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:
Mar. 27, 2007
Filed:
Jul. 07, 2003
Daisuke Wakabayashi, Tokyo, JP;
Masao Saito, Tokyo, JP;
Satoshi Sato, Tokyo, JP;
Jun Furukawa, Tokyo, JP;
Kounosuke Kitamura, Tokyo, JP;
Daisuke Wakabayashi, Tokyo, JP;
Masao Saito, Tokyo, JP;
Satoshi Sato, Tokyo, JP;
Jun Furukawa, Tokyo, JP;
Kounosuke Kitamura, Tokyo, JP;
Sumitomo Mitsubishi Silicon Corporation, Tokyo, JP;
Abstract
A silicon single crystal rod () is pulled from a silicon melt () made molten by a heater (), and a change in diameter of the silicon single crystal rod every predetermined time is fed back to a pulling speed of the silicon single crystal rod and a temperature of the heater, thereby controlling a diameter of the silicon single crystal rod. A PID control in which a PID constant is changed on a plurality of stages is applied to a method which controls the pulling speed of the silicon single crystal rod so that the silicon single crystal rod has a target diameter and a method which controls a heater temperature so that the silicon single crystal rod has the target temperature. A set pulling speed for the silicon single crystal rod is set so that V/G becomes constant, and an actual pulling speed is accurately controlled so as to match with the set pulling speed, thereby suppressing a fluctuation in diameter of the single crystal rod.