Method for operating a projection exposure tool and control apparatus

US9310693B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Michael Gerhard · Aalen, DE
• Bernd Doerband · Aalen, DE
• Toralf Gruner · Hennef (Sieg), DE

Key dates

• Filing date: Mar 1, 2013
• Grant date: Apr 12, 2016
• Expiry date: Oct 7, 2033

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70891
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method for operating a projection exposure tool for microlithography is provided. The projection exposure tool includes an optical system which includes a number of optical elements which, during an imaging process, convey electromagnetic radiation. All of the surfaces of the optical elements interact with the electromagnetic radiation during the imaging process to form an overall optical surface of the optical system. The method includes: determining respective individual thermal expansion coefficients at least two different locations of the overall optical surface; calculating a change to an optical property of the optical system brought about by heat emission of the electromagnetic radiation (during the imaging process upon the basis of the thermal expansion coefficients; and imaging mask structures into an image plane via the projection exposure tool with adaptation of the imaging characteristics of the projection exposure tool so that the calculated change to the optical property is at least partially compensated.