a "Roland circle" so that the characteristic X-rays emitted from the irradiation position are separated by the analyzing crystal and enter the X-ray detector. are placed at predetermined positions on the circumference of a circle called A slit is provided in the X-ray detector to improve the wavelength resolution. Further, by providing a plurality of analyzing crystals with different wavelengths to be detected and providing an X-ray detector in each of the plurality of analyzing crystals, it is possible to simultaneously measure a plurality of types of characteristic X-rays with different wavelengths, It is thereby possible to identify and quantify a plurality of different elements.

In EPMA, by repeating the same analysis while moving the irradiation position of the electron beam within a predetermined one-dimensional range or two-dimensional range on the sample, the type and content of the element at each position can be examined. , on the basis of which the distribution of elements over the range can be obtained. Although one-dimensional range analysis is generally referred to as line analysis and two-dimensional range analysis is referred to as mapping analysis, they are collectively referred to herein as mapping analysis.

There are two methods for moving the electron beam irradiation position: the stage scanning method, in which the electron beam is fixed and the sample stage is moved; There are two methods, a beam scanning method that allows the light to flow (see, for example, Patent Document 1). Among these methods, the beam scanning method is superior to the stage scanning method in that the electron beam irradiation position can be scanned at high speed. In addition, since the stage scanning method moves the sample stage mechanically, there is a problem that the irradiation position must be confirmed for each line scanning in consideration of the influence of backlash.

Japanese Patent Application Laid-Open No. 2021-32584

In mapping analysis by the conventional beam scanning method, if the range of movement of the irradiation position of the electron beam is increased, depending on the irradiation position, part of the characteristic X-ray of a predetermined wavelength emitted from the irradiation position and dispersed by the analyzing crystal deviates from the slit and does not enter the X-ray detector, resulting in an error in the detected intensity of characteristic X-rays. For this reason, in conventional mapping analysis, beam scanning analysis can only be performed within a range in which all characteristic X-rays of a predetermined wavelength separated by the analyzing crystal pass through the slit. When it was done, it had to be analyzed by the time-consuming stage scanning method.

The problem to be solved by the present invention is to provide an EPMA, an EPMA data correction method, and an EPMA data correction program that can perform mapping analysis using a beam scanning method over a wider range than before.

The EPMA according to the present invention, which has been made to solve the above problems,
a sample stage on which the sample is placed;
an electron beam source for irradiating the sample placed on the sample stage with an electron beam;
an electromagnetic field source for generating one or both of an electric field and a magnetic field for controlling the direction of the electron beam so that the irradiation position of the electron beam moves within a predetermined scanning range;
an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage;
an X-ray detector having a slit for passing characteristic X-rays spectroscopically separated by the analyzing crystal and detecting the characteristic X-rays that have passed through the slit;
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value storage unit for storing standard sample intensity distribution values, which are the intensity of characteristic X-rays detected by a detector and generated at each position within the scanning range of the standard sample;
A characteristic X generated at each position of the sample to be measured placed on the sample stage and detected by the X-ray detector while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a measurement target sample intensity distribution value acquisition unit that acquires a measurement target sample intensity distribution value that is the line intensity;
Corrected measurement target sample intensity obtained by correcting the measurement target sample intensity distribution value acquired by the measurement target sample intensity distribution value acquisition unit using the standard sample intensity distribution value read from the standard sample intensity distribution value storage unit and a post-correction measurement target sample intensity distribution value calculation unit that calculates the distribution value.

EPMA data correction method according to the present invention,
a sample stage on which a sample is placed; an electron beam source for irradiating the sample placed on the sample stage with an electron beam; an electromagnetic field source that generates one or both of an electric field and a magnetic field that control the direction of the; an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage; and an X-ray detector for detecting the characteristic X-rays that have passed through the slit, the EPMA comprising:
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value and a post-correction measurement target sample intensity distribution value calculation step of calculating the value.

An EPMA data correction program according to the present invention includes a sample stage on which a sample is placed, an electron beam source for irradiating the sample placed on the sample stage with an electron beam, and a predetermined scanning position of the electron beam. An electromagnetic field source that generates one or both of an electric field and a magnetic field that controls the direction of the electron beam so that it moves within a range; and an X-ray detector having a slit for passing characteristic X-rays dispersed by the analyzing crystal and detecting the characteristic X-rays that have passed through the slit. a program,
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value and a post-correction measurement target sample intensity distribution value calculation step of calculating the value.

