Measurement method for interferometrically determining a surface shape

US12332043B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Hans-Michael Stiepan · Aalen, DE
• Sebastian Fuchs · Aalen, DE
• Jochen Hetzler · Aalen, DE

Key dates

• Filing date: Sep 22, 2021
• Grant date: Jun 17, 2025
• Expiry date: Mar 13, 2043

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B2290/30
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Measurement method for interferometrically determining a shape of a test object (14) surface (12) includes arranging a first diffractive optical element (30, 130, 230) in an input wave (18) beam path, to generate a first test wave (34) with a wavefront that is adapted to a desired shape of the optical surface, detecting a first interferogram generated by the first test wave after interaction with the test object surface, arranging a different diffractive optical element (32, 232) in the input wave beam path for generating a further test wave with a wavefront which is adapted to the desired shape of the optical surface, the first and the further diffractive optical elements differing in their respective diffraction structure configurations, capturing a further interferogram generated by the further test wave after interaction with the test object surface, and determining the surface shape of the test object by calculating the two interferograms.