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:
Apr. 02, 2013
Filed:
Aug. 11, 2009
Yasuo Ookubo, Tsukuba, JP;
Youichi Hirose, Tsukuba, JP;
Hiroshi Nagata, Tsukuba, JP;
Ulvac, Inc., Chigasaki-Shi, JP;
Abstract
A silicon purification method includes a solidification purification step comprising: preparing the base material to be purified, loading the base material into a crucible, irradiating part of the base material, and fully melting the base material; gradually solidifying the base material by gradually weakening an electron beam so that the solidification proceeds until the solidifying portion occupies a first predetermined ratio of the base material; loading the remnant of the base material into the crucible, and fully melting the remnant of the base material by irradiating the entire area of the remnant of the base material with the electron beam; gradually solidifying the molten metal portion by gradually weakening the electron beam so that the solidification proceeds until the solidifying portion occupies a second predetermined ratio of the molten metal portion; and removing an unsolidified molten metal portion.