JPH09320794A - X-ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray generator, capable of being used stably for a long time period. SOLUTION: An X-ray generator is provided with scattering particle-inhibiting member 402, (403, 404, 405, 406, and 407) for inhibiting scattering particles to be discharged from a target member 414 and/or plasma 413 from advancing into a solid angle area 412 equivalent to a range for extracting an X-ray and having shape and/or space in which the scattering particles in the solid angle area 412 are easily scattered or eliminated, by means of buffer gas adjacent to or in the vicinity of the solid angle area 412.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray
The present invention relates to an X-ray generator suitable for use in an X-ray apparatus such as an X-ray microscope and an X-ray analyzer.

[0002]

2. Description of the Related Art When a laser beam (an example of an excitation energy beam) is focused on a target member placed in a depressurized vacuum container and irradiated, the target member is rapidly turned into plasma, and the plasma emits a very bright light. It is known that high X-rays are radiated (emitted) (produce X-rays) (for example, such an X-ray source is LPX: Laser-Plasma X-raysour).
called ce).

With the generation of X-rays, high-speed scattered particles of electrons and ions from the plasma, and scattered particles of member material from the target member (for example, gasified material, ionized material, small pieces of material, etc.) ) Is released and scattered in the vacuum container (hereinafter, collectively referred to as scattered particles). Such scattered particles can form a clean optical surface (for example, X
This is a big problem because it collides with the surface of the linear optical element and damages them, or adheres and deposits to deteriorate or change the function and characteristics.

In order to solve this problem, according to the conventional method, a thin film made of a substance having a high X-ray transmission property (for example, Be) (hereinafter referred to as scattered particle blocking) is provided between the X-ray source and the cleaning optical surface. A thin film or an X-ray extraction filter) was installed and shielded to prevent scattered particles from reaching the clean optical surface. As another method, a gas having a low atomic number having a high X-ray transmittance (for example, He gas) is filled in the vacuum container, or a gas flow of the gas is formed so that the scattered particles are gasified. The molecules were made to collide with each other to prevent scattered particles (Japanese Patent Laid-Open No. 63-29255).
See 3).

When a gas is filled in the vacuum container, the particles scattered from the plasma or the target member are scattered with the gas molecules and eventually lose the energy when they are ejected.
It mixes into the movement of gas molecules. Then, it adheres to the surface or wall surface of the member in the vacuum container, or, when not only introducing the buffer gas but also exhausting it, it is exhausted together with the gas molecules by the vacuum pump.

By the way, by installing a thin film for preventing scattered particles, it is possible to prevent the scattered particles from adhering to and depositing on the clean optical surface.
Instead, flying particles adhere to the flying particle blocking thin film,
Since they are deposited, there is a problem that the X-ray transmittance of the scattered particle blocking thin film gradually decreases (the X-ray intensity used in the X-ray extraction direction decreases). In addition, X in the vacuum container
In a method of preventing scattered particles by filling a low atomic number gas (buffer gas) having a high transmittance with respect to rays or by forming a gas flow of the gas, scattered particles can be effectively prevented. There is a problem that it does not mean.

For example, when the target member is tantalum, in a sufficiently evacuated vacuum container (pressure less than 10 Pa), many scattered particles are distributed in the direction normal to the surface of the target member. When a buffer gas for preventing scattered particles is introduced into the vacuum container, in the direction where many scattered particles are emitted, the scattered particles decrease due to scattering by gas molecules, but the scattered particles are scattered before the gas introduction. The scattered particles also scatter in the direction of less emission.

Therefore, when the buffer gas is used to prevent the scattered particles, the distribution of the scattered particles in the emission direction becomes uniform. This indicates that the effect of introducing gas is smaller in the direction in which the emission of scattered particles is smaller than that in the direction in which the emission of scattered particles is large, or is rather the opposite effect. Extraction of X-rays is generally performed in the direction in which the emission of scattered particles is small, and in the X-ray extraction direction in which the emission of scattered particles is small, the effect of introducing gas may be small or may be the opposite effect. This is a big problem.

Particularly, when a scattered particle control member for controlling the directional distribution of the scattered particle emission amount near the plasma and for reducing the emitted particle emission amount in the X-ray extraction direction is provided. In regard to the X-ray extraction direction, it is a big problem that the effect of introducing gas is small, or rather has the opposite effect. Therefore, in order to solve the problem that occurs when a buffer gas is used to block scattered particles, the scattered particle blocker is placed adjacent to or close to the solid angle region through which the extracted X-rays pass so as not to block it. It has been proposed by the same applicant as the present application that the scattered particles be prevented by disposing the member (Japanese Patent Application No.
-127600).

