Patent ID: 9553221
Date: 2017-01-24
CPC Classifications: B22D,C30B,H01L,Y02E

Claim:
1. An electromagnetic casting method of polycrystalline silicon for continuously casting polycrystalline silicon, the method comprising: charging silicon raw materials into a bottomless cold mold; melting the silicon raw materials using electromagnetic induction heating; and pulling down the molten silicon to solidify it, wherein the depth of solid-liquid interface from an upper surface of the molten silicon before the startup of a final solidification process is reduced by reducing a pull down rate of ingot from a prescribed rate in a final phase of a steady-state casting, wherein the prescribed rate is such that molten silicon on the solidified silicon is confined in the solidified silicon when the silicon ingot is pulled at the prescribed rate in the final solidification process, and wherein the reduced pull down rate from the prescribed rate is such that molten silicon on the solidified silicon is not confined in the solidified silicon when the silicon ingot is pulled at the reduced rate in the final solidification process.