JPH0543080B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a scanning X-ray microscope.

PRIOR ART Hitherto, there is no suitable lens for bending X-rays. Therefore, it does not exist in an X-ray microscope, which has the same principle as an optical microscope. In order to observe internal defects in highly perfect crystals, X-ray topography plays the role of a microscope, but it is extremely rare.

In addition, the X-rays generated from the point-shaped X-ray generator,
The X-rays are exposed to X-rays by a thin plate-shaped sample, and a magnified transmission image (shadow picture) is taken on a film behind it, or a thin living body piece is pasted on the film, exposed to X-rays, the sample is removed, and after development, Radiography, which involves observation using an optical microscope, is also known. However, in all of these methods, the shape of the sample that can be observed is extremely limited and is not general.

Purpose of the Invention The present invention was made to solve the problems of conventional X-ray microscopes. An object of the present invention is to provide a scanning X-ray microscope capable of observing and inspecting.

Structure of the Invention A sample stage has a function of sequentially moving a sample a fixed distance in a two-dimensional plane perpendicular to the direction of incidence of X-rays or sequentially rotating a single base angle; An X-ray conduit through which the rays enter, a measuring instrument with an X-ray energy analysis function that measures the energy and number of photons of secondary X-rays generated from a minute area of the sample, and these measurement values and sample position parameters or rotation angles. Extracts the distribution of the number of X-ray photons at a specified energy as an image using the sample position parameter or rotation angle parameter from the storage device that stores parameters and the measurement values obtained by sequentially moving or rotating the sample. do,
It is characterized by having an image processing device that forms a scattered X-ray image, a diffraction X-ray image, a transmitted X-ray image, a fluorescent X-ray image, or a tomographic image thereof.

Note that if a sample position is selected where the measurement point, that is, the intersection of the direction of incident X-rays and the direction of the X-ray detector is inside the surface of the sample, a scanning X-ray tomographic microscope is obtained.

Part of the principle of the invention corresponds to a scanning electron microscope. In the history of the development of electron microscopes, transmission type and scanning type have developed in parallel. The former is an image magnification method similar to an optical microscope that uses an electron lens that takes advantage of the fact that electron beams are bent in a magnetic field. On the other hand, the latter method makes the electron beam as thin as possible, measures the intensity of various interactions occurring in the sample (e.g., secondary electrons, fluorescent X-rays, backscattered electrons, etc.), and synchronizes the movement of the electron beam. and display it on a cathode ray tube as an image. Therefore, the resolution of the former image is determined by the aberration of the electron lens, and the latter is determined by the thickness of the electron beam.

In the scanning X-ray microscope of the present invention, an X-ray conduit is used to create a fine bundle of X-rays, which is irradiated onto a minute part of the sample, and scattering, diffraction, transmission, and secondary X-ray intensity are measured. Display their intensity in synchronization with movement to create a magnified image. Therefore, in that the measurement using a thin beam bundle and the movement of the measurement unit are synchronized, it is the same as the image magnification mechanism of a scanning electron microscope, and the limit of resolution depends on the thickness of the thin X-ray beam. The same applies to the points that can be determined accordingly.

However, in the case of the present invention, the scanning mechanism moves the sample minutely, whereas in the case of a scanning electron microscope, it waves the incident electron beam. The present invention applies the outline of the imaging and image magnification mechanism used in scanning electron microscopes to X-rays, and also realizes a narrow beam of X-rays using an X-ray conduit that makes this application possible. be.

An example of an embodiment of the scanning X-ray microscope of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view including a partially sectional view, and FIG. 2 is a side view including a partially sectional view. In the figure, 1 is a pulse generator and high voltage generator for generating pulsed or continuous X-rays, 2 is a computer for measurement, sample movement, and image processing, and 3 is a computer for sample movement and detector position control. 4 is a pulse height analyzer for a solid-state detector; 5 is a pulsed or continuous micro-focus high-intensity X-ray generator; 6 is an entrance-side X-ray conduit attitude controller; 7 is an entrance-side X-ray conduit; 8 is 9 is a sample X-direction (horizontal, perpendicular to the X-ray direction) micro-movement mechanism; 10 is a sample rotation mechanism in the horizontal plane; 11 is a sample Z-direction (height) micro-movement mechanism; 12 is a fixed 13 is an X-ray detector (solid state detector/SSD) 14 is a preamplifier for the X-ray detector, 15 is a receiving side X-ray conduit attitude control mechanism, 16 is an X-ray detector horizontal rotation mechanism, 17 is a sample tilt control mechanism (Parallel to the direction of the X-rays) 18 represents the same (perpendicular to the direction of the X-rays).

