JP3448111B2 - X-ray evaluation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is suitable for continuous "in-situ" observation of a high-resolution three-dimensional image of a thin film sample surface while forming a film in a high vacuum. X-ray evaluation device.

[0002]

2. Description of the Related Art A holographic method without using a lens has been known as one of analysis means using a high-resolution three-dimensional image (for example, refer to the document "Application of X-ray laser to physical property analysis" ( Toyota Central R & D Review Vo
See l.25 No. 4 (December 1990))). The holography method is used for waves such as light, electron beams, ultrasonic waves, and X-rays, and is a method of utilizing the interference effect of two waves. What is important in this holographic method is wave coherency.

Here, since the X-ray laser has high transmittance and directivity, and also has coherency as a characteristic of the laser, it is considered to utilize the interference, and in fact, the X-ray laser was used. Holographic methods are being considered. For example, there is a Gabor type holography as introduced in the above-mentioned document. FIG. 5 shows an example of the arrangement, in which monochromatic light obtained by monochromatic radiating light is spread through the pinhole 1, and the intensity distribution due to interference between scattered light and non-scattered light by the object 2 is a hologram which is a two-dimensional recording medium. The recording is performed on the recording medium 3.

There is also Gabor-type holography using an X-ray laser source, which is also introduced in the above literature. FIG. 6 shows an example of the arrangement, in which X-rays emitted from the X-ray laser source 4 are reflected and spread by the multilayer mirror 5 made of Mo-Si, and X-rays scattered by the object 6 and non-scattered X-rays. The hologram is recorded on the film 7 by the interference with the.

The methods shown in FIGS. 5 and 6 are holographic recording the intensity distribution due to the interference between the X-rays directly reaching the recording media 3 and 7 and the X-rays scattered from the objects 2 and 6. There is something in common. That is, a point where monochromatic X-rays are used to cause interference, and X-rays from the same light source scattered by the objects 2 and 6 and non-scattering X-rays are obtained, and these are interfered with each other to make the recording medium 3 , 7 are common.

[0006]

However, in the case of the holography method shown in FIG. 5, a light source device for monochromatic radiating light, which is a powerful X-ray, is required to obtain coherent light. Further, in the case of the holography method shown in FIG. 6, the X-ray laser source 4 having Se: λ to 20 nm is used as the light source device. In any case, the light source device is large and large,
For example, it becomes an X-ray evaluation apparatus far from being easily available in a laboratory or the like.

[0007]

An X-ray evaluation according to claim 1
The device consists of an X-ray source that emits X-rays and a channel cut
The X-ray formed by the (+, +) arrangement of the dispersive crystal.
X-rays incident from the source are separated into two monochromatic X-rays.
The monochromator and the single
A pinhole that spreads colored X-rays by diffraction and this pin
Monochromatic X-rays radiated directly from the hole and its pinhole?
Spread on the surface of the thin film sample and scattered by irradiation on the surface of the thin film sample.
A two-dimensional image of light intensity due to interference with color X-rays is used as a hologram.
Two-dimensional detector for detecting by X-ray source, monochrome image
And a thin film sample and a spectroscopic chamber having a built-in
A vacuum chamber containing a two-dimensional detector and the spectroscopic analysis
Provided between the vacuum chamber and the vacuum chamber
And a connecting portion having a pinhole.

[0008] X-ray evaluation equipment according to claim 2 is the X-ray source that emits X-rays, the cut channel analyzing crystal (+, +) X incident from the X-ray source is formed by the arrangement multi <br/> layer film superposed and two monochromators to monochromatic X-rays spectrally line, the two materials having different refractive index that reflects X-rays incident from the monochromator alternately The mirror and this multilayer mirror are reflected and directly illuminated.
Thin film sample spread from monochromatic X-ray and its multilayer mirror
Interference with monochromatic X-rays scattered by being irradiated on the surface
A two-dimensional detector for detecting a two- dimensional image of light intensity as a hologram , and a vacuum chamber containing these X-ray source, monochromator, multilayer mirror, thin film sample and two-dimensional detector are provided.

[0009]

According to the X-ray evaluation apparatus of the first aspect,
In the state where the subsequent monochromatic X-rays are aligned in phase by the pinhole
Since it can be spread, scattered X-rays and direct X-rays on the sample surface
And can be made to interfere on the plane of the two-dimensional detector.

