JPH0694900A - Vacuum optical system - Google Patents

Abstract

PURPOSE:To enable the accuracy in the alignment of an optical system to be secured by supporting the resting table of the optical system by a part whose displacement is small within a specified range even when a vacuum container is deformed due to the change in atmospheric pressure. CONSTITUTION:A metallic target 1, a capacitor lens 2, an objective lens 3 and a reflection mirror 4 are provided on stages 7 through 10 over a plate 6 respectively in an vacuum container 5. And a soft X-ray detector 11 and a reflection mirror 12 are also provided on stages 15 and 16 over a plate 14 in a vacuum container 13. Each plate 6 and 14 is supported at three points, that is, at end sections 5a through 5c, and 13a through 13c of the bottom plates of the vacuum containers 5 and 13 respectively. And the movement of the stages 7 through 10, 15 and 16 is driven through universal joints. By this constitution, when the vacuum is drawn, each plate 6 and 14 is supported by means of three point suspension in opposition to the deformation of the vacuum containers 5 and 13, and even when each stage is driven, no transmission of unnecessary force is made because of the aforesaid constitution, optical alignment therefore will never be out of order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum optical system having a vacuum container for storing an optical system used in a vacuum, for example, a soft X optical system.
It relates to an optical system using a line.

[0002]

2. Description of the Related Art In recent years, research on soft X-ray optics has become popular due to advances in light sources for soft X-rays such as synchrotron radiation. Regarding semiconductor exposure apparatuses, the line width transferred is becoming narrower with the miniaturization of integrated circuits, and the wavelength of light used for exposure is approaching from the ultraviolet light to the soft X-ray region. Regarding the microscope, wavelengths from 22Å to 44, which are said to be suitable for living body observation
Attention has been paid to the observation in the so-called "water window" area of Å.
Further, with respect to the analyzer, since there are many absorption edges of elements in the soft X-ray region, application to elemental analysis has been attempted.

Since soft X-rays are highly absorbed by the atmosphere,
Although it is necessary to assemble the optical system in a vacuum, as a supporting means of the optical system, there are a manipulator attached to a vacuum flange and a stage directly attached to a vacuum container, and these are used for alignment.

[0004]

By the way, in the conventional vacuum optical system, a) as shown in FIG. 14, a stage which is a mounting base of the optical system also serves as a vacuum container or a vacuum flange or is directly mounted on them. Therefore, if vacuum exhaust is performed after alignment in the atmosphere, as shown in FIG.
Alignment may be misaligned due to deformation of the vacuum container due to atmospheric pressure, or b) In order to drive the stage as a moving mechanism in the vacuum container in a vacuum state, a vacuum motor or high voltage that requires heat radiation measures should be used. Since the PZT element to be used is required, the size of the entire apparatus becomes large, and in c) observation by soft X-ray, it takes a long time to reach a high vacuum required by a detector using a high voltage such as a photomultiplier tube. Or d) a thin film for containing the observation object, an ultra-thin film filter used for removing unnecessary light during soft X-ray observation, and a thin film window for extracting soft X-rays out of the vacuum container. However, there is a problem that the above components are destroyed by a rapid flow of air during vacuum evacuation, and it is not always easy to use.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a vacuum optical system which is compact and easy to use. is there.

[0006]

A vacuum optical system according to the present invention is a displacement which is transmitted to an optical system to be used even if a displacement of the vacuum container occurs due to the deformation of the vacuum container due to a change in atmospheric pressure in the vacuum container. An optical system mounting member is provided in the vacuum container, the optical system mounting member being supported by a portion having a small displacement transmission amount that does not exceed a predetermined variation error amount determined by the accuracy required for the optical system.

[0007]

According to this vacuum optical system, the alignment of the optical system can be maintained before and after the evacuation of the vacuum container and the opening to the atmosphere. That is, for example, as shown in FIGS. 1 and 2, when the entire optical system is on a plate which is an optical system achievement member, if the deformation amount of the member due to the displacement of the vacuum container is smaller than the accuracy required for the optical system. The alignment accuracy of the optical system is maintained before and after the vacuum container is evacuated and the atmosphere is opened.

If a device having a moving mechanism installed on the optical system mounting member and a driving mechanism attached to the vacuum container are connected using a power transmission device having a means capable of absorbing deformation of the vacuum container, Since the displacement is not transmitted to the moving mechanism even if the vacuum container is deformed, the moving mechanism can be driven from the outside without causing misalignment in the alignment of the optical system,
The device has a simple structure and is compact.

A soft X-ray detector for detecting soft X-rays converged by a soft X-ray lens for condensing soft X-rays emitted from a soft X-ray source on an object, and a detection for storing the soft X-ray detector. By providing a vacuum container for a container, a pipe connecting the vacuum container and a vacuum container for a detector, and a gate valve provided in the middle of the pipe and capable of vacuum-insulating the two vacuum containers. The time required to reach the required vacuum degree is short, and the rapid flow of air in the vacuum container can be reduced.

