Illumination optical system for projection lithography

US9110378B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Jens Ossmann · Aalen, DE
• Martin Endres · Oberkochen, DE
• Ralf Stuetzle · Aalen, DE

Key dates

• Filing date: May 14, 2013
• Grant date: Aug 18, 2015
• Expiry date: Oct 18, 2033

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70058
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An illumination optical system for projection lithography has an optical assembly for guiding illumination light to an object field to be illuminated in an object plane. The illumination optical system divides a bundle of the illumination light into a plurality of part bundles, which are allocated to various illumination directions of the object field illumination. The illumination optical system is configured in such a way that at least some of the part bundles are superimposed on one another in a first superimposition plane according to a first superimposition specification and in a second superimposition plane, which is spaced apart from the first superimposition plane, according to a second superimposition specification. The result is an illumination optical system, in which an influencing and/or a monitoring of an illumination intensity distribution over the object field is made possible, as far as possible without influencing an illumination angle distribution.