JPH065200U - Window device for emitting SOR light in synchrotron - Google Patents

Abstract

(57) [Summary] [Configuration] An emission window 13 for emitting the SOR light 12
The beryllium thin plate 30 to be mounted on the thin plate is curved to have a curved surface, and the curvature of the thin plate is set in relation to the intensity of the SOR light transmitted through each part of the thin plate so that the transmitted optical path length d of the SOR light at each part of the thin plate is Set differently. That is, the curvature of the thin plate is set so that the transmission optical path length becomes larger at the portion where the high intensity SOR light is transmitted. [Effect] Since the transmission optical path length of the SOR light in each part of the thin plate is different, a difference in the transmission attenuation amount of the SOR light in each part of the thin plate occurs accordingly. The strength unevenness is eliminated by itself.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an SOR light extraction line in a synchrotron, and more particularly to a window device for emitting SOR light provided at its tip.

[0002]

[Prior art]

 In recent years, a synchrotron is being developed as a relatively small particle accelerator having a diameter of 10 m or less, and synchrotron radiation (SOR light) emitted from such a synchrotron is used to, for example, a micro LSI of VLSI. It is expected to be applied to various fields such as processing, diagnosis in the medical field, molecular analysis, and structural analysis.

FIG. 6 shows an outline of a synchrotron. An electron beam generated by an electron generator 1 such as an electron gun is accelerated by a linear accelerator (linac) 2 to near the speed of light and deflected by a deflection electromagnet 3. Then, it is incident on the vacuum duct 5 which is a storage ring through the inflector 4. The electron beam incident on the vacuum duct 5 is converged by the converging electromagnet 7 while being given energy by the high-frequency accelerating cavity 6, and is deflected by the deflection electromagnet 8 to continue to orbit the vacuum duct 5. Then, when deflected by the deflecting electromagnet 8, SOR light is generated and emitted through the light extraction line 9 to, for example, the exposure device 10 for use.

FIG. 7 shows a light extraction line 9 in the synchrotron. An oblique incidence mirror 11 is arranged in the middle of the light extraction line 9. The oblique incidence mirror 11 is composed of a plane mirror of oxygen-free copper, SiC, Au, Pt, or the like, or a curved mirror such as a parabolic mirror, and is provided at the end of the line 9 by reflecting the SOR light 12. The light is emitted from the emission window 13. The oblique incidence mirror 11 is supported so as to be swingable in the vertical direction about a shaft 14 as a fulcrum. A rod 16 of a mirror swing mechanism 15 is attached to the end of the oblique incidence mirror 11, and the rod 16 moves in the vertical direction by the rotation of a cam 18 driven by a motor 17. The oblique incidence mirror 11 is swung in the vertical direction so that the reflected light of the SOR light 12 is swung in the vertical direction. Since the SOR light 12 emitted from the accumulation ring originally has a small spread in the vertical direction, the exposure area is expanded in the vertical direction by swinging the grazing incidence mirror 11 as described above. This is to secure a large exposure area for LSI exposure.

By the way, the emission window 13 for the SOR light 12 emits the SOR light 12 into the atmosphere (or inside the helium chamber where the internal pressure is maintained at about atmospheric pressure) while maintaining a high vacuum inside the light extraction line 9. Since a beryllium thin plate 19 having a high transmittance of SOR light 12 and an excellent mechanical strength is mounted because it requires a function, the conventional window 13 is mounted on the window 13 of the mirror 11 as shown in FIG. The beryllium thin plate 19 mounted on such a large window 13 has a large thickness in order to ensure mechanical strength because it has a large area corresponding to the entire exposed area enlarged by movement. As a result, there is a problem that the transmittance of the SOR light 12 is reduced.

Therefore, as shown in FIGS. 9 and 10, for example, a bellows 20 is provided at the front end of the light extraction line 9 so that the oblique incidence mirror 11 can swing the SOR light 12 upward and downward. By oscillating the tip of the line 9 in synchronism, the window 13 is vertically displaced so that the area of the window 13 becomes approximately equal to the irradiation range of the SOR light 12 as shown in FIG. It has also been proposed to reduce the size of the beryllium thin plate 19 that is mounted on the window 13 to be smaller and thinner.

