EUV light generator

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)