Apparatus and method for characterizing a microlithographic mask

US11914303B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Johannes Ruoff · Aalen, DE
• Heiko Feldmann · Aalen, DE
• Ulrich Matejka · Jena, DE
• Thomas Thaler · Jena, DE
• Sascha Perlitz · Jena, DE
• Shao-Chi Wei · Hsinchu, TW
• Joerg Frederik Blumrich · Jena, DE
• Markus Deguenther · Aalen, DE

Key dates

• Filing date: Jun 11, 2021
• Grant date: Feb 27, 2024
• Expiry date: Mar 4, 2042

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/95676
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The invention relates to an apparatus and a method for characterizing a microlithographic mask. According to one aspect, an apparatus according to the invention comprises at least one light source which emits coherent light, an illumination optical unit which produces a diffraction-limited light spot on the mask from the coherent light of the at least one light source, a scanning device, by use of which it is possible to implement a scanning movement of the diffraction-limited light spot relative to the mask, a sensor unit, and an evaluation unit for evaluating the light that is incident on the sensor unit and has come from the mask, an output coupling element for coupling out a portion of the coherent light emitted by the at least one light source, and an intensity sensor for capturing the intensity of this output coupled portion.