An object of the present invention is to provide a method of scribing and breaking a substrate made of a brittle material by which good-quality cutting surface of the substrate can be obtained without any defects such as chippings on the substrate.;The method comprises (a) the first scribing step in the first direction by controlling the relative moving velocity and output power of the laser beam so that local volume shrinkage and local tensile stress can be generated in the vicinity of the formed first scribed line, (b) the second scribing step in the second direction of forming locally trigger cracks, which use tensile stress in the vicinity of the first scribed line and work as a starting point in the second direction, in the vicinity of the intersection of a scribed line in the first direction with a scribed line in the second direction, (c) the first breaking step of breaking the substrate along the first scribed line in the first direction, and (d) the second breaking step of breaking the substrate along the second scribed line in the second direction after the first breaking step and performing the breaking from the trigger that works as a starting point of breaking.
展开▼
