JP2000009666A - X-ray analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray analyzer wherein an elemental analysis and a structural analysis which measures a reflectance in a wide wavelength region can be performed simply by one analyzer. SOLUTION: An X-ray tube 4 by which a sample 1 or a target material 2 is irradiated with X-rays 3 is provided. A first sample base 5 to which the sample 1 or the target material 2 is fixed is provided. A spectral element 8 by which secondary X-rays 7 generated from the sample 1 are spectrally diffracted is provided. A second sample base 10 which is arranged selectively in the same position as the spectral element 8 and to which the sample 1 is fixed in such a way that characteristic X-rays 9 generated from the target 2 are incident is provided. A detector 18 by which the intensity of fluorescent X-rays 16 spectrally diffracted by the spectral element 8 or the intensity of the characteristic X-rays 9 reflected by the sample 1 is measured is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray analyzer that can easily perform elemental analysis and structural analysis with one unit.

[0002]

2. Description of the Related Art Conventionally, for example, a wavelength dispersive (angle scan) fluorescent X-ray analyzer has been used for qualitative or quantitative analysis of elements in a sample, and a reflectometer has been used for structural analysis of the sample. Is used.

[0003]

Therefore, in order to perform both elemental analysis and structural analysis on a certain sample, a dedicated apparatus was required for each analysis. Further, in the conventional reflectometer, the X-rays used are mainly Cu-Kα rays. Thus, for example, a single-layer thin film sample obtained by sputtering a 200-nm-thick carbon film on a silicon wafer is reflected. When the rate measurement is performed, as shown in FIG. 7, the vibration state of the interference by the thin film is very weak, and the periodic angle of the vibration is a very small value of about 0.018 degrees. In order to read this angle with an effective precision of 1/100, it is necessary for the apparatus to have a precision of about 0.0001 degrees, which is difficult to achieve.

Similarly, for example, a silicon wafer having a thickness of 2
A multilayer thin film sample in which a nickel film of 8 nm and a carbon film of 8 nm in thickness are alternately laminated by 20-layer sputtering is also provided.
As shown in FIG. 8, the peak angle for determining the period length of the multilayer structure has a small value of 0.504 degrees. That is, it is difficult to analyze such samples with high accuracy. On the other hand, if reflectance measurement is performed in the soft X-ray region, highly accurate analysis is possible.
It could only be performed with limited special equipment such as SR light facilities.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an X-ray analysis apparatus which can easily perform elemental analysis and structural analysis by measuring reflectance in a wide wavelength range with one unit. Aim.

[0006]

In order to achieve the above object, an X-ray analyzer according to the present invention comprises: an X-ray tube for irradiating a sample or a target material with X-rays; And a first sample stage to be used. Also,
A second dispersive element for dispersing secondary X-rays generated from the sample, and a second dispersive element selectively disposed at the same position as the dispersive element and fixing the sample such that the unique X-rays generated from the target material are incident thereon; A sample stage. Further, a detector is provided for measuring the intensity of the fluorescent X-ray separated by the spectroscopic element or the intensity of the specific X-ray reflected by the sample fixed to the second sample stage.

According to the X-ray analyzer of the first aspect, which of the sample and the target material is fixed to the first sample stage,
Also, depending on whether the spectroscopic element or the second sample stage is arranged in the X-ray optical path, it functions as both a fluorescent X-ray analyzer and a reflectometer, so that element analysis and structural analysis can be performed by one unit. It can be done easily. Further, when functioning as a reflectometer, an X-ray generated from an X-ray tube is not used as it is, but a specific X-ray generated by irradiating a desired target material is used. The reflectance measurement in a wide wavelength region including the line region can be easily performed.

An X-ray analyzer according to a second aspect of the invention includes an X-ray tube, a first sample stage, and a spectroscopic element similar to those of the first aspect. A second sample stage is provided at a different position from the spectroscopic element, and the sample is fixed so that the characteristic X-rays generated from the target material are incident thereon. Further, a first detector for measuring the intensity of the fluorescent X-rays separated by the spectroscopic element, and a second detector for measuring the intensity of the specific X-ray reflected by the sample fixed to the second sample stage And According to the X-ray analyzer of the second aspect, the same operation and effect as those of the apparatus of the first aspect can be obtained.