The microfocus X-ray generator 5 has a metal anticathode.
This device is similar to a normal X-ray generator that collides with electron beams accelerated to 60 to 300 kV. In order to obtain finely focused, high-intensity X-rays, the electron beam is focused onto the anticathode using an electronic coil 18, for example, as shown in the figure. It is even more efficient if it is of a type that can receive a pulsed power supply from the pulse generator 1 and generate pulsed X-rays. However, the generation of pulsed X-rays is synchronized with the sample position and movement, the movement period is a rest period, and X-rays are generated only during measurement. The generation of pulsed X-rays and the movement of the sample are synchronized using a control computer 2.

The incident side X-ray conduit 7 is used to efficiently guide the high-intensity X-rays generated at the minute point to one point on the sample (the center of rotation of the sample and the measuring device). In the figure, it is shown as a rotating elliptical X-ray conduit. Instead of this, long cone
It may be a ray conduit, a cylindrical X-ray conduit, a parabolic X-ray conduit, or a hollow tube similar thereto.

Examples of X-ray conduits include:

(1) A hollow tube whose inner wall surface is shaped like a spheroid with both ends cut off, with two focal points: the point where X-rays are generated by electron beam irradiation and a fixed measurement point; A hollow tube that satisfies the condition that the angle of incidence of X-rays emitted from one focal point on the inner wall surface does not exceed 10 milliradians as a relationship between the distance and the maximum diameter of the hollow tube, (2) twice the critical angle for total reflection of X-rays. A hollow tube whose inner wall surface has the shape of a cone with both ends cut off or a cylindrical shape with an apex angle that does not exceed (3) y ² = 4fx (here, f is expressed as f = (r・θ)/2) y, r is the aperture at the tip of the conduit, and θ is the critical angle of total reflection of X-rays.
It is a hollow thin tube whose inner wall surface is shaped like the cut off tip of a paraboloid of revolution rotated around its axis, and whose inner wall surface is smooth enough to cause total X-ray reflection.

The orientation of the incident side X-ray conduit 7 is adjusted using the incident side X-ray conduit attitude controller 6.

The centers of rotation of the sample horizontal plane rotation mechanism 10 and the X-ray detector horizontal plane rotation mechanism 16 are measurement points, and the position to be measured on or in the sample is minutely moved in the X direction of the sample around this rotation center. The mechanism 9, the sample Z-direction minute movement mechanism 11, and the sample tilt control mechanisms 17 and 18 are used to align the samples. In order to measure the X-rays generated or transmitted from the measurement point at any angle depending on the purpose, an X-ray detector horizontal rotation mechanism 16 is used.

FIG. 1 shows an arrangement for measuring scattered, diffraction, or secondary X-rays, and the detector is located at approximately 120° relative to the zero incident direction of the X-rays. Figure 2 shows the arrangement for measuring the amount of transmitted X-rays, with the detector at 0°.

The intensity of X-rays scattered, diffracted, or generated from a minute area decreases with distance due to their divergence.

In order to prevent this, in this device, the receiving side X-ray conduit 8
Use. In FIGS. 1 and 2, a long paraboloid of revolution X-ray tube with an extremely small focus is shown. Alternatively, it may be of a rotating oblong shape, a long conical shape, or a cylindrical shape.

As the X-ray detector 13, a scattered X-ray image, a diffraction
In order to observe various X-ray images such as ray images, secondary X-ray (fluorescent X-ray) images, and transmission X-ray images depending on the purpose, a solid-state detector (e.g. SSD) with X-ray energy resolution is required. use However, a scintillation counter can be used for detecting defects in metals or sintered ceramics that do not require much precision.

