JPH06300899A - Soft x-ray microscope - Google Patents

Abstract

PURPOSE:To provide a soft X-ray microscope of simple structure which can select observation part and focus under visible light before soft X-ray irradiation and observe specimen with high resolution of 0.01 to 0.04mum without damaging the specimen. CONSTITUTION:To an X-ray microscope having a soft X-ray source, pulse laser 1 for irradiating a specimen 7 through a condenser lens 5, a Schwarzschild type objective lens 9 as a soft X-ray object lens for magnifying the image of the specimen by soft X-ray, a phosphor 10 for converting the magnified image to visible light, an objective lens 12 of an optical microscope for remagnifying the image converted to visible light, and an image intensifier 13 as a photographing element sensible to visible light for detecting the remagnified image, a visible light source 21 for casting visible light to the specimen 7 is provided. And by catching the magnified image of the specimen by the visible light with the soft X-ray objective lens, observation with visible light is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray microscope, and more particularly to a high resolution soft X-ray microscope apparatus suitable for living body observation, semiconductor inspection and the like.

[0002]

2. Description of the Related Art Since the resolution of an ordinary optical microscope using visible light is approximately 0.2 μm, an electron microscope is used for observation requiring higher resolution. However, in order to observe a living body or the like with an electron microscope, pretreatment such as dehydration and fixation is required, and there is a restriction that the observation must be performed in a vacuum. Therefore, the development of a soft X-ray microscope which realizes high resolution and observation in air by using light in the soft X-ray region has been advanced. Among them, the one called “water window” for the purpose of observing the living body 23
Development of a soft X-ray microscope using a wavelength region of up to 43Å is underway.

The soft X-ray microscope includes a soft X-ray light source, a condenser lens that collects the soft X-rays emitted from the soft X-ray light source on a sample, and soft X-rays or fluorescence reflected or transmitted from the sample. Is composed of an objective lens for enlarging and forming an image, a detector for detecting the formed image, and the like, and the detected image is displayed on a CRT or the like. In the soft X-ray region, the refractive index of any substance is a value close to 1, refraction or reflection hardly occurs, and absorption is large. Therefore, as the objective lens, an oblique incidence optical system using a total reflection phenomenon, a direct incidence reflection optical system using a multilayer film, or a zone plate optical system using diffraction is used.

Generally, in an imaging optical system, the resolution (resolution) δ is given by δ = 0.61λ / NA (where λ is the wavelength, NA is the numerical aperture of the objective lens). Here, assuming that the wavelength to be used is 40 Å, in the oblique incidence optical system, the NA is estimated to be about 0.06 at maximum due to the relationship of the total reflection angle, so the resolution δ is about 400 Å from the above formula, that is, about 0.04 μm. Become. Further, in a direct-incidence reflection optical system using only spherical surfaces, NA is 0.
It is thought that about 25 is the limit, and the resolution is about 100.
Å, that is, 0.01 μm. Therefore, the resolution of the soft X-ray microscope is about 0.01 to 0.04 μm, and it is expected that this resolution will be further improved by future technical improvement. When considering a soft X-ray microscope with a size that is easy to use, it is necessary that the objective lens has a magnification of about 100 and the resolution of the detector is several μm or less.

Generally, a solid-state image pickup device such as a microchannel plate (MCP) or a CCD is used as a soft X-ray detector. In that case, the distance between each pixel is 10 or less.
Since it is more than μm, the resolution is insufficient. Therefore, a method is used in which the image is re-enlarged by some method and then detected by the MCP or CCD. As a method for re-enlarging an image, a method using an image-type detector for electron-optically enlarging an image or a method for enlarging an enlarged image by an objective lens by a magnifying lens has been proposed.

