Catadioptric projection objective

US7385756B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• David Shafer · Fairfield, US
• Wilhelm Ulrich · Aalen, DE
• Aurelian Dodoc · Heidenheim an der Brenz, DE
• Rudolf Von Buenau · Jena, DE
• Hans-Juergen Mann · Oberkochen, DE
• Alexander Epple · Aalen, DE

Key dates

• Filing date: Jan 14, 2005
• Grant date: Jun 10, 2008
• Expiry date: Jan 14, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B13/22
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A catadioptric projection objective for imaging a pattern provided in an object plane of the projection objective onto an image plane of the projection objective comprises: a first objective part for imaging the pattern provided in the object plane into a first intermediate image; a second objective part for imaging the first intermediate imaging into a second intermediate image; a third objective part for imaging the second intermediate imaging directly onto the image plane; wherein a first concave mirror having a first continuous mirror surface and at least one second concave mirror having a second continuous mirror surface are arranged upstream of the second intermediate image; pupil surfaces are formed between the object plane and the first intermediate image, between the first and the second intermediate image and between the second intermediate image and the image plane; and all concave mirrors are arranged optically remote from a pupil surface. The system has potential for very high numerical apertures at moderate lens material mass consumption.