JPH07174900A - X-ray optical element, x-ray optical device, and aligning method - Google Patents

Abstract

PURPOSE:To simply adjust the optical axis of X-ray optical elements in a short time. CONSTITUTION:A plurality of X-ray optical elements 2-6 are arranged in an X-ray optical device, with the optical axis AX aligned in common. Optical axis adjusting alignment marks 11 set with the relative positional relations with the optical axis AX of the X-ray optical elements 2-6 in advance are provided on the X-ray optical elements 2-6 respectively. Positions of the X-ray optical elements 2-6 are adjusted by a driving mechanism 16 so that the respective alignment marks 11 of the X-ray optical elements 2-6 are located on the same straight line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray optical element such as an X-ray zone plate used in an X-ray optical apparatus such as an X-ray microscope, and an alignment method thereof.

[0002]

2. Description of the Related Art In recent years, X-ray optical devices, such as X-ray microscopes and X-ray reduction exposure devices, have been proposed which use X-rays having a shorter wavelength than visible light. As an example, the X-ray microscope is a microscope that uses short-wavelength (2-4 nm) X-rays as observation light. Conventionally, there are mainly optical microscopes and electron microscopes as microscopes for observing the inside of cells which are indispensable for biological observation. An optical microscope can observe living organs, but its resolution is limited to 200 nm because it uses visible light. On the other hand, the electron microscope has a much higher resolution than the optical microscope because it uses an electron beam with a short wavelength, but since the sample has to be put in a vacuum, the living organisms are kept alive. It's difficult to observe. Therefore, an X-ray microscope that covers an area that cannot be observed by both the optical microscope and the electron microscope has been developed.

Since an X-ray microscope uses short-wavelength X-rays, the resolution is 5 nm, which is finer than the limit of an optical microscope, and at the present time, the X-ray transmittance of a sample is imaged. It is possible to observe with a contrast different from that of the optical microscope used. In addition, since X-rays having a wavelength used in an X-ray microscope penetrate water, it is possible to observe living organs of living organisms and observe dynamic movements of living organisms.

FIG. 12 is a schematic diagram showing an optical system of a conventional X-ray microscope. In this figure, 1 is an X-ray source whose position is indicated by a point, 2 is a filter, 3 is a condenser zone plate, 4 is a diaphragm, 5 is a holder for holding a sample (sample) not shown, 6 is an objective zone plate, 7 is an X-ray detector. These X-ray source 1, filter 2, etc.
It is arranged in a vacuum container (not shown) in order to prevent X-rays from being attenuated by air.

Conventionally, the optical axis adjustment of an X-ray optical element such as the filter 2 is performed by roughly adjusting the optical axis by using a frame for attaching the X-ray optical element when the X-ray optical element is placed in a vacuum container. The steps of irradiating X-rays from the X-ray source 1 to check the image forming position after drawing a vacuum in the container and the step of finely adjusting the position of the X-ray optical element by opening the inside of the vacuum container to the atmosphere. It went by repeating.

[0006]

However, in the conventional X-ray microscope, since the X-ray optical element is actually irradiated to adjust the optical axis of the X-ray optical element, a vacuum is drawn in the vacuum container. The process of opening to the atmosphere had to be repeated, and adjustment of the optical axis took a very long time. Since the optical axis adjusting step is required every time the sample or the optical element is replaced, there is a great demand for performing the optical axis adjusting step quickly.
In addition, the size of the sample observed with an X-ray microscope is several hundred μ.
Since it is as small as about m, it is difficult to finely adjust the optical axis. Furthermore, since X-rays are used for fine adjustment of the optical axis, the sample may be irradiated with X-rays even during this optical axis adjustment work, and the sample may be exposed to the X-rays for a long time. If the sample is irradiated with X-rays for a long time, the sample may be killed, and thus it may not be possible to observe the organs of living organisms with a conventional X-ray microscope.

It is possible to irradiate the X-ray optical element with visible light instead of X-rays to adjust the optical axis. However, in the case of a reflecting mirror, the X-ray propagation path and the visible light propagation path are common. However, in the zone plate, since the imaging action is realized by using diffraction or the like, if the wavelength is different, the propagation path is also different and the optical axis cannot be adjusted accurately.