The measured value at one point on the sample and the position of the measurement point are stored in the computer, and the sample position is transferred to the sample X direction fine movement mechanism 9 and the sample Z direction fine movement mechanism 11.
Measurement is carried out by moving using the , and this operation is repeated one after another to measure each point in the entire area within the XZ plane.
Computer 2 stores the position and measured value of each measurement point, controls the movement of the sample in the XZ plane, and based on the memory, sequentially moves or rotates the sample over the entire preset area for measurement. The distribution of the number of X-ray photons of the specified energy is extracted as an image from the measured values obtained by
A diffraction X-ray image, a transmission X-ray image, a fluorescence X-ray image, or their tomographic image is formed on a cathode ray tube or
Display on an XY plotter or as a numerical matrix.

Effects of the Invention According to the scanning X-ray microscope of the present invention, conventional X-ray
An excellent effect can be achieved in that it is possible to observe and inspect images caused by X-ray scattering, diffraction, absorption, secondary X-ray emission, etc. of metals and ceramics, which was impossible with a ray microscope.

[Brief explanation of the drawing]

The drawings show an embodiment of the scanning X-ray microscope of the present invention, with FIG. 1 being a plan view and FIG. 2 being a side view. 1: Pulse generator and high voltage generator, 2: Computer, 3: Pulse motor controller for position control, 4: Wave height analyzer for solid state detector, 5: Microfocus high intensity X-ray generator, 6: Incident side X Ray conduit attitude controller, 7: Incident side X-ray conduit, 8: Light receiving side X-ray conduit, 9: Sample minute movement mechanism, 10: Sample horizontal rotation mechanism, 11: Sample minute movement mechanism, 12: Surface plate, 13 : X-ray detector, 14: X-ray detector preamplifier, 15: X-ray conduit attitude control mechanism, 16: X
Ray detector horizontal plane rotation mechanism, 17: Sample tilt control mechanism (parallel to the direction of X-rays), 18: Sample tilt control mechanism (perpendicular to the direction of X-rays).

Claims (1)

[Claims] 1. A sample stage that has the function of sequentially moving a sample a certain distance or sequentially rotating a certain angle in a two-dimensional plane perpendicular to the incident direction of X-rays, and An X-ray conduit that injects high-intensity X-rays, a measuring instrument with an X-ray energy analysis function that measures the energy and number of photons of secondary X-rays generated from a microscopic region of a sample, and these measured values and sample position parameters. Alternatively, the distribution of the number of X-ray photons at a specified energy can be calculated using a storage device that stores the rotation angle parameters and the measurement values obtained by sequentially moving or rotating the sample. A scanning X-ray comprising an image processing device that extracts an image and forms a scattered X-ray image, a diffraction X-ray image, a transmitted X-ray image, a fluorescent X-ray image, or a tomographic image thereof. microscope. 2. The X-ray conduit is a hollow tube whose inner wall shape is a shape obtained by cutting both ends of a spheroid with two focal points: the point of generation of X-rays by electron beam irradiation and a fixed measurement point, and the X-ray tube has two focal points: The relationship between the distance between the two focal points and the maximum diameter of the hollow tube satisfies the condition that the angle of incidence of X-rays emitted from one focal point on the inner wall surface does not exceed 10 milliradians, and the inner wall surface is smooth enough to cause total X-ray reflection. 2. The scanning X-ray microscope according to claim 1, which is a hollow thin tube constituted by a surface. 3. The X-ray conduit is a hollow tube whose inner wall has the shape of a cone with both ends cut off or a cylindrical shape with an apex angle not exceeding twice the critical angle of total reflection of X-rays, and whose inner wall surface is 2. The scanning X-ray microscope according to claim 1, which is a hollow tube having a smooth surface capable of causing total linear reflection. 4 The X-ray conduit is y ² = 4fx (where f is f = (r・
θ)/2, r is the diameter of the tip of the conduit,
θ is the critical angle of total reflection of X-rays) is a hollow tube whose inner wall surface has a shape obtained by cutting off the tip of a paraboloid of revolution rotated around the y-axis, and whose inner wall surface is 2. The scanning X-ray microscope according to claim 1, wherein the tube is a hollow tube having a smooth surface capable of causing total reflection of X-rays.