As described above, according to the present invention, even if the container is deformed before and after evacuation, the alignment of the optical system in the vacuum container is not disturbed, and the moving mechanism in the vacuum container can be operated from the outside. Vacuum optics. Furthermore, during soft X-ray observation, the apparatus is a device that does not destroy the internal thin film structure because the vacuum exhaust time is short.

The present invention is not limited to the soft X-ray optical system,
It can be applied to all optical systems used in vacuum, for example, optical systems using ultraviolet light or visible light.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 3 and 4 are a plan view and a side view of a first embodiment of a soft X-ray optical system according to the present invention. In this embodiment, a soft X-ray microscope is used as an optical system, a laser plasma light source is used as a soft X-ray light source, and a vacuum container and an exhaust turbo molecular pump are installed on a vibration isolation table. Reference numeral 1 is a metal target that serves as an X-ray source, 2 is a spheroidal condenser lens, 3 is a Schwarzschild type objective lens, 4 is a visible light reflection mirror, and these are plates placed in a vacuum container 5. It is installed on each of the stages 7, 8, 9, and 10 on the No. 6 stage. The plate 6 is supported at three points on the ends 5a, 5b, 5c of the bottom plate, which is less deformable in the rectangular vacuum container 5. Reference numeral 11 is a soft X-ray detector such as a microchannel plate with a fluorescent screen (hereinafter referred to as MCP) that emits light at a wavelength different from that of the incident X-ray, and 12 is a visible light coated with an antireflection film for light of the wavelength of the incident laser Light reflecting mirrors are installed on the stages 15 and 16 on the plate 14 placed in the vacuum container 13, respectively. Similarly to the plate 6, the plate 14 has an end portion 13a of the bottom plate of the vacuum container 13,
It is supported by 13b and 13c at three points. Reference numeral 17 is a pipe that connects the vacuum container 5 and the vacuum container 13, and 18 is a gate valve that can insulate the vacuum container 5 and the vacuum container 13 in a vacuum manner and function as independent vacuum systems. The gate valve 18 includes a vacuum container 5 and a vacuum container 1.
It can be opened and closed when both of them are in the atmosphere or both in vacuum, and the alignment and focusing of the optical system can be performed in the atmosphere. Further, a plurality of light shielding plates 19 are housed in the pipe 17. 20 is a visible light source, 21
Is a visible eyepiece lens coated with an antireflection film for the light of the wavelength of the incident laser, 22 is a high-power pulse YAG laser, 23 is an optical fiber, 24 is a condenser lens, 25 is a sample, 26 is a sample stage, and 27 is optical. An anti-vibration table that supports the entire system, and 28 is a soft X-ray filter for removing vacuum ultraviolet light.

The visible light reflection mirror 4 is a metal target 1.
It is arranged in the soft X-ray optical path between the condenser lens 2 and the condenser lens 2 so as to be freely inserted and removed, and reflects the visible light that has entered the vacuum container 5 from the visible light source 20 and makes it substantially the same as the soft X-ray. It is guided along the axis and made incident on the objective lens 3. Further, the visible light reflection mirror 12 includes the objective lens 3 and the soft X-ray detector 11
Is arranged in the soft X-ray optical path between and so that the visible light from the objective lens 3 is reflected and separated from the optical axis of the soft X-ray, and this is received by the soft X-ray detector 11. The image is formed at a position conjugate with the surface. The visible light image on the optical path separated by the visible light reflecting mirror 12 can be observed from the outside of the vacuum container 13 via the eyepiece lens 21. These form an observation system for visible light. The exhaust system for the vacuum container 5 and the vacuum container 13 is, as shown in FIG.
1, 202, turbo molecular pumps 203, 204, and conductance valves 205, 2 having variable cross-sectional areas of exhaust diameter
06 and butterfly valves 207 arranged at a plurality of positions.

The laser light from the high-power pulsed YAG laser 22 is guided by an optical fiber 23 to just before a condenser lens 24 coated with an antireflection film for the wavelength of the laser light, and is collected on the metal target 1 by the condenser lens 24. Light up. The soft X-ray emitted from the target 1 is focused on the sample 25 by the condenser lens 2 and transmitted through the sample 25.
The diffracted soft X-rays are converged on the soft X-ray detector 11 by the objective lens 3 and observed through the fluorescent screen of the detector. Incidentally, the condenser lens 2 is a spheroidal mirror of oxygen-free copper, and the Schwarzschild optical system which constitutes the objective lens 3 by reflecting the soft X-rays with respect to the soft X-rays in a predetermined wavelength range. Although it is formed by coating a multilayer film having a reflectance distribution, these have a large reflectance also with respect to visible light and thus can be used as a lens for visible light.