In the X-ray evaluation apparatus according to claim 2 ,
By separating the X-rays emitted from the X-ray source with two monochromators and then reflecting them with a multilayer mirror,
Monochromatic as soft X-ray. Therefore, as the X-ray source, an ordinary and simple laboratory-level white X-ray source such as a rotor target may be used. In addition, the spectrum in the monochromator and the multilayer film mirror by the channel-cut dispersive crystal
Since it undergoes a reflection process, a monochromatic X-ray having good parallelism and coherency can be obtained. The monochromatic X-rays after the spectroscopic analysis by the monochromator are reflected on the surface of the thin film sample being formed in the vacuum chamber and interfere with the X-rays reflected by the multilayer film.
The hologram is continuously recorded on the dimension detector. This allows in-situ observation of the film surface structure or the like during film formation on the thin film sample surface.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. First, a vacuum chamber 12 that communicates with the vacuum exhaust device 11 and has a high vacuum state inside is provided. The vacuum chamber 12 includes a spectroscopic chamber 13 and X
The radiation source 14 is connected. Here, a Be (beryllium) window or the like is usually provided at the connection portion between the spectroscopy chamber 13 and the X-ray source 14, but in the present embodiment, the Be window is not provided. However, the chamber for spectroscopy 1
It is also possible to provide another vacuum evacuation device for 3 to evacuate at high speed. In addition, a shutter may be provided at the connecting portion between the spectroscopic chamber 13 and the vacuum chamber 12 to maintain the original vacuum degree in the vacuum chamber 12. In addition, the spectroscopy chamber 13
Inside the monochromator 16 together with the slit 15 for X-ray
Is built in. The monochromator 16 is mainly composed of a channel-cut dispersive crystal as will be described later. A member having a pinhole 17 is provided at the connecting portion between the spectroscopic chamber 13 and the original vacuum chamber 12. This member is exchangeable so that the pinhole diameter can be changed.

In the vacuum chamber 12, a thin film sample 18 to be measured is held downward by a manipulator 19 which is rotatable and movable. Further, in the vacuum chamber 12, a two-dimensional detector 20 for detecting a two-dimensional image is provided at a position facing the pinhole 17. In addition, in this embodiment, in order to enable analysis during film formation, the evaporation source 21 is placed below the thin film sample 18.
The following film forming apparatus is provided. 22 is the shutter.

Here, each part will be described in detail. First, X
As the radiation source 14, a rotor target mainly used in a laboratory is mainly used. This is W (tungsten),
A white X-ray is obtained by irradiating a metal such as Mo (molybdenum) or Cu (copper) with an electron beam. The brightness of such a simple X-ray source 14 is 1/1000 to 1/10000.
Therefore, the X-ray passages are all vacuum. For this reason, the emission portion of the X-ray source 14 has a B thickness of about 200 μm.
e All channels are evacuated without windows.

The degree of vacuum in the vacuum chamber 12, the spectroscopic chamber 13, and the X-ray source 14 is a high vacuum of 10 ^-6 Torr or more, preferably an ultra-high vacuum of 10 ^-9 Torr or more.

In the monochromator 16 for spectroscopy, two channel-cut spectroscopic crystals 23, for example, ammonium dihydrogen phosphate (ADP (101)) crystals are arranged (+, +) as shown in FIG. It is designed to work together. The dispersive crystal is not limited to ADP (NH ₄ H ₂ PO ₄ ), but may be YB ₆₆ , EDDT (C ₆ H ₁₄ N ₂ O ₆ ), RET.
(C (CH ₂ OH) ₄ ), α-quartz (SiO ₂ ), InS
It may be b, Si, Ge or the like. Here, the monochromator 16 of the present embodiment is for separating soft X-rays having a wavelength of about 5 to 500 Å from white X-rays from the X-ray source 14, and obtains relatively long soft X-rays. Therefore, for example, as shown in FIG. 2, precision processing is performed to have a substantially U-shaped cross section.

By arranging the two channel-cutting dispersive crystals 23 (+, +) in this way, the white X-rays emitted from the X-ray source 14 are emitted by these two dispersive crystals 23 four times. By being reflected, it is split into monochromatic X-rays that are soft X-rays. More specifically, the monochromator 1
As a result of the white X-rays incident on one of the dispersive crystals 23 of No. 6 being reflected by the crystal plane, when 2dsin θ = λ is satisfied, only a single wavelength λ is reflected and is dispersed. By setting this single wavelength λ to a relatively long soft X-ray wavelength, the soft X-ray can be dispersed.
In particular, in the case of the (+, +) arrangement of the monochromator configuration as in this embodiment, it is possible to obtain soft X-rays which have no divergence of X-rays, good parallelism, and high coherency.

By the way, regarding the monochromator structure by channel cut having a substantially U-shaped cross section, the cut surfaces are not parallel to each other as shown in FIGS. 1 and 2, and, for example, as shown in FIG. The crystal plane may be cut off. According to this, high-order reflection can be eliminated.

Next, the pinhole 17 is the monochromator 1.
When the monochromatic X-rays (soft X-rays) dispersed by 6 are irradiated toward the surface (deposition surface) of the thin film sample 18, the monochromatic X-rays are spread by a diffraction action, The pinhole diameter is changed accordingly. As will be described later, in order to obtain a hologram on the two-dimensional detector 20, instead of the pinhole 17, a multilayer mirror 25 made of Mo-Si or the like is used to reflect monochromatic X-rays as shown in FIG. However, according to the pinhole 17, it is possible to obtain a hologram in which only the X-rays in phase with each other are spread and interfered with each other. That is, the X-rays reaching the surface of the thin film sample 18 and the X-rays traveling straight can be expanded without changing the phase.

