JP3649926B2 - Qualitative analysis method using surface analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a qualitative analysis method using a surface analysis instrument in which a precise qualitative analysis is performed by narrowing an energy search width after correcting an energy axis shift of spectrum data.
[0002]
[Prior art]
In general, when analyzing the element distribution on the surface of a sample using a surface analyzer such as an electron probe microanalyzer (EPMA), an Auger electron spectrometer (AES), or an X-ray photoelectron spectrometer (ESCA), Transition line, EPMA: Kα line, Kβ line, Lα line, Lβ line, Mα line, Mβ line, etc. AES: KLL line, LMM line, LVV line, MVV line, etc. ESCA: 1s, 2s, 2p, 3s, 3p , 3d, etc. Transition lines are arranged in advance in energy order (may be in wavelength order in the case of EPMA) and the transition line energy table shown in the list is used to specify certain elements and to set markers for these transition lines. An unknown peak is identified by overlaying it on the measured spectrum and checking whether it matches the unknown peak of the spectrum. On the other hand, it is an analysis for detecting a peak in a spectrum, comparing the energy position of the detected peak with the energy of these transition lines, and identifying the contained element in the sample determined from the measured spectrum. Qualitative analysis is being performed.
[0003]
[Problems to be solved by the invention]
By the way, when the transition line marker and the measurement spectrum are superimposed and displayed as described above, and the qualitative analysis of the contained elements is performed, the energy position of the transition line is determined due to poor alignment of the spectroscope used for measurement or chemical bonding of the sample. Depending on the state of the sample and the charged state of the sample, it is often displayed deviated from the peak position of the measured spectrum. Even if the marker of the transition line is displayed, it may not be useful for peak identification. There is a problem that the line marker cannot be reflected in the identification result simply by observing the line marker, and qualitative analysis with high accuracy cannot be performed.
[0004]
The present invention has been made to solve the above-mentioned problems in qualitative analysis using conventional surface analysis equipment, and even when there is a shift in the energy position of the transition line with respect to the peak position of the measured spectrum, It is an object of the present invention to provide a qualitative analysis method using a surface analysis instrument that enables qualitative analysis of accuracy.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a method for qualitative analysis of a sample surface using a surface analysis instrument, wherein the spectrum data obtained from the sample analysis point is broadened in energy search range. The candidate element is temporarily selected based on the energy position of the spectrum peak and the element transition line energy table, and the transition line marker of the candidate element temporarily selected is superimposed and displayed on the spectrum data for attention. Select the most likely candidate element corresponding to the spectrum peak, and move the peak of the spectrum data or the transition line marker of the most likely candidate element by shifting and matching them. And an energy position of the transition line marker matched with the peak of interest. As a reference, the steps of shifting the entire or part spectrum data to fit the energy reference, the energy search width taken sufficiently narrow, and is characterized in that comprising the step of performing a precise qualitative analysis.
[0006]
In this way, first, qualitative analysis is performed with a wide energy search range, candidate elements are selected, then transition line markers of the selected candidate elements are displayed, and the marker positions are indicated as peak positions of the corresponding spectrum. Or by moving the peak position to the marker position along the energy axis, the energy shift of the peak of the corresponding spectrum is eliminated or minimized. Next, by eliminating or minimizing the energy shift and narrowing the energy search width to perform element identification, the number of transition lines to be selected can be reduced and the identification accuracy can be increased. Also, a transition line can be assigned to a minute peak.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments will be described. FIG. 1 is a diagram showing a schematic configuration of an X-ray photoelectron spectrometer (ESCA) to which a qualitative analysis method for contained elements using a surface analysis instrument according to the present invention is applied. In FIG. 1, X-rays 2 generated from an X-ray source 1 are irradiated on the surface of a sample 4 placed on a sample stage 3, and photoelectrons 5 generated at the irradiation point of the X-ray 2 of the sample 4 are hemispheres. The light is dispersed by the type analyzer 6 and detected by the multichannel detector 7. In the multichannel analyzer 8, the detection signals output from the multichannel detector 7 are collected, and various signal processing is performed by the signal processing system 9 to perform qualitative analysis processing. In addition, 10 is a display device, 11 is a transition line energy table, and 12 is a peak shift correction tool.
[0008]
Next, an embodiment of a qualitative analysis method for contained elements according to the present invention performed in a signal processing system of the X-ray photoelectron spectrometer will be described with reference to the flowchart of FIG. First, the peak position of the spectrum data detected by the multichannel detector 7 is detected to obtain the peak energy position. First, the energy search range is widened so as not to be affected by the energy shift of the measured spectrum, the energy table is searched, a rough qualitative analysis is performed, and candidate elements are temporarily selected (step 21).
[0009]
