Abstract: There is provided a target object processing method capable of self-breaking a target object with a laser beam. The target object processing method includes: generating a laser beam from a laser beam source; correcting a divergence angle of the generated laser beam; and forming a spot by condensing the corrected laser beam to the inside of the target object. A shape or a size of the spot is adjusted by correcting the divergence angle of the laser beam, a phase transformation area is formed within the target object by the spot, and the target object is subject to self-breaking with the phase transformation area as the starting point.

Abstract: There is provided a laser processing method of a sapphire substrate including preparing a sapphire substrate on which plural stacked portions spaced from each other are formed, irradiating a short pulse laser beam from a laser light source, making the laser beam irradiated from the laser light source pass through a beam shaping module, adjusting a position of a light concentrating unit or the sapphire substrate such that the laser beam is concentrated to the inside of the sapphire substrate through the light concentrating unit, and forming a phase transformation area within the sapphire substrate by irradiating the laser beam into the sapphire substrate. The laser beam is introduced into the sapphire substrate while avoiding an area where the stacked portions are formed on the sapphire substrate, so that the phase transformation area is formed within the sapphire substrate.