In the EPMA, EPMA data correction method, and EPMA data correction program according to the present invention, a standard sample in which a predetermined element is uniformly distributed within a scanning range is used, and the irradiation position of the electron beam is moved within the scanning range. A standard sample intensity value at each location within the scan range is used as detected by the X-ray detector. Since characteristic X-rays with substantially the same intensity are emitted from such a standard sample regardless of the position within the scanning range, the standard sample intensity value for each position is is a value that reflects the rate of detection by the X-ray detector. By correcting the intensity value of the sample to be measured using this standard sample intensity value, even at positions in the sample to be measured where part of the emitted characteristic X-rays does not pass through the slit, the emitted characteristic X-ray The intensity of the line can be determined accurately. Therefore, accurate data can be obtained even if a part of the characteristic X-rays includes a scanning range that does not pass through the slit, so that mapping analysis using beam scanning can be performed over a wider range than before. .

1 is a schematic configuration diagram showing an embodiment of an EPMA according to the present invention; FIG. FIG. 2 is a top view showing the configuration of scanning coils in the EPMA of this embodiment; FIG. 2 is a top view showing the arrangement of a plurality of analyzing crystals and X-ray detectors in the EPMA of this embodiment; 4 is a flowchart showing the operation of the EPMA of this embodiment; FIG. 4 is a schematic diagram showing a state in which characteristic X-rays pass through a slit; FIG. 4 is a schematic diagram showing a state in which a part of characteristic X-rays is blocked by a slit; FIG. 4 is a diagram schematically showing measurement results of the intensity distribution of characteristic X-rays emitted from each position on the surface of a standard sample; FIG. 4 is a schematic diagram before correction of the measurement result of the intensity distribution of characteristic X-rays emitted from each position on the surface of the measurement target sample; FIG. 4 is a schematic diagram of the distribution of correction coefficients obtained based on the measurement result of the intensity distribution of characteristic X-rays emitted from each position on the surface of the standard sample; FIG. 4 is a schematic diagram of corrected measurement results of the intensity distribution of characteristic X-rays emitted from each position on the surface of the sample to be measured. FIG. 4 is a diagram schematically showing another example of the measurement result of the intensity distribution of characteristic X-rays emitted from each position on the surface of the standard sample; FIG. 5 is a schematic diagram of the distribution of correction coefficients obtained based on another example of the measurement result of the intensity distribution of characteristic X-rays emitted from each position on the surface of the standard sample;

An embodiment of the EPMA and data correction method according to the present invention will be described with reference to FIGS. 1 to 12. FIG.

(1) Configuration of one embodiment of EPMA according to the present invention As shown in FIG. , a scanning coil (corresponding to the electromagnetic field source) 13 , an objective lens 14 , an analyzing crystal 15 , an X-ray detector 16 and a stage driving mechanism 17 .

The electron gun 12 generates and emits an electron beam 91 and is arranged so that the emitted electron beam 91 is directed toward the sample stage 11 .

A scanning coil 13 is arranged between the sample stage 11 and the electron gun 12 . As shown in FIG. 2, the scanning coil 13 is a combination of a first coil 131, a second coil 132, a third coil 133 and a fourth coil . The first coil 131 and the second coil 132 are arranged coaxially on the first axis 1301 . The third coil 133 and the fourth coil 134 are arranged so as to be coaxial about a second axis 1302 perpendicular to the first axis 1301 across a space sandwiched between the first coil 131 and the second coil 132. . Both the first axis 1301 and the second axis 1302 are perpendicular to the traveling direction of the electron beam 91 emitted from the electron gun 12 (the traveling direction of which is not bent by the scanning coil 13). Hereinafter, the direction in which the first axis 1301 extends is defined as the X direction, the direction in which the second axis 1302 extends is defined as the Y direction, and the traveling direction of the electron beam 91 is defined as the Z direction.

The objective lens 14 is provided between the scanning coil 13 and the sample stage 11 and functions as a lens that converges the electron beam that has passed through the scanning coil 13 on the sample stage 11 .

The analyzing crystal 15 disperses X-rays having a predetermined wavelength incident on a cylindrical concave surface having a predetermined curvature. The concave surfaces have the same cross-sectional shape with respect to the direction perpendicular to the page of FIG. Although only one analyzing crystal 15 is shown in FIG. 1, actually, as shown in FIG. A crystal 15 is arranged around an axis in the Z direction.