FIG. 6 shows the plate 30 in the vacuum container 301.
FIG. 3 is a schematic view of a mechanism for operating a stage (moving mechanism) 302 installed on 0 from outside the vacuum container. The rotation introducing terminal 303 and the universal joint 304 are used to drive the micrometer 305 of the stage 302 in the vacuum container, and the rotation introducing terminal 306 and the flexible shaft 307 drive the micrometer 308. Three
Reference numeral 09 is a handle for rotating the universal joint 304 and the flexible shaft 307.

FIG. 7 shows a plate 40 in a vacuum vessel 401.
2 is a schematic view of a mechanism for operating a stage 403 that can be fixed on the second stage from outside the vacuum container. FIG. The stage 403 is provided on a surface along the longitudinal axis direction of the support base 404A, and fixed terminals arranged at the end of the support base 404A so that the longitudinal axis direction is perpendicular to the plate 402. (Screws, screws, etc.) are provided, and the support base 404A is fixedly supported on the fixed base 405 via the fixed terminals. A micrometer 406 is further provided on the fixed base 405 so that the micrometer 406 can be operated from the outside of the vacuum container 401 by using a rotation introduction terminal and a universal joint (not shown). Also, the stage 40
A wire 407 is connected to one end of the wire 3, and the other end of the wire is connected to the micrometer 406 via pulleys 408 and 409. The stage 403 is operated by operating the micrometer 406 so that the wire 40
7, via the pulleys 409, 408, it is moved up and down along the longitudinal axis direction of the support base 404A.

Further, the support 404A is removed, and instead, the longitudinal axis is set to a predetermined angle θ with respect to the plate 402.
The support base 404B provided with the fixed terminal at the end portion so that the support base 405 can be tilted only is fixedly supported by the fixed base 405.
Thus, as shown in FIG. 8, the stage 403 is moved to the plate 402 by operating the micrometer 406.
It is possible to move in the angle θ direction.

As described above, the plurality of support bases 404A, 40
By using 4B or the like, the moving direction of the stage 403 can be set arbitrarily. In addition, the support base 404
A, 404B and the fixed base for holding the fixed base 405 are installed with a rail with a fixed groove that can fix the fixed terminals in stages,
If the change from FIG. 7 to FIG. 8 is made by moving the connection position between the end of the support base and the fixed base 405 instead of the method of removing and replacing the support base as described above, the longitudinal direction of the support base It is possible to arbitrarily select the inclination angle θ of.

FIG. 9 shows a plate 50 in a vacuum container 501.
0 is a schematic view of a mechanism for operating the stage 502 fixed on the outer surface of the vacuum vessel from outside the vacuum container. The stage 502 is driven by pushing and pulling the groove portion 505 of the stage 502 with the hook 504 at the tip of the linear introduction terminal 503. . There is a play between the hint 504 and the groove 505 so that the stage 502 does not move even if the vacuum container 501 is deformed. Further, the stage 502 is set because the leaf spring 506 having the steel ball 502a attached thereto is attached to the stage 502, and the rail 508 having the section 508a cut at a right angle to the moving direction of the stage is attached to the stage attachment base 507. It is designed to reliably stop in several positions. The mechanism from FIG. 6 to FIG.
It is used in the stage of FIG. 4 depending on the position of the micrometer, the driving accuracy of the stage, and the like. Further, the vacuum container is provided with a window so that the scale of the micrometer of each stage and the position of the stage can be visually observed from the atmosphere. In the above description, the driven members such as the stage and the stage support are the moving mechanism, the members such as the handle, the rotation introducing terminal and the linear introducing terminal are the driving mechanism, and the moving mechanism and the driving mechanism such as the universal joint and the flexible shaft. The members that connect to each other and transmit power form a power voltage mechanism.

Although this embodiment is constructed as described above,
Next, the operation will be described. First, when the gate valve 18 is opened and the visible light mirrors 4 and 12 are inserted into the soft X-ray optical path without evacuating the vacuum containers 5 and 13, the visible light emitted from the visible light source 20 is reflected by the visible light mirror 4. The optical path is bent and guided to the condenser lens 2. The visible light guided to the condenser lens 2 is condensed by the condenser lens 2 and illuminates the sample 25. The visible light transmitted and diffracted through the sample 25 is guided to the objective lens 3, the visible light guided to the objective lens 3 is subjected to a converging action by the objective lens 3, and its optical path is bent by the visible light mirror 12, and then the soft X A sample image is enlarged and formed at a position conjugate with the light receiving surface of the line detector 11. Then, this sample image is visually observed through the eyepiece lens 21. Therefore, the operator can
The image can be observed, and the alignment and focusing can be performed by utilizing the mechanism illustrated in FIGS. 6 to 9 while observing with the visible light.

