JP2768545B2 - X-ray light source device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an X-ray light source device.

[Conventional technology]

In recent years, research has been conducted on a laser plasma light source as a soft X-ray light source of a laboratory specification.

 The principle of this laser plasma light source is as follows.

First, a laser beam is incident from the atmosphere through a transparent window into a vacuum vessel, and is irradiated on a target placed in the vacuum vessel. Then, high-temperature, high-density plasma is generated from the target, and soft X-rays are radiated therefrom.

[Problems to be solved by the invention]

However, when high temperature and high density plasma is generated,
Contaminants (debris) such as target fragments are scattered and try to adhere to the inner wall of the vacuum vessel. In this type of apparatus, an ionization vacuum gauge or the like is provided so as to communicate with the inside of the vacuum vessel through an opening provided with the wall surface of the vacuum vessel for measuring a relatively high vacuum. However, in most vacuum gauges, the detection part is generally 10 to 20 in diameter.
It is built into a glass tube with a conduit of about mm, and if contaminants enter the glass tube and adhere to it, there is a problem that the vacuum gauge will not function properly and accurate vacuum measurement will not be possible. Was.

The present invention has been made in view of the above problems, and provides an X-ray light source device capable of preventing a contaminant flying from a target from adhering to a vacuum gauge and performing accurate vacuum measurement for a long time. It is an object.

[Means for solving the problem]

The X-ray light source device according to the present invention is provided with a vacuum gauge that communicates with the inside of the vacuum vessel through an opening provided on a wall surface of the vacuum vessel, and irradiates a target disposed inside the vacuum vessel with laser light. An X-ray light source device configured to extract X-rays generated from plasma generated by a laser beam, wherein the opening is not directly visible from the irradiation position of the laser beam on the target at a position close to the opening in the vacuum vessel. A shielding member is provided.

Further, another one of the X-ray light source devices according to the present invention is such that the vacuum gauge is connected to the opening through a communication path, and an entrance of the vacuum gauge is directly visible from a laser light irradiation position on the target. It is characterized in that the communication path is curved so as not to occur.

Still another aspect of the X-ray light source device according to the present invention is characterized in that the opening is provided at a position that is not directly visible from a laser light irradiation position on the target.

(Operation)

In any of the above configurations, the entrance of the vacuum gauge is not directly visible from the laser light irradiation position on the target that is a source of contaminants, so that the vacuum gauge flies straight from the laser light irradiation position on the target. The amount of incoming contaminants deposited in the gauge is greatly reduced.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a schematic view of an X-ray sample inspection apparatus including a first embodiment of an X-ray light source device according to the present invention, and 1 is a vibration isolation table that supports components while damping vibration.

Reference numeral 2 denotes a cylindrical vacuum vessel installed on the vibration isolation table 1, which has a circular transparent window 3 made of glass and openings 4 and 5, and a target made of a metal material such as gold inside. 6 is provided so as to be rotatable around an axis 7, and a circular transparent shielding plate 8 made of glass having substantially the same size as the window 3 is provided at a position close to the internal transparent window 3. . or,
A vacuum gauge 37 communicating with the inside of the vacuum vessel 2 through an opening 36 provided on the wall surface of the vacuum vessel 2 is attached to the outer surface of the vacuum vessel 2. 9 is mainly Nd: YAG installed on the vibration isolation table 1
A high-power pulse laser light source such as 10; a condensing lens 10 for condensing laser light; the laser light from the pulse laser light source 9 is condensed by the condensing lens 10 to the target 6 through the transparent window 3 and the shielding plate 8. Upon irradiation, a part of the target 6 is melted, evaporated and turned into plasma, and soft X-rays are generated from the high-temperature and high-density plasma. At this time, the shielding plate 8 prevents the scattered contaminants from being deposited on the transparent window 3. The transparent window 3 and the shielding plate 8 are positioned with respect to the optical axes of the laser light source 9 and the condenser lens 10 so that the reflected light of the laser light does not return to the laser light source 9 to make the oscillation of the laser light unstable. The target 6 is installed at an angle of about 3 ° and an anti-reflection film is provided so that the target 6 can be efficiently irradiated with laser light. The above members constitute the X-ray light source device 11.

Reference numeral 12 denotes another vacuum vessel which is installed on the vibration isolation table 1 and connected to the vacuum vessel 2 through the opening 4 and has openings 13 and 14 and has an entrance slit 15 and oblique incidence inside. A diffraction grating (concave diffraction grating) 16 is provided. The above members constitute the spectroscope 21.

