Projection objective for microlithography
AssigneeCarl-Zeiss-Stiftung
InventorKarl-Heinz Schuster
Life of this patent
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Abstract
The invention relates to a projection lens comprising a lens assembly that has at least one first narrowing of the group of light beams. A lens with a non-spherical surface is located in front of and/or behind the first narrowing.
Claims33
A projection objective for microlithography having a lens arrangement comprising:
- a first lens group having positive power;
- a second lens group having negative power;
- a third lens group having positive power;
- a fourth lens group having negative power;
- a fifth lens group having positive power;
- and
- a sixth lens group having positive power;
- wherein a lens at the end of said second lens group, or a lens at the beginning of said third lens group, has an aspheric surface.
A projection objective having a lens arrangement having at least a first waist of a pencil of rays, wherein said lens arrangement comprises at least one of the following:
- a lens having an aspheric surface arranged before said first waist,
- a lens having an aspheric surface arranged after said first waist, and
- lenses having aspheric surfaces arranged before and after said first waist.
A refractive microlithographic projection objective, having a lens arrangement comprising at least one lens with an aspheric lens surface, wherein all aspheric lens surfaces have a vertex radius (R) of at least 300 mm.
Dependencies are inferred from the claim text.