JPH07190965A - X-ray microanalyzer - Google Patents

Abstract

PURPOSE:To reduce the time required by an X-ray microanalyzer for making qualitative analysis and, at the same time, to reduce damages to samples by a beam. CONSTITUTION:In an X-ray microanalyzer equipped with a spreading type X-ray spectroscope, a storing means 2 which sets in advance references for judging the existing levels of elements to be measured from the combination of presence/absence of detected peak values corresponding to characteristic X rays and stores the references. At the time of measurement, the microanalyzer detects peak values from X-ray measurement values in real time and, at the same time, judges 3 the existing levels of the elements to be measured by comparing the detected peak values with the information stored in the storing means 2 and displays 4 the judgment results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray microanalyzer equipped with a wavelength dispersive X-ray spectrometer.

[0002]

2. Description of the Related Art An X-ray microanalyzer qualitatively or quantitatively analyzes an element present on the surface of a sample by irradiating the surface of the sample with a focused electron beam and detecting characteristic X-rays generated from the surface of the sample. Is a device for performing. In such an X-ray microanalyzer, when the characteristic X-ray is detected, the characteristic X-ray generated from the sample is dispersed by a dispersive crystal,
There is an X-ray microanalyzer equipped with a wavelength dispersive X-ray spectroscope that detects only the separated X-rays with a detector.

By the way, there are many types of the above-mentioned dispersive crystal, and the wavelength range of the characteristic X-ray that can be dispersed is determined. Therefore, normally, when performing qualitative analysis of elements existing on the surface of a sample using this wavelength dispersive X-ray spectrometer, the entire spectral range suitable for determining the presence of the element to be measured is determined. Prepare several kinds of suitable dispersive crystals so that they can be covered. Then, each of the dispersive crystal, the sample, and the X-ray detector always maintains a specific positional relationship (that is, the distance between the dissociated sample and the dispersive crystal and the dispersive crystal and the X-ray detector are always maintained). Under a certain condition (such that the distance between them is equal and the three are on the Rowland circle), the electron beam is irradiated onto a predetermined sample surface, and the spectral wavelength is continuously scanned by the above-mentioned dispersive crystal. Then, the data from the X-ray detector is acquired. When the detection data of all the dispersive crystals are finally prepared, the detection data is comprehensively analyzed to determine whether or not the element to be measured exists.

For example, when copper is present on the surface of the sample, characteristic X-rays having a wavelength of 1.3357 nm are generated as Lα rays of copper. Therefore, an appropriate dispersive crystal is selected and mounted at the time of measurement, and scanning is performed. Then, this characteristic X-ray is detected. The X-ray spectrum obtained as a result naturally has a peak at the wavelength 1.3357 nm. By using such a property, for example, as a result of measurement on an unknown sample, the wavelength of 1.3357
If an X-ray spectrum having a peak at the position of nm is obtained, it can be used as a criterion for judging that copper may be present on the surface of the sample.

However, in making such a determination, it is considered that the peak value of the characteristic X-ray of a certain element may exist close to or overlap with the peak value of the characteristic X-ray of another element. However, even if a peak is detected at a wavelength position of a certain characteristic X-ray, it is problematic in terms of analytical accuracy to determine that the element to be measured is present immediately from this. Therefore, conventionally, several types of dispersive crystals were used, and after measuring over the entire range, a plurality of characteristic X values such as K line, L line, and M line were measured.
The final decision was made comprehensively based on the presence or absence of peak values on the line.

[0006]

However, in such a conventional X-ray microanalyzer, in order to scan a large number of dispersive crystals over the entire range, especially when there are plural kinds of elements to be measured. It took a lot of time, and the judgment result could not be known until all the measurements were completed, and a lot of time was required for the qualitative analysis. Further, since the sample is irradiated with the electron beam for a long time, the beam damage is large depending on the sample.

The present invention is intended to solve the above-mentioned problems and shortens the time required for qualitative analysis by determining and displaying the level of the presence of an element to be measured in real time during X-ray detection. The purpose is to be able to.