Next, the gate valve 18 is closed to perform vacuum evacuation, and the plates 16 and 14 are evacuated to the vacuum vessels 5 and 13, respectively.
Bottom plate ends 5a, 5b, 5c; 13a, 13b, 13
Since they are only in contact with each other at c, the alignment of the optical system on the plates 16 and 14 will not be disturbed even when the vacuum container is deformed. Further, since the power for driving each stage is transmitted using the above-described power transmission mechanism, even if the vacuum vessel side plate is deformed, the flexible shaft 307 is deformed or the universal joint 304 is expanded or contracted, which is unnecessary for the stage. Since no force is applied, the alignment does not go wrong.

In evacuation, first, the rotary pumps 201 and 202 are started with the conductance valves 205 and 206 closed, and the conductance valves 20
Vacuum evacuation is performed while gradually opening 5, 206. However, if the vacuum evacuation is gradually performed in this way, a violent gas flow does not occur in the vacuum container, and thus alignment may be misaligned due to impact or the internal thin film structure may be reduced. Will not be destroyed. Thus, when the degree of vacuum inside each vacuum container reaches several torr, even if the conductance valves 205 and 206 are fully opened, a violent gas flow no longer occurs inside. Also, since it does not take so long to reach this degree of vacuum, the loss of time due to exhaust while gradually opening the conductance valves 205, 206 is the ratio of the time required to reach an observable high degree of vacuum. Small against.

The gate valve 18 installed in the pipe 17 between the vacuum containers prevents gas from flowing from the other vacuum container at the initial stage of evacuation to prevent the internal thin film structure from being destroyed and perform the evacuation in two systems. Therefore, the detector can always be kept in a high vacuum, and the time from the start of vacuum evacuation to the observation can be greatly shortened.

By connecting the vacuum vessels 5 and 13 with a pipe 17 having a small conductance (reciprocal of flow resistance), differential evacuation can be performed, and soft X-rays are generated in the vacuum vessel 5.
Even if the gate valve 18 is opened in a vacuum degree of 1 × 10 ⁻⁴ torr necessary for permeation, the vacuum degree in the vacuum container 13 is 1 × 1.
It can be maintained at 0 ^-6 torr, and it is not necessary to wait for a long time until the inside of the vacuum container 5 becomes a high vacuum state. The connection pipe 17 is
It is desirable that the inner diameter is small in order to reduce the conductance, but when the inner diameter is reduced, diffuse reflection of visible light and vacuum ultraviolet light on the inner surface of the pipe increases. The light shielding plate 19 serves to prevent diffuse reflection and reduce the conductance of the pipe 17.

Next, only the visible light reflection mirror 4 is retracted out of the optical path of the soft X-rays, the gate pulp 18 is opened after the vacuum containers 5 and 13 reach a predetermined vacuum degree, and the laser light from the pulse laser 22 is opened. Is condensed on the metal target 1 by the condenser lens 24 to generate white plasma light containing soft X-rays. The generated plasma light is converged by the condenser lens 2 and illuminates the sample 25. The plasma light that has passed through the sample 25 and is diffracted is guided to the objective lens 3, is subjected to the converging action of the objective lens 3, is bent in the optical path by the visible light reflection mirror 12, and then is formed at a position conjugate with the soft X-ray detector 11. It is imaged and observed by the visible light eyepiece lens 21 with the naked eye. At this time, the antireflection film of the visible light reflection mirror 12 and the transmission prevention film of the eyepiece lens 21 cut the light of the wavelength of the laser light, and a good visible image without speckle pattern can be obtained.

In this case, since the high-power pulse laser 22 is guided by the fiber 23 just before the condenser lens 24,
The optical path of the laser light is not exposed, and it is safe, and since the laser does not have to be installed on the vibration isolation table, the vibration isolation table can be small. Further, since the lower part of the vibration isolation table is usually a space, placing the laser 22 main body here makes the entire soft X-ray microscope system compact. Further, as the detector 11, an M with a fluorescent screen that emits light with a wavelength different from that of the incident laser light
Since CP is used, it is easy to observe.

In this embodiment, the plates 6 and 14 are supported by the bottom plate end portion of the vacuum container, but if the displacement is small, the plates are supported at other positions regardless of the bottom surface, the side surface or the top surface. May be done.

Further, in the present embodiment, all the drive mechanisms such as the stage can be operated from the outside of the vacuum container, but only the necessary mechanism such as the space of the vacuum container and the optical system can be operated from the outside of the vacuum container. The other mechanism may be a conventional drive mechanism. Although the spheroidal mirror is used as the condenser lens and the Schwarzschild optical system is used as the objective lens, the present invention is not limited to this, and a Walter optical system, a zone plate optical system, or the like may be used. Further, the gate valve 18 may be directly connected to either the vacuum container 5 or the vacuum container 13.

