JPH0736005B2 - Surface layer analysis method - Google Patents

Description

Detailed Description of the Invention a. TECHNICAL FIELD The present invention relates to a method for analyzing a thin layer formed on a sample surface by an X-ray microanalyzer or the like.

B. BACKGROUND ART Since an X-ray microanalyzer is configured to irradiate a sample with an excitation electron beam converged on the sample surface, it has an excellent resolution in the spreading direction of the sample surface and is suitable for local analysis. However, it is several tenths of μ in the depth direction from the sample surface.
In principle, it is impossible to analyze a surface layer with a resolution of several m to several μm and a thickness of several hundred liters such as a discoloration layer or a corrosion layer on the metal surface. Uses X-ray photoelectron spectroscopy or Auger electron spectroscopy. However, the X-ray microanalyzer has an extremely excellent resolution in the direction of the sample surface and a remarkably excellent quantitative property as compared with the X-ray photoelectron spectroscopy analyzer or the Auger electron spectroscopy analyzer.

C. Problems to be Solved by the Invention As described above, the conventional X-ray micro-analysis does not have an analyzer which has a high resolution in the surface direction and an excellent quantitative property for the analysis of an extremely thin layer on the sample surface. There is a demand for the appearance of an analyzer having a performance that combines the resolution and quantification in the plane direction of the analyzer and the surface layer analysis capability of an analyzer such as ESCA.

The present invention responds to this situation, and it is an object of the present invention to provide a method capable of analyzing a surface layer having a thickness of several 10Å to several 1000Å with high resolution in the plane direction and excellent quantitativeness.

D. Means for Solving Problems According to the present invention, a sample surface etching means such as ion etching is attached to the structure of an X-ray microanalyzer, and the surface layer of the surface layer is compared by comparing the analysis data before and after the etching of the sample surface. It is for extracting analysis data.

E. Action The sample on which the surface layer is formed is analyzed with an X-ray microanalyzer. As shown in Fig. 3, the X-ray generation area Dx of the sample surface irradiated with the electron beam is 1 μm from the sample surface.
Since the surface layer m reaches about 1000 Å, the analysis data obtained in this case includes data related to the surface layer and data related to the inside. Next, when the sample surface is etched, the surface layer is removed, and in this state, data of only the substantial part of the sample which does not include information of the surface layer analyzed by the X-ray microanalyzer is obtained. Therefore, subtracting the X-ray measurement value after etching from the X-ray measurement value before etching, the positive peak is the peak of the element that definitely exists in the surface layer, and the zero or negative peak is the actual sample. It is the peak of the element existing in the part.

F. Embodiment FIG. 1 shows an embodiment of the present invention. An objective lens 1 focuses the electron beam 2 on the surface of the sample 3. An ion gun 4 is unique to the present invention. Reference numeral 5 indicates an ion beam emitted from the ion gun. 6 is an X-ray emitted from the sample surface, 7 is a dispersive crystal of an X-ray spectroscope, and 8 is an X-ray.
It is a line detector. The configuration shown in the figure except for the ion gun 4 is exactly the same as a normal X-ray microanalyzer.
Reference numeral 9 is a signal measuring circuit, which is composed of an amplifier, a rate meter, etc., and its output is inputted to the recording and data processing circuit 10,
The result of data processing by the circuit is displayed on the surface device 11.

The analysis operation of the sample surface layer is performed as follows. First, a sample surface whose surface layer has not been removed is analyzed in the same manner as a conventional X-ray microanalyzer, and the output of the signal measuring circuit at that time is stored in the memory of the data processing circuit 10. .

This data is shown in Figure 2A. Then, the ion gun 4 is operated to etch the surface of the sample 3 by ion bombardment to remove the surface layer. After that, the analysis operation is performed again as the X-ray microanalyzer, and the output of the signal measuring circuit 9 at that time is stored again in the memory of the memory and data processing circuit 10. This data is shown in Figure 2B. Next, the storage data processing circuit 10 subtracts the data in FIG. 2B from the data in FIG.
Calculate the data in Figure C. When the results shown in FIG. 2 are obtained, the peaks of a and b in FIG. 2C are positive,
It is a peak of an element that definitely exists in the surface layer. Figure 2C
The peak of c is negative. This peak exists both in the surface layer and in the sample fabric, but the subtraction result is negative because X-ray absorption is due to the surface layer, so X-rays are more likely to occur after the surface layer is removed. The strength is getting higher.
Generally, a peak whose subtraction result is 0 or negative is an element existing in both the surface layer and the sample cloth. The horizontal axis of FIG. 2 is the X-ray wavelength when the electron beam irradiating the sample is fixed and the wavelength scanning is performed by the X-ray spectrometer. The result shows that peaks such as a, b, and c represent elements different from each other. Further, when the X-ray spectroscope is fixed at the position of the characteristic X-ray wavelength of a certain element and the electron beam is swept, the horizontal axis in FIG. 2 is the length along the electron beam sweep line on the sample surface. And represents the distribution state of the specific element in the lengthwise direction.

G. Effect The apparatus of the present invention has the above-mentioned configuration, the essence of the analysis function is an X-ray microanalyzer, and the addition of the etching means results in a difference in the analysis results between the presence and absence of the surface layer and the analysis of the surface layer. Since it obtains analysis data, it has extremely high resolution in the direction of surface spread, and is capable of analyzing surface layers that were not possible with conventional X-ray microanalyzers, such as X-ray microanalyzers and ESCA. It is superior to the conventional surface analyzers in terms of resolution and quantification, as well as having the functions of the surface analyzer.

[Brief description of drawings]

FIG. 1 is a side view of an essential part of an embodiment of the present invention, FIG. 2 is a graph for explaining an analysis operation according to the same embodiment, and FIG. 3 is a view for explaining an X-ray generation region on a sample surface.

Claims (1)

[Claims] 1. A sample surface is etched with accelerating particles using an apparatus equipped with a means for irradiating a sample surface with an electron beam converged and an X-ray spectroscope for separating X-rays emitted from the sample surface. Means for storing the X-ray detection output of the X-ray spectroscope before and after etching the sample surface, and subtracting the X-ray detection data after etching from the X-ray detection data before etching to obtain the positive portion. A method for analyzing a surface layer, which comprises extracting the data for analysis.