JPH07167997A - X-ray radiation device - Google Patents

Abstract

PURPOSE:To allow high intensity X-rays to be radiated uniformly to an irradiated object. CONSTITUTION:An X-ray radiation device is provided with a converging mirror of which the reflecting surface is the inner peripheral surface Fi of the rotating curved surface obtained by rotating a line segment Ls, formed of part of a parabola Pr, around an axis A passing the focus (f) of the parabola Pr and inclined onto the line segment Ls side in relation to the main axis X of the parabola Pr. X-rays Lx are radiated toward the inner peripheral surface of the converging mirror from the position of the focus (f).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for irradiating an observation sample with X-rays in an X-ray microscope, or for irradiating a reticle with X-rays in an X-ray projection exposure apparatus.
The present invention relates to a radiation irradiation device.

[0002]

2. Description of the Related Art In observing a sample with an X-ray microscope, X-rays with a laser plasma as shown in FIG.
A line irradiation device is used. This X-ray irradiation device condenses laser light L from a laser oscillator (not shown) with a condensing lens 60 and irradiates a target 62 in a vacuum container 61 with a spot through a laser light introduction window 65 to form a target. A plasma P having a diameter of about 100 μm is generated on the surface of 62, and the X-ray Lx emitted from the plasma P through the visible light removing filter 63 is emitted from the spheroidal mirror 64 having an X-ray reflection multilayer film formed on the surface thereof. Collected by
To irradiate.

In irradiating a reticle or the like with an X-ray by an X-ray projection exposure apparatus, for example, as shown in FIG. From the diffracted light Ld of 1, the mixed light such as the high-order diffracted component of the short wavelength light and the visible light is removed by the filter 71, and the reticle R is irradiated with the monochromatic X-ray Lx.

[0004]

However, in any of the above-described conventional X-ray irradiators, the observation sample M and the reticle R are irradiated with X-rays by using the spheroidal mirror 64 and the diffraction grating spectroscope 70. Therefore, the X-ray source (plasma P,
The X-ray intensity distribution in the synchrotron) is reflected as the illuminance distribution on the irradiated object, and if the X-ray intensity distribution of the light source is not uniform, uneven illumination occurs. That is, since the X-rays emitted by the spheroidal mirror 64 and the diffraction grating spectroscope 70 are, so to speak, an image of the X-ray source, the intensity unevenness of the X-ray source is the same as the illumination unevenness on the observation sample M or the reticle R. Become.

If a concave mirror having a rotating parabolic surface is used as the reflecting mirror, all light rays emitted from the focal point of the concave mirror will be light rays parallel to the central axis of the rotating parabolic surface (main axis of the parabola), and parallel light will be obtained. The uneven lighting is eliminated. However, the concave mirror having a rotating parabolic surface does not have the ability to collect light, and the intensity of X-rays that irradiate the observation sample, reticle, etc. cannot be increased.

An object of the present invention is to provide an X-ray irradiating device capable of uniformly irradiating an irradiated object with high-intensity X-rays.

[0007]

1 to 5 showing an embodiment, the invention of claim 1 defines a line segment Ls formed by a part of a parabola Pr as a focal point of the parabola Pr. f
A condenser mirror 1 having a reflecting surface 3 which is an inner peripheral surface of a rotating curved surface obtained by rotating around an axis A which passes through and which is inclined toward the line segment Ls side with respect to the main axis X of the parabola Pr, The above-described object is achieved by configuring the X-ray irradiation device that emits the X-ray Lx from the position toward the inner peripheral surface of the condenser mirror 1 (see FIGS. 1 to 3).

Further, in the invention of claim ₂ , each of a plurality of line segments Ls ₁ and Ls ₂ formed by a part of each of a plurality of different parabolas Pr ₁ and Pr ₂ sharing one focus f A parabola P passing through f and corresponding to each of the line segments Ls ₁ and Ls _2.
reflecting each of the inner circumferential surface of the plurality of rotating curved surface obtained by rotating around the r _1, of the Pr ₂ spindle X _1, line Ls ₁ relative to X _2, Ls ₂ one axis which is inclined side A The above-mentioned object is achieved by constructing an X-ray irradiator that includes the condenser mirror 1 having the surfaces 3 ₁ and 3 ₂ and radiates the X-ray Lx from the position of the focus f toward the inner peripheral surface of the condenser mirror 1. Achieved (see Figures 4 and 5). Focus f
The point X-ray source 2 may be arranged at the position of, and the X-ray reflection multilayer film 4 may be provided on the reflecting surface of the condenser mirror 1.

