JPH0498800A - Sor device - Google Patents

Abstract

PURPOSE:To deflect and converge an electron beam at the same time in a SOR device for rotating the electron beam at a luminous flux in a synchrotron, so as to extract radiation light, by making the distance of a magnetic pole of a core different in a radius direction of deflection curvature. CONSTITUTION:When an electron beam 12 is moved horizontally from a sheet surface at a deflection part 2a of a vacuum container 2, and when a flux that passes an air gap between magnetic poles 16 and 17, is directed from the lower magnetic pole 17 to the upper magnetic pole 16, as indicated in the figure, a distance d1 on the inside in the radius direction of a deflection curvature is smaller than a distance d0 outside. Since Lorentz's force and inertia force due to the acceleration in the direction of a radius (r) of an electron rotated stably on the central trajectory, are balanced, the electron which is diverted from the central trajectory, receives a force F0 on the inside, or a force F1 on the outside, according to conditions. While an electron beam 12 is deflected at the deflection part 2a, it is also converged. By making the electron beam 12 deflected and converged at the same time at the deflection part 2a, only a little adjustment of the conversion force by quadrupole electromagnet for flattening, is required, and the control thereof is thus facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an SOR device that extracts synchrotron radiation by making an electron beam circulate at the speed of light within a synchrotron, and in particular effectively utilizes the electron focusing power of a bending electromagnet. The present invention relates to an SOR device.

[Prior Art] Recently, SOR devices have been attracting attention as light sources for semiconductor lithography.

The SOR device rotates an electron beam in a storage ring at the speed of light and extracts synchrotron radiation (SOR light) emitted when the electron beam is deflected by a magnetic field.

Usually, a large SOR device consists of three devices: a linear accelerator, a synchrotron, and a storage ring, or a small SOR device consists of three devices: a linear accelerator, a synchrotron, and a storage ring.
An OR device that combines a synchrotron and a storage ring is currently being developed.

In this small SOR device, low-energy electrons of 100 M e V or less are repeatedly injected into the synchrotron from a linear accelerator, and once a predetermined accumulated M current is secured in the synchrotron, the The electron beam energy is increased to the final energy to extract SO and R light.

This SOR device will be explained with reference to FIG.

In Fig. 3, 1 is a synchrotron, which includes an annular vacuum vessel 2 in which an electron beam circulates, a high-frequency acceleration cavity 3 that replenishes energy to the electron beam orbiting inside the vacuum vessel 2, and a constant-frequency accelerating cavity 3 that deflects the electron beam. V, and a conductive electromagnet 4. Reference numeral 5 designates an electron generator, 6 an acceleration tube, 7 a deflection electromagnet at the entrance section, 8 a light extraction line, and 9 an exposure device.

Electrons from the electron generator 5 are accelerated to, for example, 4 M e V in an accelerating tube 6, deflected by a deflecting electromagnet 7 in the entrance section, and then entered into the vacuum vessel 2.

The electrons entering the vacuum container 2 are deflected by the deflection electromagnet 4, and circulate within the vacuum container 2 at the speed of light while being supplied with energy in the high frequency acceleration cavity 3. After this electron injection is repeated and a predetermined current is accumulated in the synchrotron 1, the magnetic field of the bending electromagnet 4 is gradually increased to adjust the energy of the electron beam to the final energy (for example, 800 M e
V) i during which the SOR light emitted in the tangential direction of the beam deflected by the deflecting magnet 4 is taken out from the light extraction line 8 and enters the exposure device 9 to perform phosphorography of the semiconductor. Problems to be Solved] By the way, this synchrotron 1 is equipped with a horizontal four-i electromagnet 10. to adjust the size of the electron beam orbiting within the vacuum vessel 2. A vertical quadrupole S magnet 11 is provided, and these electromagnets adjust the convergence of electrons. Now, FIG. 4 schematically shows the horizontal quadrupole electromagnet 10. In FIG. 4, if the electron beam 12 moves in the vacuum chamber 2 both to the left and right from the plane of the paper shown in the figure, by applying the horizontal 4i to the magnetic fluxes B+ and Bo between the magnetic poles of the magnet 10 as shown in the figure. By generating forces F, , Fo that converge the electron beam 12 from both sides, the horizontal convergence force of the electron beam 12 can be adjusted. Further, the vertical quadrupole electromagnet 11 may also form a magnetic field so as to converge the electron beam from above and below with the electron beam as the boundary.

