Apparatus for producing synthetic quartz glass

US6920766B2 · kind B2 · utility

Assignee

• Schott ML GmbH · DE

Inventors

• Frank Coriand · Jena, DE
• Andreas Menzel · Jena, DE
• Andreas Voitsch · Jena, DE

Key dates

• Filing date: May 30, 2002
• Grant date: Jul 26, 2005
• Expiry date: May 30, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C2203/40
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A synthetic quartz glass preform is produced by flame hydrolysis with subsequent cooling and is suitable for the application of high-energy DUV radiation in the wave length range under 250 nm. The preform has a core area which contains ≧1150 ppm OH, a strain double refraction of ≦5 nm/cm and a resistance to high-energy DUV radiation as a result of a transmission reduction of ΔT ≦0.1%/cm thickness. The quartz glass has been exposed to the following radiation: wavelength λ1=248 nm, laser shot frequency ≧300 Hz, laser shot value ≧109 and lumination ≦10 mJ/cm2, and wavelength λ2=193 nm, laser shot frequency ≧300 Hz, laser shot value ≧109 and lumination <5 mJ/cm2. Apparatus for producing the preform comprises a horizontally positioned muffle with two different sized openings facing each other. The larger of the openings is for removing the preform, the smaller opening being for introducing a burner. The internal chamber of the muffle narrows from the larger opening to the smaller opening.