| 摘要 |
A method of cutting an object to be processed is provided, which can accurately cut an object to be processed comprising a substrate and a multilayer part provided on the front face of the substrate while having a plurality of functional devices into the functional devices along a line to cut in a short time even when the substrate is thick. A substrate 4 is irradiated with laser light L from the multilayer part 16 side while locating a converging point P within the substrate 4, so as to form a first modified region 71 shifted from the center position CL in the thickness direction of the substrate 4 to the rear face 21 side of the substrate 4 and a second modified region 72 shifted from the center position CL in the thickness direction of the substrate 4 to the front face 3 side of the substrate 4 within the substrate 4 along a line to cut, and generate a fracture 24 from the second modified region 72 to the front face 3 of the substrate 4. Thereafter, while in a state where an expandable tape 23 attached to the rear face 21 of the substrate 4 is expanded, a stress is generated in an object to be processed 1 such as to open the fracture 24. |
