Single crystal ingot puller with high-power laser beam as auxiliary heating source
AssigneeGlobalWafers Co., Ltd.
InventorsVahid Klalajzadeh, Sumeet S. Bhagavat
Life of this patent
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Abstract
A single crystal ingot puller includes a crucible for containing a melt. A single crystal ingot is grown from the melt. A laser system selectively transmits a laser beam to the ingot edge. A controller selectively controls power of the laser to heat the ingot edge such that a local temperature of the edge region is increased.
Claims20
A single crystal ingot puller comprising:
- a crucible for containing a melt;
- a single crystal ingot at least partially grown from the melt, the ingot having a main body defining an outside surface, the outside surface of the ingot contacting a top surface of the melt defining an ingot edge;
- a heater at least partially surrounding the crucible and the ingot;
- a laser system to selectively transmit a laser beam to the ingot edge, wherein the laser system includes a laser affixed to a rail;
- and,
- a controller connected to and selectively controlling power of the laser and the heater, wherein the controller is configured to continuously cycle the laser upward and downward along the rail by a cycle distance.
A single crystal ingot puller comprising:
- a crucible for containing a melt;
- a heater at least partially surrounding the crucible and the ingot;
- a laser system to selectively transmit a laser beam to a first region of a surface of the melt, wherein the laser system includes a laser affixed to a rail;
- and,
- a controller connected to and selectively controlling power of the laser and the heater;
- the controller configured to:
- control the laser to direct the beam to the first region of the surface of the melt;
- control the laser to increase a power of the beam to heat the region such that a local temperature of the first region is increased;
- and
- continuously cycle the laser upward and downward along the rail by a cycle distance.
A method of controlling edge band defect of a crystal ingot pulled in a crystal ingot puller, the crystal ingot puller including a crucible for containing a melt, and a heater, the heater operating at a first temperature, the method comprising:
- pulling the crystal ingot from the melt;
- emitting a high-power laser beam from a laser to an ingot edge defined by an outside surface of the ingot contacting a top surface of the melt;
- cycling, continuously, the laser upward and downward along a rail by a cycle distance, wherein the laser is affixed to the rail;
- and,
- increasing a power of the beam to heat the ingot edge such that a local temperature gradient of the ingot edge is increased, wherein increasing the local temperature gradient of the ingot edge reduces edge band defect in the ingot.
A method of controlling surface temperature of a melt in a crucible of a crystal ingot puller, the crystal ingot puller including a heater, the heater operating at a first temperature, the method comprising:
- emitting a high-power laser beam from a laser to a region of a surface of the melt;
- cycling, continuously, the laser upward and downward along a rail by a cycle distance, wherein the laser is affixed to the rail;
- and,
- increasing a power of the beam to heat the region of the surface of the melt such that a local temperature gradient of an ingot edge of an ingot is increased;
- wherein increasing the local temperature gradient of the ingot edge reduces edge band defect in the ingot.
Dependencies are inferred from the claim text.