Reference numeral 17 denotes a telescopic bellows having one end connected to the vacuum container 12 through the opening 13, 18 denotes another vacuum container connected to the other end of the bellows 17, and the vacuum container 18 is, for example, a bellows 17. The diffraction grating 16 is mounted on the vibration isolation table 1 via a pedestal 19 which is movable along the circumference of the Rowland circle of the diffraction grating 16 by being movable in both the longitudinal direction and the lateral direction. Reference numeral 20 denotes an exit slit which is provided in the vacuum vessel 18 at a position coinciding with the pedestal 19, that is, moves on the Rowland circle of the diffraction grating 16 as the pedestal 19 moves. Reference numeral 22 denotes a sample stage rotatably installed in the vacuum vessel 18, and reference numeral 23 denotes a first channel such as a channeltron installed rotatably around the sample stage 22 in the vacuum vessel 18.
In this soft X-ray detector, the center of the diffraction grating 16, the center of the exit slit 20, and the center of the sample stage 22 are always located on a straight line. The above-described members constitute the measuring unit 27.

Reference numeral 24 denotes a second soft X-ray detector which is installed in the vacuum vessel 2 and monitors the intensity of soft X-rays in the X-ray light source device 11. 25 is a first soft X-ray detector 23 and a second soft X-ray detector
A computer that performs arithmetic processing based on an output signal from 24 according to a predetermined formula, and displays the result on a display device 26. The computer 25 controls the oscillation of the pulse laser light source 9, the rotation of the target 6, the movement of the pedestal 19, the rotation of the sample stage 22, and the rotation of the soft X-ray detector 23.

Numeral 28 denotes a magnetically levitated turbo molecular pump having one end connected to the vacuum vessel 2 through the opening 5 and installed on the vibration isolation table 1, and 29 denotes a rubber tube hardly transmitting vibration.
Rotary pumps for rough evacuation which are connected to the other end of the turbo molecular pump 28 via the base 30 and are installed outside the vibration isolator 1, and these vacuum pumps perform evacuation in the vacuum vessel 2. The unit 31 is constituted.

Reference numeral 32 denotes a magnetically levitated turbo-molecular pump that is connected to the vacuum vessel 12 at one end through the opening 14 and is installed on the vibration isolation table 1. Reference numeral 33 denotes a turbo-molecular pump through a rubber tube 34.
Rotary pumps for roughing, which are connected to the other end of the vacuum chamber 32 and installed outside the vibration isolation table 1,
A vacuum pump unit 35 for evacuating the inside, the inside of the bellows 17 and the inside of the vacuum vessel 18 is configured.

FIG. 2 is a schematic perspective view showing a mounting structure of the vacuum gauge 37 of this embodiment, and FIG. 3 is an enlarged view of a main part of FIG.

Numeral 38 is a shielding plate provided at a position close to the opening 36 in the vacuum vessel 2, and its size is drawn from the irradiation position P of the laser beam on the target 6 so as to be in contact with the edge of the shielding plate 38. The size is selected so that the straight line 1 does not cover the opening 36, that is, the opening 36 cannot be seen from the position P because the shadow of the shielding plate 38 covers the opening 36.

Since the present embodiment is configured as described above, when the pulse laser light source 9 is oscillated to irradiate the target 6 with laser light, a part of the target 6 is melted and evaporated to form plasma, and the soft X-ray 41 occurs. When a part of the target 6 evaporates and becomes concave, the target 6 is rotated so that the laser light is irradiated on a new surface. The generated soft X-ray 41 is guided to the entrance slit 15 through the opening 4 of the vacuum vessel 2, enters the diffraction grating 16 through the entrance slit 15, and is separated. Soft X-rays 42 separated by the diffraction grating 16
Is incident on the sample S on the sample stage 22 through the exit slit 20, and the soft X-ray 43 diffracted by the sample S is detected by the soft X-ray detector 23. In this case, only the soft X-rays 42 of a specific wavelength determined according to the positional relationship between the entrance slit 15, the diffraction grating 16 and the exit slit 20 are emitted from the exit slit 20, so that the movement of the base 19 causes the exit slit 20 to move. Is moved, the wavelength of the soft X-ray 42 passing through the exit slit 20 changes, that is, wavelength scanning is performed. Therefore, since the wavelength of the soft X-rays 42 incident on the sample S changes, the spectral reflectance of the sample S can be measured. By rotating the sample stage 22, the incident angle of the soft X-rays 42 on the sample S can be set arbitrarily. Further, by rotating the soft X-ray detector 23 around the sample stage 22, the soft X-ray 43 from the sample S can be detected at an arbitrary diffraction angle.

Thus, the sample is inspected by X-rays,
When a line is generated, contaminants scatter from the target 6 and try to adhere to the inner surface of the vacuum vessel 2. However, since the opening 36 is covered with the shielding plate 38, contaminants flying straight from the irradiation position P of the laser beam on the target 6 can be measured by the vacuum gauge.
No longer gets inside 37. Therefore, since the dirt in the vacuum gauge 37 is reduced, accurate vacuum measurement can be performed for a long time.

