Illumination optical unit for a metrology system and metrology system comprising such an illumination optical unit

US10578881B2 · kind B2 · utility

Assignees

• Carl Zeiss AG · DE
• Carl Zeiss SMT GmbH · DE

Inventors

• Thomas Frank · Lake Geneva, US
• Dirk Doering · Erfurt, DE
• Holger Seitz · Jena, DE
• Mario Laengle · Jena, DE
• Ulrich Matejka · Jena, DE

Key dates

• Filing date: Dec 14, 2018
• Grant date: Mar 3, 2020
• Expiry date: Dec 14, 2038

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F1/84
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An illumination optical unit serves for illuminating objects to be examined by a metrology system. The illumination optical unit has an optical pupil shaping assembly for generating a defined distribution of illumination angles of illumination light over an object field in which an object to be examined can be arranged. An optical field shaping assembly for generating a defined intensity distribution of the illumination light over the object field is disposed downstream of the pupil shaping assembly in the beam path of the illumination light. The field shaping assembly has at least one optical field shaping element arranged in the region of a pupil plane of the illumination optical unit. This results in an illumination optical unit which ensures an illumination which can be set in a defined manner with regard to an intensity distribution and an illumination angle distribution over the entire object field.