JP2584490Y2 - Window device for SOR light emission in synchrotron - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SOR light extraction line in a synchrotron, and more particularly to a window device for SOR light emission provided at the end thereof.

[0002]

2. Description of the Related Art In recent years, a synchrotron has been developed as a relatively small particle accelerator having a diameter of 10 m or less.
Utilization of synchrotron radiation (SOR light) emitted from such a synchrotron is expected to be applied to various fields such as micro processing of ultra LSI, diagnosis in the medical field, molecular analysis, and structural analysis. ing.

FIG. 6 shows an outline of a synchrotron. An electron beam generated by an electron generator 1 such as an electron gun is accelerated to near the speed of light by a linear accelerator (linac) 2 and deflected by a deflection electromagnet 3. Then, the light enters the vacuum duct 5 as a storage ring via 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, deflected by the deflection electromagnet 8, and continues to go around in the vacuum duct 5.
When deflected by the deflecting electromagnet 8, SOR light is generated, and is emitted through the light extraction line 9 to, for example, the exposure device 10 and used.

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 constituted by a plane mirror such as oxygen-free copper, SiC, Au, Pt, or a curved mirror such as a parabolic mirror.
The SOR light 12 is reflected and emitted from an emission window 13 provided at an end of the line 9. The above-mentioned oblique incidence mirror 11 is supported so as to be vertically swingable about a shaft 14 as a fulcrum. A rod 16 of a mirror swing mechanism 15 is attached to an end of the oblique incidence mirror 11, and the rod 16 is a cam 18 driven by a motor 17.
The mirror rotates vertically so that the oblique incidence mirror 11 swings up and down, and the reflected light of the SOR light 12 swings up and down. Such a configuration is based on the SOR emitted from the storage ring.
Since the light 12 originally has a small spread in the vertical direction, the swing of the oblique incidence mirror 11 expands the exposure area in the vertical direction to secure a large exposure area for LSI exposure.

By the way, the exit window 13 of the SOR light 12 is
Since a function of emitting the SOR light 12 into the atmosphere (or into a helium chamber where the internal pressure is maintained at about the atmospheric pressure) while maintaining a high vacuum inside the light extraction line 9 is required, the transmittance of the SOR light 12 is reduced. A beryllium thin plate 19 having high mechanical strength and excellent mechanical strength is attached.
As shown in FIG. 8, the beryllium thin plate 19 mounted on such a large window 13 is a machine having a large area corresponding to the entire exposure area enlarged by the swing of the mirror 11. In order to secure the target strength, the plate thickness is increased, and as a result, there is a problem that the transmittance of the SOR light 12 is reduced.

For this reason, for example, as shown in FIGS.
The window 13 is vertically displaced by swinging the tip of the line 9 in synchronization with the vertical swing of the SOR light 12 by the oblique incidence mirror 11, whereby As shown in FIG. 11, the area of the window 13 is
It has also been proposed to reduce the size of the beryllium sheet 19 attached to the window 13 to a size as small as possible, so as to be as small as the irradiation range of FIG.

In X-ray lithography, SO
A method has been proposed in which a mask and a wafer are scanned in an integrated state with respect to R light. In this method, as shown in FIG. 12, for example, in order to cut and condense the short wavelength side of the SOR light 21, a converging mirror 22 having a mirror-shaped curved surface is provided on the optical path of the SOR light 21. To place.
In this case, the shape of the window 23 is SOR as shown in FIG.
The circular shape is wider than the irradiation range 24 of the light 21. Therefore, the beryllium thin plate 25 mounted on the window 23 is also circular.

[0008]

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, the intensity of the light reflected by the mirror 11 is high. There is a problem that unevenness occurs. This is because, when a parabolic mirror is used as the mirror 11 as shown in FIG. 14, the reflected light is parallel light, but the reflected light is dense on the upper side and clear on the lower side as is clear from FIG. It is inevitable that a sparse and dense state occurs, and the intensity of the reflected light increases toward the upper side.
That is, the light has uneven intensity.

Similarly, in the case of X-ray lithography, the light intensity of the central portion of the SOR light 21 is weak as shown in FIG. However, there is a problem in that curved surface-shaped intensity unevenness occurs such that the light intensity increases gradually from the central portion to the outside. This is because the reflected light reflected by the condensing mirror 22 is parallel light, but the reflected light has a larger reflection angle in the peripheral part than in the central part. It is inevitable that a dense state such as dense in the part occurs, and the light intensity becomes sparse in the central part and shows an intensity distribution such that the density gradually increases from the central part toward the peripheral part. The intensity unevenness occurs in the used SOR light.

