JPH07140093A - X-ray evaluation equipment - Google Patents

Abstract

PURPOSE:To perform structural analysis easily and accurately by carrying out measurements such as XANES (X-ray absorption fine structure method) or XPS (photoelectron spectroscopy), etc., as well as other measurements at the same time. CONSTITUTION:An X-ray evaluation equipment includes within a vacuum chamber 2, an X-ray source 4, an X-ray spectroscope 7 for separating the X-ray generated by the X-ray source 4, a hollow quartz fiber 16 having flexibility that partly separates and extracts the X-ray that is separated by the spectroscope 7 and goes straight, a manipulator 9 for holding a specimen 8 and moving it relatively, a first detector 13 that detects the X-ray that is separated by the spectroscope 7, goes straight and then reflected on the specimen 8, and a second detector 18 that detects the X-ray that is bent by the fiber 16 after it is separated by the spectroscope 7 and is transmitted through the specimen 8. Further, it is constructed in a manner that multiple information will be obtained at the same the while evaluating one specimen 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray evaluation apparatus for evaluating the atomic and electronic structures of various organic and inorganic substances using X-rays.

[0002]

2. Description of the Related Art In recent years, research and development of device materials having new functions have been actively conducted, and composition or structure analysis of material surfaces has become important.

As a method for evaluating the surface atomic / electronic structure of such a substance, there are many methods using an electron beam, an X-ray, a neutron beam, an ion beam or the like as a probe (excitation source).
For example, as an electron beam, a transmission microscope (TEM) that analyzes an atomic arrangement, a defect structure, an interface structure or the like by using a detected amount as a transmitted electron, or a reflection microscope that analyzes a surface atomic structure or the like by using a detected amount as a reflected electron ( REM). In addition, as X-ray analysis, photoelectron spectroscopy (XPS = X-ray) is used to analyze band structure, density of states distribution, chemical bond state, etc., using the detected amount as electrons (energy spectrum).
Photoelectron Spectroscopy) or X-ray analysis method or extension to analyze the crystal structure or local atomic structure (interatomic distance) by detecting X-rays (diffraction, standing wave, absorption fine structure) and fluorescent X-rays (energy spectrum). X-ray absorption fine structure method (EXAFS = Extended X-ray Absorption)
Fine Structure) etc.

Of these probes, electron beams other than X-rays, neutron beams, ion beams, etc. generally have the drawback of being easily absorbed and scattered in air. Therefore, in many cases other than these X-rays, the sample is placed in a vacuum for evaluation. In this respect, X-rays are promising because they are hardly absorbed or scattered even in air. However, even in the X-ray,
X-rays of several tens of liters or more, which are called soft X-rays, are easily absorbed and scattered in the air, and therefore a vacuum chamber is often used as used in the XPS method.

[0005] Here, in the case of using any of these probes (light / electrons), various researches and developments have been made on a method of making light / electrons incident on the surface of the sample in a grazing manner to obtain information on the uppermost surface layer. There is. For example, there is a total reflection X-ray fluorescence analysis method. Among these, surface analysis methods using X-rays, which are considered promising as described above, include surface fluorescence EXAFS method and total reflection X-ray measurement method. All of these are intended to evaluate the atomic / electronic structure of the sample surface, surface / interface roughness, density, film thickness, etc. by making X-rays incident on the sample surface at a grazing low incident angle. is there. In this case, conventionally, hard X-rays having a wavelength of several Å or less are mainly used.

By the way, the transition from the core level to the vacant level of elements such as C, N and O which form the organic film is 300 to 700e.
It is in the soft X-ray region of about V. Various structures appear in the soft X-ray absorption spectrum due to these transitions, but the X-ray absorption edge fine structure method (XANES = X-ray Absorption Near-Edge) appears from near the absorption edge to above several tens of eV.
Structure) is effective for identifying functional groups existing in the film and analyzing molecular orientation.

