JPH0120680Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus, such as an X-ray microanalyzer, which detects characteristic X-rays generated from a sample by electron beam irradiation with a semiconductor detector and analyzes the sample.

X-ray microanalyzers include a dispersion type analyzer that analyzes characteristic X-rays from a sample by dispersing them into each wavelength using a spectroscopic crystal, as well as a device that directly detects characteristic X-rays from a sample without using a spectroscopic crystal. In some cases, a non-dispersive analyzer is incorporated, which detects the energy with a device and electrically analyzes each energy.

Therefore, when analyzing a sample using such a non-dispersive analyzer, in order to effectively guide the characteristic X-rays generated from the electron beam irradiated part of the sample to the semiconductor detector, a path that is usually longer than the hole diameter is required. A collimator is used. The hole diameter of the collimator needs to be as small as possible in order to reduce false signals due to scattered X-rays.

However, in X-ray analysis of a sample, in addition to point analysis in which the electron beam is fixed at a specific point on the sample, there is also line analysis in which the electron beam is scanned in a line across the sample, and Area analysis is performed by scanning a wide area on the surface. When performing this line analysis or area analysis, a collimator with a small hole diameter will cut out X-rays from a position far from the center of the sample, so in the past, it was unavoidable to use a single collimator with a large hole diameter (for example, about 5 mm). A meter is used to ensure sufficient detection strength during area analysis or line analysis, but scattered X-rays enter the semiconductor detector, making it impossible to improve analysis accuracy.

The present invention aims to solve such drawbacks, and will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention, and 1 is a sample chamber of an X-ray micronizer. A sample stage 3 for horizontally moving the sample 2 is installed inside the sample chamber, and a final stage focusing lens 4 is provided at the top for focusing and irradiating the electron beam EB onto the sample 2. It has been placed. or,
Although not shown, an electron beam deflector is installed and the electron beam
The EB can be scanned along a desired line or within a desired plane.

5 is a semiconductor detector such as lithium-diffused silicon for detecting characteristic X-rays X generated by irradiating the sample 2 with an electron beam EB;
The detector is held at the tip of a detector holder 6 fixed to the side wall of the sample chamber 1. The detector holder 6 is made of a good thermal conductor such as copper, and the other end is integrally fixed to a cooling tank 7 filled with liquid nitrogen or the like. Therefore, the semiconductor detector 5 is constantly cooled. The semiconductor detector 5, the detection holder 6, and the cooling tank 7 are surrounded by a shielding tube 8 and are heat shielded.

9 is the characteristic X from sample 2 after cutting out the scattered X-rays.
a collimator placed in front of the semiconductor detector 5 to make the beam incident on the semiconductor detector 5;
The collimator is formed in a cylindrical shape and is rotatably held on the side wall of the sample chamber 1. As shown in FIG. 2, the collimator 9 has three X-ray passing holes 10a, 10b, and 10 having different hole diameters, for example, the diameters of the X-ray incident surface are 0.7 mm, 2 mm, and 3 mm, respectively.
c are formed, and the centers of the respective holes are placed at equal intervals on a concentric circle with the rotation center 0 of the collimator 10. The X-ray passing hole naturally has a long path compared to the hole diameter, and the diameter of the X-ray exit surface is determined by the size of the semiconductor detector 5, and is formed approximately the same in all holes. There is. Therefore, the passage hole 10a
As can be seen from the figure, the diameter of the entrance surface is smaller than the hole diameter of the X-ray exit surface, and the diameter of the X-ray exit surface is tapered.
0b and 10c, on the other hand, are tapered so that the diameter of the incident surface is larger.