Further, in X-ray lithography, a method has been proposed in which scanning is performed with SOR light in a state where a mask and a wafer are integrated. In this method, for example, as shown in FIG. 12, in order to cut the short wavelength side of the SOR light 21 and collect the light, a light collecting mirror 22 whose mirror surface is a cylindrical curved surface is used. Place it on the street. In this case, the window 23 has a circular shape wider than the irradiation range 24 of the SOR light 21 as shown in FIG. 13. Therefore, the beryllium thin plate 25 mounted on the window 23 also has a circular shape.

[0008]

[Problems to be solved by the device]

 By the way, when a curved mirror such as a parabolic mirror is used as the oblique incidence mirror 11 in the light extraction line 9 as described above, there arises a problem that the reflected light reflected by the mirror 11 has uneven intensity. ing. As shown in FIG. 14, when a parabolic mirror is used as the mirror 11, the reflected light becomes parallel light, but the reflected light becomes dense on the upper side and becomes lower on the lower side as shown in FIG. It is unavoidable that there is a sparse and dense state in which the intensity of the reflected light becomes higher toward the upper side, which causes unevenness in the intensity of the SOR light that is actually used. is there.

Similarly, in X-ray lithography, since the collecting mirror 22 whose mirror surface is a cylindrical curved surface is used, the light intensity at the central portion of the SOR light 21 is weak as shown in FIG. However, there is a problem that curved intensity unevenness is generated such that the light intensity becomes stronger from the central portion to the outside. This is because the reflected light reflected by the condenser mirror 22 is parallel light, but the reflected light has a larger reflection angle in the peripheral portion than in the central portion, and therefore the reflected light is sparse in the central portion. It is unavoidable that a dense and dense state occurs in the peripheral part, and the light intensity becomes sparse in the central part and shows an intensity distribution that gradually becomes denser from the central part to the peripheral part. Intensity unevenness occurs in the SOR light used at that time.

[0010]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides an emission window for emitting SOR light at the tip of a line for extracting light from a synchrotron, and the emission window is provided with a vacuum in the line. In a window device for emitting SOR light, which is equipped with a beryllium thin plate for holding the SOR light and transmitting the SOR light, the beryllium thin plate is curved, and the curvature of the SOR light is transmitted through each part of the thin plate. It is characterized in that the transmission optical path length of the SOR light in each part of the thin plate is set to be different so as to make the intensity of the SOR light after transmission equal to the intensity of the light.

[0011]

[Action]

 Since the beryllium thin plate in the device of the present invention is curved, the transmission optical path length of the SOR light in each part of the thin plate is different. The larger the transmitted optical path length, the greater the amount of attenuation of the SOR light. Therefore, the curvature of the thin plate should be set according to the intensity of the SOR light incident on each part of the thin plate so that the transmitted optical path length of that part is optimal. In other words, by setting the curvature of the thin plate so that the transmission optical path length becomes larger in the portion through which the high intensity SOR light is transmitted, the variation in the intensity of the SOR light before passing through the thin plate is reduced. It is possible to eliminate it by only transmitting

[0012]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 show a window device for SOR light emission in a synchrotron according to a first embodiment of the present invention, which has a light extraction line as shown in FIGS. 9 to 11, for example. 9 is applied. FIG. 1 shows the tip of the light extraction line 9. Reference numeral 5 is a vacuum duct, 13 is an emission window for the SOR light 12 provided at the tip, and 30 is attached to the emission window 13. It is a beryllium thin plate 30.

The beryllium thin plate 30 in this embodiment has a mechanical strength capable of holding a high vacuum in the vacuum duct 5 as in the conventional one, but the conventional thin plate 19 is a flat plate. On the other hand, in the present embodiment, the vacuum duct 5 is bent so as to be convex. Then, about half of the upper side thereof is attached to the emission window 13, and the SOR light 12 is transmitted therethrough.

The thickness of the thin plate 30 of beryllium is constant throughout, but the curvature thereof corresponds to the intensity of the SOR light 12 transmitted through each part of the thin plate 30, and the SOR light 12 after the transmission. In order to equalize the intensity of the SOR light 12, the transmission optical path length of the SOR light 12 in each part of the thin plate 30 is set to be different.