Some of the evaporated contaminants float in the vacuum vessel 2, but those that cause dirt in the vacuum gauge 37 fly straight but have a high weight. Is enough. In order to prevent contamination by floating objects, it is better to bring the shielding plate 38 as close as possible to the opening 36. However, if it is too close, the communication between the vacuum gauge 37 and the vacuum vessel 2 will be too low, and the measurement accuracy will decrease. Therefore, it is necessary to leave a certain gap or more.

FIG. 4 is an enlarged view of a main part of a modification of the first embodiment,
The shielding member 39 is formed by arranging a plurality of strip-shaped plates at an angle so that no gap is formed between the adjacent plates in the direction in which the contaminants fly. It is configured such that there is a gap between the plate and the plate. Therefore, it is preferable because the gap between the plates facilitates the flow to the vacuum gauge.

FIG. 5 is an enlarged view of a main part of the second embodiment, in which a vacuum gauge 37 is connected to an opening 36 through a communication path 40, and a connection path 40 from the laser beam irradiation position P on the target 6. The communication path 40 is curved so that a straight line 1 connecting the edges of the inlet of the vacuum gauge 37 does not extend to the inlet of the vacuum gauge 37, that is, the inlet of the vacuum gauge 37 is not directly visible from the position P.

In the case of the present embodiment, since the degree of protrusion of the vacuum gauge 37 from the vacuum vessel 2 to the outside is reduced, the probability of colliding with and breaking the vacuum gauge when working around it is preferable.

FIG. 6 is an enlarged view of a main part of the third embodiment.
Alternatively, the opening 36 is provided at a position where it deviates toward the back side of the target 6 from a line 1 drawn so as to be in contact with a support member having a larger protrusion, that is, at a position not directly visible from the point P. It is preferable that the opening 36 is as far as possible from the region where the contaminant flies, so that it is preferable that the opening 36 be located as far as possible from the line 1 in angle.

In this embodiment, since the position of the opening 36 is simply selected, the configuration is the simplest.

〔The invention's effect〕

As described above, the X-ray light source device according to the present invention has an important practical advantage that a contaminant flying from a target is prevented from adhering to the inside of a vacuum gauge, and accurate vacuum measurement can be performed for a long time. doing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an X-ray sample inspection apparatus including a first embodiment of an X-ray light source device according to the present invention, FIG. 2 is a diagram showing a mounting structure of a vacuum gauge of the first embodiment, and FIG. FIG. 2 is an enlarged view of a main part of FIG. 2, FIG. 4 is an enlarged view of a main part of a modification of the first embodiment,
FIGS. 5 and 6 are enlarged views of the main parts of the second and third embodiments, respectively. 2 ... Vacuum container, 3 ... Transparent window, 4,5,36 ... Opening, 6 ...
... Target, 7 ... Axis, 8 ... Shielding plate, 9 ... High-power pulse laser light source, 10 ... Condensing lens, 11 ... X-ray light source device, 31 ... Vacuum pump unit, 37 ... Vacuum gauge , 38 ... shielding plate, 339 ... shielding member, 40 ... communicating passage.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikoko Kato 2-34-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (72) Inventor Keiki Iketaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olin (58) Field surveyed (Int.Cl. ⁶ , DB name) H05G 1/00

Claims (3)

(57) [Claims] A vacuum gauge communicating with the inside of the vacuum vessel through an opening provided on a wall surface of the vacuum vessel, and a plasma generated by irradiating a target disposed inside the vacuum vessel with laser light. An X-ray light source device configured to extract X-rays generated from a target, a shielding member having a size such that the opening is not directly visible from a laser light irradiation position on the target at a position close to the opening in the vacuum container. An X-ray light source device comprising: 2. A plasma generated by irradiating a laser beam to a target disposed inside the vacuum vessel, wherein a vacuum gauge communicating with the inside of the vacuum vessel is provided through an opening provided in a wall surface of the vacuum vessel. An X-ray light source device configured to extract X-rays generated from the target, wherein the vacuum gauge is connected to the opening via a communication path, and an entrance of the vacuum measurement device is directly connected to a laser beam irradiation position on the target. An X-ray light source device wherein the communication path is curved so as not to be seen. A vacuum gauge communicating with the inside of the vacuum vessel through an opening provided on a wall surface of the vacuum vessel; and a plasma generated by irradiating a target disposed inside the vacuum vessel with a laser beam. An X-ray light source device configured to extract X-rays generated from a target, wherein the opening is provided at a position that is not directly visible from a laser light irradiation position on the target.