Measuring method for relative liquid level position of silicon melt in Czochralski silicon single crystal furnace

Abstract

The invention discloses a measuring method for the relative liquid level position of silicon melt in a Czochralski silicon single crystal furnace. Laser reflected by the liquid level of the silicon melt is captured by a CCD (charge coupled device) camera, so that a laser image can be obtained; the circle center of the laser image is obtained through the perfect circle fitting of edge pixel coordinates; and the y coordinate difference between the circle center of the perfect circle fitting diagram of a laser image of any liquid level position and the circle center of the fitting diagram of the initial liquid level position indicates the relative height of the liquid level position. The measuring method provided by the invention is a simple and effective method for precise real-time measurement and control of the relative changes of the liquid level position of the silicon melt in a quartz crucible during the silicon single crystal growth.

Description

technical field [0001] The invention relates to a method for measuring the relative position of the silicon melt liquid level in a Czochralski silicon single crystal furnace. Background technique [0002] The Czochralski method is mainly used to manufacture silicon single crystals. During the growth process of silicon single crystals, the diameter of silicon single crystals needs to be automatically controlled within the target range. In order to stably control the diameter and quality of the silicon single crystal, the relative height of the liquid level of the silicon melt in the furnace body must be kept constant during the growth process of the silicon single crystal. The usual practice is to set a ratio of the rising speed of the crucible to the pulling speed of the silicon single crystal. This ratio is called the crucible ratio. The role of the crucible ratio is based on the assumption that the crucible has no deformation, the shape is very consistent, and the diamete...

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Problems solved by technology

The role of the crucible ratio is based on the assumption that the crucible has no deformation, the shape is very consistent, and the diameter of the silicon single crystal is constant. In fact, the crucible will deform at high temperature during the growth of the silicon single crystal, and the diameter of the silicon single crystal is also within a certain range. Fluctuating, leading to the problem of poor precision when using the crucible ratio to stabilize the silicon melt liquid level position during the growth process of silicon single crystal, and often requires manual adjustment intervention

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