EUV light generator

Patent metadata

Field	Value
Publication number	US-10863613-B2
Application number	US-201916560611-A
Country	US
Kind code	B2
Filing date	Sep 4, 2019
Priority date	Apr 26, 2017
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

An EUV light generator including the following components: A. an electron storage ring including a first linear section and a second linear section; B. an electron supplier configured to supply the electron storage ring with an electron bunch; C. a high-frequency acceleration cavity disposed in the first linear section and configured to accelerate the electron bunch in such a way that a length Lez of the electron bunch satisfies “0.09 m≤Lez≤3 m;” and D. an undulator disposed in the second linear section and configured to output EUV light when the electron bunch enters the undulator.

First claim

What is claimed is:

1. An EUV light generator comprising:
an electron storage ring including a first linear section and a second linear section;
an electron supplier configured to supply the electron storage ring with an electron bunch;
a high-frequency acceleration cavity disposed in the first linear section and configured to accelerate the electron bunch in such a way that a length Lez of the electron bunch satisfies Expression (a) below:
0.09 m≤Lez ≤3 m   (a); and

an undulator disposed in the second linear section and configured to output EUV light when the electron bunch enters the undulator,
wherein the electron supplier includes:
a pulsed laser apparatus configured to output pulsed laser light;
light collection optics configured to collect the pulsed laser light; and
a photocathode configured to generate the electron bunch when the pulsed laser light collected by the light collection optics is incident on the photocathode; and

wherein a collected light diameter D L of the pulsed laser light on a surface of the photocathode satisfies Expression (g) below;
300μm D L ≤6000μm   (g).

2. The EUV light generator according to claim 1 ,
wherein the high-frequency acceleration cavity accelerates the electron bunch in such a way that the length Lez of the electron bunch satisfies Expression (b) below:
0.09 m≤Lez ≤0.9 m   (b).

3. The EUV light generator according to claim 2 ,
wherein the high-frequency acceleration cavity includes a plurality of cell cavities having substantially a same length, and
a length La of each of the cell cavities satisfies Expression (c) below:
0.18 m≤La ≤1.8 m   (c).

4. The EUV light generator according to claim 2 ,
wherein a current value of the electron bunch circulating through the electron storage ring ranges from 10 to 20 A.

5. The EUV light generator according to claim 1 ,
wherein a length L of the undulator satisfies Expression (d) below:
15 m≤L ≤30 m   (d).

6. The EUV light generator according to claim 1 ,
wherein a pulse width Wp of the pulsed laser light satisfies Expression (e) below:
0.3 ns≤Wp ≤10 ns   (e).

7. The EUV light generator according to claim 1 ,
wherein a pulse width Wp of the pulsed laser light satisfies Expression (f) below:
0.3 ns≤Wp≤ 3 ns   (f).

8. The EUV light generator according to claim 1 ,
wherein a collected light diameter D L of the pulsed laser light on a surface of the photocathode satisfies Expression (h) below:
600 μm≤D L ≤3000 μm (h).

9. The EUV light generator according to claim 1 ,
wherein the light collection optics includes a light collection lens and a linear stage that holds the light collection lens and moves the light collection lens along an optical axis of the light collection optics, and
a collected light diameter of the pulsed laser light on a surface of the photocathode is adjustable by controlling the linear stage to move the light collection lens.

10. The EUV light generator according to claim 1 ,
wherein the high-frequency acceleration cavity disposed in the first linear section and configured to accelerate the electron bunch and include a plurality of cell cavities having substantially a same length, with a length La of each of the cell cavities satisfying Expression (k) below:
0.18 m≤La ≤6 m   (k).

11. An EUV light generator comprising:
an electron storage ring including a first linear section and a second linear section;
an electron supplier configured to supply the electron storage ring with an electron bunch;
a high-frequency acceleration cavity disposed in the first linear section and configured to accelerate the electron bunch in such a way that a length Lez of the electron bunch satisfies Expression (a) below:
0.09 m≤Lez ≤3 m   (a); and

an undulator disposed in the second linear section and configured to output EUV light when the electron bunch enters the undulator,
wherein the electron supplier includes:
a pulsed laser apparatus configured to output pulsed laser light,
light collection optics configured to collect the pulsed laser light, and
a photocathode configured to generate the electron bunch when the pulsed laser light collected by the light collection optics is incident on the photocathode,

wherein the light collection optics includes a wavefront adjuster configured to adjust a shape of a wavefront of the pulsed laser light output from the pulsed laser apparatus, and
wherein a collected light diameter of the pulsed laser light on a surface of the photocathode is adjustable by controlling the wavefront adjuster to adjust the shape of the wavefront.

12. The EUV light generator according to claim 11 ,
wherein the wavefront adjuster includes a convex lens and a concave lens disposed along an optical axis of the pulsed laser light, and
adjusting a gap between the convex lens and the concave lens allows adjustment of the collected light diameter.

13. The EUV light generator according to claim 12 ,
wherein the light collection optics includes a linear stage configured to hold and move one of the convex lens and the concave lens.

14. An EUV light generator comprising:
an electron storage ring including a first linear section and a second linear section;
an electron supplier configured to supply the electron storage ring with an electron bunch; a high-frequency acceleration cavity disposed in the first linear section and configured to accelerate the electron bunch in such a way that a length Lez of the electron bunch satisfies Expression (a) below:
0.09 m≤Lez≤ 3 m   (a); and

an undulator disposed in the second linear section and configured to output EUV light when the electron bunch enters the undulator, wherein a diameter D B of the electron bunch in a direction perpendicular to a traveling direction of the electron hunch satisfies Expression (i) below:
300 μm≤ D B ≤6000μm   (i)

15. The EUV light generator according to claim 14 ,
wherein a diameter D B of the electron bunch in a direction perpendicular to a traveling direction of the electron bunch satisfies Expression (j) below:
600μm≤ D B ≤3000μm   (j)

Assignees

• Gigaphoton Inc

Inventors

• Okazaki Shinji
• Wakabayashi Osamu

Classifications

• H05H7/06 Primary

  Two-beam arrangements; Multi-beam arrangements {storage rings}; Electron rings · CPC title

• H05H2007/041

  for beam bunching, e.g. undulators · CPC title

• G03F7/70033

  by plasma extreme ultraviolet [EUV] sources · CPC title

• H05H7/04

  Magnet systems {, e.g. undulators, wigglers (free-electron laser H01S3/0903)}; Energisation thereof · CPC title

• H05H2007/046

  for beam deflection · CPC title