Radiation source

Patent metadata

Field	Value
Publication number	US-9632419-B2
Application number	US-201214346530-A
Country	US
Kind code	B2
Filing date	Aug 23, 2012
Priority date	Sep 22, 2011
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A radiation source having a fuel stream generator ( 110 ) that generates and directs a fuel stream ( 102 ) along a trajectory towards a plasma formation location ( 104 ). A pre-pulse laser radiation assembly directs a first beam of laser radiation ( 100 ) at the fuel stream at the plasma formation location to generate a modified fuel target ( 106 ). A main pulse laser radiation assembly directs a second beam of laser radiation ( 108 ) at the modified fuel target at the plasma formation location to generate a radiation generating plasma ( 117 ). A collector ( 122 ) collects the radiation and directs it along an optical axis ( 105 ) of the radiation source. The first beam of laser radiation being directed toward the fuel stream substantially along the optical axis.

First claim

The invention claimed is:

1. A radiation source comprising:
a fuel stream generator configured to:
generate a fuel stream, and
direct the fuel stream along a trajectory towards a plasma formation location;

a pre-pulse laser radiation assembly configured to:
direct a first beam of laser radiation at the fuel stream at the plasma formation location substantially along an optical axis of the radiation source, and
generate a modified fuel target comprising a desired shape and orientation;

a main pulse laser radiation assembly configured to:
direct a second beam of laser radiation at the modified fuel target at the plasma formation location substantially at an angle greater than 0 degrees and less than 90 degrees with respect to the optical axis, and
generate a radiation generating plasma,
wherein the desired shape and orientation of the modified fuel target ensures reflection of a portion of the second beam of laser radiation, unused by the modified fuel target in generation of the radiation generating plasma, from the modified fuel target; and

a grazing incidence collector configured to:
collect radiation generated by the radiation generating plasma; and
direct the collected radiation along the optical axis.

2. The radiation source of claim 1 , wherein the main pulse laser radiation assembly is configured to direct the second beam of laser radiation towards a side of the modified fuel target facing away from the grazing incidence collector.

3. The radiation source of claim 1 , wherein the main pulse laser radiation assembly is configured to direct the second beam of laser radiation towards a side of the modified fuel target facing the grazing incidence collector.

4. The radiation source of claim 1 , wherein:
the main pulse laser radiation assembly is configured to direct the second beam of laser radiation in a direction towards the grazing incidence collector; and
the grazing incidence collector comprises an aperture configured to allow passage to at least a portion of the second beam of laser radiation that is not incident on the fuel stream or the modified fuel target.

5. The radiation source of any of claim 1 , wherein the pre-pulse laser radiation assembly is configured to direct the first beam of laser radiation, along the optical axis of the radiation source, in a propagation direction of the radiation generated by the radiation generating plasma.

6. The radiation source of claim 1 , wherein the pre-pulse laser radiation assembly is configured to direct the first beam of laser radiation towards the grazing incidence collector, along the optical axis of the radiation source, in an opposite direction to a propagation direction of the radiation generated by the radiation generating plasma.

7. The radiation source of any of claim 1 , wherein:
the grazing incidence collector is located between the plasma formation location and a focal point of the grazing incidence collector; and
the pre-pulse laser radiation assembly is configured to direct the first beam of laser radiation through the grazing incidence collector, along the optical axis of the radiation source, in an opposite direction to a propagation direction of the radiation generated by the radiation generating plasma and collected by the grazing incidence collector.

8. The radiation source of any of claim 1 , wherein:
the grazing incidence collector is located between the plasma formation location and a focal point of the grazing incidence collector; and
the pre-pulse laser radiation assembly is configured to direct the first beam of laser radiation towards the grazing incidence collector, along the optical axis of the radiation source, in a propagation direction of the radiation generated by the radiation generating plasma and collected by the grazing incidence collector.

9. The radiation source of claim 1 , wherein:
the pre-pulse laser radiation assembly is configured to ensure that the modified fuel target comprises a substantially disc shaped cloud after being hit by the first beam of laser radiation; and
the disc shaped cloud comprises a radius substantially perpendicular with respect to the optical axis.