According to a third aspect of the present invention, there is provided the X-ray analyzer according to the first or second aspect, wherein the target material is plural.
Target material selecting means for driving the first sample stage to irradiate a desired target material with X-rays is provided. According to the X-ray analyzer of the third aspect, it is easy to select a desired target material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, X of a first embodiment of the present invention will be described.
The line analyzer will be described with reference to the drawings. First, the configuration of this device will be described. As shown in FIG. 1, this apparatus includes an X-ray tube 4 for irradiating a sample 1 or a target material 2 with X-rays 3, and a first sample stage 5 on which the sample 1 or the target material 2 is fixed. . Here, target material 2
Are a plurality, for example, those made of beryllium 2A,
A graphite sample 2B, a magnesium sample 2C, and a silicon sample 2D are fixed to the disk-shaped first sample table 5 in a circumferential direction, and the first sample table 5 is fixed.
Are irradiated with X-rays 3 by a target material selecting means 6 for driving the target materials 2A, 2B,... Around the central axis 5c.

The target material 2 may be made of boron, boron nitride, silicon nitride, silicon dioxide, lithium fluoride, sodium chloride, aluminum, or the like. It can be fixed to the sample table 5. Since the sample 1 is also fixed to the first sample stage 5, the target material selecting means 6 sets the first sample stage 5
Can be rotated to irradiate the sample 1 with the X-rays 3.

The apparatus according to the first embodiment includes a spectroscopic element 8 for dispersing the secondary X-rays 7 generated from the sample 1 and selectively disposed at the same position as the spectroscopic element 8. A second sample stage 10 to which the sample 1 is fixed so that the generated intrinsic X-ray 9 (FIG. 2) is incident thereon is provided. Specifically, for example, three types of spectroscopic elements 8A, 8B, and 8C are fixed to three continuous surfaces of the substantially cubic selecting means 11, and the fine movement mechanism 1 having a telescopic shaft 12a on the remaining one surface.
The second sample stage 10 is provided via 2 (incorporated inside the selecting means 11). Selection means 11
Are rotated about a central axis 11c perpendicular to the paper surface, and the secondary light generated from the sample 1 on the surface of the desired spectroscopic element 8A, 8B... Or the surface of the sample 1 (FIG. 2) fixed to the second sample stage 10. X
The line 7 or the specific X-ray 9 (FIG. 2) generated from the target material 2 is incident.

The apparatus according to the first embodiment is a solar slit 1 for collimating a secondary X-ray 7 generated from the sample 1 or a unique X-ray 9 (FIG. 2) generated from the target material 2.
3. As shown in FIG. 2, a parallel beam forming slit 1 for narrowing down the eigen X-rays 9 generated from the target material 2 or the eigen X-rays 17 reflected on the sample 1 fixed to the second sample stage 10
4A, 14B and the parallel beam forming slits 14A, 14 only if the device functions as a reflectometer.
B moves into the optical path and functions as an X-ray fluorescence analyzer (FIG. 1).
15B is also provided.

Further, the apparatus according to the first embodiment uses the intensity of the fluorescent X-rays 16 separated by the spectral element 8 in FIG.
Eigen-X-ray 1 reflected by sample 1 fixed to sample stage 10
7 (FIG. 2) is provided with a detector 18 such as an F-PC for measuring the intensity. The detector 18 has a solar slit at or near the entrance.

Here, for example, when the apparatus functions as an X-ray fluorescence spectrometer, in order to scan the incident angle θ to the spectroscopic element 8 within a predetermined range, the incident angle θ and the spectral angle (to the spectroscopic element 8) An interlocking means (not shown) such as a so-called goniometer is used so that the extension of the incident secondary X-ray 7 and the angle (2θ) formed by the separated fluorescent X-rays 16 interlock. Is rotated about an axis O perpendicular to the plane of the drawing passing through the center of the surface, and the detector 18 is rotated by a circle 19 about the common axis O by twice the rotation angle. Is rotated along. Similarly, as shown in FIG. 2, when the apparatus functions as a reflectometer, the sample 1 is scanned to scan a predetermined range of the incident angle θ with respect to the sample 1.
(Specifically, the entire selection means 11 having the second sample stage 10 to which it is fixed), the detector 18 and the parallel beam forming slit 14B are rotated in conjunction with each other by the linkage means.

Next, the operation of the X-ray analyzer of the first embodiment will be described. Now, it is assumed that the thin film sample 1 in which a thin film is formed on a substrate is first used to perform elemental analysis of the thin film and then to perform structural analysis of the thin film using this apparatus. Therefore,
As shown in FIG. 1, the sample 1 is fixed to the first sample stage 5, and the first sample stage 5 is driven to rotate by the target material selecting means 6 to position the sample 1 immediately below the X-ray tube 4. 3, the secondary X-rays 7 generated from the sample 1 are collimated by the solar slit 13 and the collimated secondary X-rays 7
Is incident on the spectroscopic element 8B selected by the selection unit 11 at the rotation center O by the interlocking unit, and is separated. The intensity of the separated fluorescent X-ray 16 is detected by the detector 18 at a predetermined incident angle θ. Measured sequentially over a range. That is, the element analysis of the thin film is performed on the thin film sample 1 in the same manner as in the conventional wavelength-dispersive X-ray fluorescence analyzer.

