Method and measuring device for detecting molten silicon liquid level of a single crystal silicon crystal pulling furnace

Abstract

The invention discloses a method and a device for detecting a molten silicon liquid level of a monocrystalline silicon crystal pulling furnace. The method comprises the following steps: installing a liner laser and a camera at a viewing port of a single crystal furnace, and slantly irradiating a liner laser beam from the viewing port of the crystal pulling furnace onto a heat shield and a molten silicon liquid level, wherein the molten silicon liquid level performs mirror reflection on the laser beam irradiated thereon, a reflected light beam is projected onto the heat shield, and the projective light beam on the heat shield also can be projected onto the molten silicon liquid level. Along with change of the molten silicon liquid level, a contact point of the laser beam and the molten silicon liquid level also changes, so that the distance from the reflected light beam on the heat shield to the projection on the molten silicon liquid level also changes, therefore, positions of pixels of the light beam received by the camera are changed; actual liquid level change information can be obtained by calibrating position change of a pixel between two projection points on an image and the actual position change of the molten silicon liquid level.

Description

technical field [0001] The invention relates to a method for detecting the liquid level of molten silicon in a non-contact crystal pulling furnace, in particular to a method for detecting the liquid level of molten silicon in a single crystal silicon pulling furnace and a measuring device based on the method. Background technique [0002] The Czochralski method uses the condensation crystallization driving principle of the melt. At the interface between solid and liquid, the phase change from liquid to solid occurs due to the temperature drop of the melt. Single crystal silicon grown by the Czochralski method has a high oxygen content and a large diameter, which is a method widely used at present. However, this method imposes strict requirements on the growth environment of the single crystal. With the continuous growth of monocrystalline silicon solids, the volume of molten silicon in the crucible gradually decreases, and the liquid level of molten silicon continues to drop...

AI Technical Summary

Problems solved by technology

Therefore, the commonly used eddy current detection method and capacitance detection method cannot be applied to the liquid level detection system.

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