JPH0668999A - Condensing method for synchrotron radiation - Google Patents

Abstract

PURPOSE:To enable irradiation of a light having a constant intensity over the entire area of an object to be irradiated when a synchrotron radiation is swung in the vertical direction by putting a reflection mirror close to or apart from an electron storage ring in accordance with an incident glancing angle of the light to the reflection mirror. CONSTITUTION:A concave smooth reflection surface 12a of a reflection mirror 12 is irradiated with synchrotron radiation 11 emitted from an electron storage ring 10, and the radiation light 11 reflected on the reflection mirror 12 is radiated to an object to be irradiated. The reflection mirror 12 is put close to a ring 10 along the light axis 11a of the radiation light 11 in accordance with an increase in an incident glancing angle theta of the radiation light 11 to the reflection surface 12a and put apart from the ring 10 along the light axis 11a in accordance with a decrease in the incident glancing angle theta. Thus, when the radiation light 11 is swung by changing the glancing angle theta in the vertical direction to irradiate the entire area of a substrate 20, the radiation light 11 always forms an image on the substrate 20 by moving the position of the reflection mirror 12 along the light axis 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to irradiating a reflecting surface of a reflecting mirror with synchrotron radiation and irradiating an object with the synchrotron radiation reflected by the reflecting mirror. The present invention relates to a method for condensing and scanning synchrotron radiation, which allows irradiation of the entire area of an object to be irradiated with synchrotron radiation of constant intensity even if the synchrotron radiation is shaken in the vertical direction.

[0002]

2. Description of the Related Art Next, a conventional method for collecting synchrotron radiation light will be described with reference to FIGS. Figure 1
FIG. 3 is a schematic side sectional view showing a method of collecting synchrotron radiation by a reflecting mirror, and FIG. 3 is a diagram for explaining a conventional method of collecting synchrotron radiation. A perspective view of the reflecting mirror, and FIG. 3B is an intensity distribution map of the synchrotron radiation emitted to the irradiation object.

As shown in FIG. 1, a synchrotron radiation light 11 emitted from an electron storage ring 10 which orbits charged particles e such as electrons in a horizontal direction at a speed close to the speed of light is a beam line (not shown). It is reflected by the reflector 12 which is arranged inside the optical axis 11a of the synchrotron radiation 11 and the reflecting surface 12a which reflects the synchrotron radiation 11, that is, the angle θ, that is, the viewing angle θ can be freely changed. After that, the film was taken out into the atmosphere from a diaphragm (not shown) arranged at the end of the beam line, and was irradiated to an object to be irradiated, for example, a substrate 20 coated with a resist through a mask (not shown).

As described above, the reflecting mirror 12 interposed between the electron storage ring 10 and the substrate 20 is curved so that the reflecting surface is concave in the direction orthogonal to the optical axis 11a of the synchrotron radiation 11. There are often used such reflecting mirrors, for example, a toroidal mirror (see FIG. 3 (a)) formed by bending a cylindrical mirror whose reflecting surface has the shape of an inner surface of a cylinder along its cylindrical generatrix.

This means that in order to transfer (exposure) an integrated circuit or the like using the synchrotron radiation 11, it is necessary to uniformly irradiate an area of about 30 × 30 mm on the substrate 20 coated with the resist.

However, the synchrotron radiation 11 is wide enough in the horizontal direction, but spreads only about 1 mrad in the vertical direction. For this reason, it is necessary to use a toroidal mirror or the like to focus light in the horizontal direction, and also to vibrate the mirror in the vertical direction to scan / enlarge the synchrotron radiation light 11.

However, since the focal length of the toroidal mirror strongly depends on the angle of the synchrotron radiation 11 incident on this mirror, the focusing conditions greatly differ at each position when scanning and expanding in the vertical direction. There was a problem that irradiation was not possible.