Next, when conducting a structural analysis of the thin film, as shown in FIG. 2, the sample 1 is fixed on the second sample stage 10, the selecting means 11 is rotated, and further according to the thickness of the sample 1. The shaft 1a of the fine movement mechanism 12 is extended and contracted to position the sample 1 such that the characteristic X-rays 9 generated from the target material 2 are incident on the surface of the sample 1 at the rotation center O by the interlocking means. Then, the target material selecting means 6 positions a desired target material 2B made of graphite, for example, immediately below the X-ray tube 4 and irradiates it with X-rays 3. The line 9 is collimated by the solar slit 13, a part of which passes through the parallel beam forming slit 14A inserted into the optical path by the advance / retreat means 15A, and the C-Kα line 9 passing therethrough
Is reflected (diffracted) by the sample 1 and passes through the parallel beam forming slit 14B, and its intensity is sequentially measured by the detector 18 within a predetermined incident angle θ range. That is, the reflectance measurement of the thin film sample 1 and the structural analysis of the thin film are performed.

At this time, since the X-ray used is C-Kα ray, the sample 1 is a silicon wafer having the same carbon single-layer film of 200 nm in thickness as described in the prior art. As shown in FIG. 5, compared with the conventional FIG. 7, the vibration state of the interference by the thin film is very strong (the amplitude is large), and the periodic angle thereof is 0.56 degrees, which is about 30 times larger than the conventional value. Becomes With this angle, the apparatus can be read with an effective accuracy of 1/100 with an accuracy of about 0.005 degrees.

Similarly, for example, when the sample 1 is a silicon wafer having 20 pairs of a nickel film having a thickness of 2 nm and a carbon film having a thickness of 8 nm, which is also the same as described in the related art. As shown in FIG. 6, the peak angle for determining the period length of the multilayer structure is 13.
It is 6 degrees, which is about 30 times as large as the conventional value. That is, highly accurate analysis is also possible for these samples 1.

As described above, according to the X-ray analyzer of the first embodiment, the sample 1 or the target material 2 is placed immediately below the X-ray tube 4.
Is located, and accordingly, either the spectroscopic element 8 or the sample 1 fixed to the second sample stage is set to X
Depending on the arrangement in the line optical path, it functions as both a fluorescent X-ray analyzer and a reflectometer, so that element analysis and structural analysis can be easily performed by one unit. Further, as shown in FIG. 2, when functioning as a reflectometer, the X-ray 3 generated from the X-ray tube 4 is not used as it is, but a desired target material 2 is used.
Since the unique X-rays 9 generated by irradiating A, 2B... Are used, selection of the target materials 2A, 2B... Can be performed in a wide wavelength region including a soft X-ray region without using a special device such as an SR light facility. The reflectance measurement can be performed easily. Further, selection of desired target materials 2A, 2B,... By the target material selecting means 6 is easy.

Next, an X-ray analyzer according to a second embodiment of the present invention will be described with reference to the drawings. In this apparatus, as shown in FIG. 3, the second sample stage 20 is arranged at a position different from the spectral element 8, and the detector 28 also measures the intensity of the fluorescent X-ray 16 spectrally separated by the spectral element 8. Apart from the first detector 28A,
Eigen X reflected by sample 1 fixed to second sample stage 20
A second detector 28B for measuring the intensity of the line 17 (FIG. 4) is provided, and an interlocking means such as a goniometer is provided for each detector 28B.
The apparatus is different from the apparatus of the first embodiment in that the apparatus is provided for each of A and 28B, but the other points are the same and the description is omitted. Specifically, the selection means 2
1 has a surface 21a for retreating from the X-ray optical path, and as shown in FIG. 4, in the traveling direction of the unique X-ray 9 generated from the target material 2 and passing in front of the retreating surface 21a,
Separately from the selection means 21, the telescopic shaft 2 of the fine movement mechanism 22
A second sample stage 20 supported by 2a is provided.

When elemental analysis is performed on the sample 1 using this apparatus, as shown in FIG.
The next X-ray 7 is the spectroscopic element 8 selected by the selection unit 21.
To B, is spectrally incident in the rotation center O _A by interlocking means, the intensity of the fluorescent X-ray 16 that is the spectroscopy, the detector 28A, are sequentially measured in the range of a predetermined angle of incidence theta,
The elemental analysis is performed on the sample 1 as in the apparatus of the first embodiment.

