Measurement apparatus for measuring a wavefront aberration of an imaging optical system

US11441970B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Albrecht Ehrmann · Aalen, DE
• Helmut Haidner · Aalen, DE
• Michael Samaniego · Ulm, DE

Key dates

• Filing date: Aug 30, 2019
• Grant date: Sep 13, 2022
• Expiry date: Dec 11, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/706
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A measurement apparatus (10) for measuring a wavefront aberration of an imaging optical system (12) includes (i) a measurement wave generating module (24) which generates a measurement wave (26) radiated onto the optical system and which includes an illumination system (30) illuminating a mask plane (14) with an illumination radiation (32), as well as coherence structures (36) arranged in the mask plane, and (ii) a wavefront measurement module (28) which measures the measurement wave after passing through the optical system and determines from the measurement result, with an evaluation device (46), a deviation of the wavefront of the measurement wave from a desired wavefront. The evaluation device (46) determines an influence of an intensity distribution (70) of the illumination radiation in the region of the mask plane on the measurement result and, when determining the deviation of the wavefront, utilizes the influence of the intensity distribution.