[0010]

According to the present invention, in order to solve the above-mentioned problems, an emission window for emitting SOR light is provided at the tip of a light extraction line of a synchrotron, and the emission window is provided. In a SOR light emission window device equipped with a thin plate of beryllium for holding vacuum in the line and transmitting SOR light, while bending the thin plate of beryllium while keeping the thickness of the thin plate of beryllium constant , The curvature is determined by S which passes through each part of the thin plate.
The transmission optical path length of the SOR light in each part of the thin plate is set to be different in order to equalize the intensity of the transmitted SOR light in accordance with the intensity of the OR light.

[0011]

[Action] thin sheet of beryllium in the apparatus of the present invention is that
Since the wall thickness is constant and curved, the transmitted light path length of the SOR light in each part of the thin plate is different. Since the attenuation of the SOR light increases as the transmitted light path length increases, the curvature of the thin plate should be set so that the transmitted light path length of that portion is optimized according to the intensity of the SOR light entering each part of the thin plate. , That is, high strength SOR
By setting the curvature of the thin plate so that the transmitted light path length becomes larger as the light passes through, the variation in the intensity of the SOR light before passing through the thin plate can be naturally solved only by transmitting the thin plate.

[0012]

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 emitting SOR light in a synchrotron according to a first embodiment of the present invention, for example, a light extraction line 9 as shown in FIGS. 9 to 11. Applicable. FIG. 1 shows a tip of the light extraction line 9, reference numeral 5 denotes a vacuum duct, 13 denotes an emission window of the SOR light 12 provided at the tip, and 30 denotes beryllium mounted on the emission window 13. Of the thin plate 30.

Beryllium thin plate 30 in this embodiment
Has a mechanical strength capable of maintaining a high vacuum in the vacuum duct 5 like the conventional one, but the conventional thin plate 19 has a flat plate shape, whereas the thin plate of the present embodiment has It is curved so as to be convex toward the vacuum duct 5 side. Then, about half of the upper side is mounted on the emission window 13, and the SOR light 12 is transmitted through that portion.

Although the thickness of the beryllium thin plate 30 is constant throughout, the curvature of the beryllium thin plate 30 corresponds to the intensity of the SOR light 12 transmitted through each part of the thin plate 30, and the transmitted SOR light 12 In order to make the intensity of the SOR light uniform, 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, the exit window 13
The SOR light 12 incident on the oblique incidence mirror 1
As shown in FIG. 1, the intensity of the light is increased toward the upper side as shown in FIG. 1, and in the related art, the light passes through the exit window 13 with such a variation in intensity. However, the variation in strength remains.

However, in the apparatus of this embodiment, the thickness is
Since the thin plate 30 having a uniform thickness is curved, the thin plate 30
The transmitted optical path length d of the SOR light 12 passing through the respective portions is not uniform, and as shown in FIG. FIG. 2 schematically shows three SOR lights 12 a, 12 b, and 12 c.
2a has the shortest transmitted optical path length d1 (in this case, the thin plate 3
0), SOR light 12b passing through the top
Is the longest, and the transmitted light path length d3 of the SOR light 12c passing through the middle part of the exit window 13 is intermediate between them.

As the transmitted light path length d increases, the SO
Since the R light 12 is attenuated, the higher the intensity of the SOR light 12 that passes through the upper side of the exit window 13, the greater the attenuation. Therefore, considering the transmitted light path length d in each part of the thin plate 30 and the attenuation rate in that part, the S
By setting the curvature of the thin plate 30 in accordance with the intensity of the OR light 12 so that the transmitted light path length d of each part becomes optimal, the unevenness of the intensity before transmission can be reduced only by transmitting the thin plate 30. It can be resolved by itself. In other words, in order to equalize the intensity of the SOR light 12 in each part after transmission, the transmitted light path length d in each part of the thin plate 30 is set.
The curvature of the thin plate 30 may be set so as to be optimal, that is, so that the transmitted light path length d becomes larger as the high intensity SOR light 12 is transmitted. The curved surface shape of the thin plate 30 set in this way is determined by the shape and size of the exit window 13, the attenuation rate of the thin plate 30, and the like. Plane.

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). It 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 project toward the vacuum duct, but may be curved in the opposite direction. Further, it goes without saying that the mounting structure of the thin plate with respect to the emission window may be appropriately changed.