As a measurement light source for such XANES, the synchrotron radiation (SO
R) is used only as a single color. Moreover, since the emitted light is an excellent polarized light, the anisotropy of absorption can also be measured. In addition to this, as a typical structural analysis method using soft X-rays, there is the photoelectron spectroscopy XPS as described above.

Here, the emitted light is 1000 to 10000 times stronger than the target method used in the laboratory and can handle polarized light. Therefore, in the conventional case, as described above, the soft X It was the only one used for XANES measurements in the linear region. In this respect, according to the present inventors, it is possible to perform sufficient measurement even in a laboratory system by measuring a soft X-ray with a high-level detector for a long time, and to measure the polarization of the soft X-ray. In such a case, it has been found that even a laboratory system device can be sufficiently handled by using a multi-layer film reflecting mirror, and an invention of an X-ray evaluation device for implementing it has been proposed.

One of them is, for example, Japanese Patent Application No. 4-24.
According to No. 9331, an X-ray source, an X-ray spectroscope that disperses X-rays from the X-ray source, a manipulator that holds a sample, and an X-ray from the X-ray spectroscope with respect to the sample. Total reflection mirror with variable incident angle, two-dimensional detector for detecting X-ray and electron beam emitted from the sample, X-ray source, X-ray spectroscope, sample, manipulator, and total reflection mirror. An X-ray evaluation apparatus has been proposed which is composed of a vacuum chamber having a built-in detector and a two-dimensional detector.

[0010]

In the conventional apparatus including the evaluation apparatus using X-rays as shown in this proposal example, the X-rays emitted from the X-ray source may or may not be dispersed. The light is incident on the sample as one light beam and is reflected or absorbed / diffracted to obtain structural information of atoms and electrons.

That is, it has only a single purpose and a single evaluation.

Even with such a single purpose and evaluation,
This in itself is not a drawback. However, in future thin film materials, we will design atomic and electronic structures, design and create new functions, or make evaluations while making them on the spot, and feed back the analysis results to make them while controlling the structure. Given that it is becoming more important to be able to move forward, conventional single evaluation is not enough.

That is, the structure of a material under certain conditions is
If it is complicated and more multi-dimensional information can be obtained, structural analysis will be easier, accurate and faster. In addition, the multi-dimensional information is not limited to that, and an effect of calibrating two or more pieces of information can be obtained. For example, atomic coordinate information obtained from X-ray diffraction and X-ray absorption (for example, EXAF)
By simultaneously obtaining atomic coordinate information obtained from
The length of each piece of information can be compared and mutually corrected. Further, it is possible to obtain information from the surface of the material by utilizing the surface reflection and at the same time obtain information from the average value of the material by transmitting the information through the film. According to the X-ray evaluation apparatus capable of having such a function, structural analysis becomes easy and accurate, and therefore its proposal is awaited.

[0014]

According to a first aspect of the present invention, an X-ray source, an X-ray spectroscope that disperses the X-rays from the X-ray source, and the X-ray spectroscope disperses light to go straight. A flexible hollow quartz fiber that separates and extracts a part of X-rays, a manipulator that holds and relatively moves a sample, and the X-ray spectroscope disperses the light into a straight line and reflects the sample. A first detector that detects X-rays, a second detector that detects X-rays that are separated by the X-ray spectroscope, bent by the hollow quartz fiber, and transmitted through the sample, and these X-ray sources and X-rays. It is composed of a line spectrometer, a hollow quartz fiber, a sample, a manipulator, a vacuum chamber containing a first detector and a second detector.

According to a second aspect of the invention, the X-ray spectroscope according to the first aspect of the invention is a monochromator in which channel-cut crystals are arranged (+, +) in an interlocking manner.

