Projection optical unit for EUV projection lithography

US10545323B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Markus Schwab · Aalen, DE
• Hartmut Enkisch · Aalen, DE
• Thomas Schicketanz · Aalen, DE

Key dates

• Filing date: Dec 17, 2018
• Grant date: Jan 28, 2020
• Expiry date: Dec 17, 2038

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70958
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A projection optical unit for EUV projection lithography has a plurality of mirrors for imaging an object field into an image field with illumination light. At least one of the mirrors is an NI mirror and at least one of the mirrors is a GI mirror. A mirror dimension Dx of the at least one NI mirror in a plane of extent (xz) perpendicular to a plane of incidence (yz) satisfies the following relationship: 4 LLWx/IWPVmax<Dx. A mirror dimension Dy of the at least one GI mirror in the plane of incidence (yz) satisfies the following relationship: 4 LLWy/(IWPVmax cos(a))<Dy.