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:
Jan. 20, 2015
Filed:
Aug. 20, 2010
Toshiaki Sudo, Akita, JP;
Makiko Kodama, Akita, JP;
Minoru Kanda, Akita, JP;
Hiroshi Kishi, Akita, JP;
Toshiaki Sudo, Akita, JP;
Makiko Kodama, Akita, JP;
Minoru Kanda, Akita, JP;
Hiroshi Kishi, Akita, JP;
Japan Super Quartz Corporation, Akita-Shi, JP;
Abstract
The present invention provides a vitreous silica crucible which can suppress the sidewall lowering of the crucible under high temperature during pulling a silicon single crystal, and a method of manufacturing such a vitreous silica crucible. The vitreous silica crucibleincludes an opaque vitreous silica layerprovided on the outer surface side of the crucible and containing numerous bubbles, and a transparent vitreous silica layerprovided on the inner surface side. The opaque vitreous silica layerincludes a first opaque vitreous silica portionprovided on the crucible upper portion, and a second opaque vitreous silica portionprovided on the crucible lower portion. The specific gravity of the second opaque vitreous silica portionis 1.7 to 2.1, and the specific gravity of the first opaque vitreous silica portionis 1.4 to 1.8, and smaller than that of the second opaque vitreous silica portion. The particle size distribution of the material silica powder for the first opaque vitreous silica portionis wider than that of the second opaque vitreous silica portionand the material silica powder for the first opaque vitreous silica portionincludes more fine powder than that for the second opaque vitreous silica portion