| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of stably and highly reliably pulling up a silicon single crystal even if the weight of the crystal to be pulled up increases by requirements of enlarging the diameter of and extending the length of a grown crystal ingot. SOLUTION: This pull-up method comprises growing a silicon single crystal by the Czochralski method, gripping the prescribed section of the grown single crystal on the way of pulling up by a mechanical grip means, switching load support from the pull-up shaft of a seed crystal to that of the mechanical grip means, and performing the subsequent growing of the single crystal. In this case, based on a speed indication value from the speed control loop of a diameter-control system for controlling a pull-up speed by the diameter measurement value in a single crystal growth boundary, a drive motor for a seed crystal pull-up shaft and that for a grip pull-up shaft are both controlled basically. The silicon single crystal is pulled up by further adding, to the above control, the control for corrections of (a) indication value based on a most recent actual value, (b) change in spring characteristic of a pull-up wire due to its length fluctuation, (c) thermal expansion of the pull-up wire, (d) slope control in rapid change of the indication value and the like. COPYRIGHT: (C)2006,JPO&NCIPI
|
