Reflective optical element

US11099308B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Frank Weigl · Holzheim, DE
• Konstantin Forcht · Aalen, DE
• Horst Feldermann · Aalen, DE

Key dates

• Filing date: Mar 29, 2018
• Grant date: Aug 24, 2021
• Expiry date: Mar 19, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G21K1/062
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A reflective optical element, in particular for a DUV or VUV operating wavelength range, includes a substrate, a dielectric layer system and a metallic coating between the substrate and the dielectric layer system. The dielectric layer system (26) includes a layer (L) of material having a lower refractive index n1 at the operating wavelength, a layer (H) of material having a higher refractive index n2 at the operating wavelength and a layer (M) of material having a refractive index n3 at the operating wavelength, where n1<n3<n2. The layer (M) is arranged at at least one transition from a layer (L) to a layer (H) and/or from a layer (H) to a layer (L). The dielectric layer system has a four-layer sequence of (LMHM)m or (HMLM)m, where m is equal to the number of four-layer sequences in the dielectric layer system.