The X-ray detector 16 has a slit 161 and an X-ray detector 162 , and the X-ray detector 162 detects X-rays that have passed through the slit 161 . The slit 161 has a linear hole extending in a direction perpendicular to the paper surface of FIG. One X-ray detector 16 is provided for one analyzing crystal 15 (that is, the same number as the analyzing crystals 15). The plurality of sets of analyzing crystals 15 and X-ray detectors 16 are arranged so that each set disperses X-rays of mutually different wavelengths with the analyzing crystals 15 and makes them enter the X-ray detectors 16 .

Each analyzing crystal 15 and the slit 161 of the X-ray detector 16 provided corresponding thereto is a Rowland circle (chain line in FIG. 1) having a circumference corresponding to the wavelength of X-rays to be dispersed and detected. The Rowland circle is set for each analyzing crystal 15.). Each analyzing crystal 15 and each X-ray detector 16 are arranged so that the circumference of each Rowland circle passes through a common point near the center of the sample stage 11 .

The stage drive mechanism 17 moves the sample stage 11 in the X, Y, and Z directions, and is used to set the initial position of the sample 90 on the sample stage 11 . In general EPMA, a stage driving mechanism is used to move the electron beam irradiation position on the sample during stage scanning, but in this embodiment, the stage driving mechanism 17 does not need to have a stage scanning function. However, the stage driving mechanism 17 may also have a stage scanning function after allowing the user to select either beam scanning or stage scanning.

The EPMA 1 of this embodiment further has a control section 20 and a data processing section 30 . The control unit 20 and the data processing unit 30 are embodied by hardware such as a CPU and memory, and software.

The control unit 20 controls operations of the electron gun 12 , the scanning coil 13 and the stage driving mechanism 17 . The control unit 20 also has a function of transmitting, as control information for the scanning coil 13 , information on the position on the sample 90 irradiated with the electron beam to the data processing unit 30 .

The data processing unit 30 includes a standard sample intensity distribution value acquisition unit 31, a standard sample intensity distribution value storage unit 32, a measurement target sample intensity distribution value acquisition unit 33, and a measurement target sample intensity distribution value calculation unit after correction 34. have. The details of each part in the data processing part 30 will be described later together with the explanation of the operation of the EPMA 1 of this embodiment.

(2) The operation of the EPMA of this embodiment and an embodiment of the EPMA data correction method according to the present invention will be described with reference to FIGS. Description will be made including the form.

A user places a standard sample on the upper surface of the sample stage 11 (step 1: FIG. 4) and performs a predetermined measurement start operation. This starts a series of operations of EPMA1. Here, the standard sample is a sample in which a predetermined element is uniformly distributed within a scanning range in which the electron beam emitted from the electron gun 12 moves on the surface of the standard sample by the operation of the scanning coil 13 . As the predetermined element, an element assumed to be contained in the measurement target sample to be measured later is used.

First, the controller 20 activates the electron gun 12 . The electron gun 12 emits an electron beam with a constant intensity when its operation stabilizes after being activated. In this state, the control unit 20 applies current to the scanning coil 13 (the first to fourth coils 131 to 134 of the scanning coil 13) to change the traveling direction of the electron beam passing through the scanning coil 13, thereby causing the electron beam on the sample stage 11 to move. , the electron beam irradiation position on the surface of the sample (at this point, the standard sample) 90 is moved.

Here, the change in the traveling direction of the electron beam in the scanning coil 13 is specifically controlled as follows. When a current is passed through the first coil 131 and the second coil 132, the traveling direction of the electron beam is bent in the Y direction. can be bent into Switching the direction of these currents switches between positive and negative in the X (or Y) direction. The higher the current, the more the electron beam is bent in the X (or Y) direction. By appropriately combining the directions and magnitudes of the currents to be supplied to the first to fourth coils 131 to 4th coils and changing the combination, the direction of travel of the electron beam is changed.

By moving the irradiation position of the electron beam on the standard sample in this way, a characteristic X-ray having a wavelength determined by the type of the predetermined element contained in the standard sample is generated at each irradiation position. Since the predetermined element is uniformly distributed in the standard sample, the intensity of characteristic X-rays emitted from each irradiation position is substantially uniform. The emitted characteristic X-rays are spectroscopically separated by one of the plurality of analyzing crystals 15 having a spectroscopy wavelength that matches the wavelength of the characteristic X-rays. detected by the device 16 (step 2).

