| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer processing method capable of suppressing damage to a device on a surface of a wafer due to scattering of a laser beam.SOLUTION: A wafer processing method comprises the steps of: setting a wavelength of a pulse laser beam having permeability to a wafer within a range from 1300 nm to 1400 nm; positioning a condensing point of the pulse laser beam at the inside of the wafer, irradiating the region corresponding to division schedule lines 13a from a rear surface 11b of the wafer with the pulse laser beam, and forming a first modified layer 19a inside the wafer; positioning the condensing point of the pulse laser beam at the upper part of the first modified layer and forming a second modified layer 19b from the rear surface of the wafer; and applying external force to the wafer and dividing the wafer along the division schedule lines using the first and second modified layers as a division start point. When the second modified layer is formed, the condensing point is positioned between mutually adjacent first modified layers.SELECTED DRAWING: Figure 7 |
