JPH09251100A - Soft x-ray microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurate and simple focusing by using an imageforming optical element with large magnitude by providing a measuring means measuring a distance between an observation object and a detector or a distance between an objective lens and a detector. SOLUTION: A beam 2 emitting from an SR light source is allowed to enter a zone plate 3 with a large diameter in order to utilize a light fully. The incident beam 2 is condensed and becomes a primary diffraction light, thereby forming a spot light source 4. A light shielding plate 6 having a pinhole 5 where the beam from the source 4 can pass through is provided just behind the source 4. The beam entering an obliquely incident condenser from the source 4 becomes monochromatic by the plate 3 and pinhole 5. The condenser 7 is of rotary elliptic shape, and the beam from the source 4 is directed to a sample 8. A distance between an objective zone plate 9 and a detector 10 is measured at an error of 1mm so as to obtain the image-forming magnitude accurately.

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 particularly to a high resolution soft X-ray microscope suitable for living body observation, semiconductor inspection and the like.

[0002]

2. Description of the Related Art X-ray microscopes have been attracting attention because they can observe biological samples without treatment and with high resolution. For example, an imaging X-ray microscope collects X-rays emitted from an X-ray source toward a sample by an illumination optical system, and an image of the sample irradiated by the X-rays is detected on a detector by an imaging optical system. The sample is observed by forming an image on.

As an illumination optical system and an imaging optical system which form the optical system of the above-mentioned imaging X-ray microscope, for example, a reflective surface is laminated with a multilayer film having a high reflectance for X-rays of a specific wavelength. The Schwarzschild optical system, the Walter optical system using total reflection, the zone plate optical system using diffraction, and the like are used. Conventional examples combining these optical systems include the following.

(1) A system using zone plates for both the condensing optical system and the imaging optical system (see, for example, JP-A-6-3
47600, X-Ray Microscopy, ed. By G.Sch.
mahland D. Rudolph, Springer Series in Optical Scie
nces, Vol.43, (Springer, Berlin, Heidelgerg 1984)
D. Rudolph et al, "The Gotti, P192-202,"
ngen X-Ray Microscope and X-Ray Microscopy Experim
ents at the BESSY Strage Ring "). (2) A multilayer film reflecting mirror is used for the condensing optical system, and a zone plate is used for the image forming optical system (for example, JP-A-4-26).
4300 publication). (3) An oblique-incidence reflecting mirror is used for the condensing optical system, and a direct-incidence multilayer film reflecting mirror is used for the imaging optical system (for example, Japanese Patent Laid-Open No. 6-
230200). (4) One using an oblique incidence mirror for both the condensing optical system and the imaging optical system (for example, Japanese Patent Laid-Open No. 6-230200). (5) A system using a zone plate and a grazing incidence reflecting mirror for the condensing optical system and a zone plate for the imaging optical system (for example, Japanese Patent Application No. 6-13543). Generally, since the X-ray optical element has a low X-ray transmittance, many imaging optical systems are designed to obtain a high magnification with a single imaging optical element. Is designed to be.

In the imaging optical system (imaging optical element), the deviation of the object point position in the optical axis direction is magnified by the square of the imaging magnification to the deviation of the imaging position. The image will also be different. Therefore, in the visible microscope, in order to keep the imaging magnification constant, the distance (IO) between the image point and the object point
Is often fixed, and in many soft X-ray microscopes, the distance (IO) between the image point and the object point is fixed as in the above-mentioned conventional example.

[0006]

In the above-mentioned conventional example, focusing is performed by adjusting the distance between the sample and the objective lens. However, if the microscope is constructed with high magnification, focusing becomes difficult as shown below. . For example, assuming an optical system of IO = 1 (m), the sample position is 10 (n) when the magnification of the imaging optical element is 100 times.
Even if it is shifted by m), only a displacement of 0.1 (mm) occurs at the image forming position. However, when the magnification of the image forming element is 1000 times, if the sample position is displaced by 10 (nm), the image forming position is changed. 10
A deviation of (mm) will occur. That is, in a microscope in which the magnification of the imaging element is 1000 times, it is necessary to move the sample with a resolution of several nm, and the mechanism for realizing such sample movement with high accuracy becomes complicated and the cost is increased. Further, in the above-mentioned conventional example, since the distance IO is fixed, in order to change the imaging magnification, it is necessary to carry out a troublesome work of exchanging with an imaging optical element having a different focal length.