That is, as described above, since the SOR light 12 entering the exit window 13 is reflected by the oblique incidence mirror 11 in the preceding stage, its intensity is higher toward the upper side as shown in FIG. It has become large, and in the prior art, it is transmitted through the emission window 13 with such variations in intensity, and variations in intensity remain after transmission.

However, in the apparatus of this embodiment, since the thin plate 30 is curved, the transmission optical path length d of the SOR light 12 passing through each part of the thin plate 30 is not uniform, which is shown in FIG. Thus, the transmitted light path length d becomes longer as it passes through the upper side of the exit window 13. Although FIG. 2 schematically shows the three SOR lights 12a, 12b, 12c, the transmission optical path length d1 of the SOR light 12a transmitted through the lowermost part of the emission window 13 is the shortest (in this case, the thin plate 30). Of the SOR light 12b having the longest length, and the transmission optical path length d2 of the SOR light 12b passing through the uppermost portion is the longest, and the transmission optical path length d3 of the SOR light 12c passing through the middle portion of the emission window 13 is in the middle thereof.

Since the SOR light 12 is attenuated as the transmitted light path length d is longer, the higher the intensity of the SOR light 12 transmitted through the upper side of the emission window 13 is, the larger the attenuation amount is. Therefore, while considering the transmitted light path length d in each part of the thin plate 30 and the attenuation rate in that part, the thin plate 30 is optimized so that the transmitted light path length d in each part becomes optimum according to the intensity of the SOR light 12 in each part before transmission. By setting the curvature of 30, it is possible to eliminate the nonuniformity of the strength before the transmission only by transmitting the thin plate 30. In other words, in order to make the intensity of the SOR light 12 in each part after transmission uniform, the transmitted light path length d in each part of the thin plate 30 should be optimized, that is, the higher the intensity of the SOR light 12 is, The bending ratio of the thin plate 30 may be set so that the transmitted light path length d becomes large. The curved shape of the thin plate 30 set in this way is determined by the shape and size of the exit window 13, the attenuation factor of the thin plate 30, and the like. Approximately, for example, a spherical surface, a cylindrical surface, or a parabola. It can be a face.

It should be noted that the same effect may be obtained by increasing or decreasing the thickness of each part while keeping the thin plate flat (that is, increasing the thickness of the thin plate toward the upper side of the window). This is not realistic considering the processing accuracy of the beryllium thin plate. Further, in the above embodiment, the thin plate of beryllium is curved so as to be convex toward the vacuum duct, but it may be curved in the opposite direction. Further, it goes without saying that the mounting structure of the thin plate on the emission window may be changed as appropriate.

Second Embodiment FIG. 3 shows a window device for SOR light emission in a synchrotron according to a second embodiment of the present invention, which is applied to a light extraction line 9 as shown in FIG. 12, for example. It is a thing. FIG. 3 shows the tip of the light extraction line 9. Reference numeral 5 is a vacuum duct, 23 is an emission window for the SOR light 21 provided at the tip, and 31 is attached to the emission window 23. It is a thin plate of beryllium.

The thin plate 31 of beryllium in the present embodiment has mechanical strength capable of holding a high vacuum in the vacuum duct 5 like the thin plate 30 of the first embodiment, and is the same as the thin plate 30 described above. The different point is that the whole is attached to the emission window 23 in a curved state so as to be convex toward the vacuum duct 5, and the SOR light 21 is transmitted through the entire emission window 23.

Further, the thickness of the beryllium thin plate 31 is made constant throughout, and the curvature thereof corresponds to the intensity of the SOR light 21 transmitted through each part of the thin plate 31, and the intensity of the SOR light 21 after transmission. In order to equalize the above, the transparent optical path length of the SOR light 21 in each part of the thin plate 31 is set to be different, which is also similar to the thin plate 30.

Here, a case where the SOR light 21 is incident on the thin plate 31 will be described. The reflected light intensity of the SOR light 21 entering the exit window 23 is such that the light intensity at the central portion of the SOR light 21 is weak as shown in FIG. 3, and the light intensity is gradually increased from the central portion to the outside. Although it has a uniform intensity unevenness, the transmission optical path length of each part is optimized according to the intensity of the SOR light 21 of each part before transmission while taking into consideration the transmission optical path length in each part of the thin plate 31 and the attenuation rate in that part. By setting the curvature of the thin plate 31 on the SOR light 21, the attenuation amount of the SOR light 21 passing through each part of the thin plate 31 gradually increases from the central part to the peripheral part of the exit window 23. The transmitted light intensity of the SOR light 21 becomes uniform in the surface direction.

