Patent ID: 7195669
Filing Date: 2007-03-27
Classification: C30B

Abstract:
1. A method for manufacturing a silicon single crystal rod which pulls a silicon single crystal rod ( 24 ) from a silicon melt ( 13 ) made molten by a heater ( 17 ), detects a change in diameter of the silicon single crystal rod ( 24 ) in the pulling process at time intervals, and feeds back an output of the detection to the pulling speed of the silicon single crystal rod ( 24 ) and the temperature of the heater ( 17 ), thereby controlling the diameter of the silicon single crystal rod ( 24 ), and wherein a PID control in which a PID constant is changed on a plurality of stages is applied to controlling the pulling speed of the silicon single crystal rod ( wherein the PID constant in the PID control is increased and the control which gives precedence to the diameter control for the silicon single crystal rod is performed when pulling the top portion of the silicon single crystal rod, and wherein the PID constant in the PID control is gradually reduced and the control which gives precedence to the pulling speed control for the silicon single crystal rod is performed when pulling the portion following the top portion of the silicon single crystal rod.