[0009]

The X-ray Lx emitted from the focus position F is reflected by the reflecting surface 3 of the condenser mirror 1, and the reflected X-ray Lx is a path p parallel to the main axes X and X'of the parabolas Pr and Pr, Proceed with p '. The reflecting surface 3 of the condenser mirror 1 of the present invention is
It is formed in an annular shape around the axis A. Therefore, the X-ray Lx reflected from the entire reflecting surface 3 has an inclination angle a of 2 with respect to the parabolic main axis X of the axis A forming the center of rotation of the condenser mirror 1.
The light is focused in a region C centered on the axis A with a double focusing angle b.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.

[0011]

【Example】

-First Embodiment- Fig. 1 is a sectional view showing a first embodiment of the X-ray irradiation apparatus according to the present invention, and Fig. 2 is a perspective view. As shown in these figures,
The X-ray irradiation apparatus of this embodiment includes a condenser mirror 1 and a micro X-ray source 2.

The condensing mirror 1 has a substantially annular outer shape, and its inner peripheral surface is a reflecting surface 3. As shown in FIG. 3, the reflecting surface 3 passes a line segment Ls formed by a part of the parabola Pr through a focal point f of the parabola Pr, and a line segment Ls of the main axis (symmetry axis) X of the parabola Pr. It is composed of an inner peripheral surface Fi of a curved surface obtained by making one rotation about the axis A inclined to the side. In FIG. 3, reference numeral Pr ′ represents a state in which the parabola Pr is rotated by 180 ° around the axis A, and reference numeral Ls ′ represents the line segment L.
It shows a state in which s is rotated about the axis A by 180 °, and the symbol X'denotes the main axis of the parabola Pr '. It should be noted that, by rotating the line segment Ls around the axis A, the corresponding parabola Pr and its principal axis X are also rotated around the axis A, and any of the reflecting surfaces 3 can be rotated. The directions of the corresponding main axes X at the circumferential positions are different from each other. As will be described later, the direction of the main axis X determines the X-ray irradiation direction and area.

An X-ray reflection multilayer film 4 is formed on the front surface of the reflecting surface 3 of the condenser mirror 1. The X-ray reflection multilayer film 4 has a structure in which a substance having a large difference between the refractive index in X-rays of a certain wavelength and a vacuum (= 1) and a substance having a small difference are alternately laminated. By satisfying the conditional expression (1), X-rays having a specific wavelength are reflected. Due to the X-ray reflection multilayer film 4, the entire reflection surface 3 is X-ray.
It has a uniform reflectance for the line. The wavelength of the X-rays selectively reflected by the X-ray reflective multilayer film 4 depends on the material and the cycle length of each layer constituting the multilayer film 4 (the film thickness of one pair of the material having the large difference and the material having the small difference). These are determined by a known method (typically, a combination of tungsten (W) and carbon (C) is known). The material forming each layer is formed by a thin film forming technique such as vacuum deposition. Small X
The radiation source 2 is arranged at a focus position F that matches the focus f of the parabola Pr, and radiates the X-ray Lx toward the reflecting surface 3 of the condenser mirror 1.

The X-ray Lx emitted by the minute X-ray source 2 arranged at the focal point F is reflected by the reflecting surface 3 of the condenser mirror 1. When the reflection of the X-rays by the reflecting surface 3 is described in detail with reference to FIG. 3, the X-rays incident on the line segment Ls in FIG.
It traverses the axis A with a path p parallel to the main axis X of the parabola Pr. On the other hand, the X-ray Lx incident on the line segment Ls ′ located at a position 180 ° away from the line segment Ls is the main axis X of the parabola Pr ′.
Cross the axis A with a path p'parallel to '. Similarly, when the X-ray path is traced for the entire reflecting surface 3, the X-ray Lx emitted from the minute X-ray source 2 is reflected by the reflecting surface 3 of the condenser mirror 1 as shown in FIG. Focusing angle b that is twice the tilt angle a of the axis A of the condenser mirror 1 with respect to the parabolic main axis X (see FIG. 1,
(See FIG. 3) A small circular area C centered on the axis A
Focus inside.

