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:
Dec. 08, 1992
Filed:
Apr. 29, 1991
Masahiko Baba, Annaka, JP;
Shin-Etsu Handotai Company, Limited, Tokyo, JP;
Abstract
A method and an apparatus for measuring oscillation of a melt surface in growing a single crystal by Czochralski process, particularly in growing and pulling a crystal neck portion having a small diameter of 2 to 5 mm. The image of a region where the single crystal is being grown by the Czochralski process is taken by a camera 38 and the outside diameter D.sub.o of a bright ring image 70 of a brightness not lower than a predetermined reference value E is detected in accordance with video signals produced by the camera (Steps 80-83). The amount of oscillation of the outside diameter D.sub.o is measured as the amount S.sub.v of oscillation of the melt surface near the region where the single crystal is grown. The reference value E is determined by multiplying the maximum value of the video signals in one field with a predetermined constant K. The constant K is a value which, when the velocity of pulling of the single crystal is fixed to zero, substantially maximizes the amount of S.sub.v of oscillation of the outside diameter D.sub.o.