JP2728627B2 - Wavelength dispersive X-ray spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength-dispersive X-ray which irradiates a sample with radiation such as an X-ray or a charged particle beam and analyzes the bonding state of elements and atoms in the sample from X-rays generated from the sample. The present invention relates to an X-ray spectrometer.

[0002]

2. Description of the Related Art In general, in a wavelength-dispersive X-ray spectrometer, a curved dispersive crystal 51 (spectroscope) as shown in FIG. (For example, “Electron beam microanalysis” by Hiroyoshi Fukushima, Nikkan Kogyo Shimbun, p. 63). When a crystal lattice is used as a spectroscope, the wavelength λ of the X-ray to be split is given by 2d · sin θ = n · λ (1). Here, d is an interval between crystal lattices, and θ is an incident angle of the X-rays from the sample 53 to the spectral crystal 51. n is an integer (n = 1, 2,...), but is often used with n = 1, which is the strongest intensity of X-rays to be dispersed. The separated X-rays are reflected from the crystal 51 at an emission angle θ in the direction of the X-ray detector 52. As shown in FIG. 6 (a), analyzing crystal 51, placing the light emitting point 53 _a and the X-ray detector 52 of the X-ray on the sample 53 on the same circumference, X-rays generated from the sample 53, the spectroscopic The light enters the crystal 51 at any position on the surface thereof at the same angle, and is further condensed at the position of the X-ray detector 52, so that the efficiency and the resolution of the apparatus are maximized. This circumference is generally called a Roland circle.

When the position of the sample 53 is shifted from the Roland circumference as shown in FIG. 1B, the X-rays generated from the sample 53 are incident at different angles depending on the location on the surface of the spectral crystal 51. , Wavelengths clearly different from the above equation (1) are separated. Therefore, the wavelength resolution decreases. At the same time, the light-collecting ability also decreases. This means that the wavelength dispersion type X
This means that the depth of focus of the X-ray optical system of the X-ray spectrometer is shallow. This depth of focus is several tens of microns in the case of elemental analysis.
m, several μm in case of state analysis. Therefore, conventionally,
For example, the above-mentioned “electron beam micro-analysis” (P.5)
As disclosed in 1) and Japanese Patent Publication No. 57-55184, there has been proposed an apparatus in which an optical microscope is provided so that the focus can be adjusted by observing the sample surface. That is, as shown in FIG. 5, the focal position of the optical microscope and the focal position of the X-ray optical system are adjusted in advance. Therefore, by adjusting the sample and moving it to the focal position while observing the sample surface with this optical microscope, the sample is set in the focal depth region of the spectral crystal (not shown), and the sample is correctly set. Will be analyzed. Although the above description has been made solely of the case of a crystal X-ray spectrometer, the invention is also generally applicable to a diffraction type X-ray spectrometer such as an artificial multilayer film and a diffraction grating.

[0004]

However, in order to install such an optical microscope, it is necessary to secure a relatively large area (solid angle). In particular, in an X-ray spectroscope of an ion beam excitation type or the like, In order to perform a multifaceted analysis of a sample, a recoil ion analyzer, a secondary electron detector, an energy dispersive X-ray detector, etc. must be installed in addition to the wavelength dispersive X-ray spectrometer. At present, there is no room for installing such an optical microscope. In view of the above, the present invention has been made in view of the above circumstances, and has been made compact or capable of adjusting the position of a sample to a focal position of an X-ray optical system with a relatively simple configuration. It is an object of the present invention to provide a wavelength-dispersive X-ray spectrometer capable of installing other detection devices and the like by saving space.

[0005]

The main means adopted by the present invention to achieve the above-mentioned object is that the main point is that the sample is adjusted to a focal position of the X-ray optical system by a position adjusting mechanism. In a wavelength-dispersive X-ray spectrometer, which irradiates radiation from a radiation source and separates X-rays from the sample with a diffraction-type spectroscope, and then detects the X-rays with an X-ray detector, the optical path at the focal position is A first and a second light beam irradiating means for irradiating light beams from different directions so as to intersect with each other, and driving the position adjusting mechanism so that the sample is located at a position where the optical path intersects. Distributed X
It is a line spectrometer. The light ray in the above configuration is a concept that includes not only visible light such as laser light, but also near ultraviolet rays, near infrared rays, and radiation such as ion beams and X-rays.