[0010]

For example, as shown in FIG. 2, a scattered particle blocking member 202 is provided adjacent to or close to a solid angle region 212 through which X-rays to be extracted do not block. Consider a case where a buffer gas is introduced in a conventional X-ray generator. Among the scattered particles generated by the generation of the plasma 213, the particles that have jumped into the inside of the member 202 lose energy due to collision with gas molecules, drift inside the member 202, and then are blocked by being attached to the member 202. It

Here, if the time interval for generating the plasma 213 is long, the floating particles that have drifted adhere to the member 202 by diffusion before the next plasma is generated, but the plasma is long for a short time interval. When generated over time, the scattered particles inside the member 202 cannot sufficiently diffuse, so that the density of the scattered particles floating with the gas molecules inside the member 202 increases.

As a result, scattered particles reaching and adhering to the clean optical surface 240 increase, so that there is a problem that the X-ray source cannot be used stably. That is, even if the conventional scattering particle blocking member is provided adjacent to or close to the solid angle region through which the X-ray to be extracted is filled with the buffer gas in the vacuum container as described above, the plasma generation is performed at a short time interval. However, there is a problem that a sufficient effect of preventing scattered particles cannot be obtained when the temperature is extended for a long time.

The present invention has been made in view of the above problems, and is an X-ray generator that uses a buffer gas to prevent scattered particles from a plasma X-ray source, and plasma is generated at short time intervals. Extraction direction of X-rays (solid angle region through which X-rays pass) even for a long time
Or, in the passage area of the excitation energy beam, it is possible to reduce the adhesion and deposition of inconvenient flying particles (adhesion to the flying particle blocking thin film or the clean optical surface).
As a result, it is an object to provide an X-ray generator that can be used stably for a long time.

[0014]

Accordingly, the present invention first provides a method of forming a plasma by irradiating a target member in a decompressed vacuum vessel with an excitation energy beam to form a plasma,
An X-ray generator for extracting a line, the target member and / or
Alternatively, in an X-ray generator that uses a buffer gas to prevent scattered particles emitted from the plasma, a solid angle corresponding to a range in which the scattered particles emitted from the target member and / or the plasma extract the X-rays. A scattering particle blocking member which is a member for blocking entry into a region, and has a shape and / or a space in which scattered particles in the solid angle region are easily diffused and eliminated by the buffer gas,
There is provided an X-ray generator (claim 1), which is provided adjacent to or close to the solid angle region.

A second aspect of the present invention is an X-ray generator for irradiating an excitation energy beam to a target member in a vacuum container which has been decompressed to form plasma and extracting X-rays from the plasma. A member and / or an X-ray generator that uses a buffer gas to block scattered particles emitted from the plasma, wherein the member has an opening through which the excitation energy beam passes and another opening through which the X-rays pass. And a scattering particle shielding member for shielding scattering particles emitted from the target member and / or the plasma is provided in the vicinity of the target member and plasma, and the scattering particles correspond to a range for extracting the X-rays. A member that prevents entry into the solid angle region, and a shape in which scattered particles within the solid angle region are easily diffused and eliminated by the buffer gas, and Or scattering particles blocking member having a space, to provide an X-ray generator (claim 2) ", characterized in that provided by adjacent or close to the solid angle region.

A third aspect of the present invention is an X-ray generator for irradiating an excitation energy beam to a target member in a depressurized vacuum container to form plasma and extracting X-rays from the plasma. In an X-ray generator using a buffer gas to block scattered particles emitted from a member and / or the plasma, a region through which the excited energy beam passes the scattered particles emitted from the target member and / or the plasma A member for preventing entry into the inside of the area, and a flying particle blocking member having a shape and / or space in which the flying particles in the area are easily diffused and eliminated by the buffer gas are provided adjacent to or in proximity to the area. An X-ray generator (claim 3) "is provided.

A fourth aspect of the present invention is an X-ray generator for irradiating an excitation energy beam to a target member in a vacuum container, which is depressurized to form plasma, and extracting X-rays from the plasma. A member and / or an X-ray generator that uses a buffer gas to block scattered particles emitted from the plasma, wherein the member has an opening through which the excitation energy beam passes and another opening through which the X-rays pass. A target particle and / or a scattering particle shielding member for shielding the scattering particles emitted from the plasma is provided in the vicinity of the target member and the plasma, and the scattering particles are within a region through which the excitation energy beam passes. And a shape for preventing scattered particles in the region from being easily diffused and eliminated by the buffer gas and / or Scattering particles blocking member having between, X-rays generator (claim 4), characterized in that provided by adjacent or close to the region "to provide.

In a fifth aspect of the present invention, "the scattered particle blocking member has a plurality of shielding portions extending in a lateral direction or an oblique lateral direction with respect to a passing direction of the X-rays or the excitation energy beam, and the shielding portions. And a size of each opening is substantially equal to the cut surface of the solid angle region or the region through which the excitation energy beam passes, and the plurality of shielding portions and the holes are The X-ray generator according to any one of claims 1 to 4, wherein the X-ray generator is provided adjacent to or close to a region and isolated from each other in a passing direction of the X-ray or the excitation energy beam. )"I will provide a.

