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US 7,071,476 B2Granted
Illumination system with a plurality of light sources
AssigneeCarl Zeiss SMT GmbH
InventorsDirk Rothweiler, Jörg Schultz
Life of this patent
Estimating the term…
Abstract
There is provided an illumination system for EUV-wavelengths. The illumination system includes a plurality of EUV-light sources and an optical unit combining the plurality of EUV-light sources.
Claims43
An illumination system for EUV-wavelengths, comprising:
- a plurality of primary EUV-light sources from which a plurality of light paths originates;
- and
- an optical unit, situated in said plurality of light paths, that combines light from said plurality of EUV-light sources.
An illumination system for wavelengths ≦193 nm, comprising:
- a plurality of primary light sources;
- and
- an optical unit that combines light from said plurality of primary light sources so that an increase of intensity is achieved.
An illumination system having a first Lagrange optical invariant for wavelengths ≦193 nm, comprising:
- a plurality of primary light sources, wherein each of said plurality of primary light sources has a second Lagrange optical invariant;
- and
- an optical unit that combines light from said plurality of primary light sources so that a sum of said second Lagrange optical invariants is less than or equal to said first Lagrange optical invariant.
A projection exposure apparatus comprising:
- an illumination system for wavelengths ≦193 nm, wherein said illumination system comprises a plurality of primary light sources and an optical unit;
- a plane illuminated by said illumination system for accommodating a mask;
- a projection objective lens, wherein said optical unit combines light from said plurality of primary light sources so that a pupil of said projection objective lens is illuminated up to a predetermined degree of filing;
- and
- a carrier system for accommodating a light-sensitive object, wherein an image of said mask is formed on said light-sensitive object.
2 more elements
An illumination system for EUV-wavelengths, comprising:
- a plurality of EUV-light sources;
- an optical unit that combines light from said plurality of EUV-light sources;
- a plurality of raster elements, situated in a light path downstream of said optical unit, for producing secondary light sources,
- wherein said plurality of raster elements is imaged into a field plane to form a plurality of images that are superimposed to form an illuminated field.
1 more element
An illumination system for wavelengths ≦193 nm, comprising:
- a plurality of primary light sources, wherein each of said plurality of primary light sources has a Lagrange optical invariant;
- and
- an optical unit that combines light from said plurality of primary light sources so that a total Lagrange optical invariant is achieved being less than or equal to a Lagrange optical invariant of said illumination system.
Dependencies are inferred from the claim text.