Method and apparatus for measuring the diameter of a silicon single crystal

Abstract

A method of measuring the diameter of a silicon single crystal. At intervals of a given rotational period of a pulled single crystal being pulled by the CZ method, optical means samples the luminance distribution of a fusion ring to obtain measured diameter values of the pulled single crystal so that the measured diameter values are processed by a low-pass filter to generate filter output values converted to time series diameter data and the filter output values are subjected to moving averaging to calculate a diameter value. Also, an apparatus for measuring the diameter of a silicon single crystal includes optical means whereby at intervals of a given rotational period of a pulled single crystal being pulled by the CZ method the luminance distribution of a fusion ring is sampled and measured to generate measured diameter values of the pulled single crystal, a low-pass filter for filtering the low-frequency components of the measured diameter values to generate filter output values converted to time series data, and computing means for subjecting the filter output values to moving averaging to calculate a diameter value of the pulled single crystal.

Dependencies are inferred from the claim text.