Beam Homogenizer, Illumination System and Metrology System
AssigneesASML Netherlands B.V., ASML Holding N.V.
InventorsMarkus Franciscus Antonius EURLINGS, Armand Eugene Albert Koolen, Teunis Willem Tukker, Johannes Matheus Marie De Wit, Stanislav Smirnov
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Abstract
A beam homogenizer for homogenizing a beam of radiation and an illumination system and metrology apparatus comprising such a beam homogenizer as provided. The beam homogenizer comprises a filter system having a controllable radial absorption profile and configured to output a filtered beam and an optical mixing element configured to homogenize the filtered beam. The filter system may be configured to homogenize the angular beam profile radially and said optical mixing element may be configured to homogenize the angular beam profile azimuthally.
Claims20
A beam homogenizer for homogenizing a beam of radiation comprising:
- a filter system comprising a controllable radial absorption profile and configured to output a filtered beam;
- and
- an optical mixing element configured to homogenize the filtered beam.
An illumination system configured to illuminate a structure on a substrate with measurement radiation, the illumination system comprising:
- a beam homogenizer configured to homogenize a beam of radiation comprising:
- a filter system comprising a controllable radial absorption profile and configured to output a filtered beam;
- and
- an optical mixing element configured to homogenize the filtered beam;
- wherein the beam homogenizer is operable to control beam homogenization of the measurement radiation.
A metrology apparatus comprising:
- an illumination system configured to illuminate a structure on a substrate with measurement radiation, the illumination system comprising:
- a beam homogenizer configured to homogenize a beam of radiation comprising:
- a filter system comprising a controllable radial absorption profile and configured to output a filtered beam;
- and
- an optical mixing element configured to homogenize the filtered beam;
- wherein the beam homogenizer is operable to control beam homogenization of the measurement radiation;
- and
- a detection system configured to detect scattered radiation arising from illumination of the structure.
Dependencies are inferred from the claim text.