Therefore, as shown in FIG. 1, by arranging the irradiated object M in this minute circular region C, the entire irradiated object M is uniformly irradiated by the focused and parallel X-rays Lx. be able to.

When the reflecting surface 3 of the condenser mirror 1 is not coated with the X-ray reflection multilayer film 4, total reflection due to oblique incidence of X-rays is utilized, so that spectroscopy cannot be performed. In addition, the focal length becomes large. On the other hand, if the reflecting surface 3 is coated with the X-ray reflective multilayer film 4, the reflection angle of the X-rays on the reflecting surface 3 can be set to a large value, the focal length becomes short, and the entire apparatus becomes compact. Further, as described above, it becomes possible to irradiate the irradiated object M with an arbitrary monochromatic X-ray by selecting the multilayer film material and the layer thickness of the X-ray reflective multilayer film 4.

-Second Embodiment- FIG. 4 is a view showing a second embodiment of the X-ray irradiation apparatus according to the present invention. In FIG. 4, the same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be simplified.

In this embodiment, the condenser mirror 1 is provided with a plurality (more specifically, two) of reflecting surfaces 3 ₁ and 3 ₂ and is formed as a barrel-shaped hollow annular body as a whole. These reflecting surfaces 3 ₁ and 3 ₂ have two line segments L formed by a part of each of _two different parabolas Pr ₁ and Pr ₂ sharing one focal point f.
Each of s ₁ and Ls ₂ passes through the focal point f and each line segment L
principal axes X _{1 of} parabolas Pr ₁ and Pr ₂ corresponding to s ₁ and Ls ₂ ,
It is composed of a plurality of inner circumferential surfaces Fi ₁ and Fi ₂ of a rotating curved surface obtained by making one rotation around one axis A inclined toward the line segments Ls ₁ and Ls ₂ with respect to X ₂ .

The reflecting surface 3 ₁ of the collector mirror 1, 3 to ₂ X-ray reflection multilayered film 4 is coated over its entire surface, the whole of the reflecting surface 3 _1, 3 ₂ to the X-ray having a specific wavelength It is configured to have a uniform reflectance. In this case, since the line segments Ls ₁ and Ls ₂ are continuous in the axial direction, the reflecting surfaces 3 ₁ and 3 ₂ of the condenser mirror 1 are continuous in the axial direction.

The focal position F on the arranged small X-ray source 2 is an X-ray Lx emitted is reflected by each reflecting surface 3 _1, 3 ₂ of the collector mirror 1, each reflecting surface 3 _1, 3 ₂ Reflected X-ray Lx
Is a parabola Pr ₁ corresponding to each of the reflecting surfaces 3 ₁ , 3 _2.
Alternatively, it has the paths p ₁ and p ₂ parallel to the principal axes X ₁ and X ₂ of Pr, and the focusing angle is twice the tilt angles a ₁ and a ₂ with respect to the parabolic principal axes X ₁ and X ₂ of the axis A of the condenser mirror 1. b _1, b overlap collecting light into a small circular area C _{where 2} about the axis a with.

Therefore, also in this embodiment, by arranging the irradiated object M in the minute circular region C, it is possible to uniformly irradiate the entire irradiated object M with the focused and parallel X-rays Lx. it can. Moreover, in this embodiment, since the X-rays Lx from the reflecting surfaces 3 ₁ and 3 ₂ are condensed in the minute circular region C, the X-rays L radiated to the irradiation target M are irradiated.
The intensity of x doubles.

A method of determining the reflecting surfaces 3 ₁ and 3 ₂ will be described with reference to FIG. (1) First, consider a line segment Ls ₁ that has a focal point f at a position shown in the figure and forms a part of a parabola Pr ₁ whose principal axis is a straight line X ₁ passing through the focal point f. The X-ray Lx emitted from the X-ray source arranged at the focal point position F that matches the focal point f has a line segment Ls _{1 on the} inner peripheral surface.
The optical path p ₁ parallel to the principal axis X ₁ is reflected by the reflecting surface corresponding to
Follow. (2) Next, have a common focus and the focus f of the parabola Pr ₁ in the position shown, the parabola Pr ₁ different parabola Pr ₂ to the main axis of the straight line X ₁ is different from a straight line X ₂ passing through the focal point f one Consider a line segment Ls ₂ forming a part. The X-ray Lx emitted from the X-ray source arranged at the focal position F matching the focal point f is reflected by the reflecting surface whose inner peripheral surface coincides with the line segment Ls _2, and the optical path p ₂ parallel to the main axis X ₂ is obtained. Follow. (3) The optical path p ₁ and the optical path p ₂ intersect at the area C shown in the figure. (4) as a rotation axis line A passing through the the intersection region C the center point and the above-described focal point f of the rotary curved surface by rotating the line segment Ls _1, Ls ₂ forming part of a parabola Pr _1, Pr ₂ Form.
The inner peripheral surface of this rotating curved surface becomes the reflecting surfaces 3 ₁ , 3 _{2 of the} condenser mirror 1.