In this embodiment, two sets of rotary pumps and turbo molecular pumps were used as the exhaust system, but one set of pumps was used as shown in FIG. 10 to open and close each valve appropriately. You may make it evacuate one vacuum container. Further, either one of the antireflection film of the visible light reflection mirror and the antireflection film of the visible light eyepiece lens may be used.

FIG. 11 shows the essential parts of the second embodiment.
In this embodiment, an X-ray reduction exposure device is used as an optical system,
A synchrotron radiation light source is used as the soft X-ray light source, and the vacuum container and the exhaust turbo molecular pump are installed on a surface plate. In the figure, 601 is a surface plate, 602 is a metal rod fixed on the surface plate 601, 603 is an O ring, and 604 is an O ring 603.
The jig that tightens the metal rod 602 and the O-ring 60
3 and the jig 604 form a part of a vacuum container 605 that holds a vacuum. A spring 606 supports the vacuum container 605. A metal plate 607 has a rigidity sufficient to hold the optical system, and is fixed to the metal rod 602. 60
Reference numeral 8 is an O-ring retainer for retaining the O-ring 603. When the jig 604 is tightened, the tightening force is transmitted to the O-ring retainer 608 and presses the O-ring 603. The pressed O-ring 603 is deformed so as to block the gap around the metal rod 602 that connects the inside and the outside of the vacuum container 605, and holds the vacuum inside the vacuum container 605. 609
Is a Schwarzschild type condenser lens, 610 is an X
A line mask, 611 is a Schwarzschild type reduction projection lens, and 612 is a wafer, and these are installed on the metal plate 607 by a stage (not shown).
Reference numeral 613 is a transparent X-ray transmission window made of beryllium. The vacuum container 605 has a small displacement rotary pump 614.
A large displacement rotary pump 615 and a turbo molecular pump 616 are connected. Reference numeral 617 is a butterfly valve.

The present embodiment is constructed as described above, and its operation is as follows. First, the small displacement rotary pump 614 is started to start exhausting the vacuum container 605. Since the rotary pump 614 has a small exhaust capacity, a violent gas flow does not occur in the vacuum container, and therefore the soft X-ray transmission window 613 is not destroyed by the impact. Even if the rotary pump 615 with a large displacement is switched to a stage where the degree of vacuum in the vacuum container reaches several torr, a violent gas flow no longer occurs inside. Further, since it does not take much time to reach this degree of vacuum, the loss of time due to the gradual evacuation by the rotary pump 614 with a small displacement is the ratio of the time taken to reach the high vacuum level at which exposure is possible. Small against.

Further, since the spring 606 absorbs the deformation of the container due to the pressure fluctuation in the vacuum container 605, the metal rod 603 is not deformed. Therefore, the metal plate 607 having the optical system fixed to the metal rod 603 is not displaced with respect to the surface plate 601 before and after the evacuation of the vacuum container 605.

In the present embodiment, the Schwarzschild optical system is used for the condenser lens and the reduction projection lens, but other soft X-ray optical system such as the Walter optical system may be used. Further, in this embodiment, the metal rod 602 is the surface plate 601.
Although the metal rod 602 is provided on the wall on which the surface plate is laid side by side, and the bottom surface of the vacuum container 605 is supported by a spring or the like that absorbs vibration, the metal is not deformed when the vacuum container 605 is deformed. The plate 607 is fixed to the wall via the metal rod 602 and is not affected by its deformation. Therefore, the condenser lens 609, the X-ray mask 610, the reduction projection lens 611, and the wafer 612, which are arranged on the metal plate 607 supported only by the metal rod 602, are also deformed in the vacuum container caused by applying a vacuum. Not affected. The same applies to the case where the metal rod 602 is other than the above-mentioned top and side attachments.

12 and 13 are a plan view and a side view of the essential parts of a third embodiment of the soft X-ray optical system according to the present invention. In this embodiment, a biological soft X-ray microscope is used as an optical system, a laser plasma light source is used as a soft X-ray light source, and a vacuum container and an exhaust turbo molecular pump are installed on a vibration isolation table. In the figure, 701 is a metal target, and 702 is a Walter type condenser lens, which constitute an illumination system for soft X-rays, and a vacuum container 703 for avoiding absorption of soft X-rays by air as much as possible. They are installed on the plate 704 placed inside by using stages 705 and 706, respectively. Then, the condenser lens 702
The soft X-rays converged by are emitted from a window 707 made of a thin film of Si ₃ N ₄ provided in a vacuum container 703, and irradiate a sample 708 placed in the air. 70
Reference numeral 9 denotes a Schwarzschild type objective lens having the same structure as the condenser lens 702, 710 is a soft X-ray detector using a CCD, and 711 is a visible light and a vacuum ultraviolet light cut arranged in front of the soft X-ray detector 710. A beryllium thin film used as a soft X-ray filter, which constitutes an enlarged image forming system for soft X-rays and is placed in a vacuum container 712 in order to avoid absorption of soft X-rays by air as much as possible. Stages 714, 715, 71 on the plate 713
6 are installed respectively. The soft X-ray transmitted and diffracted by the sample 708 is S
The light enters through the window 717 made of a thin film of i ₃ N ₄ and enters the objective lens 7
09, the soft X-ray detector 710 is made to converge. The Schwarzschild optical system constituting the objective lens 709 is coated with a Ni / Ti multilayer film having a high reflectance for soft X-rays having a wavelength in the “water window” region. Reference numeral 718 is a glass plate having a thickness of 10 μm, which is arranged by an unillustrated means in the optical path between the metal target 701 and the condenser lens 702 so as to be insertable and removable so as to be coated with a film for preventing transmission of light of the wavelength of the incident laser light.

