Patent ID: 8728914
Filing Date: 2014-05-20
Classification: B23K,C03B,H01L

Abstract:
1. A method of cutting an object to be processed, the method of irradiating a sheet-like object to be processed equipped with a silicon substrate with a laser light so as to form a modified region in the silicon substrate along a line to cut the object and cutting the object along the line from the modified region acting as a cutting start point, the method comprising the steps of: forming a first modified region as the modified region so as to generate a first fracture from the first modified region to one main face of the object along the line, and a second modified region as the modified region on the other main face side of the first modified region such that an unmodified region is interposed between the first and second modified regions so as to generate a second fracture from the second modified region to the other main face along the line without connecting the second fracture to the first fracture in the unmodified region; and generating a stress in the object so as to connect the first and second fractures to each other and cut the object along the line, when forming a third modified region as a modified region in the unmodified region interposed between the first and second modified regions after forming the first modified region before forming the second modified region, the laser light is modulated by a spatial modulator according to a modulation pattern including a quality pattern, an individual difference correction pattern for correcting an individual difference occurring in a laser machining device, and a spherical aberration correction pattern for correcting the spherical aberration occurring depending on a material of the object and a distance from a laser light entrance surface of the object to the converging point of the laser light; and wherein, when forming the first and second modified regions, the laser light is modulated by the spatial light modulator according to a modulation pattern including the individual difference correction pattern and the spherical aberration modulation pattern.