The above-mentioned method of electronically enlarging the image is performed as shown in FIG. That is, the electrons emitted from the electron gun 40 are focused on the target 42 by the condenser electron lens 41, and characteristic X-rays (in the case of a soft X-ray microscope, soft X-rays are used among the generated X-rays) are generated. Then, the sample 43 is irradiated. The X-ray transmitted through the sample 43 is converted by the Walter objective lens 44 into the photoelectric conversion surface 4 such as CaI.
The image is magnified and projected on 5, and the photoelectric conversion surface 45 once converts the X-rays into electrons. The electrons are electro-optically re-enlarged by the electronic lens 46, and an enlarged image by the electrons is formed on the MCP 47. The image amplified by the MCP 47 is used as a fluorescent screen 48.
It is converted into visible light by and is detected by the CCD camera 49. The above system is kept in vacuum by the chamber 50.

A method for further enlarging the magnified image with the above soft X-rays is performed as shown in FIG. That is, the sample 51 irradiated with soft X-rays is magnified by the grazing incidence type objective lens (Walter type is used in this example) 52 to obtain a first image 53, and the first image 53 is further grazing incidence type. Re-magnification by a reflector (using Walter type in this example) 54. Then, the image 55 by the re-enlarged soft X-ray is detected by the MCP or CCD 56.

By the way, in the above-mentioned method of enlarging an image electronically and optically, the apparatus becomes complicated, the aberration due to the electron lens becomes a problem, and the soft X transmitted without being converted by the photoelectric conversion surface.
There is a problem that the line directly enters the detector and adversely affects the image. Further, the above-described method of further enlarging the magnified image with the soft X-rays entails enlargement with the soft X-rays, resulting in a large light amount loss and an increase in the size of the apparatus.

In view of these problems, Japanese Patent Laid-Open No. 3-20
A microscope described in Japanese Patent Publication No. 0099 has been proposed. According to the conventional example described in this publication, after converting soft X-rays into visible light including ultraviolet rays by a phospher (a member such as a phosphor or a phosphor that converts soft X-rays into visible light), normal optical MCP after enlarging with the microscope objective lens
By adopting a configuration in which images are detected by a CCD or CCD,
A soft X-ray detector having a resolution of about 10 μm is used so that the microscope has a resolution of 0.01 μm.

[0010]

Since the energy of soft X-rays is high, irradiating the sample with soft X-rays for a long time causes a large damage to the sample, which is not preferable. However, in the above-mentioned conventional example, in order to obtain a high resolution of, for example, 0.01 μm, it is necessary to enlarge the total magnification to 2000 times or more, so the field of view becomes extremely narrow. It becomes difficult to explore the part of
It is difficult to search a desired part of the sample within the limited soft X-ray exposure time of the sample. In addition, since it is necessary to shorten the time required for focusing as much as possible, it is difficult to achieve accurate focusing. Therefore, long-time soft X-ray irradiation is unavoidable in order to search a desired site and focus accurately, and damage to the sample due to the long soft X-ray irradiation cannot be avoided.

[0011]

The present invention has been expanded by a soft X-ray light source for irradiating a sample with soft X-rays, and a soft X-ray objective lens for magnifying an image of the sample by soft X-rays. A soft X-ray including a phosphor that converts an image into visible light, an objective lens of an optical microscope that re-enlarges the image converted into visible light, and a visible-light-sensitive image sensor that detects the re-enlarged image. In a microscope, a visible light source for irradiating the sample with visible light is provided, and a magnified image of the sample by the visible light is obtained by the soft X-ray objective lens to enable observation with visible light. You can solve the problem of damage to.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of a first embodiment of a soft X-ray microscope of the present invention. In this embodiment, a laser plasma light source is used as a soft X-ray light source, a spheroidal mirror is used as a condenser lens, and a Schwarzschild type which is a direct-incidence reflecting mirror using a multilayer film is used as an objective lens.

In FIG. 1, when observing a soft X-ray image, laser light emitted from a high-power pulse laser 1 as a soft X-ray light source is provided in a vacuum container 3 by a condenser lens 2. It is focused on the target 4. Vacuum container 3
Has a window (not shown) for introducing laser light into the container. The target 4 is configured as a tape-shaped thin film target, and moves the tape a minute distance for each shot of the pulse laser 1. The tape moving mechanism (not shown) is similar to that of a compact cassette for recording, for example.

