Surface correction of mirrors with decoupling coating

US9921483B2 · kind B2 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Oliver Dier · Lauchheim, DE
• Tobias Hackl · Langenau, DE
• Franz-Josef Stickel · Aalen, DE
• Ulrich Loering · Schwäbisch Gmünd, DE
• Tilmann Assmus · Aalen, DE
• Juergen Mueller · Berlin, DE
• Vladimir Kamenov · Oberkochen, DE
• Siegfried Rennon · Würzburg, DE

Key dates

• Filing date: Dec 28, 2015
• Grant date: Mar 20, 2018
• Expiry date: Jan 8, 2036

Classification

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

Abstract

A mirror (1) for EUV lithography includes a substrate (2) and a reflective coating (3, 4). The reflective coating has a first group (3) of layers (3a, 3b) and a second group (4) of layers (4a, 4b), wherein the first group and second group of layers (3a, 3b; 4a, 4b) reflect radiation having a used wavelength between 5 nm and 30 nm. The first group of layers is arranged between the substrate and the second group of layers, and a decoupling coating (6) is arranged between the first group and second group of layers, said decoupling coating optically decoupling the second group of layers from the first group of layers by preventing the radiation having the used wavelength from reaching the first group of layers. The reflective coating preferably has a correction layer (5) having a layer thickness variation for correcting the surface form of the mirror.