[0016]

According to the invention of claim 1, X-rays emitted from one X-ray source are separated by an X-ray spectroscope, and then a part is taken out by using a flexible hollow quartz fiber.
Since it is separated into the X-ray that goes straight to the sample and the X-ray that goes through the hollow silica fiber and is bent toward the sample, multiple information can be obtained at the same time in the evaluation of one sample, and the structural analysis becomes easy and accurate. In addition, the speed of measurement and evaluation can be improved, and mutual confirmation of a plurality of information can be simultaneously performed on the same sample. At this time, the wavelength of X-rays that can bend the optical path by the hollow quartz fiber is longer than that of normal X-rays, and it is applicable to soft X-rays. Therefore, X-rays incident on the sample through the hollow quartz fiber are soft X-rays. Although it is limited to X-rays, X-rays that enter the sample straight from the X-ray source are analyzed and evaluated by simultaneously using a hard X-ray with a wavelength of about 10 Å or less that is spectrally dispersed after the sample is incident. It is also possible to do.

If the X-ray spectroscope has one or two flat plate monochromators, the divergence of X-rays cannot be prevented.
X-rays with good parallelism cannot be obtained in the laboratory. By the way,
In SOR, parallelism is obtained and the spectral property is good, but the optical path changes (that is, moves) with one channel cut monochromator. In this respect, in the invention according to claim 2, the X-ray spectroscope analyzes the channel-cut crystal into (+,
+) Because it is arranged and interlocked with the monochromator, X
Line divergence is small and parallelism is good, and continuous spectroscopy is possible and energy resolution is good.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. First, a vacuum chamber 2 that communicates with the vacuum exhaust device 1 and has a high vacuum state inside is provided. This vacuum chamber 2 has diamond windows 3a and 3b with a thickness of 200 liters.
The X-ray source 4 region partitioned by and the spectral region are connected in series, and a slit (depending on the purpose, depending on the purpose,
A spectroscopic chamber 6 is built in together with the pinhole 5), and a channel cut monochromator 7 serving as an X-ray spectroscope is built in the spectroscopic chamber 6. In the original vacuum chamber 2, a sample 8 to be measured is held downward by a rotatable manipulator 9, and X-rays which are spectrally separated by the channel cut monochromator 7 and emitted through a diamond window 3b are sampled. 8 Total reflection mirror 1 that makes a low incidence angle incident on the surface 1
0 is provided. This total reflection mirror 10 has a rotating shaft 1
It is rotatable about 1, and is set so that the incident angle with respect to the sample 8 can be changed. Also, a total reflection mirror 1
A small ion chamber 12 for measuring the intensity of incident X-rays on the sample 8 is provided on the optical path between 0 and the sample 8. Furthermore, there is 2 in the optical path on the exit side from the sample 8.
A dimension detector (first detector) 13 is provided. In addition, in this embodiment, in order to enable analysis during film formation, a K cell 14 as a film forming device is provided below the sample 8. Reference numeral 15 is the shutter.

Although such a configuration is equivalent to that proposed by the present applicant described above, in the present embodiment, a part of the X-ray that is split by the channel cut monochromator 7 and goes straight is described above. There is provided a flexible hollow quartz fiber 16 that allows the sample 8 to pass through without being incident on the total reflection mirror 10 and by being extracted and bent and incident on the sample 8. Such a hollow quartz fiber 1
6 is, for example, the document “Optics” (Vol. 15, No. 2, 198).
As shown in “Limitation of Soft X-ray Transmission Characteristics and Transmittance of Hollow Quartz Fiber” (p. 235 to 240) in 6), bend light with a wavelength of about 25 to 75Å by 90 ° and guide it. Is possible. Specifically, inner diameter 0.2m
The length is 200 m and the length is 200 mm. A small ion chamber 17 for measuring the intensity of incident X-rays is also provided at the entrance of such a hollow quartz fiber 16. Further, on the transmission side optical path from the sample 8, a two-dimensional detector (second
A detector) 18 is provided.