The target 4 by the condensed laser light
High-temperature, high-density plasma is generated on the top to generate soft X-rays. Here, as the high-output pulse laser 1, for example, an Nd: YAG laser having an output of 1 J / pulse and a repetition frequency of 10 Hz is used. The generated soft X-rays are irradiated onto the sample 7 in the sample chamber 6 by the condenser lens 5 of the spheroidal mirror using total reflection. The sample chamber 6 has a structure that isolates the sample from the vacuum in order to retain the water content of the sample 7. Therefore, the sample chamber 6 is provided with the window 8 so that the sample 7 can be observed through the window 8. The window 8 is made of Si having a diameter of 200 μm and a thickness of 0.12 μm so that it can transmit soft X-rays and withstand atmospheric pressure.
It is composed of a ₃ N ₄ thin film. The material may be polyimide or the like.

The soft X-rays transmitted through the sample 7 enter the Schwarzschild type objective lens 9. The Schwarzschild type objective lens 9 has a magnification of 100 times and NA = 0.
25, so the resolution is 0.01 μm.
The image of the sample 7 magnified 100 times by the Schwarzschild type objective lens 9 is a phosphor 1
Converted to visible light by 0. The phosphor 10 needs to have a resolution of about 1 μm.
d ₂ O ₂ S: Tb, Gd ₂ O ₂ S: Eu, La
₂ O ₂ S: Tb, La ₂ O ₂ S: Eu, BaM
g ₂ Al ₁₆ O ₂₇ : Eu, CeMgAl ₁₁ O ₁₉ : Tb
, Y ₂ O ₆ Eu, Y, La, Ce,
Eu, Tb, Tm, Yb-based materials and Ca ₁₀
(PO ₄ ) ₆ (F, Cl) ₂ : Sb, Mn, Caw
O ₄ , CsI: Na or the like is used.

By the way, since the soft X-ray microscope has a deep depth of focus of the soft X-ray magnified image, from the viewpoint of conversion efficiency, it is preferable to make the phosphor 10 as thick as possible to convert a large amount of soft X-rays into visible light. It is good, but if it is made too thick, it becomes a defocused image when enlarging the image with the objective lens of the optical microscope, which causes deterioration of the resolution. Therefore, in order to avoid it, the thickness of the phosphor 10 should be as follows. Must be set to.

[0017] That is, the thickness D _F of Phosphor is desirably limited by the depth of focus of the optical microscope objective lens for magnifying the fluorescence image by Phosphor, the numerical aperture of the optical microscope objective and NA _0, fluorescent When the wavelength is λ _F , it is set so as to satisfy D _F <λ _F / (2 · NA ₀ ² ). With this setting, the soft X-rays that have been transmitted without being converted by the phosphor 10 are absorbed by the objective lens of the optical microscope, so there is no risk of degrading the image. However, when the wavelength range of visible light (including ultraviolet light) converted by the phosphor 10 is larger than the chromatic aberration correction area of the objective lens, it is necessary to limit the wavelength area by using an appropriate filter.

The image converted into visible light is re-enlarged by the objective lens 12 of the optical microscope. The objective lens 12 is
In the case of biological use, the magnification is 20 times and NA ₀ 0.7. When the fluorescence wavelength is 0.545 μm (0.612 μm for Tb and Eu), Df is about 0.6 μm, and the phosphor is applied on the cover glass 11 having a thickness of 0.17 mm.

The image magnified 2000 times by the above-mentioned two times magnification passes through a window (not shown) of the vacuum container 3 and is arranged at a pitch of 10 μm in an image intensifier 13 which is an image pickup element sensitive to visible light. MCP1 provided
An image is formed on the photoelectric conversion surface 15 on the surface 4. Basically, one image is detected for each pulse of the pulse laser 1, but integrated averaging processing or the like may be performed to reduce shot noise and the like. Since the resolution of the MCP 14 is about 20 μm because it is provided at a pitch of 10 μm, it is possible to resolve 0.01 μm, which is 1/200 of that.