In a sixth aspect of the present invention, "the buffer gas is controlled to be introduced and discharged so that the pressure inside the vacuum container is within a predetermined pressure range. X-ray generator (claim 6) ".
Further, in the seventh aspect of the present invention, "a mechanism is further provided for introducing a buffer gas into the solid angle region or a region through which the excitation energy beam passes, and discharging the buffer gas together with scattered particles from within the region. An X-ray generator according to claims 1 to 6 (claim 7) "is provided.

Eighthly, the present invention relates to a "scattered particle control member for controlling the directional distribution of the amount of scattered particles emitted from the target member and / or the plasma, in the direction of extracting the X-rays. 8. A scattering particle control member for reducing the emission amount of the scattered particles, the emission amount of the scattered particles to the passage region of the excitation energy beam, or both, is further provided. An X-ray generator according to claim 8 is provided.

The ninth aspect of the present invention is that, "at least a part of the surface of the scattered particle blocking member is matt-finished, and X is defined in claim 1-8.
Line generator (claim 9) ". A tenth aspect of the present invention is that "the scattering particle blocking member is corrugated at least at a part thereof.
X-ray generator according to claim 8).

The eleventh aspect of the present invention is that "a porous material is provided on at least a part of the surface of the scattered particle blocking member, and the X according to any one of claims 1 to 8 is provided. A line generator (claim 11) ". In addition, in a twelfth aspect of the present invention, "a magnet, an electromagnet, or an electrostatic adsorber is provided in the vicinity of the solid angle region or the region through which the excitation energy beam passes, or between the scattered particle blocking member and the region. 1. The method according to claim 1, further comprising:
The X-ray generator according to claim 1 is provided.

The thirteenth aspect of the present invention is an X-ray generator according to any one of claims 1 to 12, characterized in that "cooling means for cooling the scattered particle blocking member is further provided.
3) ”.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION In an X-ray generator that uses a buffer gas to prevent scattered particles from a plasma X-ray source according to the present invention, the scattered particles fall within a solid angle region corresponding to the range for extracting X-rays. A member for preventing entry into the solid angle region, and a scattered particle blocking member having a shape and / or a space in which the scattered particles in the solid angle region are easily diffused and eliminated by the buffer gas, is adjacent to or close to the solid angle region. It is provided (claim 1).

Therefore, even when the plasma is generated for a short time at a long time, inconvenient scattering particles are attached and deposited (scattering particles are blocked) in the X-ray extraction direction (the solid angle region through which the extracted X-rays pass). Adhesion to a thin film for cleaning, a clean optical surface, etc.) can be reduced. Further, in the X-ray generator using the buffer gas for blocking the scattered particles from the plasma X-ray source of the present invention, a member having an opening through which the excitation energy beam passes and another opening through which the X-ray passes. In addition, a scattered particle shielding member that shields the scattered particles is provided in the vicinity of the target member and the plasma, and is a member that prevents the scattered particles from entering the solid angle region corresponding to the X-ray extraction range. A scattering particle blocking member having a shape and / or a space in which scattered particles in the solid angle region are easily diffused and eliminated by the buffer gas is provided adjacent to or close to the solid angle region (claim 2). ).

Therefore, even when plasma is generated for a short time and for a long time, inconvenient scattered particles are deposited or deposited (adhered to a scattered particle blocking thin film, a clean optical surface, etc.) in the X-ray extraction direction. (Deposition) can be further reduced. Further, in the X-ray generator using the buffer gas for blocking the scattered particles from the plasma X-ray source of the present invention, the member for preventing the scattered particles from entering the region through which the excitation energy beam passes. A scattered particle blocking member having a shape and / or a space in which scattered particles in the area are easily diffused and eliminated by the buffer gas is provided adjacent to or in proximity to the area (claim 3).

Therefore, even when the plasma is generated for a short period of time and for a long period of time, inconvenient scattered particles are deposited or deposited (adhesion to the scattered particle blocking thin film or the clean optical surface) in the passage region of the excitation energy beam. , Deposition) can be reduced. Further, in the X-ray generator using the buffer gas for blocking the scattered particles from the plasma X-ray source of the present invention, a member having an opening through which the excitation energy beam passes and another opening through which the X-ray passes. Is, provided a scattering particle shielding member for shielding the scattered particles in the vicinity of the target member and plasma, and a member for preventing the scattered particles from entering the region where the excitation energy beam passes, A scattered particle blocking member having a shape and / or a space in which scattered particles in the region are easily diffused and eliminated by the buffer gas is provided adjacent to or in proximity to the region (claim 4).

Therefore, even when the plasma is generated for a short period of time and for a long period of time, inconvenient scattered particles are deposited and deposited (attached to the scattering particle blocking thin film or the clean optical surface) in the passage region of the excitation energy beam. , Deposition) can be further reduced. Here, as an example of the conventional scattered particle blocking member, a member having an opening equal to (or approximately equal to) the cut surface of the solid angle region corresponding to the range for extracting X-rays is provided adjacent to or close to the region. Consider the case.