[0006]

In the X-ray spectroscopy apparatus according to the present invention, the optical paths of the light beams emitted from the first and second light beam irradiation means are preset so as to intersect at the focal position of the X-ray optical system. By operating the position adjusting mechanism so that the sample is located at the position where the optical paths intersect, the sample can be easily positioned with respect to the focal position of the X-ray optical system.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. The following embodiment is an example embodying the present invention and is not intended to limit the technical scope of the present invention. Here, FIG. 1 is a schematic configuration diagram of an X-ray spectrometer according to one embodiment of the present invention, FIG. 2 is a graph showing the results of analysis of zinc silicate by the X-ray spectrometer, and FIG. It is a schematic structure figure of the X-ray spectroscopy device concerning the example of. First, an example in which the present invention is applied to an ion beam excitation type X-ray spectrometer is shown in FIG.
Shown in Ie, X-ray spectrometer A according to the present embodiment, irradiating an ion beam 1 _a from the radiation source 1 toward the sample 11 pre-positioned at the focal position of the X-ray optical system as will be described later, the sample 11 X-rays generated from the light are separated by the spectral crystal 3, and only the X-rays of the target wavelength are detected by the proportional counter 6.
(X-ray detector) for detection. Incidentally, the ion beam 1 _a is because they do not transmit the air, the sample 11 is placed in a vacuum, the load lock mechanism 12 for the desorption of the sample 11 is provided.
Then, the sample 1 is passed through the load lock mechanism 12.
1 is mounted on a goniometer head 13 in a vacuum.
The sample 11 supported by the goniometer head 13 is adjusted in position by a goniometer 14 (position adjustment mechanism), and is positioned at the above-described focal position.

In this case, in the apparatus of the present embodiment, the first laser light source 2 (first light beam irradiating means) and the second laser light source irradiating, for example, a laser beam from different directions so that the optical paths intersect at the focal position. A laser light source 4 (second light beam irradiating means) is provided. Therefore, only by driving the goniometer 14 to a position where the light beams intersect and adjusting the position of the sample 11 so that the sample 11 is positioned, the sample 11 It can be easily positioned at the focal position of the X-ray optical system. As described above, the observation of whether the sample 11 is located at the position where the light beams intersect is performed by, for example, using the C arranged in the space of the apparatus.
This is performed through an image from the CD camera 5. Hereinafter, the above configuration will be described in detail, and a procedure for adjusting the positions of the first and second laser light sources 2 and 4 to be performed at the time of assembling or maintenance of the apparatus will also be described. The proportional counter tube 6 is filled with argon gas, and an X-ray incidence window 8 for receiving X-rays is formed of a 1 μm-thick polymer film supported by an optically transparent stainless steel mesh. Have been. An optical window 7 is provided at a position facing the X-ray incident window 8, and laser light from the first laser light source 2 passes through the optical window 7 and the X-ray incident window 8 to perform the proportional counting. The light is emitted toward the spectral crystal 3 coaxially with the optical axis of the X-ray with respect to the tube 6. In this case, the first laser light source 2 corresponds to a first visible light source.

On the other hand, the second laser light source 4 is provided at a position where the laser light from the first laser light source 2 can be irradiated from a different direction. Continue with the first
The procedure for adjusting the second laser light sources 2 and 4 and the spectral crystal 3 will be described. First, because of the initial adjustment, to prepare a phosphor which emits visible light as a sample by irradiating an ion beam 1 _a. In this case, a phosphor may be applied to the surface of the sample 11 and used. When the ion beam _1a is irradiated, only the irradiated position emits light on the sample surface. Therefore, the light emission point and the light emission on the sample due to the irradiation of the first laser light source 2 with the laser light. The position of the proportional counter tube 6 is adjusted by moving the proportional counter tube 6 together with the laser light source 2 of the table 1 in, for example, the direction of the arrow 10 so that the points coincide. That is, the laser light emitted from the first laser light source 2 is reflected on the surface of the spectral crystal 3 and irradiates the sample surface. Here, the surface of the spectral crystal 3 is mirror-finished in advance to prevent parasitic scattering of X-rays. Similarly, a laser beam from the second laser light source 4 is irradiated,
The position of the second laser light source 4 is adjusted so as to be located at the light emitting point on the sample surface. Note that whether or not the light emitting points match as described above is performed through the image from the CCD camera 5.