The MCP 14 is sandwiched between a photoelectric conversion surface 15 and a fluorescent surface 16 which are sensitive to visible light, and the amount of light is amplified in this portion. The fluorescent screen 16 is a lens 17
The image is picked up by the CCD 18 via the, and a final image is obtained by this picking up and observed by a CRT or the like (not shown). When the light intensity is sufficient, it is possible to directly detect the re-enlarged image by an image pickup device such as CCD instead of the image intensifier 13. Also,
When the scattered light of the laser is strong, an image with less noise can be obtained by providing the filter 19 that cuts out a specific wavelength of the laser light so that it can be taken in and out.

The sample observation by visible light in this embodiment will be described below. When exploring the observation site of the sample 7, first, the mirror 20 that reflects visible light is moved to a position indicated by 20 a in the optical path from the target 4 to the condenser lens 5, and the visible light from the visible light source 21 is transferred. It is introduced into the condenser lens 5 using the lens 22. In order to introduce the visible light, the vacuum container 3 is provided with an introduction window (not shown). In addition, the mirror 20 is provided outside the vacuum container 3.
A moving mechanism (not shown) for moving the container from outside the container is provided.

Next, the Schwarzschild type objective lens 9
1 from the phosphor 10 in the optical path from the lens to the objective lens 12.
It is moved to the position indicated by 0a and excluded from the optical path. At the same time, the glass plate 23 that corrects the optical path length change due to the cover glass 11 is moved to the position where the phosphor 10 was present. The glass plate 23 is usually made of the same material and the same thickness as the cover glass 11. The glass plate 23 can be omitted when the phosphor 10 is used as a thin film. Further, outside the vacuum container 3, a moving mechanism (not shown) for moving the glass plate 23 from outside the container is provided. The image of the sample 7 irradiated with visible light by the Schwarzschild type objective lens 9 is formed on the glass plate 23, re-enlarged by the objective lens 12, and then the image intensifier 1
3 is imaged.

Next, in order to perform sample observation, the sample 7 is set in the soft X-ray microscope together with the sample chamber 6, and the air in the vacuum container 3 is exhausted by an exhaust device (not shown), and the vacuum container 3
Make a vacuum inside. At this time, MC that requires a high degree of vacuum
Since P14 is independent of the vacuum vessel 3, it is sufficient that the degree of vacuum in the vacuum vessel 3 is such that it can transmit soft X-rays, and a high degree of vacuum is not required, so that the exhaust work can be performed in a short time. There are advantages. Next, the mirror 20 is moved into the optical path, and the visible light source 21 irradiates the sample 7 with visible light. Then, the phosphor 10 is replaced with the glass plate 23, and the image by the visible light is observed by the image intensifier 13. At that time, when the image is too bright, an attenuator provided so as to be able to be put in and taken out from the optical path is used as a filter 19 for adjusting the brightness of incident visible light, and more light than necessary is not incident on the image intensifier 13. Needless to say,

Next, a sample moving mechanism (not shown) moves the sample 7 together with the sample chamber 6 from the outside of the vacuum container to search for a desired observation site and, at the same time, to perform focusing. Next, the mirror 20 positioned in the optical path between the target 4 and the condenser lens 5 as shown by the dotted line is moved to the position shown by the solid line to exclude it from the optical path, and then the irradiation of visible light is stopped.
Schwarzschild type objective lens 9 to objective lens 12
The phosphor 10 is moved and introduced into the optical path leading to as shown by the solid line. Then, the pulse laser 1 is oscillated for one shot to obtain a soft X-ray image. At this time, needless to say, when there is a lot of noise, in addition to the integration process, various image processes such as storing an image in a memory (not shown) are performed.

In this way, the observation site is selected and focused with visible light before irradiating the sample with soft X-rays, and the sample is exposed to 0.
It is possible to provide a soft X-ray microscope having a simple configuration, which enables sample observation with a resolution of 01 to 0.04 μm. At that time, visible light observation can be performed using the image intensifier 13, which is an image pickup element used for soft X-ray observation, as it is. The objective lens 12 used for re-enlargement of the image
Is replaced with an objective lens with different magnifications mounted on a revolver, and by selecting any objective lens from among these multiple objective lenses, an objective of any magnification from low magnification to high magnification can be selected. Allows selective use of lenses.