Next, the result of the simulation analysis of the SOR light emitting window device will be described. 4 shows the reflected light intensity distribution (R) of the SOR light 21 in the radial direction (D) before entering the thin plate 31, and FIG. 5 shows the SOR in the radial direction (D) after passing through the thin plate 31. 3 shows a transmitted light intensity distribution (T) of the light 21. These scales are arbitrary. Here, the SOR light 21 has a resist surface output of 370 mW / cm ² at a 7 m point of 1.2 GeV light, and the thin plate 31 has a diameter of 50 mm, a thickness of 30 μm, and a radius of curvature of 85 mm. Was used. From these results, the reflected light intensity of the SOR light 21 has a weak intensity in the central portion and a curved intensity unevenness in which the light intensity gradually increases from the central portion to the outside. It is apparent that the transmitted light intensity of the SOR light 21 becomes uniform in the in-plane direction by transmitting the light.

As described above, according to the thin plate 31 of the second embodiment, the whole of the emission plate 22 is attached to the emission window 22 while being curved so as to be convex toward the vacuum duct 5 side. Since the SOR light 12 is configured to pass therethrough, the intensity of the reflected light of the SOR light 21 entering the exit window 23 is weak in the central portion and gradually increases from the central portion to the outside. Even if there is intensity unevenness, the transmitted light intensity of the SOR light 21 passing through each part of the thin plate 31 can be made uniform in the surface direction, and the light intensity distribution after transmission can be made extremely uniform. it can.

[0025]

As described above, according to the present invention, the beryllium thin plate attached to the emission window for emitting the SOR light is curved, and the curvature of the thin plate is transmitted through each part of the thin plate. Since the transmission optical path lengths in each part of the thin plate are set to be different so as to equalize the intensity after transmission corresponding to the intensity of SOR light, there is a difference in the attenuation amount due to the difference in the transmission optical path length. It is possible to eliminate the unevenness of the intensity of the SOR light by itself and to even out the intensity of the SOR light emitted from the emission window.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a window device for emitting SOR light which is a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the device.

FIG. 3 is a side sectional view showing a schematic configuration of a SOR light emitting window device according to a second embodiment of the present invention.

FIG. 4 S in the radial direction (D) before entering the thin plate of the present invention
It is a figure which shows the reflected light intensity distribution (R) of OR light.

FIG. 5: S in the radial direction (D) after passing through the thin plate of the present invention
It is a figure which shows the transmitted light intensity distribution (T) of OR light.

FIG. 6 is a diagram showing an outline of a synchrotron.

FIG. 7 is a schematic configuration diagram showing an example of a light extraction line in the synchrotron.

FIG. 8 is a view showing an emission window of SOR light on the same line.

FIG. 9 is a schematic configuration diagram showing another example of a light extraction line in the same synchroton.

FIG. 10 is a diagram showing an operating state of the same line.

FIG. 11 is a view showing an emission window of SOR light on the same line.

FIG. 12 is a schematic configuration diagram showing another example of a light extraction line in the synchrotron.

FIG. 13 is a view showing an emission window of SOR light on the same line.

FIG. 14 is a diagram for explaining a situation of reflection of SOR light by an oblique incidence mirror.

[Explanation of symbols]

 d, d1, d2, d3 transmission optical path length 5 vacuum duct 9 light extraction line 12, 12a, 12b, 12c SOR light 13 emission window 23 emission window 30 thin plate 31 thin plate

Claims (1)

[Scope of utility model registration request] 1. A beryllium thin plate for providing an exit window for emitting SOR light at the tip of a light extraction line of a synchrotron and for holding the vacuum in the line and transmitting the SOR light at the exit window. In the window device for emitting SOR light, the thin plate of beryllium is curved, and the curvature thereof corresponds to the intensity of SOR light transmitted through each part of the thin plate.
SOR in each part of the thin plate to make the intensity of R light uniform
A window device for SOR light emission in a synchrotron, characterized in that different transmission light path lengths of light are set.