Projection objective

US7557902B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Udo Dinger · Oberkochen, DE
• Frank Eisert · Aalen, DE
• Stefan Koehler · Eppelheim, DE
• Andreas Ochse · Oberkochen, DE
• Johannes Zellner · Aalen, DE
• Martin Lowisch · Oberkochen, DE
• Timo Laufer · Stuttgart, DE

Key dates

• Filing date: Sep 27, 2003
• Grant date: Jul 7, 2009
• Expiry date: Mar 3, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G21K2201/065
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection objective 1 for short wavelengths, in particular for wavelengths λ<157 nm is provided with a number of mirrors [M1, M2, M3, M4, M5 and M6] that are arranged positioned precisely in relation to an optical axis 5. The mirrors [M1, M2, M3, M4, M5 and M6] have multilayer coatings. At least two different mirror materials are provided which differ in the rise in the coefficient of thermal expansion as a function of temperature in the region of the zero crossing of the coefficients of thermal expansion, in particular in the sign of the size.