JP2002286661A - Oblique emission x-ray analysis method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new oblique X-ray analysis method for adjusting the angle for taking out characteristic X rays regardless of the symmetrical position relationship between the mounting direction of an X-ray detector and the inclination axis of a sample stage, and restraining the variation in observation view when adjusting the take-out angle. SOLUTION: In an oblique emission electron beam probe micro X-ray analysis method, the take-out angle of the characteristic waves (2) is set to an angle or less where the characteristic X rays (2) from the inside of a sample (3) is not detected by the total reflection phenomenon when the characteristic X rays (2) are to be detected by an X-ray detector (5). In the analysis method, the position of the sample (3) on a Z axis is adjusted to set the take-out angle of the characteristic X rays (2) to the angle or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oblique emission X
The present invention relates to a line analysis method. More specifically, the invention of this application relates to a new oblique emission X-ray probe which is useful as an oblique emission electron probe micro X-ray analysis method for analyzing fine particles on the sample surface and minute inclusions observed on the polished surface of the sample. The present invention relates to a line analysis method.

[0002]

2. Description of the Related Art Conventionally, as a technique for analyzing a minute area of a sample, for example, as shown in FIG. 1A, an electron beam (1) is irradiated on a sample (3) and emitted from the irradiated minute area. Probe X-ray analyzer (EPMA) for detecting characteristic X-rays (2) to be detected by an X-ray detector (5)
It has been known.

However, in this conventional EPMA,
For example, when the minute object (4) exists on the surface of the sample (3), the inside of the sample (3) and the minute object (4)
The characteristic X-rays (2) from both of them are detected (in FIG. 1, the generation region of the characteristic X-rays (2) from the inside of the sample (3) is shown in a pear shape), and the minute object (4 ) Alone was difficult to analyze.

[0004] To solve this problem,
New EPMA by oblique emission X-ray measurement (hereinafter, oblique emission E
PMA) has already been proposed.

The oblique emission EPMA utilizes the total reflection phenomenon of X-rays. For example, as shown in FIG. 1B, a characteristic X-ray (2) of electron beam excitation is detected by an X-ray detector ( When the characteristic X-ray (2) from the inside of the sample (3) is not detected due to the total reflection phenomenon when the characteristic X-ray (2) is detected by the method (5), the sample (3) Only the characteristic X-ray (2) from the minute object (4) on the surface can be detected.

More specifically, as shown in FIG. 2, for example, a characteristic X-ray (2) generated from a minute object (4)
Is normally emitted in all directions in a vacuum. In contrast,
The characteristic X-ray (2) generated inside the sample (3) is the surface of the sample (3) if the angle formed by the characteristic X-ray (2) with respect to the interface between the surface of the sample (3) and vacuum is equal to or larger than the critical angle. Is emitted into the vacuum and is reflected at the interface if the angle is less than the critical angle. This is the X-ray total reflection phenomenon. Focusing on this total reflection phenomenon,
The X-ray detector (5), in which the detection range of the characteristic X-ray (2) is limited by the slit (6), is changed to a characteristic X-ray generated inside the sample (3).
By adjusting the angle to be equal to or less than the critical angle of the line (2), only the characteristic X-ray (2) of the minute object (4) can be detected.
Thereby, excellent analysis of fine particles on the sample surface and minute inclusions observed on the polished surface of the sample can be realized.

[0007]

However, even with the oblique emission EPMA having the excellent analytical ability as described above, there remains a problem to be further improved in practical use.

In the oblique emission EPMA, for example, as shown in FIGS. 3A and 3B, the extraction angle of the characteristic X-ray (2) (in FIG. 3, it is indicated as the extraction angle θ with respect to the sample surface). (3) utilizes the inclination of the sample stage (7) (in FIG. 3, the sample (3) is set on the sample stage (7) via an inclined sample stage (8) having an inclined surface. Therefore, the mounting direction of the X-ray detector (5) had to be orthogonal to the tilt axis of the sample stage (7). This cannot be applied to an EPMA or a scanning electron microscope in which both are not orthogonal to each other, such as a scanning electron microscope with an energy dispersive characteristic X-ray analyzer. Furthermore, there is a concern that the observation field of view will move significantly if the sample stage (7) is tilted.