However, these quadrupole magnets are not suitable for electron storage operation or S
During OR operation, it is necessary to control and adjust the focusing force according to the energy of the electron beam, that is, according to the strength of the magnetic field of the deflection magnet 4. In particular, since the electron beam tends to spread horizontally, the control of the horizontal quadrupole electromagnet 10 becomes complicated and its power consumption becomes large.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an SOR device that can focus an electron beam in horizontal and vertical directions by reducing the amount of excitation of a quadrupole electromagnet.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a vacuum vessel in which an electron beam circulates, and a deflection section of the vacuum vessel between the magnetic poles of a core around which a deflection coil is wound. In this SOR device, the spacing between the magnetic poles of the core is varied in order to provide a magnetic field distribution in the direction of the deflection curvature radius of the electron beam.

[Function] According to the above configuration, by making the spacing between the magnetic poles of the core different in the direction of the radius of deflection curvature, that is, by creating a magnetic field distribution in which the magnetic field is stronger on the inside than on the outside with respect to the locus of the deflection part, the deflection part It is possible to focus the electron beam with

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

The overall configuration of the SOR device is as described above with reference to FIG.

As shown in FIG. 1, the deflection electromagnet 4 is constructed by providing deflection coils 18 on the upper and lower magnets f#l 16 and 17 of a core 15 having a C-shaped cross section, respectively. This pole piece 16.17
The deflection part 2a of the vacuum container 2 is in between! be done. Assuming that the center of curvature of the deflection section 2a of the vacuum vessel 2 is on the left side in the figure, the spacing d between the magnetic poles 16° and 17 is the distance d of the inner side in the direction of the radius of deflection curvature centering on the electron beam 12 passing through the deflection section 2a. The distance d+ is formed to be smaller than the outer distance d0. Further, the coil 18 is energized so that the lower magnetic pole 17 is the north pole and the upper magnetic pole piece 16 is the south pole.

Next, the operation of this embodiment will be explained.

The operation of the SOR device is as explained in FIG. As shown in Figure 2, the deflection section of the vacuum container 2, 2 a-C-
Assume that the electron beam 12 moves horizontally from the plane of the paper, and that the magnetic flux passing through the air gap between the magnetic poles 16 and 17 acts in such a way that the lower magnetic pole 17 is directed toward the upper magnetic pole 16 as shown. In this case, the distance d inside the deflection curvature in the radial direction
6 formed so that + is smaller than the outer opening do
An electron stably orbiting around the center is subject to the Lorentz force q
-Bz-v (q: electric charge, Bz: perpendicular magnetic flux density, V: velocity) and the inertial force due to acceleration in the radius r direction -v2/ρ (ρ: radius of parallel activation) are balanced, so ρ On the other hand, the force acting on an electron shifted from the center orbit becomes ρ r ρ ρ r ρ if we create a magnetic field distribution such that Bz(ρ) ρ, and when r>ρ, ΔF<O and the electron is inside When r is ρ, ΔF>O, and the electron is externally subjected to a force F.

Therefore, the electron beam 12 is converged while being deflected by the deflection section 2a.

Since the electron beam 2 is deflected and focused by the deflection section 2a in this manner, the adjustment of the focusing force using horizontal electromagnets as in the conventional method is not required, and its control becomes easy.

[Effects of the Invention] As is clear from the above explanation, the present invention exhibits the following excellent effects.

(1) By making the spacing between the S poles of the core different in the direction of the radius of deflection curvature, the electron beam can be deflected and focused at the same time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the present invention, FIG. 2 is a detailed cross-sectional view explaining the action of the bending electromagnet in the present invention, FIG. It is an explanatory diagram when converging an electron beam in an SOR device. In the figure, 1 is a synchrotron, 2 is a vacuum vessel, 2a is a deflection section, 4 is a deflection electromagnet, 12 is an electron beam, 15 is a core,
16 and 17 are magnetic poles, and 18 is a coil. Figure 1 Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Representative patent attorney Nobuo Kinutani (1 other person) Figure 2

Claims (1)

[Claims] 1. An SO equipped with a vacuum vessel in which an electron beam circulates, and a deflection electromagnet in which the deflection part of the vacuum vessel is positioned between the magnetic poles of a core around which a deflection coil is wound.
An SOR device characterized in that, in the R device, the spacing between the magnetic poles of the core is made different in order to provide a magnetic field distribution in the direction of the deflection curvature radius of the electron beam.