[0008]

By the way, for simplicity, the reflecting mirror 12 is a cylindrical mirror, and the distance from the electron storage ring 10 which is the light source of the synchrotron radiation 11 to the reflecting mirror 12 is L ₁ , When the distance from the light source to the substrate 20, which is the imaging position of the synchrotron radiation 11, is L ₀ , the following formula is derived from the lens formula.

1 / L ₁ + 1 / (L ₀ −L ₁ ) = 1 / F ₁ where F ₁ is a cylinder whose curvature of the reflecting surface 12 a is R when the value of the oblique angle θ is θ _1. It is the focal length of the mirror-shaped reflecting mirror 12 and can be expressed by the following formula.

F ₁ = R / (2 × Sin θ ₁ ) Therefore, if the value of the oblique angle θ is changed from θ ₁ to θ ₂ ,
An approximate expression of the moving distance ΔS of the irradiation position of the synchrotron radiation 11 on the substrate 20 is ΔS = (L ₀ −L ₁ ) × Tan (2 × (θ ₂ −θ ₁ )).

As described above, the irradiation position of the synchrotron radiation 11 on the substrate 20 is such that the value of the oblique angle θ changes from θ ₁ to θ _2.
However, the focal length of the reflecting mirror 12 is also changed from F ₁ to F ₂ (F ₂ = R / (2 × Sin
θ ₂ )), the imaging position of the synchrotron radiation 11 is also displaced.

If the deviation of the image formation position of the synchrotron radiation 11 is ΔF, ΔF is given by the following equation. ΔF = R / 2 (1 / Sinθ ₂ −1 / Sinθ ₁ ) Therefore, in the case of θ ₂ > θ ₁ , the image formation position of the synchrotron radiation 11 is closer to the reflecting mirror 12 than in the case of θ _1. Further, in the case of θ ₂ <θ ₁ , the image forming position of the synchrotron radiation 11 moves in the direction away from the reflecting mirror 12 as compared with the case of θ ₁ .

Therefore, if the synchrotron radiation 11 is swung in the vertical direction with the positional relationship between the reflecting mirror 12 and the substrate 20 fixed, and the synchrotron radiation 11 is applied to the entire area of the substrate 20, the result is The image position will gradually deviate from the substrate 20.

As a result, as shown in FIG. 3 (b), the substrate 20
The irradiation range of the synchrotron radiation 11 irradiating the substrate gradually changes, and there is a problem that the substrate 20 cannot be irradiated with a uniform intensity.

In FIG. 3 (b), the reflecting mirror 12 (see FIG. 3 (a)) has a curvature R of 90 mm in a direction (cylindrical generatrix direction) perpendicular to the optical axis of the synchrotron radiation 11 and a synchrotron. Direction parallel to optical axis 11a of synchrotron radiation 11 (direction of cylinder line)
Has a curvature R'of 90,000 mm, and the distance from the light emitting point of the synchrotron radiation 11 (electron storage ring 10) to the reflecting mirror 12 is 1700 mm, from the light emitting point of the synchrotron radiation 11 to the substrate 20. Distance is 9000mm
Under the condition of, the value of the oblique angle θ is changed from 26 mrad to 28.7 m.
This shows the irradiation range of the synchrotron radiation 11 on the substrate 20 when changed to rad.

The present invention has been made to solve the above problems, and an object thereof is to irradiate synchrotron radiation with a constant intensity even if the synchrotron radiation is shaken in the vertical direction. An object of the present invention is to provide a method for collecting synchrotron radiation that allows irradiation of the entire area of an object.

[0017]

The object is to irradiate a smooth concave reflecting surface 12a of a reflecting mirror 12 with synchrotron radiation 11 emitted from an electron storage ring 10 as shown in FIG. In the method of condensing synchrotron radiation 11 which irradiates an object 20 with the synchrotron radiation 11 reflected by a reflecting mirror 12, the synchrotron radiation 11 is a reflecting mirror.
In response to an increase in the visual oblique angle θ incident on the reflecting surface 12a of 12, the reflecting mirror 12 approaches the electron storage ring 10 along the optical axis 11a of the synchrotron radiation 11, and the visual oblique angle θ decreases. This is achieved by a method of collecting synchrotron radiation, which is characterized in that the reflecting mirror 12 is separated from the electron storage ring 10 along the optical axis 11a of the synchrotron radiation 11.