Reference numeral 11 denotes a cylindrical body concentrically fixed to the collimator 9, and a gear 12 is formed on the outer periphery of the cylindrical body. A drive gear 14 fixed to a shaft 13 rotatably held on the side wall of the sample chamber 1 meshes with the gear 12 . The other end of the shaft 13 is taken out into the atmosphere, and a knob 15 is provided. Therefore, when the knob 15 is rotated, the shaft 13, the drive gear 14 and the gear 1 are rotated.
Since the cylinder 11 rotates through the holes 2 and the collimator 9 rotates, each hole 10a, 10
b and 10c can be made to face the semiconductor detector 5 in sequence.

First, as shown in FIG. 1, when the hole 10a of the collimator 9 with the smallest diameter is selected,
0a captures only the electron beam irradiation point on sample 2. Therefore, only the characteristic X-rays
Background scattered X-rays generated inside the sample chamber 1 are blocked by the collimator 9 and do not enter the semiconductor detector 5. Therefore, highly accurate X-ray analysis (point analysis) can be performed.

Next, when performing area analysis (X-ray image display) or line analysis by scanning the electron beam over the sample, turn knob 1.
5, the collimator 9 is rotated, and the hole 10b or 10c is selected depending on the magnification of scanning image observation and set at a position in front of the semiconductor detector 5. By using such holes 10b or 10c, as can be seen from FIG.
For example, the characteristic X-rays generated from 2a and 2b can be effectively made incident on the semiconductor detector 5, and X-ray analysis of a wide area on the sample can be performed.
At this time, due to the large diameter of the holes 10b and 10c of the collimator 9, some scattered X-rays will enter the semiconductor detector 5, but at this time, the minimum diameter of the collimator 9 mentioned earlier If analyzed in advance using the hole 10a, it is possible to mask all but the desired characteristic X-rays using the analyzer of the non-dispersive analyzer, making it possible to perform surface analysis and line analysis with high precision. The value is extremely great.

In the above description, three collimator holes were provided, but the number is not limited to this, and two or four or more holes may be formed.

Also, although it was stated that multiple X-ray passage holes should be replaced by rotating the collimator,
The collimator may be moved linearly.

Furthermore, the present invention is not limited to an X-ray microanalyzer, but can be similarly applied to a scanning electron microscope, a transmission electron microscope, etc.

As explained above, in the present invention, we prepare collimators with different hole diameters on the X-ray entrance surface, and one with a smaller diameter on the entrance surface and one with a larger diameter than the diameter on the exit surface, and perform point analysis. , X-ray passing holes are selected and arranged according to ray analysis and area analysis, and the area of the sample that the semiconductor detector sees can be changed according to the size of the sample analysis, making it possible to analyze a wide area. It is possible to improve analysis accuracy by minimizing the incidence of scattered X-rays on the detector when analyzing a narrow area.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a view of the collimator used in the present invention as seen from the sample side, and FIG. 3 is a diagram illustrating the usage situation of the present invention. 1: sample chamber, 2: sample, 3: sample stage,
4: Focusing lens, 5: Semiconductor detector, 6: Detector holder, 7: Cooling tank, 8: Shield tube, 9: Collimator, 10a, 10b and 10c: X-ray passing hole,
11: cylinder body, 12: gear, 13: shaft, 14: drive gear, 15: knob.

Claims (1)

[Scope of utility model registration request] Means for irradiating an electron beam to enable point analysis, line analysis, or area analysis of a sample surface, and non-dispersive analysis for detecting and spectroscopy of X-rays generated from the sample by irradiation with the electron beam. Equipped with means, non-distributed
The radiation analysis means has a semiconductor detector disposed opposite to the sample surface, and an apparatus including a collimator having an X-ray passage hole with a long path relative to the hole diameter between the semiconductor detector and the sample. , the collimator has different diameters on the X-ray incident plane and
It is equipped with multiple X-ray passing holes, including a tapered hole whose entrance surface diameter is smaller than the diameter of the exit surface, and a tapered hole whose entrance surface diameter is larger than the diameter of the exit surface. An X-ray analysis apparatus comprising means for selectively arranging any one of the X-ray passing holes at a position facing a semiconductor detector according to the X-ray passing hole.