| 摘要 |
The invention provides a laser beam machining method characterized by comprising the steps of mounting a protective tape (25) on the surface (3) of a wafer (1a), radiating laser light (L) by using the back (21) of a wafer (1a) as a laser light incidence plane with an optical converging point (P) positioned in a substrate (15) to thereby form a melt processing region (13) for melt processing by multiphoton absorption, forming, by means of the melt processing region (13), a cutting start region (8) on the side within a predetermined distance from the laser light incidence plane along a predetermined cutting line (5) on the wafer (1a), mounting an expand tape (23) on the back (21) of the wafer (1a), and stretching the expand tape (23) to thereby separate a plurality of chip-like portions (24) from each other that are formed by the wafer (1a) being cut with the cutting start region (8) used as the starting point. |