[0018]

[Function] The distance from the light source of the synchrotron radiation 11 to the reflecting mirror 12 is L ₁ (L ₂ ), the distance from the light source of the synchrotron radiation 11 to its image forming position is L ₀ (L ₀ ), and Let F ₁ (F ₂ ) be the focal length of the reflector 12 having a curvature R in the direction orthogonal to the optical axis 11a of the synchrotron radiation 11 when the value of the oblique angle θ is θ ₁ (θ ₂ ). , The following formula is derived from the lens formula.

1 / L ₁ + 1 / (L ₀ −L ₁ ) = 1 / F ₁ (1) 1 / L ₂ + 1 / (L ₀ −L ₂ ) = 1 / F ₂ (2) F ₁ = R / (2 × Sinθ ₁ ) (3) F ₂ = R / (2 × Sinθ ₂ ) (4) Therefore, the value of the visual oblique angle θ is changed from θ ₁ to θ ₂ ,
From the light source of the synchrotron radiation 11 to its imaging position (substrate
The above equation (2) can be established by changing only the distance L ₂ from the light source of the synchrotron radiation 11 to the reflecting mirror 12 without changing the distance L ₀ to 20).

That is, if θ ₂ > θ ₁ , then the reflecting mirror 12
Is brought close to the light source of the synchrotron radiation 11, the synchrotron radiation 11 reflected by the reflecting mirror 12 whose viewing angle θ is changed from θ ₁ to θ ₂ forms an image on the substrate 20, and θ
_{If 2} <θ ₁ , the reflecting mirror 12 is moved to the synchrotron radiation 11
When separated from the light source of, the synchrotron radiation light 11 reflected by the reflecting mirror 12 whose viewing angle θ is changed from θ ₁ to θ ₂ is imaged on the substrate 20.

Therefore, even if the synchrotron radiation 11 is shaken in the vertical direction by changing the viewing angle θ, the position of the reflecting mirror 12 is aligned with the optical axis 12a of the synchrotron radiation 11 when irradiating the whole area on the substrate 20. By moving along, the synchrotron radiation 11 can always be imaged on the substrate 20.

Thus, the method for collecting synchrotron radiation according to the present invention makes it possible to irradiate the whole area of the substrate with synchrotron radiation having a constant intensity even if the synchrotron radiation is shaken in the vertical direction. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A synchrotron radiation light generating apparatus according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a side sectional view of an essential part schematically showing a method of collecting synchrotron radiation by a reflecting mirror, and FIG. 2 is a diagram for explaining a synchrotron radiation generator of one embodiment of the present invention. FIG. 1 (a) is a side view of an essential part of one embodiment of the present invention,
FIG. 1B is a front view of a main part of one embodiment of the present invention, and FIG. 1C is an intensity distribution chart of synchrotron radiation of a synchrotron irradiation object irradiated on the irradiation object.

In the present specification, the same parts, the same materials and the like are designated by the same reference numerals throughout the drawings. The synchrotron radiation light generating apparatus of one embodiment of the present invention is configured such that the viewing angle θ changes according to the amount of lateral movement of the reflecting mirror 12 as shown in FIGS. 1 and 2. When the reflecting mirror 12 is moved closer to the electron storage ring 10 (moved to the left on the paper surface), the visual oblique angle θ increases, and when the reflecting mirror 12 is moved away from the electron storage ring 10 (moved to the right on the paper surface), the visual tilt angle θ increases. The angle θ is configured to be small.

