Method of cutting a substrate with localisation of laser modified region near one of the surfaces of the substrate

摘要

A method of cutting a substrate without producing a fusing and a cracking out of a predetermined cutting line on the surface of the work, wherein a pulse laser beam (L) is radiated on the predetermined cut line (5) on the surface (3) of the substrate (1) under the conditions causing a multiple photon absorption and with a condensed point aligned to the inside of the substrate (1), and a modified area is formed inside the substrate (1) along the predetermined determined cut line (5) by moving the condensed point along the predetermined cut line (5), whereby the substrate (1) can be cut with a rather small force by cracking the substrate (1) along the predetermined cut line (5) starting from the modified area and wherein the pulsed laser light (L) is converged at positions closer to the surfaces of the substrate (1) than the center position in the thickness direction of the substrate (1).