Illumination optical device for projection lithography

US11003086B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Stig Bieling · Aalen, DE
• Markus Deguenther · Aalen, DE

Key dates

• Filing date: Jul 9, 2020
• Grant date: May 11, 2021
• Expiry date: Jul 9, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/702
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

An illumination optical unit for projection lithography illuminates an object field. The illumination optical unit has an optical rod with an entrance area and an exit area for illumination light. The optical rod is configured so that the illumination light is mixed and homogenized at lateral walls of the optical rod by multiple in-stances of total internal reflection. At least one correction area serves to correct a field dependence of an illumination angle distribution when illuminating the object field. The correction area is disposed in the region of the exit area of the optical rod. This can result in an illumination optical unit, in which an unwanted field dependence of a specified illumination angle distribution is reduced or entirely avoided, even in the case of illumination angle distributions with illumination angles deviating extremely from a normal incidence on the object field.