Optical system for ultraviolet light

US7256932B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Alexander Epple · Aalen, DE
• Toralf Gruner · Hennef (Sieg), DE
• Wolfgang Singer · Aalen, DE

Key dates

• Filing date: Oct 19, 2005
• Grant date: Aug 14, 2007
• Expiry date: Oct 19, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B17/0812
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An optical system for ultraviolet light having wavelengths λ≦200 nm, which may be designed in particular as a catadioptric projection objective for microlithography, has a plurality of optical elements including optical elements made of synthetic quartz glass or a fluoride crystal material transparent to a wavelength λ≦200 nm. At least two of the optical elements are utilized for forming at least one liquid lens group including a first delimiting optical element, a second delimiting optical element, and a liquid lens, which is arranged in an interspace between the first delimiting optical element and the second delimiting optical element and contains a liquid transparent to ultraviolet light having wavelengths λ≦200 nm. This enables effective correction of chromatic aberrations even in the case of systems that are difficult to correct chromatically.