Even if such a scattered particle blocking member is provided adjacent to the solid angle region, there is no effect on the X-rays reaching the aperture equal to the cut surface of the solid angle region, and the amount of the extracted X-rays changes. do not do. On the other hand, most of the scattered particles that try to enter the solid angle region are blocked by the scattered particle blocking member, so that it is possible to reduce the inconvenient deposition and accumulation of the scattered particles in the X-ray extraction direction. it can.

The flying particle blocking member which brings about such an effect is only required to have a shape capable of blocking the flying particles from entering the solid angle region, and is not limited to a plate-shaped member having an aperture. Absent. Strictly speaking, the amount of X-ray light extracted decreases, but the above effect can be obtained even if the scattered particle blocking member is provided in the solid angle region corresponding to the range for extracting X-rays. For example, there is a case where a very thin plate is provided along the optical path on the optical path of X-rays in the solid angle region.

By the way, as described above, even if the conventional scattering particle blocking member is provided adjacent to or close to the solid angle region through which the X-ray to be extracted is filled with the buffer gas in the vacuum container and the extracted X-rays pass, When the generation is short time intervals and long time, there arises a problem that sufficient effect of preventing scattered particles cannot be obtained. Therefore, in the X-ray generator of the present invention, the scattered particles in the solid angle region or the excitation energy beam passage region are easily diffused and eliminated by the buffer gas by devising the shape and arrangement of the scattered particle blocking member. This problem is solved by providing a scattered particle blocking member having a shape and / or a space adjacent to or in proximity to the region.

That is, since the scattered particle blocking member according to the present invention has a shape and / or space in which the scattered particles in the solid angle region or the excitation energy beam passage region are easily diffused and eliminated by the buffer gas, Flying particles are effectively scattered and diffused out of the area. Most of the scattered particles that have been diffused and removed are adsorbed by the scattered particle blocking member.

Therefore, even when the plasma is generated for a short time at a long time, scattered particles are generated in the X-ray extraction direction (the solid angle region through which the extracted X-rays pass) or in the excitation energy beam passage region. Adhesion and deposition (adhesion and deposition on a scattering particle blocking thin film, a clean optical surface, etc.) can be reduced. FIG. 1 shows the arrangement of each member according to the X-ray generator (one example) of the present invention.

In the X-ray generator shown in FIG. 1, a target material (an example of a target member) 114 is placed in a vacuum container filled with gas at an appropriate pressure, and an excitation is made near the plasma 113 generation position. A scattered particle shielding member 101 which is a member having an opening through which the energy beam 111 passes and another opening through which X-rays pass, and which shields scattered particles emitted from the target material 114 and / or the plasma 113.
Is arranged.

Further, the opening (X
A space from the X-ray extraction window to the X-ray extraction window (an example of a clean optical surface) 121 is a member for preventing scattered particles from entering the solid angle region 112 corresponding to the X-ray extraction range. The scattered particle blocking member (hereinafter sometimes abbreviated as blocking member) 103, 104, 105, 106 having a shape and / or space in which the scattered particles in the solid angle region 112 are easily diffused and eliminated by the buffer gas is the solid body. The blocking members 103, 104, 105, 106 provided adjacent to or in close proximity to the corner area 112 are provided on the shield portion and the shield portion that extends long in the lateral direction or the oblique lateral direction with respect to the solid angle area 112. And the size of each opening is substantially equal to the cut surface of the solid angle region 112.

The blocking members 103, 104, 105,
106, the respective shields and apertures are in the region 112.
Are provided adjacent to or close to each other and separated from each other in the X-ray passing direction. As shown in FIG. 1, each shield extends long in the lateral direction or the oblique lateral direction with respect to the solid angle region 112, and a wide space exists between each shield.

Therefore, the blocking member 1 is removed from the plasma 113.
03 space 03, space B sandwiched by the blocking member 103 and blocking member 104, blocking member 104 and blocking member 105
Space C sandwiched by the, blocking member 105 and blocking member 10
In each of the space D sandwiched by 6 and the space E sandwiched by the blocking member 107 and the wall 122 of the vacuum container, except for each opening through which X-rays pass, scattered scattered particles hardly enter and leave.

The blocking members 103, 104, 105,
Since 106 has a shape (a long shielding portion) and a space (a wide space between the shielding portions) in which scattered particles are easily diffused and eliminated by the buffer gas, the scattered particles that have entered the solid angle region 112 are also buffer gas. Are effectively scattered by and diffused out of the solid angle region 112. Then, the scattered particles that have been diffused and eliminated are adsorbed by the elongated shielding portion of the blocking member.

Now, the effect of reducing scattered particles by the scattered particle blocking member according to the present invention will be compared with that of the conventional scattered particle blocking member. For example, a difference can be seen in the effect of reducing scattered particles between the conventional scattered particle blocking member shown in FIG. 2 and the scattered particle blocking member according to the present invention (one example) shown in FIG.

