JPH01115045A - Electron beam microanalizer - Google Patents

Abstract

PURPOSE:To use one species of spectroscopic crystal and to enable the upgrading of quantitative precision by extruding a first component from a characteristic X-ray peak which contains both the first and second components and computing the second component based on the X-ray peak of the second component standard sample. CONSTITUTION:Characteristic X rays from a sample are separated to be detected by the use of single spectroscopic crystal 1. A characteristic X-ray spectrum of a first component in a standard sample, that of a second component in the standard sample, and that of an unknown sample are memorized. The first component is computed from the single characteristic X-ray peak of the first component in the unknown sample and that X-ray peak of the first component in the standard sample. The first component is extruded from the characteristic X-ray peak which contains both the first and second components to compute the characteristic X-ray peak of the second component. The second component is computed on the basis of the characteristic X-ray peak of the second component in the standard sample. Quantitative analysis can be thus made possible with good precision by one spectroscopic crystal part.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electron beam microanalyzer equipped with a function that can automatically perform quantitative analysis of compound samples, particularly for example, titanium nitride (TiNx). The present invention relates to an electron beam microanalyzer that can perform quantitative analysis even when the peak of the characteristic X-ray spectrum of one component overlaps the peak of the other component.

(Prior art) For example, when performing quantitative analysis of titanium nitride, two types of crystals, LiF and Pb5D, are used as spectroscopic crystals. LiF is used to measure the alpha rays of titanium, and Pb5D is used to measure the Measure alpha rays and titanium radiation Qfi. Since the α-ray peak of titanium is a single peak, the amount of titanium is determined from the characteristic X-ray spectrum of the standard sample. On the other hand, since the peaks of the alpha rays of nitrogen overlap with the LQ rays of titanium, we removed the LQ rays of titanium from the overlapping peaks based on the peak of the alpha rays of titanium determined by m. Calculate the peak. The amount of nitrogen is determined from the calculated α-ray peak and the characteristic X-ray spectrum of the standard sample.

(Problem to be solved by the invention) Since the characteristic X-ray wavelengths of α-rays from titanium and LA-rays from titanium have a large difference in wavelength, it is difficult to analyze them with a single spectroscopic crystal.
Two types of spectroscopic crystals must be used.

In addition, the alpha rays of titanium, the Lfl rays of titanium, and the alpha rays of nitrogen
Since the wavelength difference between the characteristic X-rays is large and the behavior of these characteristic X-rays in the sample is considerably different, quantitative accuracy cannot be improved.

An object of the present invention is to provide an electron beam microanalyzer that can improve quantitative accuracy by using one type of spectroscopic crystal and performing quantitative analysis using characteristic X-rays with similar energy. .

(Means for Solving the Problems) The present invention will be explained with reference to FIG.
Detection means 2, 3.4 for detecting radiation, first component storage means 5 for storing the characteristic X-ray spectrum of the standard sample of the first component of the sample, and characteristic X-ray spectrum of the standard sample of the second component of the sample. A second component storage means 6 for storing a spectrum, a means 7 for storing a characteristic X-ray spectrum of an unknown sample, and a first component storage means 6 for storing a characteristic X-ray spectrum of an unknown sample.
storage means 5 for the individual characteristic X-ray peak of the component and the first component;
a first component calculation means 8 for calculating the first component from the same characteristic X-ray peak of the standard sample of the first component stored in the first component; and a characteristic X-ray peak containing both the first component and the second component. a second component calculation means 9 for calculating the second component based on the same characteristic X-ray peak of the standard sample of the second component stored in the second component storage means 6 by removing the first component from the second component; , a correction means 10 for performing quantitative correction when the sample is a bulk sample, and a display means 11 for displaying analysis results.

(Function) Taking quantitative analysis of titanium nitride as an example, it will be explained using FIGS. 2(A) to 2(E) and FIG. 3.

First, a titanium standard sample is irradiated with an electron beam to measure a titanium standard spectrum (A), and this is stored in the first component standard spectrum storage means 5. Similarly, a nitrogen standard sample is irradiated with an electron beam, and its spectrum (B) is stored in the second component standard spectrum storage means 6. Next, the titanium nitride sample to be measured is irradiated with an electron beam, and a spectrum (C) is measured and stored in the unknown sample spectrum storage means 7. For titanium, Lα rays and L12 rays are measured, and for nitrogen, α rays are measured. Titanium LQ
The characteristic X-ray peak wavelengths of the X-rays, nitrogen, and α-rays overlap. Since the LQ line and Lα line of titanium have close energies, they can be detected with a single spectroscopic crystal.

Spectra (A) and (
C), the primary measured value I (Ti) of titanium can be calculated using the following equation (1).

I(Ti)=TiLαu/TiLa5 −(1)Ti
LαU is the peak height of the titanium α-ray unknown sample, Ti
LαS is the peak height of the titanium Lα ray standard sample.

Next, the magnitude of the titanium LQ peak is calculated from the titanium Lα peak in the spectrum of the unknown sample, and it is subtracted from the peak where the titanium Lfi line and the α line overlap with nitrogen.
) Calculate the peak of alpha rays in the nitrogen of the unknown sample. Using the α-ray peak for this nitrogen, the following (2)
The primary measured value of nitrogen I (N) is calculated by the formula.