Here, each part will be described. First, X
As the radiation source 4, it is preferable to use a rotor target mainly used in a laboratory, but a source called a plasma X-ray source or a laser X-ray source, or a sealed tube type may be used. However, considering simplicity and ease of use, W (tungsten), Mo (molybdenum), Ag
A rotor target using (silver), Al (aluminum) or the like and using white X-rays generated by irradiating an electron beam is preferable. In the present embodiment, for example, a rotor target that targets Mo is used.

The degree of vacuum in the vacuum chamber 2 is 10 to ⁶ Torr.
As described above, a high vacuum of 10 to ⁹ Torr or more is preferable, and an ultrahigh vacuum of 10 to ¹⁰ Torr or more is more preferable. On the other hand, the degree of vacuum in the spectroscopic chamber 6 is set to 10 ⁴ Torr or more.

The channel-cut monochromator 7 serving as an X-ray spectroscope is a channel-cut crystal, here, ADP.
(Ammonium dihydrogen phosphate = NH ₄ H ₂ PO ₄ ) The crystals are arranged (+, +) so as to interlock with each other.
The X-ray limited by the slit 5 is reflected by four spectroscopic crystals four times to disperse the X-ray. As the crystal for spectroscopy, Si (111), Ge (440), E
DOP, PET, SiO ₂ , InSb, LiF, TA
It may be P, RAP or the like.

The total reflection mirror 10 totally reflects X-rays, and it is desirable that the surface unevenness be 15 Å or less. As the material, carbon, BN, SiC or the like is used. In this embodiment, it is made of carbon, for example.
Further, when the concave mirror shape is used, the separated X-rays can be condensed and the intensity of the incident X-rays can be improved. Such a total reflection mirror 10 has 0.0
It is possible to rotate in increments of 01 deg, and fine adjustment of the incident angle is possible.

The two-dimensional detectors 13 and 18 are a PSD (semiconductor position detecting element) and a micro channel plate (MCP).
And an assembly having a diameter of 70 n, such as PIAS-TI manufactured by Hamamatsu Photonics KK
It is a small one with m and length of about 50 nm. Therefore, the internal arrangement in the ultra-vacuum vacuum chamber 2 is not hindered, and the spatial resolution as well as the temporal resolution is 10
Since it is as fast as 0 ps, it is possible to sufficiently evaluate the structural change of the substance during film formation.

In such a structure, for example, the sample 8
After forming a film by using the K cell 14, the X-ray from the X-ray source 4 is made incident on the surface of the sample 8 at a low incident angle (10 degrees or less), and the transmission XANES and the reflection XANES are measured. Think

First, the white X-ray emitted from the X-ray source 4 is limited by the slit 5, and then reflected by four crystals of the channel-cut monochromator 7 four times to be dispersed. A part of the separated X-rays are totally reflected by the total reflection mirror 10 to bend the optical path and enter the surface of the sample 8 at a low incident angle. At this time, the total reflection mirror 10 can rotate, and the incident angle on the sample 8 can be adjusted.

On the other hand, the rest of the X-rays dispersed by the channel cut monochromator 7 enter the hollow quartz fiber 16, are bent along the hollow quartz fiber 16 and then enter the sample 8 in a substantially vertical state. By this sample 8
To the two-dimensional detector 18 after being partially attenuated.

The intensities of the X-rays incident on the surface of the sample 8 by the total reflection mirror 10 and the X-rays incident on the hollow quartz fiber 16 are measured by the ion chambers 12 and 17, respectively. A part of the X-ray incident on the surface of the sample 8 is absorbed, but most of it is reflected and enters the two-dimensional detector 13. On the other hand, the X-rays whose optical path is bent by the hollow quartz fiber 16 and transmitted through the sample 8 enter another two-dimensional detector 18.

However, since the X-rays that are transmitted are limited to the range in which the optical path can be bent by the hollow quartz fiber 16, the wavelength becomes longer. As a result, the permeability is reduced, so it is ideal that there is no substrate used for sample 8, but a substrate is indispensable for evaluating the material structure during film formation. Therefore, in practice, 100
It can be said that it must be composed of elements as thin as 0 Å or less and as light as an organic film. Therefore, in this embodiment, a substrate made of an amorphous BN film having a thickness of 200Å is used.

