Laser processing method and laser processing apparatus

TL;DR: In this article, a laser processing method of a sapphire substrate is described, where the laser beam is introduced into the substrate while avoiding an area where the stacked portions are formed on the substrate, so that the phase transformation area is formed within the substrate.

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.