Method of operating a microlithographic projection exposure apparatus and projection objective of such an apparatus

US9164402B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Holger Walter · Aalen, DE
• Boris Bittner · Roth, DE

Key dates

• Filing date: Jul 10, 2014
• Grant date: Oct 20, 2015
• Expiry date: Jul 10, 2034

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70308
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection objective of a microlithographic projection exposure apparatus has a wavefront correction device including a first refractive optical element and a second refractive optical element. The first refractive optical element includes a first optical material having, for an operating wavelength of the apparatus, an index of refraction that decreases with increasing temperature. The second refractive optical element includes a second optical material having, for an operating wavelength of the apparatus, an index of refraction that increases with increasing temperature. In a correction mode of the correction device, a first heating device produces a non-uniform and variable first temperature distribution in the first optical material, and a second heating device produces a non-uniform and variable second temperature distribution in the second optical material.