As described above, the first and second laser light sources 2 and 4 are positioned with respect to the focal position of the X-ray optical system. Further, in order to obtain the best wavelength resolution for the intended X-ray spectroscopy, the above-mentioned crystallographic crystal 3 is rotated and adjusted in the direction of arrow 9 and the first laser light source 2 and the The proportional counter 6 is moved.
Thereby, the distance from the irradiation point of the ion beam 1 _a to the spectral crystal 3 is adjusted. Here, the above-mentioned spectral crystal 3
The angle of incidence of X-rays on the substrate may be adjusted so as to operate within a range of ± 1 to 2 degrees around the angle given by the equation (1). Thus, when the spectral X-ray, is always moved proportional counter 6 with respect to the analyzing crystal 3 such that the first position in which the laser light source 2 irradiates the sample 11 coincides with the irradiation point of the ion beam 1 _a It is possible to adjust the optical axis and the focal position in the X-ray optical system very easily while maintaining the accuracy. When a sample is analyzed by the apparatus adjusted as described above, first, the sample 11 is placed on the goniometer head 13 in a vacuum through the load lock mechanism 12. Subsequently, the sample 11 is irradiated with laser light from the first and second laser light sources 2 and 4, and the goniometer 1 is set so that the two light emitting points on the sample 11 coincide.
4 to operate in the Z-axis direction (direction of irradiation of the ion beam 1 _a). As described above, the position of the sample 11 can be adjusted to the focal position of the X-ray optical system.

[0011] positioning of the sample 11 as described above is completed, the first, the irradiation of the second of the laser light source 2 and 4 is stopped, starts the irradiation of the ion beam 1 _a from the radiation source 1 . Then, as in the case of the above-described initial adjustment, the dispersive crystal 3 is rotated in the direction of arrow 9 and the proportional counter tube 6 and the first laser beam 2 are moved with this operation. Here, since the X-ray having a wavelength different for each element is irradiated with the ion beam 1 _a occurs, determine the angle corresponding to the wavelength of X-rays of the elements to be analyzed according to the equation (1), this angle Is rotated so that the incident angle and the reflection angle of the X-rays with respect to the spectral crystal 3 coincide with each other within a range of 1 to 2 degrees, and the proportional counter tube 6 and the first Is moved.
For example, when performing qualitative analysis of oxygen (presence or absence of oxygen), the wavelength of X-rays specific to oxygen is 23.62 °, and when an artificial multilayer film having a lattice spacing of 40 ° is used as the spectral crystal 3, X The incident angle of the line is given by n
= 1 gives a value of 17.2 degrees. Therefore, it is sufficient to rotate the dispersive crystal 3 so that the value of the incident angle falls within the range of 16.2 to 18.2 degrees. FIG. 2 shows the result of analysis of oxygen in zinc silicate by the apparatus. In this case, as an analysis target, in addition to oxygen X-rays (OKα), X-rays generated by zinc (ZnLα) are observed as disturbing X-rays. Are observed with sufficient wavelength resolution, indicating that the focal point adjustment in the X-ray optical system is performed with sufficient accuracy in the apparatus.