By the way, since the phosphor used in the above observation has uneven sensitivity, the image data Ic (x, y) is obtained without the sample 7 placed in the sample chamber 6 to obtain Nc.
The integrated cumulative averaging process is performed, and the reciprocal of the integrated cumulative value obtained is used as correction data C (x, y) to correct sensitivity unevenness. Here, the integration and averaging process is performed in order to remove the influence of shot noise of the detector such as MCP or CCD. By this integrated averaging process, MCP14 and C
It is also possible to reduce the effects of uneven sensitivity between the pixels of the CD 18 and uneven light irradiation by the soft X-ray light source (pulse laser 1). That is, assuming that the value of the integrated average processing N times in order to reduce the noise of the observed image data when the sample 7 is placed in the sample chamber 6 is Io (x, y), the observed image I
(X, y) is

## EQU00002 ## I (x, y) = Io (x, y) .times.C (x, y), and this expression can correct the sensitivity unevenness and the light beam irradiation unevenness.

Further, depending on what kind of material the phosphor is, the agglomerates may be conspicuous. In this case,
By exposing the phosphor 10 while moving a small amount (for example, a fraction of the size of the agglomerate on the phosphor surface) in the direction perpendicular to the optical axis, detecting the image, and performing the average processing of the detected images. Eliminate the effects of materials. that time,
To avoid the influence of vibration, move the phosphor 10 by P
It is preferable to use an electrostrictive element such as ZT. For example, when the size of the agglomerate is 2 μm and the number of times of integration processing is 10, the value of 0.
Since the detection processing is performed while moving by 2 μm, the processing time of 1 second is required because the pulse laser 1 of 10 Hz is used in this embodiment.

FIG. 2 shows the configuration of the second embodiment of the soft X-ray microscope of the present invention. In this embodiment, a synchrotron radiation source is used as a soft X-ray source, a spheroidal mirror is used as a condenser lens, and a grazing-incidence reflection type Walter optical element in which a rotary hyperboloid and a spheroidal surface are integrally processed is used as an objective lens. ing.

In FIG. 2, when observing a soft X-ray image, a soft X-ray 25 having good directivity is emitted from a radiation light source (not shown).
Is radiated into the vacuum container 3, and the soft X-rays 25 are transmitted through the zone plate 26 having the function of the spectroscope to the pinhole 2
It is incident on 7. Since the zone plate 26 has a large axial chromatic aberration and the focal length differs depending on the wavelength, the soft X-ray can be monochromaticized by using the pinhole 27. Light of a certain wavelength in the soft X-ray 25 having good directivity from the radiant light source is condensed by the zone plate 26 at one point. Therefore, the pinhole 2 is placed at the focusing position.
By arranging 7, it is possible to extract only the light of the relevant wavelength behind the pinhole 27. At that time, zone plate 2
An arbitrary wavelength can be selected by changing the distance between 6 and the pinhole 27. The interval is changed by moving the zone plate 26 in the optical axis direction.

A soft X-ray having a wavelength selected by passing through the pinhole 27 is applied to the sample 7 in the sample chamber 6 by the condenser lens 5 having a spheroidal surface. Since the synchrotron radiation source requires a high degree of vacuum, the optical system of the soft X-ray microscope is housed in the vacuum container 3, and the sample chamber 6 has the same structure as that of the first embodiment. The soft X-rays that have passed through the sample 7 are incident on the Wolter type objective lens 28 to be magnified and then form an image on the phosphor 10. After that, the image is re-enlarged by the objective lens 12 of the optical microscope, and an image is picked up by the image intensifier 13 which is an image pickup element having sensitivity to visible light. The details of the soft X-ray imaging unit other than those described above are the same as in the first embodiment.