Laser light from the high-power pulsed YAG laser 719 is guided by an optical fiber 720 to a condenser lens 721 in a vacuum container 703, and is condensed on the metal target 701 by the condenser lens 721 to generate plasma light. The end of the optical fiber 720 and the condenser lens 721 are installed on the plate 704 via a stage (not shown). These form a soft X-ray light source system. Condenser lens 7
21 and a metal target 701 are provided with a light shield plate 724 having a hole larger than the laser diameter, and between the light shield plate 724 and the condenser lens 721 is a glass plate 725 coated with an antireflection film for light of a laser wavelength. It is arranged. The light shielding plate 724 has a size sufficient to prevent at least contaminants such as electrons, ions, and neutral particles scattered from the metal target 701 from directly adhering to the glass plate 725 and the condenser lens 721 except the holes of the light shielding plate. Holding a glass plate 72
The diameter of 5 is at least large enough to prevent contaminants from the metal target 701 scattered from the holes of the light shielding plate 724 from directly adhering to the condenser lens 721.

Also in this embodiment, as in the first embodiment, the plate 704 is the end portion 7 of the bottom plate of the vacuum container 703.
03a, 703b, 703c, and 703d, the plate 713 is attached to the end portions 712a, 71 of the bottom plate of the vacuum container 712.
2b, 712c and 712d respectively support. Further, each stage can be moved from the outside of the vacuum container by using the mechanism shown in FIGS. 6 to 9.

Since this embodiment is constructed as described above, first, even if the vacuum vessels 703 and 712 are not evacuated, alignment and focusing are performed by visible light by means not shown, and then evacuated. Since the plates 704 and 705 are not displaced, the alignment will not be disturbed.

Next, the glass plate 718 is inserted into the optical path of the soft X-rays, the soft X-ray filter 711 is evacuated to the outside of the optical path of the soft X-rays, and the inside of the vacuum containers 703 and 712 reaches a predetermined vacuum degree. After that, the laser light from the pulse laser 719 is collected by the condenser lens 7
The light is condensed at 21 to generate white plasma light including soft X-rays. Laser with optical fiber 720 in vacuum chamber 703
Since it is guided inside, the optical path of the laser is not in the atmosphere and it is extremely safe. The generated plasma light is incident on the glass plate 718, but since the soft X-rays and the contaminants from the target 701 are cut off here, unnecessary soft X-rays on the sample 708 during alignment, focusing, and observation with visible light. The biological sample can be kept alive until the subsequent soft X-ray observation. Further, since contaminants from the target 701 are elastically reflected by an optical system such as a condenser, they may adhere to or destroy the X-ray transmission window 707 or the like in the subsequent stage. It is preferable to remove the contaminants scattered at the time. Further, since the glass plate 725 can be moved from the outside, even if contaminant particles adhere to the glass plate 725, a new surface can be directed to the target without releasing the vacuum.

In this embodiment, the glass plate 718 for cutting soft X-rays and contaminants is arranged between the metal target 701 and the condenser lens 702, but it may be arranged immediately after the condenser lens 702. . Although the Schwarzschild optical system is used for the condenser lens and the objective lens, the present invention is not limited to this, and the Walter optical system,
A zone plate optical system or the like may be used. Furthermore, by mounting a plurality of each optical system on the stage and exchanging it by the revolver system or the slide system by the drive mechanism used in this embodiment, it is possible to select an appropriate optical system for the observation object from the outside without opening the vacuum. .

[0040]

As described above, according to the present invention, the entire apparatus can be made compact and compact without causing misalignment of the optical system before and after the vacuum container is evacuated and exposed to the atmosphere. It is possible to provide a convenient vacuum optical system. The present invention is not limited to the soft X-ray optical system, but can be applied to all optical systems used in vacuum, such as vacuum ultraviolet light and visible light.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an alignment state of an optical system in a vacuum optical system according to the present invention when the inside of a vacuum container is in an atmospheric pressure state.

