Method and device for characterizing a mask for microlithography

US11188000B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Michael Kamp-Froese · Aalen, DE
• Markus Koch · Neu-Ulm, DE
• Tobias Mueller · Gelnhausen, DE

Key dates

• Filing date: May 14, 2020
• Grant date: Nov 30, 2021
• Expiry date: May 14, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70558
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method and a device for characterizing a mask for microlithography in a characterization process carried out using an optical system, wherein the optical system includes an illumination optical unit and an imaging optical unit and wherein in the characterization process structures of the mask are illuminated by the illumination optical unit, the mask is imaged onto a detector unit by the imaging optical unit and image data recorded by the detector unit are evaluated in an evaluation unit. A method includes the following steps: determining a temporal variation of at least one variable that is characteristic of the thermal state of the optical system, and modifying the characterization process depending on the temporal variation determined.