The X-ray spectroscopy according to the embodiment shown in FIG.
In the apparatus A, in addition to the above-mentioned spectral crystal 3, a recoil ion
Analyzer 15, energy dispersive X-ray spectrometer 16, secondary
Equipped with an electronic detector 17 etc. to analyze the sample from multiple sides
can do. Further, the X-ray spectroscopy apparatus according to the above-described embodiment.
In the arrangement, the radiation source 1 is used as the second beam irradiation means.
Used, omitting the second laser light source 4, and
Simplification can also be achieved. In this case, a dummy
Phosphor is applied to the surface of the material as
_aPoint from the first laser light source 2
The goniometer 14 is adjusted so that the light emission point of the
Adjust the position. Then, the position is adjusted to this adjusted position.
Replace the sample to be analyzed with the dummy
The position is adjusted by the
Beam 1_aIrradiates the specified analysis.
It is possible. FIG. 3 shows another embodiment of the present invention.
1 shows such an X-ray spectrometer B. X-ray spectroscopy according to this embodiment
Apparatus B converts radiation 27 from radiation source 20 to sample 11
Irradiation and analysis of X-rays generated from this sample 11
It was made. That is, in the X-ray spectrometer B, radiation
Radiation 27 generated from the source 20 is collimated by the collimator 21.
Thus, the sample 11 is irradiated. Release
X-rays 28 generated from the sample 11 irradiated with the radiation 27
The light is separated by the spectral crystal 31 and the semiconductor detector 29 (X-ray detection)
Container). For example, a silicon
A single crystal such as silicon or germanium is used.

Between the radiation source 20 and the collimator 21 and between the spectral crystal 31 and the semiconductor detector 29, polymer thin films 24 and 25 on which aluminum as an example of a light metal element thin film is deposited are disposed. ing. The laser light source 22 (second light beam irradiating means, second visible light source) and the laser light source 23 correspond to the polymer thin films 24 and 25, respectively.
(First light irradiating means and first visible light source) are provided respectively, and laser light 2 from laser light sources 22 and 23 is provided.
6, 35 are guided to the optical axis of the X-ray optical system. Here, also in the X-ray spectrometer B, the laser light sources 22, 2 are operated in the same procedure as in the case of the X-ray spectrometer A.
3. The position of the spectral crystal 31 and the semiconductor detector 29 is adjusted, and the laser light source 23 and the semiconductor detector 29 are moved together with the polymer thin film 25 by an arm that swings in conjunction with the rotation of the spectral crystal 31. 19 supported. In this device, a CCD for further observing the sample surface
In order to prevent unnecessary irradiation of camera 33 and radiation,
A shutter 34 is provided in front of the radiation source 20.

In order to prevent exposure to radiation, the entire apparatus is housed in a shielding box 30 to enable measurement in the atmosphere. Here, the thin aluminum sufficiently transmits X-rays generated by an element heavier than phosphorus. For example, for a 0.4 μm thick aluminum, 16% of X-rays that generate phosphorus and 40% of X-rays that generate argon
To Penetrate. For elements heavier than this, the transmittance further increases, indicating that there is sufficient transmittance during the analysis. Further, the polymer film absorbs less X-rays than aluminum and does not affect the analysis. Therefore, when the laser light sources 22 and 23 emit laser light 26 and 35, the laser light is reflected by the polymer thin films 24 and 25 on which aluminum is deposited, and is introduced along the optical axis of the X-ray optical system. Further, one laser beam 26 is emitted from the collimator 21.
The sample 11 is irradiated through the slit of FIG. The other laser beam 35 is reflected on the mirror-polished surface of the spectral crystal 31 and irradiates the sample 11. Both laser beams 2
The CCD cameras 33 and 35 are previously adjusted so as to intersect at the focal position of the X-ray optical system.
When the position of the sample 11 is adjusted so that the positions where the two laser beams 26 and 35 irradiate the sample surface coincide with each other while observing the sample surface, the adjustment of the focal position of the sample 11 in the X-ray optical system is completed. Then, before the measurement, the rotating stage 3
2 is rotated, the orientation of the dispersive crystal 31 is adjusted to an angle corresponding to the wavelength of the X-rays to be disperse according to the above equation (1), and the dispersive crystal 31 is supported by the arm 19 at a corresponding position in conjunction therewith. The semiconductor detector 29 is moved. This arm 1
9 includes the semiconductor detector 29 and the laser light source 2.
3. The polymer thin film 25 is also supported.

