Catadioptric reduction lens

US7136220B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Wilhelm Ulrich · Aalen, DE
• David Shafer · Fairfield, US
• Alexander Epple · Aalen, DE
• Helmut Beierl · Heidenheim, DE
• Aurelian Dodoc · Heidenheim an der Brenz, DE

Key dates

• Filing date: Mar 22, 2004
• Grant date: Nov 14, 2006
• Expiry date: Mar 22, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70275
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A catadioptric projection lens for imaging a pattern arranged in an object plane onto an image plane, preferably while creating a real intermediate image, including a catadioptric first lens section having a concave mirror and a physical beamsplitter having a beamsplitting surface, as well as a second lens section that is preferably refractive and follows the beamsplitter, between its object plane and image plane. Positive refractive power is arranged in an optical near-field of the object plane, which is arranged at a working distance from the first optical surface of the projection lens. The beamsplitter lies in the vicinity of low marginal-ray heights, which allows configuring projection lenses that are fully corrected for longitudinal chromatic aberration, while employing small quantities of materials, particularly those materials needed for fabricating their beamsplitters.