When performing a structural analysis of the sample, as shown in FIG. 4, the selecting means 21 is rotated to retreat from the X-ray optical path, the sample 1 is fixed to the second sample stage 20, and the sample 1 is further fixed.
By extending and contracting the shaft 22a of the fine movement mechanism 22 according to the thickness of
Characteristic X-ray 9 generated from the target material 2, the surface of the sample 1, to be incident in the rotation center O _B by interlocking means, to position the sample 1. Then, the target material selection means 6 positions the desired target material 2B immediately below the X-ray tube 4 and irradiates the target with the X-rays 3.
X-rays 9 generated from the laser beam are collimated by the solar slit 13, and a part thereof passes through the parallel beam forming slit 14 A inserted into the optical path by the advance / retreat means 15 A. Are reflected (diffracted) by the laser beam, pass through the parallel beam forming slit 14B, and the intensity thereof is sequentially measured by the detector 28B in a range of a predetermined incident angle θ. That is, the reflectance measurement of the sample 1 and the structural analysis are performed.

According to the apparatus of the second embodiment, the first
The same operation and effect as those of the device of the embodiment can be obtained. In the apparatus of the second embodiment, the reciprocating means 15B on the detector 28B side is unnecessary, and the parallel beam forming slit 14B on the detector 28B side may be fixed to the detector 28B.

[0025]

As described in detail above, the X of the present invention
According to the X-ray analyzer, the fluorescent X-rays are determined depending on whether the sample or the target material is fixed to the first sample stage and whether the spectroscopic element or the second sample stage is arranged in the X-ray optical path accordingly. Since it functions as both an analyzer and a reflectometer, element analysis and structural analysis can be easily performed by one unit. Further, when functioning as a reflectometer, an X-ray generated from an X-ray tube is not used as it is, but a specific X-ray generated by irradiating a desired target material is used. The reflectance measurement in a wide wavelength region including the line region can be easily performed.

[Brief description of the drawings]

FIG. 1 shows an X-ray analyzer according to a first embodiment of the present invention.
It is the schematic which shows the state which functions as a fluorescent X-ray analyzer.

FIG. 2 is a schematic diagram showing a state in which the device functions as a reflectometer.

FIG. 3 shows an X-ray analyzer according to a second embodiment of the present invention;
It is the schematic which shows the state which functions as a fluorescent X-ray analyzer.

FIG. 4 is a schematic diagram showing a state in which the device functions as a reflectometer.

FIG. 5 is a view showing a measurement result of a reflectance of a sample having a single-layer thin film by the apparatus of the first embodiment.

FIG. 6 is a diagram showing a measurement result of the reflectance of a sample having a multilayer thin film by the same device.

FIG. 7 is a diagram showing a measurement result of the reflectance of a sample having a single-layer thin film by a conventional reflectometer.

FIG. 8 is a view showing the measurement results of the reflectance of a sample having a multilayer thin film by the reflectometer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample, 2 ... Target material, 3 ... X-ray irradiated from X-ray tube, 4 ... X-ray tube, 5 ... First sample stage, 6 ... Target material selection means, 7 ... Secondary X generated from sample Line, 8: spectral element, 9: intrinsic X-ray generated from the target material, 10,
20: second sample stage, 16: X-ray fluorescence X-ray, 17 ...
Reflected characteristic X-rays, 18, 28 ... detector.

Claims (3)

[Claims] An X-ray tube for irradiating a sample or a target material with X-rays, a first sample stage on which the sample or the target material is fixed, a spectroscopic element for separating secondary X-rays generated from the sample, A second sample stage which is selectively arranged at the same position as the spectroscopic element and on which the sample is fixed so that the characteristic X-rays generated from the target material are incident thereon, the intensity of the fluorescent X-rays dispersed by the spectroscopic element Or a detector for measuring the intensity of the intrinsic X-ray reflected by the sample fixed to the second sample stage. 2. An X-ray tube for irradiating a sample or a target material with X-rays, a first sample stage on which the sample or the target material is fixed, a spectral element for splitting secondary X-rays generated from the sample, A second sample stage which is arranged at a position different from the spectroscopic element and on which the sample is fixed so that the characteristic X-rays generated from the target material are incident thereon, and the intensity of the fluorescent X-rays separated by the spectroscopic element An X-ray analyzer comprising: a first detector for measuring; and a second detector for measuring the intensity of the characteristic X-ray reflected by a sample fixed to the second sample stage. 3. The X-ray analyzer according to claim 1, wherein the target material is plural, and a target material selecting unit that drives the first sample stage to irradiate a desired target material with X-rays. .