It is an object of the present invention to provide an X-ray optical element, an X-ray optical device and an alignment method which can easily adjust the optical axis of the X-ray optical element in a short time.

[0009]

To explain the present invention by associating it with FIG. 1 showing an embodiment, in the invention of claim 1, the X-ray optical elements 2 to 6 have a relative positional relationship with the optical axis AX in advance. The above-described object is achieved by providing the predetermined alignment mark 11 for adjusting the optical axis.

Further, the invention of claim 2 is applied to an X-ray optical apparatus in which a plurality of X-ray optical elements 2 to 6 are arranged so that their optical axes AX are in common, and the above-mentioned object is X-ray. The optical axis adjusting alignment marks 11 provided on the linear optical elements 2 to 6 and having a predetermined relative positional relationship with the optical axis AX are used. This is achieved by providing position adjusting means 16 for adjusting the positions of the X-ray optical elements 2 to 6 so that they are located on a straight line.

Furthermore, in the invention of claim 3, the X-ray optical elements 2 to 6 are arranged so that the optical axes AX are arranged in common.
The present invention is applied to an alignment method for adjusting the positions of the X-ray optical elements 2 to 6, and the above-mentioned object is applied.
X-ray optical elements 2 to 6 such that the alignment marks 11 provided on each of the X-ray optical elements 2 to 6 are positioned on the same straight line so that the relative positional relationship with each of the optical axes AX of the X-ray optical elements is the same. It is achieved by adjusting the position of.

[0012]

The alignment mark 11 for adjusting the optical axis is provided at a position where the relative positional relationship with the optical axis AX of each of the X-ray optical elements 2 to 6 is set in advance. By adjusting the positions of the respective X-ray optical elements 2 to 6 so that they are positioned on the line, the X-ray optical elements 2 to
The six optical axes AX can be made common.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0014]

1 is a diagram showing an embodiment of an X-ray microscope to which an X-ray optical apparatus according to the present invention is applied. Also in the X-ray microscope of the present embodiment, the X-ray source 1, the filter 2, the condenser zone plate 3, the diaphragm 4, the sample holder 5, the objective zone plate 6 and the X-ray CCD 7 as the X-ray detector are used as in the conventional case. I have it.

2 to 5 are plan views showing an X-ray optical element used in the X-ray microscope of this embodiment. FIG. 2 is an objective zone plate, FIG. 3 is a condenser zone plate, and FIG. 4 is a sample holder. FIG. 5 shows a diaphragm. The zone plates 3 and 6, the sample holder 5, and the diaphragm 4 (and the filter 2 (not shown)) are supported by a silicon wafer 10, which is a supporting substrate. In this embodiment,
The planar shape of the silicon wafer 10 is formed into a substantially square shape having the same shape, and each optical element is supported by the silicon wafer 10 so that the optical axis of each optical element is located at the center of the silicon wafer 10.

On the silicon wafer 10 supporting each X-ray optical element, windows 11 are formed as alignment marks at the four corners which are locations that do not affect the propagation of X-rays. The windows 11 of each silicon wafer 10 are formed in the same shape, and are formed in such positions that the relative positional relationship with the optical axis of the optical element supported by the silicon wafer 10 is the same in each silicon wafer 10. ing.

In this embodiment, the window 11 formed in the silicon wafer 10 is a through hole having a substantially square plan shape. Although the method of manufacturing the window 11 is arbitrary, since the silicon wafer 10 has a plane orientation, if the through holes are formed in the silicon wafer 10 by anisotropic etching, the four corners of the window 11 can be made substantially right angles, and A window 11 having smooth sides can be formed. However, when the silicon wafer 10 is etched by anisotropic etching, the shape of the window 11 becomes tapered as shown in FIG. 9, so that the length of one side of the thinnest portion of the window 11 (indicated by d in the figure). May be formed so as to be common to the windows 11 of each silicon wafer 10.

As an example, when each side of the silicon wafer 10 is 10 mm and the diameter of the condenser zone plate 3 of the largest optical element is 100 μm, the window 11 having a side length of 100 μm is located 1 mm from the end. Is formed. The length of one side of the window 11 is the detector (CC
D) It is determined in consideration of the size of the light receiving surface 18a of 18 and the influence of diffraction by the window 11.

