| 摘要 |
The crucible and the side heater are held in the respective initial positions, and the raw material is put into the crucible. These initial positions are positions where the crucible side surface is mainly heated by the side heater. When the side heater heats the crucible side surface, the raw material is melted to form melt. When a part or all of the raw material is melted, the crucible is raised from the initial position or the side heater is lowered from the initial position. At this time, the position of the crucible or the side heater is adjusted such that the amount of heat applied to the lower side curved portion of the crucible side surface is greater than that in the initial relative position between the crucible and the side heater. And, if the crucible bottom part is heated by the side heater while the relative positions of the crucible and the side heater is maintained, the amount of heat applied to the crucible bottom part is increased as compared to the amount of heat applied to the crucible side surface, and the convection in the melt that makes the gas bubbles spatter to the outside. In this way, the gas bubbles are eliminated from the melt. As a result, the amount of gas bubbles in the melt can be reduced without deforming the crucible, and occurrence of pinhole defects in the wafer can be suppressed.
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