Further, in the above-mentioned conventional example, since the distance IO is fixed, it is necessary to replace a plurality of X-ray detectors on the same plane when replacing the X-ray detectors as desired. It was Therefore, the switching mechanism and operating mechanism of the X-ray detector are
The layout design becomes difficult because it will be centrally located at the location. This tendency becomes more remarkable as the types of X-ray detectors increase. Further, a detector such as a microchannel plate (MCP) which requires a vacuum degree of 1 × 10 −4 (Pa) or less and a detector such as an X-ray dry plate which has a vacuum degree of 0.1 Pa or less are used properly. In this case, the whole is 1 × 10 -4 (P
a) It is necessary to perform vacuum evacuation until the degree of vacuum is equal to or less than that described above, or to make the structure capable of operating exhaust. However, in the former case, there is a problem that the evacuation time becomes longer,
In the latter case, since a detector switching mechanism and an operating mechanism are added, the layout design becomes more difficult.

The first object of the present invention is to provide a soft X-ray microscope which has a structure using a high-magnification image-forming optical element and which can perform focusing accurately and easily.
The purpose of. A second object of the present invention is to provide a soft X-ray microscope capable of changing the imaging magnification without replacing the imaging optical element. A third object of the present invention is to provide a soft X-ray microscope capable of switching a plurality of detectors and having easy layout design.

[0009]

For the above first purpose,
The configuration of claim 1 of the present invention is the soft X-ray emitted from the soft X-ray source.
In a soft X-ray microscope including an illumination optical system that irradiates an observation target with a line, an objective lens that focuses the soft X-rays from the observation target, and a detector that is movable in the optical axis direction, the detection is performed. It is characterized in that focusing is performed by moving the vessel.

The basic formula of the imaging optical element will be described with reference to the principle diagram of FIG. In FIG. 1, a is the distance from the object point P1 to the principal surface S of the optical element, b is the distance from the principal surface S of the optical element to the image point P2, and f is the focal length of the optical element. At this time, M is the imaging magnification, and the image point P2
If the distance between the object and the object point P1 is IO, the following equation holds.

## EQU1 ## 1 / a + 1 / b = 1 / f (1) b = a.M (2) a + b = IO (3)

According to the soft X-ray microscope of the first aspect of the present invention, focusing is performed by moving a detector that is movable in the optical axis direction. Therefore, precise focusing is performed without providing a high-resolution moving mechanism. You can Therefore,
Focusing can be performed easily and with high accuracy, even though the configuration uses a high-magnification imaging optical element. For example, when IO = 1 (m), the magnification of the imaging optical element is 10
When an imaging optical system with a magnification of 00 is used, IO = 1
Moving the detector with an accuracy of 1 (mm) in the vicinity of (m) is equivalent to performing focusing with an accuracy of 1 (nm) at the sample position. In this case, the actual imaging magnification is about 1000 times.

For the above-mentioned second purpose, the second aspect of the present invention.
In the above configuration, the illumination optical system that irradiates the observation target with the soft X-rays emitted from the soft X-ray light source, the objective lens that focuses the soft X-rays from the observation target, and the movable detection in the optical axis direction. In a soft X-ray microscope including a detector, the maximum value of the distance between the detector and the objective lens is set to 1.5 times or more the minimum value.

According to the soft X-ray microscope of the second aspect of the present invention, the imaging magnification is changed by greatly changing the distance IO so that its maximum value becomes 1.5 times or more of the minimum value. The imaging magnification can be changed without replacing the imaging optical element.

For the above third purpose, the third aspect of the present invention is provided.
In the configuration, the illumination optical system that irradiates the observation target with the soft X-rays emitted from the soft X-ray light source, the objective lens that focuses the soft X-rays from the observation target, and the optical axis that is fixed or inserted into or removed from the optical axis. The observation in a soft X-ray microscope comprising a detector that is movably arranged and at least one other detector that is removably arranged on the optical axis between the detector and the objective lens. The detector is selected by changing the distance between the object and the objective lens to focus soft X-rays on any one of the detectors. .