FIG. 2 is an explanatory diagram showing an alignment state of an optical system when the inside of the vacuum container shown in FIG. 1 is in a vacuum state.

FIG. 3 is a plan view of the first embodiment of the vacuum optical system according to the present invention.

FIG. 4 is a side view of FIG.

FIG. 5 is a block diagram of an example of an evacuation device used in the first embodiment.

FIG. 6 is a configuration diagram showing an example of a moving mechanism, a drive mechanism, and a power transmission mechanism that can be applied to the first embodiment.

FIG. 7 is a configuration diagram illustrating another usage state of another example of the moving mechanism and the power transmission mechanism that can be applied to the first embodiment.

8 is a configuration diagram showing another usage state of the example shown in FIG. 7. FIG.

FIG. 9 is a configuration diagram showing still another example of a moving mechanism, a drive mechanism, and a power transmission mechanism that can be applied to the first embodiment.

FIG. 10 is a block diagram of another example of the vacuum exhaust device used in the first embodiment.

FIG. 11 is a side view of a second embodiment of the vacuum optical system according to the present invention.

FIG. 12 is a plan view of a third embodiment of the vacuum optical system according to the present invention.

FIG. 13 is a side view of FIG.

FIG. 14 is an explanatory diagram showing an alignment state of an optical system when the inside of a vacuum container is in an atmospheric pressure state in a conventional vacuum optical system.

15 is an explanatory diagram showing an alignment state of the optical system when the inside of the vacuum container shown in FIG. 14 is in a vacuum state.

[Explanation of symbols]

1 ... Metal target, 2 ... Condenser lens, 3 ... Objective lens, 4 ...
..Visible light reflection mirrors, 5 ... Vacuum containers,
6 ... Plate, 7 ... Target stage,
8 ... ・ Condenser stage, 9 ・ ・ ・ Objective lens stage, 10 ・ ・ ・ ・ Reflecting mirror stage,
11 ... ・ Soft X-ray detector, 12 ・ ・ ・ ・ Visible light reflecting mirror, 13 ・ ・ ・ ・ Vacuum container, 1
4 ... Plate, 15 ... Detector stage,
16 ... ・ Reflecting mirror stage, 17 ・ ・ ・ ・ Vacuum container connecting pipe, 18 ・ ・ ・ ・ Gate valve, 19 ・ ・ ・ ・ Shading plate, 20 ・ ・ ・ ・ Visible light observation light source, 21 ・... Visible eyepiece, 22 ... High-power pulsed YAG laser, 23 ... Optical fiber
24 ... Condensing lens, 25 ... Sample,
26 ... ・ Sample stage, 27 ・ ・ ・ ・ Vibration isolation table, 28 ・ ・ ・ ・ Soft X-ray filter,
201 ... Rotary pump, 202 ... Rotary pump, 203 ... Turbo molecular pump,
204 ··· turbo molecular pump, 205 ··· conductance valve, 206 · · · conductance valve, 20
7 ... Butterfly valve, 300 ... Plate, 301 ... Vacuum container, 302 ...
Stage, 303 ... Rotation introduction terminal, 30
4 ・ ・ ・ ・ Universal joint, 305 ・ ・ ・ ・ Micrometer, 306 ・ ・ ・ ・ Rotation introduction terminal, 307 ・ ・ ・ ・
Flexible shaft, 308 ... Micrometer, 309 ... Handle, 401 ...
Vacuum container, 402 ... Plate, 40
3 ... ・ Stage, 404A, 404B ...
405 ... Fixed base, 406 ... Micrometer,
407 ... Wires 408, 409 ... Pulley,
500 ... Plate, 501 ... Vacuum container,
502 ... Stage, 503 ... Straight lead-in terminal, 504 ...
..Stage grooves, 506 ... Leaf springs, 60
1 ... Surface plate, 602 ... Metal rod,
603 ... O-ring, 604 ... O-ring tightening jig, 605 ... Vacuum container,
606 ... Spring, 607 ... Metal plate,
608 ... O-ring holder, 609 ... Condenser lens, 610 ... X-ray mask, 611 ...
..Reduction projection lens, 612 .... Wafer, 61
3 ··· Soft X-ray transmission window, 614 ··· Rotary pump, 615 ··· Rotary pump, 61
6 ... Turbo molecular pump, 617 ... Butterfly valve, 701 ... Metal target, 702 ... Condenser lens, 703 ... Vacuum container, 704
.... Plate, 705 ... Target stage, 706 ... Capacitor stage, 7
07 ・ ・ ・ ・ Soft X-ray transmission window, 708 ・ ・ ・ ・ ・ ・ Sample,
709 ... ・ Objective lens, 710 ・ ・ ・ ・ Soft X-ray detector, 711 ・ ・ ・ ・ Soft X-ray filter, 712 ・ ・
.... Vacuum vessels, 713 ... Plates, 7
14 ··· Objective lens stage, 715 ··· Detector stage, 716 ··· Filter stage, 7
17 ... Soft X-ray transmission window, 718 ... Glass plate,
719 ... High-power pulse laser, 720 ... Optical fiber, 721 ... Condensing lens, 72
2 ...- Optical fiber stage, 723-Condensing lens stage, 724-Light-shielding plate,
725 ··· Glass plate, 726 ··· Anti-vibration table

