Patent · US Active

Projection objective

US8902406B2 · kind B2 · utility

1Cited by

14References

28Claims

0Family size

Assignee

Carl Zeiss SMT GmbH · DE

Inventors

Reinhold Walser · Reinheim, DE
Thomas Schicketanz · Aalen, DE

Key dates

Filing date	Nov 22, 2010
Grant date	Dec 2, 2014
Priority date	—
Expiry date	Jul 10, 2032

Classification

Technology area (CPC G)Physics
CPC primaryG03F7/70316
WIPO fieldOptics
WIPO sectorInstruments

Abstract

A projection objective, such as for EUV lithography, for imaging a pattern arranged in an object plane into an image plane with the aid of electromagnetic radiation from the extreme ultraviolet range is provided. The projection objective includes a plurality of mirrors provided with reflective coatings and arranged between the object plane and the image plane. At least one of the mirrors includes a graded reflective coating with a rotationally-asymmetric coating thickness profile in the mirror plane on a substrate with a rotationally-asymmetric or rotationally-symmetric surface profile. The projection objective can exhibit increased overall transmission.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.