Patent ID: 8885915
Filing Date: 2014-11-11
Classification: C03B,C30B

Abstract:
1. A method for measuring a distance between a lower end surface of a heat shielding member and a surface of a raw material melt comprising providing the heat shielding member with a criterion reflector, the heat shielding member being located above the surface of the raw material melt, when a silicon single crystal is pulled by the Czochralski method while a magnetic field is applied to the raw material melt in a crucible, the method including: providing the criterion reflector inside a concavity formed on the lower end surface of the heat shielding member; actually measuring the distance between the lower end surface of the heat shielding member and the surface of the raw material melt and observing a position of a mirror image of the criterion reflector with a fixed point observation apparatus, the mirror image being reflected on the surface of the raw material melt; and then measuring a movement distance of the mirror image with the fixed point observation apparatus and calculating the distance between the lower end surface of the heat shielding member and the surface of the raw material melt from the movement distance of the mirror image and the actually measured distance while the silicon single crystal is pulled.