[0008]

SUMMARY OF THE INVENTION The present invention is a wavelength dispersion type X
In an X-ray microanalyzer equipped with a line spectroscope, a storage unit for presetting and storing a reference for determining the existence level of an element to be measured by a combination of presence or absence of a detected peak value corresponding to a characteristic X-ray. Determining means for determining the existence level of the element to be measured by detecting the detected peak value of the X-ray measurement value in real time at the time of measurement and comparing the detected peak value with the stored information of the storage means, And display means for displaying the output of the determination means in real time.

[0009]

In the conventional X-ray microanalyzer, only the final judgment is made after all the measurements are completed. For example, in the case of the above-mentioned detection of copper, the characteristic X of wavelength 1.3357 nm is measured. If a line is detected, it can be considered that copper is present to some extent, although it is not sufficient to assert that copper is present. That is, if any characteristic X-ray peak is detected during the measurement, the level of possibility that the element to be measured is present is determined according to the type of the characteristic X-ray at that time. It is possible.

Based on such an idea, according to the X-ray microanalyzer of the present invention, at the time of measurement, each time the X-ray detection peak value appears in the measuring means, the peak value is judged in real time by the storage means. The result is displayed after the level of existence of the element to be measured is determined. Therefore, when the element to be measured exists, the presence level can be known in real time at the time of measurement without ending the scan for the entire range to be measured. Also, when the measurer determines that further measurement is unnecessary, such as when the existence of the element to be measured is confirmed by it,
The measurement can be finished immediately, and the time required for the qualitative analysis can be shortened. Furthermore, with it,
Beam damage of the sample can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a wavelength dispersive X-ray spectroscope, in which a sample 11, a dispersive crystal 12, and an X-ray detector 13 are
It is arranged along the Roland circle 14. At the time of measurement, the sample 11 is irradiated with an electron beam 15, the characteristic X-rays 16 generated from the surface of the sample 11 are dispersed by the dispersive crystal 12, and detected by the X-ray detector 13. To do. At that time, by the control means 17, the dispersive crystal 12
The X-ray detector 13 and the X-ray detector 13 are moved along the Rowland circle 14 while maintaining a predetermined positional relationship, and scanning is performed.

Then, the output of the X-ray detector 13 is measured by the measuring means 18, and as a result, an X-ray spectrum as shown in FIG. 2 is obtained. In the X-ray spectrum of FIG. 2, the horizontal axis represents the X-ray wavelength and the vertical axis represents the measured X-ray value.

The X-ray microanalyzer of this embodiment further comprises a storage means 2, a determination means 3 and a display means 4.

First, the storage means 2 sets in advance a criterion for determining the level of whether or not the element to be measured is present, depending on how to combine the presence or absence of the detected peak value corresponding to the characteristic X-ray. It is something to remember.

Here, the basic idea of the judgment criteria by the storage means 2 will be explained using the example cited above. As described above, as a result of measurement on a certain sample, the wavelength was 1.3357 nm. If an X-ray spectrum having a peak is obtained, it can be judged from the analysis that this corresponds to the Lα line of copper, but it is possible that copper is present on the surface of the sample, but this is deterministic. It's not something. In this case, if the peak value is obtained at the position of the wavelength 0.1542 nm in the X-ray spectrum from the same sample, that is, the position corresponding to the Kα line of copper, the peak value is detected only at the position of the Lα line. It is possible to judge that copper is present on the surface of the sample with a higher possibility than when it was processed. That is, the level indicating whether or not the element to be measured is present in the sample, in other words, the index indicating the degree of possibility that the element to be measured is present in the sample is, for example, the peak corresponding to the L line of the characteristic X-rays. It can be considered that the case where the peak value corresponding to the K line in addition to the L line is detected is higher than the case where only the value is detected.

By the way, various dispersive crystals each have a spectroscopic range (spectral range). This state is shown in FIG. In FIG. 3, for example, PE is used as a dispersive crystal.
If T is used for measurement, K from element Si to Fe
It is shown that α rays, Lα rays from the elements Rb to Dy, and Mα rays from the elements Hf to U can be detected.
As shown in FIG. 3, if various dispersive crystals are used in an appropriate combination, X-ray spectroscopy can be performed on all elements, but at present, only elements that can detect only K rays, or L rays, M There are elements that can only detect lines.

