Video monitoring device for polysilicon growth

Abstract

The invention discloses a video monitoring device for polysilicon growth. The device comprises a vidicon, a video processor and a display, wherein, the vidicon is arranged on the periphery of a polysilicon reducing furnace, and a camera shot of the vidicon coresponds to a view window of the reducing furnace and is used for taking silicon chip images; the video processor is used for processing the silicon chip images and calculating the diameter of the silicon chip; and the display is used for displaying the silicon chip images, the calculated value of the diameter of the silicon chip and various data. The video processor is provided with a video frequency collection module used for collecting image data from the vidicon, a storage module used for storing the collected data, a mathematical model for the diameter calculation of the silicon chip and output data, and a central processing unit used for calculating the diameter of the silicon chip according to the image data and the mathematical model for the diameter calculation of the silicon chip. The device can continuously and accurately measure the real time data of the diameter of the silicon chip to form a diameter-time growth curve, and then further establishes the mathematical model that the addition volume of virgin gas and the heating voltage increase along with the diameter of the silicon chip according to temperature test data, thereby realizing the autocontrol of polysilicon production.

Description

technical field [0001] The invention relates to a device for producing polysilicon by the Siemens method, in particular to a video monitoring device for the device. Background technique [0002] The vast majority of polysilicon production adopts the Siemens method. The principle is to use trichlorosilane and hydrogen to carry out chemical reactions in the reduction furnace. At around 1100 ° C, the reduced silicon crystals are attached to the silicon core as a heater to realize silicon The length of the core is thick. [0003] During the growth process of the silicon core, it is necessary to control the amount of raw material gas added and the heating voltage (current) according to the diameter of the silicon core. Estimate the diameter of the silicon core, and adjust the above-mentioned process parameters of polysilicon production accordingly. Since the diameter of the silicon core is always estimated to be biased, there are the following problems: [0004] 1. It is diffic...

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Problems solved by technology

[0004] 1. It is difficult to accurately control the amount of raw material gas added. If the added amount is too small, the silicon core will grow slowly, the production efficiency will be low, and energy will be wasted; if the added amount is too large, the nascent crystal structure will be loose, the product quality will not be guaranteed, and the reaction will be insufficient. , the excess raw material gas is vented, causing waste and polluting the environment

[0005] 2. The heating voltage (current) is difficult to control accurately, and the temperature of the silicon core deviates from the optimal reaction temperature (1100°C), which has a negative impact on the growth of the silicon core

[0006] 3. The stepless and continuous adjustment of raw material gas addition and heating voltage cannot be realized, the growth rate of silicon core diameter is inconsistent, forming a layered structure similar to tree rings, the low density of each layer is inconsistent, and the product performance is poor

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