Projection illumination system for EUV microlithography
AssigneeCarl Zeiss SMT GmbH
InventorsUdo Dinger, Markus Hauf
Life of this patent
Estimating the term…
Abstract
A projection illumination installation for EUV microlithography includes an EUV synchrotron light source for producing EUV used light. An object field is illuminated with the used light using illumination optics. The object field is mapped into an image field using projection optics. A scanning device is used to illuminate the object field by deflecting the used light in sync with a projection illumination period. The result is a projection illumination installation in which the output power from an EUV synchrotron light source can be used as efficiently as possible for EUV projection illumination.
Claims28
An installation having an object field and an image field, the installation comprising:
- a light source configured to generate EUV light with a pulse frequency;
- illumination optics configured to illuminate the object field with the EUV light, the illumination optics comprising a field facet mirror comprising a plurality of field facets including a first field facet and a second field facet;
- projection optics configured to map the object field into the image field;
- and
- a scanning device configured to deflect the EUV light onto the field facet mirror so that, during use of the installation:
- a first pulse of EUV light illuminates the first field facet without illuminating the second field facet;
- and
- a second pulse of EUV light illuminates the second field facet without illuminating the first facet,
- wherein:
- the installation is an EUV microlithography projection illumination installation;
- the scanning device has a first axis and a second axis perpendicular to the first axis;
- and
- during use of the illumination optics:
- light deflected by the scanning device impinges the field facet mirror;
- rotation of the scanning device about its first axis advances EUV light deflected by the scanning device along the field facet mirror in a first direction;
- and
- rotation of the scanning device about its second axis advances the EUV light deflected by the scanning device along the field facet mirror in a second direction which is different from the first direction.
A method, comprising:
- using a light source to generate a plurality of pulses of EUV light including a first pulse of EUV light and a second pulse of EUV light;
- illuminating a first field facet of a field facet mirror with the first pulse of EUV light without illuminating a second field facet of the field facet mirror with the first pulse of EUV light, the field facet mirror being a component of an illumination optics of a microlithography projection illumination installation;
- illuminating the second field facet with the second pulse of EUV light without illuminating the first field facet with the second pulse of EUV light;
- and
- projecting the EUV light from an object plane of the microlithography projection illumination installation to an image plane of the microlithography projection illumination installation,
- wherein the method comprises:
- rotating a scanning device about first a first axis;
- and
- rotating the scanning device about a second axis which is different from the first axis;
- and
- wherein rotating the scanning device about its first axis advances the EUV light deflected by the scanning device along the field facet mirror in a first direction, and rotating the scanning device about its second axis advances the EUV light deflected by the scanning device along the field facet mirror in a second direction which is different from the first direction.
Dependencies are inferred from the claim text.