The sample observation by visible light in this embodiment will be described below. First, the mirror 20 that reflects visible light is moved to a position indicated by 20a in the optical path from the pinhole 27 to the condenser lens 5, and the visible light is introduced into the vacuum container 3 from a visible light source (not shown), and the sample 7 is applied to the sample 7. Irradiate. Next, the visible light reflection mirror 29 is moved to a position indicated by 29a in the optical path from the Walter objective lens 28 to the phosphor 10. This Walter type objective lens 28
Also forms an image of visible light, and the movement of the mirror 29 reflects the visible light and branches it toward the eyepiece (eyepiece) 30 outside the vacuum container. Can be observed through the eyepiece 30.

In this way, the observation site of the sample can be selected while observing with visible light.
It is possible to prevent the sample from being exposed to the rays. In addition, in the case of this soft X-ray microscope, the wavelength of the soft X-ray can be arbitrarily selected. Therefore, obtain an image at a wavelength before and after the absorption edge wavelength of the substance to be observed, and subtract the two images. Thus, the distribution of the substance to be observed can be observed.

[0033]

As described above, according to the present invention, a soft X-ray light source for irradiating the sample 7 with soft X-rays, a soft X-ray objective lens for magnifying an image of the sample by soft X-rays, and magnifying A phosphor that converts the magnified image into visible light, an objective lens of an optical microscope that magnifies the converted image into visible light, and a visible light-sensitive image sensor that detects the magnified image. X
In a line microscope, a visible light source for irradiating the sample with visible light is provided, and an enlarged image of the sample with visible light is obtained by the soft X-ray objective lens to enable observation with visible light. It is possible to solve the problem of damaging the sample.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of a soft X-ray microscope of the present invention.

FIG. 2 is a diagram showing the configuration of a second embodiment of the soft X-ray microscope of the present invention.

FIG. 3 is a diagram for explaining a conventional technique.

FIG. 4 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 1 pulse laser (soft X-ray light source) 2 condenser lens 3 vacuum container 4 target 5 condenser lens 6 sample chamber 7 sample 9 Schwarzschild type objective lens 10 phosphor 12 objective lens 13 image intensifier 14 MCP 15 photoelectric conversion surface 16 fluorescence Surface 18 CCD 19 Filter 20 Mirror 21 Visible Light Source 23 Glass Plate

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 5

[Correction method] Change

[Correction content]

[Formula 1] D _F <λ _F / (2 · NA ₀ ² ) where λ _F :
The wavelength of fluorescence, NA ₀ : The numerical aperture of the objective lens for re-magnification is set to satisfy:
4. The soft X-ray microscope according to any one of 4 above.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

A method of enlarging an image electronically will be described with reference to FIG. Electrons emitted from the electron gun 40 are converged by the condenser electron lens 41 onto the target 42, and the characteristic X-rays (in the case of a soft X-ray microscope, the generated X-rays are generated).
A soft X-ray is generated from among the lines to irradiate the sample 43. The X-rays transmitted through the sample 43 are enlarged and projected onto the photoelectric conversion surface 45 such as CaI by the Walter objective lens 44, and the X-rays are once converted into electrons by the photoelectric conversion surface 45. The electrons are electro-optically re-enlarged by the electronic lens 46, and an enlarged image by the electrons is formed on the MCP 47. M
The image amplified by the CP 47 is converted into visible light by the fluorescent screen 48 and detected by the CCD camera 49. The above system is kept in vacuum by the chamber 50.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

A method of observing a soft X-ray image in FIG. 1 will be described. Laser light emitted from the high-power pulse laser 1 is condensed by a condenser lens 2 onto a target 4 provided in a vacuum chamber 3. The vacuum container 3 is provided with a window (not shown) for introducing laser light into the container. The target 4 is configured as a tape-shaped thin film target, and moves the tape a minute distance for each shot of the pulse laser 1. The tape moving mechanism (not shown) is similar to that of a compact cassette for recording, for example.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

