Recovery of Mo/Si multilayer coated optical substrates

US5698113A · kind A · utility

Assignee

• The Regents of the University of California · US

Inventors

• Sherry Baker · San Diego, US
• Stephen P. Vernon · Pleasanton, US
• Daniel G. Stearns · Los Altos, US

Key dates

• Filing date: Feb 22, 1996
• Grant date: Dec 16, 1997
• Expiry date: Feb 22, 2016

Classification

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

Abstract

Mo/Si multilayers are removed from superpolished ZERODUR and fused silica substrates with a dry etching process that, under suitable processing conditions, produces negligible change in either the substrate surface figure or surface roughness. The two step dry etching process removes SiO.sub.2 overlayer with a fluroine-containing gas and then moves molybdenum and silicon multilayers with a chlorine-containing gas. Full recovery of the initial normal incidence extreme ultra-violet (EUV) reflectance response has been demonstrated on reprocessed substrates.