Further, usually, for the element to be measured, the dispersive crystal is selected so that the spectral ranges do not overlap as much as possible. FIG. 4 shows an example of selection of such a dispersive crystal. Therefore, for all the elements to be measured, the existence level judgment criteria are, for example, if only the M line is detected, the existence level is "C" (the possibility of existence is not zero, but the level is low), M Line and L
If a line is detected, the presence level is “B” (C <B), and if three lines M, L, and K are detected, the presence level is the highest “A” (C <B <A). It is difficult to make a uniform decision.

In consideration of the above situation, in the storage means 2 of the present embodiment, the judgment standard of the existence level of the element to be measured is set and stored by the following procedure.

First, the measurer determines the element (1
Or multiple). If not specified, all elements are measured.

Next, the measurer determines which element of the characteristic X-ray is to be measured by which dispersive crystal based on the spectral range table as shown in FIG.

Then, taking this spectral range into consideration, the measurer sets the existence level judgment criterion for each element to be measured. This criterion is a kind of rule defined by a combination of presence / absence of a detected peak value corresponding to the characteristic X-ray.

An example of this setting is shown in FIG. The example shown in FIG. 5 is an example in which B, S, and Au are designated as the elements to be measured, but Kα rays for B, Kα, Kβ rays, and Lα, Lβ for S depending on the combination of the dispersive crystals.
For Au, the lines will be described on the assumption that the Lα and Lβ lines and the Mα and Mβ lines are measurement targets, that is, the measurement is possible.

In this case, B is set so that the presence level is judged to be "A" rank if only the Kα ray is measured. Regarding S, if Kα and Lα rays are measured, it is ranked “A”, and if either Kα ray or Lα ray is measured, it is ranked “B”, either Kβ ray or Lβ ray. If is measured, it is set to rank "C". Furthermore, for Au, Lα
Line and Mα line are measured, it is ranked “A”, and if either Lα line or Mα line is measured, it is “B”
The rank is set to be the “C” rank when either the Lβ ray or the Mβ ray is measured.

Note that FIG. 5 is merely an example, and the criteria for the determination can be freely set based on the measurement purpose of the measurer or the tester's own knowledge. .

Next, the judging means 3 in this embodiment will be described. This judging means 3 monitors the measurement value of the measuring means 18 in real time, and whenever a peak appears in the measurement value, the wavelength of the X-ray detection value at which the peak appears is stored in the storage information of the storage means 2. And the existence level of the element to be measured is determined. In this case, performing these operations in real time is an essential requirement for the present invention.

Explaining the example shown in FIG. 5, the current state of the “presence or absence of detection” in FIG.
Each time the judging means 3 detects the X-ray peak value, it collates with the stored information in the storing means 2 in real time.
It was revealed that the Mβ ray of S was detected, the Lβ ray of S was not detected, and the Lα ray of S, the Lα ray of Au, the Lβ ray, M
The alpha ray shows the situation that it has not been detected so far. As described above, since the determination unit 3 performs the determination operation based on the determination standard stored in the storage unit 2 in real time, the state of the item “general determination” at that time exists for B. The levels “A” and S are the existence level “B”, and the Au are the existence level “C”. However, as a result of continuing the measurement, when the detection peak value corresponding to the Lα ray or Mα ray of Au was detected at a certain point, at that moment, the item of the comprehensive judgment of Au was the existence level “B”. Changed to Lα ray and M
When both α rays are detected, the item of comprehensive judgment is also changed to “A”.

In this way, even if all the measurements are not completed, the information obtained up to that point and the determination criteria stored in the storage means 2 are obtained by the determination means 3 during the measurement. Is performed every moment, and the latest comprehensive judgment at that time is output in real time. In this example, for example, if the measurer determines that the purpose of the measurement is achieved when the presence level of S is found to be "A", the measurement can be interrupted at that time,
It can be easily understood that the time required for measurement can be saved.

The background of the X-ray spectrum obtained as the output of the measuring means 18 contains statistical fluctuations as shown in FIG. Therefore, the determination means 3
From the viewpoint of increasing the accuracy of the existence of peaks due to the above, for example, it is advisable to make settings such as determining only peaks in which the average value of the background is increased by three times or more the intensity of statistical fluctuations as peaks. .