When the incident angle of X-rays on the spectral crystal 31 is changed in this way, the focal length of the X-ray optical system also changes, so that the distance between the spectral crystal 31 and the sample 11 can be adjusted. . At this time, the laser light sources 22 and 23 are operated again to confirm the focal position. Thus, the adjustment in the X-ray optical system is completed, the shutter 34 is opened and the radiation 27 is released.
Is irradiated, and the amount of X-rays dispersed by the spectral crystal 31 is measured by the semiconductor detector 29. As described above, also in the X-ray spectroscopy apparatus B in the present embodiment, similarly to the case of the above-described X-ray spectroscopy apparatus A, it is possible to extremely easily adjust the focal position in the X-ray optical system. Further, the position of the semiconductor detector 29 with respect to the sample 11 can be easily adjusted.

[0016]

As described above, according to the present invention, a radiation source irradiates a sample whose position has been adjusted by the position adjusting mechanism to the focal position of the X-ray optical system, and X-rays from the sample are irradiated.
In a wavelength dispersive X-ray spectrometer that splits a ray with a diffractive spectroscope and then detects the ray with an X-ray detector, first and second irradiating light rays from different directions so that an optical path intersects at the focal position. A wavelength dispersive X-ray spectrometer, wherein the sample is positioned at a position where the optical path intersects by driving the position adjusting mechanism. The adjustment of the position of the sample to the focal position of the system can be performed with a relatively simple configuration. Further, by adopting the above configuration, it becomes possible to install another detector or the like by making the entire apparatus compact or saving space.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an X-ray spectrometer according to one embodiment of the present invention.

FIG. 2 is a graph showing a result of analyzing zinc silicate by the X-ray spectrometer.

FIG. 3 is a schematic configuration diagram of an X-ray spectrometer according to another embodiment of the present invention.

FIG. 4 is a diagram illustrating the principle of a wavelength dispersion type X-ray spectrometer.

FIG. 5 is a view for explaining a sample position adjusting mechanism in a conventional wavelength dispersion type X-ray spectrometer.

[Explanation of symbols]

1,20 ... radiation source 1 _a ... ion beam 2 ... first laser light source (first light beam irradiation means) 3, 31 ... analyzing crystal (spectrometer) 4 ... second laser light source (second light emitting means 6 ... Proportional counter tube (X-ray detector) 11 ... Sample 14 ... Goniometer (position adjustment mechanism) 22 ... Laser light source (second light irradiation means, second visible light source) 23 ... Laser light source (first light beam) Irradiation means, first visible light source) 24, 25 ... polymer thin film 26, 35 ... laser beam 27 ... radiation 28 ... X-ray 29 ... semiconductor detector (X-ray detector) A, B ... X-ray spectrometer

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Kazushi Yokoyama 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Kobe Steel, Ltd. Kobe Research Institute (56) References JP-A-4-285847 (JP, A) JP-A-2-38851 (JP, A) JP-A-5-72149 (JP, A) JP-A-4-341740 (JP, A) JP-A-63-149058 (JP, U)

Claims (5)

(57) [Claims] 1. A radiation source irradiates a sample whose position has been adjusted by a position adjustment mechanism to a focal position of an X-ray optical system, and X-rays from the sample are separated by a diffraction type spectroscope. , A wavelength dispersive X-ray spectrometer that detects light with an X-ray detector, comprising first and second light beam irradiating means for irradiating light beams from different directions so that optical paths intersect at the focal position. A wavelength-dispersive X-ray spectrometer, wherein a mechanism is driven so that the sample is located at a position where the optical paths intersect. 2. A first visible light source in which the first light beam irradiating means emits visible light from the X-ray detector side toward the spectroscope coaxially with the optical axis of the X-ray with respect to the X-ray detector. The wavelength dispersive X-ray spectrometer according to claim 1, wherein 3. The wavelength-dispersive X-ray spectrometer according to claim 1, wherein said radiation source is used as said second light beam irradiation means. 4. The wavelength-dispersive X-ray spectroscopy according to claim 1, wherein said second light beam irradiating means is a second visible light source for injecting visible light coaxially with an optical axis of radiation from said radiation source. apparatus. 5. The wavelength-dispersive X-ray spectrometer according to claim 2, wherein the first and / or second visible light source is a laser light source.