The standard sample intensity distribution value acquiring unit 31 acquires from the control unit 20 information indicating the position of the surface of the standard sample irradiated with the electron beam at predetermined time intervals during the movement of the electron beam, and also acquires the value of the detected intensity. is obtained from the X-ray detector 16 . The standard sample intensity distribution value storage unit 32 stores the detected intensity value (standard sample intensity distribution value) for each position on the surface of the standard sample acquired by the standard sample intensity distribution value acquiring unit 31 together with the position information. (Step 3).

Here, the distribution of the detected intensity for each position measured with the standard sample will be described. In the X-ray detector 16, the characteristic X-ray 92 emitted when the electron beam is irradiated to the center of the range (scanning range) in which the irradiation position of the electron beam is moved on the surface of the standard sample passes through the center of the hole of the slit 161. The position of the X-ray detector 16 is set so that it passes (FIG. 5). As the irradiation position of the electron beam moves from the center of the scanning range, the position where the characteristic X-ray 92 passes through the hole of the slit 161 also moves. As the passing position of the characteristic X-ray 92 moves in the width direction of the hole of the slit 161, part of the characteristic X-ray 92 is irradiated outside the hole of the slit 161 and is blocked, resulting in X-ray detection. It no longer reaches the portion 162 (FIG. 6). As a result, the intensity detected by the X-ray detector 16 becomes smaller than the original value.

Therefore, when the intensity detection values for each position on the surface of the standard sample are mapped and displayed, even though the characteristic X-rays are emitted at approximately the same intensity from each position on the standard sample, it appears as if the intensity is appears to have different intensity distributions. For example, as shown in FIG. 7, in one direction (vertical direction in FIG. 7), a certain range 93 from the center, that is, in a range in which all of the characteristic X-rays 92 reaching the position of the slit 161 pass through the hole of the slit 161 , have substantially the same intensity. On the other hand, when moving away from the range 93 in the one direction, the detection intensity decreases. 1, 5, and 6, the slit 161 extends in the direction perpendicular to the paper surface of FIGS. A portion of the light is not blocked outside the hole of the slit 161, and the detection intensity is constant. Therefore, no detected intensity distribution occurs in the horizontal direction of FIG.

As described above, even though characteristic X-rays with almost the same intensity are emitted from each position on the standard sample, as the electron beam irradiation position moves from the center of the scanning range, the detected intensity is originally is smaller than the value of , and an intensity distribution different from the actual one is detected. Such an intensity distribution different from the actual one also occurs when the sample to be measured is analyzed. Therefore, if the obtained intensity values are used as they are for elemental quantitative analysis, accurate data cannot be obtained. Can not. Therefore, in this embodiment, the intensity distribution value of the measurement target sample is corrected using the measurement results of the standard sample obtained up to step 3, as will be described later.

After completing the measurement on the standard sample, the control unit 20 controls the electron gun 12 to stop emitting the electron beam. The user removes the standard sample from the sample stage 11 and places the sample to be measured on the sample stage 11 (step 4). Then, in the same way as when measuring the standard sample, the control unit 20 causes the electron gun 12 to emit an electron beam with a constant intensity, and the scanning coil 13 to change the traveling direction of the electron beam, thereby causing the sample stage 11 to The electron gun 12 and the scanning coil 13 are controlled so as to move the irradiation position of the electron beam on the surface of the sample (here, the sample to be measured) 90 . As a result, the sample to be measured emits characteristic X-rays having wavelengths corresponding to the elements contained therein. The emitted characteristic X-rays are spectroscopically separated by one of the plurality of analyzing crystals 15 having a spectroscopy wavelength that matches the wavelength of the characteristic X-rays. detected by the device 16 (step 5).

The measurement target sample intensity distribution value acquisition unit 33 acquires from the control unit 20 information indicating the position of the surface of the measurement target sample irradiated with the electron beam at predetermined time intervals during the irradiation of the electron beam, and Detected intensity values (intensity distribution values of the sample to be measured) for each position above are obtained from the X-ray detector 16 (step 6). Here, by matching the timing of starting acquisition of the detected intensity value and the time interval with those when measuring the standard sample, measurement at the same position as the position where the detected intensity of the characteristic X-ray from the standard sample was acquired The detected intensity of characteristic X-rays from the target sample can be obtained.

