Peeling method and peeling apparatus

A peeling apparatus for separating a cylindrical ingot that has a peel-off layer formed therein at the peel-off layer and peeling off a disk-shaped wafer from the ingot, the peeling apparatus comprising:

• an ultrasonic wave applying unit that applies an ultrasonic wave to an upper surface of the ingot via a liquid layer, wherein:
• the ultrasonic wave applying unit includes a first ultrasonic wave applying unit that applies an ultrasonic wave to a first region in the upper surface of the ingot at a first energy density, and
• the liquid layer is supplied to the upper surface of the ingot from an opening of an ultrasonic nozzle of the first ultrasonic wave applying unit;
• and
• a chuck table that has a circular holding surface for holding under suction an outer circumferential region of a lower surface of the ingot, wherein:
• the holding surface includes:
• a flat circular central region,
• an annular suction region that surrounds the central region and communicates with a suction source via a suction channel,
• an outer annular groove within the annular suction region which communicates with the suction source via the suction channel, and
• a flat annular outermost region that surrounds the outer annular groove and is positioned on an outermost side of the holding surface, wherein the flat annular outermost region is defined between the outer annular groove and the outermost side of the holding surface, and
• a width of a portion of the outermost region along a radial direction of the holding surface is equal to or less than 5% of a radius of the holding surface, the portion of the outermost region surrounding an outer circumferential arc-shaped portion of the suction region.