Patent ID: 11969916
Assignee: DISCO CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A wafer forming method for forming a wafer from a semiconductor ingot having an upper surface, a lower surface, and a side surface, the wafer forming method comprising:
a modified layer forming step of applying a first laser beam to the semiconductor ingot, with a focal point of the first laser beam positioned inside from the side surface at a position corresponding to a thickness of a wafer to be formed, to form a modified layer over a whole circumference of the side surface or in an arcuate shape;
a peeling-off layer forming step of exerting an external force from the upper surface of the semiconductor ingot and concentrating a stress on a crack extending from the modified layer to the inside to cause the crack to develop from the side surface side toward the inside, thereby forming a peeling-off layer, wherein the external force exerted from the upper surface of the semiconductor ingot is a second laser beam which is set at a comparatively weak output compared to an average output of the first laser beam; and
a wafer forming step of peeling off the wafer to be formed, from the semiconductor ingot, with the peeling-off layer as a start point, to form the wafer.