The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 2009
Filed:
Feb. 20, 2004
Yasuo Ohama, Takefu, JP;
Hiroshi Matsui, Takefu, JP;
Yasuo Ohama, Takefu, JP;
Hiroshi Matsui, Takefu, JP;
Heraeus Quarzglas GmbH & Co. KG, Hanau, DE;
Shin-Etsu Quartz Products Co., Ltd., Tokyo, JP;
Abstract
The present invention refers to a method for producing a quartz glass crucible for use in pulling silicon single crystal, said crucible having at least a double-layer structure comprising a pore-free transparent inner layer and an opaque base body or outer layer having pores, characterized in that at least the base body is formed with a silica powder maintained in a gas having a mixing ratio of 0.0005 to 0.0065 kg/kg (dry gas), and a quartz glass crucible produced by said production method. The obtained crucible has an average OH group concentration of 50 ppm or lower and is capable of suppressing the vibration occurring on the surface of silicon melt during pulling the silicon single crystal. Further the obtained crucible suffers less deformation of the crucible on pulling the silicon single crystal.