Provided is a cylindrical ingot manufacturing method including: an operation of supplying a silicon raw material to an inside of a crucible and heating the crucible to melt the silicon raw material; an operation of supplying a seed crystal having one end fastened to a seed shaft to the inside of the crucible; and an operation of moving the seed crystal from a lower portion of the crucible to an upper portion thereof by the crucible rotating in one direction relative to the seed shaft and the seed shaft rotating in the other direction and moving upward. According to the present disclosure, since a ring-shaped seed crystal is grown, a cylindrical silicon ingot can be manufactured, and since a cylindrical silicon ingot having an inner diameter is formed, a wafer retaining ring can be manufactured from the ingot without a coring task.

Provided is a cylindrical ingot manufacturing method including: an operation of supplying a silicon raw material to an inside of a crucible and heating the crucible to melt the silicon raw material; an operation of supplying a seed crystal having one end fastened to a seed shaft to the inside of the crucible; and an operation of moving the seed crystal from a lower portion of the crucible to an upper portion thereof by the crucible rotating in one direction relative to the seed shaft and the seed shaft rotating in the other direction and moving upward. According to the present disclosure, since a ring-shaped seed crystal is grown, a cylindrical silicon ingot can be manufactured, and since a cylindrical silicon ingot having an inner diameter is formed, a wafer retaining ring can be manufactured from the ingot without a coring task.

A measurement system includes a target object at least partially visible through an opening in a crystal puller. The crystal puller has a silicon melt in a crucible and a reflector defining a central passage through which a crystal is pulled. A detector array captures light through the opening. The detector array is directed to a surface of the silicon melt in the crystal puller and to the target object, and a laser selectively transmits a coherent light beam through the opening to the target object to produce a reflection of the target object on the surface of the silicon melt. An optical modulator pulses the coherent light beams of the laser into discrete coherent light beams having a period, and a lock-in amplifier is connected to the detector array to filter discrete coherent light having the period from captured light.

A measurement system includes a target object at least partially visible through an opening in a crystal puller. The crystal puller has a silicon melt in a crucible and a reflector defining a central passage through which a crystal is pulled. A detector array captures light through the opening. The detector array is directed to a surface of the silicon melt in the crystal puller and to the target object, and a laser selectively transmits a coherent light beam through the opening to the target object to produce a reflection of the target object on the surface of the silicon melt. An optical modulator pulses the coherent light beams of the laser into discrete coherent light beams having a period, and a lock-in amplifier is connected to the detector array to filter discrete coherent light having the period from captured light.