Refractive projection objective for immersion lithography

US7408716B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Hans-Juergen Rostalski · Oberkochen, DE
• Aurelian Dodoc · Heidenheim an der Brenz, DE
• Alexander Epple · Aalen, DE
• Helmut Beierl · Heidenheim, DE

Key dates

• Filing date: Jan 4, 2007
• Grant date: Aug 5, 2008
• Expiry date: Jan 4, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B27/0025
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A purely refractive projection objective suitable for immersion microlithography is designed as a single-waist system with five lens groups, in the case of which a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with negative refractive power, a fourth lens group with positive refractive power and a fifth lens group with positive refractive power are provided. A constriction site of narrowest constriction of the beam bundle lies in the region of the waist. A waist distance AT exists between the object plane and the constriction site X. The condition AT/L≦0.4 holds for a distance ratio AT/L between the waist distance AT and an object-image distance L of the projection objective. Embodiments of inventive projection objectives reach very high numerical apertures NA>1.1 in conjunction with a large image field and are distinguished by a compact overall size and good correction of the lateral chromatic aberration.