Collector for EUV light source
View Patent ↗An apparatus/method is disclosed that may comprise an EUV light source which may comprise a collector which may comprise an elliptical collector mirror having a first focus at a plasma initiation point and a second focus at an intermediate focus of the EUV light source; a debris shield intermediate the plasma initiation point and the elliptical collector mirror comprising a plurality of radially extending channels extending from the first focus and aligned to the second focus and in symmetry about an axis of rotation passing through the first focus and aligned to a longitudinal axis of the elliptical collector mirror. The plurality of channels may be formed between a plurality of generally planer foils extending radially from the first focus and aligned to the second focus and in symmetry about an axis of rotation passing through the first focus and aligned to a longitudinal axis of the collector mirror.
1. An apparatus comprising:
an EUV light source comprising:
a collector comprising:
an elliptical collector mirror having a first focus at a plasma initiation point and a second focus at an intermediate focus of the EUV light source;
a debris shield intermediate the plasma initiation point and the elliptical collector mirror comprising a plurality of radially extending channels extending from the first focus and aligned to the second focus and in symmetry about an axis of rotation passing through the first focus and aligned to a longitudinal axis of the elliptical collector mirror.
2. The apparatus of claim 1 wherein:
the plurality of channels are formed between a plurality of generally planer foils extending radially from the first focus and aligned to the second focus and in symmetry about an axis of rotation passing through the first focus and aligned to a longitudinal axis of the collector mirror.
3. The apparatus of claim 2 wherein:
the elliptical collecting mirror comprising an aperture centered on the longitudinal axis of the elliptical collector mirror permitting irradiation of the plasma initiation point with a laser beam.
4. The apparatus of claim 3 further comprising:
a first collecting mirror comprising an elliptical reflecting surface having a first focus at a plasma ignition point;
a second collecting mirror comprising a section of a spherical mirror having a center at the plasma initiation point and disposed to collect light not striking the first collecting mirror and reflecting such light onto the first collecting mirror focused through the first focus of the first collecting mirror.
5. The apparatus of claim 4 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
6. The apparatus of claim 4 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
7. The apparatus of claim 4 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
8. The apparatus of claim 4 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
9. The apparatus of claim 3 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
10. The apparatus of claim 3 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
11. The apparatus of claim 3 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
12. The apparatus of claim 3 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
13. The apparatus of claim 2 further comprising:
a first collecting mirror comprising an elliptical reflecting surface having a first focus at a plasma ignition point;
a second collecting mirror comprising a section of a spherical mirror having a center at the plasma initiation point and disposed to collect light not striking the first collecting mirror and reflecting such light onto the first collecting mirror focused through the first focus of the first collecting mirror.
14. The apparatus of claim 13 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
15. The apparatus of claim 13 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
16. The apparatus of claim 13 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
17. The apparatus of claim 13 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
18. The apparatus of claim 2 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
19. The apparatus of claim 2 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
20. The apparatus of claim 2 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
21. The apparatus of claim 2 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
22. The apparatus of claim 1 wherein:
the elliptical collecting mirror comprising an aperture centered on the longitudinal axis of the elliptical collector mirror permitting irradiation of the plasma initiation point with a laser beam.
23. The apparatus of claim 22 further comprising:
a first collecting mirror comprising an elliptical reflecting surface having a first focus at a plasma ignition point;
a second collecting mirror comprising a section of a spherical mirror having a center at the plasma initiation point and disposed to collect light not striking the first collecting mirror and reflecting such light onto the first collecting mirror focused through the first focus of the first collecting mirror.
24. The apparatus of claim 23 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
25. The apparatus of claim 23 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
26. The apparatus of claim 23 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
27. The apparatus of claim 23 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
28. The apparatus of claim 22 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
29. The apparatus of claim 22 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
30. The apparatus of claim 22 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
31. The apparatus of claim 22 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
32. The apparatus of claim 1 further comprising:
a first collecting mirror comprising an elliptical reflecting surface having a first focus at a plasma ignition point;
a second collecting mirror comprising a section of a spherical mirror having a center at the plasma initiation point and disposed to collect light not striking the first collecting mirror and reflecting such light onto the first collecting mirror focused through the first focus of the first collecting mirror.
33. The apparatus of claim 32 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
34. The apparatus of claim 32 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
35. The apparatus of claim 32 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
36. The apparatus of claim 32 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.
37. The apparatus of claim 1 further comprising:
photons of EUV light produced at the plasma initiation point pass through a respective channel in the debris shield on the way to a reflecting coating on the collector mirror and return to a second focus of the elliptical collector mirror at the intermediate focus of the EUV light source through the same channel.
38. The apparatus of claim 1 further comprising:
a plasma source material delivery mechanism:
the collector mirror extending to a point that does not block the delivery of target material to the plasma initiation point.
39. The apparatus of claim 1 further comprising:
a plasma source material delivery mechanism:
the collector mirror comprising an opening for the delivery of plasma source material to the plasma initiation point.
40. The apparatus of claim 1 further comprising:
the collector mirror debris shield comprising an aperture centered on a common longitudinal axis of the elliptical collector mirror and the debris shield permitting irradiation of the plasma initiation point with a laser beam.