10. A lithographic apparatus comprising, or in connection with, a radiation source, the radiation source comprising:
a fuel stream generator configured to:
generate a fuel stream, and
direct the fuel stream along a trajectory towards a plasma formation location;

a pre-pulse laser radiation assembly configured to:
direct a first beam of laser radiation at the fuel stream at the plasma formation location substantially along an optical axis of the radiation source, and
generate a modified fuel target comprising a desired shape and orientation;

a main pulse laser radiation assembly configured to:
direct a second beam of laser radiation at the modified fuel target at the plasma formation location substantially at an angle greater than 0 degrees and less than 90 degrees with respect to the optical axis, and
generate a radiation generating plasma,
wherein the desired shape and orientation of the modified fuel target ensures reflection of a portion of the second beam of laser radiation, unused by the modified fuel target in generation of the radiation generating plasma, from the modified fuel target; and

a grazing incidence collector configured to:
collect radiation generated by the radiation generating plasma; and
direct the collected radiation along the optical axis.

11. A radiation source comprising:
a fuel stream generator configured to:
generate a fuel stream, and
direct the fuel stream along a trajectory towards a plasma formation location;

a pre-pulse laser radiation assembly configured to:
direct a first beam of laser radiation at the fuel stream at the plasma formation location substantially along an optical axis of the radiation source, and
generate a modified fuel target comprising a desired shape and orientation;

a main pulse laser radiation assembly configured to:
direct a second beam of laser radiation at the modified fuel target at the plasma formation location, and
generate a radiation generating plasma,
wherein the desired shape and orientation of the modified fuel target ensures reflection of a portion of the second beam of laser radiation, unused by the modified fuel target in generation of the radiation generating plasma, from the modified fuel target; and

a grazing incidence collector, located downstream of the radiation generating plasma, configured to:
collect radiation generated by the radiation generating plasma; and
direct the collected radiation along the optical axis of the radiation source.

12. The radiation source of claim 11 , further comprising a debris mitigation arrangement, located between the plasma formation location and the grazing incidence collector, comprising a stationary or rotatable foil trap; and
wherein the pre-pulse laser radiation assembly or the main pulse laser radiation assembly is configured to direct the first or second beam of laser radiation, respectively, along and through a hollow axis of the debris mitigation arrangement.

13. The radiation source of claim 11 , wherein the main pulse laser radiation assembly is configured to direct the second beam of laser radiation towards the modified fuel target substantially along the optical axis, and in the same direction to that of the first beam of radiation.

14. The radiation source of claim 11 , wherein the main pulse laser radiation assembly is configured to direct the second beam of laser radiation towards the modified fuel target substantially along the optical axis, and in an opposite direction to t

Assignees

• Van Schoot Jan Bernard Plechelmus
• Banine Vadim Yevgenyevich
• Frijns Olav Waldemar Vladimir
• Kreuwel Hermanus
• Moors Johannes Hubertus Josephina
• Stamm Uwe Bruno Heini
• Swinkels Gerardus Hubertus Petrus Maria
• Vanderhallen Ivo
• Yakunin Andrei Mikhailovich
• Asml Netherlands Bv

Inventors

• Van Schoot Jan Bernard Plechelmus
• Banine Vadim Yevgenyevich
• Frijns Olav Waldemar Vladimir
• Kreuwel Hermanus
• Moors Johannes Hubertus Josephina
• Stamm Uwe Bruno Heini
• Swinkels Gerardus Hubertus Petrus Maria
• Vanderhallen Ivo
• Yakunin Andrei Mikhailovich

Classifications

• H05G2/0088

  for preconditioning the plasma generating material · CPC title

• H05G2/009

  Auxiliary arrangements not involved in the plasma generation · CPC title

• H05G2/008

  involving an energy-carrying beam in the process of plasma generation · CPC title

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/70058 Primary

  Mask illumination systems · CPC title