-Third Embodiment- In the embodiment shown in FIG. 4, the reflecting surfaces 3 ₁ and 3 ₂ of the condenser mirror 1 are continuous with each other in the axial direction, but as shown in FIG. In addition, they may be configured differently in diameter and arranged concentrically with each other about the axis A. Also in this case, the X-rays Lx are converged in the minute circular region C in an overlapping manner with the path shown in the figure, so that the same effect as that of the second embodiment can be obtained.

In the first to third embodiments described above, X
When the radiation source 2 also emits visible light, it is between the X-ray source 2 and the reflecting mirror 1, or between the reflecting mirror 1 and the illuminated object M.
It is desirable to dispose a filter for removing visible light between and.

The details of the X-ray irradiator of the present invention are not limited to the above-mentioned embodiments, and various modifications are possible.

[0026]

As described above in detail, according to the present invention, the X-rays reflected by the reflecting surface of the condenser mirror travel parallel to the main axis of the parabola forming the reflecting surface, and , Is focused on the area in the extension direction of the rotation axis of the reflecting surface,
By arranging the irradiation target object in this area, it becomes possible to uniformly collect and irradiate the irradiation target object with a uniform illuminance distribution. Further, according to the invention of claim 2, since the condenser mirror has a plurality of reflecting surfaces, the intensity of the X-rays irradiated to the irradiation target object increases according to the total area of the reflecting surfaces,
Illuminance increases. The number of the reflecting surfaces arranged may be any number as long as the three-dimensional arrangement allows. Further, according to the invention of claim 4, since the X-ray reflection multilayer film is formed on the reflecting surface,
The X-ray reflection angle on the reflecting surface can be set large and the focal length can be shortened, so that the apparatus can be made compact.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an X-ray irradiation device according to a first embodiment of the present invention.

FIG. 2 is a schematic perspective view of the X-ray irradiation apparatus according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a geometrical shape of a condenser mirror used in the X-ray irradiation apparatus according to the first embodiment.

FIG. 4 is a vertical sectional view showing an X-ray irradiator according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view showing an X-ray irradiator according to a third embodiment of the present invention.

FIG. 6 is a diagram for explaining a method of determining a reflecting surface of the X-ray irradiating device of the second embodiment.

FIG. 7 is a schematic configuration diagram showing a conventional example of an X-ray irradiation device used in an X-ray microscope.

FIG. 8 is a schematic configuration diagram showing a conventional example of an X-ray projection exposure apparatus.

[Explanation of symbols]

1 Focusing mirror 2 Micro X-ray source Pr, Pr ₁ , Pr ₂ Parabola f Focus F Focus position A Axis X, X ₁ , X ₂ Main axis

Claims (4)

[Claims] 1. An inner circumference of a curved surface obtained by rotating a line segment formed by a part of a parabola around an axis passing through a focal point of the parabola and inclined to the main axis of the parabola toward the line segment side. An X-ray irradiator that includes a condenser mirror having a surface as a reflection surface, and emits X-rays from the position of the focal point toward the inner peripheral surface of the condenser mirror. 2. Each of a plurality of line segments formed by a part of each of a plurality of parabolas different from each other sharing one focal point,
Each of the inner peripheral surfaces of a plurality of rotating curved surfaces obtained by rotating around one axis inclined to the line segment side with respect to the main axis of the parabola passing through the focus and corresponding to each of the line segments is a reflecting surface. An X-ray irradiator that emits X-rays from the position of the focal point toward the inner peripheral surface of the condenser mirror. 3. The X-ray irradiation apparatus according to claim 1, wherein a point X-ray source is arranged at the position of the focal point. 4. The X-ray irradiator according to claim 1, 2 or 3, wherein an X-ray reflective multilayer film is provided on a reflecting surface of the condenser mirror.