The soft X-rays transmitted through the sample 7 enter the Schwarzschild type objective lens 9. The Schwarzschild type objective lens 9 has a magnification of 100 times and NA = 0.
25, so the resolution is 0.01 μm.
The image of the sample 7 magnified 100 times by the Schwarzschild type objective lens 9 is a phosphor 1
Converted to visible light by 0. The phosphor 10 needs to have a resolution of about 1 μm.
d ₂ O ₂ S: Tb, Gd ₂ O ₂ S: Eu, La ₂ O ₂
S: Tb, La ₂ O ₂ S: Eu, BaMg ₂ Al
₁₆ O ₂₇ : Eu, CeMgAl ₁₁ O ₁₉ : Tb, Y ₂ O ₆ E
u, Y, La, Ce, Eu, Tb, Tm, Yb-based materials, Ca ₁₀ (PO ₄ ) ₆ (F, Cl) ₂ : Sb, M
n, CaWO ₄ , CsI: Na or the like is used.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

The image magnified 2000 times by the above-mentioned two times magnification passes through a window (not shown) of the vacuum container 3 and is arranged at a pitch of 10 μm in an image intensifier 13 which is an image pickup element sensitive to visible light. MCP1 provided
An image is formed on the photoelectric conversion surface 15 on the surface 4. Basically, one image is detected for each pulse of the pulse laser 1, but integrated averaging processing or the like may be performed to reduce shot noise and the like. Since the resolution of the MCP 14 is about 20 μm because it is provided at a pitch of 10 μm, 0.01 μm, which is 1/2000 of that, can be resolved.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 1 pulse laser 2 condenser lens 3 vacuum vessel 4 target 5 condenser lens 6 sample chamber 7 sample 9 Schwarzschild type objective lens 10 phosphor 12 objective lens 13 image intensifier 14 MCP 15 photoelectric conversion surface 16 fluorescent surface 18 CCD 19 Filter 20 Mirror 21 Visible Light Source 23 Glass Plate

Claims (7)

[Claims] 1. A soft X-ray light source for irradiating a sample with soft X-rays,
A soft X-ray objective lens that magnifies an image of the sample by soft X-rays, a phosphor that converts the magnified image into visible light, and an objective lens of an optical microscope that re-magnifies the image converted into visible light. In a soft X-ray microscope including a visible light sensitive image sensor for detecting an enlarged image, a visible light source for irradiating the sample with visible light is provided, and an enlarged image of the sample with visible light is used for the soft X A soft X-ray microscope characterized in that it can be observed with visible light by being obtained with a linear objective lens. 2. A visible light reflecting mirror is provided in the optical path between the soft X-ray light source and the sample so as to be removable so that the soft X-ray optical path and the visible light optical path can be switched.
2. The soft X-ray microscope according to claim 1, wherein a visible light reflection mirror is provided in the optical path between the line objective lens and the phosphor so as to be able to be taken in and out so that the soft X-ray observation optical path and the visible light observation optical path can be switched. 3. A mechanism for providing a visible light reflecting mirror in and out of the optical path between the soft X-ray light source and the condenser lens to switch the soft X-ray optical path and the visible light optical path and to exclude the phosphor from the optical path. The soft X-ray microscope according to claim 1, further comprising: 4. The soft X-ray microscope according to claim 3, wherein an attenuator is provided in an optical path between the visible light source and the visible light sensitive image pickup device so that the attenuator can be inserted and removed. 5. The thickness Df of the phosphor is expressed by the following formula: D _F <λ _F / (2 · NA ₀ ), where λ _F :
The wavelength of fluorescence, NA ₀ : The numerical aperture of the object lens for re-expansion is set to satisfy:
4. The soft X-ray microscope according to any one of 4 above. 6. The image data detected in the state where the sample is present is multiplied by the reciprocal equivalent value of the image data detected in the state where the sample is not present to correct sensitivity unevenness due to the phosphor. The soft X-ray microscope according to claim 1. 7. A plurality of images detected while moving the phosphor by a small amount in the optical axis direction are integrated and averaged,
An observation image in which sensitivity unevenness due to the agglomerates of the phosphor is corrected is obtained.
The soft X-ray microscope according to any one of 1.