The invention of this application has been made in view of the circumstances described above, and is an improvement over the prior art, which provides a geometrical positional relationship between the mounting direction of the X-ray detector and the tilt axis of the sample stage. It is an object of the present invention to provide a new oblique emission X-ray analysis method that enables the adjustment of the characteristic X-ray extraction angle regardless of the change of the observation field of view during the adjustment of the extraction angle.

[0010]

Means for Solving the Problems According to the invention of the present application, when the characteristic X-ray is detected by an X-ray detector, the characteristic X-ray from inside the sample is detected by the total reflection phenomenon. In the oblique emission electron probe micro X-ray analysis method in which the characteristic X-ray extraction angle is set to an angle not larger than the angle not set, the characteristic X-ray extraction angle is set to the angle or less by adjusting the position of the sample on the Z axis. An oblique emission X-ray analysis method (Claim 1) is provided.

[0011]

FIG. 4 is a view for explaining an oblique emission X-ray analysis method according to the invention of this application. As shown in FIG. 4, in the invention of this application, when the characteristic X-ray (2) is detected by the X-ray detector (5), the position of the sample (3) on the Z axis is adjusted. , Sample X from inside
The extraction angle of the characteristic X-ray (2) is set to be equal to or smaller than the angle at which the line (2) is not detected due to the total reflection phenomenon.

To further explain, FIG. 4 shows the aforementioned FIG.
Similarly to the above, the sample (3) is set on the inclined sample stage (8) on the sample stage (7). In this case, as the position of the sample (3) on the Z axis, that is, the position in the vertical direction is changed, the angle of the analysis point on the sample (3) with respect to the X-ray detector (5) changes, and The characteristic X-ray (2) is gradually shielded by the inclined surface of the sample stage (8) and the slit (6) positioned in front of the X-ray detector (5), so that the characteristic X-ray (2) is gradually extracted. Range is being restricted. Therefore, by adjusting the position of the sample (3) on the Z axis,
The extraction angle of the characteristic X-ray (2) can be set to be equal to or less than the above angle. The position adjustment can be performed with a Z-axis knob (also referred to as a Z movement knob) for adjusting the working distance of the sample stage (7).

When the position of the sample (3) on the Z axis is adjusted as described above, the X-ray detector (5) is arranged differently from the above-described conventional oblique emission EPMA. Specifically, as shown in FIG. 5, in the conventional oblique emission EPMA, the mounting direction of the X-ray detector (5) and the tilt axis of the sample stage (7) are orthogonal to each other in a positional relationship on a plane. (A),
In carrying out the invention of this application, the X-ray detector (5)
The secondary electron detector is located at the position A, and the sample stage (7) is inclined with respect to the secondary electron detector.

The characteristic X-rays (2) are excited not only by electron beams but also by X-rays and charged particles. Therefore, the oblique emission X-ray analysis method of the invention of this application does not limit the detection target to only the characteristic X-ray (2) of electron beam excitation, but the characteristic X-ray (2) excited by another excitation source. ). In any case, it is needless to say that the extraction angle of the characteristic X-ray (2) can be set by adjusting the position of the sample (3) on the Z axis as described above.

[0015]

FIG. 6 shows a characteristic X-ray SiKα from Si and a characteristic X-ray ZnLα from ZnO when an electron beam is irradiated on zinc oxide (ZnO) particles on a silicon (Si) substrate.
FIG. 7 is a diagram illustrating a relationship between each detection intensity [cps] and a displacement amount ΔZ [mm] in a Z direction of a sample stage on which a Si substrate is mounted. However, it is assumed here that the working distance decreases as ΔZ increases.

