| 摘要 |
PROBLEM TO BE SOLVED: To improve the precision and yield in growing a single crystal by enhancing the accuracy in controlling power inputted to a work coil and to save time and trouble to prepare a profile for each device. SOLUTION: A coil voltage (Vwc) is detected by a coil voltage detecting circuit 20 through the terminal of each work coil 11 while the single crystal growth process proceeds, and the detection result is fed back to a computer control part 18. Command data corresponding to the Vwc profile prepared prior to the growth process are set in the computer control part 18, the firing angle of a thyristor 141 is automatically set so that the coil voltage (Vwc) detected by the circuit 20 coincides with the command data, thereby controlling the power inputted to the work coil 11 variably.
|