According to the soft X-ray microscope of the third aspect of the present invention, since the image forming positions of the plurality of detectors are different from each other, the plurality of detectors are not concentrated in one place. , A soft X-ray microscope capable of easily switching a plurality of detectors can be easily designed.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a diagram showing the configuration of the soft X-ray microscope according to the first embodiment of the present invention. The soft X-ray microscope 1 of the first embodiment is configured as a zone plate microscope, and has a synchrotron (SR) as a soft X-ray light source.
It uses a light source. As the soft X-ray light source, a beam emitted from the soft X-ray source needs to be condensed by a zone plate to form a point light source. Therefore, a light source having a strong directivity such as an SR light source is preferably used. Not necessarily S
The light source is not limited to the R light source.

In FIG. 2, a beam 2 emitted from an SR light source (not shown) is incident on a zone plate 3 having a large diameter in order to effectively use the light. The zone plate 3 has an outermost shell line width d = 0.06 (μm) and a diameter of 0.5.
(Mm) and has a function as a spectroscopic element.
The beam 2 incident on the zone plate 3 is focused into a first-order diffracted light and forms a point light source (secondary light source) 4.

Immediately after the point light source 4 on the optical axis, a light shielding plate 6 having a pinhole 5 having a diameter through which the beam from the point light source 4 can pass is provided. Zone plate 3 and pinhole 5
By the above, the beam incident on the oblique incidence condenser 7 from the point light source 4 is monochromatic. This monochromatization is performed in consideration of a large chromatic aberration when a zone plate is used as an objective lens, and can block unnecessary light when using light of a continuous wavelength such as radiated light.

The oblique incidence condenser 7 has a spheroidal shape and irradiates the sample (observation object) 8 with the beam incident from the point light source 4. The zone plate 3, the point light source (secondary light source) 4, the light shielding plate 6 having the pinhole 5 and the oblique incidence condenser 7 constitute an illumination optical system. A sample stage (not shown) allows the sample 8 to perform coarse movement in the optical axis direction (for example, resolution 0.01 μm) and move on a plane perpendicular to the optical axis. The beam that has passed through the sample 8 has the number of ring zones of 500 and the outermost shell line width d = 0.
After passing through the objective zone plate 9 having a diameter of 03 (μm) and a diameter of 0.03 (mm), the light enters the detector 10. Detector 10
Is movable in the optical axis direction by a moving mechanism (not shown), and a measuring mechanism (not shown) for measuring the distance from the objective zone plate 9 to the detector 10 (or the distance from the sample 8 to the detector 10) is provided. Has been. Detector 10
An MCP, a semiconductor image detector, or the like is used as this, and the image of the sample 8 is enlarged and projected on this detector 10.

The zone plate 3 and the objective zone plate 9 are the following equations showing the relationship between the nth zone radius rn of the zone plate when the light source is at infinity, the focal length f, and the wavelength λ.

## EQU2 ## It is designed for the wavelength .lamda. = 4 (nm) based on rn.sub.2 + f2 = (f + n.lamda. / 2) .sup.2 (4). Substituting the above-mentioned conditions into this equation (4), the focal length f
Is 0.45 (mm). At this time, when the distance from the sample 8 to the detector 10 is 450 (mm),
From the equations (1), (2), and (3) described above, the imaging magnification M
Is 998 times.

Next, sample observation in this embodiment will be described. When observing the sample 8, first, while confirming the image from the detector 10, the sample 8 is focused with an accuracy of about 0.01 (μm) by using the moving mechanism of the sample stage. Next, fine adjustment is performed using the moving mechanism of the detector. Since the imaging magnification M is 998 times,
In this fine adjustment, the maximum value of the detector 10 is 0.01 (μm) × 998 × 998 = 9960 (μm)
= 9.96 (mm). In addition, the detector 1 with an accuracy of 1 (mm)
This is equivalent to moving the sample stage with an accuracy of 1 (nm) by moving 0 in the optical axis direction to perform focusing.

Further, the objective zone plate 9 and the detector 10
By measuring the distance between and with an error of 1 (mm), the imaging magnification M can be accurately obtained. For example,
When the distance between the objective zone plate 9 and the detector 10 when the object is in focus by the focusing is 452 (mm) ± error 1 (mm), the imaging magnification M can be taken. Value is 1001 times to 1006
It can be limited to a value up to double.

