Methods for producing off-orientation single crystal silicon wafers
AssigneeGlobalWafers Co., Ltd.
InventorsCarlo Zavattari, Michael Raffeiner, Paolo Delpero, Peter Albrecht, Fabrizio Bonda, Massimo Gariddi, Patrizio Pregnolato, Pietro Valcozzena, Maria Porrini
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Abstract
Methods for producing an off-orientation single crystal silicon wafer are disclosed. After a single crystal silicon ingot is grown, the single crystal silicon ingot is ground to increase an off-orientation of the single crystal silicon ingot. A wafer is sliced from ground single crystal silicon ingot. The wafer has an off-orientation greater than the ground single crystal silicon ingot.
Claims20
A method for producing an off-orientation single crystal silicon wafer, the method comprising:
- adding a charge of polycrystalline silicon to a crucible disposed in an ingot puller apparatus;
- heating the crucible comprising the charge of polycrystalline silicon to cause a silicon melt to form in the crucible;
- contacting a silicon seed crystal with the silicon melt;
- withdrawing the silicon seed crystal to grow a single crystal silicon ingot, the ingot having a constant diameter portion;
- grinding a segment of the single crystal silicon ingot to increase an off-orientation and produce a ground single crystal silicon ingot segment, the single crystal silicon ingot segment being ground in a grinding apparatus, the grinding apparatus grinding the single crystal silicon ingot along a grinding axis, the single crystal silicon ingot having a longitudinal axis that forms an angle with the grinding axis during grinding, wherein grinding the single crystal silicon ingot segment comprises a one-step on-axis grinding step in which the orientation of the ingot is changed in dual directions without removing the ingot segment from the grinding apparatus;
- and
- slicing a wafer from the ground single crystal silicon ingot segment, the wafer having an off-orientation greater than the ground single crystal silicon ingot segment.
A method for producing an off-orientation single crystal silicon wafer, the method comprising:
- adding a charge of polycrystalline silicon to a crucible disposed in an ingot puller apparatus;
- heating the crucible comprising the charge of polycrystalline silicon to cause a silicon melt to form in the crucible;
- contacting a silicon seed crystal with the silicon melt;
- withdrawing the silicon seed crystal to grow a single crystal silicon ingot, the ingot having a constant diameter portion;
- grinding a segment of the single crystal silicon ingot to increase an off-orientation and produce a ground single crystal silicon ingot segment, the single crystal silicon ingot being ground in a grinding apparatus, the grinding apparatus grinding the single crystal silicon ingot along a grinding axis, the single crystal silicon ingot having a longitudinal axis that forms an angle with the grinding axis during grinding, wherein grinding the single crystal silicon ingot segment comprises a two-step on-axis grinding step in which (1) a crystallographic orientation of the ingot segment is changed in a notch direction and (2) an off-orientation of the ingot segment in a direction 90° from the notch direction is changed in different grinding steps;
- and
- slicing a wafer from the ground single crystal silicon ingot segment, the wafer having an off-orientation greater than the ground single crystal silicon ingot segment.
Dependencies are inferred from the claim text.