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

[Procedure amendment]

[Submission date] November 5, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

A vacuum optical system according to the present invention is a displacement which is transmitted to an optical system to be used even if a displacement of the vacuum container occurs due to the deformation of the vacuum container due to a change in atmospheric pressure in the vacuum container. An optical system mounting member, which is supported by a portion having a small displacement amount that does not exceed a predetermined variation error amount determined by the accuracy required for the optical system, is provided in the vacuum container.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

According to this vacuum optical system, the alignment of the optical system can be maintained before and after the evacuation of the vacuum container and the opening to the atmosphere. That is, for example, as shown in FIGS. 1 and 2, when an optical system is provided on a plate which is an optical system mounting member, the amount of deformation of the portion supporting the member due to the deformation of the vacuum container is required to be the accuracy required for the optical system. If it is smaller than this, the alignment accuracy of the optical system is maintained before and after the vacuum container is evacuated and opened to the atmosphere.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

As described above, according to the present invention, even if the container is deformed before and after evacuation, the alignment of the optical system in the vacuum container is not disturbed, and the moving mechanism in the vacuum container can be operated from the outside. Vacuum optics. Further, during the soft X-ray observation, the apparatus is a device that does not destroy the thin film structure such as the inside and the window of the vacuum container because the vacuum exhaust time is short.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

FIG. 9 shows a plate 50 in a vacuum container 501.
0 is a schematic view of a mechanism for operating the stage 502 fixed on the outer surface of the vacuum vessel from outside the vacuum container. The stage 502 is driven by pushing and pulling the groove portion 505 of the stage 502 with the hook 504 at the tip of the linear introduction terminal 503. . There is a play between the hint 504 and the groove 505 so that the stage 502 does not move even if the vacuum container 501 is deformed. Further, the stage 502 is set because the leaf spring 506 having the steel ball 502a attached thereto is attached to the stage 502, and the rail 508 having the section 508a cut at a right angle to the moving direction of the stage is attached to the stage attachment base 507. It is designed to reliably stop in several positions. The mechanism from FIG. 6 to FIG.
It is used in the stage of FIG. 4 depending on the position of the micrometer, the driving accuracy of the stage, and the like. Further, the vacuum container is provided with a window so that the scale of the micrometer of each stage and the position of the stage can be visually observed from the atmosphere. In the above description, the driven members such as the stage and the stage support are the moving mechanism, the members such as the handle, the rotation introducing terminal and the linear introducing terminal are the driving mechanism, and the moving mechanism and the driving mechanism such as the universal joint and the flexible shaft. The members that connect to each other to transmit power form a power transmission mechanism.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Next, only the visible light reflecting mirror 4 is retracted out of the optical path of the soft X-rays, and after the vacuum chambers 5 and 13 have reached a predetermined vacuum degree, the gate valve 18 is opened and the laser light from the pulse laser 22 is emitted. Is condensed on the metal target 1 by the condenser lens 24 to generate white plasma light containing soft X-rays. The generated plasma light is converged by the condenser lens 2 and illuminates the sample 25. The plasma light that has passed through the sample 25 and is diffracted is guided to the objective lens 3, is subjected to the converging action of the objective lens 3, is bent in the optical path by the visible light reflection mirror 12, and then is formed at a position conjugate with the soft X-ray detector 11. It is imaged and observed by the visible light eyepiece lens 21 with the naked eye. At this time, the antireflection film of the visible light reflection mirror 12 and the transmission prevention film of the eyepiece lens 21 cut the light of the wavelength of the laser light, and a good visible image without speckle pattern can be obtained.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

Since this embodiment is constructed as described above, first, even if the vacuum vessels 703 and 712 are not evacuated, alignment and focusing are performed by visible light by means not shown, and then evacuated. Since the displacements of the plates 704 and 705 are smaller than the alignment error allowable amount, the alignment will not be disturbed.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // G01J 3/02 Z 9215-2G

Claims (1)

[Claims] 1. A vacuum optical system provided with a vacuum container for storing an optical system used in a vacuum, wherein the vacuum container is displaced even if the vacuum container is displaced due to deformation of the vacuum container due to a change in atmospheric pressure in the vacuum container. At least a member on which the optical system is mounted is supported by a portion having a small displacement amount such that the displacement amount transmitted to the optical system does not exceed a predetermined variation error amount determined by the accuracy required for the optical system. A vacuum optical system, which is provided in a vacuum container.