Here, a tantalum tape (thickness: 15 μm) is used as the target materials 214 and 314, krypton gas as a buffer gas is filled in a vacuum container at 0.1 Torr, and a YAG laser pulse light (λ) having an energy of 1.5 J is used.
= 1.06 μm, an example of excitation energy beam) 211, 3
11 is tantalum tape (thickness 15 μm) 214, 314
1000 times plasma 213, 313
Consider the case that occurs.

As shown in FIGS.
4, 314, the silicon wafers 240 and 340 are arranged at positions of 100 mm from the plasma 213 and 313 in an angle direction of 50 degrees from the normal direction of the surface, and the scattered particles are attached to and deposited on the surface, and the scattered particles The amount of deposition was measured by ICP mass spectrometry. In the case of the conventional scattered particle blocking member 202 shown in FIG. 2, the amount of adhesion was 30 ng, whereas in the case of the scattered particle blocking member (one example) 302 according to the present invention shown in FIG. 3, it was 7 ng. There was a difference in the amount deposited.

2 and 3, the silicon wafer 24
The adhered areas on 0 and 340 were both circular areas with a diameter of 25 mm, and the measurement was performed under exactly the same conditions except that the scattered particle blocking member was different. The deposition amount when the krypton gas was not filled was 100, which is the above value in each case.
More than doubled. As described above, it is understood that the ease of diffusion of the scattered particles diffused by the buffer gas greatly affects the effect of reducing the scattered particles.

That is, the scattering particle blocking member according to the present invention has a shape (for example, a long shielding portion) and / or a space (for example, a wide space between the shielding portions) in which the scattering particles are easily diffused and eliminated by the buffer gas. Therefore, the scattered particles that have entered the solid angle region are also effectively scattered by the buffer gas and diffused and excluded from the solid angle region. Most of the scattered particles that have been diffused and removed are adsorbed by the blocking member.

The case of the structure according to claims 1 and 2 has been described above. However, also in the case of the structure according to claims 3 and 4, similarly, the structure is arranged adjacent to or close to the region through which the excitation energy beam passes. The scattered particles that have entered the beam passage region are effectively scattered by the buffer gas and diffused and eliminated from the region by the scattered particle blocking member according to the present invention provided as above. Most of the scattered particles that have been diffused and removed are adsorbed by the blocking member.

Therefore, by disposing the scattered particle blocking member according to the present invention, a large scattering particle reducing effect can be obtained in the solid angle region or the excitation energy beam passage region even when the plasma is generated at short time intervals for a long time. As a result, the X-ray generator can be stably used for a long time. In order to increase the above-mentioned effect of reducing scattered particles, a scattered particle blocking member according to the present invention is provided with a plurality of shielding portions that extend long in a lateral direction or an oblique lateral direction with respect to the X-ray or excitation energy beam passage direction and the shielding portions. And the size of each opening is substantially equal to the cut surface of the solid angle region or the passage region of the excitation energy beam, and the plurality of shields and apertures are the regions. It is preferable that they are provided adjacent to or close to each other and separated from each other in the passage direction of the X-ray or the excitation energy beam (claim 5).

Further, in order to obtain an appropriate amount of X-rays to be taken out or to obtain an appropriate scattering particle blocking effect, the buffer gas according to the present invention has a predetermined pressure range in the vacuum container. It is preferable that the introduction and the discharge are controlled (claim 6). The buffer gas according to the present invention is preferably one that absorbs a small amount of X-rays of a wavelength to be used (taken out), and for example, X-rays to be used among gases such as helium, oxygen, nitrogen, air, argon, and krypton. It is sufficient to select a material that absorbs less.

In the X-ray generator of the present invention, a mechanism for introducing the buffer gas into the solid angle region or the region through which the excitation energy beam passes and discharging the buffer gas together with the scattered particles from the region. Is preferably provided (Claim 7). With such a configuration, by introducing the buffer gas, the scattered particles that have entered the solid angle region or the passage region of the excitation energy beam are diffused, and the buffer gas is diffused from the region to the outside together with the diffused scattered particles. Since it can be ejected, the X-ray extraction direction (solid angle region through which the X-rays pass)
Or for the passage area of the excitation energy beam,
It is possible to further reduce the adhesion and deposition of inconvenient scattered particles.

In the X-ray generator of the present invention, it is a scattered particle control member for controlling the directional distribution of the amount of scattered particles emitted from the target member and / or the plasma. A scattered particle control member for reducing the emission amount of scattered particles to a solid angle region through which the extracted X-rays pass, or the emission amount of scattered particles to the passage region of the excitation energy beam, or both of them. If provided, the effect of preventing scattered particles in each of the regions is increased, which is preferable (claim 8).

As the material used for the scattered particle control member, for example, a material having a high melting point or high hardness such as tantalum, tungsten, diamond, ceramics, stainless steel is preferable. This is because the scattered particle control member is arranged at a position very close to the plasma, so that the emission of the member material due to collision of ions and electrons flying from the plasma with the member surface is prevented. That is, when the material of the member is released, the same inconvenient adhesion and deposition as the scattered particles occur, and this is prevented.