I(N)=NKau/NKas −・=(2)NK
αU is the peak height of the unknown sample of nitrogen α rays, NKαS
is the peak height of the standard sample of nitrogen alpha rays.

When the sample is a thin film sample, the calculated primary measurement values I (Ti) and I (N) become the concentration. On the other hand, when the sample is bulk, the primary measured values I (Ti), I (N
) is subjected to known ZAF correction. The quantitative value corrected in this way becomes the concentration.

(Example) FIG. 4 shows an example.

Reference numeral 12 denotes a stage movable in the X, Y, and Z directions, and is moved by an X motor 13, a Y motor 14, and a Z motor 15 controlled by a stage control section 16. A sample stage 17 fixed to the stage 12 is provided with an unknown sample 18 to be measured, a standard sample 19 of titanium as a first component, and a standard sample 20 of nitrogen as a second component. 21 is an electron beam, and by moving the stage 12, the electron beam 21 can be irradiated onto either the unknown sample 18 or the standard sample 19 or 20.

Reference numeral 22 denotes a spectrometer, which includes a spectroscopic crystal 1 that spectrally spectra the characteristic X-rays from the sample 18 or standard sample 19, 20 irradiated with the electron beam 21, and a detector 2 that detects the spectroscopic characteristic X-rays.
It is equipped with As the spectroscopic crystal 1, a population accumulation film crystal is used. The detection signal of the detector 2 is amplified by the amplifier 3,
After being counted by the counting circuit 4, it is taken into the CPU 23.

The CPU 23 stores the characteristic X-ray spectrum, and
It has the ability to separate waveforms of overlapping peaks and perform quantitative analysis. First component standard spectrum storage means 5 shown in FIG. Second component standard spectrum storage means 6, unknown sample spectrum storage means 7. The first component calculation means 8, the second component calculation means 9, and the correction means 10 are realized by the CPU 23. The CPU 23 also controls the sample 1 on the sample stage 17.
8. The function of controlling the stage controller 6 in order to select the standard sample 19.20 and move it to the position where it is irradiated with the electron beam 21, and the function of rotating the spectroscopic crystal 1 via the spectrometer controller 24. We are prepared.

11 are display means C and RT.

By using the electron beam microanalyzer of the present invention, it is possible to quantify vanadium oxide, for example, in addition to titanium nitride. In vanadium oxide, the Lβ line of vanadium and the α line peak of oxygen overlap, so vanadium is quantified by the α line peak of vanadium, and then the β line peak of vanadium and the α line peak of oxygen are separated to determine the oxygen concentration. Quantification can be performed.

(Effect of the invention) In the present invention, characteristic X-rays from a sample are spectrally detected using a single spectroscopic crystal, and characteristic X-rays of a standard sample of the first component of the sample are detected.
The line spectrum, the characteristic X-ray spectrum of the standard sample of the second component, and the characteristic X-ray spectrum of the unknown sample are stored, and the single characteristic X-ray peak of the first component of the unknown sample and the characteristic X-ray spectrum of the standard sample of the first component are stored. The first component is calculated from the same characteristic X-ray peak, and the characteristic X-ray peak of the second component is calculated by removing the first component from the characteristic X-ray peak that includes both the first and second components. However, since the second component is calculated based on the same characteristic X-ray peak of the standard sample of the second component, quantitative analysis can be performed with one spectroscopic crystal. Moreover, since characteristic X-ray peaks with energies close to each other are used, the quantitative accuracy is increased.

Furthermore, since only one spectroscopic crystal is required, automation control becomes easy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the present invention, FIGS. 2(A) to 2(E) are waveform diagrams showing an example of the operation, FIG. 3 is a flowchart showing an example of the operation, and FIG. 4 is an embodiment. FIG. 1... Spectroscopic crystal. 2...Detector. 3...Amplifier, 4...Counting circuit. 5... First component standard spectrum storage means, 6.
...Second component standard spectrum storage means, 7...
... unknown sample spectrum storage means, 8 .... first component calculation means, 9 .... second component calculation means, 10 .... correction means. 11...Display means. Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] (1) A single spectroscopic crystal that spectrally spectra characterizes the characteristic X-rays from the sample, a detection means that detects the spectroscopic characteristic X-rays, and a single spectroscopic crystal that stores the characteristic X-ray spectrum of the standard sample of the first component of the sample. a second component storage means for storing a characteristic X-ray spectrum of a standard sample of a second component; a means for storing a characteristic X-ray spectrum of an unknown sample; and a first component of the unknown sample. a first component calculation means for calculating a first component from a single characteristic X-ray peak of and the same characteristic X-ray peak of a standard sample of the first component stored in the first component storage means;
The first component is removed from the characteristic X-ray peak containing both the first component and the second component, and the same characteristic X-ray peak of the standard sample of the second component stored in the storage means for the second component is also extracted. An electron beam microanalyzer comprising: a second component calculation means for calculating a second component; a correction means for performing quantitative correction when the sample is a bulk; and a display means for displaying analysis results.