Synthetic quartz glass preform

US6423656B1 · kind B1 · utility

Assignee

• Schott ML GmbH · DE

Inventors

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

Key dates

• Filing date: Sep 10, 1999
• Grant date: Jul 23, 2002
• Expiry date: Sep 10, 2019

Classification

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

Abstract

The invention relates to a synthetic quartz glass preform which is produced according to the flame hydrolysis technique with subsequent cooling and is suitable for the application of high-energy DUV radiation in the wave length range under 250 nm. Said 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 &Dgr; T ≦0.1 %/cm thickness. The quartz glass has been exposed to the following radiation: wavelength &lgr;1=248 nm, laser shot frequency ≧300 Hz, laser shot value ≧109 and rumination ≦10 mJ/cm2, and wavelength &lgr;2=193 nm, laser shot frequency ≧300 Hz, laser shot value ≧109 and rumination ≦5 mJ/cm2. A device for producing said preform comprises a horizontally positioned muffle with two different-sized openings facing each other. The larger of said 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.