Abstract: There is provided a laser processing device that performs laser processing on an object made of a birefringent material, the device including: a light source that outputs laser light; a spatial light modulator that modulates the laser light output from the light source; a focusing lens that focuses the laser light toward the object; and a polarized light component control unit that is a function of the spatial light modulator to control polarized light components of the laser light such that the laser light is focused on one point in the object in a Z direction (optical axis direction).

Abstract: There is provided a laser processing method for cutting a semiconductor object along a virtual plane facing a surface of the semiconductor object in the semiconductor object. The laser processing method includes a first step of forming a plurality of first modified spots along the virtual plane by causing laser light to enter into the semiconductor object from the surface, and a second step of forming a plurality of second modified spots along the virtual plane so as not to overlap the plurality of first modified spots, by causing laser light to enter into the semiconductor object from the surface.

Abstract: There is provided a laser processing method for cutting a semiconductor object along a virtual plane facing a surface of the semiconductor object in the semiconductor object. The laser processing method includes a first step of forming a plurality of first modified spots along the virtual plane to obtain first formation density, by causing laser light to enter into the semiconductor object from the surface, and a second step of forming a plurality of second modified spots along the virtual plane so as to obtain second formation density higher than the first formation density, by causing laser light to enter into the semiconductor object from the surface after the first step.