Crystal pulling apparatus
AssigneeShin-Etsu Handotai Co., Ltd.
InventorsAtsushi Ozaki, Masahiko Urano, Isamu Harada, Tomohiro Kakegawa, Hideki Nakano
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Abstract
A crystal pulling apparatus is disclosed which employs the Czochralski method. The crystal pulling apparatus is operated while a heater for heating a material melt in a crucible is controlled by the main controller of a main system. When maintenance of a heating state is disabled for some reason, a relay of a signal changeover circuit is switched so as to maintain the heating state under control of the backup controller of a backup system, thereby maintaining the material melt in a molten state. Thus, even when it becomes impossible for the main system to heat the material melt within the crucible, the material melt can be prevented from becoming solidified.
Claims4
A crystal pulling apparatus in which a seed crystal is contacted to a melt of a material and is then pulled so as to grow a single crystal, said crystal pulling apparatus comprising:
- a main controller for performing heating control so as to heat the melt, the main controller being included in a main system;
- and
- a backup system for maintaining a heating state of the melt when it becomes impossible for said main controller to maintain the heating state.
Dependencies are inferred from the claim text.