It is preferable that at least a part of the surface of the scattered particle blocking member according to the present invention is frosted so that the scattered particles scattered can be easily adsorbed (claim 9). Similarly, in order to increase the surface area for adsorbing the dispersed flying particles, it is preferable that at least a part of the flying particle blocking member according to the present invention is corrugated (claim 10). .

Similarly, it is preferable that at least a part of the surface of the scattered particle blocking member according to the present invention is provided with a porous substance (claim 11). In the X-ray generator of the present invention, a magnet, an electromagnet, or an electrostatic adsorber may be further provided near the solid angle region or the region through which the excitation energy beam passes, or between the scattered particle blocking member and the region. When provided, the scattered particles having magnetism are adsorbed by the magnet or the electromagnet, and the scattered particles ionized by the collision with the buffer gas are adsorbed by the electrostatic adsorber, so that the scattered particle blocking effect in each of the regions is increased, which is preferable. (Claim 12).

It is preferable to further provide a cooling means for cooling the scattered particle blocking member according to the present invention, since the member easily adsorbs the scattered particles and the blocking effect is increased (claim 13). The shape of the target member according to the present invention is preferably a rollable tape shape, but may be a plate shape, a bulk shape, or a column shape. Further, the material of the target member is preferably Ta, W or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0054]

EXAMPLE FIG. 4 shows a schematic partial configuration diagram of an X-ray generator of the present example in which tape-shaped tantalum is used as a target member and X-rays around a wavelength of 14 nm are extracted and used. YAG
Laser light (an example of an excitation energy beam) 411
While being condensed by the condenser lens 452, it passes through the entrance window 423, enters the vacuum chamber 422, and is condensed on the surface of the tantalum target (an example of a target member) 414.

The tantalum target 414 has a thickness of 15 μm.
When the plasma is generated, the reel 451 is rotated by a driving means (for example, a motor, not shown) so that the laser light is not repeatedly focused on the same position on the tape. It is winding up. The movement speed of the tantalum tape is the speed at which the tape moves more than the diameter of the hole generated in the tantalum tape due to the generation of plasma from the time when one plasma is generated until the laser light for generating the next plasma is incident. Is.

YA on the tantalum tape target 414
The G laser 411 is incident and condensed at an incident angle of 45 degrees,
The X-rays generated from the generated plasma 413 are X-rays provided in the direction of 45 degrees opposite to the YAG laser 411.
The light is guided from the line extraction window (an example of a clean optical surface) 421 to the X-ray optical system. Kr gas is introduced as a buffer gas into the vacuum container 422 and is exhausted at the same time.
It is controlled to maintain a pressure of 1 Torr. Kr gas has the same transmittance as He at the same pressure for X-rays having a wavelength of 14 nm.

In the vicinity of the plasma 413, the target 4
Scattering particle shielding member 4 having openings through which the YAG laser 411 incident on 14 and the X-ray to be extracted can respectively pass.
01 is provided, and most of the scattered particles emitted from the target 414 and / or the plasma 413 are shielded by the scattered particle shielding member 401. Therefore, the amount of scattered particles diffused in the vacuum container can be reduced, and the scattered particles reaching the X-ray extraction window 421 can be reduced. In addition, it is possible to reduce contamination in the vacuum container due to scattered particles.

Further, from the vicinity of the X-ray extraction window of the shielding member 401 to the vicinity of the X-ray extraction window 421, the scattered particle blocking member 402 (constituent member) which is adjacent to or close to the solid angle region 412 corresponding to the X-ray extraction range. 403,
404, 405, 406, 407) are provided. Each component member 403, 404 of the blocking member 402,
Reference numerals 405, 406, and 407 each have a shielding portion that extends in a lateral direction or an oblique lateral direction with respect to the solid angle region 412 and an opening provided in the shielding portion, and the size of each opening is the solid angle region. 412 is approximately equal to the cut surface.

Further, each constituent member 403, 404, 40
5, 406 and 407 are provided so that their respective shields and openings are adjacent to or close to the area 412 and are separated from each other in the X-ray passing direction. As shown in FIG. 4, the constituent members 403, 404,
The shielding portions 405, 406, and 407 extend long in the lateral direction or the oblique lateral direction with respect to the solid angle region 412.

Therefore, the blocking member 402 is not shielded by the shielding member 401, and among the particles scattered in the X-ray extraction direction, the Kr particles filled in the vacuum container.
Due to scattering with gas molecules, each constituent member 403, 404,
By blocking scattered particles that cannot pass through the openings 405, 406, and 407, the amount of scattered particles reaching the X-ray extraction window 421 is reduced.

Further, each constituent member 403 of the blocking member 402 having a shielding portion extending in the lateral direction or the oblique lateral direction,
Since there are wide spaces between 404, 405, 406, and 407, respectively, the scattered particles that have entered the solid angle region 412 are also effectively scattered by the buffer gas and diffused out of the solid angle region 412. Then, most of the scattered particles that have been diffused and removed are adsorbed by the long extending shield portion of the blocking member 402.