Each silicon wafer 10 is shown in FIGS. 6 (a) and 6 (b).
As shown in FIG. 3, the support frame 12 is arranged between the two support frames 12, and is clamped by a fastening means such as a bolt 13 so as to be fixed in a vacuum container (not shown). Therefore, the window 11 described above is formed by removing the portion supported by the support frame 12. In this embodiment, as shown in FIG. 1, the silicon wafers 10 are arranged parallel to each other with a predetermined interval required for optical design, and the optical axes AX of the optical elements are the same. It is arranged so as to be located on the line.

In the vacuum container, as shown in FIG. 7, an inclination drive device 14 for inclining the support frame 12 and an inclination drive device 14 are respectively driven by a minute distance in the Y-axis direction and the Z-axis direction in the drawing. A YZ stage 15 is provided, and the tilt drive device 14 and the YZ stage 15 allow the silicon wafer 10 and eventually each X-ray optical element to move on the YZ plane in the vacuum container. In addition,
In FIG. 1, the tilt drive device 14 and the YZ stage 15 are generally illustrated as a drive mechanism 16 only in outline. The drive amount of the drive mechanism 16 can be controlled from outside the vacuum container by a control device (not shown). As the actuator that drives the support frame 12 in the drive mechanism 16, for example, a piezoelectric element or the like is used.

In the vacuum container, the silicon wafer 1
Four light sources 17 (only two of which are shown in FIG. 1) are arranged to emit the light beam BM parallel to the optical axis AX toward the four windows 11 at the four corners of 0. In this embodiment, a He—Ne laser is used as the light source 17, and the beam diameter of the laser beam BM emitted from the light source 17 is equal to the length of one side of the window 11. Further, in the vacuum container, the silicon wafer 10 is sandwiched between the light source 17 and the opposite side.
Four photodetectors 18 (only two are shown in FIG. 1) are arranged to detect the light from the light source 17. In this embodiment, a CCD is used as the photodetector 18, which is shown in FIG.
As shown in FIG.
The light beam BM from 7 arrives.

Next, an example of an optical axis adjusting method (alignment method) of each X-ray optical element by the X-ray microscope of this embodiment will be described. First, one X-ray optical element (and the silicon wafer 10 supporting it) is held by a support frame 12 and fixed in a vacuum container by a bolt 13. At this time, rough alignment is performed using the relative position between the support frame 12 and the silicon wafer 10. Next, the light beam BM is emitted from the light source 17, and the amount of received light is detected by the photodetector 18. Then, the drive mechanism 16 adjusts the three-dimensional position of the X-ray optical element (and the silicon wafer 10 supporting the same) so that the amount of light received by the photodetector 18 is maximized. As a result, the X-ray optical element is changed to the one shown in FIGS.
Can be located on the YZ plane and can be positioned at a specific position on the YZ plane, and its optical axis is a predetermined straight line (this is the optical axis AX of the entire X-ray microscope).
Can be located on top. Hereinafter, if the same work is performed for each X-ray optical element, the optical axes of all the X-ray optical elements can be positioned on the same straight line AX, and the optical axis of each X-ray optical element can be adjusted. You can

Therefore, according to this embodiment, the optical axis adjustment work of each X-ray optical element can be performed without irradiating the X-rays to finely adjust the optical axis, and the optical axis can be easily adjusted in a short time. Axis adjustment can be performed. Moreover, since it is not necessary to irradiate the sample with X-rays, it becomes easy to observe the biological sample alive.

Further, in this embodiment, the silicon wafer 1
The four corners of 0 are etched to form windows 11 as alignment marks. Usually, X-ray optical elements such as zone plates, diaphragms and filters are manufactured by applying the semiconductor manufacturing process, so that the window 11 can be formed at the same time when the X-ray optical elements are manufactured, and the accuracy of dimensions and the like is good, Moreover, the relative positional relationship with the optical axis of each X-ray optical element can be made highly accurate.

