Patent ID: 9708731
Date: 2017-07-18
CPC Classifications: C30B,Y10T

Claim:
1. A method of producing a silicon single crystal, comprising pulling a silicon single crystal from a silicon melt formed in a crucible, the method comprising: performing a first operation, with an imaging device, including taking a real image of a heat shield including a circular opening and a mirror image of the heat shield reflected on a surface of the silicon melt, measuring a spacing between the real image and the mirror image, and calculating a position of the surface of the silicon melt; performing a second operation, with the imaging device, including taking an image of a bright zone that appears in a vicinity of an interface between the silicon melt and the silicon single crystal, and calculating a position of the surface of the silicon melt based on a center position of the silicon single crystal determined from the image of the bright zone; and controlling, with a controller, the position of the surface of the silicon melt during the pulling of the silicon single crystal while referring to data of the position of the surface of the silicon melt obtained by the first operation and data of the position of the surface of the silicon melt obtained by the second operation, wherein in performing the first operation: