Czochralski single crystal silicon diameter measurement method

Abstract

The invention discloses a Czochralski single crystal silicon diameter measurement method, which comprises the following steps of: synchronously acquiring single crystal growth images by using a camera, performing pre-processing and edge detection on the acquired images of each frame, performing sub-pixel optimal approximation and fit of a circle on the images of each frame by adopting a midpoint Bresenham circle drawing algorithm, and performing mean filter on the basis of a fit arc to acquire the accurate diameter of single crystal. The method can perform the sub-pixel optimal approximation of the circle by adopting the midpoint Bresenham circle drawing algorithm and can accurately calculate the diameter of the single crystal by using the common analog industrial camera so as to achieve the measurement effect of the high-resolution industrial camera.

Description

technical field [0001] The invention belongs to the technical field of on-line real-time measurement of single crystal diameter in Czochralski single crystal method. Background technique [0002] At present, the CCD camera scanning system is the mainstream technology for measuring the diameter of large-diameter Czochralski single crystals. The non-high-definition dual-CCD video camera measurement system using ordinary lenses is the most widely used Czochralski single-crystal CCD video camera measurement system at present. Due to the use of low-resolution image sensors, the dual-CCD camera measurement system has high requirements for image detection algorithms. Currently, the commonly used algorithm processes mainly include image preprocessing, edge detection, arc fitting, and diameter measurement. The Chinese invention patent with the patent number of 200610105331.7 disclosed on August 1, 2007 a method for measuring the diameter of Czochralski single crystal silicon rods ba...

AI Technical Summary

Problems solved by technology

[0003] 1. Because the coated glass of the observation window on the single crystal furnace often peels off and stains, it will interfere with the results of image preprocessing, especially the interference points near the aperture, which will cause a large measurement error to the traditional measurement algorithm , it is difficult to remove, only through frequent cleaning or replacement of coated glass

[0004] 2. The aperture image during the crystal growth process is an irregular circle. Due to the position and angle of the camera, the aperture image is an incomplete circle with distortion

The traditional algorithm requires the lowest point of the arc as the reference point to measure the diameter. The shaking of the aperture and the irregularity of the single crystal silicon during the process of seeding and equal diameter will lead to inaccurate reference points and will also cause measurement errors.

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