In manufacturing a silicon single crystal by the CZ method, a variety of foreign substances, such as vapor during pulling, wear debris of a wire, carbon dust due to degradation of carbon parts, quartz chippings occurring from a crack in a quartz crucible during crystal cooling, and chippings of residual silicon, adhere to various locations in the single crystal pulling apparatus after a pulling step ends. If the next pulling step is performed without cleaning such locations, the foregoing foreign substances come off and adhere to a single crystal in growth and cause first dislocation generation. Overhauling and cleaning of the chamber and the parts in the chamber, including wiping, vacuuming, and air blowing, are therefore performed each time a pulling step ends.
However, it is difficult to completely clean in every corner of the single crystal pulling apparatus because the structure thereof is complicated. The generation rate of dislocation of a single crystal is therefore not able to be reduced by overhauling and cleaning alone.
To solve the foregoing problem, Patent Document 1 proposes a cleaning apparatus for cleaning the inner surface of a pull chamber and a wire hung in the pull chamber which are difficult to manually clean. Patent Document 2 proposes a method for vacuuming the interior of a chamber after the single crystal pulling apparatus is overhauled and cleaned and parts are set in the chamber and before a quartz crucible is loaded with material.
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