Method for determining a focus position of a lithography mask and metrology system for carrying out such a method

US10564551B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Markus Koch · Neu-Ulm, DE
• Dirk Hellweg · Langenau, DE
• Renzo Capelli · Heidenheim, DE
• Martin Dietzel · Giengen an der Brenz, DE

Key dates

• Filing date: Feb 20, 2019
• Grant date: Feb 18, 2020
• Expiry date: Feb 20, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F9/7026
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

For determining a focus position of a lithography mask (e.g., 5), a focus stack of a measurement region free of structures to be imaged is recorded and the speckle patterns of the recorded images are evaluated.