Method for measuring distance between raw material melt surface and lower end of seed crystal, method for preheating seed crystal, and method for producing single crystal

摘要

An interval measuring method is a method of measuring the intervals on a raw material melt liquid surface and at the lower end of a seed crystal configured on the raw material melt liquid, before cultivating a single crystal at the lower end of the seed crystal by contacting the lower end of the seed crystal with a raw material melt liquid in a crucible, wherein an optical method comprises the steps of obtaining the position information of a real image lower end point and a mirror image point, wherein the real image lower end point is a specific point at the lower end of the seed crystal, and the mirror image point is a point corresponding to the real image lower end point in the mirror image of the seed crystal mapped on the liquid surface; setting the interval between the raw material melt liquid surface and the lower end of the seed crystal as 0 at the point where the positions of the real image lower end point and the mirror image point are consistent, thereby obtaining the interval between the raw material melt liquid surface and the lower end of the seed crystal. By the method, the interval between the raw material melt liquid surface and the seed crystal can be measured accurately before the raw material melt liquid surface and the seed crystal are contacted.