According to the present embodiment, highly precise focusing can be performed by using the moving mechanism of the sample stage and the moving mechanism of the detector, which are not highly accurate, in combination. Further, the imaging magnification M is set to 1 by measuring the distance between the detector 10 and the objective zone plate 9 which is an imaging optical element with a relatively easy accuracy of 1 mm.
It can be limited by an error within%.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the same soft X-ray microscope (see FIG. 2) as in the first embodiment is used to observe the sample while changing the imaging magnification. The soft X-ray microscope of the present embodiment is different from the soft X-ray microscope of the first embodiment in that it has a moving mechanism (not shown) for the light shield 6 having the zone plate 3 or the pinhole 5. Is different.

First, as in the first embodiment, the detector 10
When the sample 8 was focused with an accuracy of about 0.01 (μm) by using the moving mechanism of the sample stage while confirming the image from the above, the distance between the objective zone plate 9 and the detector 10 was It was 450 (mm). This 4
The value of 50 (mm) is the minimum value of the distance. Then, the sample 8 is moved to 0.
The objective zone plate 9 is moved closer to the objective zone plate 9 by 0.15 (μm) with a movement accuracy of about 01 (μm). After that, when the detector 10 is moved by using the moving mechanism of the detector to bring it into a focused state, the distance between the objective zone plate 9 and the detector 10 is 675 (mm) ± error 1 (mm )
Met. This value of 675 (mm) is the maximum value of the distance between the objective zone plate 9 and the detector 10.
The imaging magnification M at this time can be limited to a value between 1498 times and 1500 times from the expressions (1), (2), and (3).

According to the present embodiment, by changing the distance between the sample 8 and the objective zone plate 9, the imaging magnification can be easily increased without exchanging the objective zone plate 9 which is the imaging optical element. Can be changed. Further, the imaging magnification M is set to 1 by measuring the distance between the detector 10 and the objective zone plate 9 which is an imaging optical element.
It can be limited by an error within%.

Next, a third embodiment of the present invention will be described.
In the third embodiment, similar to the first embodiment, the soft X-ray microscope having the arrangement shown in FIG. 2 is used to select the wavelength of the soft X-rays incident on the sample to change the imaging magnification. While observing, the sample is observed. The soft X of this embodiment
The line microscope is different from the soft X-ray microscope of the first embodiment in that it has a moving mechanism (not shown) for the light shield plate 6 having the zone plate 3 or the pinhole 5 and the value of each optical element. To do.

First, as in the first embodiment, the detector 10
When the sample 8 was focused with an accuracy of about 0.01 (μm) using the above stage moving mechanism while checking the image from FIG. The distance from the detector 10 is 81 (m
m). The imaging magnification M at this time is (1),
It is about 180 times that of the formulas (2) and (3), and the distance between the sample 8 and the objective zone plate 9 is 0.4525 (mm).
It is.

By the way, when the zone plate 3 or the shading plate 6 having the pinhole 5 is moved in the optical axis direction by using the moving mechanism of the shading plate 6 having the zone plate 3 or the pinhole 5, it passes through the sample 8. Beam wavelength λ
Changes, and thereby the focal length f of the objective zone plate 9 also changes. Therefore, the wavelength of the soft X-rays incident on the sample 8 can be selected by moving the zone plate 3 or the light shielding plate 6 having the pinhole 5 by a minute distance. Therefore, in the present embodiment, the beam transmitted through the sample 8 is selected. The wavelength λ of is shifted from 4 (nm) to 3.98 (nm). The focal length of the objective zone plate 9 at this time is
From equation (4), f = 0.45226 (mm). In this state, if the position of the sample 8 is not changed, the imaging magnification M is 1884 times, and the distance between the detector 10 and the objective zone plate 9 which is the imaging optical element is 853 (m).
m).

According to the present embodiment, by slightly changing the wavelength of the beam incident on the objective zone plate 9, the imaging magnification is largely changed without replacing the objective zone plate 9 which is the imaging optical element. Can be made.

In the first to third embodiments described above, by changing the position of the zone plate 3 or the light shielding plate 6 having the pinhole 5 in the optical axis direction, it passes through the sample 8 and the objective zone plate 9 is passed. Although the wavelength of the soft X-ray beam incident on is selected, the wavelength may be selected using another spectroscopic element such as a multilayer film.

FIG. 3 is a view showing the arrangement of the soft X-ray microscope according to the fourth embodiment of the present invention. The soft X-ray microscope 11 of the fourth embodiment uses a laser plasma light source 12 as a soft X-ray light source.
Is used. In FIG. 3, a laser plasma light source 1
The beam 13 of soft X-rays emitted from the beam 2 enters the oblique incidence condenser 14. The oblique incidence condenser 14 has a spheroidal shape and irradiates the beam 13 onto the sample 15. The sample 15 can be roughly moved in the optical axis direction (for example, resolution 0.01 μm) and moved on a plane perpendicular to the optical axis by a stage (not shown).