In the measurement of the sample to be measured, for the same reason as in the case of the standard sample, as the electron beam irradiation position moves from the center of the scanning range, part of the characteristic X-rays is blocked outside the hole of the slit 161. Therefore, when the intensity detection values for each position are mapped and displayed, it is detected as if an intensity distribution different from the actual one exists. For example, when there are regions in which a predetermined element exists (first predetermined element presence region 941, second predetermined element presence region 942, third predetermined element presence region 943) within the scanning range of the surface of the sample to be measured, The results of detecting the intensity of characteristic X-rays of a predetermined wavelength emitted from the predetermined element for each position within the scanning range are mapped and displayed as shown in FIG. In this example, the background region 940, which is the region around the first to third predetermined element presence regions 941 to 943, is actually uniform, as in the case of the standard sample, but it looks as if it is shown in the figure. It is displayed as if there is a distribution of strong and weak detection intensities in the vertical direction. On the other hand, the first predetermined element presence region 941 is displayed as if the detection intensity is uniform, and the second predetermined element presence region 942 and the third predetermined element presence region 943 are displayed with different detection intensities in the vertical direction of the figure. It is displayed as if the distribution occurs. However, it cannot be determined that such a distribution of detected intensities actually occurs in the first to third predetermined element existence regions 941 to 943. FIG. Therefore, the post-correction measurement target sample intensity distribution value calculation unit 34 corrects the measurement target sample intensity distribution value as follows.

First, the post-correction measurement target sample intensity distribution value calculation unit 34 obtains the detection intensity obtained from the standard sample for each position (denoted as position (x, y)) within the scanning range from the standard sample intensity distribution value storage unit 32. get the values Ir(x, y) of and find the maximum intensity Ir _max among those Ir(x, y). Then, using this maximum intensity Ir _max , a correction coefficient kr(x, y)=Ir(x, y)/Ir _max of the detected intensity is obtained for each position (x, y) (step 7). If the sample stage 11, the analyzing crystal 15, and the X-ray detector 16 are arranged at the correct positions, the maximum intensity _Irmax is the characteristic X-ray emitted from a certain position on the surface of the standard sample and dispersed by the analyzing crystal 15. The correction coefficient kr(x, y) indicates the detected intensity when all pass through the slit 161, and the correction coefficient kr(x, y) is the characteristic X-ray emitted from each position (x, y) and dispersed by the analyzing crystal 15, passing through the slit 161. It shows the intensity ratio of characteristic X-rays. 7, the correction coefficient kr(x, y) has a maximum value of 1 at the center in the vertical direction of the figure, as shown in FIG. has a decreasing distribution towards

In the measurement of the sample to be measured, the characteristic X-rays pass through the slit 161 at a rate similar to that of the standard sample. Assuming that the intensity of the characteristic X-ray is Ist(x, y), the intensity Is(x, y) detected by the X-ray detector 16 after passing through the slit 161 is Is(x, y)=Ist(x, y )×kr(x, y). Therefore, Ist(x, y) is obtained by Ist(x, y)=Is(x, y)/kr(x, y). The distribution of elements in the sample to be measured is the intensity of Ist(x, y) where the influence of the slit 161 is eliminated, rather than Is(x, y) affected by part of the characteristic X-rays blocked by the slit 161. corresponds to the distribution.

Therefore, the post-correction measurement target sample intensity distribution value calculation unit 34 converts the detection intensity Is(x, y) for each position (x, y) obtained by the measurement of the measurement target sample into the correction coefficient kr(x , y) to obtain the post-correction measured sample intensity distribution value Ist(x, y) (step 8). By the above operation, the intensity correction operation for one measurement target sample is completed.

When the correction operations in steps 7 and 8 are performed on the mapping of the detection results shown in FIG. 8, as shown in FIG. Corrected to increase the value. As a result, the background region 940 has a substantially uniform intensity. The first predetermined element presence region 941 appears to have a uniform intensity within the region in FIG. , and the distribution of the corresponding elements is also uneven. On the other hand, the second predetermined element presence region 942 and the third predetermined element presence region 943 appear as if there is a distribution of strength and weakness of the detection intensity within the region in FIG. It can be seen that the detected intensity within the region is uniform, and the distribution of the corresponding elements is also uniform. Further, although the inside of the third predetermined element existence region 943 is shown with an intensity weaker than the maximum intensity in FIG. 8, it is actually detected with an intensity close to the maximum intensity as shown in FIG. As described above, it can be seen that the actual detected intensity distribution after correction is different from the apparent detected intensity distribution before correction.

