Patent ID: 7608214

Claim:
A laser processing method of irradiating a planar object to be processed with processing laser light while locating a light-converging point within the object so as to form a modified region to become a starting point region for cutting within the object along a line to cut the object; the method comprising, when an entrance surface of the processing laser light in the object is an irregular surface while the line to cut extends over a depressed area surface and a protruded area surface in the entrance surface: a first step of forming a first modified region inside by a predetermined distance from the depressed area surface along the line to cut; and a second step of forming a second modified region inside by a predetermined distance from the protruded area surface along the line to cut; wherein, in the first step, the light-converging point is located outside the object at the time of irradiation with the processing laser light along a part on the protruded area surface in the line to cut; and wherein, in the second step, the light-converging point is located outside the object at the time of irradiation with the processing laser light along a part on the depressed area surface in the line to cut.