As is apparent from FIG. 6, the displacement ΔZ
, The intensity of each characteristic X-ray also changes, and by appropriately setting ΔZ, the characteristic X-ray ZnLα
It can be seen that only one can be detected.

FIGS. 7A and 7B show displacement amounts ΔZ = 0 mm and 2.0 mm with respect to the sample, respectively.
7 shows the results of the energy dispersive X-ray analysis when.

As shown in FIGS. 7A and 7B, when the position of the sample is adjusted with a displacement ΔZ = 2.0 mm, only the characteristic X-ray ZnLα from ZnO particles is strongly detected. We can see that we can do it. In each case, Si
The peak intensities of Kα and ZnLα are as shown in the figure.

FIG. 8 is a graph showing the results of a scanning electron microscope equipped with an energy dispersive X-ray analyzer.
It is a secondary electron image of nO particle.

In the invention of this application, by setting the take-out angle by adjusting the position of the sample on the Z-axis, for example, only the characteristic X-rays from the ZnO particles on the Si substrate can be detected as described above. Therefore, it is not necessary to make the mounting direction of the X-ray detector orthogonal to the tilt axis of the sample stage. As is clear from FIG. 8, the ZnO particles can be obtained by a scanning electron microscope equipped with an energy dispersive X-ray analyzer. Can be accurately captured. In addition, Z of the sample stage
Even if the axial height was changed, the movement of the visual field was small, and observation within the same visual field was possible.

Of course, the invention of this application is not limited to the above examples, and various embodiments are possible in detail.

[0022]

As described in detail above, according to the invention of this application, it is possible to adjust the extraction angle of the characteristic X-ray regardless of the mounting direction of the X-ray detector and the geometrical positional relationship between the tilt axis of the sample stage. A new oblique emission X-ray analysis method is provided, which enables the observation and suppresses the fluctuation of the observation field of view when adjusting the extraction angle. As a result, the oblique emission EPMA can be promoted as a more versatile one applicable to all types of scanning electron microscopes with characteristic X-ray analyzers, greatly contributing to material design and analysis. Can be.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are diagrams illustrating a conventional EPMA and a conventional oblique emission EPMA, respectively.

FIG. 2 is a diagram illustrating detection of electron beam excitation characteristic X-rays in a conventional oblique emission EPMA.

FIGS. 3 (a) and 3 (b) each show a conventional oblique emission EPMA.
FIG. 7 is a diagram for explaining a takeout angle setting in FIG.

FIG. 4 is a diagram illustrating an oblique emission X-ray analysis method according to the invention of this application.

FIG. 5 is a diagram for explaining an inclination direction of a sample stage and an arrangement of an X-ray detector in the oblique emission X-ray analysis method of the present invention.

FIG. 6 is a diagram illustrating the relationship between the detected intensity of characteristic X-ray SiKα from Si and the characteristic X-ray ZnLα from ZnO and the amount of displacement ΔZ in the Z direction when the ZnO particles on the Si substrate are irradiated with an electron beam. It is.

FIGS. 7A and 7B are diagrams showing the results of energy dispersive X-ray analysis when the displacement amount ΔZ is 0 mm and 2.0 mm, respectively.

FIG. 8 is a view showing a secondary electron image of ZnO particles on a Si substrate by a scanning electron microscope equipped with an energy dispersive characteristic X-ray analyzer.

[Explanation of symbols]

 Reference Signs List 1 electron beam 2 characteristic X-ray 3 sample 4 minute object 5 X-ray detector 6 slit 7 sample stage 8 tilted sample stage

Claims (1)

[Claims] 1. An oblique emission X-ray for setting a characteristic X-ray extraction angle below an angle at which characteristic X-rays from the inside of a sample are not detected due to its total reflection phenomenon when characteristic X-rays are detected by an X-ray detector. An oblique-emission X-ray analysis method, wherein an extraction angle of characteristic X-rays is set to be equal to or less than the angle by adjusting a position of a sample on a Z-axis.