According to the EPMA1 and the EPMA data correction method of the present embodiment, by correcting the intensity value for each position within the scanning range acquired using beam scanning, even if the characteristic X Accurate data can be obtained even if part of the line includes a scan range that does not pass through the slit. Therefore, even when performing measurement in a wider scanning range than in the conventional art, it is not necessary to use time-consuming stage scanning, and only beam scanning can be used, so that measurement time can be shortened.

(3) Modifications The present invention is not limited to the above embodiments, and various modifications are possible. For example, although the scanning coil 13 is used as the electromagnetic field source for moving the electron beam in the above embodiment, an electrode for applying an electric field to the electron beam may be used together with or instead of it.

In the above embodiment, one measurement target sample is measured after the standard sample is measured, and the data obtained from the measurement target sample is corrected. Data obtained from each of the plurality of measurement target samples may be corrected after measurement of the target sample is performed.

After setting the positions of the analyzing crystal 15 and the X-ray detector 16, the standard sample is measured once to obtain the correction coefficient. The correction coefficient may be used for correction without execution. However, even in that case, there is a possibility that the positions of the analyzing crystal 15 and the X-ray detector 16 may shift during long-term use of the EPMA. It is better to find the coefficient.

In the above-described embodiment, by matching the timing of starting acquisition of the detection intensity value and the time interval of acquisition of the detection intensity value during measurement of the standard sample and measurement of the measurement target sample, characteristic X-rays from the standard sample The detected intensity of the characteristic X-ray from the sample to be measured is obtained at the same position as the position where the detected intensity of . However, in the standard sample, the difference in the detected intensity obtained from a certain position and a position slightly deviated from it is not so large, so the acquisition position of the detected intensity of the characteristic X-ray is completely the same for the standard sample and the sample to be measured. There is no problem even if it deviates to some extent.

In addition, it is not essential that the standard sample and the sample to be measured have the same interval between the positions at which the detection intensities are acquired, and the standard sample may be acquired at a coarser interval than the sample to be measured. In that case, the correction of the detected intensity for each position in the sample to be measured may be performed using the value of the detected intensity obtained with the standard sample at the position closest to that position. In this way, when the standard sample is acquired at coarser intervals than the sample to be measured, the electron beam can can be moved faster, thereby shortening the measurement time of the standard sample.

In the examples shown in FIGS. 11 and 12, in the vertical direction of these figures, the detected intensity at each position in the standard sample is measured at intervals coarser than those in the sample to be measured, and based on this, the correction coefficient is also the object to be measured. The detected intensity at each position on the sample is obtained at coarser intervals. 11 and 12 corresponds to the direction in which the slit 161 extends, so there is a high probability that the detected intensity will be the same regardless of the position. have the same value. Therefore, the detected intensity for each position on the standard sample can be obtained only on the line on the standard sample surface corresponding to the direction perpendicular to the slit 161, so that the measurement time can be shortened.

Alternatively, instead of the measured intensity values for each position obtained when measuring the standard sample, the average value of the measured intensity values at a plurality of positions within a predetermined range from each position is used. Correction of intensity values for each position may be performed. As a result, even if the intensity values of the standard sample for each position vary due to some cause such as noise, it is possible to suppress variations in the corrected intensity distribution values of the measurement target sample.

In the above embodiment, the EPMA data correction method according to the present invention is implemented in the data processing unit 30 of the EPMA 1. However, after the data acquired by the EPMA is loaded into a separate personal computer or the like, the personal computer or the like can be used. , the EPMA data correction method according to the present invention may be implemented.

[Aspect]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are specific examples of the aspects noted below.

