Melting height control method of ingot casting crystal seed and polycrystalline silicon ingot casting furnace

Abstract

The invention relates to a melting height control method of an ingot casting crystal seed. The melting height control method comprises the following steps of: controlling a heat field, and gradually melting the crystal seed laid in a crucible and polycrystalline silicon raw material above the crystal seed; utilizing a thermocouple to obtain a temperature sudden change signal on the side wall of the crucible; and judging the melting height of the crystal seed according to the obtained signal, and controlling the heat field to jump from a melting stage to a crystal growth stage when the crystal seed is melted to the set height. In the melting height control method of the ingot casting crystal seed, the temperature sudden change signal on the side wall of the crucible is detected through the thermocouple, and the melting height of a silicon solution can be judged, so that the heat field can be controlled to jump from the melting stage to the crystal growth stage when the crystal seed is melted to the set height, and then the remaining height of the crystal seed can be controlled; and the method has the characteristics of high precision and low cost. Additionally, the invention further provides a polycrystalline silicon ingot casting furnace which can implement the method.

Description

technical field [0001] The invention relates to the technical field of photovoltaic silicon wafer production, in particular to a method for controlling the melting height of an ingot seed crystal and a polysilicon ingot furnace. Background technique [0002] Solar photovoltaic power generation is one of the forms of sustainable energy utilization, and it has developed rapidly in various countries in recent years. At present, crystalline silicon solar cells are the most widely used, and crystalline silicon solar cells are mainly made of Czochralski monocrystalline silicon wafers (CZ) or ingot polycrystalline silicon wafers (DSS). Czochralski monocrystalline silicon has high photoelectric conversion efficiency, but low production capacity and high production cost; ingot polycrystalline silicon wafers occupy a dominant position in solar cells due to high production capacity and low cost, but compared with Czochralski monocrystalline silicon, the efficiency of ingot polycrystall...

AI Technical Summary

Problems solved by technology

At present, the industry mainly uses quartz rods to manually measure and control the remaining height of the seed crystal, but this method requires the operator to maintain a high degree of vigilance and perform multiple measurements, which is prone to large errors and personnel forgetting to measure, resulting in unstable production , Production costs cannot be reduced, etc. In addition, high-purity quartz rods are expensive and are consumable products, which will bring a large increase in production costs

In addition, recently, a few experienced technicians have proposed that the remaining height of the seed crystal can be judged by the slight change rate of the temperature at the bottom of the crucible in the later stage of melting, but this method requires very experienced professionals, and this method has great risks

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