Therefore, scattered particles reaching the X-ray extraction window 421 can be efficiently reduced. The Kr gas used as the buffer gas has a greater effect of scattering the scattered particles than a gas of an element having a small mass number such as He gas, and thus the scattered particles can be greatly reduced by the diffusion exclusion. Moreover, for X-rays with a wavelength near 14 nm, He
It has a transmittance as high as that of gas.

As a result, according to the X-ray generator of the present embodiment, the intensity of X-rays transmitted through the X-ray extraction window can be maintained for a long time and can be stably used as an X-ray source. . In this embodiment, the incident angle of the YAG laser on the surface of the target member and the X-ray extraction angle are both 45 degrees, but the angle is not limited to this angle. Although the material of the target member is tantalum, the material is not limited to this.

In the present embodiment, the shape of the target material was a tape shape, but the shape is not limited to this shape, and a plate shape, a column shape,
It may be in the form of fine particles. In this embodiment, the Kr gas pressure is set to 0.
Although it is set to 1 Torr, it is not limited to this pressure. That is, the preferable pressure varies depending on the distance from the plasma 413 to the X-ray extraction window 421, but in the case of the distance from the plasma 413 to the X-ray extraction window 421 (about 100 mm) in this embodiment, about 0.01 to 1 Torr. preferable.

In this embodiment, the Kr gas is introduced and exhausted, but if the usage time is short, the introduction and exhaust may be stopped and the pressure may be maintained. Further, the gas introduced into the container is not limited to Kr. In this embodiment, the constituent members 403, 40 in the blocking member 402 are
The space existing between 4, 405, 406, and 407 was an open shape that connects to the space inside the vacuum container at the end of each member, but after ensuring a sufficient space for scattered particles to diffuse, A blocking member 50 having a closed shape in which the space between the members does not connect to the space inside the vacuum container at the end of each member.
It may be 2 (see FIG. 5).

At this time, the gas inlet 561 may be connected to the internal space of the blocking member 502 to form a gas flow in the direction opposite to the X-ray incident direction. In this embodiment, the member 402 is not provided with a cooling mechanism, but a cooling mechanism may be further attached to enhance the adsorption effect.
In that case, it is preferable to make thermal contact with the vacuum container as small as possible.

In the present embodiment, the scattered particles are reduced by diffusing the scattered particles and adsorbing them on the surface of the member. However, as shown in FIG. (Electroadsorber) may be arranged. When the scattered particles are considered to have magnetism, a magnet or electromagnet may be arranged in the space inside the scattered particle blocking member. In this embodiment, the scattered particle blocking member is arranged for the purpose of reducing the scattered particles adhering to the X-ray extraction window, but similar members are used as the excitation energy beam introduction window for forming plasma and the window of the container. By arranging them in the vicinity, it is possible to reduce the amount of scattered particles adhering to these portions.

[0068]

As described above, according to the X-ray generator of the present invention which uses the buffer gas to prevent the scattered particles from the plasma X-ray source, the plasma is generated for a long time at short time intervals. In the case that the X-ray is taken out, the inconvenient scattering particles are adhered and accumulated (the scattering particle blocking thin film and the cleaning optics) in the X-ray extraction direction (the solid angle region through which the extracted X-rays pass) or the excitation energy beam passage region. (Adhesion to surfaces, deposition) is reduced, and as a result, the device can be used stably for a long time.

[Brief description of drawings]

FIG. 1 is a schematic partial configuration diagram showing each member of an X-ray generator (one example) of the present invention.

FIG. 2 is an experimental layout diagram during an experiment for measuring the amount of scattered particles in an X-ray generator using a conventional scattered particle blocking member.

FIG. 3 is an experimental layout diagram during an experiment for measuring the amount of scattered particles in the X-ray generator using the scattered particle blocking member according to the present invention.

FIG. 4 is a schematic partial configuration diagram of an X-ray generator according to an embodiment.

FIG. 5 is a schematic partial configuration diagram of an X-ray generator which is an example of the present invention.

FIG. 6 is a schematic partial configuration diagram of an X-ray generator which is another example of the present invention.