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

Beryllium thin plate 31 in this embodiment
Has mechanical strength capable of maintaining a high vacuum in the vacuum duct 5 similarly to the thin plate 30 of the first embodiment, and differs from the thin plate 30 described above in that the thin plate 30 has a convex shape on the vacuum duct 5 side. The entirety is mounted on the emission window 23 in a curved state so that the SOR light 21 is transmitted through the entire emission window 23.

The thickness of the beryllium thin plate 31 is constant throughout, and its curvature is
In order to equalize the intensity of the transmitted SOR light 21 in accordance with the intensity of the SOR light 21 transmitted through each portion of the thin plate 31, the transmission optical path length of the SOR light 21 in each portion of the thin plate 31 is also set to be different. It is the same as the thin plate 30.

Here, a case where the SOR light 21 is incident on the thin plate 31 will be described. As shown in FIG. 3, the SOR light 21 entering the exit window 23 has a curved surface whose reflected light intensity is low at the central portion of the SOR light 21 and gradually increases from the central portion to the outside. The intensity of the SOR light 21 in each part before transmission is determined in consideration of the transmitted light path length in each part of the thin plate 31 and the attenuation rate in that part, so that the transmitted light path length in each part becomes optimal. By setting the curvature of the thin plate 31 in advance, the amount of attenuation of the SOR light 21 passing through each part of the thin plate 31 gradually increases from the center to the peripheral part of the emission window 23, and therefore, the SOR light of each part after transmission is transmitted. 2
The transmitted light intensity of No. 1 becomes uniform in the plane direction.

Next, the result of a simulation analysis of the SOR light emitting window device will be described. FIG.
Is the SOR light 21 in the radial direction (D) before entering the thin plate 31
5 shows the reflected light intensity distribution (R) of FIG.
3 shows a transmitted light intensity distribution (T) of the SOR light 21 in the radial direction (D) after passing through No. 1. Note that these scales are optional. Here, the SOR light 21 is 1.2 Ge
The resist surface output at 7m point of V light is 370mW /
cm ² , and the thin plate 31 has a diameter of 50 mm,
The one having 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 exhibits a curved surface unevenness in which the light intensity at the central portion is weak and the light intensity increases gradually from the central portion to the outside, but the transmitted light passes through the thin plate 31. By doing so, it is clear that the transmitted light intensity of the SOR light 21 becomes uniform in the plane direction.

As described above, the thin plate 3 of the second embodiment is
According to 1, the entirety is mounted on the emission window 22 in a state of being curved so as to project toward the vacuum duct 5 side, and the emission window 22 is
Since the entire structure is configured so that the SOR light 12 is transmitted, the curved surface shape is such that the intensity of the reflected light of the SOR light 21 entering the emission window 23 is weak at the central portion and increases gradually from the central portion to the outside. Even when 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 plane direction, and the light intensity distribution after transmission can be made extremely uniform. .

[0025]

[Effects of the Invention] As described above, the present invention provides an SO
The thickness of the beryllium thin plate attached to the exit window for emitting the R light is curved while keeping the thickness constant, and the curvature of the thin plate is adjusted according to the intensity of the SOR light transmitted through each part of the thin plate. Is set so that the transmitted light path length in each part of the thin plate is different in order to equalize
Due to the difference in attenuation caused by the difference in the transmitted light path length, the intensity unevenness of the transmitted SOR light can be naturally eliminated,
There is an effect that the intensity of the SOR light emitted from the emission window can be equalized.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a window apparatus for emitting SOR light according to 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 an SOR light emitting window device according to a second embodiment of the present invention.

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

FIG. 5 shows 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 in the same line.

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

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

FIG. 11 is a diagram showing an emission window of SOR light in the same line.

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

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

FIG. 14 is a diagram for explaining the state 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 Outgoing window 23 Outgoing window 30 Thin plate 31 Thin plate

Claims (1)

(57) [Scope of request for utility model registration] 1. An emission window for emitting SOR light is provided at a tip of a light extraction line of a synchrotron, and a thin plate of beryllium for maintaining vacuum in the line and transmitting SOR light is provided in the emission window. In the SOR light emission window device, the thin plate of beryllium is curved while keeping the thickness of the thin plate constant, and the curvature is transmitted according to the intensity of the SOR light transmitted through each part of the thin plate. An SOR light emitting window device in a synchrotron, wherein the transmitted light path length of SOR light in each part of the thin plate is set to be different so as to equalize the intensity of the subsequent SOR light.