The beam that has passed through the sample 15 and diffracted is
The light enters the MCP 17 as a detector through the Schwarzschild type objective lens 16, and the image of the sample 15 is enlarged and projected on the MCP 17. As the Schwarzschild type objective lens 16, for example, an imaging magnification M = 224 times, a numerical aperture NA = 0.25, a focal length f = 4.417 (mm), a mirror surface interval = 24.686 (mm), and a convex mirror Radius of curvature =
6.541 (mm), effective diameter of convex mirror = 2.2 (m
m), the radius of curvature of the concave mirror = 32.125 (mm), and the effective diameter of the concave mirror = 18.8 (mm). In the present embodiment, in addition to the MCP 17 described above, an X-ray dry plate 18 that can be inserted into and removed from the X-ray optical axis is provided as a detector, and the distance (IO) between the sample 15 and the MCP 17 is 20.
00 (mm), and the distance (IO) between the sample 15 and the X-ray dry plate 18 is 1000 (mm).

The above optical system is housed in a vacuum container 19. The vacuum chamber 19 is divided into vacuum chambers 23, 24 (24a, 24b) and 25 by the beryllium filter 20 shown in FIG. 3 and the gate valves 21 and 22 shown in FIG. 5, and the vacuum chambers 23, 24 and 25 are A vacuum exhaust device (not shown) can individually perform vacuum exhaust. If the degree of vacuum of about 0.1 (Pa) is secured in the optical path of the X-rays, the influence of absorption hardly occurs.
No. 4 should be set to this degree of vacuum. On the other hand, the vacuum chamber 25
Uses the MCP17, it is necessary to make the degree of vacuum 1 × 10 −4 (Pa) or less.
Has the function of maintaining the differential pressure between the above vacuum levels. In addition,
The vacuum container 19 is provided with a shutter 26 for taking the X-ray dry plate 18 in and out of the vacuum chamber 24a.

Next, sample observation in this embodiment will be described. When observing the sample 15 with the MCP 17, first, as shown in FIG.
Leave 2 open. Where IO = 2000 (m
m), the imaging magnification M is 451 times from the above equations (1), (2) and (3). At this time, the distance between the sample 15 and the principal surface of the Schwarzschild type objective lens 16 is 4.427 (mm).

On the other hand, when the sample 15 is photographed by the X-ray dry plate 18, the gate valve 22 is closed as shown in FIG. 4 and then the X-ray dry plate 18 is inserted on the optical axis. Here, since IO = 1000 (mm), the imaging magnification M is 224 times from the above equations (1), (2), and (3). At this time, the distance between the sample 15 and the principal surface of the Schwarzschild type objective lens 16 is 4.437 (mm). The distance between the sample 15 and the principal surface of the Schwarzschild type objective lens 16 is changed by moving the Schwarzschild type objective lens 16 in the optical axis direction by a moving mechanism (not shown).
7. One of the X-ray dry plates 18 is selected as the detector.

The replacement of the X-ray dry plate 18 after photographing is performed as follows. That is, first, as shown in FIG. 5, the gate valves 21 and 22 are closed, and then the vacuum chamber 24a is closed.
To the atmosphere, and then the shutter 26 is opened to replace the photographed X-ray dry plate 18 with a new X-ray dry plate 18. After that, the shutter 26 is closed and the vacuum chamber 24a is evacuated, and when the pressure difference between the vacuum chamber 24a and the vacuum chamber 23 and the pressure difference between the vacuum chamber 24a and the vacuum chamber 24b become small, the gate valve 21, Open 22. By replacing the X-ray dry plate 18 in the above-described series of procedures, it is possible to prevent a differential pressure of 0.1 (Pa) or more from being applied to the beryllium filter 20.
0 can be made thin, and absorption of X-rays can be avoided.

According to the present embodiment, since a plurality of (two types in this case) detectors are separated in the optical axis direction, it is easy to arrange the plurality of detectors in the vacuum container, and therefore, This facilitates layout design of multiple detectors.
Further, since it is possible to dispose a shutter, a filter and the like between the detectors, it is easy to switch the detectors when selectively using a plurality of detectors having different vacuum levels to be operated.