Next, the display means 4 in this embodiment will be described. The display device 4 is, for example, a graphics device or a display device, and displays the output of the determination means 3 in real time. As a display method, for example, the table as shown in FIG. 5 is displayed before the measurement, and after the measurement is started, the “presence / absence of detection” and the “total judgment” items are rewritten and displayed in real time. However, from the viewpoint of ease of recognition by the measurer, color display may be performed in some form.

An example of such color display will be described with reference to FIG. FIG. 6A is an element table which is the basis of the display. When all elements or a large number of elements are to be measured, the table may be left as it is, but when only a few elements are to be measured, It suffices to display a table consisting only of the element names to be measured. Then, after the measurement is started, "A" to "C" are displayed as the result of the comprehensive judgment.
The color within the frame of the element to be measured whose presence level is determined is changed in real time.

An example of changing the color is shown in FIG. 6B. In this example, the frame of the element to be measured is uncolored before the measurement, is kept as it is until a certain existence level is determined, and is colored and displayed in a certain color at the moment of the determination. If the shade of this color is set so as to become darker from the presence level “C” to “A”, the presence level of the element to be measured can be quickly known by the presence or absence of coloring and the shade. Of course, change the color for each level, such as "blue" for the existence level "C", "yellow" for the existence level "B", and "red" for the existence level A. It is also possible to display it.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in an X-ray microanalyzer equipped with an energy dispersive spectroscope, the output of the energy dispersive spectroscope can also be used to determine the existing level of the element to be measured. That is, by combining the detection result at the output of the energy dispersive spectrometer with the conditions of the judgment standard, the judgment can be performed in a shorter time and the measurement time can be saved. Further, if the measurement time can be saved, it is possible to devote it to the peak judgment of minute elements, and the analysis accuracy can be improved.

Further, although the judgment criteria in the storage means 2 have been described as being set by the measurer in the above-mentioned embodiment, the judgment criteria considered in advance may be patterned according to the combination of the element to be measured and the dispersive crystal. For example, it may be possible to appropriately select from among them.

[0034]

As is apparent from the above description, according to the present invention, every time an X-ray detection peak value appears in the measuring means, it is collated with the determination standard of the storing means in real time during measurement. The level of existence of the target element is determined, and the result is displayed. Therefore, when the element to be measured exists, the existence level of the element can be known in real time without ending the scan for the entire range to be measured. In addition, when the operator determines that further measurement is unnecessary, such as when the existence of the element to be measured is confirmed,
The measurement can be finished immediately, and the time required for the qualitative analysis can be shortened. Furthermore, with it,
Beam damage of the sample can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining an X-ray spectrum.

FIG. 3 is a diagram for explaining a dispersive crystal and its spectral range.

FIG. 4 is a diagram showing an example of a combination of dispersive crystals.

FIG. 5 is a diagram for explaining setting of determination criteria according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining the display method of the display means in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wavelength dispersive X-ray spectroscope, 2 ... Storage means, 3 ... Judgment means, 4 ... Display means, 11 ... Sample, 12 ... Spectroscopic crystal, 13
... X-ray detector, 14 ... Roland circle, 15 ... Electron beam, 16 ... Characteristic X-ray, 17 ... Control means, 18 ... Measuring means.

Claims (2)

[Claims] 1. An X-ray microanalyzer equipped with a wavelength dispersive X-ray spectroscope, wherein a combination of presence or absence of a detection peak value corresponding to a characteristic X-ray is used as a criterion for determining the existence level of an element to be measured. A storage means that is preset and stored by one of the elements, an element to be measured by detecting the detected peak value of the X-ray measurement value in real time during measurement and comparing the detected peak value with the stored information of the storage means. An X-ray microanalyzer, comprising: a determination means for determining the existence level of the presence determination means and a display means for displaying the output of the determination means in real time. 2. The display means displays the name of the element to be measured and also displays the presence level of the element to be measured in a color predetermined according to the presence level of the element. X according to claim 1,
Line microanalyzer.