[Explanation of symbols]

101, 201, 301, 401, 501, 601 Scattered particle blocking member 202, 302, 402, 502, 602 Scattered particle blocking member 103, 303, 403 Scattered particle blocking member constituent member 104, 304, 404 Scattered particle blocking member Constituent members 105, 305, 405 Constituent members of scattered particle blocking member 106, 306, 406, 407 Constituent members of scattered particle blocking member 111, 211, 311, 411, 511, 611 Excitation laser light (an example of excitation energy beam) 112 , 212, 312, 412, 512, 612 Solid angle region through which X-rays to be extracted 113, 213, 313, 413, 513, 613 Plasma 114, 214, 314, 414, 514, 614 Target material (an example of target member) 121,421,521,621 X-ray Window 122, 422, 522, 622 Vacuum container 423, 523, 623 Excitation laser beam incident window 240, 340 Silicon wafer 451, 551, 651 Reel 452, 552, 652 Condensing lens 561, 661 Gas inlet 662 Electrostatic collector Dust device (or electrostatic chuck) or above

Claims (13)

[Claims] 1. An X-ray generator for irradiating an excitation energy beam to a target member in a vacuum container, which is decompressed, to form plasma, and extracting X-rays from the plasma, wherein the target member and / or the plasma In an X-ray generator that uses a buffer gas to block emitted particles, the particles emitted from the target member and / or the plasma enter into a solid angle region corresponding to a range for extracting the X-rays. Is a member for preventing the scattered particles, the scattered particles in the solid angle region has a shape and / or space that is easily diffused and eliminated by the buffer gas, and the scattered particle blocking member is adjacent to or close to the solid angle region. An X-ray generator characterized by being provided. 2. An X-ray generator for irradiating an excitation energy beam to a target member in a vacuum container that has been decompressed to form plasma, and extracting X-rays from the plasma, wherein the target member and / or the plasma An X-ray generator that uses a buffer gas to block emitted particles, which is a member having an opening through which the excitation energy beam passes and another opening through which the X-rays pass, and the target member and And / or a scattering particle shielding member for shielding scattering particles emitted from the plasma is provided in the vicinity of the target member and the plasma, and the scattering particles enter into a solid angle region corresponding to a range for extracting the X-rays. And a shape and / or a space in which the scattered particles in the solid angle region are easily diffused and eliminated by the buffer gas. The dispersed particles blocking member, X-rays generator being characterized in that disposed to be adjacent or proximate to the solid angle region. 3. An X-ray generator that irradiates an excitation energy beam to a target member in a vacuum container that has been decompressed to form plasma, and takes out X-rays from the plasma, wherein the target member and / or the plasma. In an X-ray generator that uses a buffer gas to block emitted particles, the particles emitted from the target member and / or the plasma are prevented from entering an area through which the excitation energy beam passes. And a scattering particle blocking member having a shape and / or a space in which scattered particles in the region are easily diffused and eliminated by the buffer gas, which is provided adjacent to or in proximity to the region.
Line generator. 4. An X-ray generator for irradiating an excitation energy beam to a target member in a vacuum container, which has been decompressed, to form plasma, and extracting X-rays from the plasma. The target member and / or the plasma An X-ray generator that uses a buffer gas to prevent emitted scattered particles, which is a member having an opening through which the excitation energy beam passes and another opening through which the X-rays pass, and the target member and And / or a scattering particle shielding member for shielding scattering particles emitted from the plasma is provided in the vicinity of the target member and the plasma, and the scattering particles are prevented from entering the region through which the excitation energy beam passes. Particles that are members and have a shape and / or a space in which scattered particles in the region are easily diffused and eliminated by the buffer gas. The stop member, X-rays generator being characterized in that disposed to be adjacent or in proximity to the region. 5. The scattered particle blocking member includes a plurality of shield portions extending in a lateral direction or an oblique lateral direction with respect to a passing direction of the X-rays or the excitation energy beam, and holes provided in each of the shield portions. And the size of each aperture is substantially equal to the cut surface of the solid angle region or the region through which the excitation energy beam passes, and the plurality of shields and apertures are adjacent or close to the region, And the above X
Lines or the direction of passage of the excitation energy beam, which are isolated from each other.
4. The X-ray generator according to 4. 6. The X-ray generator according to claim 1, wherein the buffer gas is controlled so as to be introduced and discharged so that the inside of the vacuum container has a predetermined pressure range. 7. A buffer gas is introduced into the solid angle region or a region through which the excitation energy beam passes,
Further, a mechanism for discharging the buffer gas together with the scattered particles from the area is further provided.
The X-ray generator according to item 6. 8. A scattered particle control member for controlling the directional distribution of the amount of scattered particles emitted from the target member and / or the plasma, wherein the amount of scattered particles emitted in the X-ray extraction direction is Alternatively, the X-ray generator according to any one of claims 1 to 7, further comprising a scattered particle control member for reducing the emission amount of the scattered particles to the passage region of the excitation energy beam or both of them. 9. The X-ray generator according to claim 1, wherein at least a part of the surface of the scattered particle blocking member is matt processed. 10. The X-ray generator according to claim 1, wherein at least a part of the scattered particle blocking member is corrugated. 11. The X-ray generator according to claim 1, wherein a porous material is provided on at least a part of the surface of the scattered particle blocking member. 12. A magnet, an electromagnet, or an electrostatic adsorption device is further provided near the solid angle region or the region through which the excitation energy beam passes, or between the scattered particle blocking member and the region. Claim 1 characterized by
11. The X-ray generator according to item 11. 13. The X-ray generator according to claim 1, further comprising cooling means for cooling the scattered particle blocking member.