Although two types of detectors are used in this embodiment, it is possible to use three or more types of detectors. In this case, the effect of facilitating the layout design of the plurality of detectors described above becomes more remarkable. In addition, a soft X-ray microscope is configured by combining the configuration of selectively using the plurality of detectors of the present embodiment with the illumination optical system and the objective lens portion of the above-described first to third embodiments. Good. In that case, one of the detectors 17 and 18 can be selected by moving the zone plate 3 or the pinhole 4 in the optical axis direction.

When a detector requiring a high voltage (MCP17 in this embodiment) is used, the detector is shown in FIG.
If the detector is arranged at the rearmost end of the optical axis as shown in, the detector can be fixed because it does not need to be moved, which is advantageous in terms of safety. Therefore, as shown in FIG.
CP) 17 fixed on the optical axis, detector (X-ray dry plate) 18
Although the MCP 17 is removably arranged on the optical axis, the MCP 17 may be removably arranged on the optical axis. In addition to the X-ray dry plate 18, another detector may be provided between the Schwarzschild type objective lens 16 and the MCP 17.

Note that the present invention is not limited to the above-described example, and various changes or modifications can be made. For example, an illumination optical system that irradiates the observation target with soft X-rays emitted from a soft X-ray light source, an objective lens that focuses the soft X-rays from the observation target, and a detector that is movable in the optical axis direction. In a soft X-ray microscope including: a soft X-ray microscope, the imaging magnification of the objective lens is changed by changing the distance between the detector and the objective lens. Good (Appendix 1). In that case, since the imaging magnification is changed by changing the distance between the detector and the objective lens, the imaging magnification can be easily changed without replacing the optical element.

The illumination optical system for irradiating the observation object with the soft X-rays emitted from the soft X-ray light source, the objective lens for focusing the soft X-rays from the observation object, and the movable in the optical axis direction. In a soft X-ray microscope including a detector, a wavelength selecting means for selecting a wavelength of soft X-rays incident on the observation object is provided, and a wavelength of soft X-rays incident on the observation object by the wavelength selecting means. The soft X-ray microscope may be characterized in that the imaging magnification of the objective lens is changed by selecting (Appendix 2). In that case, since the imaging magnification is changed by selecting the wavelength of the soft X-ray incident on the observation object, the imaging magnification can be easily changed without replacing the optical element.

Further, a zone plate which receives a soft X-ray emitted from a soft X-ray light source and has a good directivity to form a secondary light source, and a zone plate which is provided immediately after the secondary light source and is movable in the optical axis direction. An illumination optical system that includes a pinhole and an oblique incidence mirror that irradiates an observation target with soft X-rays from the secondary light source, and focuses the soft X-rays from the observation target. In a soft X-ray microscope including a zone plate type objective lens and a detector that is movable in the optical axis direction, the wavelength of the soft X-ray that irradiates the observation target by moving the pinhole in the optical axis direction. Is provided to select the wavelength of the soft X-rays incident on the observation object by the wavelength selection means, thereby changing the imaging magnification of the objective lens. It may be an X-ray microscope Additional Item 3). In that case, by utilizing the characteristic of the zone plate type objective lens that the focal length changes when the wavelength of the incident light changes, the observation target is kept while the distance between the zone plate type objective lens and the observation object is fixed. Since the imaging magnification is changed by selecting the wavelength of the soft X-ray incident on the object, the imaging magnification can be easily changed without replacing the optical element.

Further, a zone plate movably provided in the direction of the optical axis for forming a secondary light source upon incidence of soft X-rays having good directivity emitted from the soft X-ray light source, and immediately after the secondary light source. Pinhole provided in the X and the soft X from the secondary light source.
An illumination optical system including an oblique incidence mirror for irradiating an observation target with a line incident on a spheroid, a zone plate type objective lens for focusing soft X-rays from the observation target, and a movement in the optical axis direction. In a soft X-ray microscope equipped with a possible detector, wavelength selecting means is provided for selecting the wavelength of the soft X-rays that irradiate the observation object by moving the zone plate in the optical axis direction. The soft X-ray microscope may be characterized in that the imaging magnification of the objective lens is changed by selecting the wavelength of the soft X-rays incident on the observation object by means (Appendix 4). In that case, by utilizing the characteristic of the zone plate type objective lens that the focal length changes when the wavelength of the incident light changes, the observation target is kept while the distance between the zone plate type objective lens and the observation object is fixed. Since the imaging magnification is changed by selecting the wavelength of the soft X-ray incident on the object, the imaging magnification can be easily changed without replacing the optical element.

