Patent ID: 8389384

Claim:
A laser processing method of irradiating an object to be processed comprising a substrate and a plurality of functional devices formed on a front face of the substrate with laser light while locating a converging point within the substrate, so as to form a modified region serving as a cutting start point within the substrate along a cutting line used to cut the object; the method including the step of forming at least one row of a first modified region, at least one row of a second modified region positioned between the first modified region and the front face of the substrate, and at least one row of a third modified region positioned between the first modified region and a rear face of the substrate; wherein a forming density per one row of the first modified region extending in a cutting line direction along the cutting line is lower than that per one row of the second modified region extending in the cutting line direction and that per one row of the third modified region extending in the cutting line direction.