Next, the detected spectrum data is displayed on the display device 10 and the transition table energy table of the tentatively selected candidate elements is called, and the energy position of the transition line is displayed on the spectrum data as shown in FIG. Overlay and display with (transition line marker). In addition to the transition line name and energy value, the energy table also contains data on the relative intensity of the peak due to the transition line. When the vertical line of the transition line marker is displayed according to the relative intensity, a certain peak appears. It is easy to determine whether it is due to a specific element. In other words, when there is no energy shift, the transition line marker position and the peak position are completely coincident with each other, so it is easy to determine the element, but even if there is an energy shift in the spectrum data, the transition line marker position and the peak position are It is not so difficult to estimate what element the target peak is due to the tendency that the deviation of the deviation is in a certain direction. In this way, candidate elements having the highest possibility of being selected are selected (step 22).
[0010]
Next, by shifting the transition line marker position of the most likely element and the peak position on the spectrum data, shifting the transition line marker or spectrum on the energy axis, the amount of energy shift of the spectrum data is eliminated, Reduce its absolute value to a minimum. The operation of this step will be described in detail. First, assuming that the candidate element having the highest possibility is selected as described above, the transition line marker is shifted in order to shift the transition line marker position of the candidate element. In order to match the peak position of the target spectral data, the marker position of the transition line is gradually shifted using the peak shift correction tool 12, and the shift operation of the correction tool 12 is performed at the portion where the peak position and the marker position are the best match. (Step 23). The minimum shift step can be arbitrarily set up to the minimum interval of measurement data (or less if necessary).
[0011]
At the portion where the marker position is determined, the position is instructed and determined by operating the correction tool 12, and as shown in FIG. 4, the energy axis displaying the spectrum data is also shifted in accordance with the shift of the marker position. (Step 24). For example, assuming that the energy position of the transition line is E and the shift amount including the sign is s, the energy E ′ whose energy is calibrated is expressed by the following equation (1).
E ′ = E + s (1)
[0012]
Next, the energy shift amount of the spectrum data is eliminated by such a method, or the energy shift is corrected to the minimum, and then qualitative analysis is performed again. In this case, the identification energy search width is narrowed to the minimum to cover the minimum energy shift amount (step 25). Thereby, the possibility that a plurality of transition lines overlap one peak is reduced, and a more accurate qualitative analysis can be realized. For example, for minute peaks and satellite peaks near the main peak, the peak name is rarely assigned correctly in normal qualitative analysis. By making it as narrow as possible, it becomes possible to realize a qualitative analysis with higher accuracy, and it is possible to specify a transition line even for a minute peak.
[0013]
In the above embodiment, the spectral peak shift is performed over the entire spectrum. However, the present invention is limited to the case where the spectral peak shift is performed over the entire spectrum. Instead, as in the case of chemical shifts, there may be peak shifts for only certain peaks on the spectrum, or linear (or curvilinear) peaks for two or more peaks. Since there may be a case where a shift has occurred, in such a case, a shift correction is performed corresponding to a specific region causing a peak shift.
[0014]
【The invention's effect】
As described above based on the embodiment, according to the present invention, a candidate element is provisionally selected by performing a rough qualitative analysis with a wide energy search range for the measurement spectrum, and the candidate element temporarily selected. The transition line marker is displayed and the most likely candidate element is selected, and either the transition line marker position or the spectrum peak position of the candidate element is shifted to eliminate or minimize the energy shift amount and to perform qualitative analysis again. As a result, it is possible to perform qualitative analysis with high accuracy and to obtain an advantage that a correct transition line can be specified even for a minute peak.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an X-ray photoelectron spectrometer to which a qualitative analysis method for contained elements using a surface analysis instrument according to the present invention is applied.
FIG. 2 is a flowchart for explaining a qualitative analysis method according to the present invention performed by the X-ray photoelectron spectrometer shown in FIG. 1;
FIG. 3 is a diagram showing a mode in which transition line markers of candidate elements are displayed superimposed on a measurement spectrum.
FIG. 4 is a diagram showing an aspect in which the energy shift amount is minimized by shifting any of the peak of the measurement spectrum and the transition line marker of the most likely candidate element.
[Explanation of symbols]
1 X-ray source 2 X-ray 3 Sample stage 4 Sample 5 Photoelectron 6 Hemispherical analyzer 7 Multichannel detector 8 Multichannel analyzer 9 Signal processing system
10 Display device
11 Transition line energy table
12 Peak shift correction tool

Claims (1)

In a method for qualitative analysis of a sample surface using a surface analysis instrument, an energy search range is widened for spectrum data obtained from a sample analysis point, and an energy position of a spectrum peak of the spectrum data and an element transition line energy table A candidate element based on the above and a transition line marker of the candidate element temporarily selected with respect to the spectrum data are displayed in a superimposed manner, and the candidate most likely to correspond to the spectral peak of interest A step of selecting an element, a step of shifting one of the peak of interest in the spectral data and a transition line marker of the most likely candidate element by shifting them, and a transition matching the peak of interest The energy position of the line marker is used as the energy reference, and the energy reference is met. Step a, the energy search width taken sufficiently narrow, qualitative analysis method according to surface analysis apparatus characterized by comprising the step of performing a precise qualitative analysis for sea urchin spectral data whole or shift part.

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