In the correspondence between the embodiment described above and the claims, the filter 2, the condenser zone plate 3, the diaphragm 4, the sample holder 5 and the objective zone plate 6 are X-ray optical elements, and the window 11 is an alignment mark. The drive mechanism 16 constitutes position adjusting means.

The details of the X-ray optical element, the X-ray optical apparatus and the alignment method of the present invention are not limited to the one embodiment described above, and various modifications are possible. As an example, although the window (through hole) is used as the alignment mark in the embodiment, the alignment mark is not limited to this. For example, when the X-ray optical element is supported by transparent glass, FIG. As shown, cross-shaped alignment marks 21 are printed on the four corners of the glass plate 20, and the positions of the crosses may be adjusted by observing the crosses with a collimator or the like so that the crosses overlap. At this time, if the size of each alignment mark 21 is changed as shown in FIG. 11, it is possible to easily and reliably detect which X-ray optical element is displaced. Alternatively, in the case of observing with infrared light, since silicon has a high infrared light transmittance, the alignment mark as shown in FIG. 11 may be formed without forming a through hole.

Further, as shown in FIG. 10, the light BM from the light source 17 is directed to the silicon wafer 10 side by the half mirror 22, and the light BM is reciprocated by the reflecting mirror 23 arranged on the opposite side to cause the photodetector 18 to move. It may be detected. The number of alignment marks to be provided on each X-ray optical element is not limited to four as in the embodiment, and the optical axis adjustment including the inclination of the X-ray optical element is possible if there is at least three alignment marks. Further, the drive mechanism of the X-ray optical element is not limited to that of the embodiment, and a fine adjustment mechanism such as a micrometer can be used.

[0028]

As described in detail above, according to the present invention, each X-ray optical element of each X-ray optical element is arranged so that the alignment marks whose relative positional relationship with the optical axis is predetermined are arranged on the same straight line. Since the optical axis adjustment work is performed by adjusting the position, the optical axis can be adjusted without irradiating each X-ray optical element with X-rays as in the conventional case, and the X-ray optics can be easily and quickly performed. The optical axis adjustment work of the element can be performed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an X-ray microscope to which an X-ray optical element according to an embodiment of the present invention is applied.

FIG. 2 is a plan view showing an objective zone plate used in one embodiment.

FIG. 3 is a plan view showing a condenser zone plate used in one embodiment.

FIG. 4 is a plan view showing a sample holder used in one embodiment.

FIG. 5 is a plan view showing a diaphragm used in one embodiment.

FIG. 6A is a plan view showing a support frame, and FIG. 6B is a side view.

FIG. 7 is a side view showing a drive mechanism.

FIG. 8 is a plan view showing a light receiving surface of a photodetector.

FIG. 9 is a sectional view of a window.

FIG. 10 is a schematic view showing another example of an X-ray microscope to which the X-ray optical element according to the embodiment of the present invention is applied.

FIG. 11 is a plan view showing an X-ray optical element that is another embodiment of the present invention.

FIG. 12 is a schematic view showing an example of a conventional X-ray microscope.

[Explanation of symbols]

 AX optical axis 1 X-ray source 2 Filter 3 Condenser zone plate 4 Aperture 5 Sample holder 6 Objective zone plate 7 X-ray detector 10 Silicon wafer 11 Window 12 Support frame 14 Tilt drive 15 YZ stage 16 Drive mechanism 17 Light source 18 Optical detection vessel

Claims (3)

[Claims] 1. An X-ray optical element comprising an optical axis adjusting alignment mark having a predetermined relative positional relationship with the optical axis. 2. An X-ray optical device in which a plurality of X-ray optical elements are arranged such that their optical axes are common, and the X-ray optical elements are provided with a relative positional relationship with the optical axis set in advance. The alignment mark for adjusting the optical axis, and position adjusting means for adjusting the position of the X-ray optical element so that the respective alignment marks of the X-ray optical element are located on the same straight line. X-ray optical device. 3. An alignment method for adjusting the positions of the X-ray optical elements so that the optical axes of the plurality of X-ray optical elements are arranged in common. An alignment method, wherein the position of the X-ray optical element is adjusted such that the alignment marks provided on each of the X-ray optical elements are positioned on the same straight line so that the positional relationship is the same.