Variable heat exchange device of polycrystal silicon ingot furnace and control method thereof

Abstract

The invention discloses a variable heat exchange device of a polycrystal silicon ingot furnace. A heat exchange table made of graphite is arranged at the lower part of a ceramic crucible, the heat exchange table is provided with a plurality of vertical downward square heat dissipation holes arranged in a matrix, a supporting plate is arranged at the lower part of the heat exchange table, heat preservation plugs are arranged between the heat exchange table and the supporting plate, the heat preservation plugs are made of heat preservation carbon felt, the heat preservation plugs have pyramid structures with small bottoms and big tops, the biggest positions of the bottoms of the heat preservation plugs are just consistent with the sizes of the square heat dissipation holes, the number and the position arrangement of the heat preservation plugs correspond to those of the square heat dissipation holes, the supporting plate is fixed on a lifting rod, and the lifting rod passes through a bottom heat insulation plate from the outer part and extends into the inner part. According to the variable heat exchange device of the polycrystal silicon ingot furnace and the control method thereof, the variable heat exchange device is used in a thermal field, and the lifting rod drives the supporting plate and the heat preservation plugs to move up and down together, so that the heat dissipation capability of the heat dissipation holes is adjusted, the heat dissipation rate below the crystal can be actively controlled, and the growth rate of the crystal is effectively controlled.

Description

technical field [0001] The invention relates to the field of thermal fields of polysilicon ingot furnaces, in particular to a variable heat exchange device of polysilicon ingot furnaces and a control method thereof. Background technique [0002] The thermal field structure of the commonly used polysilicon ingot furnace is as follows: figure 1 As shown, the fixed top insulation board made of thermal insulation carbon felt, the liftable side insulation cylinder and the fixed bottom insulation board form a heat insulation cage. The heat exchange table is placed on the column in the heat insulation cage, and the The bottom and surroundings of the ceramic crucible full of silicon materials are protected by graphite shields. In the melting stage of the silicon material, the side heat insulation cylinder is lowered to zero, and the heat insulation cage is completely closed, and the silicon material in the crucible is heated by the heater until the silicon material is completely me...

AI Technical Summary

Problems solved by technology

The disadvantage of this heat exchange method is that the heat exchange platform is a solid graphite body, the thickness of which is usually between 120mm and 160mm, its heat exchange capacity is very low, and it is passive and invariable. The heat that needs to be dissipated mainly diffuses outward through the surrounding crucible walls and graphite shields, which will cause the temperature of the silicon melt near the surrounding crucible to decrease much faster than the silicon melt at the bottom of the crucible, making the isothermal surface in the crucible unable to maintain a level , the crystal cannot be crystallized from bottom to top in the vertical direction, and the crystal quality is poor; in addition, this heat exchange method usually has a low heat exchange capacity in the later stage of crystal growth, and cannot provide sufficient temperature gradient for crystal growth, resulting in crystal growth The rate of

Therefore, the current thermal field structure of the ingot furnace has defects, resulting in low crystal quality and production efficiency

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