The two-dimensional detector 20 is separated by the monochromator 16 and directly irradiated from the pinhole 17.
The two-dimensional image of the light intensity due to the interference between the X-rays and the X-rays that are emitted from the pinhole 17 and are irradiated to and scattered on the surface of the thin film sample 18 is detected or recorded as a hologram. is there. This two-dimensional detector 20
As the X-ray film, a so-called film called an X-ray film (particularly, a soft X-ray film) or an imaging plate is used. Alternatively, PSD (semiconductor position detection element)
It is also possible to use an assembly of a microchannel plate (MCP) and a micro-channel plate (MCP), specifically, for example, PIAS-TI manufactured by Hamamatsu Photonics Co., Ltd., and once recorded, output it as a hologram.

According to the present embodiment having such a configuration, the X-ray hologram of the object to be evaluated can be easily and simply obtained by using the X-ray source 14 of a normal laboratory scale. For example, an Au (gold) thin film is a chemically stable film without oxidation and the like, but a thin film up to about 50 Å has a striped structure and is not a continuous film. Therefore, if the Au thin film structure on the surface of the thin film sample 18 is observed as a three-dimensional hologram by using the X-ray evaluation apparatus as in the present embodiment, more three-dimensional structural information can be obtained. Further, it is possible to use a thin film material, such as ZnO, which easily has a columnar structure, to observe what kind of three-dimensional structure the three-dimensional structure grows as it grows by film formation. Furthermore, since the monochromatic X-rays after the spectroscopy are soft X-rays, their transparency can be utilized unlike other electron beams, so that instead of the thin film sample 18 during film formation, it is targeted at living things. Then, a hologram of the living thing can be obtained.

In the present invention, as shown in FIG. 4, the multilayer mirror 2 is replaced with the pinhole 17 described above.
5 may be provided so that the soft X-rays dispersed by the monochromator 16 are reflected toward the sample 18 side and the two-dimensional detector 20 side. The multi-layer film of the multi-layer film mirror 25 is formed by alternately stacking two kinds of materials having different refractive indexes, and a high reflectance can be obtained due to multiple interference at the boundary surface. For example, it may be formed as a combination of molybdenum / silicon as shown in the above-mentioned documents.

[0022]

According to X-ray evaluation apparatus of the present invention, as the X-ray source can be used a conventional simple scale X-ray source of a laboratory level, such as the rotor target at any time easily and conveniently It is possible to obtain a hologram relating to the surface structure of the thin film sample, and further it is possible to observe in situ the film surface texture during film formation on the thin film sample surface.

In particular, instead of the multi-layer film mirror, a pinhole is provided between the thin film sample and the monochromator so that the monochromatic X-rays after the spectroscopy are spread by the pinhole in the phase aligned state. Direct X with scattered X-rays on the surface
The line can be made to interfere on the surface of the two-dimensional detector, and a hologram with higher resolution can be obtained.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing one monochromator.

FIG. 3 is an arrangement diagram showing a modified example of a monochromator.

FIG. 4 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 5 is a layout view of a Gabor holography showing a conventional example.

FIG. 6 is a layout diagram of a Gabor holography using an X-ray laser source showing a different conventional example.

[Explanation of symbols]

12 vacuum chamber 14 X-ray source 16 Monochromator 17 pinholes 18 Thin film sample 20 Two-dimensional detector 23 Spectroscopic crystal 25 Multilayer mirror

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 23/00-23/227 G03H 5/00

Claims (2)

(57) [Claims] 1. An X-ray source that emits X-rays and a channel cover.
Formed by the (+, +) arrangement of the dispersed crystal
The X-rays incident from the X-ray source are separated into monochromatic X-rays.
Two monochromators and this monochromator
Pinholes that spread the isolated monochromatic X-rays by diffraction,
X-rays directly radiated from the pinhole of
Scattered by radiating to the surface of the thin film sample from the mirror
A two-dimensional image of the light intensity due to the interference with the monochromatic X-ray
Two-dimensional detector for detecting as a ram, the X-ray source and mono
Spectrometer chamber with built-in chromometer, and thin film test
A vacuum chamber containing a material and the two-dimensional detector,
Provided between the spectroscopic chamber and the vacuum chamber
And a connecting portion having the pinhole.
A characteristic X-ray evaluation apparatus. 2. An X-ray source which emits an X-ray and a (+, +) arrangement of a channel-cutting dispersive crystal. The X-ray incident from the X-ray source is separated into monochromatic X-rays . A mixture of two monochromators and two types of materials with different refractive indices that reflect the X-rays incident from this monochromator.
And the multi-layer film mirror was overlapped each other, the multi-layer film mirror
Is it a monochromatic X-ray that is reflected and directly irradiated and its multilayer mirror?
Spread on the surface of the thin film sample and scattered by irradiation on the surface of the thin film sample.
A two-dimensional image of light intensity due to interference with color X-rays is used as a hologram.
And a two-dimensional detector to detect, X-ray evaluation apparatus characterized by comprising a vacuum chamber, a that incorporates these X-ray source and the monochromator and the multilayer mirror and the thin film sample and the two-dimensional detector .