Patent ID: 11890783
Assignee: DISCO CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B  H | IPC B  H

Claim 0:
1. A production method of a wafer from a single-crystal SiC ingot having a planar end face, a c-axis, and a c-plane that intersects the c-axis at right angles, the method comprising:
a cleavage layer creation step of applying a laser beam of a wavelength having transmissivity through single-crystal SiC to the planar end face of the single-crystal SiC ingot, with a focal point of the laser beam positioned in the single-crystal SiC ingot at a wafer depth that is a depth corresponding to a thickness of the wafer to be produced, and then repetitively moving the single-crystal SiC ingot and the focal point relative to each other in a direction parallel to the end face such that multiple cleavage layers each of which contains a modified portion and cracks formed isotropically from the modified portion in the c-plane are created; and
a wafer production step of, after performing the cleavage layer creation step, ejecting ultrasonic water to which ultrasonic vibrations have propagated, from an ultrasonic water ejection nozzle against the end face of the single-crystal SiC ingot, the end face being on a side where the wafer is to be produced, and at a same time, moving the single-crystal SiC ingot and the ultrasonic water ejection nozzle relative to each other in the direction parallel to the end face, thereby severing the wafer along the cleavage layers as starting interfaces to produce the wafer.