Imaging optical unit and projection exposure apparatus including same

US10527832B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Markus Schwab · Aalen, DE
• Hans-Juergen Rostalski · Oberkochen, DE

Key dates

• Filing date: Nov 17, 2017
• Grant date: Jan 7, 2020
• Expiry date: Nov 17, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/7025
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An imaging optical unit for projection lithography has a plurality of mirrors for imaging an object field into an image field with imaging light guided along a path from the object field to the image field. The penultimate mirror in the path has no passage opening to pass the imaging light. The imaging optical unit has a stop to predefine an outer marginal contour of a pupil of the imaging optical unit. The stop is between the penultimate and last mirrors in the path. The imaging optical unit can have exactly one stop for predefining at least one section of the outer pupil marginal contour. An entrance pupil of the imaging optical unit can be upstream of the object field. The imaging optical unit can be well defined regarding its pupil and exhibit desirable properties for projection lithography.