Thermal field structure of polysilicon ingot casting furnace

The invention relates to a thermal field structure of a polysilicon ingot casting furnace, which comprises a furnace body, a thermal-insulation cage body and a crucible, wherein the thermal-insulation cage body is arranged inside the furnace body, the crucible is arranged inside the thermal-insulation cage body, and the thermal-insulation cage body is a sealed thermal field chamber formed by an upper thermal-insulation body, a lower thermal-insulation body and a thermal-insulation baseplate; the upper thermal-insulation body is fixed on the furnace body; the bottom of the lower thermal-insulation body is placed on the thermal-insulation baseplate, and the lower thermal-insulation body can slide up and down relative to the upper thermal-insulation body through a lifting mechanism; the crucible is placed on a heat exchange platform in a supporting structure; and the thermal-insulation baseplate is placed on supporting columns of the supporting structure for fixation. In the invention, when a silicon material is