Method of producing a quartz glass crucible

US8347650B2 · kind B2 · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Walter Lehmann · Leipzig, DE
• Achim Hofmann · Polling, DE
• Thomas Kayser · Leipzig, DE

Key dates

• Filing date: Jun 29, 2009
• Grant date: Jan 8, 2013
• Expiry date: Dec 26, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C30B15/10
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A method of producing a quartz glass crucible for pulling a single crystal comprising: providing a melting mold comprising a wall having passages between outside and inside; providing an outer layer granulation consisting of first coarser SiO2 particles and forming an outer granulation layer from the outer layer granulation on the inside of the melting mold wall; providing a barrier layer granulation consisting of second finer SiO2 particles and forming a barrier granulation layer from the barrier layer granulation on the outer granulation layer; applying a negative pressure to the outside of the melting mold wall; and heating the barrier granulation layer and the outer granulation layer with formation of a quartz glass crucible with transparent inner layer. In order to produce a sealing layer that is as thin and uniform as possible it is suggested that the SiO2 particles of the barrier layer granulation should have a mean particle size (D50 value) of less than 50 μm and that the formation of the barrier granulation layer should include a measure for fixing the barrier layer granulation to the outer granulation layer.