Further, a zone plate that receives a soft X-ray emitted from a soft X-ray light source and has a good directivity to form a secondary light source, and a zone plate that is movable immediately after the secondary light source in the optical axis direction. An illumination optical system that includes a pinhole and an oblique incidence mirror that irradiates an observation target with soft X-rays from the secondary light source, and focuses the soft X-rays from the observation target. Objective lens, detector fixedly or removably arranged on the optical axis, and at least one other detector removably arranged on the optical axis between the detector and the objective lens In the soft X-ray microscope including, the soft X-ray microscope may be characterized in that any one of the detectors is selected by moving the pinhole in the optical axis direction. Item 5). In that case, since the image forming positions of the plurality of detectors are different from each other, the plurality of detectors are not centrally arranged in one place, and the soft X-ray that can easily switch the plurality of detectors. The microscope can be easily designed.

Further, a zone plate movably provided in the optical axis direction for forming a secondary light source upon incidence of soft X-rays having good directivity emitted from the soft X-ray light source, and immediately after the secondary light source. Pinhole provided in the X and the soft X from the secondary light source.
An illumination optical system including an oblique incidence mirror for irradiating an object to be observed with a ray incident on a spheroid, an objective lens for focusing soft X-rays from the object to be observed, and fixing or inserting / removing on / from the optical axis. A zone of a soft X-ray microscope comprising a detector that is movably disposed and at least one other detector that is removably disposed on an optical axis between the detector and the objective lens. The soft X-ray microscope may be characterized in that any one of the detectors is selected by moving the plate in the optical axis direction (Appendix 6). In that case, since the image forming positions of the plurality of detectors are different from each other, the plurality of detectors are not centrally arranged in one place, and the soft X-ray that can easily switch the plurality of detectors. The microscope can be easily designed.

Further, in the soft X-ray microscope according to any one of claims 1 to 3 and appendixes 1 to 6, the distance between the observation object and the detector or the objective lens and the detection. A soft X-ray microscope may be provided with a measuring means for measuring the distance to the instrument (Appendix 7).
In that case, the imaging magnification (effective magnification) of the objective lens of the soft X-ray microscope can be easily obtained.

[Brief description of drawings]

FIG. 1 is a principle diagram of a soft X-ray microscope of the present invention.

FIG. 2 is a diagram showing a configuration of a soft X-ray microscope according to first to third embodiments of the present invention.

FIG. 3 is a diagram showing a configuration of a soft X-ray microscope according to a fourth embodiment of the present invention.

FIG. 4 is a diagram for explaining the operation of the soft X-ray microscope according to the fourth embodiment.

FIG. 5 is a diagram for explaining the operation of the soft X-ray microscope according to the fourth embodiment.

[Explanation of symbols]

 1 Soft X-ray microscope 2 Beam 3 Zone plate 4 Point light source (secondary light source) 5 Pinhole 6 Light shield 7 Oblique incidence condenser 8 Sample (observation target) 9 Objective zone plate 10 Detector

Claims (3)

[Claims] 1. An illumination optical system for irradiating an object to be observed with soft X-rays emitted from a soft X-ray light source, and soft X from the object to be observed.
A soft X-ray microscope comprising an objective lens for focusing rays and a detector movable in the optical axis direction, wherein focusing is performed by moving the detector. 2. An illumination optical system for irradiating an object to be observed with soft X-rays emitted from a soft X-ray light source, and soft X from the object to be observed.
In a soft X-ray microscope including an objective lens that focuses a line and a detector that is movable in the optical axis direction, the maximum value of the distance between the detector and the objective lens is 1.5 times the minimum value. A soft X-ray microscope characterized by the above. 3. An illumination optical system for irradiating an object to be observed with soft X-rays emitted from a soft X-ray light source, and soft X from the object to be observed.
An objective lens for focusing a line, a detector fixedly or removably arranged on the optical axis, and at least 1 removably arranged on the optical axis between the detector and the objective lens.
A soft X-ray microscope comprising two other detectors, wherein the soft X-rays are focused on any one of the detectors by changing the distance between the observation object and the objective lens. A soft X-ray microscope characterized in that the detector is selected.