Optical attenuator device, radiation system and lithographic apparatus therewith and device manufacturing method

An optical attenuator device for improving a homogeneity of a beam of radiation for use in a lithographic apparatus, said optical attenuator device comprising at least one optical attenuator element which removes at least a part of said radiation from said beam of radiation, wherein said at least one optical attenuator element comprises a first mirror and a second mirror and a mirror actuator, wherein a slit is present between said first and second mirror, wherein at least one of mirror is movable with respect to the beam of radiation by the mirror actuator, so as to vary the slit width.

An optical attenuator device for improving a homogeneity of a beam of radiation for use in a lithographic apparatus, said optical attenuator device comprising at least one optical attenuator element which removes at least a part of said radiation from said beam of radiation, wherein said at least one optical attenuator element comprises a plurality of mutually parallel strips which are movable into the beam of radiation and which comprise a material which is between 10% and 100% transparent for said radiation.

A filter, comprising:

• a substrate having a surface;
• and
• an anti-reflection coating, wherein said anti-reflection coating is present on a central part of the filter, said central part of the filter extending in a longitudinal direction from one edge of the filter to an opposite edge of the filter and having a length in said longitudinal direction and a width in a direction perpendicular to the longitudinal direction, wherein said width vanes over said length, said central part of the filter having a homogeneous transmission of at least 90% for a predetermined type of radiation, wherein a transmission of said central part of the filter is greater than other parts of the filter.

A radiation system constructed and arranged to provide a beam of radiation with a homogeneous intensity distribution, comprising a source of radiation, a collector constructed and arranged to collect said radiation into the beam of radiation, an optical attenuator device comprising at least one optical attenuator element which removes at least a part of said radiation from said beam of radiation, and a mirror comprising a plurality of facets that are arranged in the beam of radiation, each facet constructed and arranged to reflect a part of the beam of radiation as a reflected partial beam, such that at least two of said reflected partial beams overlap at a predetermined distance from the mirror, wherein the optical attenuator element comprises at least one rod located between the collector and the mirror, wherein the rod extends in a direction perpendicular to the propagation direction of the beam of radiation.

An optical attenuator for use in a lithographic apparatus comprising:

• an attenuator element disposable in a radiation beam path of the lithographic apparatus, such that the attenuator element extends along a narrow, central region of the beam path, the attenuator element comprising a material having a transmissivity of less than 100% at a wavelength of radiation of the lithographic apparatus.