That is, as shown in FIGS. 2A and 2B, the synchrotron radiation generator of one embodiment of the present invention comprises a pair of rails laid parallel to each other and separated from each other in the beam line. Horizontal movement guide rail 14 consisting of 14a,
Right upward guide grooves 15a are provided on the inner side surfaces which are parallel to each other and are separated from each other and face each other. Directly above the horizontal movement guide rail 15, the beam line 13 is parallel to the horizontal movement guide rail 14.
Inside the guide groove of the glancing angle setting guide rail 15, the glancing angle setting guide rail 15 and the rolling roller 16 rolling on the horizontally moving guide rail 14 are fixed to the center part on the back side. Reflecting mirror 12 with guide roller 17 rolling on 15a fixed to the end on the surface (mirror surface) side (the end on the right side of the paper).
And a horizontal moving device (not shown) for freely moving the reflecting mirror 12 to the left and right by rolling the rolling roller 16 on the horizontal moving guide rail 14.

Since the curvature of the guide groove 15a of the above glancing angle setting guide rail 15 in the left-right direction on the paper surface is based on the above-mentioned equations (1) to (4), the horizontal movement device is used. As the reflection mirror 12 is moved closer to the electron storage ring (not shown) (moved to the left on the paper surface), the viewing angle θ continuously increases, and the reflection mirror 12 is separated from the electron storage ring (to the right on the paper surface). As it moves, the viewing angle θ decreases continuously.

Therefore, to explain this with reference to FIG. 1, when the reflecting mirror 12 is moved from the position shown by the solid line to the position shown by the dotted line, the synchrotron radiation 11 reflected by the reflecting surface 12a of the reflecting mirror 12 is on the substrate 20. This substrate 20 while focusing on
It will move continuously from the upper end to the lower end.

In this way, the synchrotron radiation 11 for irradiating the substrate 20 from its upper end to its lower end is always the substrate 20.
Since the image is formed above, the irradiation range of the synchrotron radiation 11 on the substrate 20 is substantially constant as shown in FIG. 2 (c). The data in Fig. 2 (c) is shown in Fig. 3 (b).
Of course, the data is obtained by using the same thing as the reflecting mirror 12 which obtained the data.

As a result, if a resist (not shown) is applied to the surface of the substrate 20, this resist will be uniformly exposed.

[0030]

As described above, the present invention makes it possible to irradiate the entire area of the object to be irradiated with synchrotron radiation having a constant intensity even if the synchrotron radiation is shaken in the vertical direction.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part schematically showing a method of collecting synchrotron radiation by a reflecting mirror,

FIG. 2 is a view for explaining a synchrotron radiation light generation device of one embodiment of the present invention,

FIG. 3 is a diagram for explaining a conventional method for collecting synchrotron radiation light.

[Explanation of symbols]

 10 is an electron storage ring, 11 is synchrotron radiation, 11a is an optical axis, 12 is a reflector, 12a is a reflecting surface, 14 is a horizontal guide rail, 14a is a rail, and 15 is a sight line. Corner setting guide rails, 15a indicate guide grooves, respectively.

Claims (1)

[Claims] 1. A smooth concave reflecting surface of a reflecting mirror (12)
The (12a) is irradiated with the synchrotron radiation (11) emitted from the electron storage ring (10), and the synchrotron radiation (11) reflected by the reflecting mirror (12) is applied to the irradiation target (20). In the method of collecting the synchrotron radiation to be applied, the synchrotron radiation (11) is reflected on the reflecting surface (12a) of the reflecting mirror (12).
In accordance with the increase of the visual oblique angle (θ) incident on the synchrotron radiation (11), the reflecting mirror (12) approaches the electron storage ring (10) along the optical axis (11a), Synchrotron radiation with decreasing (θ)
A reflector (12) is attached along the optical axis (11a) of (11) to the electron storage ring.
A method for collecting synchrotron radiation, characterized by separating from (10).