(Section 1)
The EPMA pertaining to paragraph 1 shall:
a sample stage on which the sample is placed;
an electron beam source for irradiating the sample placed on the sample stage with an electron beam;
an electromagnetic field source for generating one or both of an electric field and a magnetic field for controlling the direction of the electron beam so that the irradiation position of the electron beam moves within a predetermined scanning range;
an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage;
an X-ray detector having a slit for passing characteristic X-rays spectroscopically separated by the analyzing crystal and detecting the characteristic X-rays that have passed through the slit;
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value storage unit for storing standard sample intensity distribution values, which are the intensity of characteristic X-rays detected by a detector and generated at each position within the scanning range of the standard sample;
A characteristic X generated at each position of the sample to be measured placed on the sample stage and detected by the X-ray detector while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a measurement target sample intensity distribution value acquisition unit that acquires a measurement target sample intensity distribution value that is the line intensity;
Corrected measurement target sample intensity obtained by correcting the measurement target sample intensity distribution value acquired by the measurement target sample intensity distribution value acquisition unit using the standard sample intensity distribution value read from the standard sample intensity distribution value storage unit and a post-correction measurement target sample intensity distribution value calculation unit that calculates the distribution value.

(Section 4)
The EPMA data correction method according to paragraph 4 is
a sample stage on which a sample is placed; an electron beam source for irradiating the sample placed on the sample stage with an electron beam; an electromagnetic field source that generates one or both of an electric field and a magnetic field that control the direction of the; an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage; and an X-ray detector for detecting the characteristic X-rays that have passed through the slit, the EPMA comprising:
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value and a post-correction measurement target sample intensity distribution value calculation step of calculating the value.

(Section 5)
The EPMA data correction program according to paragraph 5 is
a sample stage on which a sample is placed; an electron beam source for irradiating the sample placed on the sample stage with an electron beam; an electromagnetic field source that generates one or both of an electric field and a magnetic field that control the direction of the; an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage; A program for correcting data acquired by an EPMA comprising an X-ray detector for detecting the characteristic X-rays that have passed through the slit and the characteristic X-rays passed through the slit,
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value and a post-correction measurement target sample intensity distribution value calculation step of calculating the value.

In the EPMA according to the first term, the EPMA data correction method according to the fourth term, and the EPMA data correction program according to the fifth term, a standard sample in which a predetermined element is uniformly distributed within the scanning range is used. A standard sample intensity value at each position within the scanning range detected by an X-ray detector while moving the irradiation position of the electron beam is used. Since characteristic X-rays with substantially the same intensity are emitted from such a standard sample regardless of the position within the scanning range, the standard sample intensity value for each position is is a value that reflects the rate of detection by the X-ray detector. By correcting the intensity value of the sample to be measured using this standard sample intensity value, even at positions in the sample to be measured where part of the emitted characteristic X-rays do not pass through the slit, the emitted characteristic X-ray The intensity of the line can be determined accurately. Therefore, accurate data can be obtained even if a part of the characteristic X-rays includes a scanning range that does not pass through the slit, so mapping analysis using beam scanning can be performed over a wider range than in the past. .

(Section 2)
The EPMA according to the second term is the EPMA according to the first term, wherein the measurement target sample intensity distribution value acquiring unit corresponds to each of the positions of the standard sample from which the standard sample intensity distribution values are acquired. The measurement target sample intensity distribution value is acquired at each position of the target sample.

According to EPMA according to the second term, the intensity distribution values of the measurement target sample are acquired at each position of the measurement target sample that corresponds one-to-one with each position of the standard sample from which the standard sample intensity distribution value was acquired. Therefore, correction can be performed accurately at each position of the sample to be measured.

(Section 3)
The EPMA pertaining to paragraph 3 is the EPMA pertaining to paragraph 1 that:
The measurement target sample intensity distribution value acquisition unit acquires the measurement target sample intensity distribution values at more positions than the positions of the standard sample at which the standard sample intensity distribution values were acquired,
The post-correction measurement target sample intensity distribution value calculation unit performs post-correction measurement using the standard sample intensity distribution value acquired at the position closest to each position where the measurement target sample intensity distribution value was acquired. A target sample intensity distribution value is calculated.

According to the EPMA according to the third term, the number of positions for acquiring the intensity distribution value of the standard sample is smaller than the position for acquiring the intensity distribution value of the sample to be measured, so the time required for measuring the standard sample can be shortened. .