Specifically, such amorphous BN
The p-terphenyl film is formed on the substrate by the film, 270
The XAFS spectrum was obtained by a reflection method by irradiating the film surface with X-rays dispersed at 320 eV (wavelength about 40 Å) at a low incident angle. A predetermined conversion program from reflection data to absorption data prepared in advance (for example, B. Pouml at Bud University in Paris)
lec, et al., (see JOGGING II being prepared) was evaluated, and an absorption spectrum as shown in FIG. 2 was obtained. At the same time, the hollow quartz fiber 16
When an absorption spectrum of X-rays incident almost perpendicularly to the film surface was obtained by, the spectrum was almost the same as that shown in FIG. 2, the above conversion program was correct, and the 1s → π ^ * transition I was able to confirm the condition.

By the way, in the present embodiment, all are arranged in the vacuum chamber 2 in order to handle soft X-rays.
When a strong X-ray such as R is used, it may not be necessarily arranged in the vacuum chamber 2 but can be adapted by shortening the optical path.

[0032]

According to the first aspect of the present invention, an X-ray source, an X-ray spectroscope that disperses the X-rays from the X-ray source, and an X-ray that is spectroscopically dispersed by the X-ray spectroscope and travels straight. , A flexible hollow quartz fiber for separating and extracting a part of the X-ray, a manipulator for holding and moving the sample relative to each other, and an X-ray spectroscopically separated by the X-ray spectroscope and traveling straight and reflected by the sample. A first detector for detecting X-rays, a second detector for detecting X-rays separated by the X-ray spectroscope, bent by the hollow quartz fiber and transmitted through the sample, X-ray sources and X-ray spectroscopy And a hollow quartz fiber, a sample, a manipulator, a vacuum chamber containing a first detector and a second detector, and X-rays emitted from one X-ray source are separated by an X-ray spectroscope. Uses a flexible hollow quartz fiber By taking out a part, since the bent through an X-ray and hollow silica fiber straight manner towards the sample was set to be separated into the X-ray toward the sample, 1
Multi-dimensional information can be obtained at the same time in the evaluation of one sample, structural analysis can be easily and accurately performed, the speed of measurement and evaluation can be improved, and mutual confirmation of a plurality of information can be simultaneously performed in the same sample.

In this case, according to the invention of claim 2, X
Since the line spectroscope is a monochromator that interlocks by arranging (+, +) arrangements of channel-cut crystals, X-ray divergence is small and parallelism is good, and continuous spectroscopy is also possible and energy resolution is high. Can be good.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an absorption spectrum.

[Explanation of symbols]

 2 vacuum chamber 4 X-ray source 7 monochromator (X-ray spectroscope) 8 sample 9 manipulator 13 first detector 16 hollow silica fiber 18 second detector

Claims (2)

[Claims] 1. An X-ray source, an X-ray spectroscope that disperses X-rays from the X-ray source, and a flexible portion that separates and extracts a part of the X-rays that are spectroscopically dispersed by the X-ray spectroscope and go straight. Hollow silica fiber, a manipulator for holding a sample and moving it relative to each other, a first detector for detecting the X-rays which have been separated by the X-ray spectroscope and are straight ahead and reflected by the sample, A second detector that detects X-rays that are separated by an X-ray spectroscope and bent by the hollow quartz fiber and transmitted through the sample; an X-ray source, an X-ray spectroscope, a hollow quartz fiber, a sample, and a manipulator. An X-ray evaluation apparatus comprising a vacuum chamber containing a first detector and a second detector. 2. The X-ray evaluation apparatus according to claim 1, wherein the X-ray spectroscope is a monochromator that interlocks by arranging channel-cut crystals in (+, +) arrangement.