| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method capable of suppressing a device on a surface of a silicon wafer from being damaged by transmitted light when forming a modified layer inside the wafer by irradiating the wafer with a pulse laser beam having a wavelength set within a range from 1300 nm to 1400 nm.SOLUTION: A wafer processing method comprises the steps of: setting a wavelength of a pulse laser beam within a range from 1300 nm to 1400 nm; branching the pulse laser beam into a first pulse laser beam LB3 having a first power and a second pulse laser beam LB4 having a second power smaller than the first power, and delaying the first pulse laser beam to the second pulse laser beam by a prescribed time (LB5); and softening the wafer by heating it with a second pulse laser beam LB7, and forming a modified layer in the softened region using a first pulse laser beam LB6 with a prescribed time difference immediately after softening the wafer.SELECTED DRAWING: Figure 6 |