11... Sample stage 12... Electron gun (electron beam source)
13... Scanning coil (electromagnetic field source)
Reference Signs List 1301 First axis 1302 Second axis 131 First coil 132 Second coil 133 Third coil 134 Fourth coil 14 Objective lens 15 Analysis crystal 16 X-ray detector 161 Slit 162 X Line detection unit 17 Stage driving mechanism 20 Control unit 30 Data processing unit 31 Standard sample intensity distribution value acquisition unit 32 Standard sample intensity distribution value storage unit 33 Measurement target sample intensity distribution value acquisition unit 34 Measurement after correction Target sample intensity distribution value calculator 90 Sample 91 Electron beam 92 Characteristic X-ray 93 Range 940 where all characteristic X-rays that have reached the position of the slit pass through the slit hole 940 Background region 941 First predetermined Element existence region 942 Second predetermined element existence region 943 Third predetermined element existence region

Claims (5)

a sample stage on which the sample is placed;
an electron beam source for irradiating the sample placed on the sample stage with an electron beam;
an electromagnetic field source for generating one or both of an electric field and a magnetic field for controlling the direction of the electron beam so that the irradiation position of the electron beam moves within a predetermined scanning range;
an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage;
an X-ray detector having a slit for passing characteristic X-rays spectroscopically separated by the analyzing crystal and detecting the characteristic X-rays that have passed through the slit;
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value storage unit for storing standard sample intensity distribution values, which are the intensity of characteristic X-rays detected by a detector and generated at each position within the scanning range of the standard sample;
A characteristic X generated at each position of the sample to be measured placed on the sample stage and detected by the X-ray detector while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a measurement target sample intensity distribution value acquisition unit that acquires a measurement target sample intensity distribution value that is the line intensity;
Corrected measurement target sample intensity obtained by correcting the measurement target sample intensity distribution value acquired by the measurement target sample intensity distribution value acquisition unit using the standard sample intensity distribution value read from the standard sample intensity distribution value storage unit An electron beam probe microanalyzer, comprising: a post-correction measurement target sample intensity distribution value calculation unit that calculates a distribution value. The measurement target sample intensity distribution value acquisition unit acquires the measurement target sample intensity distribution value at each position of the measurement target sample corresponding to each of the positions of the standard sample from which the standard sample intensity distribution value was acquired. The electron probe microanalyzer of claim 1. The measurement target sample intensity distribution value acquisition unit acquires the measurement target sample intensity distribution values at more positions than the positions of the standard sample at which the standard sample intensity distribution values were acquired,
The post-correction measurement target sample intensity distribution value calculation unit performs post-correction measurement using the standard sample intensity distribution value acquired at the position closest to each position where the measurement target sample intensity distribution value was acquired. calculating a target sample intensity distribution value;
An electron probe microanalyzer according to claim 1. a sample stage on which a sample is placed; an electron beam source for irradiating the sample placed on the sample stage with an electron beam; an electromagnetic field source that generates one or both of an electric field and a magnetic field that control the direction of the; an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage; and an X-ray detector for detecting the characteristic X-rays that have passed through the slit, the EPMA comprising:
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value A correction method for EPMA data, comprising: a post-correction measurement target sample intensity distribution value calculation step of calculating a value. a sample stage on which a sample is placed; an electron beam source for irradiating the sample placed on the sample stage with an electron beam; an electromagnetic field source that generates one or both of an electric field and a magnetic field that control the direction of the; an analyzing crystal that disperses characteristic X-rays emitted from the sample placed on the sample stage; A program for correcting data acquired by an EPMA comprising an X-ray detector for detecting the characteristic X-rays that have passed through the slit and the characteristic X-rays passed through the slit,
A standard sample in which a predetermined element is uniformly distributed within the scanning range is placed on the sample stage, and the X-ray beam is scanned while moving the irradiation position of the electron beam within the scanning range by the electromagnetic field source. a standard sample intensity distribution value acquiring step of acquiring a standard sample intensity distribution value, which is the intensity of characteristic X-rays generated at each position within the scanning range of the standard sample detected by a detector;
After the sample to be measured is placed on the sample stage, the electromagnetic field source moves the irradiation position of the electron beam within the scanning range, and the X-ray detector detects each of the samples to be measured. a measurement target sample intensity distribution value acquiring step of acquiring a measurement target sample intensity distribution value that is the intensity of the characteristic X-ray generated at the position;
Corrected intensity distribution of the sample to be measured obtained by correcting the intensity distribution value of the sample to be measured acquired in the step of acquiring the intensity distribution value of the sample to be measured using the standard sample intensity distribution value acquired in the step of acquiring the standard sample intensity distribution value An EPMA data correction program for causing a computer to execute a post-correction measurement sample intensity distribution value calculation step of calculating a value.

Images